Table 6 Person-time analysis and survey-weighted Cox-regression of age at sexual debut by selected covariates in KAIS 2007, KAIS 2012 and KENPHIA 2018
Variable | Person-time analysis | Survey-weighted Cox-regression | |||||
|---|---|---|---|---|---|---|---|
| Â | Event | Person-time | Rate (95% CI) | HR (95% CI) | p-value | AHR (95% CI) | p-value |
Year | |||||||
 2007 | 1080 | 92,901 | 11.63(10.95–12.34) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 2012 | 793 | 75,892 | 10.45(9.75–11.2) | 0.97(0.86–1.09) | 0.5837 | 1.01(0.85–1.19) | 0.9431 |
 2018 | 1376 | 143,682 | 9.58(9.08–10.1) | 0.8(0.71–0.89) |  < 0.001 | 0.87(0.63–1.18) | 0.3629 |
Cohort | |||||||
 1975–1979 | 189 | 16,789 | 11.26(9.76–12.98) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 1980–1984 | 737 | 59,137 | 12.46(11.59–13.4) | 1.22(0.99–1.5) | 0.0574 | 1.27(1.01–1.59) | 0.0408 |
 1984–1989 | 824 | 80,902 | 10.19(9.51–10.9) | 1.01(0.83–1.23) | 0.8936 | 1.12(0.85–1.48) | 0.4113 |
 1990–1994 | 922 | 96,884 | 9.52(8.92–10.15) | 0.88(0.69–1.11) | 0.2693 | 1.07(0.73–1.55) | 0.7431 |
 1995–1999 | 577 | 58,763 | 9.82(9.05–10.65) | 0.87(0.71–1.07) | 0.1979 | 1.32(0.81–2.15) | 0.2625 |
Age | |||||||
 20–24 | 1638 | 161,535 | 10.14(9.66–10.64) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 25–29 | 1611 | 150,940 | 10.67(10.16–11.21) | 1.17(1.05–1.31) | 0.0047 | 0.96(0.81–1.13) | 0.6292 |
Sex | |||||||
 Male | 1425 | 119,908 | 11.88(11.28–12.52) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Female | 1824 | 192,567 | 9.47(9.05–9.92) | 1.05(0.92–1.2) | 0.5055 | 0.76(0.67–0.86) |  < .0001 |
Residence | |||||||
 Urban | 1170 | 133,603 | 8.76(8.27–9.27) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Rural | 2079 | 178,872 | 11.62(11.13–12.13) | 1.31(1.13–1.5) |  < 0.001 | 0.99(0.81–1.21) | 0.8922 |
Education | |||||||
 No education | 472 | 23,989 | 19.68(17.98–21.53) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Primary | 1720 | 136,383 | 12.61(12.03–13.22) | 0.45(0.37–0.54) |  < 0.001 | 0.47(0.4–0.56) |  < .0001 |
 Secondary +  | 1057 | 152,085 | 6.95(6.54–7.38) | 0.27(0.21–0.33) |  < 0.001 | 0.32(0.26–0.4) |  < .0001 |
Marital status | |||||||
 Never married | 977 | 127,821 | 7.64(7.18–8.14) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Married/Living together | 128 | 9459 | 13.53(11.38–16.09) | 1.72(1.49–1.98) |  < 0.001 | 1.57(1.37–1.8) |  < .0001 |
 Separated/Divorced/Widowed | 2018 | 164,493 | 12.27(11.74–12.82) | 1.94(1.5–2.49) |  < 0.001 | 1.78(1.37–2.32) |  < .0001 |
Wealth | |||||||
 Poorest | 908 | 58,409 | 15.55(14.57–16.59) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Poorer | 620 | 52,995 | 11.7(10.81–12.66) | 0.76(0.62–0.94) | 0.0115 | 0.91(0.76–1.08) | 0.2772 |
 Middle | 598 | 55,856 | 10.71(9.88–11.6) | 0.8(0.65–0.99) | 0.0441 | 1.01(0.84–1.22) | 0.919 |
 Richer | 566 | 65,946 | 8.58(7.9–9.32) | 0.57(0.46–0.71) |  < 0.001 | 0.75(0.61–0.93) | 0.009 |
 Richest | 557 | 79,269 | 7.03(6.47–7.64) | 0.55(0.44–0.68) |  < 0.001 | 0.82(0.63–1.06) | 0.1309 |