EFFECT OF HYPERTENSION, DIABETES AND OTHER CARDIOVASCULAR RISK-FACTORS ON KIDNEY SIZE IN MIDDLE-AGED ADULTS

The aim of the study was to investigate in a population-based series ( 1031 subjects, age range 40-60 years) whether the renal size of hypert ensive subjects differs from that of control subjects and whether the difference might be due to hypertension itself or risk factors associa ted with hypertension. The renal measurements were performed by abdomi nal ultrasound. The genders were analyzed separately. Hypertensive men had slightly larger kidneys than controls (70.1 +/- 8.9 cm(2) vs. 67. 9 +/- 8.7 cm(2), p < 0.008). The difference was, however, mediated mai nly through the body mass index (BMI), whereas hypertension, blood pre ssure or hypertensive medication did not affect renal size. High serum concentrations of uric acid and creatinine were associated with small er kidney size (p < 0.001 and p < 0.05, respectively). Alcohol users h ad slightly larger kidneys than abstainers, but the difference was not significant. Renal size increased with pack years of smoking. Diabeti cs had 4.8% larger kidneys (p < 0.039), but no difference was observed between the subjects with impaired glucose tolerance and those with n ormal test results. In multivariate analysis, the most significant fac tors associated with enlarged kidney size were the fasting blood gluco se concentration (p less than or equal to 0.0001), smoking (p less tha n or equal to 0.0001) and atherosclerotic lesions in carotid arteries (p < 0.002). The kidneys were also slightly larger in hypertensive wom en than in control subjects, but the difference was only of borderline significance (p < 0.08). Women on hormone replacement therapy had sma ller kidneys than other women (p < 0.05), but there was no difference in renal measures between premenopausal and postmenopausal women. In m ultivariate analysis, the most significant factors contributing to lar ge kidney size were blood glucose concentration ip < 0.0001) and smoki ng (p < 0.05), while age and serum creatinine concentration were assoc iated with smaller kidney size (p < 0.0001 and p < 0.0001). We conclud e that renal size is related to sex and the subject's height and weigh t. Smoking, abnormal glucose tolerance, blood uric acid, creatinine, c arotid atherosclerosis and hormone replacement therapy in women were a lso significant factors for renal size. Hypertensive subjects had larg er kidneys than controls, mainly because of their more frequent obesit y and abnormal glucose test.