Birth Control Pill, Urine Protein 
Linked to Kidney and Heart Disease

Lindsey Tanner / AP 9sep01

CHICAGO -- Dutch research links birth control pills and menopause hormone supplements with small amounts of protein in the urine that may signal an increased risk of kidney and heart disease.

Women who used either of the estrogen-based pills faced about double the risk of developing the urine protein condition, called microalbuminuria, compared with nonusers.

The increased risk was found in women who'd used either product within the year prior to having their urine tested. Women who used hormone supplements for more than five years faced the greatest risk, about 21/2 times that of nonusers, according to the study of 4,301 Dutch women in Monday's Archives of Internal Medicine.

While women weren't followed long enough to see if they developed kidney or heart disease, the findings support other research suggesting that long-term use of oral contraceptives or hormones at menopause may increase the risk for cardiovascular disease, said the authors, led by researcher Taco B.M. Monster of the University of Groningen.

Doctors not involved in the research stressed that the study is preliminary.

``These are provocative findings but they clearly need confirmation,'' said Dr. JoAnn Manson, chief of preventive medicine at Harvard University's Brigham and Women's Hospital. ``It certainly doesn't prove cause and effect.''

Protein in the urine is thought to be an early sign of kidney disease, suggesting a defect in the kidneys' filtering ability allowing protein to leak from the blood into the urine. Recent, very preliminary studies also have suggested that it may be associated with an increased heart disease risk, perhaps suggesting a vascular problem that results in the veins leaking blood, said Dr. Nieca Goldberg, chief of the women's heart program at Lenox Hill Hospital in New York and an American Heart Association spokeswoman.

The Dutch study found women who used either of the estrogen-based pills were more likely to develop a mild form of the condition in which an average of 30 to 300 milligrams of protein was found in two separate 24-hour urine tests.

Birth control pills taken by women in the study contained estrogen and progestin and hormone supplements contained estrogen with or without progestin. Both types of products were identical or similar to those available in the United States, said co-author Lolkje T.W. de Jong-van den Berg.

Goldberg noted that AHA guidelines issued in July recommend that women not take hormones solely to prevent cardiovascular disease because of recent conflicting research on whether estrogen helps or harms the heart.

Birth control pills are thought to increase the risk of cardiovascular disease in women who smoke or have high blood pressure.

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