Table 1. Characteristics of all participants (n = 1,142; age, 40–59 years)* by sex-specific quartiles of serum LDL cholesterol in the INTERLIPID study in Japan, 1996–1999.
| Men (n = 572) |
|||||
|---|---|---|---|---|---|
| Q1 (n = 137) | Q2 (n = 147) | Q3 (n = 144) | Q4 (n = 144) | P value | |
| Serum LDL cholesterol, median (range), mg/dL | 88.0 (45–99) | 110 (100–119) | 129 (120–141) | 155 (142–201) | |
| Serum LDL cholesterol, mean (SD), mg/dL | 84.0 (13.1) | 109.3 (5.9) | 129.7 (6.4) | 157.3 (12.3) | |
| Age, mean (SD), years | 49.9 (5.3) | 49.3 (5.5) | 49.7 (5.5) | 49.2 (4.9) | 0.605 |
| BMI, mean (SD), kg/m2 | 23.0 (2.4) | 23.5 (2.9) | 23.7 (2.8) | 24.5 (2.5) | < 0.001 |
| Employed in a company***, no. (%) | 129 (94.2) | 131 (89.1) | 130 (90.3) | 136 (94.4) | 0.235 |
| Education***, mean (SD), years | 12.3 (2.3) | 12.1 (2.1) | 12.5 (2.2) | 12.4 (1.9) | 0.342 |
| Education years ≥ 12 years (finished high school)***, no. (%) | 111 (81.0) | 113 (76.9) | 122 (84.7) | 127 (88.2) | 0.066 |
| Site, no. (%) | 0.003 | ||||
| Toyama | 34 (24.8) | 34 (23.5) | 36 (25.4) | 44 (30.8) | |
| Sapporo | 53 (38.7) | 39 (26.9) | 35 (24.7) | 20 (14.0) | |
| Aito | 22 (16.1) | 33 (22.8) | 37 (26.1) | 36 (25.2) | |
| Wakayama | 28 (20.4) | 39 (26.9) | 34 (23.9) | 43 (30.1) | |
| Smokers***, no. (%) | 69 (50.4) | 77 (52.4) | 65 (45.1) | 85 (59.0) | 0.127 |
| Numbers of cigarettes, mean (SD), n/day | 10.6 (11.9) | 11.8 (13.4) | 11.0 (13.8) | 13.6 (13.5) | 0.222 |
| Numbers of cigarettes in smokers, mean (SD), n/day | 21.0 (7.8) | 22.4 (10.2) | 24.3 (9.8) | 23.0 (9.6) | 0.175 |
| Drinkers***, no. (%) | 134 (97.8) | 145 (98.6) | 137 (95.1) | 138 (95.8) | 0.283** |
| Alcohol intake, mean (SD), %kcal | 10.5 (7.5) | 9.6 (7.5) | 7.9 (7.2) | 8.6 (6.7) | 0.017 |
| Alcohol intake in drinkers, mean (SD), %kcal | 10.7 (7.5) | 9.8 (7.5) | 8.3 (7.2) | 8.9 (6.6) | 0.038 |
| Alcohol intake, mean (SD), g/day | 34.7 (24.9) | 31.4 (24.7) | 26.0 (25.1) | 28.4 (23.8) | 0.025 |
| Alcohol intake in drinkers, mean (SD), g/day | 35.4 (24.6) | 31.8 (24.6) | 27.3 (25.0) | 29.7 (23.6) | 0.051 |
| Dietary energy, mean (SD), kcal/day | 2317 (371) | 2270 (429) | 2263 (448) | 2268 (455) | 0.633 |
| Dietary total carbohydrate, mean (SD), %kcal | 51.1 (8.1) | 52.1 (7.9) | 52.9 (7.2) | 52.9 (7.7) | 0.187 |
| Dietary total protein, mean (SD), %kcal | 15.8 (2.4) | 15.8 (2.3) | 15.9 (2.2) | 15.7 (2.2) | 0.785 |
| Dietary total fat, mean (SD), %kcal | 23.8 (5.0) | 23.4 (4.6) | 23.9 (4.9) | 23.5 (4.7) | 0.819 |
| Dietary cholesterol, mean (SD), mg/1000 kcal | 200.6 (72.7) | 201.9 (67.1) | 198.4 (66.7) | 181.2 (61.2) | 0.020 |
| SFA, mean (SD), %kcal | 6.0 (1.7) | 6.1 (1.6) | 6.0 (1.5) | 6.1 (1.6) | 0.945 |
| PUFA, mean (SD), %kcal | 6.4 (1.6) | 6.0 (1.4) | 6.3 (1.6) | 6.1 (1.4) | 0.136 |
| MUFA, mean (SD), %kcal | 8.6 (2.1) | 8.5 (2.0) | 8.7 (2.2) | 8.5 (2.0) | 0.928 |
| TFA, mean (SD), %kcal | 0.3 (0.2) | 0.4 (0.2) | 0.4 (0.2) | 0.3 (0.2) | 0.018 |
| Total fiber, mean (SD), g/1000 kcal | 7.0 (2.0) | 6.4 (1.8) | 7.2 (1.9) | 6.8 (1.7) | 0.002 |
| Soluble fiber, mean (SD), g/1000 kcal | 1.1 (0.4) | 1.1 (0.4) | 1.2 (0.5) | 1.1 (0.4) | 0.008 |
| Insoluble fiber, mean (SD), g/1000kcal | 5.8 (1.7) | 5.3 (1.4) | 5.9 (1.5) | 5.6 (1.4) | 0.003 |
| Keys score, mean (SD) | 28.6 (6.1) | 29.3 (5.8) | 28.7 (6.0) | 28.3 (5.8) | 0.565 |
| Serum total cholesterol, mean (SD), mg/dL | 169.2 (18.8) | 189.3 (17.6) | 206.5 (16.7) | 230.8 (19.0) | < 0.001 |
| Serum HDL cholesterol, mean (SD), mg/dL | 56.9 (16.9) | 52.1 (13.6) | 53.5 (12.1) | 52.3 (11.2) | 0.040 |
| Serum TG, mean (SD), mg/dL | 155.2 (142.8) | 666.9 (127.2) | 155.5 (86.3) | 166.5 (80.4) | 0.619 |
| SBP, mean (SD), mmHg | 119.7 (11.1) | 118.1 (12.6) | 120.5 (13.0) | 123.2 (14.4) | 0.017 |
| DBP, mean (SD), mmHg | 75.3 (8.5) | 75.7 (9.8) | 76.3 (9.4) | 79.9 (11.4) | < 0.001 |
| On special diet***, no. (%) | 7 (5.1) | 7 (4.8) | 11 (7.6) | 6 (4.2) | 0.578 |
| On lipid-lowering drugs***, no. (%) | 3 (2.2) | 7 (4.8) | 2 (1.4) | 6 (4.2) | 0.308** |
| Women (n = 570) |
|||||
|---|---|---|---|---|---|
| Q1 (n = 141) | Q2 (n = 139) | Q3 (n = 148) | Q4 (n = 142) | P value | |
| Serum LDL cholesterol, median (range), mg/dL | 91 (39–101) | 113 (102–122) | 132 (123–142) | 160 (143–213) | |
| Serum LDL cholesterol, mean (SD), mg/dL | 86.8 (11.6) | 112.5 (5.8) | 132.1 (5.5) | 163.0 (17.4) | |
| Age, mean (SD), years | 47.4 (5.2) | 48.7 (5.2) | 49.5 (5.3) | 51.4 (4.7) | < 0.001 |
| BMI, mean (SD), kg/m2 | 22.3 (2.8) | 22.9 (2.8) | 23.3 (3.1) | 24.1 (3.4) | < 0.001 |
| Employed in a company***, no. (%) | 110 (78.0) | 107 (77.0) | 103 (69.6) | 99 (69.7) | 0.209 |
| Education***, mean (SD), years | 12.3 (2.1) | 11.8 (1.8) | 11.5 (1.9) | 10.9 (1.9) | < 0.001 |
| Education years ≥ 12 years (finished high school)***, no. (%) | 116 (82.3) | 104 (74.8) | 103 (69.6) | 73 (51.4) | < 0.001 |
| Site, no. (%) | 0.029 | ||||
| Toyama | 35 (25.0) | 32 (23.0) | 43 (29.1) | 39 (28.1) | |
| Sapporo | 52 (37.1) | 37 (26.6) | 27 (18.2) | 30 (21.6) | |
| Aito | 25 (17.9) | 38 (27.3) | 36 (24.3) | 30 (21.6) | |
| Wakayama | 28 (20.0) | 32 (23.0) | 42 (28.4) | 40 (28.8) | |
| Before menopause (women)***, no. (%) | 85 (60.3) | 68 (48.9) | 59 (39.9) | 41 (28.9) | < 0.001 |
| Smokers***, no. (%) | 14 (9.9) | 11 (7.9) | 10 (6.8) | 14 (9.9) | 0.723 |
| Numbers of cigarettes, mean (SD), n/day | 1.2 (4.4) | 0.9 (3.5) | 0.6 (2.7) | 1.3 (4.4) | 0.329 |
| Numbers of cigarettes in smokers, mean (SD), n/day | 12.2 (7.7) | 11.1 (6.8) | 8.9 (6.3) | 12.9 (7.0) | 0.538 |
| Drinkers***, no. (%) | 124 (87.9) | 113 (81.3) | 118 (79.7) | 114 (80.3) | 0.236 |
| Alcohol intake, mean (SD), %kcal | 2.3 (4.4) | 1.2 (2.8) | 1.4 (2.9) | 1.1 (2.0) | 0.032 |
| Alcohol intake in drinkers, mean (SD), %kcal | 2.6 (4.6) | 1.6 (3.1) | 1.7 (3.1) | 1.4 (2.1) | 0.057 |
| Alcohol intake, mean (SD), g/day | 6.1 (11.2) | 3.3 (7.1) | 3.5 (7.4) | 2.9 (5.3) | 0.028 |
| Alcohol intake in drinkers, mean (SD), g/day | 6.9 (11.7) | 4.1 (7.7) | 4.4 (8.0) | 3.6 (5.7) | 0.053 |
| Dietary energy, mean (SD), kcal/day | 1848 (367) | 1823 (310) | 1754 (296) | 1764 (308) | 0.041 |
| Dietary total carbohydrate, mean (SD), %kcal | 55.3 (7.4) | 56.5 (6.1) | 56.2 (6.2) | 56.7 (5.7) | 0.323 |
| Dietary total protein, mean (SD), %kcal | 16.1 (2.5) | 16.1 (2.1) | 16.2 (2.5) | 16.1 (2.0) | 0.938 |
| Dietary total fat, mean (SD), %kcal | 26.4 (5.3) | 26.1 (4.9) | 26.0 (4.5) | 26.0 (4.8) | 0.907 |
| Dietary cholesterol, mean (SD), mg/1000 kcal | 211.1 (75.4) | 195.2 (58.4) | 190.3 (61.8) | 198.9 (68.1) | 0.079 |
| SFA, mean (SD), %kcal | 7.0 (1.9) | 7.2 (1.8) | 7.0 (1.7) | 7.1 (1.8) | 0.880 |
| PUFA, mean (SD), %kcal | 6.7 (1.5) | 6.6 (1.5) | 6.6 (1.3) | 6.6 (1.4) | 0.854 |
| MUFA, mean (SD), %kcal | 9.6 (2.3) | 9.3 (2.2) | 9.4 (2.1) | 9.3 (2.1) | 0.741 |
| TFA, mean (SD), %kcal | 0.5 (0.4) | 0.5 (0.3) | 0.5 (0.3) | 0.5 (0.3) | 0.993 |
| Total fiber, mean (SD), g/1000 kcal | 8.5 (2.2) | 9.0 (2.2) | 9.1 (2.5) | 8.8 (2.2) | 0.146 |
| Soluble fiber, mean (SD), g/1000 kcal | 1.5 (0.5) | 1.6 (0.5) | 1.6 (0.6) | 1.5 (0.5) | 0.201 |
| Insoluble fiber, mean (SD), g/1000 kcal | 7.0 (1.7) | 7.4 (1.7) | 7.4 (2.0) | 7.2 (1.8) | 0.126 |
| Keys score, mean (SD) | 31.1 (6.7) | 31.2 (6.0) | 30.5 (6.5) | 31.1 (6.7) | 0.704 |
| Serum total cholesterol, mean (SD), mg/dL | 169.9 (21.5) | 191.6 (14.5) | 210.0 (16.0) | 237.0 (21.9) | < 0.001 |
| Serum HDL cholesterol, mean (SD), mg/dL | 62.1 (17.1) | 62.2 (14.3) | 60.3 (13.3) | 55.6 (10.7) | < 0.001 |
| Serum TG, mean (SD), mg/dL | 97.4 (69.8) | 100.9 (50.3) | 110.8 (52.0) | 133.2 (63.7) | < 0.001 |
| SBP, mean (SD), mmHg | 110.8 (13.0) | 113.0 (11.5) | 114.4 (14.5) | 118.2 (15.4) | < 0.001 |
| DBP, mean (SD), mmHg | 67.7 (8.8) | 70.1 (8.6) | 70.9 (9.7) | 73.2 (10.5) | < 0.001 |
| On special diet***, no. (%) | 9 (6.4) | 10 (7.2) | 13 (8.8) | 13 (9.2) | 0.800 |
| Taking lipid-lowering drugs***, no. (%) | 4 (2.8) | 5 (3.6) | 3 (2.0) | 7 (4.9) | 0.562** |
*
Excluded missing data for serum LDL cholesterol (n = 3). P values were obtained using Welch's ANOVA test or chi-squared test
**
Fisher's exact test.
***
Self-reported. SI conversion factors: to convert serum cholesterol to mmol/L, multiply values by 0.0259.
Keys score = 2.7 × S − 1.35 × P + 1.5 × √C; S, saturated fatty acid (%kcal); P, polyunsaturated fatty acid (%kcal); C, dietary cholesterol (mg/1,000 kcal).