Early puberty exposes women to a higher risk of obesity in adulthood and would be a risk factor in its own right along with diet or education, suggests a study published in the International Journal of Obesity.
Social pressures on physically more mature girls may explain risks of obesity in adulthood.
Women who have reached puberty before the age of 12 are more likely to be overweight, due to early hormonal changes, according to a research conducted by researchers at Imperial College London published in the International Journal of Obesity.
The researchers used a technique called “Mendelian Randomization” which is used to identify risk factors – such as cardiovascular disease – based on genetics to establish this cause-and-effect relationship. This genetic analysis has eliminated other criteria that may influence weight gain in adulthood such as ethnicity, level of education, economic context and diet, the study said.
Of the 182,416 women selected for this work, the researchers identified 122 genetic variants associated with the onset of puberty and first menses. They then looked at data from another panel of 80,465 women registered in the UK Biobank, a British medical database, to assess the effect of precocious puberty on body mass index (BMI).
They found that girls who started puberty earlier, before the age of 12 on average, were more likely to be obese than those who had their menses later.
This link of cause and effect was confirmed on a third group of 70,962 women, according to the study which notes a decrease in BMI of the order of 0.38kg /m2 for each year delayed by the onset of menstruation.
Psychological factors such as differential treatment and social pressures on physically older girls may explain this causal link, the study suggests.
Physiologically, the authors of the study discuss the hormonal changes associated with puberty such as early chest thrust, which may constitute an increase risk of high body mass index (BMI) or obesity later in life.