Bell’s palsy and obesity, alcohol consumption and smoking: A nested case-control study using a national health screening cohort

The aim of this study was to investigate the association of body mass index (BMI), alcohol consumption, and smoking status with the occurrence of Bell’s palsy. The Korean National Health Insurance Service-Health Screening Cohort of a ≥ 40-year-old population from 2000–2003 was used. A total of 5,632 Bell’s palsy participants were matched with 22,528 control participants in terms of age, sex, income, region of residence, and past medical histories of hypertension, diabetes, and dyslipidemia. Bell’s palsy was classified by a history of ≥2 diagnoses with ICD-10 code (G510) and steroid treatment. BMI (kg/m(2)) was classified as <18.5 (underweight), ≥18.5 to <23 (normal), ≥23 to <25 (overweight), ≥25 to <30 (obese I), and ≥30 (obese II). Alcohol consumption was divided into non-drinkers and those who drank 2–3 times a month, 1–2 times a week, and ≥3 times a week. Smoking status was categorized as current smokers, past smokers, and non-smokers. The odds of obesity, alcohol consumption, and smoking with Bell’s palsy were analyzed using logistic regression analysis. BMI showed proportionally positive associations with Bell’s palsy (adjusted OR [95% CI] = 0.61 [0.47–0.79] for underweight, 1.16 [1.08–1.26] for normal, 1.24 [1.15–1.33] for obese I, and 1.61 [1.38–1.88] for obese II, P < 0.001). The odds of alcohol consumption with Bell’s palsy were 0.90 (95% confidence interval [CI] = 0.82–0.99) for 2–3 times a month, 0.77 (95% CI = 0.69–0.85) for 1–2 times a week, and 0.79 (95% CI = 0.71–0.88) for ≥3 times a week compared to nondrinkers (P < 0.001). Smoking did not show a relationship with the occurrence of Bell’s palsy. Obesity was related to the risk of Bell’s palsy in the population over 40 years old. On the other hand, alcohol consumption was negatively associated with the occurrence of Bell’s palsy.