Bui DS, et al. - Researchers investigated the lung function trajectories over the lifespan. They also determined their determinants, and outcomes from the first to the sixth decade of life. Out of the six potential FEV₁ trajectories identified in this study, two were novel. The contribution of 3 trajectories to 75% of chronic obstructive pulmonary disease (COPD) burden as well as their relation to modifiable early-life exposures was reported, whose impact was aggravated by adult factors. To minimise COPD risk, reducing maternal smoking, encouraging immunisation, and avoiding personal smoking, especially in those with smoking parents or low childhood lung function was recommended. With respect to the potential long-term implications of non-optimal asthma control for lung function trajectory throughout life, awareness in clinicians and patients with asthma appeared important.

Methods

• Using six waves of the Tasmanian Longitudinal Health Study (TAHS), researchers modeled lung function trajectories measured at 7, 13, 18, 45, 50, and 53 years.
• They used group-based trajectory modelling to analyse pre-bronchodilator FEV1 z-scores at the six timepoints, to ultimately identify distinct subgroups of individuals whose measurements followed a similar pattern over time.
• They used logistic regression to relate the trajectories identified to childhood factors and risk of chronic obstructive pulmonary disease (COPD), and population-attributable fractions of COPD were also estimated.

Results

• The original cohort comprised 8583 participants, of whom 2438 comprised the study population and had at least two waves of lung function data at age 7 years and 53 years.
• Six trajectories identified by the researchers are as follows: early below average, accelerated decline (97 [4%] participants); persistently low (136 [6%] participants); early low, accelerated growth, normal decline (196 [8%] participants); persistently high (293 [12%] participants); below average (772 [32%] participants); and average (944 [39%] participants).
• They found increased risk of COPD at age 53 years across the three trajectories ie, early below average, accelerated decline; persistently low; and below average compared with the average group (early below average, accelerated decline: odds ratio 35·0, 95% CI 19·5–64·0; persistently low: 9·5, 4·5–20·6; and below average: 3·7, 1·9–6·9).
• Childhood asthma, bronchitis, pneumonia, allergic rhinitis, eczema, parental asthma, and maternal smoking were identified as early-life predictors of the three trajectories.
• Findings revealed personal smoking and active adult asthma increased the influence of maternal smoking and childhood asthma, respectively, on the early below average, accelerated decline trajectory.