Mediators of age-related lung function decline

Maintenance of lung function is an often under-appreciated, yet critical component of healthy aging. It naturally declines with age, doing so in the presence/absence of overt (eg. smoking), and non-overt (eg. demographics, lifestyle) factors. Although the majority of older Canadians are not exposed to overt factors, many non-overt factors are extremely prevalent and have a substantial impact on lung function. The primary goal of this project is to characterize the relationship between lung function and non-overt factors across multiple disciplines (ie. lifestyle, psychosocial, health and disease), and identify significant mediators of its age-related decline. We are also interested in investigating whether these relationships are also apparent for “healthy smokers,” individuals that currently smoke, but exhibit no loss of lung function.

Maintenance of lung health is an often underappreciated, yet critical component of healthy aging and optimal well-being. Given the unprecedented shift in the average age of Canadians over the next half century, it will be important to investigate the correlates of lung function and symptoms of poor lung health in older adults.

In our project we observed notable and significant associations for spirometric lung function (i.e. FEV1, FEV1/FVC) with respiratory disease, smoking, obesity, income, and physical activity, while psychosocial factors mainly exhibited non-significant associations. Generally, these associations were stronger for males than females, and adults 65 and older as compared to those aged 45-64. Interestingly though, even in the absence of impaired lung function, respiratory symptoms such as cough, shortness of breath and wheeze remain associated with poor overall health. In older adults with normal lung function, both respiratory symptoms and smoking were independently associated with frailty, the most substantial associations observed for those having at least one respiratory symptom and current smokers with > 10 pack-year exposure. However, the association between symptoms and frailty was even evident in never smokers. These results suggest that repiratory symptoms should not be simply regarded as a benign by-product of aging.