Some people appear to be born at risk for high blood pressure, with far fewer filters than normal in their kidneys, a study found.
Doctors do not know how big a role is played by this kidney condition, which occurs when a mother doesn't eat enough protein. Nevertheless, the small German study raises the possibility that for some, susceptibility to high blood pressure begins before birth.
Dr. Leslie Spry, a spokesman for the National Kidney Foundation, said the study offers the first anatomic evidence in people to back up a long-standing theory.
"I would have been a little bit of a doubter that they would find something like this," Spry said. But "it's very carefully done, very carefully documented, and it's quite believable."
The study, which appears in today's New England Journal of Medicine, was conducted by Kerstin Amann of the University of Erlangen-Nurnberg, and colleagues there and at the University of Heidelberg and City Hospital of Darmstadt.
The researchers found 10 men who had died in accidents and had had high blood pressure.
Each was matched with another accident victim of the same age, sex, height and weight who had not shown any sign of hypertension.
Painstaking counts found that the kidneys of the healthier people had two to three times more filters -- twisted masses of blood vessels called glomeruli -- than their counterparts with high blood pressure.
Spry said he would like to see a similar study among blacks, who for unknown reasons are more likely than whites to have high blood pressure.
Amann said the findings also highlight the importance of diet during pregnancy.