Table 4.
Relative risk of cancer by menopausal hormone therapy (MHT) according to trajectories of body shape in women (Nurses’ Health Study)a
| Lean-stable | Lean-moderate increase | Lean-marked increase | Medium-stable | Heavy-stable/increase | P for interactionb | |
|---|---|---|---|---|---|---|
| Total cancer | ||||||
| Ever used MHT (N=6,834) | 1 (reference) | 1.03 (0.96–1.12) | 1.10 (1.02–1.20) | 1.04 (0.97–1.12) | 1.06 (0.97–1.17) | <0.001 |
| Never used MHT (N=4,594) | 1 (reference) | 1.12 (1.02–1.23) | 1.26 (1.14–1.39)e | 1.04 (0.94–1.14) | 1.27 (1.14–1.42)e | |
| Obesity-related cancerg | ||||||
| Ever used MHT (N=3,776) | 1 (reference) | 1.10 (0.99–1.21) | 1.25 (1.12–1.39) | 1.01 (0.92–1.12) | 1.12 (0.98–1.27) | <0.001 |
| Never used MHT (N=2,606) | 1 (reference) | 1.32 (1.15–1.51)c | 1.64 (1.43–1.87)e | 1.07 (0.93–1.23) | 1.57 (1.35–1.82)e | |
| Colorectal cancer | ||||||
| Ever used MHT (N=572) | 1 (reference) | 0.95 (0.73–1.24) | 1.14 (0.86–1.51) | 1.00 (0.78–1.28) | 1.45 (1.07–1.97) | 0.92 |
| Never used MHT (N=556) | 1 (reference) | 0.97 (0.73–1.29) | 1.30 (0.98–1.72) | 1.03 (0.78–1.35) | 1.36 (0.99–1.85) | |
| Pancreatic cancer | ||||||
| Ever used MHT (N=196) | 1 (reference) | 1.06 (0.68–1.65) | 1.11 (0.69–1.78) | 0.97 (0.63–1.49) | 1.23 (0.72–2.09) | 0.79 |
| Never used MHT (N=127) | 1 (reference) | 1.43 (0.75–2.72) | 1.85 (0.97–3.51) | 1.54 (0.83–2.86) | 1.76 (0.87–3.59) | |
| Kidney cancer | ||||||
| Ever used MHT (N=117) | 1 (reference) | 0.92 (0.50–1.69) | 1.77 (0.99–3.16) | 0.91 (0.51–1.61) | 1.53 (0.78–3.00) | 0.36 |
| Never used MHT (N=94) | 1 (reference) | 2.20 (0.95–5.13) | 2.38 (1.02–5.55) | 1.48 (0.62–3.54) | 2.96 (1.24–7.10) | |
| Postmenopausal breast cancer | ||||||
| Ever used MHT (N=2,137) | 1 (reference) | 1.25 (1.10–1.43) | 1.33 (1.15–1.54) | 1.04 (0.91–1.18) | 0.98 (0.82–1.17) | 0.17 |
| Never used MHT (N=1,307) | 1 (reference) | 1.41 (1.17–1.70) | 1.58 (1.31–1.91) | 1.09 (0.90–1.32) | 1.36 (1.09–1.68)c | |
| Endometrial cancer | ||||||
| Ever used MHT (N=390) | 1 (reference) | 0.77 (0.56–1.06) | 0.93 (0.66–1.29) | 0.87 (0.65–1.17) | 1.41 (1.00–1.99) | <0.001 |
| Never used MHT (N=273) | 1 (reference) | 2.19 (1.23–3.90)e | 4.50 (2.59–7.79)f | 1.42 (0.78–2.59) | 5.25 (2.99–9.23)f | |
| Ovarian cancer | ||||||
| Ever used MHT (N=297) | 1 (reference) | 0.84 (0.58–1.21) | 0.91 (0.62–1.35) | 1.11 (0.80–1.53) | 0.85 (0.53–1.35) | 0.008 |
| Never used MHT (N=178) | 1 (reference) | 0.91 (0.58–1.41) | 0.92 (0.58–1.45) | 0.49 (0.30–0.80)d | 0.79 (0.46–1.34) |
Abbreviations: CI, confidence interval; RR, relative risk.
Follow-up started at age 62. RRs were estimated from multivariable Cox proportional hazards model with adjustment for the same set of covariates as in Table 1.
Global likelihood ratio test with 4 degrees of freedom was used to compare the model with the product terms between MHT use (binary: ever vs. never use) and the trajectory groups (indicator variables for the 4 non-reference groups) to the model without these terms.
P for interaction≤0.05, >0.01 by individual Wald test for each of the non-reference trajectory groups. A product term was created by multiplying the binary variable for each of the trajectory groups (1, non-reference group under test, 0, reference group) and the binary MHT variable (ever vs. never).
P for interaction≤0.01, >0.001 by individual Wald test.
P for interaction≤0.001, >0.0001 by individual Wald test.
P for interaction≤0.0001 by individual Wald test.
Including cancers of the colorectum, esophagus (adenocarcinoma only), pancreas, kidney, breast (postmenopause), endometrium, ovaries, liver, and gallbladder.