BOSTON, Jan 9: People born with fewer microscopic filters in their kidneys may face a greater risk of high blood pressure when they get older, researchers said on Wednesday.

The findings, based on a study in Germany, may explain why people who receive a kidney transplant often develop the same pattern of blood pressure as the donor — and they also may give pregnant women an added reason to watch their diets.

The kidney, which cleanses the blood, is composed of hundreds of thousands of tiny filters called glomeruli.

Researchers said they studied 10 middle-aged people with high blood pressure and found they had a median of about 700,000 glomeruli in each kidney. That compared to a median of more than 1,400,000 of the small filters in the kidneys of 10 people with normal blood pressure.

All 20 of those studied had died in accidents.

Study coauthor Kerstin Amann of the University of Erlangen-Nurnberg told Reuters that even in very old patients who had normal blood pressure but whose kidneys showed heavy signs of wear-and-tear, the number of glomeruli was not much lower than in younger patients with high blood pressure.

The researchers also found that the glomeruli of people with high blood pressure were larger, an indication that each filter was being forced to work harder.

Julie Ingelfinger, an editor of the New England Journal of Medicine, which published the study in its Thursday edition, said the findings may give pregnant women another reason to watch what they eat.

Not eating enough protein, for example, may produce a baby with fewer kidney filters. Over time, the ability of the kidney to overcompensate for the dearth of glomeruli may falter and high blood pressure could result.—Reuters