High prevalence of vitamin D deficiency among the South Asian adults: A systematic review and meta-analysis

Abstract

Background: Vitamin D deficiency is linked to a wide range of chronic and infectious diseases. Body of literature suggested that the prevalence of this deficiency can have geographical variation. Although, vitamin D deficiency is frequently reported in the South Asian population, the scarcity of systematic reviews and meta-analyses means the true extent of the disease and the underlying factors causing it are poorly characterized.Methods: A systematic search was performed using databases (PubMed, Scopus and Google Scholar) for original studies on the South Asian population (published from January 1, 2001 to December 31, 2019). Following the search, a random effect meta-analyses was performed to calculate population level weighted average, pooled prevalence of deficiency, and heterogeneity of vitamin D among different countries and genders; in addition to South Asia as a whole.Results: Our study, based on our selection criteria was narrowed down to a total of 44,717 participants; that spanned over 65 studies from five South Asian countries. Overall, the pooled prevalence of deficiency was 68% [95% CI: 64% to 72%] with significant heterogeneity (I2 = 98%; p = 0.00). Average level of vitamin D ranged from 4.7 to 32 ng/mL, with a weighted mean of 19.15 ng/mL (weighted standard deviation 11.59 ng/mL). The highest prevalence of vitamin D deficiency was found in Pakistan (73%; 95% CI: 63% to 83%) followed by Bangladesh (67%; 95% CI: 50% to 83%), India (67%; 95% CI: 61% to 73%), Nepal (57%; 95% CI: 53% to 60%) and Sri Lanka (48%; 95% CI: 41% to 55%), respectively. This finding indicated a high degree of heterogeneity among the population. (I2 = 98.76%), Furthermore, a gender wise analysis suggested that in South Asia, the prevalence of vitamin D deficiency was higher in females than males. Conclusion: Our findings reveal highly prevalent and variable vitamin D deficiency among the adults of different South Asian countries. Findings from this review would be helpful to generate hypotheses and explore the factors affecting the inter-country variability, alongside strengthening evidence for governments to prioritize mitigation strategies in this region.

High burden of hypovitaminosis D among the children and adolescents in South Asia: A systematic review and meta-analysis

“…In our study, the age-wise analysis revealed that the prevalence of hypovitaminosis D is more among neonates (85%) than preschool (55%) and school-going children (57%) [Figure 5]. This may be associated with the high prevalence of vitamin D insu ciency (65%) among South Asian pregnant women which we have shown in one of our recent studies [75].…”

High prevalence of vitamin D insufficiency among South Asian pregnant women: a systematic review and meta-analysis

“…While all of the hypotheses proposed above could be contributing to the observed heterogeneity, slightly different cut off values (other than <20ng/mL) used by some of studies that were included in this systematic review 36,38,40,47,49,50,54 might have influenced the degree of heterogeneity in our analysis. However, such heterogeneity many not be uncommon as we have demonstrated in one of the similar studies on SA adult population 72 . However, it is clear that further study is required to reveal the true source and extent of heterogeneity.…”