Table 1 General characteristics of the study subjects, N (%)
From: Dietary calcium intake and the risk of colorectal cancer: a case control study
|  | Men (n = 2496) | Women (n = 1192) | ||||
|---|---|---|---|---|---|---|
Case | Control | P-valuea | Case | Control | P-value | |
(n = 624) | (n = 1872) | (n = 298) | (n = 894) | |||
Age group (years) | Â | Â | Â | Â | Â | Â |
 −49 | 128(20.5) | 461(24.6) | <0.001 | 82(27.5) | 246(27.5) | >0.999 |
 50–59 | 226(36.2) | 815(43.5) |  | 111(37.3) | 333(37.3) |  |
 60+ | 270(43.3) | 596(31.8) |  | 105(35.2) | 315(35.2) |  |
Marital status | Â | Â | Â | Â | Â | Â |
 Married | 556(89.1) | 1671(89.3) | 0.262 | 216(72.5) | 697(78.0) | 0.028 |
 Single | 66(10.6) | 167(8.9) |  | 80(26.9) | 184(20.6) |  |
 Missing | 2(0.3) | 34(1.8) |  | 2(0.7) | 13(1.5) |  |
Education level | Â | Â | Â | Â | Â | Â |
 Less than middle school | 183(29.3) | 250(13.4) | <0.001 | 138(46.3) | 146(16.3) | <0.001 |
 High school | 265(42.5) | 498(26.6) |  | 103(34.6) | 365(40.8) |  |
 College or more | 176(28.2) | 1024(54.7) |  | 57(19.1) | 332(37.1) |  |
 Missing | 0(0.0) | 100(5.3) |  | 0(0.0) | 51(5.7) |  |
Household income (10000 won/month) | Â | Â | Â | Â | Â | Â |
 <200 | 222(35.6) | 348(18.6) | <0.001 | 99(33.2) | 212(23.7) | 0.016 |
 200–400 | 252(40.4) | 727(38.8) |  | 134(45.0) | 313(35.0) |  |
 >400 | 150(24.0) | 588(31.4) |  | 65(21.8) | 230(25.7) |  |
 Missing | 0(0.0) | 209(11.2) |  | 0(0.0) | 139(15.6) |  |
Body mass index (kg/m2) | Â | Â | Â | Â | Â | Â |
 <25 | 431(69.1) | 1136(60.7) | <0.001 | 207(69.5) | 661(73.9) | 0.133 |
 ≥25 | 192(30.8) | 736(39.3) |  | 91(30.5) | 233(26.1) |  |
 Missing | 1(0.2) | 0(0.0) |  | 0(0.0) | 0(0.0) |  |
Smoking status | Â | Â | Â | Â | Â | Â |
 Non-smoker | 145(23.2) | 391(20.9) | 0.418 | 264(88.6) | 854(95.5) | <0.001 |
 Ex-smoker | 302(48.4) | 951(50.8) |  | 15(5.0) | 21(2.4) |  |
 Current smoker | 177(28.4) | 530(28.3) |  | 19(6.4) | 18(2.0) |  |
 Missing | 0(0.0) | 0(0.0) |  | 0(0.0) | 1(0.1) |  |
Alcohol consumption | Â | Â | Â | Â | Â | Â |
 Non-drinker | 107(17.2) | 308(16.5) | <0.001 | 172(57.7) | 567(63.4) | 0.031 |
 Ex-drinker | 103(16.5) | 201(10.7) |  | 26(8.7) | 44(4.9) |  |
 Current drinker | 414(66.4) | 1360(72.7) |  | 100(33.5) | 282(31.5) |  |
 Missing | 0(0.0) | 3(0.2) |  | 0(0.0) | 1(0.1) |  |
Regular exercise | Â | Â | Â | Â | Â | Â |
 No | 388(62.2) | 786(42.0) | <0.001 | 225(75.5) | 403(45.1) | <0.001 |
 Yes | 236(37.8) | 1073(57.3) |  | 73(24.5) | 488(54.6) |  |
 Missing | 0(0.0) | 13(0.7) |  | 0(0.0) | 3(0.3) |  |
Family history of cancer | Â | Â | Â | Â | Â | Â |
 No | 391(62.7) | 1016(54.3) | <0.001 | 171(57.4) | 446(49.9) | 0.038 |
 Yes | 233(37.3) | 846(45.2) |  | 127(42.6) | 438(49.0) |  |
 Missing | 0(0.0) | 10(0.5) |  | 0(0.0) | 10(1.1) |  |
Family history of colorectal cancer | Â | Â | Â | Â | Â | Â |
 No | 559(89.6) | 1768(94.4) | <0.001 | 277(93.0) | 816(91.3) | 0.715 |
 Yes | 65(10.4) | 94(5.0) |  | 21(7.1) | 68(7.6) |  |
 Missing | 0(0.0) | 10(0.5) |  | 0(0.0) | 10(1.1) |  |
Calcium supplement use within 2Â years | Â | Â | Â | Â | Â | Â |
 No | 621(99.5) | 1807(96.5) | <0.001 | 290(97.3) | 729(81.5) | <0.001 |
 Yes | 3(0.5) | 65(3.5) |  | 8(2.7) | 165(18.5) |  |
Total energy intake (kcal/day), Mean (SD) | 2210.4(514.4) | 1811.4(553.4) | <0.001 | 1885.9(534.3) | 1674.3(604.4) | <0.001 |
Total calcium intake (mg/day), Mean (SD) | 463.7(211.2) | 450.8(248.6) | 0.207 | 474.7(248.0) | 536.8(335.1) | <0.001 |