Bisphenol-A and Sleep Adequacy among Adults in the National Health and Nutrition Examination Surveys

Study Objectives: To evaluate bisphenol-A (BPA) level and its relationship to sleep adequacy in a nationally representative sample of U.S. adults. Methods: A population-based cross-sectional study was conducted using 2005-2010 National Health and Nutrition Examination Survey whereby data were collected using in-person interviews, physical examination and laboratory testing. BPA level was measured in urine samples and analyzed as loge-transformed variable and in quartiles (< 0.9 ng/mL; 0.9 to < 1.9 ng/mL; 1.9 to < 3.7 ng/mL; 3.7+ ng/mL). Sleep adequacy was operationalized with three questions: How much sleep do you usually get at night on weekdays or workdays?, Have you ever told a doctor or other health professionals that you have trouble sleeping? and Have you ever been told by a doctor or other health professional that you have a sleep disorder? Sleep duration was further categorized as (< 6 h, >= 6 h); (< 7 h, 7-8 h, > 8 h); (< 5 h, 5-6 h, 7-8 h, >= 9 h). Linear, binary, and ordinal logistic regression models were constructed. Results: Loge-transformed BPA level was inversely related to sleep duration defined, in hours, as a continuous variable, a dichotomous variable (>= 6, < 6), or an ordinal variable (>= 9, 7-8, 5-6, < 5), after adjustment for confounders. Help-seeking behavior for sleep problems and diagnosis with sleep disorders were not significantly associated with loge-transformed BPA level in fully adjusted models. Conclusions: Loge-transformed BPA level may be associated with fewer hours of sleep among U.S. adults, with implications for prevention. Further research involving diverse populations are needed to confirm these study findings.