Boys Lean at Birth May
Have Hypertension Risk
Excerpt By Ed Edelson, HealthScoutNews

How well a woman eats during her pregnancy might affect her son's risk of cardiovascular disease later in life, researchers say.

Some boys who are unusually thin at birth have an increased risk of high blood pressure when they grow up if they have an unusual growth spurt between ages 8 and 15, says a study in the Feb. 11 issue of Hypertension. And as-yet unpublished data from the same study shows the same relationship for cholesterol levels, says study author Linda S. Adair, professor of nutrition at the University of North Carolina.

However, the study contains a couple of mysteries, Adair says. The risk was not found for boys who had rapid growth in the first two years of life, and the relationship between body proportions at birth and elevated blood pressure at adolescence did not hold true for girls. Large weight gains for girls aged 8 to 15 was associated with high blood pressure, but the risk was not related to weight at birth.

"The sex difference is a big question that we cannot answer," Adair acknowledges.

The data came from the Cebu Longitudinal Health and Nutrition Survey, which is following more than 2,000 persons born in 1983 and 1984 in and near that Philippines city. They fit well with a fetal programming theory propounded by Dr. David J. P. Barker of the University of Southampton in England, she says -- that a malnourished fetus will adjust its metabolism to survive in the womb, but that adjustment might cause trouble later.

This not the first study to relate life in the womb to health later in life. Last month, British researchers reported that girls who were above average weight at birth were more likely to develop breast cancer before the menopause than girls of average weight.

The analysis of the Cebu data took into account all the factors that might affect blood pressure, and birth weight remained important, Adair says.

"The main point is that there is an interaction between being underweight at birth, rapid growth during childhood and adolescence, and cardiovascular risk factors later in life," Adair says. "It turns out that growth during infancy, in this study at least, was not a risk factor, but more rapid weight gain later in life was."

The lesson for parents of both boys and girls is "to optimize nutrition of the mother during pregnancy," Adair says. For boys who are putting on a lot of weight as they grow up, parents "should be more careful about their diet and exercise and other risk factors," she says.

"Unhappily, we don't know enough about how to prevent hypertension and obesity," she says.

However, we do know some basic measures, says Dr. Rae-Ellen Kavey, chief of cardiology at Children's Memorial Hospital of Northwestern University in Chicago and a spokeswoman for the American Heart Association. She agrees with Adair that the starting point is "good maternal-fetal care," including an adequate diet.

At any age, "excessive weight gain is no good," Kavey adds, and one obvious measure to avoid that is "control of overall food intake."

While the study has some limitations -- for example, it never defines high blood pressure -- it gives important information, Kavey says. "The boys who had the highest blood pressure weighed most at birth and put on the most weight later," she says, and they are the ones who need the most attention.

More information

Learn about obesity, its dangers and how to avoid it from the American Heart Association. If you're pregnant, get lessons on taking care of yourself and your baby from the March of Dimes.

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