Ten-year findings from the Puberty Cohort: a sub-cohort within the Danish National Birth Cohort

The age of puberty is declining. Earlier puberty has major implications due to associations with later physiological and psychiatric morbidities. Therefore, the identification of potential modifiable risk factors is warranted. The Puberty Cohort, nested within the Danish National Birth Cohort (DNBC), was set up to identify the causes and consequences of earlier puberty and to establish whether age at puberty is still declining.

The DNBC Puberty Cohort consists of 15 819 live-born singletons (8123 girls and 7696 boys) born in 2000-03. From 2012 to 2021, they provided information on several pubertal milestones half-yearly from ages 11 to 18 years. In this review, we present the results from the studies conducted in the DNBC Puberty Cohort so far addressing the importance of prenatal and childhood biological and psychosocial factors.

Age at puberty is still declining among Danish girls and boys. Several risk factors for earlier puberty have been identified, including familial predisposition, childhood overweight and obesity, maternal smoking in the first trimester, several maternal gestational diseases, as well as psychosocial exposures. The mentioned exposures were associated with earlier puberty of ≤4-5 months in both girls and boys. Other exposures studied showed either weaker or no association with earlier puberty, but for some also later puberty.

Ten years of research within the unique DNBC Puberty Cohort has identified several prenatal and childhood biological and psychosocial factors associated with earlier puberty, including potential targets for intervention both during pregnancy and in childhood.