The effects of adiposity and weight change on forced expiratory volume decline in a longitudinal study of adults

OBJECTIVE: To investigate whether changes in anthropometric measures are related to lung function decline. DESIGN: A national 7-y follow up study in Great Britain. SUBJECTS: 3391 adults aged 18-73 y at baseline. MEASUREMENTS: The primary outcome measure was change in forced expiratory volume in one second (Delta FEV1), adjusted for age, height and sex. This was related to changes in weight, body mass index, waist circumference, hips circumference and waist to hip ratio. RESULTS: Changes in weight, body mass and waist circumference, adjusted for confounders including mean level, were all associated with changes in FEV1 (P < 0.001), with all effects stronger in men than women (P < 0.05). Change in waist to hip ratio was related in men (P = 0.01), but not in women (P = 0.34). A 10 kg weight increase induced an additional fall in FEV1 of 96 ml (95% confidence interval (95% CI 65-127 ml) in men, and 51 ml (95% CI. 27-75 ml) in women. In men, the effect increased with average weight and obesity and was more pronounced in middle age. This phenomenon was not present in women, possibly due to gender differences in weight distribution in later adult life, Smoking did not appear to influence the magnitude of effect in either sex, The detrimental effect of weight gain on FEV1 in subjects that stopped smoking between studies appeared small in comparison to the benefit of smoking cessation. CONCLUSION: Increases in adult body mass are predictors of FEV1 decline, especially among older and heavier men, where weight reduction may significantly slow lung function decline.