Severity of Kyphosis and Decline in Lung Function: The Framingham Study

Background: Hyperkyphosis reduces the amount of space in the chest, mobility of the rib cage, and expansion of the lungs. Decline in pulmonary function may be greater in persons with more severe kyphosis; however, no prospective studies have assessed this association. We conducted a longitudinal study to quantify the impact of kyphosis severity on decline in pulmonary function over 16 years in women and men. Methods: Participants included a convenience sample of 193 women and 82 men in the Framingham Study original cohort (mean age: 63 years; range: 50-79 years), who had measurements of kyphosis angle from lateral spine radiographs obtained in 1972-1976 and forced expiratory volume in 1 second (FEV1) from spirometry taken four times over 16 (+/- 1.87) years from 1972 through 1988. Results: Kyphosis severity was associated with greater decline in FEV 1 in women but not in men. Adjusted mean change in FEV 1 over 16 years was -162, -245, and -261 mL (trend, p=.02) with increasing tertile of kyphosis angle in women and -372, -297, and -257 mL (trend, p=.20) in men, respectively. Conclusions: This longitudinal study found that kyphosis severity increased subsequent decline in pulmonary function in women but not in men. Reasons for an association between kyphosis and pulmonary function in women but in not men may be due, at least in part, to the small number of men in our study. Nevertheless, our findings suggest that preventing or slowing kyphosis progression may reduce the burden of pulmonary decline in older adults.