Lifetime lung function is related to quality of life and longevity. Over the lifespan, individuals follow different lung function trajectories. Identification of these trajectories, their determinants, and outcomes is important, but no study has done this beyond the fourth decade. We used six waves of the Tasmanian Longitudinal Health Study (TAHS) to model lung function trajectories measured at 7, 13, 18, 45, 50, and 53 years. We analysed pre-bronchodilator FEV1 z-scores at the six timepoints using group-based trajectory modelling to identify distinct subgroups of individuals whose measurements followed a similar pattern over time. We related the trajectories identified to childhood factors and risk of chronic obstructive pulmonary disease (COPD) using logistic regression, and estimated population-attributable fractions of COPD. Of the 8583 participants in the original cohort, 2438 had at least two waves of lung function data at age 7 years and 53 years and comprised the study population. We identified six trajectories: 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). The three trajectories early below average, accelerated decline; persistently low; and below average had increased risk of COPD at age 53 years 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). Early-life predictors of the three trajectories included childhood asthma, bronchitis, pneumonia, allergic rhinitis, eczema, parental asthma, and maternal smoking. Personal smoking and active adult asthma increased the impact of maternal smoking and childhood asthma, respectively, on the early below average, accelerated decline trajectory. We identified six potential FEV1 trajectories, two of which were novel. Three trajectories contributed 75% of COPD burden and were associated with modifiable early-life exposures whose impact was aggravated by adult factors. We postulate that reducing maternal smoking, encouraging immunisation, and avoiding personal smoking, especially in those with smoking parents or low childhood lung function, might minimise COPD risk. Clinicians and patients with asthma should be made aware of the potential long-term implications of non-optimal asthma control for lung function trajectory throughout life, and the role and benefit of optimal asthma control on improving lung function should be investigated in future intervention trials. National Health and Medical Research Council of Australia; European Union's Horizon 2020; The University of Melbourne; Clifford Craig Medical Research Trust of Tasmania; The Victorian, Queensland & Tasmanian Asthma Foundations; The Royal Hobart Hospital; Helen MacPherson Smith Trust; and GlaxoSmithKline.

Rationale: The burden of chronic obstructive pulmonary disease (COPD) is increasing, yet there are limited data on early life risk factors. Objectives: To investigate the role of childhood lung function in adult COPD phenotypes. Methods: Prebronchodilator spirometry was performed for a cohort of 7-year-old Tasmanian children (n = 8,583) in 1968 who were resurveyed at 45 years, and a selected subsample (n = 1,389) underwent prebronchodilator and post-bronchodilator spirometry. For this analysis, COPD was spirometrically defined as a post-bronchodilator FEV₁/FVC less than the lower limit of normal. Asthma–COPD overlap syndrome (ACOS) was defined as the coexistence of both COPD and current asthma. Associations between childhood lung function and asthma/COPD/ACOS were examined using multinomial regression. Measurements and Main Results: At 45 years, 959 participants had neither current asthma nor COPD (unaffected), 269 had current asthma alone, 59 had COPD alone, and 68 had ACOS. The reweighted prevalence of asthma alone was 13.5%, COPD alone 4.1%, and ACOS 2.9%. The lowest quartile of FEV₁ at 7 years was associated with ACOS (odds ratio, 2.93; 95% confidence interval, 1.32–6.52), but not COPD or asthma alone. The lowest quartile of FEV₁/FVC ratio at 7 years was associated with ACOS (odds ratio, 16.3; 95% confidence interval, 4.7–55.9) and COPD (odds ratio, 5.76; 95% confidence interval, 1.9–17.4), but not asthma alone. Conclusions: Being in the lowest quartile for lung function at age 7 may have long-term consequences for the development of COPD and ACOS by middle age. Screening of lung function in school age children may identify a high-risk group that could be targeted for intervention. Further research is needed to understand possible modifiers of these associations and develop interventions for children with impaired lung function.

Rationale: Childhood risk factors for long-term lung health often coexist and their specific patterns may affect subsequent lung function differently. Objectives: To identify childhood risk factor profiles and their influence on lung function and chronic obstructive pulmonary disease (COPD) in middle age, and potential pathways. Methods: Profiles of 11 childhood respiratory risk factors, documented at age 7, were identified in 8,352 participants from the Tasmanian Longitudinal Health Study using latent class analysis. We investigated associations between risk profiles and post-bronchodilator lung function and COPD at age 53, mediation by childhood lung function and adult asthma, and interaction with personal smoking. Results: Six risk profiles were identified: 1) unexposed or least exposed (49%); 2) parental smoking (21.5%); 3) allergy (10%); 4) frequent asthma, bronchitis (8.7%); 5) infrequent asthma, bronchitis (8.3%); and 6) frequent asthma, bronchitis, allergy (2.6%). Profile 6 was most strongly associated with lower forced expiratory volume in 1 second (FEV1) (−261; 95% confidence interval, −373 to −148 ml); lower FEV1/forced vital capacity (FVC) (−3.4; −4.8 to −1.9%) and increased COPD risk (odds ratio, 4.9; 2.1 to 11.0) at age 53. The effect of profile 6 on COPD was largely mediated by adult active asthma (62.5%) and reduced childhood lung function (26.5%). Profiles 2 and 4 had smaller adverse effects than profile 6. Notably, the effects of profiles 2 and 6 were synergistically stronger for smokers. Conclusions: Profiles of childhood respiratory risk factors predict middle-age lung function levels and COPD risk. Specifically, children with frequent asthma attacks and allergies, especially if they also become adult smokers, are the most vulnerable group. Targeting active asthma in adulthood (i.e., a dominant mediator) and smoking (i.e., an effect modifier) may block causal pathways and lessen the effect of such established early-life exposures.