Interaction of smoking and domestic animal exposure associated with decreased lung function in adults of Southeastern China.

BACKGROUND

Exposure to smoking and domestic animals often occur simultaneously. However, epidemiological evidence on the independent and combined effects of smoking and domestic animal exposure on adult lung function is limited.

OBJECTIVES

The purpose of this study was to explore the interaction of smoking and domestic animal exposure on adult lung function.

METHODS

A total of 6,277 adults were recruited from Southeastern China in this study. Lung function measurements included forced expiratory volume in 1 s (FEV1); forced vital capacity (FVC); FEV1/FVC ratio; peak expiratory flow (PEF); and forced expiratory flow (FEF)25 %, FEF50 %, and FEF75 %. The interaction between smoking and domestic animal exposure was assessed by including a product term in the linear regressions, with the coefficient of the product term (β) used as a measure of interaction. Stratified analysis was conducted for smoking behavior and animal types.

RESULTS

Among smokers, lung function declined more in those with domestic animal exposure than in those without: the βs for FVC, FEV1, FEV1/FVC ratio, and PEF were -0.13 (95 % CI: -0.23, -0.03), -0.15 (-0.23, -0.08), -1.78 (-3.29, -0.27), and -0.43 (-0.67, -0.20), respectively, with them varied with smoking behavior and was greatest on FEV1/FVC ratio. Moreover, we found that only poultry exposure exhibited an interaction with smoking, the βs for FVC; FEV1; FEV1/FVC ratio; PEF; FEF25 %, and FEF50 % were -0.22 (-0.35, -0.08); -0.24 (-0.34, -0.15); -2.93 (-4.86, -1.00); -0.64 (-0.94, -0.35); -0.51 (-0.86, -0.15), and -0.32 (-0.53, -0.11), respectively.

CONCLUSIONS

Poultry exposure exacerbated the adverse effects of smoking on lung function in adults. This study suggests that individuals engaged in poultry-related industries should quit smoking to reduce lung function decline.