Table 1 Baseline characteristics of the study population
Characteristic | First Period (July 2003 to September 2005) | Second Period (October 2005 to December 2007) | Difference (p value of the test of difference) |
|---|---|---|---|
Mean age (years) | 65.6 (9.5) | 67.6 (9.5) | 2 (<0.0001) |
NSAID use (%) | 31% | 25% | 6% (0.08) |
Vitamin D use (%) | 81% | 86% | 5% (0.1) |
Calcium use (%) | 80% | 75% | 5% (0.17) |
Estrogen use (%) | 6% | 9% | 3% (0.16) |