Body Mass Index and Risk of Breast Cancer: A Systematic Review and Meta-Analysis in Iran

Abstract

Background: Various studies in Iran on the role of BMI higher than normal (BMI ≥25) on breast cancer have reported different results.Objective: The aim of this systematic review and meta-analysis is to estimate the odds ratio of overweightness and obesity as risk factors of breast cancer in studies conducted in Iran.Evidence Acquisition: The following main databases were searched from 2004 to 2014 to find related articles: PubMed, Web of Science, Google Scholar, Scopus and Iranian databases (SID and Magiran), breast cancer conferences held in Iran, key journals, and the references of the selected articles. Keywords were: Cancer, Tumor, Neoplasm, Neoplasia, Carcinoma, Malignancy, Malignant, Benign. The combination with OR and added it to search field with AND to words such as Iran and breast was used as the search strategy. The observational studies (cohort, case-control, and cross-sectional) in Iran that had reported the relation between BMI and breast cancer in Persian and English were searched. There were no limitations in terms of age, race, ethnicity, and marital status for women. The exposure was BMI ≥ 25 (overweight and obese) and the outcome was breast cancer with pathological confirmation.Two reviewers separately used the STROBE checklist for quality assessment, critically appraised papers and extract the data. The overall estimate was the odds ratio. Results:Of 4396 studies, after evaluation of heterogeneity, 7 case-control studies with a sample size of 33552 were included in the meta-analysis. A significant relation was observed between obesity (OR = 1.81, 95% CI = 1.24 -2.64) and odds of breast cancer. A significant relation was also observed between overweightness and odds of breast cancer (OR = 1.46, 95% CI = 1.13 -1.89).Conclusions: Meta-analysis results showed a significant relation between obesity and overweight with risk of breast cancer in Iranian women. We recommended Iranian women to be aware of the effect of weight on breast cancer and encouraged them to decrease their weight via physical activity and diet control.

Cancer in Iran 2008 to 2025: Recent incidence trends and short‐term predictions of the future burden

“…Our results indicate a 63.0% increase in the number of new breast cancers among females between 2016 and 2025. A rising prevalence of obesity 25,26 as a risk factor for breast cancer in Iranian women 28,29 may partly explain the rise, while late age at first pregnancy, nulliparity and a limited duration of breast feeding may also increase breast cancer risk. 30,31 The most notable shifts observed for reproductive factors in Iranian women were declines in parity and older age at the first pregnancy.…”

The impact of BMI on breast cancer – an updated systematic review and meta-analysis

“…[ 1 , 2 ] In 2012, the International Agency for Research on Cancer reported 1.7 million breast cancer new cases, with 6.3 million new patients diagnosed in the previous 5 years. [ 3 ] Every year, almost 1.5 million women worldwide are diagnosed with breast cancer. [ 4 ] Breast cancer is a type of metastatic cancer that can spread to other parts of the body, including the bones, lungs, liver, and brain, making it uncurable.…”

“…[ 9 ] Overweight, lack of physical activity, and obesity have been identified as the major risk factors in high and middle-income nations, accounting for 18%. [ 3 ] Multiple research relates it to the fact that adipocytes cause chronic inflammation in obesity leading to a rise in the systemic levels of cytokines as interleukin 6 and tumor necrosis factor. [ 10 ] Obesity is a known risk factor for metabolic syndrome, type 2 diabetes, and heart attacks [ 11 ] ; the latter is still the leading cause of death in women with early-stage breast cancer.…”

Association between interleukin 4 (IL-4) VNTR, gene polymorphism, and breast cancer susceptibility in Iranian population: experimental and web base analysis

“…There are legion risk factors related to breast cancer such as: age, genetic background, hormonal condition, obesity, exposure to radiation and chemical carcinogens. Histopathological markers, including the expression of sex hormone receptors and human epidermal growth factor receptor (HER2) are commonly used as diagnostic means to contribute to choosing an effective approach in clinical treatment (3)(4)(5)(6). Almost 60 to 70 % of breast cancer cases are ER/PR positive and so tumor growth is dependent on estro-gen. And also, 20 to 25 % over-express Her2, which are more aggressive (7,8).…”