From: Factors associated with menstrual cycle irregularity and menopause
Variables | Early menopause (< 50 years) | Late menopause (≥50 years) | Logistic regression for early menopause (< 50 years)a | Linear regression for menopausal age (categorical variable)a | Linear regression for menopausal age (continuous variable)a | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
n | % | n | % | OR | 95% CI | β | SE | p-value | β | SE | p-value | ||
(mean) | (SD) | (mean) | (SD) | ||||||||||
Total | 4930 | 45.9 | 5767 | 54.1 | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Current age, mean (SD) | 64.5 | 0.2 | 62.8 | 0.2 | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Average menopausal age, mean (SD) | 45.6 | 0.1 | 52.5 | 0.0 | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Smoking status | |||||||||||||
 Non-smoker | 4447 | 90.6 | 5343 | 93.6 | 1.00 |  |  | 1.000 |  |  |  |  |  |
 Ex-smoker | 172 | 3.7 | 160 | 2.9 | 1.34 | 1.02 | 1.77 | −0.615 | 0.365 | 0.093 |  |  |  |
 Current smoker | 236 | 5.7 | 175 | 3.5 | 1.68 | 1.30 | 2.17 | −1.137 | 0.283 | <.0001 |  |  |  |
 Total | 4855 | 100.0 | 5678 | 100.0 |  |  |  |  |  |  |  |  |  |
Cigarettes per day | |||||||||||||
 Non-smoker | 4447 | 92.3 | 5343 | 95.1 | 1.00 |  |  | 1.000 |  |  |  |  |  |
 < 20 cigarettes | 268 | 6.1 | 205 | 3.9 | 1.61 | 1.26 | 2.07 | −1.104 | 0.302 | 0.000 |  |  |  |
 ≥ 20 cigarettes | 69 | 1.5 | 55 | 1.0 | 1.53 | 1.00 | 2.33 | −0.486 | 0.444 | 0.274 |  |  |  |
 Total | 4784 | 100.0 | 5603 | 100.0 |  |  |  |  |  |  | −0.038 | 0.019 | 0.046 |
Age at smoking initiationb | |||||||||||||
 Non-smoker | 3409 | 89.9 | 3993 | 93.1 | 1.00 |  |  | 1.000 |  |  |  |  |  |
 < 20 years | 36 | 1.2 | 15 | 0.4 | 2.93 | 1.45 | 5.90 | −1.438 | 0.461 | 0.002 |  |  |  |
 ≥ 20 years | 298 | 8.9 | 246 | 6.4 | 1.43 | 1.13 | 1.82 | −0.827 | 0.293 | 0.005 |  |  |  |
 Total | 3743 | 100.0 | 4254 | 100.0 |  |  |  |  |  |  | −0.004 | 0.001 | <.0001 |
Pack-year (total)b | |||||||||||||
 Non-smoker | 3409 | 90.2 | 3993 | 93.4 | 1.00 |  |  |  |  |  |  |  |  |
 Below or equal to the median (≤9.8 pack-years) | 153 | 4.9 | 175 | 3.4 | 1.50 | 1.11 | 2.01 | −0.773 | 0.342 | 0.024 |  |  |  |
 Above the median (>9.8 pack-years) | 172 | 4.9 | 78 | 3.3 | 1.57 | 1.17 | 2.09 | −1.037 | 0.389 | 0.008 |  |  |  |
 Total | 3734 | 100.0 | 4246 | 100.0 |  |  |  |  |  |  | −0.025 | 0.015 | 0.103 |
Pack-year (before menopause)b | |||||||||||||
 Non-smoker | 3409 | 92.0 | 3993 | 93.7 | 1.00 |  |  | 1.000 |  |  |  |  |  |
 Below or equal to the median (≤5 pack-years) | 133 | 4.0 | 107 | 2.7 | 1.54 | 1.11 | 2.13 | −1.076 | 0.370 | 0.004 |  |  |  |
 Above the median (>5 pack-years) | 123 | 4.0 | 131 | 3.6 | 1.14 | 0.83 | 1.57 | 0.417 | 0.340 | 0.220 |  |  |  |
 Total | 3665 | 100.0 | 4231 | 100.0 |  |  |  |  |  |  | 0.035 | 0.020 | 0.077 |