Urinary Albumin Excretion Predicts Future Cardiovascular Disease, Hypertension, and Kidney Disease

Higher urinary albumin excretion predicts future cardiovascular disease, hypertension, and chronic kidney disease. Physical activity improves endothelial function so activity may reduce albuminuria. Among diabetics, physical activity decreases albuminuria. In nondiabetics, prior studies have shown no association. The authors explored the cross-sectional association between physical activity and albuminuria in 3,587 nondiabetic women in 2 US cohorts, the Nurses' Health Study I in 2000 and the Nurses' Health Study II in 1997. Physical activity was expressed as metabolic equivalents per week. The outcome was the top albumin/creatinine ratio (ACR) decile. Secondary analyses explored the ACR association with strenuous activity and walking. The mean age was 58.6 years. Compared with women in the lowest physical activity quintile, those in the highest quintile had a multivariate-adjusted odds ratio for the top ACR decile of 0.65. The multivariate-adjusted odds ratio for the top ACR decile for those with greater than 210 minutes per week of strenuous activity compared with no strenuous activity was 0.61, and for those in the highest quintile of walking compared with the lowest quintile, it was 0.69. Greater physical activity is associated with a lower ACR in nondiabetic women.

Albuminuria at levels as low as 5 mg/g of creatinine is predictive of incident hypertension, major cardiovascular events, and all-cause mortality, even in patients without a baseline history of cardiovascular disease. It is unlikely that albuminuria directly causes the vascular disease. Instead, although the pathophysiology is not completely elucidated, it seems that albuminuria is an early marker of generalized endothelial dysfunction and permeability. If this is the case, any intervention that prevents albuminuria may also confer protection on the endothelium and prevent progression from early endothelial dysfunction to clinical manifestations of cardiovascular disease.

Although the mean age of our population was 58.6 years, modifying risk factors for future development of hypertension is still paramount. The Systolic Hypertension in the Elderly Program known as the "SHEP Trial" demonstrated that, in individuals over the age of 60 years, treatment of systolic hypertension reduced both stroke and major cardiovascular events, and baseline hypertension was predictive of a more rapid decline in renal function.The Hypertension in the Very Elderly Trial known as the "HYVET Trial" then demonstrated that even individuals with a mean age of 83.6 years had a benefit from antihypertensive treatment in preventing stroke, heart failure, and overall mortality. Therefore, prevention of albuminuria in this age group could be important in preventing the development of hypertension and subsequent major cardiovascular events.

In conclusion, higher levels of physical activity are associated with lower urinary albumin excretion in nondiabetic women. Physical activity may be beneficial in reducing albuminuria.

Gerstein HC, Mann JF, Yi Q, et al. Albuminuria and risk of cardiovascular events, death, and heart failure in diabetic and nondiabetic individuals. JAMA. 2001;286(4):421–426

Eshøj O, Feldt-Rasmussen B, Larsen ML, et al. Comparison of overnight, morning and 24-hour urine collections in the assessment of diabetic microalbuminuria. Diabet Med. 1987;4(6):531–533.