Exploring the influence of smoking and alcohol consumption on clinical severity in patients with facioscapulohumeral muscular dystrophy

Despite the growing knowledge on the (epi)genetic background of facioscapulohumeral muscular dystrophy (FSHD), the substantial variability in disease severity that exists between FSHD patients is not fully understood. We hypothesized that smoking and alcohol consumption are disease modifiers in FSHD and contribute to the variability in disease severity, because they are both associated with higher levels of oxidative stress in muscle tissue. Oxidative stress is known to influence FSHD muscle tissue. One hundred and ninety-eight genetically confirmed FSHD patients completed a questionnaire from which the number of packyears of smoking and the lifetime cumulative alcohol units consumed were calculated. Disease severity was determined by the FSDH evaluation score. Multiple linear regression analyses showed that both the number of packyears and the amount of alcohol consumption did not influence disease severity (respectively B = 0.025, ΔR2=0.006, p = 0.231; and B = 0.000, ΔR2=0.004, p = 0.406). Although smoking and excessive alcohol consumption are unhealthy habits which should be discouraged, these results show that smoking and alcohol consumption have no clinically meaningful modifying effect on disease severity in FSHD patients. However, prospective data should show whether alcohol consumption and smoking influence disease progression rate.