Birth weight, weight gain tied to early puberty

A relatively low birth weight and early-age weight gain increases the likelihood of early puberty.

Earlier onset of puberty has been linked to certain cancers, high blood sugar and obesity. To investigate whether early life exposures influence the timing of puberty, researchers identified 215 boys and girls who were part of an ongoing nutrition and growth study begun in 1985 by the Research Institute of Child Nutrition in Dortmund, Germany. For these youngsters, researchers had complete information on birth age and size, and had at least 5 weight and height measurements recorded between the ages of 6 and 13 years. From these measurements, the researchers determined that 53 children began their pre-pubertal growth spurt at an earlier age, 108 at a normal age, and 54 at a later age.

In the earlier puberty age group, nearly 21 percent had a low birth weight; they weighed between 2.4 and 2.9 kg at birth. (A normal birth weight is about 3.4 kg). By contrast, similar low birth weight occurred in only 10 percent of the normal puberty age group and just under 6 percent of the later puberty age group. In addition, about 42 percent of the earlier age group, versus about 20 and 19 percent of the normal and later groups, had rapid weight gain from birth through the age of 2 years.

The findings suggested the onset of puberty may occur from 4 to 7 months earlier among boys and girls who weighed less than normal at birth and among those who rapidly gained weight from birth through the age of 2 years.

Further investigations are needed to identify the mechanisms by which birth and early life factors affect puberty onset, particularly in light of the increased risk for breast and testicular cancers, blood sugar disorders, and obesity associated with earlier puberty.