Alcohol and risk of breast cancer in Mexican women

Temporal patterns of breast cancer incidence, mortality, disability-adjusted life years and risk factors in 12 South American Countries, 1990-2019: an examination using estimates from the global burden of disease 2019 study

BACKGROUND AND AIM

Breast cancer (BC) is one of the leading causes of cancer deaths in females in South America. This study aims to examine the BC burden in 12 South American countries between 1990 and 2019.

DATA AND METHODS

The estimates of BC burden and risk factors were procured from the Global Burden of Disease 2019 study for the period 1990-2019. Development levels of countries were gauged using socio-demographic index (SDI). Decomposition analysis was employed to categorize the change in incidence between 1990 and 2019 into three factors: population growth, population aging and age-specific incidence rate. Estimated annual percent changes were calculated for each country and bivariate association between country-level age-standardized rates and SDI was examined using pooled regression.

RESULTS

The age-standardized rates of breast cancer were the highest in Uruguay [incidence: 72.65 per 100,000 (55.79-92.57); mortality: 29.97 per 100,000 (27.54-32.27); disability-adjusted life years (DALYs: 810.49 per 100,000 (746.22-884.55)] and lowest in Peru [incidence: 27.63 per 100,000 (20.44-36.85); mortality: 10.79 per 100,000 (8.14-14.11); DALYs: 318.27 per 100,000 (234.47-421.16)]. Mortality-to-incidence ratio (MIR) across countries varied from 0.30 in Colombia to 0.55 in Bolivia in 2019. SDI had a positive and strong association with age-standardized incidence rate [Formula: see text] and weaker positive association with age-standardized mortality rate [Formula: see text] and age-standardized DALYs rate [Formula: see text]. Most countries experienced more than 70% increase in incident cases owing to population aging and age-specific incidence rates. Alcohol Use, diet high in red meat and smoking contributed the maximum DALYs in most countries in 2019 whereas DALYs due to high body-mass index and high fasting plasma glucose increased most substantially between 1990 and 2019.

CONCLUSION

With increasing incidence, high MIR and rising BC burden due to modifiable risk factors, several public health interventions are required in South America focusing on prevention, BC awareness among general public, cost-effective early detection and treatments that suit the socio-economic setup of South American countries.

Disparities in breast cancer mortality among Latin American women: trends and predictions for 2030

BACKGROUND

Breast cancer is among the leading cause of cancer-related mortality among Latin American and Caribbean (LAC) women, but a comprehensive and updated analysis of mortality trends is lacking. The objective of this study was to determine the breast cancer mortality rates between 1997 and 2017 for LAC countries and predict mortality until 2030.

METHODS

We retrieved breast cancer deaths across 17 LAC countries from the World Health Organization mortality database. Age-standardized mortality rates per 100,000 women-years were estimated. Mortality trends were evaluated with Joinpoint regression analyses by country and age group (all ages, < 50 years, and ≥ 50 years). By 2030, we predict number of deaths, mortality rates, changes in population structure and size, and the risk of death from breast cancer.

RESULTS

Argentina, Uruguay, and Venezuela reported the highest mortality rates throughout the study period. Guatemala, El Salvador, and Nicaragua reported the largest increases (from 2.4 to 2.8% annually), whereas Argentina, Chile, and Uruguay reported downward trends (from - 1.0 to - 1.6% annually). In women < 50y, six countries presented downward trends and five countries showed increasing trends. In women ≥ 50y, three countries had decreased trends and ten showed increased trends. In 2030, increases in mortality are expected in the LAC region, mainly in Guatemala (+ 63.0%), Nicaragua (+ 47.3), El Salvador (+ 46.2%), Ecuador (+ 38.5%) and Venezuela (+ 29.9%).

CONCLUSION

Our findings suggest considerable differences in breast cancer mortality across LAC countries by age group. To achieve the 2030 sustainable developmental goals, LAC countries should implement public health strategies to reduce mortality by breast cancer.

Whole exome sequencing and replication for breast cancer among Hispanic/Latino women identifies FANCM as a susceptibility gene for estrogen-receptor-negative breast cancer

Introduction

Breast cancer (BC) is one of the most common cancers globally. Genetic testing can facilitate screening and risk-reducing recommendations, and inform use of targeted treatments. However, genes included in testing panels are from studies of European-ancestry participants. We sequenced Hispanic/Latina (H/L) women to identify BC susceptibility genes.

Methods

We conducted a pooled BC case-control analysis in H/L women from the San Francisco Bay area, Los Angeles County, and Mexico (4,178 cases and 4,344 controls). Whole exome sequencing was conducted on 1,043 cases and 1,188 controls and a targeted 857-gene panel on the remaining samples. Using ancestry-adjusted SKAT-O analyses, we tested the association of loss of function (LoF) variants with overall, estrogen receptor (ER)-positive, and ER-negative BC risk. We calculated odds ratios (OR) for BC using ancestry-adjusted logistic regression models. We also tested the association of single variants with BC risk.

Results

We saw a strong association of LoF variants in FANCM with ER-negative BC (p=4.1×10-7, OR [CI]: 6.7 [2.9-15.6]) and a nominal association with overall BC risk. Among known susceptibility genes, BRCA1 (p=2.3×10-10, OR [CI]: 24.9 [6.1-102.5]), BRCA2 (p=8.4×10-10, OR [CI]: 7.0 [3.5-14.0]), and PALB2 (p=1.8×10-8, OR [CI]: 6.5 [3.2-13.1]) were strongly associated with BC. There were nominally significant associations with CHEK2, RAD51D, and TP53.

Conclusion

In H/L women, LoF variants in FANCM were strongly associated with ER-negative breast cancer risk. It previously was proposed as a possible susceptibility gene for ER-negative BC, but is not routinely tested in clinical practice. Our results demonstrate that FANCM should be added to BC gene panels.

Determinants of Obesity and Metabolic Health in the Afghan Population: Protocol, Methodology, and Preliminary Results

BACKGROUND

Non-communicable diseases (NCDs) cause more than 70% of deaths worldwide and share modifiable risk factors including obesity and metabolic abnormalities. Over the past 15 years, many changes in lifestyle, dietary patterns, physical activity, and socioeconomic status have been observed in the Afghan population. This study aims to investigate which specific lifestyle factors, dietary patterns, and characteristics of Westernization are associated with an increased risk of being overweight or obese and with poor metabolic health in the Afghan population.

METHODS

A population-based cross-sectional study was conducted where a total of 729 male and female participants were recruited. Face-to-face interviews and anthropometric measurements were conducted by trained health staff using standardized questionnaires which included information on socio-demographic and housing characteristics, income, occupation, ethnicity, personal and family medical history, stress, anthropometry, diet, and physical activity. Bioelectric impedance analysis (BIA) was used to estimate body composition, including overall body fatness. Physical activity was measured using the short version of the International Physical Activity Questionnaire (IPAQ). For a comprehensive assessment of dietary intake, a food-frequency questionnaire (FFQ) specific to the Afghan population was developed which included all local food items relevant to the population. Lipid profile and fasting glucose were measured in a local laboratory. Biospecimens were collected using dried blood spots (DBS) and dried stool cards to perform microbiome and biomarker-based research.

DISCUSSION

This is the first study which will assess dietary patterns, lifestyle factors, and their association with obesity and metabolic health in Afghanistan. Such a study will aid the development of dietary and lifestyle guidelines in Afghanistan which will promote better health and educate people to make healthy food choices. The findings will also help in designing and implementing effective public health strategies to promote a healthy lifestyle and prevent the epidemic of overweight and obesity, and, hence, reduce the burden of non-communicable diseases in the region.

Synergistic action of folate intake and testosterone associated with breast cancer risk

The amount of irreparable DNA damage is a function of the rate of cell division, and the association between sex hormones and the risk of breast cancer has been explained by an increase in cell division. Folate intake insufficiency leads to disturbances in DNA replication and DNA repair. We hypothesized that folate intake insufficiency and high serum concentrations of sex hormones act synergistically on the risk of breast cancer. The aim of this study was to investigate the interaction between sex hormones (exposure of interest A) and dietary folate intake (exposure of interest B) on the risk of breast cancer. We included 342 breast cancer primary postmenopausal cases and 294 controls obtained from a large population-based case-control study. Multiple conditional logistic regression models were used for the analysis and interactions were tested. The joint effect of the lowest dietary folate intake (T1 < 259.40 mg/d) and the highest serum concentration of testosterone (T3 ≥ 0.410 on the risk of breast cancer was odds ratio = 9.18 (95% confidence interval 2.56-32.88) when compared to the lowest-risk category, namely, the group of women with the highest dietary folate intake (T3 > 381.29 mg/d) and the lowest serum concentration of testosterone (T1 ≤ 0.25 pg/mL). There were some indications that the estimated join effect was greater than the product of the estimated effects alone (P = .001). These findings have important public health implications with respect to reducing the risk of the most frequent cancer in women worldwide.

Patterns of Alcohol Abstinence in Mexican Women Residing in the United States: Effects of Nativity and Duration in the United States

OBJECTIVES

Explore changes in abstinence rates in Mexican women (MW) residing in the United States based on nativity and time in the United States as an indicator risks for future alcohol-related disorders.

DESIGN

A secondary analysis of data from the National Health Interview Survey evaluated rates of abstinence between 2000 and 2017. A logistic regression was completed to address the impact of age, years in the United States, sample years.

SAMPLE

A total of 29,860 MW surveyed over an 18-year period that included those born in and outside the United States.

PRIMARY RESEARCH VARIABLES

Dependent variable was abstinence status; independent variables included nativity, year of survey, age, years in the United States (if immigrant).

RESULTS

Immigrant MW showed higher rates of alcohol abstinence than U.S.-born MW across all years, but regardless of place of birth, fewer MW are abstaining over time. Among immigrant MW, those only in the United States greater than 15 years had a greater risk of becoming a drinker than those in the United States less than 5 years.

CONCLUSION

There are declining rates of alcohol abstinence among MW regardless of immigration status. The lower rate of abstinent MW increases their risk for alcohol-related disorders. Assessing MW's use of alcohol and providing targeted education is essential.

Association of a Priori-Defined Dietary Patterns with Anthropometric Measurements: A Cross-Sectional Study in Mexican Women

This cross-sectional study aimed to evaluate associations between a priori defined dietary patterns and anthropometric measures in Mexican women. A total of 1062 women aged 35 to 69 years old from the control participants of the CAMA (Cancer de Mama) study, a multi-center population-based case-control study on breast cancer conducted in Mexico, were interviewed and dietary intakes were assessed using questionnaires. The following indices were derived from these data: Dietary Approaches to Stop Hypertension (DASH) score, the Healthy Eating Index (HEI), the Mediterranean Diet Score (aMED), the Diet Quality Index (DQI), glycemic index (GI) and glycemic load (GL). Adjusting for age, center, educational level, physical activity and energy intake, a high GI was positively associated with a higher body mass index (BMI) and waist circumference (WC). Higher adherence to aMED was associated with lower WC and waist-to-hip ratio (WHR) but no significant association was observed with other a priori dietary patterns. In this population of Mexican women, higher adherence to Mediterranean diet was associated with lower WC but other a priori dietary scores appeared to be of limited value in exploring the association between diet and anthropometric measures.

Características del alcoholismo en mujeres

Introducción. Durante décadas, las investigaciones sobre el alcoholismo se hicieron con muestras formadas casi exclusivamente por varones; sin embargo, el creciente interés por las necesidades de las mujeres que presentan esta problemática ha generado un aumento de los estudios sobre las diferencias de género en los trastornos por consumo de alcohol.Objetivo. Obtener una visión actualizada de las características diferenciadoras del alcoholismo en mujeres.Materiales y métodos. Revisión de la literatura en las bases de datos PsycINFO y Medline entre los años 2004 y 2014.Resultados. Los estudios revisados muestran diferencias de género en la edad de inicio del consumo, el curso clínico, los factores de riesgo, la presencia de comorbilidad psicopatológica y la demanda de tratamiento.Conclusiones. Las mujeres presentan una mayor edad de inicio del consumo de alcohol y una historia de consumo más corta hasta que desarrollan problemas. Entre los factores de riesgo de consumo se observa mayor frecuencia de acontecimientos traumáticos —como maltrato y abuso sexual infantil— y convivencia con una pareja alcohólica. Las mujeres con problemas de alcoholismo también presentan mayor prevalencia de síntomas depresivos y ansiedad y menor uso de los servicios asistenciales.

Female breast cancer in Central and South America

RATIONALE AND OBJECTIVE

The burden of breast cancer has increased worldwide. Breast cancer mortality has been increasing in Central and South America (CSA) in the last few decades. We describe the current burden of breast cancer in CSA and review the current status of disease control.

METHODS

We obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries and cancer deaths from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence and mortality rates per 100,000 person-years for 2003-2007 and the estimated annual percentage change to describe time trends.

RESULTS

In the most recent 5-year period, Argentina, Brazil, and Uruguay had the highest incidence rates (67.7-71.9) and Bolivia and El Salvador had the lowest (7.9-12.7). For most countries, mortality rates were ≤12.3, except in Uruguay, Argentina and Cuba (14.9-20.5). Age-specific rates increased after the age of 40-50 years and reached a maximum after age 65 years (mean age at diagnosis 56-62 years). Most countries have developed national screening guidelines; however, there is limited capacity for screening.

CONCLUSION

The geographic variation of breast cancer rates may be explained by differences in the prevalence of reproductive patterns, lifestyle factors, early detection, and healthcare access. Extending early-detection programs is challenging because of inequalities in healthcare access and coverage, limited funding, and inadequate infrastructure, and thus it may not be feasible. Given the current status of breast cancer in CSA, data generated by population-based cancer registries is urgently needed for effective planning for cancer control.

Cigarette Smoking and Breast Cancer Risk in Hispanic and Non-Hispanic White Women: The Breast Cancer Health Disparities Study

OBJECTIVE

Few epidemiological studies have included Hispanics with the evaluation of the effects of cigarette smoking and breast cancer. We examined the relationship between cigarette smoking, ethnicity, and breast cancer risk using data from the Breast Cancer Health Disparities Study (BCHDS).

MATERIALS AND METHODS

The BCHDS is a consortium of three population-based case-control studies, including U.S. non-Hispanic whites (NHWs) (1,525 cases; 1,593 controls), U.S. Hispanics/Native Americans (1,265 cases; 1,495 controls), and Mexican women (990 cases; 1,049 controls). Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Breast cancer risk was elevated among Mexican former smokers (OR 1.43, 95% CI 1.04-1.96) and among those who smoked ≥ 31 years (OR 1.95, 95% CI 1.13-3.35), compared to never smokers. In addition, Mexican former smokers with a history of alcohol consumption had increased breast cancer risk (OR 2.30, 95% CI 1.01-5.21). Among NHW premenopausal women, breast cancer risk was increased for smoking ≥ 20 cigarettes per day (OR 1.61, 95% CI 1.07-2.41).

CONCLUSION

Our findings suggest the possibility of ethnic differences with the associations between cigarette smoking and breast cancer risk.

Adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations and breast cancer risk in the Cancer de Màma (CAMA) study

OBJECTIVE

We investigated the association between adherence to the recommendations of the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and breast cancer (BC) risk in the Cancer de Màma (CAMA) study in a Mexican population.

DESIGN

Population-based case-control study.

SUBJECTS

Incident BC cases (n 1000) and controls (n 1074) matched on age, region and health-care system were recruited.

SETTING

In-person interviews were conducted to assess BC risk factors and habitual diet was assessed with an FFQ. Conformity to the WCRF/AICR recommendations was evaluated through a score incorporating seven WCRF/AICR components (body fatness, physical activity, foods and drinks that promote weight gain, plant foods, animal foods, alcoholic drinks and breast-feeding), with high scores indicating adherence to the WCRF/AICR recommendations.

RESULTS

No statistically significant associations between WCRF/AICR score and risk of BC were observed. After excluding BMI from the WCRF/AICR score, the top quartile was associated with a decreased BC risk overall, with ORQ4-Q1=0.68 (95% CI 0.49, 0.92, P trend=0.03), and among postmenopausal women, with ORQ4-Q1=0.60 (95% CI 0.39, 0.94, P trend=0.03). Inverse associations were observed between BMI and risk of BC overall and among premenopausal women, with OR=0.57 (95% CI 0.42, 0.76, P trend <0.01) and 0.48 (95% CI 0.31, 0.73, P trend<0.01), respectively. Physical activity level was inversely associated with BC risk.

CONCLUSIONS

The WCRF/AICR index was not related with BC risk in the CAMA study. A combination of six components excluding BMI showed strong protective associations, particularly in postmenopausal women. Further prospective studies are required to clarify the role of adherence to WCRF/AICR recommendations, particularly with respect to BMI, in the Mexican population.

Relation of alcohol/tobacco use with metastasis, hormonal (estrogen and progesterone) receptor status and c-erbB2 protein in mammary ductal carcinoma

BACKGROUND

An association between alcohol/tobacco use and risk of metastasis in breast cancer has been clearly shown.

MATERIALS AND METHODS

The present study explored, in 48 samples of tissue from mammary ductal carcinoma (taken from Mexican women with an average age of 58.2±10.9 years), the association of risk of metastasis with the status of hormonal receptors and the c-erbB2 protein (by immunohistochemistry) as well as clinical, histopathological and sociodemographic factors.

RESULTS

Of 48 patients, 41.6% (20/48) presented with metastasis, 43.8% were positive for the estrogen receptor (RE+), 31.3% for the progesterone receptor (RP+) and 47.7% for c-erbB2 (c-erbB2+). The following combinations were found: RE+/RP+/c-erbB2+ 8.3%, RE+/RP+ 22.9%, RE+/RP- 20.8%, RE-/RP+ 8.3%, RE-/RP-/c-erbB2- 22.9% and RE-/RP- 47.8%. There were 12 patients who used alcohol/tobacco, of which 91.6% did not present metastasis and 81.9% were RE-/RP-. Compared to the RE-/RP-/c-erbB2+, the RE+/RP+/c-erbB2+ group had a 15-fold greater risk for metastasis (95%CI, 0.9-228.8, p=0.05). The carriers of the double negative hormonal receptors had a 4.7 fold greater probability of being (or having been) smokers or drinkers (95%CI, 1.0-20.4, p = 0.03).

CONCLUSIONS

There was a clear protective effect of using alcohol and/or tobacco, in the cases included in the present study of mammary ductal carcinoma, associated with double negative hormonal receptors. However, this association could be due to a protective factor not measured (Neyman bias) or to a bias inherent in the rate of hospitalization (Berkson fallacy). This question should be explored in a broad prospective longitudinal study.

Recurrent BRCA1 and BRCA2 mutations in Mexican women with breast cancer

BACKGROUND

Germline mutations in the BRCA1 and BRCA2 genes confer an estimated 58% to 80% lifetime risk of breast cancer. In general, screening is done for cancer patients if a relative has been diagnosed with breast or ovarian cancer. There are few data on the prevalence of mutations in these genes in Mexican women with breast cancer and this hampers efforts to develop screening policies in Mexico.

METHODS

We screened 810 unselected women with breast cancer from three cities in Mexico (Mexico City, Veracruz, and Monterrey) for mutations in BRCA1 and BRCA2, including a panel of 26 previously reported mutations.

RESULTS

Thirty-five mutations were identified in 34 women (4.3% of total) including 20 BRCA1 mutations and 15 BRCA2 mutations. Twenty-two of the 35 mutations were recurrent mutations (62.8%). Only five of the 34 mutation carriers had a first-degree relative with breast cancer (three with BRCA1 and two with BRCA2 mutations).

CONCLUSION

These results support the rationale for a strategy of screening for recurrent mutations in all women with breast cancer in Mexico, as opposed to restricting screening to those with a sister or mother with breast or ovarian cancer.

IMPACT

These results will impact cancer genetic testing in Mexico and the identification of at-risk individuals who will benefit from increased surveillance. Cancer Epidemiol Biomarkers Prev; 24(3); 498-505. ©2014 AACR.

MAPK genes interact with diet and lifestyle factors to alter risk of breast cancer: the Breast Cancer Health Disparities Study

Mitogen-activated protein kinases (MAPK) are integration points for multiple biochemical signals. We evaluated 13 MAPK genes with breast cancer risk and determined if diet and lifestyle factors mediated risk. Data from 3 population-based case-control studies conducted in Southwestern United States, California, and Mexico included 4183 controls and 3592 cases. Percent Indigenous American (IA) ancestry was determined from 104 ancestry informative markers. The adaptive rank truncated product (ARTP) was used to determine the significance of each gene and the pathway with breast cancer risk, by menopausal status, genetic ancestry level, and estrogen receptor (ER)/progesterone receptor (PR) strata. MAP3K9 was associated with breast cancer overall (P(ARTP) = 0.02) with strongest association among women with the highest IA ancestry (P(ARTP) = 0.04). Several SNPs in MAP3K9 were associated with ER+/PR+ tumors and interacted with dietary oxidative balance score (DOBS), dietary folate, body mass index (BMI), alcohol consumption, cigarette smoking, and a history of diabetes. DUSP4 and MAPK8 interacted with calories to alter breast cancer risk; MAPK1 interacted with DOBS, dietary fiber, folate, and BMI; MAP3K2 interacted with dietary fat; and MAPK14 interacted with dietary folate and BMI. The patterns of association across diet and lifestyle factors with similar biological properties for the same SNPs within genes provide support for associations.

Alcohol and breast cancer: reconciling epidemiological and molecular data

Breast cancer is the most diagnosed cancer in women worldwide. Epidemiological studies have suggested a possible causative role of alcohol consumption as a risk factor for breast cancer. However, such conclusions should be interpreted with considerable caution for several reasons. While epidemiological studies can help identify the roots of health problems and disease incidence in a community, they are by necessity associative and cannot determine cause and effect relationships. In addition, all these studies rely on self-reporting to determine the amount and type of alcoholic beverage consumed, which introduces recall bias. This is documented in a recent study which stated that the apparent increased risk of cancer among light-moderate drinkers may be "substantially due to underreporting of intake." Another meta-analysis about alcohol and breast cancer declared "the modest size of the association and variation in results across studies leave the causal role of alcohol in question." Furthermore, breast cancer develops over decades; thus, correlations between alcohol consumption and breast cancer cannot be determined in epidemiological studies with windows of alcohol exposure that captures current or recent alcohol intake, after clinical diagnosis. Numerous risk factors are involved in breast carcinogenesis; some are genetic and beyond the control of a woman; others are influenced by lifestyle factors. Breast cancer is a heterogeneous and polygenic disease which is further influenced by epigenetic mechanisms that affect the transciptomes, proteomes and metabolomes, and ultimately breast cancer evolution. Environmental factors add another layer of complexity by their interactions with the susceptibility genes for breast cancer and metabolic diseases. The current state-of-knowledge about alcohol and breast cancer association is ambiguous and confusing to both a woman and her physician. Confronting the huge global breast cancer issue should be addressed by sound science. It is advised that women with or without a high risk for breast cancer should avoid overconsumption of alcohol and should consult with their physician about risk factors involved in breast cancer. Since studies associating moderate alcohol consumption and breast cancer are contradictory, a woman and her physician should weigh the risks and benefits of moderate alcohol consumption.

Association of xeroderma pigmentosum complementation group G Asp1104His polymorphism with breast cancer risk: A cumulative meta-analysis

The xeroderma pigmentosum complementation group G (XPG) gene plays an important role in the DNA nucleotide excision repair (NER) pathway. Several studies have investigated the association between the XPG Asp1104His polymorphism and breast cancer; however, the results have been inconsistent. Therefore, we conducted a meta-analysis of 8 published articles (10 case-control studies) including a total of 5,235 patients with breast cancer and 5,685 healthy controls. The results demonstrated that the XPG Asp1104His polymorphism was not associated with breast cancer in the overall population [His vs. Asp, odds ratio (OR)=1.00, 95% confidence interval (CI): 0.91-1.08; His/His vs. Asp/Asp, OR=0.96, 95% CI: 0.83-1.11; Asp/His vs. Asp/Asp, OR=1.02, 95% CI: 0.94-1.11; His/His+Asp/His vs. Asp/Asp, OR=1.03, 95% CI: 0.92-1.15; and His/His vs. Asp/Asp+Asp/His, OR=0.93, 95% CI: 0.81-1.06]. In the subgroup analysis by ethnicity, no significant association was observed in European subjects. In conclusion, this meta-analysis suggested that the XPG Asp1104His polymorphism is not associated with breast cancer risk.

Higher dietary folate intake reduces the breast cancer risk: a systematic review and meta-analysis

Background:

Many epidemiological studies have investigated the association between folate intake, circulating folate level and risk of breast cancer; however, the findings were inconsistent between the studies.

Methods:

We searched the PubMed and MEDLINE databases updated to January, 2014 and performed the systematic review and meta-analysis of the published epidemiological studies to assess the associations between folate intake level, circulating folate level and the overall risk of breast cancer.

Results:

In all, 16 eligible prospective studies with a total of 744 068 participants and 26 205 breast cancer patients and 26 case–control studies with a total of 16 826 cases and 21 820 controls that have evaluated the association between folate intake and breast cancer risk were identified. Pooled analysis of the prospective studies and case–control studies suggested a potential nonlinearity relationship for dietary folate intake and breast cancer risk. Prospective studies indicated a U-shaped relationship for the dietary folate intake and breast cancer risk. Women with daily dietary folate intake between 153 and 400 μg showed a significant reduced breast cancer risk compared with those <153 μg, but not for those >400 μg. The case–control studies also suggested a significantly negative correlation between the dietary folate intake level and the breast cancer risk. Increased dietary folate intake reduced breast cancer risk for women with higher alcohol intake level, but not for those with lower alcohol intake. No significant association between circulating folate level and breast cancer risk was found when the results of 8 identified studies with 5924 participants were pooled.

Conclusions:

Our studies suggested that folate may have preventive effects against breast cancer risk, especially for those with higher alcohol consumption level; however, the dose and timing are critical and more studies are warranted to further elucidate the questions.

Anthropometry, silhouette trajectory, and risk of breast cancer in Mexican women

BACKGROUND

Obesity has been associated with breast cancer risk in the Caucasian population but the association remains unclear in the Hispanics. Previous studies conducted among Hispanics in the U.S. have shown inconsistent results.

PURPOSE

The association between anthropometry, body shape evolution across lifetime, and the risk of breast cancer was assessed using a multi-center population-based case-control study conducted in Mexico.

METHODS

One thousand incident cases and 1074 matched control women aged 35-69 years were recruited between 2004 and 2007, and analyzed in 2011-2012. Conditional logistic regression models were used.

RESULTS

Height was related to an increased risk of breast cancer in both premenopausal (p trend=0.03) and postmenopausal women (p trend=0.002). In premenopausal women, increase in BMI; waist circumference (WC); hip circumference (HC); and waist-hip ratio (WHR) were inversely associated with breast cancer risk (p trends<0.001 for BMI and WC, 0.003 for HC, and 0.016 for WHR). In postmenopausal women, decreased risks were observed for increased WC (p trend=0.004) and HC (p trend=0.009) among women with time since menopause <10 years. Further analysis of body shape evolution throughout life showed strong and significant increase in risk of breast cancer among women with increasing silhouettes size over time compared to women with no or limited increase.

CONCLUSIONS

These findings suggest that anthropometric factors may have different associations with breast cancer risk in Hispanic women than in Caucasian women. This study also shows the importance of considering the evolution of body shape throughout life.

Hormonal therapy and risk of breast cancer in mexican women

The use of hormonal therapies, including hormonal contraceptives (HC) and postmenopausal hormone replacement therapy (HRT) have been shown to influence breast cancer (BC) risk. However, the variations of these effects among populations and ethnic groups are not completely documented, especially among Hispanic women. We evaluated the association between HC and premenopausal BC risk, and between HRT and postmenopausal BC risk in Mexican women. Data from a Mexican multi-center population-based case–control study ofwomen aged 35 to 69 years were analysed. A total of 1000 cases and 1074 matched controls were recruited between 2004 and 2007. Information on hormonal therapy was collected through a structured questionnaire. Results were analysed using conditional logistic regression models. Overall, HC were used by 422/891 (47.3%) premenopausal women and HRT was used by 220/1117 (19.7%) postmenopausal women. For HC, odds ratios (ORs) for BC were 1.11 (95% confidence interval (CI): 0.82, 1.49) for current users and 1.68 (95% CI: 0.67, 4.21) for ever-users. No clear effect of duration of use was observed. For HRT, the OR for BC was significantly increased in ever users (OR: 1.45; 95% CI: 1.01, 2.08). A non-significant increased risk was observed for combined estrogen/progestin, (OR =  1.85; 95% CI: 0.84, 4.07) whereas no effect was observed for the use of estrogen alone (OR = 1.14; 95% CI: 0.68, 1.91). Our results indicate that, HC had a non-significant effect on the risk of pre-menopausal BC, but suggested that injected contraceptives may slightly increase the risk, whereas HRT had a significant effect on post-menopausal BC in this population. This study provides new information about the effects of HC and HRT on BC risk in a Mexican population, which may be of relevance for the population of Latin America as a whole.

Association between rs2981582 polymorphism in the FGFR2 gene and the risk of breast cancer in Mexican women

BACKGROUND AND AIMS

The rs2981582 single nucleotide polymorphism in the fibroblast growth factor receptor 2 gene has been consistently associated with an increased risk of breast cancer. We evaluated the effect of rs2981582 polymorphism in the FGFR2 gene on the risk of breast cancer and its interaction with non-genetic risk factors.

METHODS

A population-based case-control study was conducted in Mexico. Data from 687 cases and 907 controls were analyzed.

RESULTS

The T allele of the rs2981582 polymorphism was associated with an increased risk of breast cancer (ORper allele = 1.24, 95% CI 1.06-1.46). There was also an interaction between this polymorphism and alcohol consumption (p = 0.043). The effect of alcohol consumption on the risk of breast cancer varied according to the allelic variants of the rs2981582 polymorphism in the FGFR2 gene: OR = 3.97 (95% CI 2.10-7.49), OR = 2.01 (95% CI 1.23-3.29) and OR = 1.21 (95% CI 0.48-3.05) for genotypes CC, CT and TT, respectively.

CONCLUSIONS

This is the first study exploring the association between rs2981582 polymorphism in the FGFR2 gene and breast cancer risk in Mexican women. The interaction found may be of great public health interest because alcohol consumption is a modifiable breast cancer risk factor. Therefore, replication of this finding is of foremost importance.

Breast cancer in the Arctic--changes over the past decades

The purpose of this study is to review the current literatures on breast cancer (BC) in the Arctic, especially the trends in incidence during the last decades and the possible explanations. The design of this study is a literature review. The scientific literature concerning BC were reviewed, especially focusing on the Arctic and the special conditions that exist in this region. Breast cancer incidence is increasing all over the world, including in the Arctic. The enormous transition in health conditions and lifestyle in the Arctic might be contributing to the known risk factors. In Greenland, the age at menarche has diminished by 3 years during the course of 100 years, and the number of children per women as well as the duration of breastfeeding is decreasing. Obesity and intake of saturated fat is increasing and the intake of traditional food rich in unsaturated fat and vitamin D decreasing. Smoking and alcohol consumption in the Arctic has been relatively high but is now decreasing. More focus on genetic susceptibility in relation to BC has identified the specific BRCA1 founder mutation in the Greenlandic population, which might appear to be an important risk factor. However, the known established risk factors alone cannot account for the increasing trend observed. Studies suggest that environmental contaminants such as persistent organic pollutants (POPs) including perfluorinated compounds increase the risk of BC possibly in conjunction with certain genetic polymorphisms involved in carcinogen activation. The lipophilic POPs such as polychlorinated biphenyls and organochlorine pesticides are found at very high levels in the Arctic population. Several factors can explain the increasing incidence of BC in the Arctic. The transition in lifestyle and health conditions unfortunately increases the known risk factors of BC. Moreover, the population of the Arctic might show up to be especially vulnerable because of the contemporary high burden of POPs and genetic susceptibility.

Serum 25-hydroxyvitamin D and risk of breast cancer: results of a large population-based case-control study in Mexican women

PURPOSE

Epidemiologic studies have suggested that higher levels of circulating vitamin D may reduce breast cancer risk, but no studies have investigated this association among women in developing countries, and very few studies have further investigated this association according to menopausal status.

METHODS

A population-based case-control study in Mexico with 1,000 incident breast cancer cases aged 35-69 years, enrolled shortly after diagnosis (0-6 days) and frequency-matched to 1,074 controls on age, region, and health care system, was used to assess the association between serum 25-hydroxyvitamin D [25(OH)D] levels with overall, pre- and postmenopausal breast cancer risk. 25(OH)D concentration was measured on a random sub-sample of women (573 cases and 639 matched controls) using a liquid chromatography/tandem mass spectrometry method. Odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated from multivariable conditional logistic regression models.

RESULTS

Serum 25(OH)D concentration (per 10 ng/mL increase) showed a strong inverse association with risk of breast cancer among all (p(trend) = 0.001), pre- (p(trend) = 0.006) and postmenopausal women (p(trend) = 0.0001). Compared with a predefined lower concentration of 25(OH)D (<20 ng/mL), higher levels (>30 ng/mL) were associated with lower overall (OR = 0.53, 95 % CI: 0.28-1.00; p(trend) = 0.002), pre- (OR = 0.60, 95 % CI: 0.16-2.17; p(trend) = 0.07) and postmenopausal (OR = 0.37, 95 % CI: 0.16-0.82; p(trend) = 0.004) breast cancer risk.

CONCLUSIONS

The results of this large population-based case-control study indicate an inverse association between circulating vitamin D levels and breast cancer risk among pre- and postmenopausal Mexican women.

ω-3 and ω-6 Polyunsaturated fatty acid intakes and the risk of breast cancer in Mexican women: impact of obesity status

BACKGROUND

ω-3 polyunsaturated fatty acids (PUFA) could play a protective role on the risk of breast cancer; however, little is known about this relation among Mexican women. We evaluated the association between ω-3 and ω-6 PUFA intake and breast cancer risk by obesity status in Mexican women.

METHODS

A population-based case-control study was conducted in Mexico, including 1,000 incident breast cancer cases and 1,074 controls matched to cases by age, health care system, and region. Women provided information on health and diet by in-person interview. Body mass index (BMI) measures were used to define overall obesity. Obesity status was categorized as normal weight (18.5 < BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). A conditional logistic regression model was used to assess the association between PUFA and breast cancer risk.

RESULTS

Overall, there was no significant association between ω-3 PUFA intake and breast cancer risk (P = 0.31). An increased risk of breast cancer was associated with increasing ω-6 PUFA intake in premenopausal women [OR = 1.92, 95% confidence interval (CI) = 1.13-3.26; P = 0.04]. A decreased risk of breast cancer was significantly associated with increasing ω-3 PUFA intake in obese women (OR = 0.58, 95% CI = 0.39-0.87; P = 0.008) but not in normal weight nor in overweight women (P(heterogeneity) = 0.017).

CONCLUSIONS

Obesity status may affect the association between ω-3 PUFA intake and breast cancer risk. The underlying mechanisms may be related to decreased inflammation and improved adipokin and estrogen levels induced by ω-3 PUFA in adipose tissue in obese women.

IMPACT

Increased intake of ω-3 PUFA should be recommended among Mexican women in particular in obese women.

Low-to-moderate alcohol intake and breast cancer risk in Chinese women

BACKGROUND

Despite extensive investigation of the association between alcohol consumption and breast cancer risk, effect of low-to-moderate alcohol intake on breast cancer incidence has been inconsistent.

METHODS

A case-control study was conducted in China, 2004-2005 to examine the association by menopausal status, oestrogen (ER) and progesterone receptor (PR) status of the tumour. There were 1009 incident cases with histologically confirmed breast cancer and 1009 age-matched controls recruited. We assessed alcohol consumption by face-to-face interview using a validated questionnaire and obtained tumour ER and PR status from pathology reports.

RESULTS

Low-to-moderate alcohol consumption was inversely associated with breast cancer risk. Compared with nondrinkers, the adjusted odds ratios (ORs) for alcohol <5 g per day were 0.41 (95% confidence interval 0.27-0.62) and 0.62 (0.48-0.79) in postmenopausal and premenopausal women, respectively. The inverse association was consistent for alcohol <15 g per day across hormone receptor status groups with ORs of 0.36-0.56 in postmenopausal women and 0.57-0.64 in premenopausal women. An exception was that alcohol ≥15 g per day appeared to increase the risk of breast cancers with discordant receptor status in postmenopausal women, that is, ER+/PR- or ER-/PR+ (4.27, 1.57-11.65).

CONCLUSION

We found that low-to-moderate alcohol intake was not associated with increased risk of breast cancer in pre- or postmenopausal Chinese women. Future studies are required to understand differences in effect of alcohol on breast cancers by tumour hormone receptor status.

Healthy lifestyle on the risk of breast cancer

BACKGROUND

Many studies have analyzed the effect of behavioral risk factors such as common lifestyle patterns on the risk of disease. The aim of this study was to assess the effect of a healthy lifestyle index on the risk of breast cancer.

METHODS

A population-based case-control study was conducted in Mexico from 2004 to 2007. One thousand incident cases and 1,074 controls, matched to cases by 5-year age category, region, and health institution, participated in the study. A healthy lifestyle index was developed by means of principal components by using dietary pattern, physical activity, alcohol consumption, and tobacco smoking. A conditional logistic regression model was used to assess this association.

RESULTS

The healthy lifestyle index was defined as the combined effect of moderate and/or vigorous-intensity physical activity, low consumption of fat, processed foods, refined cereals, complex sugars, and the avoidance of tobacco smoking and alcohol consumption. Results showed a protective effect on both pre- (OR = 0.50, 95% CI: 0.29-0.84) and postmenopausal women (OR = O.20, 95% CI: 0.11-0.37) when highest versus lowest index quintiles were compared.

CONCLUSIONS

Healthy lifestyle was associated with a reduction in the odds of having breast cancer. Primary prevention of this disease should be promoted in an integrated manner. Effective strategies need to be identified to engage women in healthy lifestyles.

IMPACT

This study is the first to assess a healthy lifestyle index in relation to the risk of breast cancer.