Table 2 Adjusted associations of socioeconomic, reproductive and lifestyle factors with age at natural menopause (n = 6138)
Age at natural menopause (ANM) (years) | |||||
|---|---|---|---|---|---|
<45 RRR (95% CI) | 45–49 RRR (95% CI) | 50–51 RRR (95% CI) | 52–53 RRR (95% CI) | ≥54 RRR (95% CI) | |
Education level | |||||
No formal qualifications | 1.72 (1.11–2.65) | 1.36 (1.03–1.81) | Reference | 0.95 (0.71–1.26) | 0.71 (0.54–0.92) |
Less than high school/high school | 1.54 (1.08–2.20) | 0.96 (0.77–1.20) | Reference | 0.84 (0.67–1.04) | 0.71 (0.58–0.86) |
Trade/certificate/diploma | 1.34 (0.90–2.01) | 0.95 (0.74–1.23) | Reference | 0.88 (0.69–1.13) | 0.76 (0.60–0.95) |
University or higher | Reference | Reference | Reference | Reference | Reference |
Difficulty on income management | |||||
Easy/not bad/some difficult | Reference | Reference | Reference | Reference | Reference |
Difficult/impossible | 1.47 (1.08–2.02) | 1.14 (0.89–1.45) | Reference | 0.91 (0.71–1.18) | 1.10 (0.88–1.38) |
Age at menarche (years) | |||||
≤ 11 | 1.54 (1.10–2.16) | 1.30 (1.03–1.64) | Reference | 1.09 (0.86–1.37) | 1.00 (0.80–1.24) |
12 | 1.49 (1.10–2.03) | 0.95 (0.76–1.18) | Reference | 0.88 (0.71–1.09) | 0.92 (0.76–1.13) |
13 | Reference | Reference | Reference | Reference | Reference |
14 | 1.14 (0.80–1.62) | 1.13 (0.90–1.43) | Reference | 0.94 (0.74–1.18) | 1.09 (0.88–1.35) |
≥ 15 | 1.34 (0.94–1.91) | 1.09 (0.86–1.39) | Reference | 0.98 (0.77–1.25) | 1.18 (0.95–1.46) |
Number of children | |||||
0 | 1.28 (0.87–1.89) | 1.32 (1.00–1.73) | Reference | 1.00 (0.76–1.34) | 0.83 (0.63–1.08) |
1 | 1.04 (0.71–1.52) | 1.16 (0.89–1.51) | Reference | 0.86 (0.65–1.14) | 0.86 (0.66–1.11) |
2–3 | Reference | Reference | Reference | Reference | Reference |
≥ 4 | 0.99 (0.73–1.35) | 0.97 (0.78–1.20) | Reference | 1.04 (0.84–1.29) | 0.94 (0.77–1.15) |
Body mass index (kg/m2) | |||||
Underweight (<18.5) | 1.27 (0.57–2.83) | 1.36 (0.77–2.40) | Reference | 1.18 (0.65–2.14) | 0.92 (0.51–1.65) |
Normal weight (18.5–24.9) | Reference | Reference | Reference | Reference | Reference |
Overweight (25–29.9) | 1.10 (0.85–1.42) | 1.06 (0.89–1.27) | Reference | 1.12 (0.94–1.34) | 1.34 (1.14–1.58) |
Obese (≥30) | 1.03 (0.75–1.41) | 1.08 (0.87–1.34) | Reference | 1.10 (0.88–1.37) | 1.26 (1.03–1.55) |
Perceived stress | |||||
No (stress scores <1) | Reference | Reference | Reference | Reference | Reference |
Yes (stress scores ≥1) | 1.15 (0.88–1.50) | 1.12 (0.93–1.36) | Reference | 0.94 (0.77–1.14) | 1.00 (0.83–1.19) |
Smoking status | |||||
Never | Reference | Reference | Reference | Reference | Reference |
Ex-smoker | 1.21 (0.93–1.57) | 0.88 (0.74–1.05) | Reference | 0.90 (0.76–1.07) | 0.93 (0.80–1.09) |
Current smoker, <10 cigarettes/day | 1.69 (0.98–2.92) | 0.84 (0.54–1.30) | Reference | 0.86 (0.56–1.32) | 0.73 (0.49–1.10) |
Current smoker, 10–19 cigarettes/day | 2.00 (1.22–3.27) | 1.13 (0.77–1.67) | Reference | 0.80 (0.53–1.23) | 0.69 (0.46–1.03) |
Current smoker, ≥20 cigarettes/day | 2.98 (2.11–4.20) | 1.71 (1.30–2.25) | Reference | 0.82 (0.59–1.12) | 0.81 (0.61–1.09) |