Table 2

Adjusted OR's—infertility and earlier age at menopause (<50 years) by smoking status

Tobacco exposureInfertility, n (%)Age at menopause, n (%)
NoYesOR (95% CI)<50≥50OR (95% CI)
Smoking status
 Never-smoker, SHS none3076 (4.7)506 (4.3)1.0 (Ref)1301 (4.2)1935 (5.1)1.0 (Ref)
 Never-smoker, SHS29 838 (46.0)5347 (45.0)1.08 (0.98 to 1.19)13 573 (44.0)18 003 (47.0)1.07 (0.99 to 1.15)
 Ever smokers31 980 (49.3)6019 (50.7)1.14 (1.03 to 1.26)15 977 (51.8)18 394 (48.0)1.27 (1.18 to 1.37)
Age started smoking (years)
 Never-smoker, SHS none3076 (4.7)506 (4.3)1.0 (Ref)1301 (4.2)1935 (5.0)1.0 (Ref)
 Never-smoker, SHS29 838 (45.8)5347 (44.9)1.08 (0.98 to 1.20)13 573 (43.9)18 003 (46.9)1.07 (0.99 to 1.15)
 <152035 (3.1)391 (3.3)1.18 (1.02 to 1.36)1138 (3.7)1037 (2.7)1.42 (1.27 to 1.59)
 15–1916 153 (24.8)3049 (25.6)1.14 (1.03 to 1.27)8100 (26.2)9309 (24.2)1.27 (1.17 to 1.37)
 20–2410 040 (15.4)1975 (16.6)1.19 (1.07 to 1.32)4914 (15.9)5981 (15.6)1.24 (1.14 to 1.35)
 25–292136 (3.3)378 (3.2)1.10 (0.95 to 1.27)1043 (3.4)1192 (3.1)1.27 (1.13 to 1.42)
 ≥301819 (2.8)256 (2.2)0.86 (0.73 to 1.01)878 (2.8)964 (2.5)1.31 (1.16 to 1.47)
 p Value for trend0.124<0.001
Average cigarettes/day
 Never-smoker, SHS none3076 (4.8)506 (4.3)1.0 (Ref)1301 (4.3)1935 (5.1)1.0 (Ref)
 Never-smoker, SHS29 838 (46.7)5347 (45.9)1.08 (0.98 to 1.20)13 573 (44.7)18 003 (47.7)1.07 (0.99 to 1.16)
 <57241 (11.3)1240 (10.6)1.04 (0.93 to 1.17)3282 (10.8)4357 (11.6)1.11 (1.01 to 1.20)
 5–149821 (15.4)1836 (15.7)1.14 (1.02 to 1.27)4751 (15.7)5780 (15.3)1.21 (1.11 to 1.31)
 15–248474 (13.3)1647 (14.1)1.17 (1.05 to 1.31)4413 (14.5)4770 (12.7)1.37 (1.26 to 1.49)
 ≥255413 (8.5)1085 (9.3)1.21 (1.08 to 1.36)3022 (10.0)2865 (7.6)1.53 (1.40 to 1.67)
 p Value for trend<0.001<0.001
Years smoked before menopause
 Never-smoker, SHS none3076 (5.0)506 (4.5)1.0 (Ref)1301 (4.37)1935 (5.2)1.0 (Ref)
 Never-smoker, SHS29 838 (48.3)5347 (47.0)1.08 (0.98 to 1.19)13 573 (45.6)18 003 (48.4)1.06 (0.99 to 1.15)
 <51688 (2.7)304 (2.7)1.08 (0.93 to 1.26)824 (2.8)995 (2.7)1.17 (1.04 to 1.31)
 5–93463 (5.6)632 (5.6)1.09 (0.96 to 1.24)1742 (5.9)2046 (5.5)1.22 (1.11 to 1.35)
 10–198034 (13.0)1718 (15.1)1.29 (1.16 to 1.44)4617 (15.5)4348 (11.7)1.54 (1.42 to 1.68)
 20–299710 (15.7)1833 (16.1)1.15 (1.03 to 1.28)6185 (20.8)4593 (12.3)1.97 (1.81 to 2.14)
 30+5976 (9.7)1033 (9.1)1.05 (0.94 to 1.18)1509 (5.1)5314 (14.3)0.41 (0.37 to 0.45)
 p Value for trend0.0070.220
Pack-years before menopause
 Never-smoker, SHS none3076 (5.1)506 (4.5)1301 (4.5)1935 (5.3)1.0 (Ref)
 Never-smoker, SHS29 838 (49.2)5347 (47.9)1.08 (0.98 to 1.19)13 573 (46.5)18 003 (49.2)1.07 (0.99 to 1.15)
 <1011 343 (18.7)2121 (19.0)1.13 (1.02 to 1.26)5677 (19.4)6796 (18.6)1.22 (1.12 to 1.32)
 10 to <206693 (11.0)1324 (11.9)1.20 (1.07 to 1.35)3524 (12.1)3992 (10.9)1.29 (1.19 to 1.41)
 20 to <303680 (6.1)767 (6.9)1.26 (1.12 to 1.43)2427 (8.3)1702 (4.7)2.11 (1.92 to 2.32)
 30 to <403116 (5.1)554 (5.0)1.08 (0.94 to 1.23)1256 (4.3)2232 (6.1)0.82 (0.74 to 0.90)
 40+2958 (4.9)549 (4.9)1.12 (0.98 to 1.28)1453 (5.0)1912 (5.2)1.10 (0.99 to 1.21)
 p Value for trend0.005<0.001
  • Adjusted for age decades, race, education, alcohol use, insecticide exposure, OC use, BMI at 18 years, and hard exercise at 18 years.

  • Models for age at menopause are also adjusted for age at menarche.

  • BMI, body mass index; OC, oral contraceptive; SHS, secondhand smoke.