FRIDAY, Oct. 10, 2003 (HealthDayNews) -- Here's some advice from a long-running British study: If your father was a working class man and your birth weight was low, be scrupulous in watching your weight and keeping your blood pressure under control.
Researchers who took more than 3,600 Britons who were born in 1946 and followed them until 1999 found those whose birth weight was below average and whose parents performed manual labor tended to have high blood pressure in their 30s. They were much more likely to be obese, a major cause of high blood pressure. The report appears in the Oct. 11 issue of The Lancet.
The link between birth weight and adult high blood pressure has been controversial, says study leader Rebecca Hardy, a statistician at University College London. Previous studies have produced conflicting results.
One important aspect of this latest one is that it followed a large number of people for many years, the researchers say. "Most studies with repeated measures of blood pressure were done through childhood and adolescence," the journal report says. This study followed the participants into their 50s.
Also new is the suggestion that the socioeconomic status of a newborn baby can affect blood pressure decades later.
"One can only speculate why," Hardy says. "One possibility is that it is the result of how you are brought up in childhood, a poorer diet and things of that sort."
As for low birth weight, researchers have speculated that a poor environment in the womb hinders the growth of a fetus and somehow damages the body's natural blood pressure control mechanism.
The definition of socioeconomic status used in the study was simple; the participants were asked if their parents did manual labor. But somehow the effects of that labor became increasingly evident with the years.
All low birth weight children tended to have higher than average blood pressure at the age of 36, the researchers found. But for those whose parents did manual labor, there was a continued increase in blood pressure up to age 53, when the last measurements were done, Hardy says.
"The effects of early social class are getting larger," she says.
The finding makes sense, says Dr. William T. Gilbert, a professor of obstetrics and gynecology at the University of California at Davis, who has done his own research on low birth weight and high blood pressure.
"If you grow up in a working class environment, you are subjected to great social and environmental stresses," he says.
But both Hardy and Gilbert say birth status is not an inevitable and unmanageable cause of obesity, high blood pressure and all the medical problems that accompany them.
"The fact that the highest risk factor is obesity strengthens the point that what we do in the here and now is important for preventing high blood pressure and the complications of high blood pressure," Gilbert says.
"I would suggest that we can start earlier in life to reduce the risks," Hardy says.
The controllable causes of high blood pressure and what can be done about them are outlined by the American Heart Association. The National Heart, Lung, and Blood Institute also has tips on preventing high blood pressure.