Nephrolithiasis in elderly population; effect of demographic characteristics

BACKGROUND: Kidney stone (nephrolithiasis) is one of the most common diseases. During the past several decades, its prevalence and incidence have increased markedly in elderly population. OBJECTIVES: This study was conducted to evaluate the risk factors for nephrolithiasis in elderly population. PATIENTS AND METHODS: This study was based on the Amirkola Health and Ageing Project (AHAP). Elderly people with kidney stones in every size, type and number were considered to be the case group and other subjects without a history of kidney stones served as control group. Demographic and anthropometric data, smoking, diabetes and metabolic syndrome (MetS), calcium (Ca), vitamin D, parathyroid hormone (PTH), uric acid and urine pH were compared in both groups. RESULTS: In this study, 1390 elderly people with the mean age of 69.37 ± 7.42 years were evaluated which 202 (14.53%) cases had renal stones. The patients with nephrolithiasis were younger (P = 0.010) and had higher uric acid and body mass index (BMI) levels (P = 0.041 and P = 0.006, respectively). Age <75 years, male gender and BMI ≥30 kg/m(2) had a significant association with stone formation. The prevalence of diabetes, MetS and smoking in the patients with nephrolithiasis was lower than the subjects without it. CONCLUSIONS: This study suggests that male gender, obesity and age <75 years might be independent risk factors for the development of nephrolithiasis. Hence, low animal protein intake and weight reduction should be included as part of the counseling of senior stone-formers.