Objective To conduct a systematic review investigating the normal age-related changes in lung function in adults without known lung disease.
Design Systematic review.
Data sources MEDLINE, Embase and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched for eligible studies from inception to February 12, 2019, supplemented by manual searches of reference lists and clinical trial registries.
Eligibility criteria We planned to include prospective cohort studies and randomised controlled trials (control arms) that measured changes in lung function over time in asymptomatic adults without known respiratory disease.
Data extraction and synthesis Two authors independently determined the eligibility of studies, extracted data and assessed the risk of bias of included studies using the modified Newcastle–Ottawa Scale.
Results From 4385 records screened, we identified 16 cohort studies with 31 099 participants. All included studies demonstrated decline in lung function—forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) with age. In studies with longer follow-up (>10 years), rates of FEV1 decline ranged from 17.7 to 46.4 mL/year (median 22.4 mL/year). Overall, men had faster absolute rates of decline (median 43.5 mL/year) compared with women (median 30.5 mL/year). Differences in relative FEV1 change, however, were not observed between men and women. FEV1/FVC change was reported in only one study, declining by 0.29% per year. An age-specific analysis suggested the rate of FEV1 function decline may accelerate with each decade of age.
Conclusions Lung function—FEV1, FVC and PEFR—decline with age in individuals without known lung disease. The definition of chronic airway disease may need to be reconsidered to allow for normal ageing and ensure that people likely to benefit from interventions are identified rather than healthy people who may be harmed by potential overdiagnosis and overtreatment. The first step would be to apply age, sex and ethnicity-adjusted FEV1/FVC thresholds to the disease definition of chronic obstructive pulmonary disease.
PROSPERO registration number CRD42018087066.
- age-related decline
- lung function tests
- cohort studies
- systematic review
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Contributors ETT was involved with devising the review methods, conducting electronic searches, screening of abstracts, data extraction, data analysis and interpretation and co-drafting of the review. MG was involved with devising the review methods, screening of abstracts, data extraction, data analysis and interpretation and co-drafting the review. KJLB was involved with devising the review methods, data analysis and interpretation and co-drafting the review. SES was involved with devising the review methods, data analysis and interpretation and co-drafting the review. PG was involved with devising the review methods, data analysis and interpretation and co-drafting the review.
Funding KJLB and PG have received funding from the Australian National Health and Medical Research Council (Centre for Research Excellence Grant No 1104136, Australia Fellowship No 527500 and Program Grant No 633003). The funders had no role in design and conduct of the study; collection, management, analysis and interpretation of the data; and preparation, review or approval of the manuscript.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.
Author note This manuscript was prepared in accordance with the PRISMA statement and the MOOSE reporting guidelines.
Patient consent for publication Not required.
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