Vitamin D deficiency (VDD) is common among young women and causes various health problems, including those that occur during pregnancy and childbirth. Thus, we investigated the risk factors for VDD in young Japanese women and developed a simple risk scoring system called Vitamin D Deficiency Predicting Scoring (ViDDPreS).

A cross-sectional study, using the following factors for multivariate logistic regression analysis to create the ViDDPreS score: residential area, season, cumulative ambient ultraviolet-B irradiation, BMI, vitamin D supplement use, sun exposure habits, frequency of habitual food intake and eating habits. The subjects were randomly divided into development and test sets for analysis. Serum 25-hydroxivitamin D concentration of less than 20 ng/ml was defined as VDD.

Four regions (Hokkaido/Tohoku, Kanto, Chubu/Kinki/Shikoku and Kyushu/Okinawa) in Japan.

Five hundred and eighty-three healthy women aged 18–40 years.

In the development set, the VDD group (68·4 %) had higher proportions of the following variables than the non-VDD group: residential area outside the Kanto region; blood samples obtained in winter; low BMI (<18·5 kg/m2); vitamin D supplement non-users; short time regularly spent outside on weekdays; intake of fish, vitamin D-abundant fish, dried fish and redfish less than once a week. VDD risk was classified as low, medium or high according to the ViDDPreS scores including these contributing factors, with a test set C-index of 0·671.

We identified the risk factors for VDD in young Japanese women and developed a simple risk scoring system that enables us to assess VDD risk and aid in the development of appropriate prevention and treatment strategies for this population.

To evaluate prevalence of vitamin D deficiency and its associated factors in southern Iranian children.

Cross-sectional study. Anthropometric and pubertal characteristics were assessed by a trained physician. Physical activity and sun exposure were evaluated using standard questionnaires. Body composition measurements were performed using dual-energy X-ray absorptiometry. Serum Ca, P alkaline phosphatase and 25-hydroxyvitamin D (25(OH)D) were assessed in all children. Statistical analysis was done using the statistical software package IBM SPSS Statistics 18·0.

Iranian children (n 477) aged 9–18 years.

Fars Province, Iran, 2011.

Of the children, 81·3 % were 25(OH)D deficient. There was no significant difference in 25(OH)D concentration between boys and girls (P=0·3). 25(OH)D concentration was associated with BMI (r=−0·1, P=0·02), pubertal status (r=−0·08, P=0·04) and sun exposure (r=0·10, P=0·04). Fat mass index was associated with 25(OH)D concentration (r=−0·13, P=0·03), but not lean mass index (P=0·86). In multiple regression analysis with adjustment for confounding factors, age and puberty were found to be independently associated with 25(OH)D concentration (P=0·008 and P=0·006); there was a significant correlation between exercise and 25(OH)D concentration after adjustment for either BMI (P=0·01) or fat mass index (P=0·02).

25(OH)D deficiency is highly prevalent among children in the south of Iran. It is related to insufficient sun exposure, low physical activity, advancing age and pubertal stage. Measures should be taken to improve the health of southern Iranian children in this critical age group by preventing 25(OH)D deficiency.

To investigate university students’ knowledge, attitudes and practice (KAP) regarding vitamin D.

The students were requested to answer a questionnaire related to vitamin D and sun exposure. The consumption frequency of foods rich in vitamin D was assessed. Additionally, the intake of vitamin D-containing supplements was recorded.

A medical university in Nanjing, China.

Five hundred and fifteen medical students were included.

The highest rate of correct responses for the quiz was 68·0 %, while the lowest was 9·6 %. Most students lacked sun exposure because they did not want to get tanned; 82·7 % of students used some sun protection and sunscreen use was more popular in the female group. The consumption frequency of foods rich in vitamin D was low and 5·6 % of the students used vitamin D supplements. The students’ knowledge on vitamin D was derived mainly from the media and health professionals. Most of the students were interested to know more about vitamin D.

The present study suggested that medical students had little knowledge and unfavourable behaviours. They should get more health education through the media and health professionals. It is advisable to increase their consumption of foods rich in vitamin D.

To determine the vitamin D status of women of South Asian origin living in Auckland, New Zealand, and to investigate their attitudes and behaviours with regard to sun exposure.

Cross-sectional study.

Auckland, New Zealand.

Women of South Asian origin (n 235) aged 20 years and older were tested for serum 25(OH)D, and 228 were included in these analyses. Of these, 140 completed a questionnaire about attitudes and behaviours to sun exposure, and health motivation. Exclusion criteria included high dose (>1000 IU/d) supplementation with 25(OH)D3, or any supplementation with 1,25(OH)2D3.

As serum vitamin D concentrations were not normally distributed, data are reported as median (25th, 75th percentile). Median serum 25(OH)D3 was 27·5 (18·0, 41·0) nmol/l. Adequate concentrations (>50 nmol/l) were observed in only 16 % of the subjects. Concern about skin cancer and the strength of the New Zealand sun were the most prevalent reasons given for sun avoidance, with 65 % saying they did avoid the sun. However, a seasonal variation was observed, with concentrations reducing significantly (P < 0·001) from summer through to early spring by 19·5 nmol/l.

The results of the present study suggest that South Asian women are at high risk of hypovitaminosis D, due, in part, to deliberate sun avoidance and an indoor lifestyle, and that they are especially vulnerable in winter and spring.