A case-control study of risk factors for death from 2009 pandemic influenza A(H1N1): is American Indian racial status an independent risk factor?

T. W. HENNESSY; D. BRUDEN; L. CASTRODALE; K. KOMATSU; L. M. ERHART; D. THOMPSON; K. BRADLEY; D. R. O'LEARY; J. McLAUGHLIN; M. LANDEN; the Investigative Team

doi:10.1017/S0950268815001211

A case-control study of risk factors for death from 2009 pandemic influenza A(H1N1): is American Indian racial status an independent risk factor?

Published online by Cambridge University Press: 29 June 2015

D. BRUDEN ,

K. KOMATSU ,

K. BRADLEY ,

J. McLAUGHLIN and

T. W. HENNESSY*: Affiliation:
Arctic Investigations Program, US Centers for Disease Control and Prevention (CDC), Anchorage, AK, USA
D. BRUDEN: Affiliation:
Arctic Investigations Program, US Centers for Disease Control and Prevention (CDC), Anchorage, AK, USA
L. CASTRODALE: Affiliation:
State of Alaska, Division of Public Health, Anchorage, AK, USA
K. KOMATSU: Affiliation:
Arizona Department of Health Services, Phoenix, AZ, USA
L. M. ERHART: Affiliation:
Arizona Department of Health Services, Phoenix, AZ, USA
D. THOMPSON: Affiliation:
New Mexico Department of Health, Santa Fe, NM, USA
K. BRADLEY: Affiliation:
Oklahoma State Department of Health, Oklahoma City, OK, USA
D. R. O'LEARY: Affiliation:
Wyoming Department of Health, Cheyenne, WY, USA
J. McLAUGHLIN: Affiliation:
State of Alaska, Division of Public Health, Anchorage, AK, USA
M. LANDEN: Affiliation:
New Mexico Department of Health, Santa Fe, NM, USA
*: *Author for correspondence: T. W. Hennessy, MD, MPH, CDC Arctic Investigations Program, 4055 Tudor Centre Drive, Anchorage, Alaska 99508, USA. (Email: [email protected])

Article contents

Summary
INTRODUCTION
METHODS
RESULTS
DISCUSSION
References

Rights & Permissions

Summary

Historically, American Indian/Alaska Native (AI/AN) populations have suffered excess morbidity and mortality from influenza. We investigated the risk factors for death from 2009 pandemic influenza A(H1N1) in persons residing in five states with substantial AI/AN populations. We conducted a case-control investigation using pandemic influenza fatalities from 2009 in Alaska, Arizona, New Mexico, Oklahoma and Wyoming. Controls were outpatients with influenza. We reviewed medical records and interviewed case proxies and controls. We used multiple imputation to predict missing data and multivariable conditional logistic regression to determine risk factors. We included 145 fatal cases and 236 controls; 22% of cases were AI/AN. Risk factors (P < 0·05) included: older age [adjusted matched odds ratio (mOR) 3·2, for >45 years vs. <18 years], pre-existing medical conditions (mOR 7·1), smoking (mOR 3·0), delayed receipt of antivirals (mOR 6·5), and barriers to healthcare access (mOR 5·3). AI/AN race was not significantly associated with death. The increased influenza mortality in AI/AN individuals was due to factors other than racial status. Prevention of influenza deaths should focus on modifiable factors (smoking, early antiviral use, access to care) and identifying high-risk persons for immunization and prompt medical attention.

Keywords

Infectious disease epidemiology influenza pandemic

Type: Original Papers
Information: Epidemiology & Infection , Volume 144 , Issue 2 , January 2016 , pp. 315 - 324

DOI: https://doi.org/10.1017/S0950268815001211 [Opens in a new window]
Copyright: Copyright © Cambridge University Press 2015

INTRODUCTION

During the 2009 influenza A(H1N1) pandemic (pH1N1), North American Indigenous populations suffered disproportionately compared to the general population, as shown by higher rates of influenza-like illness [Reference Dee1], hospitalizations [Reference Wenger2–Reference Thompson4], intensive care unit admissions [Reference Thompson4–Reference Zarychanksi6] and a fourfold increased rate of death [7]. We conducted a case-control investigation to determine risk factors for death due to pH1N1 in five US states with large American Indian/Alaska Native (AI/AN) populations. Our objectives were to determine: (1) whether AI/AN racial status was an independent risk factor for death and, (2) the risk factors for death within the AI/AN population.

METHODS

This investigation was conducted in Alaska, Arizona, New Mexico, Oklahoma and Wyoming. Case-patients (cases) were state residents who died related to infection with laboratory-confirmed influenza A from 15 April 2009 to 31 January 2010. Influenza infection was defined by a positive polymerase chain reaction (PCR) test, viral culture confirming pH1N1, a rapid influenza A test, or a direct fluorescent antibody test on a specimen collected from 15 April to 31 December 2009. We excluded cases who had no contact with a healthcare provider in the 14 days before death, or whose death and illness onset occurred when the person was located outside their state.

We attempted to match cases with two control-patients based on state of residence and influenza specimen date (within 14 days). Controls were state residents who had laboratory-confirmed pH1N1 infection (confirmed by PCR or culture) from 15 April to 31 December 2009 and who were not hospitalized for influenza within 30 days after their specimen collection date. Cases and controls were identified from death certificates and notifiable disease reports. Death certificates and medical records were abstracted using a standard form. Additionally, we interviewed a case proxy, defined as an adult who lived with or cared for the case prior to their illness, or a relative or close friend who lived nearby, or a relative knowledgeable of the case. If no case proxy was interviewed, we abstracted seven of the questions from the medical record. Interviews began in October 2010 and ended March 2012. Data on fatalities from influenza for the US population was obtained from national surveillance.

Four of the states required reporting of positive laboratory tests for pH1N1 (PCR and culture). Oklahoma obtained laboratory data from tests performed by its Public Health Laboratory. Outpatients with pH1N1 were randomly selected and contacted for an interview. Participants' individual medical records were obtained and we abstracted demographic information, height, weight, health insurance status, medical and vaccination history, and influenza illness treatments. From interviews we obtained self-identified race, household characteristics, access to healthcare, past medical history, tobacco and alcohol habits, income and educational attainment.

Data were double-entered into Paradox v. 9·0 (Corel, Canada). Univariable tests were run in a conditional logistic regression model using the Wald χ ² statistic. Households with ⩾1·5 persons per room were considered crowded and poverty was defined as having an annual household income <US$ 25 000 [Reference Blake, Kellerson and Simic8]. Obesity was defined as a body mass index (BMI) ⩾30 (adults), a BMI ⩾95th percentile for age (2–17 years), or ⩾95th percentile of weight for age (<2 years). Influenza-like illness was defined by a reported fever, and either a cough or a sore throat. Age was modelled using three age groups (<18, 18–44, ⩾45 years). Receipt of antiviral medications was categorized into three levels: none, received ⩽2 days after symptom onset, received ⩾3 days after symptom onset.

Missing data ranged from 0% (age) to 25% (income). Missing data imputation procedures were employed, assuming data were missing at random. Data were imputed using Markov chain Monte Carlo iterations assuming a multivariable normal distribution [Reference Allison9–Reference Lee and Carlin11]. The imputation model included variables for state of residence and specimen collection date, and all variables in the univariable analyses and case-control membership. Dichotomous variables derived from continuous variables were imputed in their continuous form; other dichotomous variables were imputed as dichotomous indicators [Reference Allison9, Reference Bernaards, Belin and Schafer10]. We created 20 imputed datasets for the multivariable models [Reference Graham, Alchowski and Gilreath12]. A single chain was used with 200 burn-in iterations and 100 iterations between datasets. Each imputed dataset was analysed using conditional logistic regression and then estimates were combined accounting for the parameter variability estimates and the variability associated with the imputation process. Analyses were conducted in SAS using logistic and imputation procedures [Reference Yuan13]. Multivariable models used purposeful forward selection and included variables with a univariate P value <0·25 [Reference Hosmer and Lemeshow14]. After determining main effects, all two-way interactions with appropriate sample sizes were evaluated for statistical significance. Variable selection was repeated on the imputed datasets using the combined Wald χ ² statistic that incorporated the between- and within-imputation variation components [Reference Wood, White and Royston15]. Multivariable models included: the imputation model and a complete case analysis, where matched pairs or observations were entered or missing based on whether they had missing data for any given risk factor in the model.

A multivariable model restricted to AI/AN persons evaluated a subset of factors, due to sample size limitations, including demographics, healthcare access, one socioeconomic variable, and all other variables that had adequate sample sizes. The variables that were used to match cases and controls were considered independent predictors in this model. Model diagnostics were run to identify influential observations or matched pairs in terms of model fit and parameter point and variance estimates. All P values were two-sided and a value <0·05 was considered statistically significant.

Human participant protection and tribal review

The investigation was determined to be a non-research public health practice investigation by CDC and the Indian Health Service. Additional human subjects review and approval was obtained: Alaska Area IRB; Arizona: Navajo Nation Health Research Review Board, Arizona Department of Health Services – Human Subjects Review Board, Gila River Indian Community – Research Review Committee; New Mexico: New Mexico State University IRB, Southwest Tribal IRB, Navajo Nation Human Research Review Board; Oklahoma State Department of Health IRB; Wyoming Department of Health IRB. The protocol was approved by the following Tribal entities: Arizona: San Carlos Apache Tribe – Health Committee, San Carlos Apache Tribe Tribal Council, Tohono O'odham Nation – Health and Human Services Committee, Tohono O'odham Legislative Council, Alaska Native Tribal Health Consortium; Oklahoma City Area Intertribal Health Board; Wyoming: Eastern Shoshoni and Northern Arapahoe Tribes Montana/Wyoming Tribal Leaders Council/Rocky Mountain Tribal Epidemiology Center.

RESULTS

A total of 257 fatalities associated with influenza A infection were reported in these states (annualized mortality: 6·6/100 000 persons per year). Of these, 145 met the case definition (Table 1). The epidemic peak occurred during calendar weeks 40–44, similar to the overall US epidemic (Fig. 1). Thirty-two fatalities were excluded, principally because they did not see a healthcare provider prior to death (90%); 69% of excluded cases were from Arizona. Eighty fatalities from Arizona were not included in analysis because of incomplete data or because Tribal approvals were not obtained. These persons were similar to the cases included from Arizona with regard to sex, age, diagnosis date, and underlying medical conditions; however, those not included were more likely to be of AI/AN racial status than the included fatal cases (26% vs. 11%, P = 0·01).

Fig. 1. Fatal influenza cases by week of death, 2009, for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming) and overall United States.

Table 1. Characteristics of participants, influenza mortality investigation for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

* Twelve outpatient controls did not have a chart review completed and sex was not determined.

† Residence type only available for 88 (61%) of the cases and 210 (89%) of the controls.

‡ Twenty-two persons listed ‘Hispanic’ as their race and one person listed ‘Filipino’.

§ Results reflect medical chart review results. All controls were reported to the state health department as having a positive culture or PCR for pH1N1.

We recruited 236 controls; 91 (63%) cases were matched to two controls and 54 were matched to one control. Proxy interviews could not be obtained for 43 (30%) fatal cases. Univariate risk factors for death are shown in Table 2. Multivariable analysis identified four independent risk factors for a fatal infection (Table 3): older age, having a pre-existing medical condition, being a smoker and receiving antivirals ⩾3 days after illness onset. Using the imputed dataset, a fifth independent variable was identified: a financial or transportation-related barrier to healthcare access. AI/AN race was not significantly associated with death after adding age and pre-existing conditions to the models. There were no significant two-way interactions between the risk factors in the final models.

Table 2. Univariate risk factors for death due to H1N1 in a matched case-control investigation, five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

mOR, Matched odds ratio; CI, confidence interval; BMI, body mass index; AI/AN, American Indian/Alaska Native. * Odds provided for a 10-year increase in age; odds for a single year increase was 1·04.

† Odds, case numbers, percentages and P values for those aged ⩾7 years.

‡ Odds and P value for persons aged ⩾18 years.

§ Alcohol abuse noted in chart or ⩾15 drinks/month.

|| Includes asthma, chronic lung disease, cardiovascular disease, diabetes, other chronic metabolic disease, cancer (last 12 months), renal disease, liver disease, neuromuscular disease, blood disorder, aged <19 years with aspirin therapy, immunosuppressive condition, and alcohol abuse.

Table 3. Risks factors for influenza mortality, multivariable results for matched case-control investigation, for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

mOR, Matched odds ratio; CI, confidence interval; AI/AN, American Indian/Alaska Native; n.s., not significant, removed from model.

* n = 258 observations in the final model for all races (from 106 case-control matches), and n = 63 observations in the final model for AI/AN race.

† n = 381 observations the final model for all races (from 145 case-control matches), and n = 70 observations in the final model for AI/AN race.

‡ For AI/AN race model, OR are not matched.

Mortality risk factors for the 70 AI/AN participants are given in Table 4. Multivariable analysis identified two independent risk factors for death: pre-existing medical conditions and obesity (Table 3). Using the imputed data, a third independent risk factor was identified: having been a smoker.

Table 4. Univariate risk factors for influenza mortality in American Indian/Alaska Native persons (alone or in combination with other races), for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

OR, Odds ratio; CI, confidence interval.

* Test if overall mean specimen date differs between American Indian/Alaska Native cases and controls.

† In those aged ⩾18 years.

‡ Comparing those who received antivirals (⩽2 days and ⩾3 days combined) to those who did not.

§ Comparing those who received antivirals ⩾3 days after symptom onset to those receiving antivirals ⩽2 days after symptom onset.

DISCUSSION

In this case-control investigation from US states with substantial AI/AN populations, we used medical records and interviews to assess potential risk factors for pH1N1 influenza A mortality. Three of the risk factors are modifiable (smoking, delayed receipt of antiviral medications, and a barrier to accessing healthcare). The association of death with smoking and a barrier to healthcare access have not been previously described for influenza [Reference Epstein, Reynaldo and Nelson El-Amin16, Reference Regan17]. Two other risk factors (older age and underlying medical conditions) are well recognized. AI/AN persons were overrepresented in the fatal cases (22% vs. 16% of controls, P = 0·05); however, AI/AN racial status was not an independent risk for death. The risk factors for death in the AI/AN population (pre-existing medical conditions, smoking, obesity) are similar to other North American populations [Reference Regan17–Reference Morgan19]. This is the first population-based investigation to evaluate AI/AN race as a potential risk factor for influenza mortality and the first to evaluate influenza mortality risk factors in the AI/AN population.

Smoking has not been previously identified as a risk factor for influenza mortality [Reference Epstein, Reynaldo and Nelson El-Amin16]. Other studies of mortality risk during this pandemic either did not evaluate smoking [Reference Regan17, Reference Fowlkes18] or did not show an association when they compared fatal and hospitalized patients [Reference Zarychanski20, Reference Kumar, Zarychanski and Pinto21]. The prevalence of smoking in controls (11% for those aged ⩾7 years) was much lower than the adult smoking prevalence in these states, which ranges from 19·2% to 26·1% [22]. This could have led to an overestimation of the magnitude of this risk factor. Despite this potential limitation, smoking is a biologically plausible risk factor and should be investigated further.

The financial or transportation-related barriers to healthcare access may have caused patients to delay seeking care after illness onset, resulting in more severe illness that was less amenable to treatment. Although 93% of the fatal cases had health insurance, insurance coverage differs with regard to costs paid by the patient and healthcare-seeking behaviour is complicated. Further investigation is needed to identify ways to reduce barriers to healthcare in high-risk individuals, with and without health insurance.

Whether AI/AN race is, by itself, a risk factor for death or is a marker for other factors has substantial implications. Finding that AI/AN racial status was a risk factor might imply an undiscovered genetic susceptibility to severe influenza. A genetic explanation offers limited prevention options and could have a chilling effect on efforts to reduce influenza mortality in AI/AN populations [Reference Jones23]. Because AI/AN race is a marker for other risk factors, we can now focus on those modifiable risks in AI/AN persons. Three risk factors from the AI/AN-specific model were common among fatal cases (obesity 61%, smoking 35%, pre-existing conditions 69%). Similar to the overall population, we observed trends in AI/AN persons for higher mortality for older age, delay in antivirals (cases 36%, controls 9%), and healthcare access barriers (cases 35%, controls 11%). Accessing healthcare is a problem for AI/AN persons with influenza [Reference Dee1]. Of adults in 2009, AI/AN persons had the highest frequency of influenza-like illness of any racial group (16·2% vs. 8·2% overall), yet were the least likely to seek healthcare (37·4% vs. 42·1% overall). Further efforts are indicated to improve access and healthcare-seeking behaviour in AI/AN persons. Environmental determinants for lower respiratory tract infections common in AI/AN populations deserve further attention. These include household crowding [Reference Bulkow24, Reference Singleton25], limited access to in-home water and sanitation services [Reference Hennessy26–Reference Wenger28], and household air pollution from wood-burning stoves or second-hand tobacco smoke [Reference Robin29].

The influenza mortality disparity between AI/AN persons and the general population is a challenge for influenza preparedness [Reference Groom30]. Prior to 2009, AI/AN individuals were not prioritized to receive vaccine or antiviral medications on the basis of racial status in the United States. However, recommendations now include AI/AN persons as a high-risk group [31, 32]. Some might consider that a risk factor-based strategy would be sufficient to identify AI/AN persons at risk for influenza complications. However, using the criteria for receipt of antiviral medications, 30% of fatal AI/AN cases would not have been considered high risk. By contrast, only 16% of influenza fatalities in whites would not have been considered high risk. AI/AN persons during 2009 also suffered disproportionately from influenza illness, hospitalizations and intensive care unit admissions. This is similar to the experience of AI/AN persons throughout the past two decades [Reference Groom33]. Thus, a risk factor-based strategy may not be comprehensive enough to address these long-standing influenza disparities. Designating AI/AN persons as high-risk can allow a more rapid delivery of vaccine, antiviral medications and education through the US Indian Health Service, tribal and urban Indian clinics. Thus, maintaining the high-risk designation may be more likely to reduce the health disparity than a risk factor-based approach.

Influenza immunization uptake in AI/AN persons is similar to the general United States population, but should be improved [34, Reference Lindley35]. Efforts to reduce smoking prevalence and obesity in AI/AN persons may be beneficial in reducing influenza mortality. Smoking prevalence in AI/AN adults (31·4%) far exceeds the overall US population (19·0%) [36]. Likewise, obesity in AI/AN adults (39·6% prevalence) is more common that in non-Hispanic whites (26%) [37].

These findings may not be generalizable to the entire United States or to all AI/AN persons. Because controls had access to healthcare and telephone service, comparisons for related socioeconomic factors may have been limited by design. By modelling only three age groups our ability to detect gradations in risk within age groups is limited. Missing data was addressed through multiple imputation which improved the power but would not solve potential bias related to representativeness of the population. We may have underestimated the number of AI/AN persons in the fatalities, since misclassification of AI/AN decedents has been documented [Reference Arias38]. Since approval was not obtained from all Arizona tribes, there was systematic under-recruitment of AI/AN persons and reduced representativeness of the included cases. Glucocorticoids used as a fever-reducing agent was identified as a risk factor for influenza death in China [Reference Han39]. This is not a recommended practice in the United States [40]. However, because we did not obtain the timing or dosage of corticosteroid administration and nearly 50% of the fatal cases had received steroids, this remains a potential, uncontrolled confounder.

During the 2009 pandemic, AI/AN racial status was not independently associated with death, but was a marker for other modifiable factors. Keeping AI/AN race in the high-risk conditions for influenza complications should be considered as an appropriate response to the elevated risk of morbidity and mortality in this population. Increased efforts to reduce influenza mortality are needed to address this longstanding health disparity.

APPENDIX. Investigative Team

Alaska: Steve Bentley, James Keck, Sassa Kitka, Gail Thompson, Donna Fearey, Diana Redwood, Jessica Craig, Ellen Provost. Arizona: Keisha Robinson. New Mexico: Rhonda Noble. Oklahoma: Laurence Burnsed, Kendra Dougherty, Anthony Lee, Christie McDonald-Hamm, Laura Smithee, Jean Williams. Wyoming: Reginald McClinton. Council of State and Territorial Epidemiologists: Annie Tran. Indian Health Service: John Redd, James Cheek. CDC: Ralph Bryan, Michael Jhung. Other US States: Nato Tarkhashvili (South Dakota), Richard Danila (Minnesota), Richard Leman (Oregon), Eden Wells (Michigan), Kathy Lofy (Washington), Tracy Miller (North Dakota).

ACKNOWLEDGEMENTS

Alaska: Jeremy Wood, Greg Raczniak, Michele Toomey. Arizona: Sara Imholte, John Meyer, Steve Baty, Anita Thorne, Zeenat Mahal, Sibeso Joyner, Eva Torres, Erica Weis, Justin Weddle, Tina Szopinski-Rubin, Reva Litt, Amritha Panachanathan. Oklahoma: Alfred Aiyanyor, Rachel Clinton, Margaret Selby. Wyoming: Tracy Murphy, Clayton Van Houten. Council of State and Territorial Epidemiologists: Edward Chao, Jennifer Lemmings, Monica Huang. Other states: Melissa Powell (OR), Lon Kightlinger (SD), Rachelle Boulton (UT), Anthony Marfin (WA), Megan Hoopes (NPAIHB), Thomas Kim (CTEC), John Mosely Hayes (USETI), Thomas Weiser (NPAIHB), Lindsey VanderBusch (ND), Steven Helgersen (MT), Folorunso Akintan (RMTEC), Rachel Herlihy (UT), Ruta Sharangpani (MI), Jennie Finks (MI), Catherine Lexau (MN), Craig Morin (MN), Aaron DeVries (MN), Melissa Morrison (AL/CDC). CDC: Alicia Fry, Scott Santibanez, Jay Wenger.

Funding support was contributed by the Council of State and Territorial Epidemiologists (Cooperative Agreement Number 1U38HM000414 from CDC), plus in-kind contributions by CDC, state health departments and tribal epidemiology centers.

The findings and conclusions in this publication are those of the authors and do not necessarily represent the official views of the U.S. Centers for Disease Control and Prevention (CDC) or the Indian Health Service.

DECLARATION OF INTEREST

None.

References

REFERENCES

1. Dee, DL, et al. Racial and ethnic disparities in hospitalizations and deaths associated with 2009 pandemic influenza (H1N1) virus infection in the United States. Annals of Epidemiology 2011; 623–630 CrossRef Google Scholar PubMed

2. Wenger, JD, et al. 2009 pandemic influenza A H1N1 in Alaska: temporal and geographic characteristics of spread and increased risk of hospitalization among Alaska Native and Asian/Pacific Islander people. Clinical Infectious Disease 2011; 52: S189–S197.Google Scholar

3. Chowell, G, et al. Risk factors for mortality among 2009A/H1N1 influenza hospitalizations in Maricopa County, Arizona, April 2009 to March 2010. Computational and Mathematical Methods in Medicine 2012; 2012: 914196.CrossRef Google Scholar

4. Thompson, DL, et al. Risk factors for 2009 pandemic influenza A(H1N1)-related hospitalization and death among racial/ethnic groups in New Mexico. American Journal of Public Health 2011; 101: 1776–1784.Google Scholar

5. Kumar, A, et al. Critically ill patients with 2099 influenza A (H1N1) infection in Canada. Journal of the American Medical Association 2009; 302: 1872Google Scholar

6. Zarychanksi, R, et al. Correlates of severe disease in patients with 2009 pandemic influenza (H1N1) virus infection. Canadian Medical Association Journal 2010; 10: 257–264.CrossRef Google Scholar

7. CDC. Deaths related to 2009 pandemic influenza A (P-) among American Indian/Alaska Natives – 12 states, 2009. Morbidity and Mortality Weekly Report 2009; 58: 1341–1344 Google Scholar

8. Blake, K, Kellerson, R, Simic, A. Measuring overcrowding in housing. Washington, DC: Department of Housing and Urban Development, Office of Policy Development and Research, 2007.Google Scholar

9. Allison, PD. Missing Data. Series: Quantitative Application in the Social Sciences, volume 136. Thousand Oaks, CA: Sage Publications, 2001.Google Scholar

10. Bernaards, CA, Belin, TR, Schafer, JL. Robustness of a multivariate normal approximation for imputation of incomplete binary data. Statistics in Medicine 2007: 26: 1368–1382.CrossRef Google Scholar PubMed

11. Lee, KJ, Carlin, JB. Multiple imputation for missing data: fully conditional specification versus multivariate normal imputation. American Journal of Epidemiology 2010; 171: 624–632.Google Scholar

12. Graham, JW, Alchowski, AE, Gilreath, TD. How many imputations are really needed? Some practical clarification of multiple imputation theory. Prevention Science 2007; 8: 206–213.CrossRef Google Scholar PubMed

13. Yuan, Y. Multiple imputation using SAS software. Journal of Statistical Software 2011; 45: 1–25.Google Scholar

14. Hosmer, DW, Lemeshow, S. Applied Logistic Regression, 2nd edn. New York: John Wiley & Sons, 2000.Google Scholar

15. Wood, AM, White, IR, Royston, P. How should variable selection be performed with multiply imputed data? Statistics in Medicine 2008; 27: 3227–3246.CrossRef Google Scholar PubMed

16. Epstein, MA, Reynaldo, S, Nelson El-Amin, A. Is smoking a risk factor for influenza hospitalization and death? Journal of Infectious Diseases 2010; 201: 794–795.Google Scholar

17. Regan, J, et al. Epidemiology of influenza A(H1N1)pdm09-associated deaths in the United States, September-October 2009. Influenza 2012; 6: e169–177.Google Scholar

18. Fowlkes, AL, et al. Epidemiology of 2009 pandemic influenza A (H1N1) death in the United States, April-July 2009. Clinical Infectious Disease 2011 (Suppl. 1): S60–68.Google Scholar

19. Morgan, OW, et al. Morbid obesity as a risk factor for hospitalization and death due to 2009 pandemic influenza A(H1N1) disease, PLoS ONE 2010; 5: e9694.CrossRef Google Scholar PubMed

20. Zarychanski, R, et al. Correlates of severe disease in patients with 2009 pandemic influenza (H1N1) virus infection. Canadian Medical Association Journal 2010; 182: 257–264.CrossRef Google Scholar PubMed

21. Kumar, A, Zarychanski, R, Pinto, R. Critically ill patients with 2009 influenza A(H1N1)infection in Canada. Journal of the American Medical Association 2009; 302: 1872–9.Google Scholar

22. CDC. Selected indicators for states, 2012 (http://www.cdc.gov/tobacco/data_statistics/state_data/state_highlights/2012/pdfs/indicators.pdf). Accessed 24 June 2013 Google Scholar

23. Jones, DS, The persistence of American Indian health disparities. American Journal of Public Health 2006; 96: 2122–2134.Google Scholar

24. Bulkow, LR, et al. Risk factors for hospitalization with lower respiratory tract infection in children in rural Alaska. Pediatrics 2012; 129: e1220–1227.Google Scholar

25. Singleton, RJ, et al. Viral respiratory infection in hospitalized and community control children in Alaska. Journal of Medical Virology 2010; 82: 1282–1290.CrossRef Google Scholar PubMed

26. Hennessy, TW, et al. The relationship between in-home water service and the risk of respiratory tract, skin, and gastrointestinal tract infections among rural Alaska Natives. American Journal of Public Health 2008; 98: 2072–2078.Google Scholar

27. Gessner, BD, Lack of piped water and sewage services is associated with pediatric lower respiratory tract infection in Alaska. Journal of Pediatrics 2008; 152: 666–700.Google Scholar

28. Wenger, JD, et al. Invasive pneumococcal disease in Alaskan children: impact of the seven-valent pneumococcal conjugate vaccine and the role of water supply. Pediatric Infectious Disease Journal 2010; 29: 251–256.Google Scholar

29. Robin, LF, et al. Wood-burning stoves and lower respiratory illnesses in Navajo children. Pediatric Infectious Disease Journal 1996; 15: 859–865.Google Scholar

30. Groom, AV, et al. Pandemic influenza preparedness and vulnerable populations in tribal communities. American Journal of Public Health 2009; 9b9: S271–278.Google Scholar

31. CDC. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010 (http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5908a1.htm?s_cid=rr5908a1_w). Accessed 24 June 2013.Google Scholar

32. CDC. Antiviral agents for the treatment and chemoprophylaxis of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP) (http://www.cdc.gov/mmwr/preview/mmwrhtml/rr6001a1.htm). Accessed 24 June 2013.Google Scholar

33. Groom, AV, et al. Pneumonia and influenza mortality among American Indian and Alaska Native people, 1990–2009. American Journal of Public Health 2014; 104: S460–469.Google Scholar

34. CDC. Seasonal influenza vaccination coverage – United States, 2009–10 and 2010–11 Morbidity and Mortality Weekly Reports 2013; 62: 65–68 Google Scholar

35. Lindley, MC, et al. Population status of influenza and pneumococcal vaccination among older American Indians and Alaska Natives. American Journal of Public Health 2008; 98: 932–938.Google Scholar

36. CDC. Adult cigarette smoking in the United States 2010 (http://www.cdc.gov/tobacco/data_statistics/fact_sheets/adult_data/cig_smoking/). Accessed 24 June 2013.Google Scholar

37. CDC. Summary health statistics for U.S. adults: National Health Interview Survey, 2010 (http://www.cdc.gov/nchs/data/series/sr_10/sr10_252.pdf). Accessed 24 June 2013.Google Scholar

38. Arias, E, et al. The validity of race and Hispanic origin reporting on death certificates in the United States. Vital and Health Statistics 2008 (series 2), no. 148.Google Scholar

39. Han, K, et al. Early use of glucocorticoids was a risk factor for crucial disease and death from pH1N1 infection. Clinical Infectious Diseases 2011; 53: 326–333.Google Scholar

40. CDC. Interim information for clinicians about human infections with H3N2v virus (http://www.cdc.gov/flu/swineflu/h3n2v-clinician.htm). Accessed 10 April 2015.Google Scholar

Fig. 1. Fatal influenza cases by week of death, 2009, for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming) and overall United States.

Table 1. Characteristics of participants, influenza mortality investigation for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

Table 2. Univariate risk factors for death due to H1N1 in a matched case-control investigation, five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

Table 3. Risks factors for influenza mortality, multivariable results for matched case-control investigation, for five states (Alaska, Arizona, New Mexico, Oklahoma, Wyoming), 2009

Crossref Citations

This article has been cited by the following publications. This list is generated based on data provided by Crossref.

Grohskopf, Lisa A. Sokolow, Leslie Z. Broder, Karen R. Olsen, Sonja J. Karron, Ruth A. Jernigan, Daniel B. and Bresee, Joseph S. 2016. Prevention and Control of Seasonal Influenza with Vaccines. MMWR. Recommendations and Reports, Vol. 65, Issue. 5, p. 1.

McLeod, C Adunuri, N and Booth, R 2019. Risk factors and mitigation of influenza among Indigenous children in Australia, Canada, United States, and New Zealand: a scoping review. Perspectives in Public Health, Vol. 139, Issue. 5, p. 228.

Shen, Angela K. Groom, Amy V. Leach, Diane L. Bridges, Carolyn B. Tsai, Alice Y. and Tan, Litjen 2019. A pathway to developing and testing quality measures aimed at improving adult vaccination rates in the United States. Vaccine, Vol. 37, Issue. 10, p. 1277.

Han, Lefei Ran, Jinjun Mak, Yim-Wah Suen, Lorna Kwai-Ping Lee, Paul H. Peiris, Joseph Sriyal Malik and Yang, Lin 2019. Smoking and Influenza-associated Morbidity and Mortality. Epidemiology, Vol. 30, Issue. 3, p. 405.

Chen, Liang Han, Xiudi Li, Yan Li Zhang, Chunxiao and Xing, Xiqian 2020. FluA-p score: a novel prediction rule for mortality in influenza A-related pneumonia patients. Respiratory Research, Vol. 21, Issue. 1,

Arrazola, Jessica Masiello, Matthew M. Joshi, Sujata Dominguez, Adrian E. Poel, Amy Wilkie, Crisandra M. Bressler, Jonathan M. McLaughlin, Joseph Kraszewski, Jennifer Komatsu, Kenneth K. Peterson Pompa, Xandy Jespersen, Megan Richardson, Gillian Lehnertz, Nicholas LeMaster, Pamela Rust, Britney Keyser Metobo, Alison Doman, Brooke Casey, David Kumar, Jessica Rowell, Alyssa L. Miller, Tracy K. Mannell, Mike Naqvi, Ozair Wendelboe, Aaron M. Leman, Richard Clayton, Joshua L. Barbeau, Bree Rice, Samantha K. Warren-Mears, Victoria Echo-Hawk, Abigail Apostolou, Andria and Landen, Michael 2020. COVID-19 Mortality Among American Indian and Alaska Native Persons — 14 States, January–June 2020. MMWR. Morbidity and Mortality Weekly Report, Vol. 69, Issue. 49, p. 1853.

Mamelund, Svenn-Erik Shelley-Egan, Clare Rogeberg, Ole and Ekwunife, Obinna Ikechukwu 2021. The association between socioeconomic status and pandemic influenza: Systematic review and meta-analysis. PLOS ONE, Vol. 16, Issue. 9, p. e0244346.

2021. Recommendations for Prevention and Control of Influenza in Children, 2021–2022. Pediatrics, Vol. 148, Issue. 4,

Perkins, Douglas J Yingling, Alexandra V Cheng, Qiuying Castillo, Amber Martinez, Janae Bradfute, Steven B Leng, Shuguang Edwards, Jeremy Guo, Yan Mertz, Gregory Harkins, Michelle Unruh, Mark Worsham, Anthony Lambert, Christophe G Teixeira, J Pedro Seidenberg, Phillip Langsjoen, Jens Schneider, Kristan and Hurwitz, Ivy 2022. Elevated SARS-CoV-2 in peripheral blood and increased COVID-19 severity in American Indians/Alaska Natives. Experimental Biology and Medicine, Vol. 247, Issue. 14, p. 1253.

Luo, Jessica Rosales, Megan Wei, Guo Stoddard, Gregory J Kwok, Alvin C Jeyapalina, Sujee and Agarwal, Jayant P 2022. Hospitalization, mechanical ventilation, and case-fatality outcomes in US veterans with COVID-19 disease between years 2020–2021. Annals of Epidemiology, Vol. 70, Issue. , p. 37.

Kondo, Karli K. Williams, Beth E. Ayers, Chelsea K. Kansagara, Devan Smith, Mia Advani, Shailesh M. Young, Sarah and Saha, Somnath 2022. Factors Associated with Health Inequalities in Infectious Disease Pandemics Predating COVID-19 in the United States: A Systematic Review. Health Equity, Vol. 6, Issue. 1, p. 254.

Lee, Naomi R King, Alexandra Vigil, Deionna Mullaney, Dustin Sanderson, Priscilla R Ametepee, Taiwo and Hammitt, Laura L 2023. Infectious diseases in Indigenous populations in North America: learning from the past to create a more equitable future. The Lancet Infectious Diseases, Vol. 23, Issue. 10, p. e431.

van Doren, Taylor P. Zajdman, Deborah Brown, Ryan A. Gandhi, Priya Heintz, Ron Busch, Lisa Simmons, Callie and Paddock, Raymond 2023. Risk perception, adaptation, and resilience during the COVID-19 pandemic in Southeast Alaska Natives. Social Science & Medicine, Vol. 317, Issue. , p. 115609.

Theodore, Deborah A. Branche, Angela R. Zhang, Lily Graciaa, Daniel S. Choudhary, Madhu Hatlen, Timothy J. Osman, Raadhiya Babu, Tara M. Robinson, Samuel T. Gilbert, Peter B. Follmann, Dean Janes, Holly Kublin, James G. Baden, Lindsey R. Goepfert, Paul Gray, Glenda E. Grinsztejn, Beatriz Kotloff, Karen L. Gay, Cynthia L. Leav, Brett Miller, Jacqueline Hirsch, Ian Sadoff, Jerald Dunkle, Lisa M. Neuzil, Kathleen M. Corey, Lawrence Falsey, Ann R. El Sahly, Hana M. Sobieszczyk, Magdalena E. Huang, Yunda Adams, Atoya Miller, Eric Rankin, Bruce G. Shinn, Steven Nash, Marshall Green, Sinikka L. Jacobsen, Colleen Krishnankutty, Jayasree Phungwayo, Sikhongi Glover, Richard M. Slechta, Stacy Holdeman, Troy Hartvickson, Robyn Grant, Amber Poling, Terry L. Klein, Terry D. Klein, Thomas C. Klein, Tracy R. Smith, William B. Gibson, Richard L. Winbigler, Jennifer Parker, Elizabeth Wijewardane, Priyantha N. Bravo, Eric Thessing, Jeffrey Maxwell, Michelle Horn, Amanda Mary Healy, Catherine Akamine, Christine Chu, Laurence Chouteau, R. Michelle Cotugno, Michael J. Bauer, George H. Hachigian, Greg Oshita, Masaru Cancilla, Michael Kiersey, Kristen Seger, William Antwi, Mohammed Green, Allison Kim, Anthony Desjardins, Michael Johnson, Jennifer A. Sherman, Amy Walsh, Stephen R. Borger, Judith Saleem, Nafisa Solis, Joel Carmen Medina, Martha Keating, Westly Garcia, Edgar Bueno, Cynthia Segall, Nathan Denham, Douglas S. Weiss, Thomas Avworo, Ayoade Hedges, Parke Becher Strout, Cynthia Santiago, Rica Davis, Yvonne Howenstine, Patty Bondell, Alison Marks, Kristin Wang, Tina Wilkin, Timothy Vogler, Mary Johnston, Carrie Andrasik, Michele P. Andriesen, Jessica G. Broder, Gail Eaton, Niles Gelderblom, Huub G. McClennen, Rachael Michael, Nelson Robb, Merlin Sopher, Carrie Miller, Vicki E. Santiago, Fredric Gomez, Blanca Valika, Insiya Starr, Amy Cantos, Valeria D. Kandiah, Sheetal del Rio, Carlos Rouphael, Nadine Edupuganti, Srilatha Anderson, Evan J. Camacho-Gonzalez, Andres Kamidani, Satoshi Rostad, Christiana A. Teherani, Meghan Diemert, David J. Malkin, Elissa Siegel, Marc Roberts, Afsoon Simon, Gary Balani, Bindu Stephenson, Carolene Sperber, Steven Cicogna, Cristina Zervos, Marcus J. Kilgore, Paul Ramesh, Mayur Herc, Erica Zenlea, Kate Burgher, Abram Milliken, Ann M. Davis, Joseph D. Levy, Brendan Kelman, Sandra Doust, Matthew W. Sample, Denise Erickson, Sandra Christensen, Shane G. Matich, Christopher Longe, James Witbeck, John Peterson, James T. Clark, Alexander Kelty, Gerald Pena-Renteria, Issac Koren, Michael J. Bartilucci, Darlene Patel, Alpa Tran, Carolyn Kennelly, Christina Brownlee, Robert Coleman, Jacob Webster, Hala Fierro, Carlos A. Leistner, Natalia Thompson, Amy Gonzalez, Celia Jackson, Lisa A Suyehira, Janice Haber, Milton Regalado, Maria M. Procasky, Veronica Lutat, Alisha Griffin, Carl P. Hollister, Ripley R. Brown, Jeremy Ronk, Melody Harper, Wayne L. Cohen, Lisa Eckert, Lynn Hong, Matthew Rouhbakhsh, Rambod Danford, Elizabeth Johnson, John Calderone, Richard Khetan, Shishir K. Olanrewaju, Oyebisi Zhai, Nan Nieves, Kimberly O'Brien, Allison Bradley, Paul S Lilienthal, Amanda Callis, Jim Brosz, Adam B Clement, Andrea West, Whitney Friesen, Luke Cramer, Paul Eder, Frank S Little, Ryan Engler, Victoria Rattenbury-Shaw, Heather Ensz, David J. Oplinger, Allie Essink, Brandon J. Meyer, Jay Raiser, Frederick Mueller, Kimberly Vrbicky, Keith W. Harper, Charles Nutsch, Chelsie Lewis, Wendell Laflan, Cathy Whatley, Jordan L. Harrell, Nicole Shannon, Amie Rowell, Crystal Dedon, Christopher Makhene, Mamodikoe Gottschlich, Gregory M. Harden, Kate Gottschlich, Melissa Smith, Mary Powell, Richard Kimmel, Murray A. Pinto, Simmy Vachris, Timothy P. Hutchens, Mark Daniels, Stephen Wells, Margaret Van Der Leden, Mimi Jackson-Booth, Peta-Gay Baron, Mira Kane, Pamela Seversen, Shannen Kryvicky, Mara Lord, Julia Saleh, Jamshid Miles, Matthew Lupercio, Rafael McGettigan, John W. Patton, Walter Brakema, Riemke Choquette, Karin McGettigan, Jonlyn Kirstein, Judith L. Bernard, Marcia Manning, Mary Beth Rothenberg, Joan Briskin, Toby Roadman, Denise Tedder-Edwards, Sharita Schwartz, Howard I. Mederos, Surisday Swaminathan, Shobha Nyaku, Amesika Varughese, Tilly DallaPiazza, Michelle Frey, Sharon E. Graham, Irene Abate, Getahun Hoft, Daniel Allen, Leland N. Edwards, Leslie A. Davis, William S. Mena, Jessica M. Kutner, Mark E. Caso, Jorge Hernandez Moran, Maria Carvajal, Marianela Mendez, Janet Wadsworth, Larkin T. Adams, Michael R. Iverson, Leslie Newberg, Joseph L. Pearlman, Laura Nugent, Paul J. Reynolds, Michele D. Bashour, Jennifer Schmidt, Robert Sheth, Neil P. Steil, Kenneth Toma, Ramy J. Kirby, William Folmar, Pink Williams, Samantha Pickrell, Paul Mott, Stefanie Linebarger, Carol Ann Malbari, Hussain Pampe, David Fragoso, Veronica G. Holloway, Lisa McKeown-Bragas, Cecilia Becker, Teresa Williams, Barton G. Jones, William H. Clark, Jesse L. Shoptaw, Steven Vertucci, Michele Hernandez, Will Spector, Stephen A. Moodley, Amaran Blumenthal, Jill Stangl, Lisa Deutsch, Karen Mullane, Kathleen M. Pitrak, David Nuss, Cheryl Pi, Judy Fichtenbaum, Carl Powers-Fletcher, Margaret Saemann, Michelle Kohrs, Sharon Campbell, Thomas B. Lauria, Andrew Mancilla, Jose C. Dunlevy, Hillary Novak, Richard M. Wendrow, Andrea Borgetti, Scott Ladner, Ben Laurens, Matthew Chrisley, Lisa Young, Cheryl Doblecki-Lewis, Susanne Alcaide, Maria L. Gonzales-Zamora, Jose Morris, Stephen Wohl, David Eron, Joseph Frank, Ian Dunbar, Debora Metzger, David Momplaisir, Florence Martin, Judith Hoberman, Alejandro Shope, Timothy Muniz, Gysella Rupp, Richard Stanford, Amber Berman, Megan Porterfield, Laura Lewis, Michael Ghadishah, Elham Yusin, Joseph Pham, Mai Creech, Clarence B. Walker, Shannon Rolsma, Stephanie Samuels, Robert Thomsen, Isaac Kalams, Spyros A. Wilson, Greg Lucksinger, Gregg H. Parks, Kevin Israelsen, Ryan Ostovar, Jaleh Kelly, Kary Overcash, Jeffrey S. Chu, Hanh Lee, Kia De La Cruz, Luis I. Clemons, Steve Everette, Elizabeth Studdard, Suzanna Mohan, Gowdhami Tyson, Stefanie Peay, Alyssa-Kay Johnson, Danyel Feldman, Gregory J. Suen, May-Yin Muenzner, Jacqueline Boscia, Joseph Siddiqui, Farhan Sanders, John Peacock, James Nasim, Julio Levin, Michael L. Hussey, Julie Kulic, Marcy McKenzie, Mark M. Deese, Teresa Osmundsen, Erica Sweet, Christy Ebuh, Valentine M. Elnagar, Elwaleed Ebuh, Georgette Iwuala, Genevieve Han-Conrad, Laurie J. Simmons, Todd Tarakjian, Denis Ackermann, Jeremy Adams, Mark S. Alemán, José O. Al-Ibrahim, Mohamed S. Andes, David R. Andrews, Jeb Arduino, Roberto C. Bäcker, Martín Badillo, Diana Bainbridge, Emma Batteiger, Teresa A. Bazan, Jose A. Bedimo, Roger J. Benitez, Jorge A. Bennett, Annette R. Bernstein, David I. Bialobok, Kristin Boas, Rebecca Brady, Judith Brown, Cynthia Bunce, Catherine A. Call, Robert S. Campbell, Wesley Carmody, Ellie Carpenter, Christopher Carsons, Steven E. Castellon, Marvin Castro, Mario Catan, Hannah Chang, Jennifer Chebib, Mouna G. Chen, Corey M. Cheng, Margaret Chow, Brian D. W. Ciambruschini, Annie Connor, Joseph P. Conway, James H. Cooney, Maureen Curlin, Marcel De La Matta Rodriguez, Claudia Dedon, Jon F. Degan, Emily Dickey, Michelle Dietz, Craig Dong, Jennifer L Dorcely, Brenda Dube, Michael P. Dyer, Carmel B. Eckhardt, Benjamin Ellerbeck, Edward Ewers, Evan C. Falk, Amy Feijoo, Brittany Felsen, Uriel R. Fiel, Tom Fitz-Patrick, David Fogarty, Charles M. Ford, Stacy Forero, Lina M. Formentini, Elizabeth Franco-Vitteri, Doris Frenck, Robert W. Gharib, Elie Gharib, Suzanne Rucker, Rola G. Goldenberg, James N. González, Luis H. Gray, Brett Greene, Rusty Grossberg, Robert M. Guanira-Carranza, Juan V. Gilberto Guerreros Benavides, Alfredo Guillory, Clint C. Gunaratne, Shauna H. Halpert, David Hamilton, Holli Hartman, William R. Henderson, Sheryl L. Herati, Ramin Hernandez Guarin, Laura Hilder, Robin Ho, Ken Hojat, Leila Hosek, Sybil G. Jacobson, Jeffrey M. Jay, Melanie Johnson, Diane H. Jones, Kathleen S. Jones-López, Edward C. Justman, Jessica E. Kahney, Scott Katz, Lois Katz, Melinda Kaul, Daniel Keefer, Michael C. Kennedy, Ashley Knishinsky, Jennifer Kogelman, Laura Koletar, Susan L. Kottkamp, Angelica Laguio-Vila, Maryrose Landovitz, Raphael J. Lee, Jessica L. Liu, Albert Giuvanela Llerena Zegarra, Eneyda Lok, Anna S. Lovell, James Lubelchek, Ronald Lucaj, John Luckasen, Gary Luetkemeyer, Annie Lucia Lugogo, Njira Maenza, Janine Malvestutto, Carlos Mauri, Monica Maves, Ryan C. Mayer, Kenneth H. McCartney, Michael J. McCort, Margaret E. McElrath, M. Juliana McNairy, Meredith Merino, Fernando L. Meyerowitz, Eric A. Mitchell, Carol L. Monaco, Cynthia L. Muhammad, Sauda Muñoz-Gómez, Sigridh Munsiff, Sonal Nee, Paul Nollen, Nicole L. Noor, Asif Nuñez Lagos, Claudio Okulicz, Jason F. Oliver, Patrick A. Ortega, Jessica Palmer, Steven Parameswaran, Lalitha Parikh, Purvi Parker, Susan Parungao, Reza Pavie, Juana R. Madan, Rebecca P. Peralta, Henry Petts, Jennifer Pierce, Kristen K. Pretell Alva, E. Javier Purpura, Lawrence J. Raabe, Vanessa Recuenco, Sergio E. Richards, Tamara Riddler, Sharon A. Rizzardi, Barbara Rokser, Rachel Rolle, Charlotte-Paige Rosen, Adam Rosen, Jeffrey Freese, Lena R. Santolaya, María E. Schipani, Linda M. Schwartz, Adam Schwasinger-Schmidt, Tiffany Scott, Hyman Sha, Beverly E. Shankaran, Shivanjali Shapiro, Adrienne E. Sharp, Stephan C. Shopsin, Bo Sims, Matthew D. Skipper, Stephanie Smith, Derek M. Smith, Michael J. Sobhanie, M. Mahdee Sovic, Brit Sterling, Stephanie Striker, Robert Tafur Bances, Karla Beatriz Talaat, Kawsar R. Tavel, Edward M. Tieu, Hong V Tomaszewski, Christian Tomlinson, Ryan Torres, Juan P. Torres, Julian A. Treanor, John J Tukuru, Sade Ulrich, Robert J. Utz, Gregory C. Viar, Veronica Viau Colindres, Roberto A. Walsh, Edward E. Walsh, Mary C. Walter, Emmanuel B. Weidler, Jessica L. Wu, Yi H. Yang, Kinara S. Yrivarren Giorza, Juan Luis Zemanek, Arthur L. Zhang, Kevin Zingman, Barry S. Gorman, Richard Paez, Carmen A. Swann, Edith Takuva, Simbarashe G. Greninger, Alex Roychoudhury, Pavitra Coombs, Robert W. Jerome, Keith R. Castellino, Flora Tong, Xiaomi Pavetto, Corrina Gipson, Teletha Tong, Tina Lee, Marina Zhou, James Fay, Michael McQuarrie, Kelly Nnadi, Chimeremma Sogbetun, Obiageli Ahmad, Nina De Proost, Ian Hoseyni, Cyrus Coplan, Paul Khan, Najat Ronco, Peter Furey, Dawn Meck, Jodi Vingerhoets, Johan Brandenburg, Boerries Custers, Jerome Hendriks, Jenny Juraszek, Jarek de Groot, Anne Marit Van Roey, Griet Heerwegh, Dirk Van Dromme, Ilse Méndez Galván, Jorge F. Carrascal, Monica B. Sordo Duran, Adriana Sanchez Guerrero, Laura Ruy Gómora Madrid, Martha Cecilia Barrat Hernández, Alejandro Quintín Molina Guizar, Sharzhaad González Estrada, Denisse Alejandra Martínez Pérez, Silvano Omar Zárate Hinojosa, Zindy Yazmín Ruiz-Palacios, Guillermo Miguel Cruz-Valdez, Aurelio Pacheco-Flores, Janeth Lara, Anyela Díaz-Miralrio, Secia Reyes Fentanes, María José Olmos Vega, Jocelyn Zuleica Pineda Méndez, Daniela Cano Martínez, Karina Alvarez León, Winniberg Stephany Ruiz Herrera, Vida Veronica Vázquez Saldaña, Eduardo Gabriel Camacho Choza, Laura Julia Vega Orozco, Karen Sofia Ortega Domínguez, Sandra Janeth Chacón, Jorge A. Rivera, Juan J. Cutz, Erika A. Ortegón, Maricruz E. Rivera, María I. Browder, David Burch, Cortney Moye, Terri Bondy, Paul Browder, Lesley Manning, Rickey D. Hurst, James W. Sturgeon, Rodney E. Wakefield, Paul H. Kirby, John A. Andersen, James Fearon, Szheckera Negron, Rosa Medina, Amy Hill, John M. Rajasekhar, Vivek Williams, Hayes Cade, LaShondra Fouts, Rhodna Moya, Connie Anderson, Corey G. Devine, Naomi Ramsey, James Perez, Ashley Tatelbaum, David Jacobs, Michael Menasche, Kathleen Mirkil, Vincent Winkle, Peter J. Haggag, Amina Z. Haynes, Michelle Villegas, Marysol Raja, Sabina Riesenberg, Robert Plavin, Stanford Lerman, Mark Woodside, Leana Johnson, Maria Healy, C. Mary Whitaker, Jennifer A. Keitel, Wendy A. Atmar, Robert L. Horwith, Gary Mason, Robin Johnson, Lisa Dora, Tambra Murray, Deborah Ledbetter, Logan Ewing, Beverly Stephenson, Kathryn E. Tan, Chen S. Zash, Rebecca Ansel, Jessica L. Jaegle, Kate Guiney, Caitlin J. Henderson, Jeffrey A. O'Leary, Marcia Enright, Kendra Kessler, Jill Ducheneaux, Pete Inniss, Asha Brandon, Donald M. Davis, William B. Lawler, Daniel T. Oppong, Yaa D. Starr, Ryan P. Syndergaard, Scott N. Shelly, Rozeli Islam Majumder, Mashrur Sugimoto, Danny Dugas, Jeffrey Rijos, Dolores Shelton, Sandra Hong, Stephan Schwartz, Howard Sanchez-Crespo, Nelia Schwartz, Jennifer Piedra, Terry Corral, Barbara Medina, Carmen Dever, Michael E. Shah, Mitul Delgado, Michael Scott, Tameika Usdan, Lisa S. McGill, Lora J. Arnold, Valerie K. Scatamacchia, Carolyn Anthony, Codi M. Merchant, Rajan Yoon, Anelgine C. Hill, Janet Ng-Price, Lucy Thompson-Seim, Teri Ackerman, Ronald Ackerman, Jamie Aristy, Florida Ketter, Nzeera Finley, Jon Stull, Mildred Murray, Monica Rizvi, Zainab Guerrero, Sonia Paliwal, Yogesh K. Paliwal, Amit Gordon, Sarah Gordon, Bryan Montano-Pereira, Cynthia Galloway, Christopher Montros, Candice Aleman, Lily Shairi, Samira Van Ever, Wesley Freeman, George H. Harmon, Esther L. Cross, Marshall A. Sales, Kacie Gular, Catherine Q. Hepburn, Matthew Alderson, Nathan Harshell, Shana Mahgoub, Siham Maxwell, Celia Mellman, Thomas Thompson, Karl M. Wortman, Glenn Kingsley, Jeff Pixler, April Curry, LaKondria Afework, Sarah Swanson, Austin Jacqmein, Jeffry Bowers, Maggie Robison, Dawn Mosteller, Victoria Garvey, Janet Easley, Mary Kurnat, Rebecca J. Cornelison, Raymond Gower, Shanda Schnitz, William Heinzig-Cartwright, Destiny S. Lewis, Derek Newton, Fred E. Duhart, Aeiress Watkins, Breanz Ball, Brandy York, Jill Pickle, Shelby Musante, David B. Silver, William P. Belhorn, Linda R. Viens, Nicholas A. Dellaero, David Patel, Priti Lisec, Kendra Safirstein, Beth Zapata, Luz Gonzalez, Lazaro Quevedo, Evelyn Irani, Farah Grillo, Joseph Potts, Amy White, Julie Flume, Patrick Headden, Gary Taylor, Brandie Warden, Ashley Chamberlain, Amy Jeanfreau, Robert Jeanfreau, Susan Matherne, Paul G. Caldwell, Amy Stahl, Jessica Vowell, Mandy Newhouse, Lauren Berthaud, Vladimir Takizala, Zudi-Mwak Beninati, Genevieve Snell, Kimberly Baker, Sherrie Walker, James Harrison, Tavane Miller, Meagan Otto, Janet Gray, Roni Wilson, Christine Nemecek, Tiffany Harrington, Hannah Eppenbach, Sally Lewis, Wendell Bourgeois, Tana Folsom, Lyndsea Holt, Gregory Mirsaeidi, Mehdi Calderon, Rafael Lichtenberger, Paola Quintero, Jalima Martinez, Becky Immergluck, Lilly Johnson, Erica Chan, Austin Fas, Norberto Thomas-Seaton, LaTeshia Khizer, Saadia Staben, Jonathan Beresnev, Tatiana Jahromi, Maryam Marovich, Mary A. Hutter, Julia Nason, Martha Ledgerwood, Julie Mascola, John Leibowitz, Mark Morales, Fernanda Delgado, Mike Sanchez, Rosario Vega, Norma Áñez, Germán Albert, Gary Coston, Erin Desai, Chinar Dunbar, Haoua Eickhoff, Mark Garcia, Jenina Kautz, Margaret Lee, Angela Lewis, Maggie McGarry, Alice McKnight, Irene Nelson, Joy Newingham, Patrick Price-Abbott, Patty Reed, Patty Vegas, Diana Wilkinson, Bethanie Smith, Katherine Woo, Wayne Cho, Iksung Glenn, Gregory M. Dubovsky, Filip Fried, David L. Haughey, Lynne A. Stanton, Ariana C. Stevens Rameaka, Lisa Rosenberg, David Tomatsu, Lee Gonzalez, Viviana Manalo, Millie Grunstra, Bernard Quinn, Donald Claybrook, Phillip Olds, Shelby Dye, Amy Cannon, Kevin D. Chadwick, Mesha M. Jordan, Bailey Hussey, Morgan Nevarez, Hannah Kelley, Colleen F. Chung, Michael Moran, Caitlin Rebolledo, Paulina Bacher, Christina Barranco-Santana, Elizabeth Rodriguez, Jessica Mendoza, Rafael Ruperto, Karen Olivieri, Odette Ocaña, Enrique Wylie, Paul E. Henderson, Renea Jenson, Natasa Yang, Fan Kelley, Amy Finkelstein, Kenneth Beckmann, David Hutchins, Tanya Garcia Escallon, Sebastian Johnson, Kristen Sligh, Teresa S. Desai, Parul Huynh, Vincent Lopez, Carlos Mendoza, Erika Adelglass, Jeffrey Naifeh, Jerome G. Kucera, Kristine J. Chughtai, Waseem Jaffer, Shireen H. Davis, Matthew G. Foley, Jennifer Burgett, Michelle L. Shlotzhauer, Tammi L. Ingalsbe-Geno, Sarah M. Duncanson, Daniel Kush, Kelly Nesbitt, Lori Sonnier, Cora McCarter, Jennifer Butcher, Michael B. Fry, James Percy, Donna Freudemann, Karen Gebhardt, Bruce C. Mangu, Padma N. Schroeck, Debra B. Davit, Rajesh K. Hennekes, Gayle D. Luft, Benjamin J. Carr, Melissa Nachman, Sharon Pellecchia, Alison Smith, Candace Valenti, Bruno Bermudez, Maria I. Peraita, Noris Delgado, Ernesto Arrazcaeta, Alicia Ramirez, Natalie Amador, Carmen Marafioti, Horacio Dang, Lyly Clement, Lauren Berry, Jennifer Allaw, Mohammed Geuss, Georgettea Miles, Chelsea Bittner, Zachary Werne, Melody Calinescu, Cornell Rodman, Shannon Rindt, Joshua Cooksey, Erin Harrison, Kristina Cooper, Deanna Horton, Manisha Philyaw, Amanda Jennings, William Alvarado, Hilario Baka, Michele Regalado, Malina Murray, Linda Naguib, Sherif Singletary, Justin Richmond, Sha-Wanda Omodele, Sarah Oppenheim, Emily Martinez, Reuben Andriulis, Victoria Singer, Leonard Blevins, Jeanne Thomas, Meagan Hull, Christine Pereira, Isabel Rivero, Gina Okonya, Tracy Downing, Frances Miller, Paulina Rhee, Margaret Stapleton, Katherine Klein, Jeffrey Hong, Rosamond Swan, Suzanne Wahlin, Tami Bennett, Elizabeth Salzl, Amy Phan, Sharine White, Jewel J. Occhino, Amanda Paiano, Ruth McLaughlin, Morgan Swieboda, Elisa Garcia-Fragoso, Veronica Becerra, Maria G. White, Toni Turley, Christine B. McWilliams, Andrew Esinhart, Tiffany Montoya, Natasha Huskey, Shamika Paul, Leena Tashima, Karen Johnson, Jennie Neill, Marguerite Sanchez, Martha Rybak, Natasha Mileno, Maria Cohen, Stuart H. Ruiz, Monica Boswell, Dean M. Robison, Elizabeth E. Reynolds, Trina L. Neumeister, Sonja Zorrilla, Carmen D. Rivera, Juana Ibarra, Jessica García, Iris Sierra, Dianca Ramon, Wanda Fiorillo, Suzanne Pitotti, Rebecca Anderson, Victoria R. Castillo Mancilla, Jose Le, Nga Winokur, Patricia L. Ince, Dilek Hegmann, Theresa Meier, Jeffrey Stapleton, Jack Stulken, Laura McArthur, Monica Berry, Andrea Tapia, Milagritos Hammershaimb, Elizabeth Robinson, Toni MacBryde, Rosa Kline, Susan Billings, Joanne L. Cavert, Winston Forgosh, Les B. Schacker, Timothy W. Bold, Tyler D. Dandachi, Dima Nelson, Taylor Bran, Andres Geiger, Grant Naqvi, S. Hasan Florescu, Diana F. Starlin, Richard Kline, David Zimmer, Andrea Abbas, Anum Wilson, Natasha Eron, Joseph J. Sciaudone, Michael Rosengren, A. Lina Kizer, John S. Rutstein, Sarah E. Rodriguez, Carina A. Bruce, Elizabeth Espinosa, Claudia Sanders, Lisa J. Kim, Kami Casey, Denise Taylor, Barbara S. Patterson, Thomas Pinilla, Ruth S. Bullock, Delia Ponce, Philip Patterson, Jan McClelland, R. Scott Lane, Dakotah C. Wald, Anna James, Frank Duke, Elizabeth Hauge, Kirsten Heimonen, Jessica Goecker, Erin A. Huang, Yunda Fong, Youyi Kauffman, Carol Linder, Kathleen Nofz, Kimberly McConnell, Andrew Buynak, Robert J. Webb, Angella Petty, Taryn Andree, Stephanie Sanchez, Erica Mackey, Nolan Baudelaire, Clarisse Dzigiel, Sarah Marquez, Adrienna Quillin, Kim King, Michelle Abad, Vanessa Knowles, Jennifer Waters, Michael Zepeda, Karla Coslet, Jordan Tovar, Dalia Shaw, Marian E. Turner, Mark A. Huffine, Cory J. Huffine, Esther S. Ake, Julie A. Secord, Elizabeth McGrath, Eric Levy, Phillip Stewart, Brittany Cromer, Charnell Walters, Ayanna Ellsworth, Grant Greene, Caroline Galloway, Sarah Kapadia, Shashi DeHaan, Elliot Wilson, Clint Milligan, Jason Raley, Danielle Bocchini, Joseph McClenathan, Bruce Hussain, Mary Lomasney, Evelyn Hall, Evelyn Lamberth, Sherry Schmeck, Christy and Leathers, Vickie 2023. Clinical and Demographic Factors Associated With COVID-19, Severe COVID-19, and SARS-CoV-2 Infection in Adults. JAMA Network Open, Vol. 6, Issue. 7, p. e2323349.

Hurwitz, Ivy Yingling, Alexandra V Amirkabirian, Teah Castillo, Amber Khan, Jehanzaeb J Do, Alexandra Lundquist, Dominic K Barnes, October Lambert, Christophe G Fieck, Annabeth Mertz, Gregory Onyango, Clinton Anyona, Samuel B Teixeira, J Pedro Harkins, Michelle Unruh, Mark Cheng, Qiuying Leng, Shuguang Seidenberg, Philip Worsham, Anthony Langsjoen, Jens O Schneider, Kristan A Perkins, Douglas J and Levine, Bruce 2023. Disproportionate impact of COVID-19 severity and mortality on hospitalized American Indian/Alaska Native patients. PNAS Nexus, Vol. 2, Issue. 8,

Betts, Juliana M. Weinman, Aaron L. Oliver, Jane Braddick, Maxwell Huang, Siyu Nguyen, Matthew Miller, Adrian Tong, Steven Y. C. Gibney, Katherine B. and Eslava-Schmalbach, Javier H. 2023. Influenza-associated hospitalisation and mortality rates among global Indigenous populations; a systematic review and meta-analysis. PLOS Global Public Health, Vol. 3, Issue. 4, p. e0001294.

Zeng, Zhang and Xiong, Huomei 2024. Evaluation and control strategy analysis of influenza cases in Jiujiang City, Jiangxi Province, China from 2018 to 2022. Geospatial Health, Vol. 19, Issue. 2,

Article contents

A case-control study of risk factors for death from 2009 pandemic influenza A(H1N1): is American Indian racial status an independent risk factor?

Summary

Keywords

INTRODUCTION

METHODS

Human participant protection and tribal review

RESULTS

DISCUSSION

APPENDIX. Investigative Team

ACKNOWLEDGEMENTS

DECLARATION OF INTEREST

References

REFERENCES

Save article to Kindle

Save article to Dropbox

Save article to Google Drive

Reply to: Submit a response

Your details

You have entered the maximum number of contributors

Conflicting interests