Table 5 Trends and regression results for age at first sex by selected covariates in KAIS 2007, KAIS 2012 and KENPHIA 2018
| Â | Summary Analysis | Survey weighted Regression | |||||
|---|---|---|---|---|---|---|---|
Variable | N | Mean (95% CI) | Median (Range) | Unadjusted β (95% CI) | p-value | Adjusted β (95% CI) | p-value |
Year of survey | |||||||
 2007 | 5093 | 17.45(17.32–17.58) | 16.9(21) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 2012 | 4144 | 17.74(17.57–17.9) | 17.2(28) | 0.31(0.09–0.52) | 0.0048 | -0.24(-0.62–0.15) | 0.2291 |
 2018 | 8055 | 17.66(17.54–17.78) | 17.2(45) | 0.24(0.06–0.42) | 0.009 | -0.89(-1.68–0.11) | 0.0251 |
Sex | |||||||
 Female | 10,504 | 17.77(17.63–17.91) | 17.2(34) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Male | 6788 | 17.47(17.3–17.64) | 16.9(45) | -0.33(-0.54–0.13) | 0.0014 | -0.96(-1.17–0.75) |  < .0001 |
Age | |||||||
 20–24 | 9097 | 17.44(17.32–17.56) | 17.1(44) | 1.00 (Reference) |  |  |  |
 25–29 | 8195 | 17.86(17.69–18.03) | 17.1(45) | 0.38(0.2–0.56) |  < 0.001 | 0.27(0.19–0.36) |  < .0001 |
Cohort | |||||||
 1975–1979 | 916 | 17.56(17.31–17.82) | 16.9(21) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 1980–1984 | 3197 | 17.6(17.42–17.78) | 16.9(28) | 0.01(-0.29–0.31) | 0.9525 | 0.56(0.14–0.97) | 0.0086 |
 1984–1989 | 4438 | 17.75(17.59–17.91) | 17.2(28) | 0.2(-0.09–0.5) | 0.1811 | 1.25(0.53–1.96) |  < 0.001 |
 1990–1994 | 5366 | 17.47(17.27–17.66) | 17.3(45) | -0.05(-0.38–0.28) | 0.7678 | 1.56(0.56–2.57) | 0.0024 |
 1995–1999 | 3375 | 17.27(17.11–17.42) | 17.1(27) | -0.27(-0.57–0.04) | 0.0836 | 1.68(0.31–3.06) | 0.0165 |
Place of residence | |||||||
 Urban | 7280 | 18.01(17.81–18.22) | 17.4(45) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Rural | 10,012 | 17.38(17.24–17.51) | 16.9(44) | -0.64(-0.9–0.39) |  < 0.001 | 0.05(-0.23–0.34) | 0.7261 |
Level of education | |||||||
 No education | 1307 | 16.31(15.79–16.84) | 15.4(28) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Primary | 7807 | 17.09(16.96–17.22) | 16.5(34) | 0.8(0.27–1.34) | 0.0032 | 0.66(0.17–1.15) | 0.0085 |
 Secondary +  | 8177 | 18.48(18.29–18.66) | 17.9(45) | 2.2(1.65–2.74) |  < 0.001 | 1.68(1.16–2.19) |  < .0001 |
Marital status | |||||||
 Never married | 6924 | 18.32(18.16–18.48) | 17.8(44) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Separated/Divorced/Widowed | 539 | 16.65(16.3–17) | 16(22) | -1.67(-2.04–1.29) |  < 0.001 | -1.78(-2.16–1.39) |  < .0001 |
 Married/Living together | 9212 | 17.2(17.06–17.34) | 16.6(45) | -1.12(-1.31–0.93) |  < 0.001 | -1.38(-1.58–1.18) |  < .0001 |
Wealth index | |||||||
 Poorest | 3311 | 16.98(16.69–17.28) | 16.4(44) | 1.00 (Reference) |  | 1.00 (Reference) |  |
 Poorer | 3011 | 17.2(16.96–17.45) | 16.6(34) | 0.23(-0.13–0.58) | 0.2148 | -0.01(-0.32–0.3) | 0.9562 |
 Middle | 3114 | 17.34(17.13–17.54) | 17(28) | 0.38(0.02–0.74) | 0.039 | 0.07(-0.25–0.4) | 0.668 |
 Richer | 3621 | 17.75(17.54–17.95) | 17.1(45) | 0.79(0.43–1.15) |  < 0.001 | 0.33(0–0.67) | 0.0531 |
 Richest | 4235 | 18.31(18.08–18.55) | 17.8(28) | 1.33(0.95–1.71) |  < 0.001 | 0.51(0.11–0.91) | 0.0134 |