Association of generic health-related quality of life (EQ-5D dimensions) and inactivity with lung function in lung-healthy German adults: results from the KORA studies F4L and Age.

PURPOSE: Among patients with lung disease, decreased lung function is associated with lower health-related quality of life. However, whether this association is detectable within the physiological variability of respiratory function in lung-healthy populations is unknown. We analyzed the association of each EQ-5D-3L dimension (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) and self-reported physical inactivity with spirometric indices in lung-healthy adults. Modulating effects between inactivity and EQ-5D dimensions were considered. METHODS: 1132 non-smoking, apparently lung-healthy participants (48% male, aged 64 ± 12 years) from the population-based KORA F4L and Age surveys in Southern Germany were analyzed. Associations of each EQ-5D dimension and inactivity with spirometric indices serving as outcomes (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, and mid-expiratory flow) were examined by linear regression, considering possible confounders. Interactions between EQ-5D dimensions (no problems/any problems) and inactivity (four categories of time spent engaging in exercise: inactive to most active) were assessed. RESULTS: Among all participants 42% reported no problems in any EQ-5D dimension, 24% were inactive and 32% exercised > 2 h/week. After adjustment, FEV1 was - 99 ml (95% CI - 166; - 32) and FVC was - 109 ml (95% CI - 195; - 24) lower among subjects with mobility problems. Comparable estimates were observed for usual activities. Inactivity was negatively associated with FVC (ß-coefficient: - 83 ml, 95% CI - 166; 0), but showed no interactions with EQ-5D. CONCLUSIONS: Problems with mobility or usual activities, and inactivity were associated with slightly lower spirometric parameters in lung-healthy adults, suggesting a relationship between perceived physical functioning and volumetric lung function.