Potentially modifiable determinants of vitamin D status in an older population in the Netherlands: the Hoorn Study

BACKGROUND: Inadequate vitamin D status is common in many populations around the world. OBJECTIVE: The aim was to evaluate potentially modifiable determinants of vitamin D status in an older population. DESIGN: This was a cross-sectional study from a population-based cohort including 538 white Dutch men and women aged 60-87 y. Vitamin D status was assessed by plasma 25-hydroxyvitamin D [25(OH)D] concentrations. RESULTS: In the winter period, 51% of the subjects had 25(OH)D concentrations <50.0 nmol/L. Greater body fatness and less time spent on outdoor physical activity were associated with worse vitamin D status. Regular use of vitamin D-fortified margarine products [odds ratio (OR) in a comparison of intake of >or=20 g/d with none: 0.41; 95% CI: 0.20, 0.86; P for trend < 0.001], fatty fish (OR for servings of >or=2/mo versus none: 0.41; 95% CI: 0.16, 1.04; P for trend = 0.01), and vitamin D-containing supplements (OR for >or= 1/d versus none: 0.33; 95% CI: 0.17, 0.63; P for trend < 0.001) were inversely associated with vitamin D inadequacy [25(OH)D <50.0 nmol/L]. We estimated that combined use of margarine products (20 g/d), fatty fish (100 g/wk), and vitamin D supplements (>or=1/d) was associated with a 16.8 nmol/L higher 25(OH)D concentration than was the use of none of these. However, none of the participants reached these intakes for all 3 factors. CONCLUSION: Because few foods are vitamin D-fortified and the amounts of vitamin D in supplements are low, it is difficult to achieve adequate vitamin D status through increasing intakes in the Netherlands and in countries with similar policies.     

Are national vitamin D guidelines sufficient to maintain adequate blood levels in children?

BACKGROUND: Vitamin D insufficiency (defined as 25-hydroxyvitamin D [25(OH)D] concentrations <40 nmol/L) may be associated with subclinical adverse effects on bone mineralization. The current vitamin D status of children and adolescents in Canada has not been described. The purpose of this study was to describe the association between 25(OH)D serum concentration and dietary vitamin D intake, and other potential determinants of vitamin D status, among a sample of children and adolescents aged 2-16 years presenting to a pediatric emergency department in Edmonton, Alberta (latitude 52 degrees N) at the end of winter. METHODS: In early April 2003, 90 patients between the ages of 2 and 16 years who presented to the pediatric emergency department in Edmonton volunteered to participate. All participants and/or parents or guardians completed questionnaires regarding potential risk factors for vitamin D insufficiency, detailed dietary assessments, and anthropometric measurements. Serum 25(OH)D concentrations were measured in 68 of 90 participants. RESULTS: The mean serum 25(OH)D concentration was 47.2 nmol/L (95% CI 43.8-50.8 nmol/L). 34% of participants had vitamin D insufficiency (<40 nmol/L) and 6% were deficient (<25 nmol/L). Boys and girls aged 9-16 years had a prevalence of insufficiency of 69% and 35% respectively, while boys and girls 2-8 years old had a prevalence of insufficiency of 22% and 8% respectively. Dietary vitamin D intake per kilogram body weight was the most important independent determinant of 25(OH)D concentration (r = 0.446, p<0.001). Vitamin D intake, age and male sex best predicted insufficiency. No subject was insufficient if they had an intake >0.45 mcg/kg/day. INTERPRETATION: Vitamin D insufficiency may be common among children and adolescents at the beginning of spring. The risk may be highest among older children because vitamin D intake does not adequately rise in proportion with increases in body mass. Further studies are needed to assess whether Canadian dietary vitamin D recommendations should be changed.     

Vitamin D status was not associated with anxiety,depression, or health-related quality of life in Middle Eastern and African-born immigrants in Sweden

Active vitamin D is a neurosteroid that may modulate brain function. Associations between vitamin D deficiency and depression and anxiety have been demonstrated. We hypothesized that there was an association between anxiety, depression, and health-related quality of life (HRQOL) and vitamin D status. To test this hypothesis, we examined the association between anxiety, depression, and HRQOL and 25-hydroxyvitamin D (25[OH]D) concentrations in the Middle Eastern and African-born immigrant population. All immigrants aged 25-65 years, born in 9 African or Middle Eastern countries, and living in 3 districts in Umeå (n = 1306) were invited, with 195 English- or Swedish-speaking immigrants (104 men and 91 women) participated. Anxiety and depression were measured using the Hospital Anxiety and Depression scale. HRQOL was measured using EuroQoL-5 Dimension 3 Level Questionnaire and EuroQoL Visual Analogue Scale. Serum 25(OH)D was measured using liquid chromatography–tandem mass spectrometry. Associations were determined using logistic and linear regression. Analyses were adjusted for sex, age, origin, socioeconomic factors, lifestyle, chronic diseases, and obesity. In total, 71% had 25(OH)D less than 50 nmol/L and 11% had 25(OH)D less than 25 nmol/L. Anxiety, depression, and HRQOL were not associated with 25(OH)D in the immigrant population. Anxiety was common in female immigrants from the Middle East (32.7%); and after adjustment, lower 25(OH)D concentrations were associated with higher risk of anxiety (25[OH]D ≤ 49 nmol/L vs 25[OH]D ≥ 50 nmol/L: odds ratio 23.2 [95% confidence interval 1.97 - 271.9] P = .012) in this subgroup only; however, reverse causality could not be excluded. In conclusion, the study showed no association between depression, anxiety, or HRQOL and vitamin D status in the immigrant population.     

Subclinical vitamin D deficiency is increased in adolescent girls who wear concealing clothing

Vitamin D deficiency continues to be a worldwide problem, especially in developing countries. The aim of this study was to investigate potential risk factors for vitamin D deficiency. Girls (n = 89) aged 13 to 17 y were enrolled in the study. Study subjects were stratified into 3 groups: Group I included girls living in a suburban area; Group II girls lived in an urban area, and Group III girls lived in an urban area and wore concealing clothes for religious reasons. At the end of winter (in April) serum 25-hydroxyvitamin D [25(OH)D] levels were measured and dietary data were collected using questionnaires. Vitamin D deficiency was defined as a serum 25(OH)D concentration < 25 nmol/L, and insufficiency as a 25(OH)D concentration between 25 and 50 nmol/L. The lumbar and femur neck bone mineral densities (BMD) were measured using dual X-ray absorptiometry (DEXA). Overall, 39 girls (43.8%) had vitamin D insufficiency and 19 (21.3%) had vitamin D deficiency. In group III (wearing covered dress) the serum 25(OH)D concentrations (28.13 +/- 12.53 nmol/L) were significantly lower than in the other 2 groups, and within this group, 50% of girls were vitamin D deficient. The lumbar and femur neck BMD of girls with lower 25(OH)D levels did not differ from those with adequate vitamin D levels. We conclude that vitamin D deficiency is an important problem in Turkish adolescent girls, especially in those who follow a religious dress code; therefore, vitamin D supplementation appears to be necessary for adolescent girls.     

Serum 25-hydroxyvitamin D: distribution and determinants in the Swiss population.

The serum 25-hydroxyvitamin D [25(OH)D] concentration was measured in a representative sample of the general adult population in Switzerland (n = 3276). The median concentration was 46 nmol/L and no significant difference was found between men and women. Between the ages of 25 and 74 y, 25(OH)D was not significantly correlated with age (r2 = 0.01). Six percent of the population was vitamin D deficient [ie, 25(OH)D less than or equal to 20 nmol/L] and between 34% and 95% had a relatively low concentration of vitamin D (ie, less than 38 or less than 95 nmol/L, respectively). Among the determinants of low 25(OH)D were indicators of little sunshine exposure, such as the winter season [odds ratio (OR) 2.4, 1.5-3.7 (95% confidence interval)] and less than 30 min of time spent outdoors daily by individuals greater than 65 y of age (OR 5.6, 1.5-21.2), as well as indicators of low nutritional intake of vitamin D, such as the absence of regular intake of butter or margarine (OR 2.0, 1.3-3.1) and the consumption of few dairy products (OR 1.7, 1.2-2.4).     

Vitamin D Deficiency and Its Association with Iron Deficiency in African Children

Vitamin D regulates the master iron hormone hepcidin, and iron in turn alters vitamin D metabolism. Although vitamin D and iron deficiency are highly prevalent globally, little is known about their interactions in Africa. To evaluate associations between vitamin D and iron status we measured markers of iron status, inflammation, malaria parasitemia, and 25-hydroxyvitamin D (25(OH)D) concentrations in 4509 children aged 0.3 months to 8 years living in Kenya, Uganda, Burkina Faso, The Gambia, and South Africa. Prevalence of iron deficiency was 35.1%, and prevalence of vitamin D deficiency was 0.6% and 7.8% as defined by 25(OH)D concentrations of <30 nmol/L and <50 nmol/L, respectively. Children with 25(OH)D concentrations of <50 nmol/L had a 98% increased risk of iron deficiency (OR 1.98 [95% CI 1.52, 2.58]) compared to those with 25(OH)D concentrations >75 nmol/L. 25(OH)D concentrations variably influenced individual markers of iron status. Inflammation interacted with 25(OH)D concentrations to predict ferritin levels. The link between vitamin D and iron status should be considered in strategies to manage these nutrient deficiencies in African children.     

High prevalence of vitamin D deficiency in pregnant non-Western women in The Hague, Netherlands

BACKGROUND: Vitamin D deficiency is common in dark-skinned persons living in northern countries. Vitamin D deficiency during pregnancy may have serious consequences for both mother and child. OBJECTIVE: The objective was to ascertain the prevalence of vitamin D deficiency in pregnant women of several ethnic backgrounds who were living in The Hague, a large city in the Netherlands. DESIGN: Midwives whose practice was visited by a large number of non-Western immigrants added the assessment of serum 25-hydroxyvitamin D [25(OH)D] to the standard blood test given to women who visited the practice during week 12 of pregnancy. Subsequently, the Municipal Health Service collected additional data from the midwives' files (June 2002 through March 2004): background variables, use of tobacco or alcohol or drugs, and infectious diseases. The women were grouped ethnically as Western, Turkish, Moroccan, and other non-Western. RESULTS: The vitamin D concentrations of 358 women were found in the midwives' files. Of these women, 29% were Western, 22% were Turkish, and 19% were Moroccan. Mean serum 25(OH)D concentrations in Turkish (15.2 +/- 12.1 nmol/L), Moroccan (20.1 +/- 13.5 nmol/L), and other non-Western women (26.3 +/- 25.9 nmol/L) were significantly (P 相似文献   

Residential Greenness Alters Serum 25(OH)D Concentrations: A Longitudinal Cohort of Chinese Older Adults

ObjectivesVitamin D deficiency is prevalent among older adults. We aimed to study whether residential greenness could alter serum 25(OH)D concentrations as a possible mechanism of residential greenness's positive health effects.DesignA longitudinal cohort study.Setting and ParticipantsWe included older adults aged ≥65 years from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) with follow-up between 2012 and 2014.MethodsWe measured residential greenness by calculating annual average Normalized Difference Vegetation Index (NDVI) in a 500 m radius by using satellite images around each participant's residential address. Serum 25-hydroxyvitamin D (25(OH)D) concentration was dichotomized into 2 categories: nondeficiency (≥50 nmol/L) and deficiency (<50 nmol/L). We used the generalized estimating equation to examine the relationship between annual average NDVI and serum 25(OH)D.ResultsWe included 1336 participants in our analysis. The annual average NDVI was 0.49, and mean serum 25(OH)D was 43 nmol/L at baseline. Each 0.1-unit increase in annual average NDVI was associated with a 13% higher odds of vitamin D nondeficiency [95% confidence interval (CI): 1.01, 1.26]. The association was stronger among men [odds ratio (OR): 1.17, 95% CI: 1.02, 1.35] than women (OR: 1.08, 95% CI: 0.91, 1.29) and also stronger among those who were free of activities of daily living (ADL) disability at baseline (OR: 1.12, 95% CI: 1.00, 1.25). During the follow-up period, the participants who lived in greener areas were more likely to have an improved, rather than stable or deteriorated, vitamin D status (OR: 1.94, 95% CI: 1.51, 2.51).Conclusions and ImplicationsOur study suggests that higher levels of residential greenness are associated with higher serum 25(OH)D concentrations, which has implications for prevention of vitamin D deficiency among older adults.     

Vitamin D status of infants in northeastern rural Bangladesh: preliminary observations and a review of potential determinants

Vitamin D deficiency is a global public-health concern, even in tropical regions where the risk of deficiency was previously assumed to be low due to cutaneous vitamin D synthesis stimulated by exposure to sun. Poor vitamin D status, indicated by low serum concentrations of 25-hydroxyvitamin D [25(OH)D], has been observed in South Asian populations. However, limited information is available on the vitamin D status of young infants in this region. Therefore, to gain preliminary insights into the vitamin D status of infants in rural Bangladesh, 25(OH)D was assessed in a group of community-sampled control participants in a pneumonia case-control study in rural Sylhet, Bangladesh (25 degrees N) during the winter dry season (January-February). Among 29 infants aged 1-6 months, the mean 25(OH)D was 36.7 nmol/L [95% confidence interval (CI) 30.2-43.2]. The proportion of infants with vitamin D deficiency defined by 25(OH)D < 25 nmol/L was 28% (95% CI 10-45), 59% (95% CI 40-78) had 25(OH)D < 40 nmol/L, and all were below 80 nmol/L. From one to six months, there was a positive correlation between age and 25(OH)D (Spearman = 0.65; p = 0.0001). Within a larger group of 74 infants and toddlers aged 1-17 months (cases and controls recruited for the pneumonia study), young age was the only significant risk factor for vitamin D deficiency [25(OH)D < 25 nmol/L]. Since conservative maternal clothing practices (i.e. veiling) and low frequency of intake of foods from animal source (other than fish) were common among the mothers of the participants, determinants of low maternal-infant 25(OH)D in Bangladesh deserve more detailed consideration in future studies. In conclusion, the vitamin D status in young infants in rural Sylhet, Bangladesh, was poorer than might be expected based on geographic considerations. The causes and consequences of low 25(OH)D in infancy and early childhood in this setting remain to be established.     

Pharmacokinetics of High-Dose Weekly Oral Vitamin D3 Supplementation during the Third Trimester of Pregnancy in Dhaka,Bangladesh

A pharmacokinetic study was conducted to assess the biochemical dose-response and tolerability of high-dose prenatal vitamin D3 supplementation in Dhaka, Bangladesh (23°N). Pregnant women at 27–30 weeks gestation (n = 28) were randomized to 70,000 IU once + 35,000 IU/week vitamin D3 (group PH: pregnant, higher dose) or 14,000 IU/week vitamin D3 (PL: pregnant, lower dose) until delivery. A group of non-pregnant women (n = 16) was similarly administered 70,000 IU once + 35,000 IU/week for 10 weeks (NH: non-pregnant, higher-dose). Rise (∆) in serum 25-hydroxyvitamin D concentration ([25(OH)D]) above baseline was the primary pharmacokinetic outcome. Baseline mean [25(OH)D] were similar in PH and PL (35 nmol/L vs. 31 nmol/L, p = 0.34). A dose-response effect was observed: ∆[25(OH)D] at modeled steady-state was 19 nmol/L (95% CI, 1 to 37) higher in PH vs. PL (p = 0.044). ∆[25(OH)D] at modeled steady-state was lower in PH versus NH but the difference was not significant (−15 nmol/L, 95% CI −34 to 5; p = 0.13). In PH, 100% attained [25(OH)D] ≥ 50 nmol/L and 90% attained [25(OH)D] ≥ 80 nmol/L; in PL, 89% attained [25(OH)D] ≥ 50 nmol/L but 56% attained [25(OH)D] ≥ 80 nmol/L. Cord [25(OH)D] (n = 23) was slightly higher in PH versus PL (117 nmol/L vs. 98 nmol/L; p = 0.07). Vitamin D3 was well tolerated; there were no supplement-related serious adverse clinical events or hypercalcemia. In summary, a regimen of an initial dose of 70,000 IU and 35,000 IU/week vitamin D3 in the third trimester of pregnancy was non-hypercalcemic and attained [25(OH)D] ≥ 80 nmol/L in virtually all mothers and newborns. Further research is required to establish the safety of high-dose vitamin D3 in pregnancy and to determine if supplement-induced [25(OH)D] elevations lead to maternal-infant health benefits.     

Risk factors for low serum 25-hydroxyvitamin D concentrations in otherwise healthy children and adolescents

BACKGROUND: Serum 25-hydroxyvitamin D [25(OH)D] concentrations serve as a biomarker for vitamin D stores. Prior studies have not examined the risk factors for low vitamin D concentrations in a multiethnic sample of US youth across a broad age range. OBJECTIVE: The objective was to determine the prevalence of and factors associated with low concentrations of 25(OH)D in children and adolescents. DESIGN: Serum 25(OH)D concentrations were measured in 382 healthy children aged 6-21 y living in the northeastern United States. Dietary and supplemental vitamin D intake was assessed by interview. Fat and lean mass were assessed by dual-energy X-ray absorptiometry. Multivariable ordinal logistic regression was used to determine factors associated with decreased concentrations of 25(OH)D. RESULTS: The median concentration of 25(OH)D was 28 ng/mL (interquartile range: 19-35 ng/mL), and 55% of subjects had 25(OH)D concentrations <30 ng/mL. 25(OH)D concentrations were inversely correlated with parathyroid hormone concentrations (Spearman's r=-0.31, P<0.001) but were not significantly correlated with 1,25-dihydroxyvitamin D concentrations. In the multivariable model, older age (P<0.001), black race [odds ratio (OR): 14.2; 95% CI: 8.53, 23.5], wintertime study visit (OR: 3.55; 95% CI: 2.29, 5.50), and total daily vitamin D intake <200 IU (OR: 1.58; 95% CI: 1.02, 2.46) were associated with low vitamin D concentrations. Fat and lean mass were not independently associated with vitamin D status in this healthy-weight sample. CONCLUSION: Low serum 25(OH)D concentrations are prevalent in otherwise healthy children and adolescents in the northeastern United States and are related to low vitamin D intake, race, and season.     

Low serum concentrations of 25-hydroxyvitamin D in older persons and the risk of nursing home admission

BACKGROUND: The prevalence of vitamin D deficiency in nursing home patients is high. OBJECTIVE: We aimed to ascertain whether lower serum 25-hydroxyvitamin D [25(OH)D] concentrations increase the risk of future nursing home admission and early death. DESIGN: We included 1260 independent, community-dwelling persons aged > or =65 y who were participating in the Longitudinal Aging Study Amsterdam (1995-1996). Study outcomes were time to nursing home admission during 6 y of follow-up and time to death until 1 April 2003. RESULTS: Vitamin D deficiency [25(OH)D < 25 nmol/L] and insufficiency [25(OH)D = 25-49.9 nmol/L] were present in 127 (10.1%) and 462 (36.7%) subjects, respectively. During follow-up, 138 subjects (11.0%) were admitted to nursing homes, and 380 subjects (30.2%) died. The risk of nursing home admission for participants with 25(OH)D deficiency was 53 cases per 1000 person-years higher than that for those with high 25(OH)D (> or =75 nmol/L) concentrations (58 compared with 5 cases). After adjustment for potential confounders, the hazard ratio (95% CI) of nursing home admission was 3.48 (1.39, 8.75) for vitamin D-deficient, 2.77 (1.17, 6.55) for vitamin D-insufficient, and 1.92 (0.79, 4.66) for vitamin D-borderline persons as compared with persons with high 25(OH)D (P for trend = 0.002). The results remained after additional adjustment for frailty indicators. Lower 25(OH)D was associated with higher mortality risk, but this association was not significant after adjustment for frailty indicators. CONCLUSION: Lower serum 25(OH)D concentrations in older persons are associated with a greater risk of future nursing home admission and may be associated with mortality.     

An updated systematic review and meta-analysis of the efficacy of vitamin D food fortification

Food fortification is a potentially effective public health strategy to increase vitamin D intakes and circulating 25-hydroxyvitamin D [25(OH)D] concentrations. We updated a previous systematic review to evaluate current evidence from randomized controlled intervention studies in community-dwelling adults of the effect of fortified foods on 25(OH)D concentrations. Ovid MEDLINE, PubMed, CINAHL, Embase, and Cochrane Central Register of Controlled Trials were searched for randomized controlled intervention studies with vitamin D-fortified foods in free-living adults and data on circulating 25(OH)D. Two reviewers independently screened 441 papers for eligibility and extracted the relevant data. A meta-analysis of the absolute mean change in circulating 25(OH)D concentrations was conducted using a random effects model. Sixteen studies from 15 publications were included, of which 14 showed a significant effect of fortified foods on 25(OH)D concentrations. Heterogeneity was high (P = <0.0001, I(2) = 89%) and was partly explained by dose, latitude (range, 3-60°), and baseline 25(OH)D (range, 24.0-83.6 nmol/L). When combined in a random effects analysis (n = 1513; 767 treated, 746 controls), a mean individual intake of ~11 μg/d (440 IU/d) from fortified foods (range, 3-25 μg/d) increased 25(OH)D by 19.4 nmol/L (95% CI: 13.9, 24.9), corresponding to a 1.2 nmol/L (95% CI: 0.72, 1.68) increase in 25(OH)D for each 1 μg ingested. Vitamin D food fortification increases circulating 25(OH)D concentrations in community-dwelling adults. Safe and effective food-based strategies could increase 25(OH)D across the population distribution and prevent vitamin D deficiency with potential benefit for public health.     

Vitamin D status among immigrant mothers from Pakistan, Turkey and Somalia and their infants attending child health clinics in Norway

High prevalences of vitamin D deficiency have been reported in non-Western immigrants moving to Western countries, including Norway, but there is limited information on vitamin D status in infants born to immigrant mothers. We aimed to describe the vitamin D status and potentially correlated factors among infants aged 6 weeks and their mothers with Pakistani, Turkish or Somali background attending child health clinics in Norway. Eighty-six healthy infants and their mothers with immigrant background were recruited at the routine 6-week check-up at nine centres between 2004 and 2006. Venous or capillary blood was collected at the clinics from the mother and infant, and serum separated for analysis of 25-hydroxyvitamin D (s-25(OH)D) and intact parathyroid hormone (s-iPTH). The mean maternal s-25(OH)D was 25.8 nmol/l, with 57 % below 25 nmol/l and 15 % below 12.5 nmol/l. Of the mothers, 26 % had s-iPTH>5.7 pmol/l. For infants, mean s-25(OH)D was 41.7 nmol/l, with 47 % below 25 nmol/l and 34 % below 12.5 nmol/l. s-25(OH)D was considerably lower in the thirty-one exclusively breast-fed infants (mean 11.1 nmol/l; P < 0.0001). Use of vitamin D supplements and education showed a positive association with maternal s-25(OH)D. There was no significant association between mother's and child's s-25(OH)D, and no significant ethnic or seasonal variation in s-25(OH)D for mothers or infants. In conclusion, there is widespread vitamin D deficiency in immigrant mothers and their infants living in Norway. Exclusively breast-fed infants who did not receive vitamin D supplements had particularly severe vitamin D deficiency.     

Serum 25-hydroxyvitamin D in a West African population of tuberculosis patients and unmatched healthy controls

BACKGROUND: Little is known regarding vitamin D deficiency (VDD) in African populations and in tuberculosis (TB) patients. VDD has been shown to be associated with TB. OBJECTIVE: We aimed to compare the degree of vitamin D insufficiency (VDI) and VDD in TB patients and healthy adult controls in a West African population. DESIGN: An unmatched case-control study was performed at a Demographic Surveillance Site in Guinea-Bissau. Serum 25-hydroxyvitamin D(3) [25(OH)D(3)] concentrations were measured in 362 TB patients and in 494 controls. RESULTS: Hypovitaminosis D [25(OH)D(3) 相似文献   

Prevalence and Predictors of Vitamin D Deficiency and Insufficiency among Pregnant Rural Women in Bangladesh

Although adequate vitamin D status during pregnancy is essential for maternal health and to prevent adverse pregnancy outcomes, limited data exist on vitamin D status and associated risk factors in pregnant rural Bangladeshi women. This study determined the prevalence of vitamin D deficiency and insufficiency, and identified associated risk factors, among these women. A total of 515 pregnant women from rural Bangladesh, gestational age ≤ 20 weeks, participated in this cross-sectional study. A separate logistic regression analysis was applied to determine the risk factors of vitamin D deficiency and insufficiency. Overall, 17.3% of the pregnant women had vitamin D deficiency [serum 25(OH)D concentration <30.0 nmol/L], and 47.2% had vitamin D insufficiency [serum 25(OH)D concentration between 30–<50 nmol/L]. The risk of vitamin D insufficiency was significantly higher among nulliparous pregnant women (OR: 2.72; 95% CI: 1.75–4.23), those in their first trimester (OR: 2.68; 95% CI: 1.39–5.19), anaemic women (OR: 1.53; 95% CI: 0.99–2.35; p = 0.056) and women whose husbands are farmers (OR: 2.06; 95% CI: 1.22–3.50). The risk of vitamin deficiency was significantly higher among younger pregnant women (<25 years; OR: 2.12; 95% CI: 1.06–4.21), nulliparous women (OR: 2.65; 95% CI: 1.34–5.25), women in their first trimester (OR: 2.55; 95% CI: 1.12–5.79) and those with sub-optimal vitamin A status (OR: 2.30; 95% CI: 1.28–4.11). In conclusion, hypovitaminosis D is highly prevalent among pregnant rural Bangladeshi women. Parity and gestational age are the common risk factors of vitamin D deficiency and insufficiency. A husband’s occupation and anaemia status might be important predictors of vitamin D insufficiency, while younger age and sub-optimal vitamin A status are risk factors for vitamin D deficiency in this population.     

Vitamin D Intake and Status in 6-Year-Old Icelandic Children Followed up from Infancy

High serum 25-hydroxyvitamin D (25(OH)D) levels have been observed in infants in Nordic countries, likely due to vitamin D supplement use. Internationally, little is known about tracking vitamin D status from infancy to childhood. Following up 1-year-old infants in our national longitudinal cohort, our aims were to study vitamin D intake and status in healthy 6-year-old Icelandic children (n = 139) and to track vitamin D status from one year of age. At six years, the mean 25(OH)D level was 56.5 nmol/L (SD 17.9) and 64% of children were vitamin D sufficient (25(OH)D ≥ 50 nmol/L). A logistic regression model adjusted for gender and breastfeeding showed that higher total vitamin D intake (Odds ratio (OR) = 1.27, 95% confidence interval (CI) = 1.08–1.49), blood samples collected in summer (OR = 8.88, 95% CI = 1.83–43.23) or autumn (OR = 5.64, 95% CI = 1.16–27.32) compared to winter/spring, and 25(OH)D at age one (OR = 1.02, 95% CI = 1.002–1.04) were independently associated with vitamin D sufficiency at age six. The correlation between 25(OH)D at age one and six was 0.34 (p = 0.003). Our findings suggest that vitamin D status in infancy, current vitamin D intake and season are predictors of vitamin D status in early school age children. Our finding of vitamin D status tracking from infancy to childhood provides motivation for further studies on tracking and its clinical significance.     

Prepregnancy obesity predicts poor vitamin D status in mothers and their neonates

Obesity is a risk factor for vitamin D deficiency, but this relation has not been studied among pregnant women, who must sustain their own vitamin D stores as well as those of their fetuses. Our objective was to assess the effect of prepregnancy BMI on maternal and newborn 25-hydroxyvitamin D [25(OH)D] concentrations. Serum 25(OH)D was measured at 4-21 wk gestation and predelivery in 200 white and 200 black pregnant women and in their neonates' cord blood. We used multivariable logistic regression models to assess the independent association between BMI and the odds of vitamin D deficiency [25(OH)D <50 nmol/L] after adjustment for race/ethnicity, season, gestational age, multivitamin use, physical activity, and maternal age. Compared with lean women (BMI <25), pregravid obese women (BMI >or=30) had lower adjusted mean serum 25(OH)D concentrations at 4-22 wk (56.5 vs. 62.7 nmol/L; P < 0.05) and a higher prevalence vitamin D deficiency (61 vs. 36%; P < 0.01). Vitamin D status of neonates born to obese mothers was poorer than neonates of lean mothers (adjusted mean, 50.1 vs. 56.3 nmol/L; P < 0.05). There was a dose-response trend between prepregnancy BMI and vitamin D deficiency. An increase in BMI from 22 to 34 was associated with 2-fold (95% CI: 1.2, 3.6) and 2.1-fold (1.2, 3.8) increases in the odds of mid-pregnancy and neonatal vitamin D deficiency, respectively. The rise in maternal obesity highlights that maternal and newborn vitamin D deficiency will continue to be a serious public health problem until steps are taken to identify and treat low 25(OH)D.     

An association of serum vitamin D concentrations < 40 nmol/L with acute respiratory tract infection in young Finnish men

BACKGROUND: The effects of vitamin D in regulating bone mineralization are well documented. The action of vitamin D as a key link between Toll-like receptor activation and antibacterial responses in innate immunity has recently been shown. The data suggest that differences in the ability of human populations to produce vitamin D may contribute to susceptibility to microbial infection. OBJECTIVE: We aimed to explore whether an association exists between vitamin D insufficiency and acute respiratory tract infection in young Finnish men. DESIGN: Young Finnish men (n = 800) serving on a military base in Finland were enrolled for this study. Their serum 25-hydroxyvitamin [25(OH)D] concentrations were measured in July 2002. They were followed for 6 mo, and the number of days of absence from duty due to respiratory infection were counted. RESULTS: The mean (+/- SD) serum 25(OH)D concentrations were 80.2 +/- 29.3 nmol/L (n = 756). Subjects with serum 25(OH)D concentrations < 40 nmol/L (n = 24) had significantly (P = 0.004) more days of absence from duty due to respiratory infection (median: 4; quartile 1-quartile 3: 2-6) than did control subjects (2; 0-4; n = 628; incidence rate ratio 1.63; 95% CI: 1.15, 2.24). We found a significant (P = 0.004) association between serum 25(OH)D concentrations and the amount of physical exercise before induction into military service. We also found significantly (P < 0.001) lower serum 25(OH)D concentrations in subjects who smoked (72.8 +/- 26.6 nmol/L; n = 192) than in control subjects (82.9 +/- 29.7 nmol/L; n = 537). CONCLUSION: Clinical trials of vitamin D supplementation are needed to investigate whether it enhances immunity to microbial infections.     

Prevalence and Determinants of Vitamin D Deficiency in 1825 Cape Town Primary Schoolchildren: A Cross-Sectional Study

Vitamin D deficiency (25-hydroxyvitamin D[25(OH)D] <50 nmol/L) is common among adults in Cape Town, South Africa, but studies investigating vitamin D status of children in this setting are lacking. We conducted a cross-sectional study to determine the prevalence and determinants of vitamin D deficiency in 1825 Cape Town schoolchildren aged 6–11 years. Prevalence of vitamin D deficiency was 7.6% (95% Confidence Interval [CI] 6.5% to 8.9%). Determinants of vitamin D deficiency included month of sampling (adjusted odds ratio [aOR] for July–September vs. January–March 10.69, 95% CI 5.02 to 22.77; aOR for October–December vs. January–March 6.73, 95% CI 2.82 to 16.08), older age (aOR 1.25 per increasing year, 95% CI: 1.01–1.53) and higher body mass index (BMI; aOR 1.24 per unit increase in BMI-for-age Z-score, 95% CI: 1.03–1.49). In a subset of 370 participants in whom parathyroid hormone (PTH) concentrations were measured; these were inversely related to serum 25(OH)D concentrations (p < 0.001). However, no association between participants with hyperparathyroidism (PTH >6.9 pmol/L) and vitamin D deficiency was seen (p = 0.42). In conclusion, we report that season is the major determinant of vitamin D status among Cape Town primary schoolchildren, with prevalence of vitamin D deficiency ranging from 1.4% in January–March to 22.8% in July–September.