During the past year we have completed extensive analyses of the data from both the child and adult components of the NHANES surveys. We have examined a U-shaped association between sleep duration and cardiovascular diseases (CVD). We included an adult sample of the 2005 to 2008 NHANES surveys and divided respondents into 3 groups according to their usual sleep duration on weekdays, namely <6 hours (14.1%), 6-8 hours (78.8%), and 9 hours (7.0%). We found U-shaped associations of sleep duration with the risk quintiles of CVD biomarkers (including systolic blood pressure (SBP), C-reactive Protein (CRP), and urinary albumin-to-creatinine ratio) and with CVD (congestive heart failure (CHF), heart attack, stroke and any CVD) in univariate analyses. However, with the exception of CRP, most of the associations between long sleep duration and CVD and biomarkers dissipated after controlling for demographic and clinical factors. By contrast, the majority of significant associations found in short sleep duration persisted in the fully adjusted models, except for CRP and CHF. Subgroup analyses revealed that the associations between short sleep duration and the high risk quintile of SBP, stroke and any CVD occurred in females only. These results demonstrate that there are different mechanisms for the associations of short and long sleep duration with CVD and biomarkers. The association of CVD with long sleep duration is attributable to comorbid non-CVD conditions, whereas there is a direct association between most CVD outcomes and short sleep duration after adjusting for non-CVD conditions and CVD biomarkers, particularly in females. (Zhang et al., under review). We also have investigated a potential association between biologically-confirmed secondhand smoke exposure (serum cotinine) and symptoms of DSM-IV disorders in 8-15 year-old youth using NHANES 2001-2004 survey data. We found among non-smokers, serum cotinine was positively associated with symptoms of DSM-IV major depressive disorder, generalized anxiety disorder, attention-deficit/hyperactive disorder, and conduct disorder, after adjustment for survey design, age, gender, race/ethnicity, poverty, migraine, asthma, hay fever, whether mother smoked during pregnancy, and allostatic load. The association with serum cotinine was more apparent for non-Hispanic Whites and males. Our study findings are consistent with a growing body of research documenting associations between secondhand smoke exposure and mental health outcomes. Future research is warranted to establish the biological and/or psychological mechanisms of association. (Bandiera et al., 2011) Public Health Impact: These findings provided evidence from the general population that broaden our knowledge and provide new information on the association between sleep duration and cardiovascular disorders and biomarkers in U.S. adults and negative effects of secondhand smoking on youth psychiatric disorders. These results are a significant step towards research to understand biologic mechanisms, identify more homogeneous subgroups in clinical and genetic studies, and develop better clinical management. Future Plans Future analyses will examine the risk factors and sociodemographic and biological correlates of conduct disorder and investigate the association between headache and psychiatric comorbidity in the general population. We will prioritize our analyses to address the key study questions that are the focus of our own research.
