To explore the extent to which micronutrient deficiencies (MND) affect children’s health-related quality of life (HRQoL), using vitamin D deficiency (VDD) as a case study.

Proxy valuation study to estimate the impact of VDD on the HRQoL of younger (0–4 years) and older (>4 years) children. We used the Child Health Utility 9 Dimension (CHU9D) questionnaire to estimate HRQoL for children within six VDD-related health states: ‘hypocalcaemic cardiomyopathy’, ‘hypocalcaemic seizures’, ‘active rickets’, ‘bone deformities’, ‘pain and muscle weakness’ and ‘subclinical VDD’.

Sampling was not restricted to any particular setting and worldwide experts were recruited.

Respondents were paediatric bone experts recruited through network sampling.

Thirty-eight experts completed the survey. The health state with the largest detrimental impact (mean score (se)) on children’s HRQoL was hypocalcaemic cardiomyopathy (0·47 (0·02)), followed by hypocalcaemic seizures (0·50 (0·02)) and active rickets (0·62 (0·02) in young children; 0·57 (0·02) in older children). Asymptomatic VDD had a modest but noticeable negative impact on HRQoL, attributed mostly to tiredness in both age groups and pain in the older paediatric population.

Elicitation of HRQoL from clinical experts suggests a negative impact of VDD on HRQoL, even if there is no recognizable clinical manifestation. HRQoL data from populations of patients with MND will inform public health policy decisions. In some settings, routine collection of HRQoL data alongside national nutrition surveys may help capture the full burden of MND and prioritize resources towards effective prevention.

Postpartum depression affects up to 20 % of new mothers within the first 12 months of parturition. 25-Hydroxyvitamin D (25(OH)D) has known importance in bone health, but it may also play an important role in other functions, including reproduction and fertility, immune function and mental health. This clinical commentary reviews literature evaluating 25(OH)D deficiency during pregnancy and the incidence of postpartum depressive symptomatology.

Narrative review, summary and recommendations.

A literature search revealed five relevant studies of antepartum women, three based in the USA, one in Turkey and one in Iran.

Three of the five studies measured serum 25(OH)D concentrations during the first or second trimester and discovered an association with 25(OH)D deficiency and depressive symptoms postpartum. One study determined an almost significant (P=0·058) inverse relationship with first-trimester 25(OH)D concentration and depressive symptoms postpartum, and the last study, which was a secondary analysis, did not find an association.

The Endocrine Society recommends routine vitamin D supplementation during pregnancy and lactation due to increased metabolic demand in the mother, but a recent Cochrane review recommended against screening. Vitamin D should be the target of more studies during pregnancy and the postpartum period since it appears to have an important role for both medical and mental health. Vitamin D supplementation is a relatively safe and cost-effective intervention during pregnancy, and it may prove to be important in the prevention of postpartum depression.

To study plasma 25-hydroxyvitamin D (25(OH)D) status of children in Kerala, southern India, and its relationship with sociodemographic variables.

Cross-sectional observational study.

Tertiary government hospital.

Children (n 296) with trivial acute illness were enrolled. Sun exposure and Ca and vitamin D intakes (7 d dietary recall) were documented. Serum Ca, P, alkaline phosphatase, plasma 25(OH)D and parathyroid hormone (PTH) were measured.

Prevalence of vitamin D deficiency (plasma 25(OH)D <30 nmol/l) was 11·1% (median, interquartile range (IQR): 52·6, 38·4–65·6 nmol/l). Children who ate fish daily had significantly higher plasma 25(OH)D than those who did not (median, IQR: 52·5, 40·8–68·9 v. 49·1, 36·2–60·7 nmol/l; P = 0·02). Those investigated in the months of March–May showed highest 25(OH)D v. those enrolled during other times (median, IQR: 58·7, 45·6–81·4 v. 45·5, 35·6–57·4 nmol/l; P <0·001). Plasma 25(OH)D correlated positively with serum P (r = 0·24, P <0·001) and Ca intake (r = 0·16, P 0·03), negatively with age (r = −0·13, P 0·03) and PTH (r = −0·22, P <0·001.). On linear regression, summer season (March–May), lower age, daily fish intake and higher Ca intake were independently associated with plasma 25(OH)D.

Prevalence of vitamin D deficiency is low in Kerala. The natural fish diet of coastal Kerala and the latitude may be protective. Public health policy in India should take account of this geographical diversity.

To investigate serum 25-hydroxyvitamin D (S-25(OH)D) concentration in a multi-ethnic population of northern Norway and determine predictors of S-25(OH)D, including Sami ethnicity.

Cross-sectional data from the second survey of the Population-based Study on Health and Living Conditions in Regions with Sami and Norwegian Populations (the SAMINOR 2 Clinical Survey, 2012–2014). S-25(OH)D was measured by the IDS-iSYS 25-Hydroxy Vitamin Dˢ assay. Daily dietary intake was assessed using an FFQ. BMI was calculated using weight and height measurements.

Ten municipalities of northern Norway (latitude 68°–70°N).

Males (n 2041) and females (n 2424) aged 40–69 years.

Mean S-25(OH)D in the study sample was 64·0 nmol/l and median vitamin D intake was 10·3 µg/d. The prevalence of S-25(OH)D<30 nmol/l was 1·9 % and <50 nmol/l was 24·7 %. In sex-specific multivariable linear regression models, older age, blood sample collection in September–October, solarium use, sunbathing holiday, higher alcohol intake (in females), use of cod-liver oil/fish oil supplements, use of vitamin/mineral supplements and higher intakes of vitamin D were significantly associated with higher S-25(OH)D, whereas being a current smoker and obesity were associated with lower S-25(OH)D. These factors explained 21–23 % of the variation in S-25(OH)D.

There were many modifiable risk factors related to S-25(OH)D, however no clear ethnic differences were found. Even in winter, the low prevalence of vitamin D deficiency found among participants with non-Sami, multi-ethnic Sami and Sami self-perceived ethnicity was likely due to adequate vitamin D intake.

To investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) and risk of incident diabetes in Hong Kong Chinese, after accounting for the effect of multiple bone- and mineral-related markers.

We conducted a retrospective study on the Hong Kong Osteoporosis Study cohort. Incident diabetes was ascertained using electronic medical records. Serum 25(OH)D was measured at baseline and its association with incident diabetes was evaluated using multivariable Cox proportional-hazard regression.

Individuals (n 4342) aged 20 years or above (1395 men, 2947 women; mean age 54·3 (sd 16·5) years) from the Hong Kong Osteoporosis Study, who were free of diabetes at baseline, were included.

During 40 124·7 person-years of follow-up (a median of 9·2 years), 443 participants developed diabetes. Mean 25(OH)D was 63·34 (sd 13·07) nmol/l. Age-, sex- and BMI-adjusted Cox proportional-hazard regression showed no significant difference in the risk of incident diabetes between the lowest and the highest quintiles of 25(OH)D. In the analysis of the interaction effect between 25(OH)D and serum Ca, the interaction term did not affect the risk of incident diabetes significantly (P = 0·694). Similarly, there was no significant interaction of different subgroups (age, sex, BMI, femoral-neck T-score, serum Ca levels) with serum 25(OH)D.

The present study finds that serum vitamin D level is not associated with the risk of incident diabetes in Hong Kong Chinese and this relationship is not modified by serum Ca level.

Both vitamin D and Fe micronutrient deficiencies are common in Saudi Arabia but the association between them is unclear. The present study aimed to determine whether Fe indices are associated with vitamin D status and other metabolic markers in Arab adolescents.

Single-centre, cross-sectional study gathering anthropometrics, glucose and lipid profile. Serum 25-hydroxyvitamin D (25(OH)D), Fe, total iron-binding capacity (TIBC), transferrin saturation (%) and other parameters were measured.

Vitamin D School Project Database, King Saud University (2014–2016).

Arab adolescents aged 10–17 years randomly selected from the Vitamin D School Project Database (170 Saudi students; 100 girls, seventy boys).

Among Fe indices, only TIBC was found to be significantly and inversely associated with 25(OH)D (r = −0·20; P < 0·01) and only in girls (r = −0·20; P < 0·05). Among cardiometabolic parameters, serum Fe was associated with TAG in boys (r = 0·36; P < 0·01) and inversely associated with HDL-cholesterol in girls (r = −0·29; P < 0·05). Age was the most significant predictor of serum Fe for all participants, accounting for 5 % (R2 = 0·05; P = 0·004) of variance perceived. Serum 25(OH)D and age, on the other hand, were the most significant predictors for TIBC, accounting for 10·1 % (R2 = 0·10; P < 0·001) of variance perceived.

Among healthy Arab adolescents, the association between vitamin D and Fe indices, particularly TIBC, is modest, inverse and sex-dependent. Larger studies with inclusion of markers such as hepcidin and ferritin, vitamin D metabolites and endogenous sex hormones may provide a clearer view of this complex association.

To explore the relationships of serum 25-hydroxyvitamin D (25(OH)D) with obesity and metabolic parameters in US children.

Cross-sectional analysis. We evaluated the associations between serum 25(OH)D and multiple measurements of adiposity, serum lipid concentrations, fasting glucose and insulin resistance in children aged 6–18 years with adjustments for multiple covariates.

The National Health and Nutrition Examination Survey, 2001–2006.

A nationally representative sample of 6311 children and adolescents aged 6–18 years.

Among US children and adolescents, the prevalence of vitamin D deficiency has been especially high in older children, girls and the non-Hispanic Black population. Higher odds of obesity were found at a 25(OH)D concentration of <30 nmol/l (deficiency) than at >50 nmol/l under both criteria for obesity in children (OR = 3·27, Ptrend ≤ 0.001). Moreover, increased odds of having abnormal HDL-cholesterol (OR = 1·71, Ptrend ≤ 0.001) and impaired insulin resistance (OR = 4·15, Ptrend ≤ 0·001) were found for children deficient in 25(OH)D compared with those with normal 25(OH)D concentrations. When the children and adolescents were stratified by gender, we found stronger associations between serum 25(OH)D concentration and both HDL-cholesterol and insulin resistance in girls. No association of 25(OH)D with any other metabolic parameter was found.

Our results suggest a potential harmful association between low serum 25(OH)D concentration and the risk of obesity among children. However, the underlying mechanisms require further investigation.

To assess sociodemographic, nutritional and health conditions associated with vitamin D sufficiency among young Brazilian children living at different latitudes.

Cross-sectional analysis with a four-level model of inflammation to correct micronutrient concentrations. Prevalence ratios (PR; 95 % CI) were estimated for factors associated with vitamin D sufficiency (≥50 nmol/l), adjusting for child’s sex, age, skin colour, stunting and vitamin A+D supplementation.

Primary health-care units in four Brazilian cities located at lower (7°59′26·9016″S and 9°58′31·3864″S) and higher latitudes (16°41′12·7752″S and 30°2′4·7292″S).

In total 468 children aged 11–15 months were included in the analysis.

Only 31·8 % of children were vitamin D sufficient (concentration <30 nmol/l and <50 nmol/l among 32·9 and 68·2 %, respectively). Living at higher latitudes was associated with reduced prevalence of vitamin D sufficiency compared with lower latitudes (PR = 0·65; 95 % CI 0·49, 0·85). Maternal education ≥9 years positively influenced a sufficient vitamin D status in children. After correction for inflammatory status, each increase of 1 µmol/l in vitamin A concentration was associated with a 1·38-fold higher prevalence of vitamin D sufficiency (95 % CI 1·18, 1·61). Progressive decline in the prevalence of vitamin D sufficiency was associated with marginal and deficient status of vitamin A (Ptrend = 0·001).

Lower latitude, higher maternal education and vitamin A concentration were positively associated with vitamin D sufficiency in young Brazilian children. These findings are relevant for planning public health strategies for improving vitamin D status starting in early infancy.

A recent meta-analysis suggested that the association between vitamin D and risk of hypertension was markedly stronger in women aged <55 years in observational data, while the association became null in women aged ≥55 years. We therefore hypothesized that this difference in associations might potentially be caused by the change in oestrogen around menopause. Our objective was to investigate associations between vitamin D status and hypertension risk and to evaluate those associations as they may differ according to menopausal status.

A cross-sectional population survey conducted by the US Centers for Disease Control and Prevention, National Center for Health Statistics.

The National Health and Nutrition Examination Surveys (NHANES) 2007–2010 formed the setting for the present study.

We analysed data from 2098 premenopausal women and 2298 postmenopausal women.

After adjustment for sociodemographic, behavioural and dietary factors, higher concentrations both of serum total 25-hydroxyvitamin D (25(OH)D) and serum 25-hydroxycholecalciferol (25(OH)D3) revealed significant dose-dependent trends with lower risk of hypertension (Ptrend = 0·005 and 0·014, respectively) in premenopausal women. In those women, 25(OH)D ≥ 50 nmol/l (sufficient; in contrast to deficient, vitamin D < 30 nmol/l) appeared to have a protective effect against hypertension (OR = 0·64, 95 % CI 0·39, 1·02 for total 25(OH)D and OR = 0·60, 95 % CI 0·36, 1·00 for 25(OH)D3). Neither association with hypertension was observed in postmenopausal women.

Serum 25(OH)D concentrations were associated with lower risk of hypertension in premenopausal women, but not in postmenopausal women.

This study aimed to analyse the relationship between vitamin D deficiency and the season when the blood sample was obtained from subjects with chronic hepatitis C (CHC) infection.

A cross-sectional study was conducted on a representative sample. Vitamin D deficiency was defined as a serum 25-hydroxyvitamin D [25(OH)D] concentration <50 nmol/l, based on the values set forth by the Endocrine Society guideline for higher-risk populations. Seasonality was defined according to solstices and equinoxes. The association of seasonality and clinical/laboratory characteristics with vitamin D deficiency was assessed using a multivariate logistic regression analysis.

NUPAIG Viral Hepatitis Outpatient Clinic of the Universidade Federal de São Paulo – Brazil.

Adult subjects with CHC infection (n 306).

The prevalence of vitamin D deficiency was 16 %, whereas the median serum 25(OH)D concentration was 87 (interquartile range, 59; third quartile = 118) nmol/l. Serum concentration was consistently lower in samples collected in spring and winter than in other seasons. In multivariate analysis, vitamin D deficiency was found to be independently associated with male gender, serum albumin concentration and with samples drawn in winter and spring.

The findings show not only the relevance to consider season as a factor influencing 25(OH)D concentration but also the need to actively screen for hypovitaminosis D in all patients with CHC infection, especially in females and those with low albumin concentration.

We investigated the determinants of serum 25-hydroxyvitamin D [S-25(OH)D] and dietary vitamin D sources among three immigrant groups in Finland and compared their S-25(OH)D to the general Finnish population.

Cross-sectional population-based Migrant Health and Wellbeing Study and the nationally representative Finnish Health 2011 Survey. S-25(OH)D was standardised according to the Vitamin D Standardisation Program. Vitamin D sources were assessed by interview.

Six different municipalities in Finland (60°–63°N).

Immigrants aged 18–64 years (446 Russians, 346 Somalis, 500 Kurds), 798 Finns aged 30–64 years.

The mean of S-25(OH)D was 64 (95 % CI 62, 66), 44 (95 % CI 41, 46), 35 (95 % CI 34, 37) and 64 (95 % CI 62, 66) nmol/l for Russians, Somalis, Kurds and Finns, respectively. S-25(OH)D among Somalis and Kurds was lower compared with Finns (P < 0·001). The prevalence of vitamin D deficiency (S-25(OH)D <30 nmol/l) and insufficiency (S-25(OH)D <50 nmol/l) was higher among immigrants than Finns (P < 0·001). Vitamin D-rich foods differed between the groups; vitamin D-fortified fat spread consumption was higher among Somalis (91 %) than among Russians (73 %) and Kurds (60 %); fish was less consumed among Kurds (17 %) than among Russians (43 %) and Somalis (38 %); and 57 % Russians, 56 % Kurds and 36 % Somalis consumed vitamin D-fortified dairy daily (P < 0·001 for all). Daily smoking, alcohol consumption and winter blood sampling were determinants of vitamin D insufficiency (P ≤ 0·03). Older age, physical activity, fish and vitamin D-fortified dairy consumption were associated with lower odds of insufficiency (P ≤ 0·04).

Vitamin D status differed among immigrant groups and the determinants are, to some degree, associated with learned or existing cultural behaviours.

To investigate whether vitamin D status predicts weight gain or increase in waist circumference during the 11-year follow-up in general adult population.

A population-based longitudinal study.

The study was conducted using data from the nationally representative Health 2000/2011 Survey. The analyses were based on regression models adjusted for sociodemographic and lifestyle factors.

Weight, waist circumference and vitamin D status (serum 25-hydroxyvitamin D concentration analysed with radioimmunoassay) were measured from 2924 participants aged 30–64 years at baseline.

In men, low vitamin D status at baseline predicted ≥10 % increase in waist circumference during the follow-up when adjusted for age only (OR for sufficient v. deficient S-25(OH)D 0·41; 95 % CI 0·25, 0·67; P for trend <0·01), but the association with weight gain was only borderline significant. After adjustment for potential confounders, low vitamin D status remained a significant predictor of increase in waist circumference, but the association with weight gain was further attenuated. In women, vitamin D status at baseline did not predict weight gain or increase in waist circumference.

Our results suggest that vitamin D insufficiency may be a risk factor of abdominal obesity among men but not among women. In men, it may also increase the risk of weight gain. Further studies are required to confirm these findings and examine potential mechanisms behind them. There is also a possibility that vitamin D is a biomarker of healthy lifestyle rather than an independent risk factor for obesity.

Maternal vitamin D level in pregnancy may have implications for both the mother and fetus. Deficiency of vitamin D has been linked to several pregnancy complications and fetal skeletal health. Smoking has been associated with reduced serum level of the vitamin D metabolite, 25-hydroxyvitamin D (25(OH)D).

A nested case–control study within the Finnish Maternity Cohort, a population-based cohort which includes first-trimester sera from 98 % of pregnancies in Finland since 1987. The selection consisted of women with uncomplicated pregnancies. We studied serum concentration of 25(OH)D in 313 non-smoking and forty-six self-reported smoking pregnant women.

We hypothesize that pregnant smokers may have an increased risk of low 25(OH)D levels especially during winter months.

A control group from an unpublished pregnancy complication study consisting of 359 uncomplicated pregnancies. Individuals who reported that they do not smoke were considered ‘non-smokers’ (n 313) and those who reported continued smoking after the first trimester of pregnancy were considered ‘smokers’ (n 46).

Smokers had significantly lower levels of 25(OH)D irrespective of sampling time (P<0·0001). Furthermore, during the low sun-exposure season, only 14 % of smokers met the guideline level of 40 nmol/l for serum 25(OH)D in comparison with 31 % of non-smokers.

Expectant mothers who smoke have an increased risk of vitamin D deficiency during low sun-exposure months in northern regions. Further studies are needed to assess the associated risks for maternal and fetal health as well as possible long-term implications for the infant.