Low Lung Function in Middle-Aged Smokers Impacts Health Status, Morbidities, and Mortality: An Observational Analysis of the Lovelace Smokers Cohort.

Abstract

Background: Pulmonary function tests may predict future outcomes; however, they are not often performed in middle-aged individuals at risk for future airway obstruction. We examined whether smokers with low lung function (LLF) have an increased risk of developing health problems and mortality over time.

Methods: Current and ever smokers (n=830) from the Lovelace Cohort aged 40-60 years without baseline airway obstruction and with at least 2 spirometry measurements over 18 months were included. Participants were divided into high lung function (HLF) and LLF function tertiles based on forced expiratory volume in 1 second percentage predicted (FEV₁%pred). Lung function, health status, and comorbidities were compared at baseline and over 17 years; mortality at 17 years was also assessed. From these participants, 61 HLF (baseline FEV1%pred >99%) and 26 LLF (baseline FEV1%pred <88%) were examined at 17 years follow-up using logistic regression.

Results: Baseline demographic and clinical characteristics were generally similar between the LLF and HLF tertiles, except for age, sex, body mass index, and lung function. In the overall cohort (LLF, n=277; HLF, n=277), survival of the HLF versus LLF cohort showed a hazard ratio of 0.49 (p=0.02). At the 17-year follow-up, LLF was associated with increased prevalence of wheeze, cardiovascular diseases, chronic lung diseases, diabetes, and worse health status.

Conclusions: Smokers with LLF without airflow obstruction exhibited reduced survival and an increased risk for development of chronic morbidities. Thus, spirometry may be used to identify at-risk individuals, allowing for early preventative interventions that can improve long-term health outcomes. Take home message: Among ever smokers without airflow obstruction, LLF is associated with increased mortality and poor health status. Spirometry may identify at-risk patients, enabling early emphasis on interventions with the potential to improve long-term health outcomes.