High cholesterol levels, which have been linked to heart disease, may also lead to kidney damage, a new study suggests. Researchers Tobias Kurth, Elke Schaeffner and colleagues at Bostonâ€™s Brigham and Womenâ€™s Hospital found that men who had low levels of HDL or â€œgood cholesterolâ€ and elevated â€œbadâ€ or LDL cholesterol were twice as likely to have evidence of kidney malfunction.
In the study, researchers looked at blood test records of 4,483 men enrolled in the Physiciansâ€™ Health Study, a large study designed to test methods to prevent cancer and heart disease, from 1982-96.
All were healthy and had normal kidney function at the start of the study. After 14 years, those with high cholesterol were more likely to have signs of kidney damage. â€œWe took a measure that is already indicating a kidney problem which might progress to a more severe kidney disease state,â€ says Kurth, the studyâ€™s project director.
Excess amounts of cholesterol, a fatty substance found in blood, can be deposited in arteries, causing blockages that create the symptoms of heart disease. Similar damage to blood vessels could be responsible for damaging kidneys, the researchers say. It has been known that people with serious kidney disease have high cholesterol, and studies in animals suggest a cause-and-effect relationship, but this is the first study to suggest that even in healthy men, high cholesterol may be damaging kidneys.
â€œThis is another reason to keep (cholesterol levels) in normal ranges,â€ Kurth says. Clogged coronary arteries can be expanded with such methods as angioplasty, to allow blood to flow more freely, he says, but â€œthe problem is that with the kidney, if you have damage thereâ€™s almost no treatment. Thereâ€™s nothing you can do but try to keep it stableâ€ to stop progression of disease.
Studies are under way to determine if people who already suffer from kidney disease can benefit from statins, cholesterol-lowering drugs. Kurth says the new study doesnâ€™t suggest that healthy men should start taking statins, but does mean that keeping cholesterol under control could benefit not only hearts, but kidneys, too.