Vascular calcification in middle age and long-term risk of hip fracture: the Framingham Study

Abstract

Osteoporosis and atherosclerosis frequently occur in the same individuals and may share similar pathogenic mechanisms. This study examined the relation between severity of aortic calcification in middle-age years and subsequent risk of hip fracture in women and men in the population-based Framingham Study.

Introduction: We assessed vascular calcification in women and men in middle age and risk of hip fracture at advanced age.

Materials and methods: Participants included 2499 Framingham cohort members (mean age, 61 yr; range, 47-80 yr). Semiquantitative methods were used to determine severity of abdominal aortic calcification on baseline radiographs. Information on potential confounding factors was obtained from study examinations conducted at, or before, baseline radiography. Hip fractures were ascertained by active surveillance and confirmed by medical records.

Results: Thirty-five-year cumulative incidence of hip fracture was 16% in women and 5% in men with prevalent aortic calcification at baseline (score 1+) and 14% in women and 4% in men without aortic calcification (score 0). Hazard ratios (HRs) and 95% CIs for hip fracture did not increase from the lowest to the highest category of aortic calcification. HRs were 1.0, 1.2 (95% CI, 0.9-1.8), 1.2 (95% CI, 0.7-1.9), 1.1 (95% CI, 0.7-1.7), and 1.4 (95% CI, 0.8-2.3) in women (p for trend = 0.44) and 1.0, 1.8 (95% CI, 0.8-3.8), 1.8 (95% CI, 0.7-4.6), 1.5 (95% CI, 0.6-3.9), and 1.2 (95% CI, 0.2-5.7) in men (p for trend = 0.29) for aortic calcification scores 0 (reference), 1-4, 4-5, 6-10, and 11+, respectively. However, aortic calcification score was strongly associated with increased risk of death (p for trend < 0.0001 in women and men). HRs (95% CIs) for mortality from the lowest to highest aortic calcification score were 1.0, 1.6 (1.4-1.9), 1.7 (1.4-2.1), 1.8 (1.5-2.2), and 2.1 (1.7-2.6) for women, and for men were 1.0, 1.4 (1.1-1.6), 1.4 (1.2-1.8), 1.6 (1.3-2.0), and 1.9 (1.5-2.5).

Conclusions: Vascular calcification in middle-aged adults does not increase long-term hip fracture risk.

FIG. 1

Distribution of aortic calcification in 1453 women and 1046 men in The Framingham Study, 1967-70

FIG. 2

Cumulative incidence of hip fracture, 1967-70 through 2003, according to baseline aortic calcification score in 1453 women and 1046 men, The Framingham Study

FIG. 3

Multivariable-adjusted hazard ratios* for hip fracture in women (left) and men (right) according to aortic calcification score, The Framingham Study, 1967-70 through 2003 The y-axis is on a log scale. The reference group is aortic calcification score 0. Thebars denote 95 percent confidence intervals. * Models included baseline age, body mass index, systolic blood pressure, smoking, total cholesterol, diabetes, coronary heart disease, and estrogen use (in women).

FIG. 4

Multivariable-adjusted hazard ratios* for death in women (left) and men (right) according to aortic calcification score, The Framingham Study, 1967-70 through 2003 The y-axis is on a log scale. The reference group is aortic calcification score 0. Thebars denote 95 percent confidence intervals. * Models included baseline age, body mass index, systolic blood pressure, smoking, total cholesterol, diabetes, coronary heart disease, and estrogen use (in women).