Anthropometric variables in relation to risk of breast cancer in Nigerian women

Chinedu C Okoli; Uzoamaka R Ebubedike; Stanley N C Anyanwu; Chinemelum D Emegoakor; Gabriel U Chianakwana; Eric Ihekwoaba; Ochomma A Egwuonwu; Henry Nzeako

doi:10.4103/ijmh.IJMH_35_19

ORIGINAL ARTICLES

Year : 2020 | Volume : 25 | Issue : 2 | Page : 132-137

Anthropometric variables in relation to risk of breast cancer in Nigerian women

Chinedu C Okoli¹, Uzoamaka R Ebubedike², Stanley N C Anyanwu¹, Chinemelum D Emegoakor¹, Gabriel U Chianakwana¹, Eric Ihekwoaba¹, Ochomma A Egwuonwu¹, Henry Nzeako¹
¹ Nnamdi Azikiwe University Teaching Hospital, Breast Tumour Board, PMB 5025, Nnewi, Nigeria; Department of Surgery, Nnamdi Azikiwe University Teaching Hospital, PMB 5025, Nnewi, Nigeria
² Nnamdi Azikiwe University Teaching Hospital, Breast Tumour Board, PMB 5025, Nnewi, Nigeria; Department of Radiology, Nnamdi Azikiwe University Teaching Hospital, PMB 5025, Nnewi, Nigeria

Date of Submission	22-Nov-2019
Date of Decision	11-Mar-2020
Date of Acceptance	27-Apr-2020
Date of Web Publication	29-Jul-2020

Correspondence Address:
Chinedu C Okoli
Department of Surgery, Nnamdi Azikiwe University Teaching Hospital PMB 5025 Nnewi, Nigeria, Nnamdi Azikiwe University Teaching Hospital Breast Tumour Board, PMB 5025, Nnewi.
Nigeria

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijmh.IJMH_35_19

Abstract

Background: Breast cancer is the most prevalent cancer and the second leading cause of cancer death among women, and understanding how obesity impacts this disease has important public health implications. Materials and Methods: This study was a prospective study that involved 100 participants managed for breast diseases from May 2015 to April 2017 at Nnamdi Azikiwe University Teaching Hospital, Nnewi (NAUTH). All the participants were formally diagnosed using clinical evaluation and core tissue biopsy. Waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), height and weight were measured, subsequently body-mass index was estimated as a ratio of an individual’s weight (kg)/height (m²). Results: The mean age (SD) of the subjects was 41.6 (9.3) years; all the participants were women. The mean (SD) body-mass index, WC and WHR of all the participants were 27.57 (6.85) kg/m²; 87.70 (16.36)cm and 0.87 (0.07) respectively. The mean (SD) body-mass index of pre-menopausal and post-menopausal were 26.52 (6.62) kg/m² and 30.60 (6.71) kg/m² respectively. The mean (SD) WHR of pre-menopausal and post-menopausal were 0.87 (0.06) and 0.90 (0.08) respectively, whereas the mean (SD) WC of pre-menopausal and post-menopausal were 85 (15.0) cm and 94.85 (17.97) respectively, thus individuals who were older were more likely to be overweight or obese than younger persons. Conclusion: This study findings emphasize the importance of considering wide WC and high WHR while implementing risk reduction strategies of breast cancer in younger women. Future studies to elucidate the significance of this findings in larger cohorts are needed.

Keywords: Breast cancer, height, obesity, waist circumference, waist- hip ratio, weight

How to cite this article:
Okoli CC, Ebubedike UR, Anyanwu SN, Emegoakor CD, Chianakwana GU, Ihekwoaba E, Egwuonwu OA, Nzeako H. Anthropometric variables in relation to risk of breast cancer in Nigerian women. Int J Med Health Dev 2020;25:132-7

How to cite this URL:
Okoli CC, Ebubedike UR, Anyanwu SN, Emegoakor CD, Chianakwana GU, Ihekwoaba E, Egwuonwu OA, Nzeako H. Anthropometric variables in relation to risk of breast cancer in Nigerian women. Int J Med Health Dev [serial online] 2020 [cited 2022 Aug 12];25:132-7. Available from: https://www.ijmhdev.com/text.asp?2020/25/2/132/291058

Introduction

Approximately 13% of the world’s adult population (11% of men and 15% of women) were obese in 2016, making obesity a major health problem globally.^[1] Previously considered a high-income country problem, recent global data from the World Health Organization (WHO) indicate that the prevalence of obesity is on the increase in the developing world particularly in urban settings.^[1] Although the impact of obesity on some chronic health conditions such as diabetes and heart disease is well known, our understanding of the effect of obesity on cancer is recently being elucidated.^[2] Several studies have linked obesity with higher cancer mortality,^[3],[4] whereas studies that may establish a causal link are still ongoing. Recently, many authors have found an increased association between obesity and a higher risk of some malignant conditions.^[4] As breast cancer is the most prevalent cancer and the second leading cause of cancer death among women,^[5] understanding how obesity impacts this disease has important public health implications.

An inverse association between general obesity and premenopausal breast cancer risk has been reported by some authors.^[6],[7] This finding is supported by a large meta-analysis by Renehan et al.^[8] involving 20 data sets, which included >2.5 million women and 7930 premenopausal breast cancers. They showed that premenopausal breast cancer risk is reduced by approximately 8% per 5kg/m² body mass index (BMI) increase. It must be noted that the lower premenopausal breast cancer risk with obesity is not observed in all studies.^[9],[10] Furthermore, two meta-analyses have reported differences between ethnicities, showing an inverse relationship between increased BMI and premenopausal breast cancer risk in most of the groups, but a positive association in the Asian women.^{[8],[9],[10],[11]} The association of central obesity with breast cancer has also been reported with some authors suggesting a stronger relationship with breast cancer when compared with BMI.^[12] Although the specific effect of central obesity on breast cancer risk is not yet clear, a systematic review by Harvie et al.^[13] suggests a lower risk of breast cancer in postmenopausal women with the smallest waist (compared with the largest) and a 24% lower risk in women with the smallest waist-to-hip ratio (WHR). In premenopausal women, however, pooled results suggest that measurement of waist or WHR has little effect on the risk of breast cancer. On the contrary, Nagrani et al.^[14] reported that central obesity is a key risk factor for breast cancer irrespective of menopausal or hormonal receptor status in Indian women with no history of hormone replacement therapy. A central (abdominal) fat distribution pattern is better assessed using waist circumference (WC) or WHR.^[15]

It should be noted that a large number of studies have been performed on predominantly Caucasian cohorts with paucity of data on cohorts African or Nigerian origin. However, a previous study on this subject in conducted among Nigerian women over a decade ago failed to show any association between breast cancer risk and obesity in urbanized Nigerian women.^[16] This study defined obesity using BMI alone (a measure of overall adiposity) and the relationship between central obesity and breast cancer was not studied. With this in mind, the authors aimed to determine the association between anthropometric variables (BMI, WC or WHR, and breast cancer in premenopausal and postmenopausal women. We hypothesize that central and general obesities are not associated with premenopausal and postmenopausal breast cancer, respectively. We believe that the findings of the study will impact on our strategy of preventive management of breast cancer.

Materials and Methods

The setting

It was carried out in a tertiary hospital in Southeastern Nigeria. It has a Breast Tumour Board that provides an oversight function, which was formed during this study. The surgical units administer chemotherapy for breast cancer patients because of the absence of a medical oncologist in our hospital.

Subjects

This study was a prospective study that involved 100 participants managed for breast diseases from May 2015 to April 2017 who were randomly selected from the pool of patients who attended the breast cancer clinic. All the participants were formally diagnosed using clinical evaluation and core tissue biopsy.

Data collection

Trained research assistants measured individual height with a rigid tape measure, following the WHO multinational monitoring of trends and determinants in cardiovascular disease criteria.^[17] Height was measured to the nearest centimeter using a rigid tape, whereas the WC was measured at the end of several consecutive natural breaths, at a level parallel to the floor, the midpoint between the top of the iliac crest and the lower margin of the last palpable rib in the midaxillary line. The hip circumference was measured at the largest circumference of the buttocks. Both were measured using a stretch-resistant tape. Weight was estimated using the Omron body sensor (OMRON HBF-510 W Full Body Sensor Body Composition Monitor Scale, China). The BMI was estimated as a ratio of an individual’s weight (kg)/height (m²).

Statistical analysis

The continuous variables were analyzed with descriptive statistics including means (average), median, standard deviation (SD), and range. The Statistical Program for the Social Sciences for Windows, version 20.0 (IBM, Armonk, New York) was used for statistical analysis. The BMI was calculated using the following equation (weight [kg]/height [m²]). Obesity was defined as a BMI≥30kg/m², WC of >88cm in females, and the WHR of ≥0.85cm for females. The values were approximated to two decimal places. Menopause was defined as the permanent cessation of menses due to prior bilateral oophorectomy, or age ≥60 years, or age <60 years and amenorrheic for 12 or more months in the absence of chemotherapy, hormonal therapy, or ovarian suppression and follicle-stimulating hormone (FSH) and estradiol in the postmenopausal range. The mean differences in the two groups were determined using independent T tests, whereas chi-square tests were used to compare differences in the proportions of categorical variables. Statistical significance was inferred when P < 0.05.

Ethics

The study was conducted according to the Nigerian National Code for Health Research Ethics and the Declaration of Helsinki for medical research in humans.^[18] Ethical approval to conduct this study was obtained from the Nnamdi Azikiwe University Teaching Hospital Ethics Committee. Individuals were informed about the study and were requested to consent before participating in the study.

Results

The mean age (SD) of the subjects was 41.6 (9.3) years; all the participants were women [Figure 1]. The mean (SD) BMI, WC, and WHR of all the participants were 27.57 (6.85) kg/m², 87.70 (16.36) cm, and 0.87 (0.07), respectively [Table 1]. The mean (SD) BMI of premenopausal and postmenopausal women were 26.52 (6.62) kg/m² and 30.60 (6.71) kg/m², respectively. The mean (SD) WHR of premenopausal and postmenopausal women were 0.87 (0.06) and 0.90 (0.08), respectively, whereas the mean (SD) WC of premenopausal and postmenopausal women were 85 (15.0) and 94.85 (17.97) cm, respectively. Thus, older individuals were more likely to be overweight or obese than younger persons [Table 2]. The prevalence of obesity in this study differs from the different parameters assessed. It is highest for WHR (61.9%) and lowest for BMI (34.1%). The prevalence of obesity based on WC is 45.2%. Fifty-three percent of the participants had malignant breast diseases, whereas 47% of them had benign breast masses.

Figure 1: Age distribution of the participants

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Table 1: Anthropometric parameters and age of the participants

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Table 2: Anthropometric parameters of both premenopausal and postmenopausal women that participated in the study

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Discussion

Our study showed that participants with breast cancer had consistently higher BMI, WC, and WHR, as shown in [Table 3]. This finding agreed with other reports in the literature.^[15],[16] Although the exact mechanism by which obesity increases breast cancer risk has not been fully elucidated, some authors have proposed that it may be due to the effect of hyperinsulinemia. High BMI, WC, and WHR are associated with metabolic syndrome. Generally metabolic syndrome patients have increased levels of circulating insulin and insulin-like growth factor 1 (IGF-1). It is proposed that this state of hyperinsulinemia reduces sex hormone-binding globulin levels and increases estrogen bioavailability, which may increase breast cancer risk.^[19]

Table 3: Anthropometric parameters of the participants with malignant and benign breast diseases

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In our study, when the pooled analysis was stratified based on menopausal status, we found that premenopausal women with breast cancer were more likely to have central obesity (significantly wider WC and higher WHR) when compared with postmenopausal women, as shown in [Table 4] and [Table 5]. Therefore, central obesity appeared to be a key risk factor for BC in premenopausal women with no history of hormone replacement therapy in our study. Similar finding was reported by an Indian case-control study, which showed that greater WC and WHR were associated with an elevated risk of premenopausal triple-negative breast cancer (TNBC), whereas high BMI was not associated with either premenopausal or postmenopausal breast cancers.^[14] Also, two meta-analyses reported a higher risk of developing TNBC in obese premenopausal women.^[20],[21] Breast cancer profile in our environment suggests an over-representation of TNBC.^[22],[23] TNBCs lack expression of ER, PR, and human epidermal growth factor receptor 2 (HER2) and have a very aggressive disease course.

Table 4: Anthropometric parameters of the premenopausal and postmenopausal participants with malignant and benign breast diseases

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Table 5: Proportions of premenopausal and postmenopausal obese participants with malignant and benign breast diseases based on BMI, WC, and WHR

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We also noted that there was no significant difference between the BMI of premenopausal and postmenopausal women with breast cancer in the index study. Although this agreed with reports by Nagrani et al.^[14] and Adebamowo et al.,^[16] some other studies, particularly those carried out in the Western population, showed a reduced risk of premenopausal breast cancer with high BMI, but increased risk in postmenopausal breast cancer in patients with high BMI.^[6],[7] However, it is pertinent to note that not all the observational studies in the Western population showed the inverse relationship between high BMI and premenopausal breast cancer. The Cancer and Steroid Hormone (CASH) population-based case-control study with 3432 breast cancers^[24] reported a strong positive association between increased BMI and premenopausal breast cancer risk. Thus, it is our view that the harmful effect(s) of central obesity and/or general obesity remains complex and the specific link between anthropometric measurements and breast cancer risk in different studies remains uncertain. These may be as a result of many influencing factors such as ethnicity, lifestyle, and reproductive status.^[15]

Our study had some unavoidable limitations. First, this research was a hospital-based study conducted in one center; therefore, to generalize the results for a larger group, the study should have involved more hospitals. Second, we did not consider the effect of social class and premorbid anthropometric parameters in our analysis because of the sample size. However, we were able to show that malignant breast diseases are more common in younger women with central obesity (high WC and high WHR).

In conclusion, the effects of central obesity on the risk of breast cancer differ in premenopausal and postmenopausal women. In premenopausal women, central obesity is associated with a higher risk of breast cancer. However, in postmenopausal women, central obesity is not associated with a higher risk of breast cancer. Even though we are yet to fully understand the implication of the recent rise in obesity prevalence on cancer incidence and outcomes, the time has come for systematic weight loss intervention through standardized diet and exercise programs considering wide WC and high WHR while implementing risk reduction strategies of breast cancer in younger women. One could argue, based on compelling data from observational studies in Western Population, future studies should aim to elucidate the significance of these findings in larger cohorts in African or black population.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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