Relationship between low bone mineral density and exercise-induced myocardial ischemia.

OBJECTIVE

To evaluate the relationship between bone mineral density (BMD) and ischemic heart disease and exercise capacity, as assessed by stress testing.

PATIENTS AND METHODS

We retrospectively reviewed entries in the echocardiography database for 28,048 consecutive patients who underwent exercise echocardiography for standard clinical indications between August 1, 1998, and October 1, 2003, to determine which of these patients had also undergone dual-energy x-ray absorptiometry to measure femoral neck BMD before the procedure. Of the 1194 patients meeting both criteria, 28 were excluded because of missing data and 24 because they were tested with an exercise protocol other than the Bruce protocol, leaving 1142 patients to be included.

RESULTS

Of the included study patients, 643 (56%) had a T score of -1.0 or less (mean age +/- SD, 67 +/- 0 years; 87% women), and 499 (44%) had a T score greater than -1.0 (60 +/- 10 years; 90% women). For every 1-unit decrease in femoral neck T score, a 0.23 minute decrease in treadmill exercise duration was observed, once values had been adjusted for age and other patient characteristics (95% confidence interval [CI], 0.11-0.35; P<.001). Furthermore, for every 1-unit decrease in T score, there was a 22% increased risk of myocardial ischemia after adjustments (hazard ratio, 1.22; 95% CI, 1.06-1.41; P=.004). Overall, after adjustments, patients with a BMD of -1.0 or less who were referred for exercise echocardiography had a 43% greater risk of myocardial ischemia than did patients referred with normal BMD (hazard ratio, 1.43; 95% CI, 1.06-1.94; P=.02).

CONCLUSIONS

Lower BMD is associated with myocardial ischemia and decreased exercise capacity during exercise echocardiography. Persons with low BMD who present with symptoms suggestive of cardiovascular disease are more likely to have myocardial ischemia than are those with normal BMD.