Association of body composition with odds of breast cancer by molecular subtype: analysis of the Mechanisms for Established and Novel Risk Factors for Breast Cancer in Nigerian Women (MEND) study
Authors: Akinyemiju Tomi , Jones Kelley , Gupta Anjali , Oyekunle Taofik , Saraiya Veeral , Deveaux April , Salako Omolola , Hall Allison , Alatise Olusegun , Ogun Gabriel , Adeniyi Adewale , Ayandipo Omobolaji , Olajide Thomas , Olasehinde Olalekan , Arowolo Olukayode , Adisa Adewale , Afuwape Oludolapo , Olusanya Aralola , Adegoke Aderemi , Tollefsbol Trygve O. , Arnett Donna ,   H3 Africa Kidney Research Network, Ajayi Samuel , Raji Yemi , Olanrewaju Timothy , Osafo Charlotte , Ulasi Ifeoma , Asinobi Adanze , Winkler Cheryl A. , Burke David , Arogundade Fatiu , Ekem Ivy , Plange-Rhule Jacob , Mamven Manmak , Mate-kole Michael , Amodu Olukemi , Cooper Richard , Antwi Sampson , Adeyemo Adebowale , Ilori Titilayo , Adabayeri Victoria , Nyarko Alexander , Ghansah Anita , Amos-Abanyie Ernestine Kubi , Akyaw Priscilla Abena , Kimmel Paul L. , Salako Babatunde L. , Parekh Rulan S. , Tayo Bamidele , Gbadegesin Rasheed , Boehnke Michael , Lyons Robert , Brosius Frank Chip , Clauw Daniel , Adindu Chijioke , Bewaji Clement , Tannor Elliot Koranteng , Okyere Perditer , Ijoma Chuba , Tiffin Nicki , Gamiedien Junaid , Hildebrandt Friedhelm , Odenigbo Charles , Jisieike-Onuigbo Nonyelun , Modebe Ifeoma , Abdu Aliyu , Obiagwu Patience , Okoye Ogochukwu , Solarin Adaobi , Amira Toyin , Esezobor Christopher , Makusidi Muhammad , Saraf Santosh , Gordeuk Victor , Ashuntangtang Gloria , Guenkam Georgette , Kazi Folefack , Adedoyin Olanrewaju , McCullough Mignon , Nourse Peter , Okafor Uche , Anigilaje Emmanuel , Ikpebe Patrick , Odetunde Tola , Mbanefo Ngozi , Olowu Wasiu , Tindana Paulina , Awobusuyi Olubenga , Ogedegbe Olugbenga , Olabisi Opeyemi , Skorecki Karl , Adebowale Ademola , Kretzler Matthias , Hodgin Jeffrey , Adu Dwomoa , Ojo Akinlolu , Boima Vincent , Daramola Adetola 
Published: September 2021

Abstract
Background
The association between obesity and breast cancer (BC) has been extensively studied among US, European and Asian study populations, with often conflicting evidence. However, despite the increasing prevalence of obesity and associated conditions in Africa, the continent with the highest age-standardized BC mortality rate globally, few studies have evaluated this association, and none has examined in relation to molecular subtypes among African women. The current analysis examines the association between body composition, defined by body mass index (BMI), height, and weight, and BC by molecular subtype among African women.

Methods
We estimated odds ratios (ORs) and 95% confidence intervals (95% CI) for the association between measures of body composition and BC and molecular subtypes among 419 histologically confirmed cases of BC and 286 healthy controls from the Mechanisms for Established and Novel Risk Factors for Breast Cancer in Women of Nigerian Descent (MEND) case-control study.

Results
Higher BMI (aOR: 0.79; 95% CI: 0.67, 0.95) and weight (aOR: 0.83; 95% CI: 0.69, 0.98) were associated with reduced odds of BC in adjusted models, while height was associated with non-statistically significant increased odds of BC (aOR: 1.07, 95% CI: 0.90, 1.28). In pre/peri-menopausal, but not post-menopausal women, both higher BMI and weight were significantly associated with reduced odds of BC. Further, higher BMI was associated with reduced odds of Luminal A, Luminal B, and HER2-enriched BC among pre/peri-menopausal women, and reduced odds of triple-negative BC among post-menopausal women.

Conclusions
Higher BMI and weight were associated with reduced odds of BC overall and by molecular subtype among West African women. Larger studies of women of African descent are needed to definitively characterize these associations and inform cancer prevention strategies.