Lung function in older humans: the contribution of body composition, physical activity and smoking

An allometric model was used to determine the important factors related to the decline in forced expiratory volume (FEV1.0) across ages 55-86 years in independently living men and women. Measurements were available from a ran domized sample of 181 men and 203 women residing in London, Ontario, Canada . The effects of height, age, sex, adiposity, fat free mass (FFM), grip str ength and physical activity (PA) on FEV1.0 were assessed using an allometri c model to test the hypothesis that sex differences in lung function would be due in part to sex-related differences in the aforementioned variables a nd would therefore be eliminated by our analysis. The following model was l inearized and parameters were identified using standard multiple regression : FEV1.0 = height(beta1) . FFMbeta2 . grip strength(beta3) . PA(beta4) . ex p (beta0 + beta 5age + beta 6sex + beta 7smoking + beta8% body fat) . is an element of. Results indicate that the amount of FFM and heavy intensity ph ysical activity participated in by the elderly may be more important in inf luencing forced expiratory function than previously recognized. In addition , results from this study have confirmed the importance of age and height i n the prediction of FEV1.0 and demonstrated a negative effect of smoking on lung function. Individuals with a greater FFM and physical activity level tended to be associated with an above average lung function performance. Th e cross-sectional rate of decline in FEV1.0 determined from our model was a pproximate to 12% per decade.