title: Body weight and risk of breast cancer in BRCA1/2 mutation carriers.
abstract: Obesity is an established risk factor for postmenopausal breast cancer in the general population. However, it is still unclear whether this association also exists in BRCA1/2 mutation carriers. We investigated the association between self-reported anthropometric measures and breast cancer risk in a nationwide retrospective cohort study, including 719 BRCA1/2 carriers, of whom 218 had been diagnosed with breast cancer within 10 years prior to questionnaire completion. All time-varying Cox proportional hazards analyses were stratified by menopausal status. For premenopausal breast cancer, no statistically significant associations were observed for any of the anthropometric measures. The association between body mass index (BMI) at age 18 and premenopausal breast cancer risk suggested a trend of decreasing risk with increasing BMI (HR(22.50-24.99 vs. 18.50-22.49) = 0.83, 95% CI = 0.47-1.44 and HR(≥ 25.00 vs. 18.50-22.49) = 0.41, 95% CI = 0.13-1.27). For postmenopausal breast cancer, being 1.67 m and taller increased the risk 1.7-fold (HR = 1.67, 95% CI = 1.01-2.74) when compared to a height <1.67 m. Compared with a current body weight < 72 kg, a current body weight of ≥ 72 kg increased the risk of postmenopausal breast cancer 2.1-fold (95% CI = 1.23-3.59). A current BMI of ≥ 25.0 kg/m², an adult weight gain of 5 kg or more, and a relative adult weight gain of 20% or more were all non-significantly associated with a 50-60% increased risk of postmenopausal breast cancer [HR = 1.46 (0.86-2.51), HR = 1.56 (95% CI = 0.85-2.87), and HR = 1.60 (95% CI = 0.97-2.63), respectively], when compared with having a healthy or stable weight. No associations for body weight or BMI at age 18 were observed. In conclusion, menopausal status seemed to modify the association between body weight and breast cancer risk among BRCA1/2 carriers. We observed no clear association between body weight and premenopausal breast cancer, while overweight and weight gain increased postmenopausal breast cancer risk. Carriers may reduce their risk of postmenopausal breast cancer by maintaining a healthy body weight throughout life.
authors: Department of Epidemiology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors: Peggy
authors: P
authors: Manders
authors: Anouk
authors: A
authors: Pijpe
authors: Maartje J
authors: MJ
authors: Hooning
authors: Irma
authors: I
authors: Kluijt
authors: Hans F A
authors: HF
authors: Vasen
authors: Nicoline
authors: N
authors: Hoogerbrugge
authors: Christi J
authors: CJ
authors: van Asperen
authors: Hanne
authors: H
authors: Meijers-Heijboer
authors: Margreet G E M
authors: MG
authors: Ausems
authors: Theo A
authors: TA
authors: van Os
authors: Encarna B
authors: EB
authors: Gomez-Garcia
authors: Richard M
authors: RM
authors: Brohet
authors: Flora E
authors: FE
authors: van Leeuwen
authors: Matti A
authors: MA
authors: Rookus
mesh_terms: D000328:Adult; D019313:BRCA1 Protein / Q000235:genetics*; D024682:BRCA2 Protein / Q000235:genetics*; D015992:Body Mass Index; D001835:Body Weight / Q000235:genetics*; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology; D016022:Case-Control Studies; D015331:Cohort Studies; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006580:Genetic Carrier Screening; D006801:Humans; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009426:Netherlands / Q000453:epidemiology; D009765:Obesity / Q000235:genetics; D016133:Polymerase Chain Reaction; D017698:Postmenopause / Q000235:genetics*; D017697:Premenopause / Q000235:genetics*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D015430:Weight Gain / Q000235:genetics; D055815:Young Adult
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D024682:BRCA2 Protein; C551750:BRCA2 protein, human; D004273:DNA, Neoplasm