Association of environmental tobacco smoke at work and forced expiratory lung function among never smoking asthmatics and non-asthmatics

Inconsistencies across studies on the association of environmental tobacco smoke (ETS) and pulmonary function maybe clarified addressing potentially s usceptible subgroups. We determined the association of ETS exposure at work with FVC, FEV1, and FEF25-75% in life-time never smokers (N = 3534) of the SAPALDIA random population sample (age 18-60). We considered sex, bronchia l reactivity, and asthma status as a priori indicators to identify suscepti ble riskgroups. The multivariate regression models adjusted for height, age , education, dust/aerosol exposure, region, and ETS at home. Overall, ETS w as not significantly associated with FVC (0.7%; -0.4 to +1.8), FEV1 (-0.1%; 95% CI:-1.3 to + 1.1) or FEF25-75% (-1.9%; -4.2 to +0.5). Effects were obs erved among asthmatics (n = 325), FEV1 (-4.8%; 0 to -9.2); FEF25-75% (-12.4 %; -3.7 to -20.4); FVC: (-1.7% +2.1 to -5.5), particularly in asthmatic wom en (n = 183). FVC -4.4% (-9.6 to + 1.1); FEV1: -8.7% (-14.5 to -2.5); FEF25 -75 %: -20.8% (-32 to -7.6), where duration of ETS exposure at work was ass ociated with lung function (FFV1 -6% per hour of ETS exposure at work (p = 0.01); FEF25-75%: -3.4%/h (p < 0.05). in non-asthmatic women (n = 1963) and in men no significant effect was observed. The size of the observed effect among susceptible subgroups has to be considered clinically relevant. Howe ver; due to inherent limitations of this cross-sectional analysis, selectio n or information biases may not be fully controlled. For example, asthmatic women reported higher ETS exposure at work than asthmatic men. Given the p ublic health importance to identify susceptible subgroups, these results ou ght to be replicated.