HYPEROXALURIA IN PATIENTS WITH IDIOPATHIC CALCIUM NEPHROLITHIASIS

We studied 476 patients with idiopathic renal calcium stone disease (2 86 M,190 Fl while they ate their customary diets,Each subject collecte d a 24-hour urine sample and completed a dietary diary for a 3-day per iod. Daily urinary oxalate excretion (M 0.24+/-0.15 mg/dl, F 0.23+/-0. 15 mg/dl) and nutrient intake values were calculated and multiple regr ession analyses were performed. Daily urinary oxalate excretion was si gnificantly (p<0.001) related to urinary volume (R=0.24),vitamin C int ake (R=0.33) and body mass index (R=0.37) and inversely related to cal cium intake (R=-0.35). We conclude that urinary oxalate reflects endog enous oxalate production,presumably related to body size,but also inte stinal absorption of oxalate,related to dietary intake and to the effe ct of dietary calcium intake which reduces intestinal oxalate absorpti on.