http://www.msnbc.msn.com/id/20776223/wid/11915773?GT1=10412
Teens’ unhealthy weight affects later fertility
Being underweight or obese results in fewer kids in adulthood, study finds
Reuters
Updated: 12:03 p.m. MT Sept 14, 2007
NEW YORK - Teenagers who are either underweight or obese are likely to have
fewer children in adulthood, a study has found.
It’s known that both obesity and abnormally low body weight are related to
reproductive difficulties, and that obesity raises the risk of a number of
pregnancy complications. However, it has not been clear whether underweight
and obese teenagers go on to have fewer children than their normal-weight
peers.
For the new study, researchers used data on nearly 1,300 Finnish men and
women who were part of a larger study that has tracked their health since
1980. All were between the ages of 3 and 18 at the study’s outset, and had
their body mass index (BMI) measured in adolescence.
The researchers report the findings in the medical journal Epidemiology.
Overall, adults who had been underweight as teenagers had 10 percent to 16
percent fewer children, compared with those who had a normal BMI in
adolescence. Men and women who’d been obese as teens had 32 percent to 38
percent fewer children.
“We know a lot about (the) correlation between BMI and fertility in
adulthood,” study co-author Dr. Liisa Keltikangas-Jarvinen, of the
University of Helsinki, told Reuters Health.
In this study, she explained, there was a long-term effect of teenage BMI,
independent of adulthood BMI. This was particularly true of women.
For women, an abnormally low BMI can disrupt the menstrual cycle, while
obesity can lead to fertility problems. Obesity can, for example,
contribute to polycystic ovary syndrome, a cause of infertility.
A man’s reproductive health can also be affected by weight. Both obesity
and a low BMI have been linked to poor sperm quality, and obesity can raise
the risk of erectile dysfunction.
In this study, underweight and obese teenagers were also less likely than
their normal-weight peers to live with a partner in adulthood — a
difference that partially explained why they had fewer children.
Given the increase in obesity rates around the world, the researchers note,
the current findings suggest there could be widespread effects on adults’
reproductive health.
In particular, Keltikangas-Jarvinen said, the results ”stress” the
potential long-term effects of obesity at a young age — offering one more
reason to prevent excessive weight gain in childhood.