Early puberty may raise type 2 diabetes risk in women
medwireNews: Earlier age at menarche (AAM) is associated with an increased risk for type 2 diabetes and impaired glucose tolerance (IGT) among women, and this association remains significant after adjustment for adiposity, suggest findings from a meta-analysis.
As reported in PLOS Medicine, the meta-analysis included 28 observational studies, comprising over a million people in total, all of which assessed AAM in women. The majority of studies (n=13) involved Asian people, followed by White (n=9) and multi-ethnic (n=6) populations.
When AAM was assessed as a continuous variable, people with older AAM had a lower risk for type 2 diabetes or IGT, with a significant risk ratio (RR) of 0.91 for each additional year. This inverse association was attenuated, but remained statistically significant, after adjustment for adiposity, at a RR of 0.97 for each additional year.
Similarly, when participants were categorized according to whether they experienced early menarche or not, defined using cutoffs of 12 or 14 years in the included studies, there was a significant association between early menarche and elevated risk for diabetes or IGT (RR=1.39), which remained significant, albeit weaker, when accounting for adiposity (RR=1.19).
Tuck Seng Cheng and co-authors, from the University of Cambridge in the UK, note that the associations between older AAM and diabetes or IGT were stronger among White than Asian women. The RRs per each additional year at menarche were 0.88 and 0.95 for White and Asian women, respectively, in the unadjusted analysis, and 0.95 and 0.98, respectively, after adjustment for adiposity. The corresponding RRs for early versus later menarche were 1.72 and 1.33 before adjustment, and 1.27 and 1.23 after adjustment.
The researchers then combined RRs from their meta-analysis with UK Biobank data on the prevalence of early menarche in White British women, and estimated that the population-attributable risk for type 2 diabetes or IGT due to menarche before the age of 12 years was 12.6% before accounting for adiposity and 5.1% after adjustment.
These findings suggest “that a substantial proportion of [type 2 diabetes] cases in UK women was related to early menarche, and we would expect this proportion to increase in light of global secular trends towards earlier puberty timing,” remark the investigators.
They say that the mechanisms underlying the observed associations are “unclear,” noting that both adiposity-dependent and -independent pathways are likely involved, and sex hormone exposure could play a role.
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