Table 3. Summary RE and 95% CI for the association between HRT and the risk of lung cancer.
| Pooled studies | No. of included studies | RE and 95% CI | I2 (%) | Model | P for test |
|---|---|---|---|---|---|
| Study design | 22 | ||||
| Cohort studies | 13 | ||||
| Ever HRT vs. never HRT | 9 | ||||
| Among all participants | 9 | 0.96 (0.90–1.03)a | 23.9 | Fixed-effects model | 0.23 |
| Among female non-smokers | 8 | 0.99 (0.85–1.15)a | 0 | Fixed-effects model | 0.88 |
| Among participants ≥50 years old | 3 | 0.92 (0.85-1.00)a | 0 | Fixed-effects model | 0.04* |
| Current HRT vs. never HRT | 7 | ||||
| Among all participants | 7 | 0.91 (0.86–0.97)a | 22.9 | Fixed-effects model | <0.01** |
| Among postmenopausal women | 4 | 0.91 (0.85–0.98)a | 36 | Fixed-effects model | 0.02* |
| Among participants ≥50 years old | 5 | 0.90 (0.84-0.95)a | 34.1 | Fixed-effects model | <0.01** |
| Former HRT vs. never HRT | 7 | ||||
| Among all participants | 7 | 0.96 (0.90–1.02)a | 0 | Fixed-effects model | 0.16 |
| Among postmenopausal women | 4 | 0.96 (0.88–1.03)a | 0 | Fixed-effects model | 0.26 |
| Among participants ≥50 years old | 5 | 0.97 (0.90-1.04)a | 0 | Fixed-effects model | 0.37 |
| Case-control studies | 9 | ||||
| Ever HRT vs. never HRT | 9 | ||||
| Among all women | 9 | 0.75 (0.69–0.81)b | 0 | Fixed-effects model | <0.01** |
| Among female non-smokers | 5 | 0.76 (0.66–0.87)b | 36.8 | Fixed-effects model | <0.01** |
| In non-small lung cancer | 3 | 0.79 (0.69–0.91)b | 0 | Fixed-effects model | <0.01** |
| BMI <25 | 3 | 0.67 (0.55-0.81)b | 0 | Fixed-effects model | <0.01** |
| 25≤ BMI <30 | 3 | 0.77 (0.59-1.01)b | 0 | Fixed-effects model | 0.06 |
| 30≤ BMI | 3 | 0.80 (0.54-1.17)b | 0 | Fixed-effects model | 0.25 |
a, pooled relative risk; b, pooled odds ratio; *, P≤0.05; **, P≤0.01. RE, risk estimates; BMI, body mass index; BMI <25, normal/underweight; 25≤ BMI <30, overweight; HRT, hormone replacement therapy; 30≤ BMI, obese.