Table 2.
Characteristics of study populations
| Population 1 | Population 2 | |||||
|---|---|---|---|---|---|---|
| case (n = 808) | control (n = 829) | P value | case (n = 463) | control (n = 458) | P value | |
| age (year) | 60.36 ± 10.22 | 61.12 ± 12.01 | 0.166 | 54.06 ± 8.76 | 53.27 ± 9.06 | 0.175 |
| male | 634 (78.5%) | 647 (78.0%) | 0.837 | 335 (72.4%) | 332 (72.5%) | 0.963 |
| BMI (kg/m2) | 25.70 ± 3.28 | 24.97 ± 3.08 | <0.001 | 25.56 ± 3.26 | 24.20 ± 2.89 | <0.001 |
| smoking | 367 (45.4%) | 111 (13.4%) | <0.001 | 269 (58.1%) | 232 (50.7%) | <0.001 |
| Hypertension | 528 (65.3%) | 311 (37.5%) | <0.001 | 294 (63.5%) | 118 (25.8%) | <0.001 |
| diabetes mellitus | 225 (27.8%) | 104 (12.5%) | <0.001 | 125 (27.0%) | 30 (6.6%) | <0.001 |
| hyperlipidemia | 439 (54.3%) | 521 (62.8%) | <0.001 | 314 (67.8%) | 181 (39.5%) | <0.001 |
The data were presented as mean ± SEM (standard error of the mean) for age and BMI as well as No.(percentage) for other factors. P values for age and BMI were calculated from t-test comparing case and control groups within population. P values for gender, smoking, hypertension, diabetes mellitus, hyperlipidemia were calculated from Chi-square test within population. BMI: body mass index, which is calculated by body weight (Kg)/ height2 (m2)