This analysis was undertaken to assess if wood burning exposure was related to pulmonary function; the paper has been published in Environmental Health Perspectives. You can scroll through the executed code at https://juliedwhite.github.io/Woodsmoke_PFTs/
White, J.D., Wyss, A.B., Hoang, T.T., Lee, M.K., Richards, M., Parks, C.G., Beane-Freeman, L.E., Hankinson, J.L., Umbach, D.M., London, S.J. (2022). Residential wood burning and pulmonary function in the Agricultural Lung Health Study. Environmental Health Perspectives. 130(8). https://doi.org/10.1289/EHP10734.
Background
In low- and middle-income countries, burning biomass indoors for cooking or
heating has been associated with poorer lung function. In high-income countries,
wood, a form of biomass, is commonly used for heating in rural areas, with
increasing prevalence. However, in these settings the potential impact of chronic
indoor woodsmoke exposure on pulmonary function is little studied.
Objective
We evaluated the association of residential wood burning with pulmonary function
in a case-control study of asthma nested within a US rural cohort.
Methods
Using sample weighted multivariable linear regression, we estimated associations
between some and frequent wood burning, both relative to no exposure, in
relation to forced expiratory volume in one second (FEV1), forced
vital capacity (FVC), their ratio (FEV1/FVC), and fractional exhaled
nitric oxide (FeNO). We examined effect modification by smoking or asthma status.
Results
Among all participants and within smoking groups, wood burning was not appreciably
related to pulmonary function. However, in asthmatic individuals (n = 1,083),
frequent wood burning was significantly associated with lower FEV1
(β: -164 ml; 95% CI: -261, -66 ml), FVC (β: -125 ml; 95% CI: -230, -20 ml),
and FEV1/FVC (β: -2%; 95% CI: -4, -0.4%), whereas no appreciable
association was seen in individuals without asthma (n = 1,732). These
differences in association by asthma were statistically significant for
FEV1 and FEV1/FVC (Pinteraction FEV1 = 0.0044;
interaction FEV1/FVC = 0.049). Frequent wood burning was also
associated with higher FeNO levels in all individuals (n = 2,598; β: 0.1 ln(ppb);
95% CI: 0.02, 0.2 ln(ppb)), but associations did not differ by asthma or smoking
status.
Discussion
Frequent exposure to residential wood burning was associated with a measure of
airway inflammation (FeNO) among all individuals, and with lower pulmonary
function among asthmatic individuals. This group may wish to reduce wood burning
or consider using air filtration devices.