Hyperkyphosis and mortality risk in older men: The osteoporotic fractures in men study

Abstract

Introduction: Hyperkyphosis commonly affects older people but is not widely acknowledged as a clinically actionable problem, especially in men. There are several techniques to quantify kyphosis including the blocks and Cobb angle measurements. This study includes both kyphosis measures to investigate whether older men with accentuated kyphosis may be at increased mortality risk.

Methods: Men aged ≥65 years (N = 5994) were recruited to participate in the MrOS prospective cohort study from 2000 to 2002 (baseline). Our primary cohort included 2931 enrollees (mean age 79.3 years; SD 5.2) who underwent blocks-measured kyphosis from 2006 to 2009. Our secondary cohort included 2351 participants who underwent radiographic Cobb angle measurements at baseline. Cox proportional hazards analyses were used to determine association between kyphosis and all-cause mortality while adjusting for prevalent radiographic vertebral fractures, bone mineral density, incident fractures, gait speed, timed chair stands, self-reported health, alcohol use, medical co-morbidities, and physical activity.

Results: During a mean follow-up of 8.3 (SD 3.2) years, 1393 participants died in the primary cohort. In this group, compared to men with 0-1 block kyphosis, increasing blocks-measured kyphosis was associated with increased mortality (HR: 1.26-1.53, p trend <0.001). With addition of prevalent vertebral fracture to adjusted models, the association remained significant in participants with severe kyphosis (3+ blocks-measured). Similarly, with addition of chair stand performance the association remained significant for 4+ blocks kyphosis. Walking speed did not attenuate the association of kyphosis and mortality. In the secondary cohort, there were no significant associations between radiographic Cobb angle kyphosis and mortality.

Conclusions: Increasing blocks-measured kyphosis was associated with a greater risk of mortality in older men, indicating that hyperkyphosis identified on physical exam should be considered a clinically significant finding that may warrant further evaluation and treatment.

Keywords: hyper; kyphosis; mortality.

Figure 1.

Participant flow chart

Figure 2.

Measure of hyperkyphotic posture. A: Normal spine with neutral head and neck position. B: Kyphotic spine with hyperextended neck position. C: Kyphotic spine with head on blocks restores neutral head and neck position. Modified from Kado et al., (2004).

Figure 3.

Blocks kyphosis and all-cause mortality