Childhood obesity may cause early puberty

The study by the University of Michigan's Mott Children's Hospital following a group of 354 girls and found that those who were fatter at age 3 and gained weight during the next three years reached puberty, as defined by breast development, by age 9.

Earlier studies have found that US girls are reaching puberty earlier than was the case 30 years ago, a time span during which rates of childhood obesity also increased, the study said.

The researchers said that 168 of the girls were classified as being "in puberty" by the age of 9 and nearly two dozen reported having their first menstrual period by two years later.

"Earlier onset of puberty in girls has been associated with a number of adverse outcomes, including psychiatric disorders and deficits in psychosocial functioning, earlier initiation of alcohol use, sexual intercourse and teenage pregnancy and increased rates of adult obesity and reproductive cancers," the study said.