Clothing type and vitamin D status: a systematic review and meta-analysis

Abstract

Background Inconsistent reports have been made on the link of clothing style to vitamin D deficiency (VDD). However, there is no meta-analysis report on the link. Thus, we pooled the existing empirical evidence on the association of wearing concealing clothing with VDD and serum 25(OH)D level among healthy adult women. Method PubMed, Embase, Scopus, Web of Sciences, and Google Scholar were searched for studies published until December 15, 2020 on the relation of clothing type with vitamin D status. Odds ratio (OR) and standardized mean difference (SMD) were used to summarize the estimates on the association of concealing clothing with VDD status and 25(OH)D level, respectively. The summary estimates were calculated with random-effects meta-analyses, with heterogeneity assessed by I2–metrics and subgroup analyses done by types of clothing and regions of residence. Result In total, 14 studies with a total of 11,332 individual participants were included. Overall, women who wear concealing clothing were 2.28 times more likely to develop VDD compared with women who do not wear concealing clothing (pooled OR=2.28, 95%CI=1.67, 3.10, P<0.001). The summary odds of VDD was 1.36 times higher among women who wear veil hijab compared with women who do not wear veil hijab (95%CI=1.49, 3.59, P<0.001). The summary odds of VDD was 2.25 times higher among women who wear long sleeve clothes compared with those who wear short sleeve clothes (95%CI=1.63, 3.11, P<0.001). The mean serum 25(OH)D level of women who wear veil hijab was also significantly lower by 6.48 ng/ml (pooled SMD= -6.48, 95%CI= -8.24, -4.73, P<0.001). Conclusion Clothing type, particularly fully concealing clothes like hijab, might be contributing to the burden of VDD. Further studies are warranted to investigate the role and dose of additional VD supplement to compensate the effect of concealing clothing (hijab) on VD status of women