Lifetime Risk Factors for Pre- and Post-Bronchodilator Lung Function Decline: A Population-based Study

RATIONALE: Interactions between early life and adult insults on lung function decline are not well understood, with most studies investigating pre-bronchodilator (BD) FEV1 decline. OBJECTIVE: To investigate relationships between adult risk factors and pre- and post-BD lung function decline and their potential effect modification by early life and genetic factors. METHODS: Multiple regression was used to examine associations between adult exposures (asthma, smoking, occupational exposures, traffic pollution and obesity) and decline in both pre- and post-BD spirometry (FEV1, FVC and FEV1/FVC) between ages 45 to 53 years in the Tasmanian Longitudinal Health Study (n=857). Effect modification of these relationships by childhood respiratory risk factors including low childhood lung function, and glutathione S-transferase (GST) gene polymorphisms was investigated. RESULTS: Baseline asthma, smoking, occupational exposure to vapours/gases/dusts/fumes (VGDF) and living close to traffic were associated with accelerated decline in both pre- and post-BD FEV1. These factors were also associated with FEV1/FVC decline. Occupational exposure to aromatic solvents was associated with pre-BD but not post-BD FEV1 decline. Maternal smoking accentuated the effect of personal smoking on pre- and post-BD FEV1 decline. Lower childhood lung function and having the GSTM1 null allele accentuated the effect of occupational exposure to VGDF and personal smoking on post-BD FEV1 decline. Incident obesity was associated with accelerated decline in FEV1 and more pronounced in FVC. CONCLUSION: This study provides new evidence for accentuation of individual susceptibility to adult risk factors by low childhood lung function, GSTM1 genotype and maternal smoking.