Prevalence and factors associated with hidradenitis suppurativa: results from two case-control studies.
Conflicting opinions have been reported regarding the epidemiology of hidradenitis suppurativa. We sought to evaluate the prevalence of hidradenitis suppurativa and to identify associated factors. Prevalence was evaluated using a representative sample of the French population (n=10,000). Associated risk factors were assessed using two case-control studies, one population-based with 67 self-reported patients and 200 control subjects, and the other clinic-based with 302 medically assessed patients and 906 control subjects. The prevalence was 1% of the French population. Multivariate analyses showed a strong association with current smoking in self-reported (odds ratio=4.16, 95% confidence interval [2.99-8.69]) and in medically assessed (odds ratio=12.55 [8.58-18.38]) populations. Association with body mass index was significant in medically assessed patients (odds ratio=1.12 [1.08-1.15]) for each increase of 1 U of BMI. A causal relationship could not be established with such a cross-sectional study. Hidradenitis suppurativa is a common disease, frequently associated with smoking and being overweight.