Relative Weight at Age 12 and Risk of Postmenopausal Breast Cancer

Abstract

Background: Early adolescent weight may affect the risk of postmenopausal breast cancer, and this association may be modified by a family history of breast or ovarian cancer in a first-degree relative, and/or estrogen (ER) and progesterone (PR) receptor status of the disease. Methods: Relative weight at age 12 years (above, below, or average weight compared with peers) and family history were ascertained using a mailed questionnaire in 1986, in the Iowa Women's Health Study, a prospective cohort study of postmenopausal women. Incident breast cancer cases (including ER and PR status) were identified using the Iowa Surveillance, Epidemiology, and End Results Cancer Registry. Relative risks (RR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression, and were adjusted for breast cancer risk factors, including body mass index at age 18 years and body mass index at study baseline.

Height and Body Size in Childhood, Adolescence, and Young Adulthood and Breast Cancer Risk According to Molecular Subtype in the Nurses' Health Studies

“…Two other studies, also found that the inverse association between childhood body size and breast cancer was strongest for triple negative tumors and those that over-expressed HER2 (34). While associations have also been observed only among ER+/PR+ (2) or ER+/PR− tumors (35), overall, the body of literature suggests that body size in early life may reduce risk of breast cancer in adulthood through sex hormone dependent and independent mechanisms. It was previously postulated that higher body fatness in early-life may be associated with higher levels of estrogen which could induce early breast differentiation thereby making breast cells less susceptible to malignant transformation (36).…”

The Premenopausal Breast Cancer Collaboration: A Pooling Project of Studies Participating in the National Cancer Institute Cohort Consortium

“…Higher adiposity in childhood and adolescence appears to be associated with a lower risk of breast cancer at both premenopausal (73, 76–78) and postmenopausal (77–79) ages. Whether further weight gain contributes to additional reductions in premenopausal breast cancer risk is not entirely clear (80, 81).…”

Fatores de risco e de proteção para câncer de mama: uma revisão sistemática

“…Bardia et al 26 consideraram o peso aos 12 anos de idade e o câncer de mama na pós-menopausa, pois existem hipóteses de que o maior IMC na adolescência seja um fator protetor para o câncer de mama tanto na pré-menopausa como na pós-menopausa. O mecanismo é desconhecido, mas se sabe que maiores níveis de insulina e IGF-1 na adolescência podem prejudicar o metabolismo ovariano, induzindo à anovulação.…”

“…O mecanismo é desconhecido, mas se sabe que maiores níveis de insulina e IGF-1 na adolescência podem prejudicar o metabolismo ovariano, induzindo à anovulação. Bardia et al 26 encontraram um RR de 0,85 (IC95%: 0,74-0,98) somente para mulheres que possuíam o peso aos 12 anos acima da média para a idade, comparando-se àquelas com peso na média para a respectiva idade.…”