Cold weather increases the risk of scrotal torsion events: results of an ecological study of acute scrotal pain in Scotland over 25 years.

The role of ambient temperature in the aetiology of acute scrotal pain (ASP) remains uncertain. The most common causes of ASP are torsion of the testis (TT) or its appendages (TA) and epidymo-orchitis (EO). We undertook an ecological study of ASP in Scotland to determine whether a seasonal variation could be observed. Episode reports for TT, TA and EO in Scotland over 25 years were collated monthly. Statistical analyses were performed to determine whether changes in ambient temperature during the year could explain variations in monthly frequency. 7882 episodes of TT and TA (Group A), and 25,973 episodes of EO (Group B) were reported. There was significant variance in the frequency of Group A (p < 0.0001) and B (p = 0.0031) episodes by month, higher frequency of Group A episodes in the colder half of the year (p < 0.0001), and an inverse correlation between the frequency of Group A episodes and ambient temperature (Spearman r = - 0.8757, 95% CI - 0.9661 to - 0.5941, p = 0.0004). Ambient temperature is likely to be playing a role in the aetiology of TT and TA in Scotland but not EO. Further study is warranted to explain underlying mechanisms.