Table 1.
Descriptive characteristics of the study population by breast cancer cases and its molecular subtypes compared to controls, the Nigerian Integrative Epidemiology of Breast Cancer Study(NIBBLE), years 2014–2016.
| Breast Cancer Cases |
|||||||
|---|---|---|---|---|---|---|---|
| N = 1400 | Controls N = 892 N (%) / Mean ± SD |
Total Cases N = 508 N (%) / Mean ± SD |
p-value a | Hormone Receptor Positive (HRP) (ER+/PR+) N = 127 N (%) / Mean ± SD |
p-value a | Triple-Negative (TNBC) (ER−, PR−, HER2−) N = 123 N (%) / Mean ± SD |
p-value a |
|
| |||||||
| Age, years | 40.1 ± 9.0 | 45.5 ± 11.1 | < 0.001 | 45.5 ± 8.9 | < 0.001 | 46.7 ± 12.6 | < 0.001 |
| Age at first menstrual period, years | 14.4 ± 2.0 | 14.3 ± 1.7 | 0.450 | 14.3 ± 1.6 | 0.713 | 14.2 ± 1.7 | 0.231 |
| Education | < 0.001 | < 0.001 | < 0.001 | ||||
| Elementary≤ | 136(15.2) | 146(28.7) | 39(30.7) | 42(34.2) | |||
| Completed HS | 239(26.8) | 103(20.3) | 18(14.2) | 21(17.1) | |||
| Post HS no University | 209(23.4) | 125(24.6) | 37(29.1) | 29(23.6) | |||
| Completed University | 304(34.1) | 115(22.6) | 29(22.8) | 29(23.6) | |||
| Missing | 4(0.5) | 19(3.7) | 4(3.2) | 2(1.5) | |||
| Marital status | < 0.001 | 0.017 | < 0.001 | ||||
| Married | 633(71.0) | 351(69,1) | 91(71.7) | 88(71.6) | |||
| Single | 157(17.6) | 54(10.6) | 11(8.6) | 10(8.1) | |||
| Separated/Divorced/Widowed | 100(11.2) | 84(16.6) | 21(16.5) | 23(18.7) | |||
| Missing | 2(0.2) | 19(3.7) | 4(3.2) | 2(1.6) | |||
| Occupation | < 0.001 | < 0.001 | < 0.001 | ||||
| Self-Employed | 97(10.9) | 135(26.6) | 29(22.8) | 42(34.2) | |||
| Unskilled Manual | 483(54.2) | 203(40.0) | 49(38.6) | 46(37.4) | |||
| Skilled Manual | 150(16.8) | 116(22.8) | 32(25.2) | 28(22.8) | |||
| Professional/Executive | 127(14.2) | 24(4.7) | 6(4.7) | 3(2.4) | |||
| Missing | 35(3.9) | 30(5.9) | 11(8.7) | 4(3.2) | |||
| Wealth Index | 0.001 | 0.011 | 0.543 | ||||
| Low | 356(39.9) | 190(37.4) | 45(35.4) | 55(44.7) | |||
| Middle | 232(26.0) | 171(33.7) | 47(37.1) | 42(34.2) | |||
| High | 293(32.9) | 123(24.2) | 29(22.8) | 22(17.9) | |||
| Missing | 11(1.2) | 24(4.7) | 6(4.7) | 4(3.3) | |||
| Ever used oral contraceptives | 0.127 | 0.138 | 0.154 | ||||
| Yes | 298(33.4) | 144(28.4) | 33(26.0) | 33(26.8) | |||
| No | 584(65.5) | 340(66.9) | 89(70.0) | 88(71.6) | |||
| Missing | 10(1.1) | 24(4.7) | 5(4.0) | 2(1.6) | |||
| Parity | 0.009 | 0.110 | 0.074 | ||||
| 0 | 117(13.1) | 50(9.8) | 10(7.9) | 14(11.4) | |||
| 1–2 | 204(22.9) | 86(16.9) | 21(16.5) | 25(20.3) | |||
| 3–5 | 409(45.9) | 237(46.7) | 62(48.8) | 48(39.0) | |||
| ≥ 6 | 155(17.4) | 111(21.9) | 28(22.1) | 33(26.8) | |||
| Missing | 7(0.8) | 24(4.7) | 6(4.7) | 3(2.5) | |||
| Menopausal status | < 0.001 | < 0.001 | < 0.001 | ||||
| Postmenopausal | 179(20.1) | 185(36.4) | 42(33.1) | 51(41.6) | |||
| Premenopausal | 708(79.4) | 304(59.8) | 81(63.8) | 70(56.9) | |||
| Missing | 5(0.5) | 19(3.8) | 2(2.1) | 2(1.5) | |||
| Ever breastfed more than one month | 0.332 | 0.404 | 0.653 | ||||
| Yes | 677(75.9) | 386(76.0) | 100(78.7) | 95(77.2) | |||
| No | 191(21.4) | 95(18.7) | 23(18.1) | 24(19.5) | |||
| Missing | 24(2.7) | 27(5.3) | 4(3.2) | 4(3.3) | |||
| BMI kg/m2 | 0.096 | 0.808 | 0.272 | ||||
| < 25 | 240(26.9) | 154(30.3) | 35(27.6) | 31(25.2) | |||
| 25–29.99 | 305(34.2) | 171(33.7) | 38(29.9) | 45(36.6) | |||
| ≥ 30 | 324(36.3) | 153(30.1) | 45(35.4) | 44(35.8) | |||
| Missing | 23(2.6) | 30(5.9) | 9(7.1) | 2(2.4) | |||
| WHR | 0.004 | 0.095 | 0.565 | ||||
| High, > 0.85 | 558(62.6) | 347(68.4) | 86(67.7) | 80(65.0) | |||
| Normal≤ 0.85 | 299(33.5) | 130(25.5) | 32(25.2) | 38(30.9) | |||
| Missing | 35(3.9) | 31(6.1) | 9(7.1) | 5(4.1) | |||
| Smoke | 0.714 | 0.972 | 0.334 | ||||
| Yes | 7(0.8) | 3(0.6) | 1(0.7) | 0(0) | |||
| No | 879(98.5) | 485(95.5) | 121(95.3) | 121(98.4) | |||
| Missing | 6(0.7) | 20(3.9) | 5(4.0) | 2(1.6) | |||
| Alcohol use | 0.507 | 0.107 | 0.037 | ||||
| Yes | 178(20.0) | 105(20.7) | 17(13.3) | 35(28.5) | |||
| No | 708(79.4) | 381(75.0) | 105(82.7) | 86(69.9) | |||
| Missing | 6(0.6) | 22(4.3) | 5(4,0) | 2(1.6) | |||
| Total METs hour/week | 11.9 ± 14.9 | 8.3 ± 11.1 | < 0.001 | 10.6 ± 16.3 | 0.369 | 7.8 ± 9.4 | 0.003 |
| Physical activity at home (Standing hour/week) | 0.051 | 0.025 | 0.093 | ||||
| 0–5 | 291(32.6) | 191(37.6) | 30(23.6) | 48(39.0) | |||
| 6–10 | 323(36.2) | 164(32.3) | 40(31.6) | 47(38.2) | |||
| ≥ 10 | 273(30.6) | 131(25.8) | 52(40.9) | 26(21.2) | |||
| Missing | 5(0.6) | 22(4.3) | 5(3.9) | 2(1.6) | |||
| Physical activity at work (Standing hour/week) | < 0.001 | 0.208 | 0.007 | ||||
| 0–5 | 185(20.7) | 156(30.7) | 34(28.8) | 40(32.5) | |||
| 6–10 | 276(30.9) | 158(31.1) | 33(26.0) | 36(29.3) | |||
| ≥ 10 | 426(47.8) | 173(34.1) | 55(43.3) | 45(36.6) | |||
| Missing | 5(0.6) | 21(4.1) | 5(3.9) | 2(1.6) | |||
| Leisure-time physical activity (meet the WHO recommendations) | < 0.001 | 0.134 | < 0.001 | ||||
| Physical active | 246(27.7) | 84(16.6) | 28(22.1) | 19(15.4) | |||
| Physical inactive | 616(69.1) | 374(73.6) | 93(73.2) | 97(78.9) | |||
| Missing | 30(3.2) | 50(9.8) | 6(4.7) | 7(5.7) | |||
| Leisure-time physical activity by METs h/w | < 0.001 | 0.032 | < 0.001 | ||||
| < 3.75 | 208(23.3) | 202(39.8) | 48(37.8) | 56(45.5) | |||
| 3.75–6.69 | 222(24.9) | 100(19.7) | 28(22.0) | 26(21.1) | |||
| 6.70–14.74 | 216(24.2) | 80(15.7) | 20(15.8) | 15(12.2) | |||
| 14.75 ≤ | 216(24.2) | 76(15.0) | 25(19.7) | 19(15.5) | |||
| Missing | 30(3.4) | 50(9.8) | 6(4.7) | 7(5.7) | |||
BMI, Body Mass Index; HS, High School; METs, Metabolic Equivalents; SD, Standard Deviation; WHR, Waist-Hip Ratio; h, hour; w, week.
a
cases(Total, hormone receptor positive, triple-negative) are compared to controls.