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. 2019 Apr 5;12(6):819–827. doi: 10.1016/j.tranon.2019.03.001

Table 2-2.

Menstrual and Reproductive Factors in Association with the Risk of Lung Cancer, by Smoking Status

Never Smokers
 Ever Smokers
Cases, n = 499
 Ctrls, n = 1464
 Adjusted OR2
 SB-adjusted OR2
 Cases, n = 181
 Ctrls, n = 344
 Adjusted OR3
 SB-adjusted OR3
N % N % (95% CI) (95% PI) N % N % (95% CI) (95% PI)
Menstrual Characteristics
Age at menarche
 <=15 175 35.57 553 37.93 1.00(Ref) 1.00(Ref) 49 27.22 86 25.37 1.00(Ref) 1.00(Ref)
 16–17 187 38.01 534 36.63 1.25 (0.96, 1.64) 1.26 (0.98, 1.63) 75 41.67 155 45.72 0.94 (0.57, 1.53) 0.94 (0.60, 1.48)
 > = 18 130 26.42 371 25.45 1.34 (0.99, 1.82) 1.35 (1.01, 1.80) 56 31.11 98 28.91 1.01 (0.59, 1.74) 1.02 (0.62, 1.67)
 Ptrend4 0.050 0.03 0.962 0.953
 As a continuous variable8 1.04 (0.98, 1.11) 1.05 (0.99, 1.11) 1.05 (0.94, 1.17) 1.05 (0.94, 1.17)
Age at menopause5
 <46 48 10.39 147 10.71 1.00 (Ref) 1.00 (Ref) 14 8.33 42 12.65 1.00 (Ref) 1.00 (Ref)
 46–54 319 69.05 1041 75.82 0.90 (0.61, 1.33) 0.91 (0.64, 1.30) 132 78.57 266 80.12 1.48 (0.72, 3.06) 1.23 (0.68, 2.21)
 >54 95 20.56 185 13.47 1.45 (0.91, 2.29) 1.45 (0.95, 2.20) 22 13.1 24 7.23 2.48 (0.94, 6.51) 1.80 (0.85, 3.84)
 Ptrend 0.035 0.023 0.066 0.077
 As a continuous variable8 1.03 (1.00-, 1.06) 1.03 (1.00+, 1.06) 1.04 (0.98, 1.10) 1.04 (0.98, 1.10)
Reproductive window
 <=32 151 32.54 503 36.53 1.00 (Ref) 1.00 (Ref) 76 44.71 148 44.71 1.00 (Ref) 1.00 (Ref)
 33–35 134 28.88 409 29.70 1.00 (0.75, 1.35) 1.03 (0.78, 1.37) 47 27.65 102 30.82 0.79 (0.48, 1.30) 0.82 (0.51, 1.31)
 > = 36 179 38.58 465 33.77 1.13 (0.86, 1.50) 1.16 (0.89, 1.51) 47 27.65 81 24.47 0.95 (0.57, 1.59) 0.97 (0.60, 1.57)
 Ptrend 0.375 0.274 0.749 0.778
 As a continuous variable8 1.01 (0.98, 1.04) 1.01 (0.99, 1.04) 1.01 (0.96, 1.06) 1.01 (0.96, 1.06)
Reproductive History
Parity6
 0 or 1 80 16.06 176 12.02 1.00 (Ref) 1.00 (Ref) 36 19.89 41 11.92 1.00 (Ref) 1.00 (Ref)
 2–3 242 48.59 753 51.43 0.69 (0.49, 0.97) 0.73 (0.53, 1.00+) 63 34.81 111 32.27 0.67 (0.35, 1.27) 0.76 (0.43, 1.35)
 4 or more 176 35.34 535 36.54 0.74 (0.52, 1.08) 0.84 (0.60, 1.18) 82 45.30 192 55.81 0.52 (0.28, 0.97) 0.60 (0.35, 1.03)
 Ptrend 0.332 0.62 0.114 0.116
 As a continuous variable8 0.95 (0.88, 1.03) 0.97 (0.90, 1.04) 0.91 (0.81, 1.01) 0.91 (0.81, 1.01)
Gravidity6
 0 or 1 71 14.26 159 10.86 1.00 (Ref) 1.00 (Ref) 33 18.23 36 10.47 1.00 (Ref) 1.00 (Ref)
 2–3 222 44.58 677 46.24 0.73 (0.51, 1.05) 0.77 (0.55, 1.07) 53 29.28 96 27.91 0.57 (0.29, 1.12) 0.67 (0.37, 1.21)
 4 or more 205 41.16 628 42.90 0.82 (0.57, 1.20) 0.92 (0.65, 1.30) 95 52.49 212 61.63 0.54 (0.29, 1.00+) 0.62 (0.36, 1.08)
 Ptrend 0.684 0.902 0.268 0.263
 As continuous variable8 0.98 (0.91, 1.05) 1.00 (0.93, 1.07) 0.89 (0.81, 0.99) 0.89 (0.81, 0.99)
Number of live birth6
 0 or 1 82 16.47 183 12.50 1.00 (Ref) 1.00 (Ref) 36 19.89 43 12.5 1.00 (Ref) 1.00 (Ref)
 2–3 249 50 770 52.60 0.69 (0.49, 0.98) 0.74 (0.54, 1.01) 64 35.36 117 34.01 0.67 (0.36, 1.27) 0.76 (0.43, 1.33)
 4 or more 167 33.53 511 34.90 0.75 (0.52, 1.09) 0.84 (0.60, 1.18) 81 44.75 184 53.49 0.56 (0.31, 1.04) 0.64 (0.37, 1.09)
 Ptrend 0.339 0.58 0.206 0.205
 As a continuous variable8 0.94 (0.87, 1.02) 0.94 (0.87, 1.02) 0.92 (0.82, 1.03) 0.92 (0.82, 1.03)
Life time abortion
 Never 463 92.97 1351 92.28 1.00 (Ref) 1.00 (Ref) 168 92.82 299 86.92 1.00 (Ref) 1.00 (Ref)
 Ever 35 7.03 113 7.72 1.29 (0.81, 2.06) 1.23 (0.81, 1.87) 13 7.18 45 13.08 0.62 (0.31, 1.25) 0.66 (0.36, 1.22)
 As a continuous variable8 0.66 (0.38, 1.16) 1.20 (0.92, 1.56) 0.66 (0.38, 1.16) 0.68 (0.41, 1.13)
Outcome of first pregnancy7
 Live birth 460 94.65 1361 94.91 1.00 (Ref) 1.00 (Ref) 171 95.53 295 90.21 1.00 (Ref) 1.00 (Ref)
 Stillbirth 15 3.09 36 2.51 1.05 (0.51, 2.15) 1.15 (0.62, 2.12) 4 2.23 15 4.59 0.43 (0.11, 1.61) 0.64 (0.26, 1.60)
 Miscarriage 11 2.26 1 0.07 1.68 (0.76, 3.69) 1.59 (0.81, 3.11) 3 1.68 17 5.20 0.27 (0.07, 1.01) 0.49 (0.20, 1.19)
 Ectopic Preg 0 0 29 2.02 NA NA 1 0.56 0 0 NA NA
 Induced abortion 0 0 6 0.42 NA NA 0 0 0 0 NA NA
Number of Ovulatory Cycles
 <=366 124 27.93 413 31.97 1.00 (Ref) 1.00 (Ref) 58 36.48 123 40.46 1.00 (Ref) 1.00 (Ref)
 367–413 139 31.31 432 33.44 0.99 (0.73, 1.34) 0.97 (0.73, 1.30) 53 33.33 105 34.54 0.91 (0.55, 1.52) 0.92 (0.57, 1.47)
 > = 414 181 40.77 447 34.60 1.18 (0.88, 1.59) 1.22 (0.92, 1.61) 48 30.19 76 25 1.16 (0.68, 2.00) 1.15 (0.70, 1.89)
 Ptrend 0.233 0.135 0.63 0.632
 As a continuous variable (per 13 ovulatory cycles) 8 1.02 (0.99, 1.04) 1.02 (1.00-, 1.04) 1.02 (0.98, 1.06) 1.02 (0.98, 1.07)
Exogenous Hormone
Oral Contraceptive use
 Never 465 96.47 1327 95.06 1.00 (Ref) 1.00 (Ref) 170 96.59 312 93.13 1.00 (Ref) 1.00 (Ref)
 Ever 17 3.53 69 4.94 1.16 (0.63, 2.14) 1.11 (0.64, 1.93) 6 3.41 23 6.87 0.58 (0.22, 1.54) 0.69 (0.32, 1.49)

Notation:

1. Odds ratios and 95% confidence intervals adjusted for age (as a continuous variable), smoking status (ever or never), pack-years of smoking, family history of lung cancer (yes or no), income, education, county of residence, and BMI.

2. Odds ratios and 95% confidence intervals adjusted for age (as a continuous variable), family history of lung cancer (yes or no), income, education, county of residence, and BMI.

3. Odds ratios and 95% confidence intervals adjusted for age (as a continuous variable), pack-years of smoking, family history of lung cancer (yes or no), income, education, county of residence, and BMI.

4. Mantel trend test.

5. Additional adjustment for age at menarche (as a continuous variable).

6. Additional adjustment for length of reproductive window.

7. Additional adjustment for age at first birth.

8. Absolute number/count as the continuous variable.