Female Pubertal Development in the United Kingdom: Trends in Onset, Progress and Duration from 1948 to the Present

Abstract

Female pubertal development is the process of physical changes from the child to adult female bodies. The nature of human adaptation creates huge inter and intra-population variation in female pubertal development in response to both heritable and environmental determinants.
Age at menarche has been declining globally in response to urbanisation and industrialisation. In the USA and other developed countries age at pubertal onset, specifically age at thelarche, appears to be declining with the concurrent rise in overweight and obesity.
Longitudinal cohort datasets from the UK were analysed to replicate these findings in the UK population from 1948-2005. These data show evidence for a continued downward secular trend in age at menarche, and show a downward secular trend in age at pubertal onset, in response to increased weight status. Over the period 1948-2005, age at menarche decreased by 0.30 years, and age at thelarche decreased by one year. The average interval between pubertal onset and age at menarche increased from 2.3 years to 2.7 years. More than half of the total decrease in age at thelarche took place between 1980 and 2001.
Some of the variance in pubertal development, and specifically the large decrease in age at thelarche, may to be the result of increasing exposure to endocrine disrupting chemicals over the last 50-60 years. Lipophilic endocrine disruptors have the potential to accelerate pubertal development in overweight girls who have the capacity to store dangerous levels of these toxic substances in their high fat mass.
The changes in timing and tempo of female pubertal development in the UK should be considered on a continuum of adaptive plasticity that is evident in the population variation of female pubertal development, rather than measuring recent changes as pathology.
Earlier age at puberty has a number of implications for negative health outcomes, specifically increased risk of reproductive cancers. Moreover, the interaction between increased weight status and increased exposure to endocrine disruptors may exacerbate these negative effects.