Pubertal timing and adult obesity and cardiometabolic risk in women and men: a systematic review and meta-analysis.

Obesity has complex multifactorial aetiology. It has been suggested by many, but not all, reports that earlier pubertal maturation may increase adult obesity risk. We conducted a systemic review and meta-analysis in both women and men, and hypothesised that any association between pubertal timing and adult obesity is likely to be confounded by childhood adiposity. In addition, we investigated whether pubertal timing is related to other cardiometabolic risk and long-term cardiovascular morbidity/mortality. Literature search was undertaken using MEDLINE, EMBASE, Web of Knowledge and TRIP databases, with a hand search of references. Both authors independently reviewed and extracted pre-defined data from all selected papers. Meta-analyses were conducted using Review Manager (RevMan) 5.0.24. A total of 48 papers were identified. Out of 34 studies, 30 reported an inverse relationship between pubertal timing and adult body mass index (BMI), the main adiposity measure used. Meta-analysis of 10 cohorts showed association between early menarche (menarche <12 vs ≥12 years) and increased adult BMI, with a standardised mean difference of 0.34 kg m(-2) (95% confidence interval: 0.33-0.34). Heterogeneity was large (I(2)=92%) but reduced significantly when grouped by outcome age. Late menarche (menarche ≥15 vs <15 years) was associated with decreased adult BMI, with a standardised mean difference of -0.26 kg m(-2) (95% confidence interval: -0.36, -0.21) (seven cohorts). Only eight papers included data on childhood BMI; the majority reported that childhood BMI only partially attenuated association between early menarche and later obesity. Although not suitable for meta-analysis, data on cardiometabolic risk factors and puberty suggested negative association between earlier pubertal timing and cardiovascular mortality, hypertension, metabolic syndrome (MetS) and abnormal glycaemia. Earlier pubertal timing is predictive of higher adult BMI and greater risk of obesity. This effect appears to be partially independent of childhood BMI. Earlier pubertal development appears to also be inversely correlated with risk of other cardiometabolic risk factors and cardiovascular mortality. Further work is needed to examine potential mechanisms and the level at which interventions may be targeted.