Pulmonary function, chronic respiratory symptoms, and health-related quality of life among adults in the United States – National Health and Nutrition Examination Survey 2007–2010

BACKGROUND We examined the association of impaired lung function and respiratory symptoms with measures of health status and health-related quality of life (HRQOL) among US adults. METHODS The sample included 5139 participants aged 40-79 years in the National Health and Nutrition Examination Survey 2007-2010 who underwent spirometric testing and responded to questions about respiratory symptoms, health status, and number of physically unhealthy, mentally unhealthy, or activity limitation days in the prior 30 days. RESULTS Among these adults, 7.2% had restrictive impairment (FEV1/FVC ≥ 70%; FVC < 80% of predicted), 10.9% had mild obstruction (FEV1/FVC < 70%; FEV1 ≥ 80% predicted), and 9.0% had moderate-severe obstruction (FEV1/FVC < 70%; FEV1 < 80% predicted). Individuals with restrictive impairment or moderate-severe obstruction were more likely to report fair/poor health compared to those with normal lung function (prevalence ratio (PR) =1.5 [95% CI: 1.2-1.9] and 1.5 [1.3-1.8]), after controlling for sociodemographics, non-respiratory chronic diseases, body mass index, smoking, and respiratory symptoms. Frequent mental distress (FMD; ≥14 mentally unhealthy days), frequent physical distress (FPD; ≥14 physically unhealthy days), and frequent activity limitation (FAL; ≥14 activity limitation days) did not differ by lung function status. Adults who reported any respiratory symptoms (frequent cough, frequent phlegm, or past year wheeze) were more likely to report fair/poor health (PR = 1.5 [1.3-1.7]), FPD (PR = 1.6 [1.4-1.9]), FMD (PR = 1.8 [1.4-2.2]), and FAL (PR = 1.4 [1.1-1.9]) than those with no symptoms. CONCLUSIONS These results suggest the importance of chronic respiratory symptoms as potential risk factors for poor HRQOL and suggest improved symptom treatment and prevention efforts would likely improve HRQOL.