Seasonal Variations in Urinary Excretion of Calcium and Oxalate in Normal Subjects in Patients with Idiopathic Hypercalciuria

A longitudinal 9-year retrospective study of 24-hour urinary calcium values has been made in a metabolic stone clinic amongst patients with idiopathic hypercalciuria. No seasonal variations could be observed in contrast ot a previous study from Leeds, A prospective longitudinal study was made of 24-hour urinary calcium values in a small group of normal subjects. No seasonal variation could be ovserved. In the prospective study no seasonal variations in urinary oxalate could be observed. In a 2-year longitudinal study of stone patients with idiopathic hypercalciuria, urinary oxalate was found to be higher in the summer than in the winter. This was attributed to the combination of a higher intake of oxalate-rich foods in the summer, and the low calcium diet with which they were treated.