Effect of Body Mass Index on Breast Cancer during Premenopausal and Postmenopausal Periods: A Meta-Analysis

Abstract

ObjectiveThere is no universal consensus on the relationship between body mass index (BMI) and breast cancer. This meta-analysis was conducted to estimate the overall effect of overweight and obesity on breast cancer risk during pre- and post-menopausal period.Data SourcesAll major electronic databases were searched until April 2012 including Web of Knowledge, Medline, Scopus, and ScienceDirect. Furthermore, the reference lists and related scientific conference databases were searched.Review MethodsAll prospective cohort and case-control studies investigating the association between BMI and breast cancer were retrieved irrespective of publication date and language. Women were assessed irrespective of age, race and marital status. The exposure of interest was BMI. The primary outcome of interest was all kinds of breast cancers confirmed pathologically. Study quality was assessed using the checklist of STROBE. Study selection and data extraction were performed by two authors separately. The effect measure of choice was risk ratio (RRi) and rate ratio (RRa) for cohort studies and odds ratio (OR) in case-control studies.ResultsOf 9163 retrieved studies, 50 studies were included in meta-analysis including 15 cohort studies involving 2,104,203 subjects and 3,414,806 person-years and 35 case-control studies involving 71,216 subjects. There was an inverse but non-significant correlation between BMI and breast cancer risk during premenopausal period: OR = 0.93 (95% CI 0.86, 1.02); RRi = 0.97 (95% CI 0.82, 1.16); and RRa = 0.99 (95% CI 0.94, 1.05), but a direct and significant correlation during postmenopausal period: OR = 1.15 (95% CI 1.07, 1.24); RRi = 1.16 (95% CI 1.08, 1.25); and RRa = 0.98 (95% CI 0.88, 1.09).ConclusionThe results of this meta-analysis showed that body mass index has no significant effect on the incidence of breast cancer during premenopausal period. On the other hand, overweight and obesity may have a minimal effect on breast cancer, although significant, but really small and not clinically so important.

The Correlation between Body Mass Index and Breast Cancer Risk or Estrogen Receptor Status in Okinawan Women

“…Results of previous meta-analysis studies suggested that high BMI during premenopausal period may protect against breast cancer development in later life, although the association did not reach statistical significance (Cheraghi et al 2012). This trend has been also reported in several other studies showing a significant inverse association between body weight and breast cancer incidence in premenopausal women (Harris et al 2011a, b).…”

“…This trend has been also reported in several other studies showing a significant inverse association between body weight and breast cancer incidence in premenopausal women (Harris et al 2011a, b). In contrast, the same meta-analysis demonstrated that increased BMI during postmenopausal period could significantly increase the risk of breast cancer development (Cheraghi et al 2012). The increased risk in postmenopausal women associated with being overweight and/or obese is due to the fact that adipose tissue is the major source of estrogen following menopause (Cauley et al 1989;Key et al 2003).…”

Mechanics behind Breast Cancer Prevention - Focus on Obesity, Exercise and Dietary Fat

“…For example, obesity during pre-teen years (ages 5-10) is inversely related to breast cancer risk (Baer et al, 2010). On the other hand, obesity after menopause is positively related to breast cancer incidence (Bates and Carmichael, 2004;Lahmann et al, 2004;Cheraghi et al, 2012;Phipps et al, 2012;Xu et al, 2012). Although this is fairly well established, the relationship between premenopausal obesity and breast cancer risk remains less clear.…”

Obesidad y cáncer en Chile: estimación de las fracciones atribuibles poblacionales

“…Tercero, las cohortes que han evaluado la relación entre cáncer y obesidad se han centrado en personas de edad media, lo que probablemente no refleja los riesgos a edades jóvenes o envejecidas 16 . Cuarto, los estimados de FAP% para cáncer de mama debieran ser calculados diferencialmente en mujeres premenopáusicas y postmenopáusicas, dado que la evidencia epidemiológica señala que la obesidad estaría asociada a un mayor riesgo de este cáncer sólo en postmenopáusicas 17 . Finalmente, los datos actuales de incidencia representan el impacto por exposición a obesidad en décadas pasadas, donde las prevalencias eran más bajas que las actuales 18 .…”