BMI and breast cancer risk around age at menopause.
Cancer Epidemiol
; 89: 102545, 2024 Apr.
Article
en En
| MEDLINE
| ID: mdl-38377945
ABSTRACT
BACKGROUND:
A high body mass index (BMI, kg/m2) is associated with decreased risk of breast cancer before menopause, but increased risk after menopause. Exactly when this reversal occurs in relation to menopause is unclear. Locating that change point could provide insight into the role of adiposity in breast cancer etiology.METHODS:
We examined the association between BMI and breast cancer risk in the Premenopausal Breast Cancer Collaborative Group, from age 45 up to breast cancer diagnosis, loss to follow-up, death, or age 55, whichever came first. Analyses included 609,880 women in 16 prospective studies, including 9956 who developed breast cancer before age 55. We fitted three BMI hazard ratio (HR) models over age-time constant, linear, or nonlinear (via splines), applying piecewise exponential additive mixed models, with age as the primary time scale. We divided person-time into four strata premenopause; postmenopause due to natural menopause; postmenopause because of interventional loss of ovarian function (bilateral oophorectomy (BO) or chemotherapy); postmenopause due to hysterectomy without BO. Sensitivity analyses included stratifying by BMI in young adulthood, or excluding women using menopausal hormone therapy.RESULTS:
The constant BMI HR model provided the best fit for all four menopausal status groups. Under this model, the estimated association between a five-unit increment in BMI and breast cancer risk was HR=0.87 (95% CI 0.85, 0.89) before menopause, HR=1.00 (95% CI 0.96, 1.04) after natural menopause, HR=0.99 (95% CI 0.93, 1.05) after interventional loss of ovarian function, and HR=0.88 (95% CI 0.76, 1.02) after hysterectomy without BO.CONCLUSION:
The BMI breast cancer HRs remained less than or near one during the 45-55 year age range indicating that the transition to a positive association between BMI and risk occurs after age 55.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Mama
/
Menopausia
Límite:
Adult
/
Female
/
Humans
/
Middle aged
Idioma:
En
Revista:
Cancer Epidemiol
Asunto de la revista:
EPIDEMIOLOGIA
/
NEOPLASIAS
Año:
2024
Tipo del documento:
Article
Pais de publicación:
Países Bajos