BOSTON, April 24 Breastfeeding infants does not lower their risk of becoming overweight later in life, according to researchers at Harvard University in Boston.Study leader Karin B. Michels and colleagues assessed the health of 35,000 U.S. nurses working over a 12-year period from 1989 to 2001.The nurses' mothers were asked to report on their breastfeeding habits. After confounding socioeconomic factors were removed, the study found that being breastfed had no significant effect on the body mass index of the participants in adulthood. The results were published in the International Journal of Obesity.The study did find that children exclusively breastfed for more than six months have a somewhat leaner body shape at age 5, but this correlation did not continue into adolescence or adulthood, says Michels.The study contradicts guidance by the Centers for Disease Control and Prevention, which promotes breastfeeding as a strategy for controlling childhood obesity with the aim of preventing adolescent and adult obesity, according to the researchers.Copyright 2007 by UPI