Table 5.
Mediation effect of baseline spirometry on the associations between early menopause and mortality in females with natural menopause
| Outcome | Mediator | Early menopause-Outcome (β [SE], P)1 | Mediation effect | ||
|---|---|---|---|---|---|
|
| |||||
| Without mediator | With mediator | PM2 | Pperm3 | ||
| Mortality (All-cause) | FEV1 | 0.33 (0.15), 0.02 | 0.19 (0.15), 0.20 | 42.4% | <0.01 |
| FVC | 0.24 (0.15), 0.11 | 27.3% | <0.01 | ||
| FEV1/FVC | 0.25 (0.15), 0.09 | 24.2% | <0.01 | ||
| Mortality (LC) | FEV1 | 0.66 (0.31), 0.03 | 0.55 (0.32), 0.08 | 16.7% | <0.01 |
| FVC | 0.56 (0.32), 0.07 | 15.2% | <0.01 | ||
| FEV1/FVC | 0.63 (0.31), 0.04 | 4.5% | 0.013 | ||
| Mortality (Cancer) | FEV1 | 0.55 (0.23), 0.01 | 0.47 (0.23), 0.04 | 14.5% | <0.01 |
| FVC | 0.48 (0.23), 0.03 | 12.7% | <0.01 | ||
| FEV1/FVC | 0.51 (0.23), 0.02 | 7.3% | <0.001 | ||
| Mortality (Respiratory) | FEV1 | 0.84 (0.21), <0.001 | 0.56 (0.22), 0.01 | 33.3% | <0.01 |
| FVC | 0.68 (0.22), <0.01 | 19.0% | <0.01 | ||
| FEV1/FVC | 0.65 (0.22), <0.01 | 22.6% | <0.01 | ||
LC: lung cancer; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; SE: standard error; PM: proportion mediated.
Early menopause was modeled in relation to mortality with and without adjustment for potential mediators using Cox regression. Covariates for adjustment included baseline values of age, packyears, overweight or obesity status (dummy variables with non-early BMI as the reference), ethnicity (two dummy variables for African American or other ethnicities with NHWs as the reference), and history of hormone therapy and LSS status (former and intermittent smokers with continuous smokers as the reference).
Proportion mediated following the formula PM=100*(β - β’)/β, where β is total effect of early menopause and β’ is the effect estimate of early menopause when controlling for baseline spirometry.
Pperm is derived after permutation for 200 times. For associations with PM <10%, permutation was conducted for 1000 times to generate the Pperm.