Is age of menarche directly related to vitamin D levels?

Abstract

Introduction Very few studies have examined the direct link between age of menarche and vitamin D level and controversial results have been reported. This study aimed to investigate the association between vitamin D and age of menarche in a group of adolescent girls in an area with plenty of sunshine. Methods At baseline, data were collected on 722 middle schoolgirls that were randomly selected by probability proportional to size sampling method. Of this group, 598 were followed including 173 who had their menarche during the follow‐up. Serum 25‐hydroxyvitamin D (25OHD) was measured at baseline using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). Data on potential confounders were collected at baseline from the parents using self‐administered questionnaire and from schoolgirls through face‐to‐face interview. Multiple linear regression and time‐to‐event analysis were used to investigate the association between 25OHD concentration and age of menarche. Results The mean (SD) age of the study group was 12.51 (0.91) years while the main (SD) age of menarche was 11.82 (1.04) years. The prevalence of vitamin D deficiency (<50 nmol/L) among schoolgirls was 91.69%. We found no evidence for the association between 25OHD levels and age of menarche before (β, .00, 95% confidence interval (CI) [−0.01, 0.01]; p = .808) or after (β, .00, 95% CI [−0.01, 0.01]; p = .765) adjusting for potential confounders. We also found no evidence for association between 25OHD status and age of menarche before (p = .424) or after (p = .356) adjusting for potential confounders. Time‐to‐event analysis showed no association between 25OHD level or status and age of menarche (p = .850). Conclusion In Middle Eastern setting, where vitamin D deficiency is common despite plenty of sunshine, vitamin D is not a major determinant of the age at menarche. Regardless of the link between vitamin D and age of menarche, there are several other health benefits of having adequate vitamin D level during childhood and adolescence.

Association between Vitamin D Levels, Puberty Timing, and Age at Menarche

“…Al-Taiar et al [77] reported the association between 25OHD levels and age of menarche in Kuwait with a cross-sectional study and a prospective cohort study on 722 middleschool girls while also adjusting for potential confounders such as BMI, waist-height ratio, physical activity, and socioeconomic factors [77]. Even in this study, in which just the "severe deficiency category" was considered, no significant correlations between age of menarche and 25OHD status were observed [77]. The different results reported in the above-mentioned studies, performed in very different ethnic groups, might be secondary to the variability in human VDR gene polymorphisms that has been observed in different populations [78].…”

“…Only a few studies in the literature itself have examined the association between vitamin D status and age of menarche [71,76,77].…”

“…Since vitamin D is fat-soluble, and therefore sequestered within the excessive adipose tissue, given the documented earlier menarche in girls with overweight or obesity [82], an effect of vitamin D levels on age at menarche has been speculated [77]. An effect of low vitamin D concentration on EM development may also be present.…”