CORRELATES OF KYPHOSIS IN OLDER WOMEN

OBJECTIVE: To determine the association between kyphosis (degree of fo rward curvature of the thoracic spine) and measures of spinal osteopor osis (height loss and vertebral fractures) and chronic back pain and d isability in older women. DESIGN: A cross-sectional study. SETTING: El even clinical centers in the United States. PARTICIPANTS: A total of 6 439 community-dwelling osteoporotic women aged 55-80 enrolled in the F racture Intervention Trial (FIT), a multicenter clinical trial of alen dronate. MEASUREMENTS: Thoracic curvature was measured at baseline usi ng a Debreuner Kyphometer. Height loss was determined by subtracting c urrent height measured with a Harpenden stadiometer from self-reported height at age 25. Vertebral fractures were defined by morphometry and semiquantitative reading of lateral thoracic and lumbar spine radiogr aphs, and chronic back pain and back-related disability were assessed by questionnaire. RESULTS: After adjustment for age, a 15 degrees incr ease in kyphosis was associated with losing more than 4 cm of height ( OR, 1.88; 95% CI, 1.79-2.03) and having a vertebral fracture (OR, 1.57 ; 95% CI, 1.46-1.69). Kyphosis was more strongly related to thoracic f ractures than to lumbar fractures, and kyphosis was most prominent in women with multiple thoracic wedge fractures. Kyphosis was also associ ated with upper back pain (OR per 15 degrees increase, 1.62; 95% CI 1. 47-1.79) and middle back pain (OR per 15 degrees increase, 1.24; 95% C I 1.12-1.36), but it was not related to lower back pain (OR per 15 deg rees increase, 0.98; 95% CI 0.90-1.05). Women with greater degrees of kyphosis were only slightly more likely to report back- related disabi lity (OR per 15 degrees increase, 1.18; 95% CI 1.03-1.35) and poorer h ealth status (OR per 15 degrees increase, 1.19; 95% CI 1.03-1.37). CON CLUSIONS: Older women with greater degrees of kyphosis are likely to h ave other manifestations of spinal osteoporosis such as height loss an d thoracic fractures and to suffer chronic upper and middle back pain. Measurement of kyphosis may be useful in assessing the severity of sp inal osteoporosis.