Table 1.
Participants’ baseline characteristics by quartiles of dietary copper intake
| Variables | Total (N = 45 101) | < 1.85 mg/d (N = 11 159) | 1.85–2.45 mg/d (N = 11 249) | 2.45–3.19 mg/d (N = 11 297) | > 3.19 mg/d (N = 11 396) |
|---|---|---|---|---|---|
| Copper, mg/d, mean ± SD | 2.6 ± 1.05 | 1.5 ± 0.28 | 2.1 ± 0.17 | 2.8 ± 0.21 | 4.1 ± 0.78 |
| Age, year, mean ± SD | 51.1 ± 9.65 | 52.3 ± 9.76 | 51.6 ± 9.65 | 50.9 ± 9.59 | 49.5 ± 9.39 |
| Men, N (%) | 18 847(41.8) | 3 524(31.6) | 4 333(38.5) | 5 012(44.4) | 5 978(52.5) |
| BMI, kg/m2, mean ± SD | 24.6 ± 3.66 | 24.3 ± 3.67 | 24.5 ± 3.65 | 24.7 ± 3.7 | 24.7 ± 3.62 |
| Rural, N (%) | 23 201(51.4) | 5 924(53.1) | 5 594(49.7) | 5 650(50) | 6 033(52.9) |
| Married, N (%) | 42 475(94.4) | 10 261(92.2) | 10 581(94.2) | 10 685(94.8) | 10 948(96.2) |
| Education, N (%) | |||||
| Low | 15 391(34.2) | 4 403(39.6) | 3 810(34) | 3 563(31.6) | 3 615(31.8) |
| Medium | 22 959(51) | 5 483(49.3) | 5 697(50.8) | 5 888(52.2) | 5 891(51.8) |
| High | 6 629(14.7) | 1 229(11.1) | 1 713(15.3) | 1 827(16.2) | 1 860(16.4) |
| Occupation, N (%) | |||||
| Professional/managers | 5 680(12.6) | 1 175(10.6) | 1 520(13.6) | 1 542(13.7) | 1 443(12.7) |
| Skilled workers | 1 5623(34.8) | 3 609(32.5) | 3 978(35.5) | 4 012(35.6) | 4 024(35.4) |
| Unskilled workers | 1 6014(35.6) | 3 618(32.6) | 3 631(32.4) | 4 086(36.3) | 4 679(41.2) |
| Homemaker | 7 628(17) | 2 710(24.4) | 2 078(18.5) | 1 631(14.5) | 1 209(10.6) |
| Current Smoker (%) | 12 198(27.5) | 2 374(21.8) | 2 912(26.3) | 3 184(28.6) | 3 728(33.1) |
| Current Drinker (%) | 10 924(24.5) | 2 095(19.2) | 2 587(23.2) | 2 875(25.7) | 3 367(29.9) |
| Physical activity, N (%) | |||||
| Low | 6 889(15.5) | 2 060(18.6) | 1 637(14.8) | 1 623(14.6) | 1 569(14) |
| Moderate | 1 8781(42.2) | 4 976(45) | 4 828(43.6) | 4 601(41.3) | 4 376(39.1) |
| High | 1 8791(42.3) | 4 011(36.3) | 4 616(41.7) | 4 927(44.2) | 5 237(46.8) |
| Hypertension, N (%) | 18 713(41.6) | 4 500(40.4) | 4 628(41.2) | 4 837(42.9) | 4 748(41.8) |
| History of diabetes, N (%) | 3 779(8.4) | 1 145(10.3) | 966(8.6) | 886(7.8) | 782(6.9) |
| History of CVD, N (%) | 3 791 (8.4) | 954 (8.5) | 993 (8.8) | 998 (8.8) | 846 (7.4) |
| Energy, kcal/day, mean ± SD | 1964 ± 667 | 1346 ± 394 | 1766 ± 426 | 2058 ± 441 | 2672 ± 559 |
| Composite outcome, N (%) | 5 608(12.4) | 1 353(12.1) | 1 343(11.9) | 1 434(12.7) | 1 478(13.0) |
| CVD incidence | 4 012(8.9) | 918(8.2) | 927(8.2) | 1 051(9.3) | 1 116(9.8) |
| Stroke incidence | 2 811(6.2) | 634(5.7) | 633(5.6) | 755(6.7) | 789(6.9) |
| MI incidence | 1 119(2.5) | 267(2.4) | 289(2.6) | 269(2.4) | 294(2.6) |
| HF incidence | 314(0.7) | 72(0.6) | 63(0.6) | 80(0.7) | 99(0.9) |
| All-cause mortality | 2 644(5.9) | 722(6.5) | 643(5.7) | 634(5.6) | 645(5.7) |
| CVD mortality | 955(2.1) | 273(2.4) | 201(1.8) | 236(2.1) | 245(2.1) |
BMI Body mass index, CVD Cardiovascular disease, HF Heart failure, MI Myocardial infarction