Influence of atherosclerosis on age-related changes in renal size and function

Background Renal size and function reflect the health of the kidney. These parameters are associated with age, gender and body weight. The kidneys are also influenced by micro- and macrovascular diseases. Atherosclerotic markers and risk factors may influence the age-related changes of renal size and function. Methods Data of 1056 patients who entered the SMART-study (Second Manifestations of ARTerial disease) were used to assess the effect of atherosclerosis on the relationship between age and renal size and function and to study the effect of atherosclerosis on renal size and function. Patients who were newly referred to the hospital with manifestations of vascular disease were screened for asymptomatic atherosclerosis with noninvasive tests. The carotid intima-media thickness (IMT) and albuminuria were used as estimates for the atherosclerotic burden. Renal size was defined as the mean pole-to-pole length of both kidneys measured by ultrasonography. Renal function was represented by serum creatinine. Results Intima-media thickness was a significant effect modifier of the age-renal size relationship (P = 0·041). The increase of serum creatinine with age was more pronounced in the highest tertile of IMT (P = 0·048). Renal size decreased equally with age in patients with and without hypertension or diabetes mellitus (DM). The same held true for the age-renal function relationship. Albuminuria and DM were independent predictors of renal size and function. Conclusion Atherosclerosis accelerates the decrease of renal size and the increase of serum creatinine with age. Renal size and function are determined by albuminuria and DM.