Effects of body composition and adipose tissue distribution on respiratory function in elderly men and women: the Health, Aging and Body Composition Study.

Background: Previous cross-sectional studies demonstrate positive associations of fat free mass (FFM) and negative associations of centrally distributed fat deposits with respiratory function in older adults. Few studies have evaluated whether greater losses of muscle and increases in fat are associated with more rapid decline in respiratory function in aging. Methods: 957 men and 1024 women aged respectively 73.6 ± 2.8y and 73.2 ± 2.8y at baseline were followed for 5 years. Body weight, waist circumference, bone mineral density, FFM, fat mass (FM) and fat mass percentage (FM%) as measured by DXA, abdominal subcutaneous (SCAT) and visceral adipose tissue (VAT), thigh muscle area, thigh intermuscular fat (IMF) by CT and FEV1 and FVC were evaluated at baseline and after 5-years follow-up. Results: Cross-sectional analyses showed that height and thigh muscle area were positively and VAT negatively related to FEV1 and FVC. Increase in FM over five years was associated with concurrent FEV1 and FVC decline. In analyses stratified by weight-change categories, men and women who gained weight (vs. stable/lost weight) had more rapid declines in FEV1 and FVC. Conclusion: In this well-functioning cohort, less muscle and greater abdominal fat were each associated with poorer lung spirometry cross-sectionally, while increase in FM over five years was associated with concurrent FEV1 and FVC decline. Weight gain and accompanying fat deposition may accelerate age-related declines in respiratory function.