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Table 2 Adjusted hazard ratios (95% confidence intervals) for incident coronary heart disease, stroke, and circulatory disease associated with number of pregnancies, miscarriages, induced abortions, and stillbirths

From: Pregnancy, pregnancy loss, and the risk of cardiovascular disease in Chinese women: findings from the China Kadoorie Biobank

  CHD Stroke Circulatory disease
No. events HR (95% CI) No. events HR (95% CI) No. events HR (95% CI)
Pregnancies
Ever vs. never   0.91 (0.78; 1.06)   0.98 (0.86; 1.12)   0.98 (0.89; 1.07)
 None 166 1.20 (1.03; 1.40) 211 1.06 (0.93; 1.22) 429 1.14 (1.04; 1.26)
 1 779 1.00 (0.93; 1.08) 994 1.00 (0.94; 1.07) 2333 1.00 (0.96; 1.04)
 2 2534 1.01 (0.96; 1.05) 3501 0.99 (0.95; 1.02) 8915 1.07 (1.04; 1.09)
 3 3306 1.03 (1.00; 1.07) 4718 1.02 (0.99; 1.05) 11,193 1.10 (1.08; 1.12)
 4 3021 1.14 (1.10; 1.18) 4064 1.03 (1.00; 1.06) 8804 1.13 (1.11; 1.15)
  ≥ 5 4634 1.19 (1.15; 1.24) 6437 1.09 (1.05; 1.13) 12,294 1.19 (1.16; 1.22)
Per additional a   1.04 (1.03; 1.05)   1.02 (1.02; 1.03)   1.03 (1.02; 1.04)
Miscarriages
Ever vs. never b   1.07 (1.02; 1.13)   1.04 (1.00; 1.09)   1.04 (1.01; 1.07)
None 12,629 1.00 (0.98; 1.02) 17,497 1.00 (0.98; 1.02) 39,089 1.00 (0.99; 1.01)
 1 1220 1.04 (0.98; 1.10) 1695 1.04 (0.99; 1.09) 3390 1.01 (0.98; 1.05)
 2 304 1.19 (1.06; 1.33) 374 1.09 (0.99; 1.21) 779 1.12 (1.05; 1.21)
  ≥ 3 121 1.26 (1.05; 1.51) 148 1.15 (0.98; 1.36) 281 1.12 (0.99; 1.26)
Per additional a   1.07 (1.01; 1.14)   1.04 (0.98; 1.10)   1.04 (1.00; 1.09)
Induced abortions
Ever vs. never b   1.11 (1.06; 1.15)   1.04 (1.01; 1.07)   1.04 (1.02; 1.07)
 None 7334 1.00 (0.97; 1.03) 10,071 1.00 (0.98; 1.02) 22,775 1.00 (0.98; 1.02)
 1 3714 1.08 (1.05; 1.11) 5217 1.04 (1.01; 1.06) 11,834 1.04 (1.02; 1.06)
 2 2160 1.13 (1.08; 1.18) 2904 1.05 (1.01; 1.09) 6032 1.05 (1.02; 1.07)
  ≥ 3 1066 1.14 (1.07; 1.21) 1522 1.09 (1.04; 1.15) 2898 1.09 (1.05; 1.13)
Per additional a   1.02 (1.00; 1.05)   1.03 (1.00; 1.05)   1.02 (1.01; 1.04)
Stillbirths
Ever vs. never b   1.00 (0.94; 1.07)   1.06 (1.01; 1.12)   1.07 (1.03; 1.11)
 None 13,078 1.00 (0.96; 1.04) 17,846 1.00 (0.97; 1.03) 40,052 1.00 (0.98; 1.02)
 1 822 0.96 (0.90; 1.02) 1355 1.05 (1.00; 1.11) 2538 1.05 (1.01; 1.09)
 2 240 1.08 (0.95; 1.23) 368 1.13 (1.02; 1.25) 662 1.12 (1.04; 1.21)
  ≥ 3 134 1.31 (1.10; 1.56) 145 0.99 (0.84; 1.17) 287 1.13 (1.01; 1.28)
Per additional a   1.13 (1.06; 1.20)   1.02 (0.96; 1.08)   1.04 (1.00; 1.08)
  1. HRs are stratified by age and study area, and adjusted for level of attained education, household income, smoking status, alcohol use, systolic blood pressure, history of hypertension, physical activity, body mass index, and history of diabetes. Analyses for miscarriage, induced abortion, and stillbirth were additionally adjusted for number of live births, and where appropriate, number of miscarriages, induced abortions, and stillbirths. aAnalyses are restricted to women with at least one pregnancy, miscarriage, induced abortion, or stillbirth, respectively. bAnalyses are restricted to women with at least one pregnancy