Ladies, Urinary Tract Infections Are Seasonal
In many ways, women got the raw end of the biological deal. Not only must they wrestle with the discomfort of pregnancy and the pain of childbirth, they are also far likelier than men to contract and die of breast cancer. Sure, only men get prostate cancer, but more women die from breast cancer alone than men die of prostate and breast cancer combined.
Another unpleasantry? Urinary tract infections (UTIs). Women are likelier to get these too because they have shorter urethras than men, meaning bacteria like E. coli don't have to travel very far to reach the bladder. Sexual activity, birth control and completing menopause are all risk factors for UTIs.
One thing that isn't well understood about UTIs is seasonality. Influenza, for instance, is a seasonal infection; in the northern hemisphere, "flu season" is generally considered to be December to March, with February being the worst month. Is there a "UTI season" as well? A team of French researchers set about answering this question.
Good information on the seasonality of UTIs is difficult to find because epidemiological data isn't reliably collected. So, the authors used two proxies: Sales of antibiotics commonly used to treat UTIs in France and Google searches for "urinary tract infection" (or its language equivalent) in seven different countries. (See graphs.)
The results show a very clear seasonal pattern: UTIs are more common in the summer. (In Brazil and Australia, summer corresponded to winter in the northern hemisphere.)
Why this occurs is unknown, but it makes sense that ambient temperature might be a risk factor for UTI. Also, changes in urination or sexual activity during the summer might explain the results. But, the fact that seasonality is now suspected should give researchers some clues about how to carry on subsequent investigations.
Source: Rossignol L, Pelat C, Lambert B, Flahault A, Chartier-Kastler E, et al. (2013) A Method to Assess Seasonality of Urinary Tract Infections Based on Medication Sales and Google Trends. PLoS ONE 8(10): e76020. doi:10.1371/journal.pone.0076020