Table 2.
Characteristics of the Study Sample and Distribution of Independent Variables by IHD Status at Baseline, Kuopio Ischemic Heart Disease Risk Factor Study, 1986-2001 (N = 621)
| Variable | Men Without IHD (n = 542) | Men With IHD (n = 79) | P valuea |
|---|---|---|---|
| Age and technical factors | |||
| Mean (SD) age at baseline, y | 49.1 (5.9) | 52.3 (5.5) | .001 |
| Mean (SD) log of maximum IMT at baseline, log mm | −.013 (0.19) | −.052 (0.25) | .011 |
| Sonographer at 11-year follow-up,b n (%) | |||
| A | 19 (3.5) | 2 (2.5) | .577 |
| B | 6 (1.1) | 0 | |
| C | 517 (95.4) | 77 (97.5) | |
| Participation in lipid-lowering drug trial, n (%) | |||
| Placebo group | 37 (6.8) | 6 (7.6) | .802 |
| Treatment group | 34 (6.3) | 6 (7.6) | .655 |
| Biological factors | |||
| Mean (SD) blood glucose level, mmol/Lc | 4.9 (0.9) | 4.9 (0.7) | .808 |
| Mean (SD) plasma fibrinogen level, g/Lc | 3.0 (0.5) | 3.1 (0.5) | .025 |
| Mean (SD) BMI at baseline, kg/m2 | 26.5 (3.2) | 26.8 (3.3) | .405 |
| Mean (SD) LDL cholesterol at baseline, mmol/L | 3.8 (0.9) | 3.9 (1.0) | .232 |
| Mean (SD) HDL cholesterol at baseline, mmol/L | 1.3 (0.3) | 1.3 (0.3) | .634 |
| Mean (SD) SBP at baseline, mm Hg | 131 (15) | 127 (15) | .017 |
| Mean (SD) proportion of follow-up time taking lipid-lowering medication | 0.01 (0.07) | 0.04 (0.13) | .061 |
| Mean (SD) proportion of follow-up time taking blood pressure-lowering medication | 0.17 (0.32) | 0.33 (0.41) | .002 |
| Behavioral factors | |||
| Mean (SD) alcohol consumption, g/wkc | 77.3 (996.6) | 84.5 (110.1) | .543 |
| Smoking status, n (%) | |||
| Nonsmoker | 204 (37.6) | 28 (35.4) | .968 |
| Former smoker | 157 (29.0) | 23 (29.1) | |
| Irregular smoker | 41 (7.6) | 7 (8.9) | |
| Current smoker | 149 (25.8) | 21 (26.6) | |
| Mean (SD) conditioning LTPA, h/yc | 121 (103) | 120 (93) | .986 |
| Mean (SD) cardiorespiratory fitness, mL O2/kg/min | 34.3 (7.0) | 28.4 (6.8) | .001 |
| Socioeconomic status | |||
| Mean (SD) annual income, 1,000 FIMc | 12.0 (6.8) | 9.2 (4.5) | .001 |
| Psychosocial job factors | |||
| Mean (SD) social support at work score | 6.0 (2.3) | 5.7 (2.4) | .410 |
| Mean (SD) mental strain at work index | 11.8 (5.2) | 13.4 (5.4) | .014 |
| Stress from work deadlines, n (%) | 351 (64.8%) | 33 (58.2%) | .259 |
| Work time | |||
| Mean (SD) days/week at baseline | 5.2 (0.6) | 5.3 (0.8) | .161 |
| Mean (SD) hours/day at baseline | 8.0 (1.5) | 8.1 (1.6) | .438 |
| Mean (SD) hours/week at baseline | 41.9 (11.3) | 43.5 (13.2) | .201 |
| Employment intensity between baseline and 11-year follow-up | 0.70 (0.31) | 0.51 (0.32) | .001 |
| Mean (SD) hours worked per year employed between baseline and 11-year follow-up | 1,351 (708) | 993 (711) | .001 |
Abbreviations: IHD, ischemic heart disease; SD, standard deviation; IMT, intima-media thickness; BMI, body mass index; LDL, low-density lipoprotein; HDL, high-density lipoprotein; SBP, systolic blood pressure; LTPA, leisure-time physical activity; FIM, Finnish markka.
a
Calculated by using t tests or χ2 tests.
b
All ultrasound examinations were performed by the same sonographer at baseline.
c
Average of baseline, 4-year, and 11-year values.