Obese Children Crisis, Early Puberty, Increased Oestrogen and Testosterone, Aggressive Young Boys

By Ina Woolcott

Girls who are obese (over weight) at age 4 are far more likely to reach puberty before their 10th birthday. These findings have their routes in a study, which predicts that puberty will come earlier as the child obesity crisis worsens. The study, which is the first to track children from when they were toddlers to the age of 12, establishes a firm link between childhood obesity and an early start puberty.

The findings will add to pressure on governments to tackle the rise in children obesity. The American researchers admonish that the obesity crisis is now affecting children's development, while British experts say the trend will follow in Britain as childhood obesity reaches US levels.

Joyce Lee, an assistant professor of paediatric endocrinology at the University of Michigan, and lead researcher on the study, stated "This is a crucial study because it is the first longitudinal study to follow girls from 36 months to age of 12. We witnessed early onset puberty at 9 among those who were obese by the age of four. Before, it's not been clear whether girls are obese because they are hitting puberty earlier or hitting puberty early because they are obese."

"Early puberty is associated with increased psychological and social problems, early alcohol consumption and smoking. There can be long-term implications for the children."

The research, published in American journal Paediatrics, studied 400 girls, keeping records of weight and early signs of puberty. The monitoring included breast development and the start of the menstrual cycle. Circa 30% of the children were overweight or obese at the age of 9.

Scores at all ages of a higher body mass index (BMI), the calculation of weight using height measurements, were found to have a strong link with an earlier beginning of puberty in girls. For every extra point on the girls' BMI scores at 36 months, the odds of having earlier puberty rose by 44%.

In Australia, Boyd Swinburn, a professor of population health at Deakin University, said that the findings confirmed what paediatricians already knew about obesity's effect on stimulating the early onset of growth spurts and puberty. "It sounds like the new piece of evidence is they're able to predict it from the age of 4, and particularly for girls. The fat tissue is a source of female hormones. So a lot of fat tissue will increase the amount of oestrogen available and that is certainly a likely explanation for girls."

Professor Swinburn also said overweight, obese children can also go through "a rather precocious" growth spurt, a contributing factor to the early onset of puberty. They are more likely to be taller in the earlier years, but this doesn't influence their final height.

He said early puberty brought about other issues. Early periods could be traumatic for young girls. As for boys, being very big and having a burst of testosterone with puberty might trigger aggression.