Prevalence and Determinants of Vitamin D Deficiency in 9595 Mongolian Schoolchildren: A Cross-Sectional Study

Abstract

Population-based data relating to vitamin D status of children in Northeast Asia are lacking. We conducted a cross-sectional study to determine the prevalence and determinants of vitamin D deficiency in 9595 schoolchildren aged 6–13 years in Ulaanbaatar (UB), the capital city of Mongolia. Risk factors for vitamin D deficiency were collected by questionnaire, and serum 25-hydroxyvitamin D (25[OH]D) concentrations were measured using an enzyme-linked fluorescent assay, standardized and categorized as deficient (25[OH]D <10 ng/mL) or not. Odds ratios for associations between independent variables and risk of vitamin D deficiency were calculated using multivariate analysis with adjustment for potential confounders. The prevalence of vitamins D deficiency was 40.6% (95% CI 39.7% to 41.6%). It was independently associated with female gender (adjusted odds ratio [aOR] for girls vs. boys 1.23, 95% CI 1.11–1.35), month of sampling (aORs for December–February vs. June–November 5.28 [4.53–6.15], March–May vs. June–November 14.85 [12.46–17.74]), lower levels of parental education (P for trend <0.001), lower frequency of egg consumption (P for trend <0.001), active tuberculosis (aOR 1.40 [1.03–1.94]), household smoking (aOR 1.13 [1.02 to1.25]), and shorter time outdoors (P for trend <0.001). We report a very high prevalence of vitamin D deficiency among Mongolian schoolchildren, which requires addressing as a public health priority.

Influence of vitamin D supplementation on muscle strength and exercise capacity in South African schoolchildren: a randomised controlled trial (ViDiKids)

“…32–35 Our finding of a small borderline-significant positive effect of vitamin D supplementation on long jump distance supports the concept that vitamin D has a physiological role in supporting muscle strength. 5 However, the fact that this was not associated with an effect on grip strength, plus the observation that no such effect was seen in Mongolian children (who had a significantly higher baseline prevalence of vitamin D deficiency than participants in the current study) 10 11 suggests that this result may have arisen as a result of type 1 error arising as a result of investigating multiple secondary outcomes. The other borderline-significant finding was in the opposite direction to that anticipated: vitamin D supplementation associated with an increased risk of EIB at 3-year follow-up, in contrast to expectations that the intervention would reduce this risk via its immunoregulatory actions.…”

“…[5][6][7] Deficiency in this fat-soluble micronutrient -indicated by low circulating concentrations of 25-hydroxyvitamin D (25[OH]D) -is widespread among children in both higher-and lower-income countries. [8][9][10][11] Observational studies have linked vitamin D deficiency in children and adolescents to reduced muscle strength and cardiorespiratory fitness, 12 13 and increased risk of exercise induced bronchoconstriction (EIB), 14 which may limit exercise capacity. Numerous randomised controlled trials (RCTs) in adults have revealed positive effects of vitamin D supplementation on muscle strength and power, with meta-analyses reporting a modest benefit overall.…”

Adequate 25(OH)D moderates the relationship between dietary inflammatory potential and cardiovascular health risk during the second trimester of pregnancy

“…Hence, inflammatory status of individuals cannot be evaluated comprehensively. Moreover, a caution should be taken when interpreting this study results, since previous studies (32)(33)(34)(35)(36)(37) have shown that components of the CVR score in this study (BMI, blood pressure, total cholesterol, glucose levels, and smoking status, and also triglyceride levels) are in inverse association with vitamin D levels, and therefore, a higher CVR score should be automatically associated with lower vitamin D levels in our study. To sum, our research was conducted only on the pregnant Chinese women.…”

Multiple Sclerosis in Mongolia; the First Study Exploring Predictors of Disability and Depression in Mongolian MS Patients

“…Although sun exposure and vitamin D may have independent risk factors for CNS demyelination [ 63 ], a recent meta-analysis reported [ 64 ] a significant association between low vitamin D and increased risk of developing MS. Although a high prevalence of vitamin D deficiency has been reported in Mongolia [ 65 ], serum vitamin D levels in MS patients were not performed in our current study.…”