Vitamin D status may predict early kidney disease, according to a study published in the July issue of American Journal of Kidney Disease.
More than 10% of people in the US aged 20 years or older have kidney disease. Additionally, more than 20% of adults with high blood pressure have kidney disease, according to the center for disease control and prevention.
Researchers found that study participants who were deficient in vitamin D were more than twice as likely to have protein in the urine, also called albuminuria, over a period of five years. Albuminuria is an early sign of kidney damage. Its presence in the urine suggests that kidneys are damaged because the kidneys should retain protein for use in the body. Two positive tests for albuminuria over a few weeks are an indication of early kidney disease.
The study included 5,800 men and women who initially had no protein in the urine. Over the five-year follow up, 3.8% developed albuminuria. The vitamin D deficient (<15 ng/ml) participants were 84% more likely to have albuminuria than those with sufficient vitamin D levels. After adjusting for age and other lifestyle factors, those with low vitamin D levels had a 70% increase in albuminuria.
Thomas Manley, director of Scientific Activities for the National Kidney Foundation explains that multiple studies have established a relationship between vitamin D status and kidney disease. “This study supports that relationship and shows that a low vitamin D level increases the likelihood of developing protein in the urine, even among a general population,” he explains.
The study’s lead researcher, Matthew Damasiewicz, MD, concludes that there is mounting evidence on the benefits of correcting vitamin D deficiency to prevent albuminuria. “It is also likely that patients with chronic conditions such as [chronic kidney disease] CKD may need higher vitamin D levels than the general healthy population.”