Doctor-diagnosed sleep disorders in the United States: Prevalence and impact of tobacco smoke exposure and vitamin D deficiency. A population-based study.

Background and purpose: We determined the prevalence of physician-diagnosed sleep disorder and its association with tobacco smoke exposure and vitamin D deficiency. Methods: The National Health and Nutrition Examination Survey (NHANES) of 2011-2012 data base was used for the study. Subjects were asked two questions: "Ever told your doctor you had trouble sleeping?" and "Ever told by doctor have sleep disorder?" The answer "yes" to the second question indicated presence of a doctor-diagnosed sleep disorder (DSD) and "no" indicated its absence. Tobacco smoke exposure was defined by serum cotinine levels while vitamin D levels were measured by serum 25(OH) D. Eight selected variables included in the analyses were BMI, age, gender, smoking exposure, vitamin D levels, income, insurance, and race. Univariate and multivariate analyses were conducted to determine if tobacco smoke exposure and Vitamin D were each predictive of DSD. Results: Of 5,470 subjected aged 16 to 80+ years about 9% had doctor-diagnosed sleep disorder (DSD). In a multiple regression analysis, active tobacco smoking was predictive of DSD (OR 1.92; 95% CI = 1.38-2.69), while passive smoke exposure was not, even after controlling for all the other significant variables (OR 0.93; 95% CI = 0.57-1.52). The other variables significantly associated with DSD were by order of importance BMI ( Conclusion: The prevalence of physician-diagnosed DSD was about 9%. Active smoking but not passive smoking as defined by cotinine levels was significantly associated with DSD. Vitamin D was not predictive of DSD. Future studies are therefore needed to demonstrate whether smoking cessation could help reduce DSD.