Table 2.
Cox regression analyses of female reproductive health indicators with incident COPD-related hospitalisation/death during follow-up in women without COPD at baseline (n=271 271)
| Reproductive health indicator | % of participants | Person-years of follow-up | Number of COPD events | Age-adjusted | Multiple-adjusted* | ||
| HR | 95% CI | HR | 95% CI | ||||
| Age at menarche | |||||||
| <12 years | 20.0 | 326 027 | 275 | 1.31 | 1.14 to 1.51 | 1.15 | 1.00 to 1.32 |
| 12–15 years | 74.1 | 1 210 146 | 768 | 1.0 | NA | 1.0 | NA |
| >15 years | 5.9 | 95 771 | 95 | 1.61 | 1.29 to 1.99 | 1.37 | 1.11 to 1.71 |
| Menopause status | |||||||
| No | 26.6 | 437 890 | 97 | 1.0 | NA | 1.0 | NA |
| Yes | 73.4 | 1 194 055 | 1041 | 1.47 | 1.12 to 1.94 | 1.07 | 0.82 to 1.41 |
| Age at natural menopause† | |||||||
| <47 years | 20.3 | 202 811 | 270 | 2.21 | 1.83 to 2.68 | 1.44 | 1.19 to 1.75 |
| 47–49 years | 15.8 | 158 718 | 140 | 1.55 | 1.24 to 1.94 | 1.25 | 1.00 to 1.57 |
| 50–52 years | 35.4 | 354 774 | 219 | 1.0 | NA | 1.0 | NA |
| >52 years | 28.4 | 283 721 | 161 | 0.86 | 0.69 to 1.06 | 0.93 | 0.75 to 1.15 |
| Parity, binary | |||||||
| Nulliparous | 15.1 | 244 938 | 116 | 0.77 | 0.63 to 0.93 | 0.92 | 0.76 to 1.12 |
| Parous | 84.9 | 1 387 009 | 1022 | 1.0 | NA | 1.0 | NA |
| Parity, ordered categories | |||||||
| 0 | 15.1 | 244 938 | 116 | 1.0 | NA | 1.0 | NA |
| 1 | 12.2 | 198 124 | 139 | 1.41 | 1.10 to 1.81 | 1.06 | 0.82 to 1.35 |
| 2 | 34.4 | 562 339 | 308 | 0.96 | 0.78 to 1.19 | 0.92 | 0.74 to 1.14 |
| 3 | 25.3 | 413 347 | 293 | 1.24 | 1.00 to 1.54 | 1.06 | 0.85 to 1.33 |
| >3 | 13.1 | 213 195 | 282 | 2.21 | 1.78 to 2.75 | 1.45 | 1.16 to 1.82 |
| PCOS/ovarian cysts | |||||||
| No | 98.3 | 1 604 641 | 1108 | 1.0 | NA | 1.0 | NA |
| Yes | 1.7 | 27 304 | 30 | 1.61 | 1.12 to 2.32 | 1.61 | 1.12 to 2.32 |
| Endometriosis | |||||||
| No | 98.5 | 1 607 817 | 1127 | 1.0 | NA | 1.0 | NA |
| Yes | 1.5 | 24 131 | 11 | 0.79 | 0.44 to 1.43 | 0.85 | 0.47 to 1.53 |
| Oral contraception | |||||||
| Never used | 18.9 | 308 641 | 295 | 1.0 | NA | 1.0 | NA |
| Ever used | 81.1 | 1 323 303 | 843 | 0.95 | 0.83 to 1.09 | 0.85 | 0.74 to 0.97 |
| Years of oral contraception use | |||||||
| 0 | 18.9 | 308 641 | 295 | 1.0 | NA | 1.0 | NA |
| 1 | 11.1 | 180 195 | 137 | 1.05 | 0.85 to 1.29 | 0.84 | 0.69 to 1.04 |
| 2–4 | 18.7 | 306 053 | 246 | 1.05 | 0.88 to 1.24 | 0.95 | 0.80 to 1.13 |
| 5–9 | 17.8 | 290 554 | 181 | 0.92 | 0.76 to 1.11 | 0.86 | 0.71 to 1.05 |
| 10–15 | 17.5 | 285 766 | 153 | 0.84 | 0.69 to 1.03 | 0.74 | 0.61 to 0.91 |
| >15 | 16.1 | 260 734 | 126 | 0.83 | 0.67 to 1.04 | 0.75 | 0.60 to 0.93 |
| HRT | |||||||
| Never used | 63.9 | 1 042 083 | 510 | 1.0 | NA | 1.0 | NA |
| Ever used | 36.1 | 589 861 | 628 | 1.49 | 1.31 to 1.69 | 1.15 | 1.01 to 1.30 |
| Years of HRT | |||||||
| 0 | 63.9 | 1 042 083 | 510 | 1.0 | NA | 1.0 | NA |
| 1–2 | 11.7 | 190 902 | 240 | 1.83 | 1.54 to 2.16 | 1.33 | 1.12 to 1.57 |
| 3–5 | 9.1 | 147 962 | 162 | 1.63 | 1.34 to 1.97 | 1.17 | 0.97 to 1.42 |
| 6–10 | 6.2 | 100 921 | 74 | 1.0 | 0.77 to 1.31 | 0.87 | 0.66 to 1.14 |
| >10 | 9.2 | 150 077 | 152 | 1.27 | 1.04 to 1.55 | 1.06 | 0.87 to 1.29 |
| Gynaecological surgery | |||||||
| No | 81.8 | 1 335 512 | 765 | 1.0 | NA | 1.0 | NA |
| Hysterectomy | 10.1 | 164 869 | 213 | 1.77 | 1.51 to 2.07 | 1.49 | 1.28 to 1.74 |
| Bilateral oophorectomy | 0.4 | 5957 | 6 | 1.56 | 0.70 to 3.48 | 1.36 | 0.61 to 3.04 |
| Both | 7.8 | 125 607 | 154 | 1.68 | 1.41 to 2.00 | 1.42 | 1.19 to 1.69 |
*Multiple-adjusted for age, height, body mass index (log-transformed), ethnicity, education, household income, Townsend deprivation index, smoking history, maternal COPD and paternal COPD.
†Age at menopause was analysed only among women who experienced natural menopause before baseline (n=159 571).
COPD, chronic obstructive pulmonary disease; HRT, hormone replacement therapy; PCOS, polycystic ovary syndrome.