Pulmonary function and health-related quality of life among U.S. adults – National Health and Nutrition Examination Survey, 2007-2008

Objective: To examine associations of impaired lung function with measures of health status and health-related quality of life (HRQOL) among U.S. adults. Methods: We used data from participants aged 40-79 years of the National Health and Nutrition Examination Survey 2007-2008 who underwent spirometric testing and responded to questions about health status and number of physically unhealthy, mentally unhealthy, or activity limitation days in the prior 30 days. Results: Among 2492 adults, 8.1% had restrictive impairment (FEV1/FVC ≥ 70% and FVC <80% of predicted), 10.6% had mild obstructive impairment (FEV1/FVC < 70% and FEV1 ≥ 80% predicted), and 10.3% had moderate-severe obstructive impairment (FEV1/FVC < 70% and FEV1 < 80% predicted). After controlling for sociodemographic variables and several chronic diseases, higher percentages of adults with restrictive (25.8%) or moderate-severe obstructive impairment (22.4%) reported having fair to poor health than those with normal lung function (14.1%, both p<0.05). Frequent (≥14) physically unhealthy days were more common among those with moderate-severe obstruction (15.0%) than among those with normal function (10.1%, p<0.05). Frequent (≥14) activity limitation days were more common among those with restrictive impairment (6.5%) compared to those with normal function (3.9%, p<0.05). Frequent (≥14) mentally unhealthy days did not differ by lung function status. Conclusions: Restrictive and moderate-severe obstructive impairment were associated with negative measures of general health and HRQOL among adults from the general population. These results suggest the importance of impaired lung function as a potential risk factor for poor HRQOL.