Smoking, asthma, occupational exposure, and living close to major roads may accelerate postbronchodilator airflow obstruction in middle-aged adults with a history of low childhood lung function and maternal smoke exposure, study results published in the Annals of the American Thoracic Society suggest.

Researchers evaluated the association between adult environmental and health exposures and decline in pre and postbronchodilator spirometry values (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and FEV1/FVC ratio) in patients aged 45 to 53 years who were enrolled in the Tasmanian Longitudinal Health Study. Environmental and health exposures in the analysis included asthma, smoking, occupational exposures, traffic pollution, and obesity. Childhood respiratory risk factors, including low childhood lung function and glutathione S-transferase (GST) gene polymorphisms, were investigated in terms of their relationship to adult exposures.

A total of 857 patients had lung function measured at age 45 and 53 years. At baseline, the prevalence of current asthma was 22.6%, which decreased to 17.5% at age 53 years. Accelerated decline in postbronchodilator FEV1 (mL/y) was associated with baseline asthma (P <.05), baseline smoking (P <.001), baseline occupational exposure to vapors/gases/dusts/fumes (P <.05), and living close to traffic (P <.05). The same adulthood factors at baseline also correlated with decline in FEV1/FVC (%/y).

Between the 2 time points, increasing body mass index was also associated with an accelerated decline in postbronchodilator FEV1 and FVC (excess rates: 3.7 and 5.3 mL/y per kg/m2 increase). Personal smoking among patients in the lowest quartile for childhood lung function had the greatest effect on the accelerated decline in FEV1. Maternal smoking also accentuated the effect of adulthood exposures on airflow obstruction. In addition, patients with the GSTM1 null allele had a demonstrably greater effect of occupational exposure to vapors/gases/dusts/fumes and personal smoking on postbronchodilator airway decline.

The enrichment of the sample at baseline among individuals with asthma and cough may have affected the generalizability of the findings.

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The researchers emphasized “the importance of smoking abstinence and occupational risk for individuals with preexisting low lung function from childhood risk factors and GSTM1 null genotype to minimize harm from accelerated lung function decline in mid-adult life.”

Disclosure: This clinical trial was partially supported by GlaxoSmithKline. Please see the original reference for a full list of authors’ disclosures.

Reference

Bui DS, Perret JL, Walters EH, et al. Lifetime risk factors for pre- and post-bronchodilator lung function decline: a population-based study [published online December 4, 2019]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201904-329OC