Seasonal variations in the incidence of ureteric colic.

A retrospective study of 1097 male in-patients with ureteric colic was conducted to try and define the aetiological effect of climate on the disease. The overall monthly incidence for the study period of 10 years was found, on statistical analysis to correlate with ambient temperature thus: (1) directly with the mean temperature of the preceding month, (2) directly with the difference between mean maximum and mean minimum temperatures of the same month, and (3) inversely with the mean maximum temperature of the same month. The correlation was interpreted on the basis that hot ambient temperatures promoted stone generation whereas cold ones promoted stone descent through cold-induced diuresis. This trend, among its other implications, could pinpoint the reason for the increase in nephrolithiasis with industralisation.