In the largest study of its kind to date, the timing of puberty was found to have a wide range of impacts on health in later life.
Researchers from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge found that the age at which both men and women begin puberty is associated with 48 different health conditions.
The study, published today in Scientific Reports, confirms previous findings that early puberty in women is a risk factor for heart disease and type 2 diabetes, and showed, for the first time, that early puberty in men also influences these same conditions.
In addition, new links were found between the timing of puberty and a wider range of health conditions, including irritable bowel syndrome, arthritis, glaucoma, psoriasis and depression in men and women, and also early menopause in women.
Researchers tested data from nearly half a million people in UK Biobank, a national study for health research funded primarily by the MRC and the Wellcome Trust. Participants have undergone a range of measures, provided blood, urine and saliva samples for future analysis, detailed information about themselves and agreed to have their health followed.
As part of the information they provided, UK Biobank participants were asked to recall puberty-timing by remembering the age of their first monthly period for women and age at voice-breaking for men. The timing of puberty varies significantly between individuals, with the normal onset of puberty ranging from 8 to 13 in girls and from 9 to 14 in boys.
Those in the earliest or latest 20% to go through puberty had higher risks for late life disease when compared to those in the middle 20%. For example both men and women who went through puberty relatively early had around 50% higher relative risks for type 2 diabetes and heart disease, while both women and men who went through puberty relatively late had a higher relative risk of developing asthma.
Conversely some findings differed between women and men, for example women who were in the latest 20% to go through puberty had higher relative risk of heart disease, whereas men who went through puberty relatively late had a relatively lower risk of heart disease. Furthermore, many of these 48 disease links were not simply explained by socioeconomic status and obesity.
It was previously thought that only those individuals with relatively early puberty were more susceptible to a handful of specific diseases.
Dr Felix Day, lead author of the study at the MRC Epidemiology Unit, said:
Up until now, the link between early puberty and risk of disease has been blamed on weight and obesity, but our findings suggest that men and women of a normal weight who go through puberty relatively early or late may also carry these risks.
Though a cross-sectional study of this kind cannot distinguish between cause and effect, evidence from other studies using different methods does point to a causal link between puberty and certain diseases, such as type 2 diabetes. In other cases it may be that puberty is acting as a marker of underlying genetics associated with certain diseases, and in a few cases it may be that the disease itself starts early in life and then affects puberty timing.”
Dr John Perry, Senior Investigator Scientist at the MRC Epidemiology Unit, added:
We are continuing to work to understand how puberty timing impacts later health and how this information may be used alongside efforts to support healthy lifestyle changes and prevent disease.
It is important to note that the increase in disease risk attributable to puberty timing is still relatively modest and represents one of many factors that contribute to the overall risk of developing disease.”
In their paper in Scientific Reports the authors stress that:
Our findings do not indicate that avoidance or treatment of abnormal puberty timing will invariably have widespread beneficial consequences, but rather further work is needed to understand the possible psychosocial, adiposity-related and adiposity-independent mechanisms that link puberty timing to later life health outcomes.”
The authors note that their consideration of a wide range of potential adverse health outcomes raised the possibility of spurious associations arising out of multiple testing. To minimize this possibility, they set a highly conservative statistical threshold, and the very large sample size of the Biobank cohort also allowed the size of the effect of puberty timing to be determined with greater precision and accuracy. They also acknowledge that their study design relies on self-reporting of puberty timing and health status, though previous studies in women indicate that errors in recalling the timing of their first monthly period are not influenced by subsequent health status, and so are unlikely to affect the results reported in their paper. While timing of voice breaking in men has been found in prospective studies in boys to be an accurate measure of puberty, it has not been validated by recall in adult men.
The research was funded by the Medical Research Council.
Felix R. Day, Cathy E. Elks, Anna M. Murray, Ken K. Ong and John R.B. Perry “Puberty timing associated with diabetes, cardiovascular disease and also diverse health outcomes in men and women: the UK Biobank study” Scientific Reports. Published Online 18 June 2015. (Open access)