['We investigated the association between climatic variables and testicular torsion in Taiwanese males.', 'Using the Taiwan Longitudinal Health Insurance Database, we reviewed the files of patients who were diagnosed with testicular torsion and underwent orchiectomy or orchiopexy between January 1996 and December 2008. Children younger than 1 year were excluded from the study. Climatic data were provided by the Taiwan Central Weather Bureau and included ambient temperature, relative humidity, diurnal temperature change and barometric pressure. Patients with acute appendicitis who underwent appendectomy were chosen as the control group. Climatic variables in relation to testicular torsion were analyzed using the Mann-Whitney U test and chi-square test, and seasonal climatic variations using the Kruskal-Wallis H test. Relative risk was calculated to compare the incidence of testicular torsion for diurnal temperature changes.', 'A total of 65 patients with a mean age of 16.2 years presented with testicular torsion and were treated surgically. Four children younger than 1 year were excluded, and thus the study population consisted of 61 patients. The estimated incidence of testicular torsion was 2.58 per 100,000 person-years. There were no special climatic conditions on days of admission. However, 73.7% of the patients had testicular torsion when the diurnal temperature change was 6C or greater. Compared to the torsion rate for diurnal temperature changes less than 6C, the relative risk of testicular torsion at 6C or greater was 1.8 (p = 0.05). Average seasonal diurnal temperature change in the 2 days before hospitalization showed increases in all seasons except spring, which fluctuated.'] Is diurnal temperature change associated with testicular torsion : a nationwide , population based study in Taiwan?