Weight Fluctuation and Cancer Risk in Postmenopausal Women: The Women's Health Initiative

Weight-cycling over 6 years is associated with pain, physical function and depression in the Osteoarthritis Initiative cohort

Body weight significantly impacts health and quality of life, and is a leading risk factor for the development of knee osteoarthritis (OA). Weight cycling may have more negative health consequences compared to steady high or low weight. Using the Osteoarthritis Initiative dataset, we investigated the effects of weight cycling on physical function, quality of life, and depression over 72-months compared to stable or unidirectional body weight trajectories. Participants (n = 731) had knee OA and were classified as: (1) stable-low (BMI < 25), (2) stable-overweight (BMI = 25-29.9), and (3) stable-obese (BMI ≥ 30); (4) steady-weight-loss; (5) steady-weight-gain (weight loss/gain ≥ 2.2 kg every 2-years); (6) gain-loss-gain weight cycling, and (7) loss-gain-loss weight cycling (weight loss/gain with return to baseline), based on bi-annual assessments. We compared Knee Injury and Osteoarthritis Outcome Knee-Related Quality of Life, Function in Sports and Recreation, Physical Activity in the Elderly, Short Form SF-12, repeated chair rise, 20-m gait speed, and Center for Epidemiological Studies Depression using repeated-measures ANOVA. The steady weight loss group demonstrated the worst pain, physical function, and depressive symptoms over time (p's < 0.05). More research is needed to confirm these findings, and elucidate the mechanisms by which steady weight loss is associated with functional decline in knee OA.

Body size over the adult life course and the risk of colorectal cancer among postmenopausal women

OBJECTIVE

To assess the associations among several anthropometric measures, as well as BMI trajectories and colorectal cancer (CRC) risk in older women.

DESIGN

Prospective cohort study.

SETTING

Forty clinical centres in the USA.

PARTICIPANTS

Totally, 79 034 postmenopausal women in the Women's Health Initiative Observational Study.

RESULTS

During an average of 15·8 years of follow-up, 1514 CRC cases were ascertained. Five BMI trajectories over 18-50 years of age were identified using growth mixture model. Compared with women who had a normal BMI at age 18, women with obesity at age 18 had a higher risk of CRC (HR 1·58, 95 % CI 1·02, 2·44). Compared with women who kept relatively low normal body size during adulthood, women who progressed from normal to obesity (HR 1·29, 95 % CI 1·09, 1·53) and women who progressed from overweight to obesity (HR 1·37, 95 % CI 1·13, 1·68) had higher CRC risks. A weight gain > 15 kg from age 18 to 50 (HR 1·20, 95 % CI 1·04, 1·40) and baseline waist circumference > 88 cm (HR 1·33, 95 % CI 1·19, 1·49) were associated with higher CRC risks, compared with stable weight and waist circumference ≤ 88 cm, respectively.

CONCLUSION

Women who have a normal weight in early adult life and gain substantial weight later, as well as those who are persistently heavy over adulthood, demonstrated a higher risk of developing CRC. Our study highlights the importance of maintaining a healthy body weight over the life course for reducing the risk of developing CRC in women.

Investigating the efficacy and feasibility of using a whole-of-diet approach to lower circulating levels of C-reactive protein in postmenopausal women: a mixed methods pilot study

OBJECTIVE

Chronic inflammation is associated with obesity and is an underlying pathophysiology for cardiovascular disease (CVD) development in postmenopausal women. This study aims to determine feasibility and efficacy of an anti-inflammatory dietary intervention to lower levels of C-reactive protein in weight stable postmenopausal women with abdominal obesity.

METHODS

This mixed-methods pilot study used a single arm pre-post design. Thirteen women followed a 4-week anti-inflammatory, dietary intervention, optimizing consumption of healthy fats, low glycemic index wholegrains, and dietary antioxidants. Quantitative outcomes included change in inflammatory and metabolic markers. Focus groups were undertaken and thematically analyzed to explore participants lived experience of following the diet.

RESULTS

There was no significant change in plasma high-sensitivity C-reactive, protein. Despite discouraging weight loss, median (Q1-Q3) body weight decreased by -0.7 (-1.3 to 0 kg, P = 0.02). This was accompanied by reductions in plasma insulin (0.90 [-0.05 to 2.20] mmol/L), Homeostatic Model Assessment of Insulin Resistance (0.29 [-0.03 to 0.59]), and low-density lipoprotein:high-density lipoprotein ratio (0.18 [-0.01 to 0.40]) ( P ≤ 0.023 for all). Thematic analysis revealed that postmenopausal women have a desire to improve meaningful markers of health status that do not focus on weight. Women were highly engaged with learning about emerging and innovative nutrition topics, favoring a detailed and comprehensive nutrition education style that challenged their proficient health literacy and cooking skills.

CONCLUSIONS

Weight-neutral dietary interventions targeting inflammation can improve metabolic markers and may be a viable strategy for CVD risk reduction in postmenopausal women. To determine effects on inflammatory status, a fully powered and longer-term randomized controlled trial is required.

The Association Between Nutrition, Obesity, Inflammation, and Endometrial Cancer: A Scoping Review

PURPOSE OF REVIEW

Endometrial cancer is the most common gynecological malignancy and represents a notorious threat to women's health worldwide. Endometrial cancer predominantly affects post-menopausal women; yet the prevalence of this disease has been rising also among pre-menopausal women. Poor nutritional habits, inflammation, and obesity may be associated with endometrial cancer (EC) among both pre-menopausal and post-menopausal women and should be further assessed among a wide spectrum of age groups.

RECENT FINDINGS

This scoping review explores and reports on primary research studies conducted to investigate the impact of nutrition, inflammation, and/or obesity on endometrial cancer risk among both pre-menopausal and post-menopausal women. Using a predefined protocol in compliance with the PRISMA guidelines, a search was conducted on four separate databases including PubMed, Cochrane Library, ProQuest, and Google Scholar to investigate the association between nutrition, inflammation, obesity, and endometrial cancer. A total of 4862 articles were identified. Following a full article analysis, 27 articles met the full inclusion criteria and were included in the current review. Findings from the literature support a role of nutrition, obesity, and inflammation in the development of EC. The studies included in the current review supported that plant-based, Mediterranean, or ketogenic diets are associated with a lower risk of EC while there is no association between glycemic index and EC risk. On the other hand, increased BMI is associated with a higher risk of EC and there is a positive association between obesity-related pro-inflammatory biomarkers and increased risk for EC development. Further research needs to be conducted to gain more insight into the complex interactions between nutrition, obesity, and inflammation and their association with EC development among pre-, peri-, and post- menopausal women with the ultimate goal to improve management and preventive strategies and achieve reduced prevalence of endometrial cancer.

Obesity and Breast Cancer Risk: The Oncogenic Implications of Metabolic Dysregulation

CONTEXT

Breast cancer is increasing in prevalence in parallel with rising rates of obesity worldwide. Obesity is recognized as a leading modifiable risk factor for the development of breast cancer; however, this association varies considerably by clinicopathologic features, and the underlying mechanisms are complex.

EVIDENCE ACQUISITION

Pubmed literature search using combinations of "obesity," "breast cancer risk," "diet," "exercise," "weight gain," "weight loss," "adipose tissue inflammation," "crown-like structure," "immune markers," "metformin," "gliflozins," "SGLT-2i," "GLP1-RA," and related terms.

EVIDENCE SYNTHESIS

Elevated body mass index and weight gain are associated with increased risk of postmenopausal, hormone receptor-positive breast cancer. Emerging evidence suggests that adverse measures of body composition in individuals of any weight can also confer increased breast cancer risk. Mechanistically, various factors including altered adipokine balance, dysfunctional adipose tissue, dysregulated insulin signaling, and chronic inflammation contribute to tumorigenesis. Weight loss and more specifically fat mass loss through lifestyle and pharmacologic interventions improve serum metabolic and inflammatory markers, sex hormone levels, and measures of breast density, suggesting a link to decreased breast cancer risk.

CONCLUSION

Incorporating markers of metabolic health and body composition measures with body mass index can capture breast cancer risk more comprehensively. Further studies of interventions targeting body fat levels are needed to curb the growing prevalence of obesity-related cancer.

Consecutive gain and loss in body weight and waist circumference with risk of subsequent breast cancer in Korean women

BACKGROUND

This study investigated the association between longitudinal changes in weight and waist circumference and breast cancer risk according to menopausal status.

METHODS

This retrospective cohort study used data from the population-based Korean National Health Insurance Service (NHI) database. The study population included women aged ≥40 years who consecutively underwent three biennial breast cancer screenings between 2009-2014 and were followed up until 2020. The percentage changes in weight and waist circumference during the three screenings were calculated and categorized into five groups based on the level of increase or decrease in these two factors. Hazard ratios (HRs) and 95% confidence intervals (95% CI) for breast cancer risk were calculated and adjusted for other factors.

RESULTS

Of 691,253 premenopausal and 1,519,211 postmenopausal women, 9485 and 12,553 breast cancer cases were identified, respectively, during a median 6.9 follow-up years. Postmenopausal women with two consecutive weight gains had an increased risk of breast cancer risk (HR = 1.11, 95% CI = 1.01 to 1.22); meanwhile, consecutive weight loss was associated with a decreased risk (HR = 0.84, 95% CI = 0.76 to 0.93). Single time and continuous decreases in waist circumference were associated with a decreased risk (HR = 0.91, 95% CI = 0.85 to 0.98, and HR = 0.84, 95% CI = 0.76-0.93), while single time and continuous increases were associated with an increased risk (HR = 1.08, 95% CI = 1.01 to 1.15, and HR = 1.13, 95% CI = 1.04 to 1.22). Single weight gain was associated with the increased breast cancer risk in premenopausal women (HR = 1.07, 95% CI = 1.01 1.13).

CONCLUSIONS

Our findings suggest a dose-response relationship between weight, waist circumference change, and the risk of future breast cancer.

Weight-change trajectory in relation to cancer risk: findings from a nationwide cohort study in South Korea

OBJECTIVE

This study examined relationships between weight-change trajectories and all cancers and obesity-related cancer risks.

METHODS

A total of 1,882,304 men and 899,912 women from the 2002 to 2017 National Health Insurance Service cohort were included. Weight-change trajectories in 2002 to 2009, according to BMI, were determined using group-based trajectory modeling. Cox proportional hazards regression assessed associations between trajectories and cancer incidence.

RESULTS

Overall, >50% of individuals maintained stable weight, as did two-thirds of those in the overweight and obesity groups. A total of 64,725 men and 37,608 women developed incident cancer. Weight stability in overweight or obesity groups was associated with greater cancer risk. In both sexes, higher weight across BMI groups increased risks of all cancers, obesity-related cancers and thyroid, colorectal, stomach, liver, prostate, and postmenopausal breast cancer. Stratified by BMI, weight gain increased risks of all cancers and obesity-related cancers in men with obesity class I and women with overweight. Weight loss decreased risks of obesity-related cancers, thyroid cancer, and kidney cancer among men with overweight, premenopausal breast, endometrial, and ovarian cancer in women with overweight, and obesity-related cancers and thyroid cancer in women with class I obesity.

CONCLUSIONS

Maintaining weight and avoiding weight gain are crucial for reducing cancer risk, but achieving a stable, normal BMI optimizes cancer prevention.

Dynamic physical examination indicators of cardiovascular health: A single-center study in Shanghai, China

Dynamic physical examination data can provide both cross-sectional and time-series characteristics of cardiovascular health. However, most physical examination databases containing health and disease information have not been fully utilized in China. Hence, this study aimed to analyze dynamic physical examination indicators for cardiovascular health to provide evidence for precise prevention and control of cardiovascular diseases in the primary prevention domain among healthy population with different demographic characteristics in Shanghai. Three-year continuous data were collected from the physical examination center of a hospital in Shanghai from 2018 to 2020, which included a total of 14,044 participants with an average age of 46.51±15.57 years. The cardiovascular status of overall healthy individuals may have a decreasing trend, which is manifested as a significant year-on-year decrease in high-density lipoprotein cholesterol; a significant year-on-year increase in total cholesterol, low-density lipoprotein cholesterol, and blood glucose levels; and a possible increasing trend of diastolic blood pressure, body mass index, and triglycerides. Healthy population with different sex and age groups have various sensitives to cardiovascular physical examination indicators. To conduct more accurate cardiovascular health management and health promotion for key populations in primary prevention, focusing on the dynamic trends of blood pressure, blood lipids, blood glucose, and body mass index in men and changes in total cholesterol in women over time is especially important. The age group of 50–69 years is key for better prevention and control of cardiovascular health.

Sustained Weight Loss, Weight Cycling, and Weight Gain During Adulthood and Pancreatic Cancer Incidence in the Women's Health Initiative

Pancreatic cancer (PC) is the fourth leading cause of cancer mortality among women in the United States. Obesity is positively associated with PC risk. Current health recommendations focus on weight maintenance for healthy-weight individuals and weight loss for overweight/obese individuals; however, little research has assessed associations between PC risk and changes in weight throughout the life course. Using prospective cohort study data, we examined the relationship between baseline adulthood weight patterns self-reported between 1993 and 1998 and PC risk in 136,834 postmenopausal women with 873 incident PC cases through September 30, 2015, in the Women's Health Initiative. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models, adjusting for age, smoking habits, heavy alcohol consumption, and body mass index. Compared with women with stable weight, no significant associations were found between steady weight gain (HR = 1.01, 95% CI: 0.83, 1.22), sustained weight loss (HR = 1.26, 95% CI: 0.85, 1.87), or weight cycling patterns (HR = 1.08, 95% CI: 0.89, 1.30) and PC. Results were similar when the outcome definition was restricted to pancreatic adenocarcinoma cases. Overall, we did not find evidence to suggest that weight changes in adulthood significantly impact PC risk among postmenopausal women.

Maximum and Time-Dependent Body Mass Index and Breast Cancer Incidence Among Postmenopausal Women in the Black Women's Health Study

While excess weight is an established risk factor for postmenopausal breast cancer, consideration of maximum body mass index (maxBMI; BMI is calculated as weight (kg)/height (m)2) or BMI at a point in time relevant for breast carcinogenesis may offer new insights. We prospectively evaluated maxBMI and time-dependent BMI in relation to breast cancer incidence among 31,028 postmenopausal women in the Black Women's Health Study. During 1995-2015, a total of 1,384 diagnoses occurred, including 787 estrogen-receptor (ER)-positive (ER+) cases and 310 ER-negative (ER-) cases. BMI was assessed at baseline and 2, 4, 6, and 8 years before diagnosis. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Compared with women with BMI <25, those with BMI ≥35 had increased risk of ER+ breast cancer but not ER- breast cancer. For BMI assessed 2 years before diagnosis, the HRs for ER+ breast cancer associated with maxBMI ≥35 and time-dependent BMI ≥35 were 1.42 (95% confidence interval (CI): 1.10, 1.84) and 1.63 (95% CI: 1.25, 2.13), respectively. The corresponding HR for time-dependent BMI assessed 6 years before diagnosis was 1.95 (95% CI: 1.45, 2.62). These findings suggest strong associations of BMI with risk of ER+ breast cancer in postmenopausal women, regardless of timing of BMI assessment.

A review of research on the intersection between breast cancer and cardiovascular research in the Women's Health Initiative (WHI)

Both obesity and metabolic syndrome are linked to increased incidence of type 2 diabetes, cardiovascular disease (CVD), and cancers of the breast (post-menopausal), and other obesity-related cancers. Over the past 50 years, the worldwide prevalence of obesity and metabolic syndrome has increased, with a concomitant higher incidence of associated co-morbidities and mortality. The precise mechanism linking metabolic syndrome to increased cancer incidence is incompletely understood, however, individual components of metabolic syndrome have been linked to increased breast cancer incidence and worse survival. There is a bidirectional relationship between the risk of CVD and cancer due to a high burden of shared risk factors and higher rates of CVD among cancer survivors, which may be impacted by the pro-inflammatory microenvironment associated with metabolic syndrome and cancer-directed therapies. The Women's Health Initiative (WHI) is an excellent resource to study a dual relationship between cancer and CVD (cardio-oncology) with extensive information on risk factors and long-term outcomes. The purpose of this review is to provide an overview of research on cardio-oncology conducted utilizing WHI data with focus on studies evaluating both breast cancer and CVD including shared risk factors and outcomes after cancer. The review also includes results on other obesity related cancers which were included in the analyses of breast cancer, articles looking at cancer after heart disease (reverse cardio-oncology) and the role of Clonal Hematopoiesis of Indeterminate Potential (CHIP) as a shared risk factor between CVD and cancer. A summary of pertinent WHI literature helps to delineate the direction of future research evaluating the relationship between CVD and other cancer sites, and provides information on the opportunity for other novel analyses within the WHI.

Body weight variability and cancer incidence in men aged 40 years and older-Korean National Insurance Service Cohort

Repeated weight fluctuation has been proposed as a potential risk factor for increasing morbidity and mortality including cancer. We aimed to investigate the association between body weight variability (BWV) and all cancer and site-specific cancer incidence and the impact of smoking on these associations. A total of 1,759,848 cancer-free male subjects who had their weight measured at least 5 times from the National Health Insurance Service-Health Screening Cohort from 2002 to 2011 were included and followed up until 2015. BWV was defined as the average absolute difference between successive values (ASV). The risk of cancer and site-specific cancer from BWV was identified using Cox proportional hazards regression analysis using hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders including weight, and stratified analysis was also conducted according to smoking status. During the 7,015,413 person-years of follow-up, 11,494 patients (0.65%) developed new-onset cancers. BWV was associated with a higher risk of all cancers after adjustment for confounders. The highest BWV quintile group compared to the lowest had greater risks of all cancers and site-specific cancers including lung, liver, and prostate cancer (HR 1.22, 95% CI 1.15–1.30; HR 1.22, 95% CI 1.07–1.39; HR 1.46, 95% CI 1.19–1.81; HR 1.36, 95% CI 1.15–1.62, in all cancers, lung, liver and prostate cancer, respectively). Due to small number of cancer occurrence, the risk of kidney cancer was increased, but statistically insignificant (HR 1.38, 95% CI 0.91–2.10). Similar results were observed in noncurrent smokers. However, in current smokers, the risks of all cancers and only prostate cancer were significantly increased in the highest BWV quintile group (HR 1.19, 95% CI 1.09–1.31; HR 1.51, 95% CI 1.08–2.11). The risk of kidney cancer also increased in this group, although the finding was not statistically significant (HR 1.77, 95% CI 0.87–3.63) This study suggested BWV is an independent risk factor for cancer in men, especially in lung, liver, and prostate cancer, but evidence was weaker in kidney cancer. This association remained significant only in prostate cancer in current smokers.

Body weight variability and the risk of cardiovascular outcomes in patients with nonalcoholic fatty liver disease

We investigated the association between body weight variability and the risks of cardiovascular disease and mortality in patients with nonalcoholic fatty liver disease (NAFLD) using large-scale, nationwide cohort data. We included 726,736 individuals with NAFLD who underwent a health examination between 2009 and 2010. NAFLD was defined as a fatty liver index ≥ 60, after excluding significant alcohol intake, viral hepatitis, and liver cirrhosis. Body weight variability was assessed using four indices, including variability independent of the mean (VIM). During a median 8.1-year follow-up, we documented 11,358, 14,714, and 22,164 cases of myocardial infarction (MI), stroke, and all-cause mortality, respectively. Body weight variability was associated with an increased risk of MI, stroke, and mortality after adjusting for confounding variables. The hazard ratios (HRs) (95% confidence intervals) for the highest quartile, compared with the lowest quartile, of VIM for body weight were 1.15 (1.10-1.20), 1.22 (1.18-1.26), and 1.56 (1.53-1.62) for MI, stroke, and all-cause mortality, respectively. Body weight variability was associated with increased risks of MI, stroke, and all-cause mortality in NAFLD patients. Appropriate interventions to maintain a stable weight could positively affect health outcomes in NAFLD patients.

Weight Regain and Breast Cancer-Related Biomarkers Following an Exercise Intervention in Postmenopausal Women

BACKGROUND

Epidemiologic studies have reported associations between weight fluctuations and postmenopausal breast cancer risk; however, the biological markers involved in this association are unknown. This study aimed to explore the associations between breast cancer-related biomarkers and weight regain following exercise-induced weight loss.

METHODS

From the 400 participants included in the Breast Cancer and Exercise Trial in Alberta, a total of 214 lost weight during the intervention and had follow-up blood samples, body composition, and covariate measurements. Outcomes were measured at baseline, 12 months (end of the study), and 24 months (follow-up).

RESULTS

During follow-up, weight regain was 1.80 kg [95% confidence interval (CI): -0.40-3.90], and was significantly associated with increases in estradiol [treatment effect ratio (TER) = 1.03; 95% CI, 1.01-1.04], estrone (TER = 1.02; 95% CI, 1.01-1.03), free estradiol (TER = 1.04; 95% CI, 1.02-1.05), the homeostatic model assessment for insulin resistance (TER = 1.03; 95% CI, 1.02-1.05), and insulin (TER = 1.03; 95% CI, 1.01-1.04), and decreases in sex hormone-binding globulin (SHBG; TER = 0.98; 95% CI, 0.97-0.99) levels. Nonstatistically significant associations were found for glucose and C-reactive protein. Furthermore, a statistically significant linear trend of increasing levels for all biomarkers, and decreasing SHBG, across weight regain categories was found.

CONCLUSIONS

These results suggest that weight regain following exercise-induced weight loss is associated with breast cancer-related biomarker changes in postmenopausal women.

IMPACT

These findings provide evidence to support the importance of developing effective strategies to prevent weight regain and, consequently, decrease postmenopausal breast cancer risk via changes in adiposity-related biomarkers.

The effect of bariatric surgery on breast cancer incidence and characteristics: A meta-analysis and systematic review

BACKGROUND

Obesity is a major risk factor for breast cancer. This study examines whether bariatric surgery affects breast cancer incidence in women with obesity compared to BMI-matched controls.

METHODS

EMBASE, MEDLINE, Web of Science, and CINAHL were searched. Primary studies on female breast cancer incidence after bariatric surgery were eligible.

RESULTS

11 studies were included (n = 1,106,939). The rate of cancer diagnosis was lower in the surgical group (0.54%) compared to control (0.84%; risk ratio (RR) 0.50, 95%CI 0.37-0.67, I² = 88%). The results were robust to sensitivity analyses for patient age and study size. Bariatric surgery was associated with increased risk of stage I cancer (RR 1.23, 95%CI 1.06-1.44) and reduced risk of stage III or IV cancer (RR 0.50, 95%CI 0.28-0.88). Hormone receptor characteristics were not affected.

CONCLUSIONS

Bariatric surgery is associated with reduced incidence and earlier stage at diagnosis of breast cancer in women with obesity compared to BMI-matched controls.

The Tumor Promotional Role of Adipocytes in the Breast Cancer Microenvironment and Macroenvironment

The role of the adipocyte in the tumor microenvironment has received significant attention as a critical mediator of the obesity-cancer relationship. Current estimates indicate that 650 million adults have obesity, and thirteen cancers, including breast cancer, are estimated to be associated with obesity. Even in people with a normal body mass index, adipocytes are key players in breast cancer progression because of the proximity of tumors to mammary adipose tissue. Outside the breast microenvironment, adipocytes influence metabolic and immune function and produce numerous signaling molecules, all of which affect breast cancer development and progression. The current epidemiologic data linking obesity, and importantly adipose tissue, to breast cancer risk and prognosis, focusing on metabolic health, weight gain, and adipose distribution as underlying drivers of obesity-associated breast cancer is presented here. Bioactive factors produced by adipocytes, both normal and cancer associated, such as cytokines, growth factors, and metabolites, and the potential mechanisms through which adipocytes influence different breast cancer subtypes are highlighted.

Ten-year weight gain is not associated with multiple cardiometabolic measures in Alaska EARTH study participants

BACKGROUND AND AIMS

Alaska Native (AN) traditional lifestyle may be protective against chronic disease risk. Weight gain in adulthood has been linked to increases in chronic disease risk among other populations; yet, its impact among Alaska Native people has never been evaluated. We aimed to evaluate changes in obesity-related metrics over time, and determine associations of changes with cardiometabolic markers of chronic disease risk among AN people.

METHODS AND RESULTS

Study participants enrolled in the southcentral Alaska Education and Research Towards Health Study in 2004-2006 were invited to participate in a follow-up study conducted 2015-2017. Of the original 1320 participants, 388 completed follow-up health assessments consisting of multiple health surveys, anthropometric measurements, and cardiometabolic measures including blood sugars, blood lipids, and blood pressure. Differences in measurements between visits were determined and associations of weight change with cardiometabolic measures evaluated. Body mass index increased by 3.7 kg/m2 among men and 4.8 kg/m2 among women. Hip circumference (1.1 cm, p < 0.01) and waist circumference (0.7 cm, p < 0.01) increased among women; only waist circumference increased among men (1.6 cm, p < 0.01). Among men, there were no associations of weight change with cardiometabolic measures. Among women, there was an inverse association between weight gain and high-density lipoprotein cholesterol only (0.17 mg/dL (CI: -3.1, -0.03), p = 0.02).

CONCLUSIONS

While weight increase over a 10-year period was not associated with substantive changes in cardiometabolic measures among AN men, there was a decrease in high density lipid cholesterol associated with weight gain among AN women.

Polycyclic Aromatic Hydrocarbons and Mammary Cancer Risk: Does Obesity Matter too?

Breast cancer risk remains incompletely explained, and higher incidence rates of breast cancer over recent times and in urban and industrialized areas suggest environmental causes. Polycyclic aromatic hydrocarbons (PAH) are ubiquitous in the environment and epidemiological and rodent studies have shown associations between exposure to PAH and breast cancer incidence as well as mammary tumorigenesis. In addition, in vitro and rodent studies have implicated alterations in estrogen receptor alpha (Erα) signaling pathways following PAH exposure in limited experimental studies. However, our understanding of these mechanisms is incomplete. Sahay et al. addressed this gap by examining the effect of PAH exposure on epigenetic and transcriptional regulation of genes in the Erα pathway in a mouse cohort exposed to aerosolized PAH at proportions measured in urban air. In addition to alterations in the Erα signaling pathway in the pregnant mice and in their offspring and grandoffspring, the investigators observed higher body weights in mice exposed to PAH compared to the control. Given that associations between mammary tissue adiposity, systemic adiposity, and breast cancer risk have been observed previously, the finding of higher body weight in the PAH exposure group raises the possibility that body weight might influence the association between PAH exposure and breast cancer risk. Along with new analyses, we discuss the possibility that body weight may modify the association between PAH exposure, mammary cellular proliferation, and mammary gland ductal hyperplasia in offspring and grandoffspring mice and future research that may be needed to delineate these associations.

Body shape trajectories and risk of breast cancer: results from the SUN ('Seguimiento Universidad De Navarra') Project

OBJECTIVE

The aim of this study was to assess body shape trajectories in childhood and midlife in relation to subsequent risk of breast cancer (BC) in a Mediterranean cohort.

DESIGN

The 'Seguimiento Universidad de Navarra' (SUN) Project is a dynamic prospective cohort study of university graduates initiated in 1999. With a group-based modelling approach, we assessed body shape trajectories from age 5 to 40 years. Multivariable Cox regression models were used to estimate the hazard ratio (HR) for BC after the age of 40 years according to the body shape trajectory.

SETTING

City of Pamplona, in the North of Spain.

PARTICIPANTS

6498 women with a mean age of 40 years (sd 9).

RESULTS

We identified four distinct body shape trajectories ('childhood lean-midlife increase' (19·9 %), 'childhood medium-midlife stable' (53 %), 'childhood heavy-midlife stable' (21 %) and 'childhood heavy-midlife increase' (6·1 %)). Among 54 978 women-years of follow-up, we confirmed eighty-two incident cases of BC. Women in the 'childhood lean-midlife increase' group showed a higher risk of BC (HR = 1·84, 95 % CI 1·11, 3·04) compared with women in the 'childhood medium-midlife stable' category. This association was stronger for postmenopausal BC (HR = 2·42, 95 % CI 1·07, 5·48).

CONCLUSIONS

Our results suggest a role for lifetime adiposity in breast carcinogenesis.

Data Imputation and Body Weight Variability Calculation Using Linear and Nonlinear Methods in Data Collected From Digital Smart Scales: Simulation and Validation Study

Background

Body weight variability (BWV) is common in the general population and may act as a risk factor for obesity or diseases. The correct identification of these patterns may have prognostic or predictive value in clinical and research settings. With advancements in technology allowing for the frequent collection of body weight data from electronic smart scales, new opportunities to analyze and identify patterns in body weight data are available.

Objective

This study aims to compare multiple methods of data imputation and BWV calculation using linear and nonlinear approaches

Methods

In total, 50 participants from an ongoing weight loss maintenance study (the NoHoW study) were selected to develop the procedure. We addressed the following aspects of data analysis: cleaning, imputation, detrending, and calculation of total and local BWV. To test imputation, missing data were simulated at random and using real patterns of missingness. A total of 10 imputation strategies were tested. Next, BWV was calculated using linear and nonlinear approaches, and the effects of missing data and data imputation on these estimates were investigated.

Results

Body weight imputation using structural modeling with Kalman smoothing or an exponentially weighted moving average provided the best agreement with observed values (root mean square error range 0.62%-0.64%). Imputation performance decreased with missingness and was similar between random and nonrandom simulations. Errors in BWV estimations from missing simulated data sets were low (2%-7% with 80% missing data or a mean of 67, SD 40.1 available body weights) compared with that of imputation strategies where errors were significantly greater, varying by imputation method.

Conclusions

The decision to impute body weight data depends on the purpose of the analysis. Directions for the best performing imputation methods are provided. For the purpose of estimating BWV, data imputation should not be conducted. Linear and nonlinear methods of estimating BWV provide reasonably accurate estimates under high proportions (80%) of missing data.

Weight change among repeat participants of an Aboriginal community-based weight loss program

Background

Community-based weight loss programs may have potential to address overweight and obesity at the population level. However, participation patterns and individual outcomes from these programs are understudied. This study examined repeat participation patterns and participant weight change between contests over seven years of an Aboriginal Australian team-based program in order to identify (1) predictors of repeat participation and (2) associations with weight change between contests.

Methods

Data for the 12 contests from 2012 to 2018 were merged, with probabilistic record matching. A total of 7510 enrolments were registered for the 12 contests, representing 4438 unique people. Contest lengths varied from 10 to 16 weeks in duration. Non-repeat participants were those who only competed once in the program by the end of 2018, and repeaters were those who competed in at least two contests. Associations between repeat participation and participant baseline (i.e., first participation occasion) characteristics, change in diet and physical activity and percent change in weight during the first participation occasion were examined using crossed random effects (for person and team) regression adjusted for exposure to the program. Weight percentage change between contests was calculated for consecutive participation occasions occurring at least three months apart, converted to percent change per month. Weight change was regressed on number of repeat participation occasions adjusted for age, gender, baseline weight at first participation occasion, and weight percent change in the immediately preceding contest.

Results

One-third of the 4433 participants participated more than once, with women more likely than men to repeat. A 1% reduction in weight during a competition was associated with an increase in weight of 0.05% per month between competition end and subsequent participation. Regain was smaller the heavier participants were at their first participation.

Conclusions

While individuals benefit from weight loss through program participation, strengthening strategies for weight loss maintenance within or following the program could improve long-term weight outcomes and reduce weight cycling.

Cancer Risk After Bariatric Surgery in a Cohort Study from the Five Nordic Countries

PURPOSE

Obesity increases the risk of several cancers, but the influence of bariatric surgery on the risk of individual obesity-related cancers is unclear. This study aimed to assess the impact of bariatric surgery on cancer risk in a multi-national setting.

MATERIALS AND METHODS

This cohort study included all adults with an obesity diagnosis identified from national patient registries in all Nordic countries (Denmark, Finland, Iceland, Norway and Sweden) from 1980 to 2012. Cancer risk in bariatric surgery patients was compared with non-operated patients with obesity. Multivariable Cox regression provided adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). Age, sex, calendar year, country, length of follow-up, diabetes, chronic obstructive pulmonary disease and alcohol-related diseases were evaluated as confounders.

RESULTS

Among 482,572 participants with obesity, 49,096 underwent bariatric surgery. Bariatric surgery was followed by a decreased overall cancer risk in women (HR 0.86, 95% CI 0.80-0.92), but not in men (HR 0.98, 95% CI 0.95-1.01). The risk reduction was observed only within the first five post-operative years. Among specific tumours, HRs decreased for breast cancer (HR 0.81, 95% CI 0.69-0.95), endometrial cancer (HR 0.69, 95% CI 0.56-0.84) and non-Hodgkin lymphoma (HR 0.64, 95% CI 0.42-0.97) in female bariatric surgery patients, while the risk of kidney cancer increased in both sexes (HR 1.44, 95% CI 1.13-1.84).

CONCLUSION

Bariatric surgery may decrease overall cancer risk in women within the first five years after surgery. This decrease may be explained by a decreased risk of breast and endometrial cancer and non-Hodgkin lymphoma in women.

Effects of Cardiovascular Risk Factor Variability on Health Outcomes

Innumerable studies have suggested "the lower, the better" for cardiovascular risk factors, such as body weight, lipid profile, blood pressure, and blood glucose, in terms of health outcomes. However, excessively low levels of these parameters cause health problems, as seen in cachexia, hypoglycemia, and hypotension. Body weight fluctuation is related to mortality, diabetes, obesity, cardiovascular disease, and cancer, although contradictory findings have been reported. High lipid variability is associated with increased mortality and elevated risks of cardiovascular disease, diabetes, end-stage renal disease, and dementia. High blood pressure variability is associated with increased mortality, myocardial infarction, hospitalization, and dementia, which may be caused by hypotension. Furthermore, high glucose variability, which can be measured by continuous glucose monitoring systems or self-monitoring of blood glucose levels, is associated with increased mortality, microvascular and macrovascular complications of diabetes, and hypoglycemic events, leading to hospitalization. Variability in metabolic parameters could be affected by medications, such as statins, antihypertensives, and hypoglycemic agents, and changes in lifestyle patterns. However, other mechanisms modify the relationships between biological variability and various health outcomes. In this study, we review recent evidence regarding the role of variability in metabolic parameters and discuss the clinical implications of these findings.

Role of Secreted Frizzled-Related Protein 1 in Early Mammary Gland Tumorigenesis and Its Regulation in Breast Microenvironment

In mice, the lack of secreted frizzled-related protein 1 (SFRP1) is responsible for mammogenesis and hyperplasia, while, in bovines, its overexpression is associated with post-lactational mammary gland involution. Interestingly, there are no reports dealing with the role of SFRP1 in female involution. However, SFRP1 dysregulation is largely associated with human tumorigenesis in the literature. Indeed, the lack of SFRP1 is associated with both tumor development and patient prognosis. Considering the increased risk of breast tumor development associated with incomplete mammary gland involution, it is crucial to demystify the "grey zone" between physiological age-related involution and tumorigenesis. In this review, we explore the functions of SFRP1 involved in the breast involution processes to understand the perturbations driven by the disappearance of SFRP1 in mammary tissue. Moreover, we question the presence of recurrent microcalcifications identified by mammography. In bone metastases from prostate primary tumor, overexpression of SFRP1 results in an osteolytic response of the tumor cells. Hence, we explore the hypothesis of an osteoblastic differentiation of mammary cells induced by the lack of SFRP1 during lobular involution, resulting in a new accumulation of hydroxyapatite crystals in the breast tissue.

Associations of weight cycling with cardiovascular health using American Heart Association's Life's Simple 7 in a diverse sample of women

Prior research shows that weight cycling is associated with poorer cardiovascular health (CVH). Women experience unique life events (e.g. pregnancy, menopause) which may make them more prone to weight cycling. Examining the influence of weight cycling history (HWC) on CVH, quantified using the American Heart Association's Life's Simple 7 (LS7), may provide novel targets to improve CVH. A cross-sectional sample of 485 women at Columbia University Irving Medical Center (2016-2018) were scored on each LS7 metric (BMI, blood pressure, fasting cholesterol and glucose, physical activity, diet, and smoking): 0 (low), 1 (moderate) or 2 (high). Metric points were summed into a composite LS7 score as a measure of CVH: 0-8 (low), 9-10 (moderate), 11-14 (high). Multivariable-adjusted logistic and linear regression models were used for the associations between HWC and CVH. Most women (73%) reported HWC (range: 0-20); 26% had low CVH and 74% moderate/high CVH. Logistic models showed HWC was associated with higher odds of having poor CVH [OR (95%CI): 2.39 (1.36-4.20)]. Linear models showed each additional weight cycling episode was associated with lower LS7 scores [ß(SE): -0.37 (0.07); p < 0.01]. Associations between HWC and odds of having poor CVH were stronger among pre-menopausal women and those with no pregnancy history (p-interaction = 0.009, 0.004, respectively). In conclusion, HWC was associated with higher odds of poorer CVH with stronger associations seen in pre-menopausal and women with no pregnancy history. These findings suggest that in addition to having a healthy weight, maintaining a consistent weight may be important for achieving optimal CVH, but warrant prospective confirmation.

Intentional weight loss, weight cycling, and endometrial cancer risk: a systematic review and meta-analysis

PURPOSE

Weight cycling, defined as intentional weight loss followed by unintentional weight regain, may attenuate the benefit of intentional weight loss on endometrial cancer risk. We summarized the literature on intentional weight loss, weight cycling after intentional weight loss, bariatric surgery, and endometrial cancer risk.

METHODS

A systematic search was conducted using MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases published between January 2000 and November 2018. We followed Preferred Reporting Items of Systematic Reviews and Meta-analysis (PRISMA) guidelines. We qualitatively summarized studies related to intentional weight loss and weight cycling due to the inconsistent definition, and quantitatively summarized studies when bariatric surgery was the mechanism of intentional weight loss.

RESULTS

A total of 127 full-text articles were reviewed, and 13 were included (bariatric surgery n=7, self-reported intentional weight loss n=2, self-reported weight cycling n=4). Qualitative synthesis suggested that, compared with stable weight, self-reported intentional weight loss was associated with lower endometrial cancer risk (RR range 0.61-0.96), whereas self-reported weight cycling was associated with higher endometrial cancer risk (OR range 1.07-2.33). The meta-analysis yielded a 59% lower risk of endometrial cancer following bariatric surgery (OR 0.41, 95% CI 0.22 to 0.74).

CONCLUSIONS

Our findings support the notion that intentional weight loss and maintenance of a stable, healthy weight can lower endometrial cancer risk. Strategies to improve awareness and maintenance of weight loss among women with obesity are needed to reduce endometrial cancer risk.

World Cancer Research Fund International: Continuous Update Project-systematic literature review and meta-analysis of observational cohort studies on physical activity, sedentary behavior, adiposity, and weight change and breast cancer risk

PURPOSE

The purpose of the present study was to systematically review the complex associations between energy balance-related factors and breast cancer risk, for which previous evidence has suggested different associations in the life course of women and by hormone receptor (HR) status of the tumor.

METHODS

Relevant publications on adulthood physical activity, sedentary behavior, body mass index (BMI), waist and hip circumferences, waist-to-hip ratio, and weight change and pre- and postmenopausal breast cancer risk were identified in PubMed up to 30 April 2017. Random-effects meta-analyses were conducted to summarize the relative risks across studies.

RESULTS

One hundred and twenty-six observational cohort studies comprising over 22,900 premenopausal and 103,000 postmenopausal breast cancer cases were meta-analyzed. Higher physical activity was inversely associated with both pre- and postmenopausal breast cancers, whereas increased sitting time was positively associated with postmenopausal breast cancer. Although higher early adult BMI (ages 18-30 years) was inversely associated with pre- and postmenopausal breast cancers, adult weight gain and greater body adiposity increased breast cancer risk in postmenopausal women, and the increased risk was evident for HR+ but not HR- breast cancers, and among never but not current users of postmenopausal hormones. The evidence was less consistent in premenopausal women. There were no associations with adult weight gain, inverse associations with adult BMI (study baseline) and hip circumference, and non-significant associations with waist circumference and waist-to-hip ratio that were reverted to positive associations on average in studies accounting for BMI. No significant associations were observed for HR-defined premenopausal breast cancers.

CONCLUSION

Better understanding on the impact of these factors on pre- and postmenopausal breast cancers and their subtypes along the life course is needed.

Weight Management and Physical Activity for Breast Cancer Prevention and Control

Observational evidence has consistently linked excess adiposity and inactivity to increased breast cancer risk and to poor outcomes in individuals diagnosed with early-stage, potentially curable breast cancer. There is less information from clinical trials testing the effect of weight management or physical activity interventions on breast cancer risk or outcomes, but a number of ongoing trials will test the impact of weight loss and other lifestyle changes after cancer diagnosis on the risk of breast cancer recurrence. Lifestyle changes have additional benefits beyond their potential to decrease primary or secondary breast cancer risk, including improvements in metabolic parameters, reduction in the risk of comorbidities such as diabetes and heart disease, improvement of physical functioning, and mitigation of side effects of cancer therapy. Despite these myriad benefits, implementation of lifestyle interventions in at-risk and survivor populations has been limited to date. This article reviews the evidence linking lifestyle factors to breast cancer risk and outcomes, discusses completed and ongoing randomized trials testing the impact of lifestyle change in primary and secondary breast cancer prevention, and reviews efforts to implement and disseminate lifestyle interventions in at-risk and breast cancer survivor populations.

Burden of cancer attributable to obesity, type 2 diabetes and associated risk factors

Overweight and obesity constitute a global pandemic with devastating consequences that affect >2 billion people. Obesity plays a central role in morbidity and mortality of diseases of multiple organs and systems, and it is a major contributor to the growing incidence of cancer. There is now sufficient level of evidence for the association between overweight and 11 types of cancer, among which are two of the most common cancers worldwide, those of the colorectum and postmenopausal breast. Sedentary lifestyle, unhealthy diet, and excessive alcohol intake also account for the burden of cancer by promoting obesity. The risk of specific types of cancer is also directly influenced, regardless of the magnitude of adiposity, by physical inactivity, consumption of red meat, processed meat and ultra-processed foods, dairy products, alcohol, whole grain cereals, nuts, vegetables, and fruits. Type 2 diabetes is another global health threat closely associated with obesity that boosts the risk of cancer driven by high BMI. Education to promote positive choices and physical activity and resolute public health interventions on food delivery are requested to reduce the burden of obesity-related cancer and lighten the unsustainable growing expenses to health systems.

Epidemiology of Breast Cancer in Women

Epidemiologic studies have contributed importantly to current knowledge of environmental and genetic risk factors for breast cancer. Worldwide, breast cancer is an important cause of human suffering and premature mortality among women. In the United States, breast cancer accounts for more cancer deaths in women than any site other than lung cancer. A variety of risk factors for breast cancer have been well-established by epidemiologic studies including race, ethnicity, family history of cancer, and genetic traits, as well as modifiable exposures such as increased alcohol consumption, physical inactivity, exogenous hormones, and certain female reproductive factors. Younger age at menarche, parity, and older age at first full-term pregnancy may influence breast cancer risk through long-term effects on sex hormone levels or by other biological mechanisms. Recent studies have suggested that triple negative breast cancers may have a distinct etiology. Genetic variants and mutations in genes that code for proteins having a role in DNA repair pathways and the homologous recombination of DNA double stranded breaks (APEX1, BRCA1, BRCA2, XRCC2, XRCC3, ATM, CHEK2, PALB2, RAD51, XPD), have been implicated in some cases of breast cancer.

Induction of uterine hyperplasia after cafeteria diet exposure

Our aim was to evaluate whether chronic administration of CAF affects the uterus and induces the morphological and molecular changes associated with endometrial hyperplasia. Female Wistar rats exposed to CAF from weaning for 20 weeks displayed increased energy intake, body weight and fat depots, but did not develop metabolic syndrome. The adult uteri showed an increase in glandular volume fraction and stromal area. The epithelial proliferation rate and protein expression of oestrogen receptor alpha (ERα) were also increased. The CAF diet enhanced leptin serum levels and the long form of leptin receptor (Ob-Rb) mRNA expression in the uterus. No changes were detected in either insulin serum levels or those of insulin growth factor I (IGF-I) mRNA expression. However the levels of IGF-I receptor (IGF-IR) mRNA were lower in CAF-fed animals. Overall, the results indicate that our rat model of the CAF diet produces morphological and molecular changes associated with uterine hyperplasia and could predispose to endometrial carcinogenesis.

Prevention Strategies in Endometrial Carcinoma

PURPOSE OF THE REVIEW

To assess the most recent high-quality evidence for endometrial cancer prevention strategies.

RECENT FINDINGS

Obesity is an established risk factor for endometrial cancer. Weight cycling and weight gain in middle age are risk factors for endometrial cancer. Bariatric surgery reduces the risk of endometrial cancer by up to 81% in obese women who attain and maintain a normal weight. Combined oral contraceptives provide durable protection against endometrial cancer for 30 years or more. Ever use of the levonorgestrel intrauterine system (LNG-IUS) and inert intrauterine devices reduce endometrial cancer risk. The first oestrogen-based non-progestin HRT for non-hysterectomised women that contains estradiol and bazedoxifene has an effective protective effect on endometrium. Bisphosphonates reduce endometrial cancer risk. Weight loss and LNG-IUS would seem to be an effective strategy for preventing the development of obesity-driven endometrial cancer in the highest risk women. Future research may identify other safe and effective chemoprevention interventions, such as aspirin, bisphosphonates or metformin.

Associations of clothing size, adiposity and weight change with risk of postmenopausal breast cancer in the UK Women's Cohort Study (UKWCS)

OBJECTIVES

Breast cancer is associated with overweight and obesity after menopause. However, clothing size as a proxy of adiposity in predicting postmenopausal breast cancer is not widely studied. We aimed to explore the relationships between postmenopausal breast cancer risk with adipose indicators (including clothing sizes) and weight change over adulthood.

DESIGN

Prospective cohort study.

SETTING

England, Wales and Scotland.

PARTICIPANTS

17 781 postmenopausal women from the UK Women's Cohort Study.

PRIMARY OUTCOME MEASURE

Incident cases of malignant breast cancers (International Classification of Diseases (ICD) 9 code 174 and ICD 10 code C50).

RESULTS

From 282 277 person-years follow-up, there were 946 incident breast cancer cases with an incidence rate of 3.35 per 1000 women. Body mass index (HR: 1.04; 95% CI: 1.02 to 1.07), blouse size (HR: 1.10; 1.03 to 1.18), waist circumference (HR: 1.07; 1.01 to 1.14) and skirt size (HR: 1.14;1.06 to 1.22) had positive associations with postmenopausal breast cancer after adjustment for potential confounders. Increased weight over adulthood (HR: 1.02; 1.01 to 1.03) was also associated with increased risk for postmenopausal breast cancer.

CONCLUSIONS

Blouse and skirt sizes can be used as adipose indicators in predicting postmenopausal breast cancer. Maintaining healthy body weight over adulthood is an effective measure in the prevention of postmenopausal breast cancer.

The relationship between body mass index changes during chemotherapy and prognosis of patients with advanced colorectal cancer: A retrospective cohort study

We investigated the relationships between body mass index change (ΔBMI) and prognoses and clinical effects of patients with advanced colorectal cancer (CRC).From January 2008 to December 2012, 224patients with stage IV CRC were diagnosed in our hospital, and their clinical and pathological data were collected for this retrospective study. These patients were divided into lowΔ BMI group (ΔBMI ≤-0.45 kg/m) and high ΔBMI (ΔBMI >-0.45 kg/m) group.After 2 cycles of chemotherapy, there were no significant differences between prediagnosis BMI, ΔBMI, and clinical effects (P = .196; P = .59).There was also no significant difference in median progression-free survival of the high ΔBMI and low ΔBMI groups (P = .530). The overall survival (OS) time of the high ΔBMI group was significantly longer than that of the low ΔBMI group (P = .002). Family history (P = .041), eastern cooperative oncology group performance status (ECOG PS) score (P = .001), ΔBMI (P = .023), and carcinoembryonic antigen, (P = 0.02) were independent predictive factors of OS rates in patients with CRC. The relative risk was 0.72-fold for patients with CRC patients with high ΔBMI levels, relative to those with lower ΔBMI levels.Our results demonstrate that ΔBMI decreases predict poor prognoses for patients with advanced CRC, and elevated ΔBMI was a predictive factor for high survival rate. Thus, ΔBMI appears to be an independent predictive factor of CRC survival rates.

Obesity and breast cancer - Role of estrogens and the molecular underpinnings of aromatase regulation in breast adipose tissue

One in eight women will develop breast cancer over their lifetime making it the most common female cancer. The cause of breast cancer is multifactorial and includes hormonal, genetic and environmental cues. Obesity is now an accepted risk factor for breast cancer in postmenopausal women, particularly for the hormone-dependent subtype of breast cancer. Obesity, which is characterized by an excess accumulation of body fat, is at the origin of chronic inflammation of white adipose tissue and is associated with dramatic changes in the biology of adipocytes leading to their dysfunction. Inflammatory factors found in the breast of obese women considerably impact estrogen signaling, mainly by driving changes in aromatase expression the enzyme responsible for estrogen production, and therefore promote tumor formation and progression. There is thus a strong link between adipose inflammation and estrogen biosynthesis and their signaling pathways converge in obese patients. This review describes how obesity-related factors can affect the risk of hormone-dependent breast cancer, highlighting the different molecular mechanisms and metabolic pathways involved in aromatase regulation, estrogen production and breast malignancy in the context of obesity.

Melatonin: A Molecule for Reducing Breast Cancer Risk

The objective of this article is to review the basis supporting the usefulness of melatonin as an adjuvant therapy for breast cancer (BC) prevention in several groups of individuals at high risk for this disease. Melatonin, as a result of its antiestrogenic and antioxidant properties, as well as its ability to improve the efficacy and reduce the side effects of conventional antiestrogens, could safely be associated with the antiestrogenic drugs presently in use. In individuals at risk of BC due to night shift work, the light-induced inhibition of melatonin secretion, with the consequent loss of its antiestrogenic effects, would be countered by administering this neurohormone. BC risk from exposure to metalloestrogens, such as cadmium, could be treated with melatonin supplements to individuals at risk of BC due to exposure to this xenoestrogen. The BC risk related to obesity may be reduced by melatonin which decrease body fat mass, inhibits the enhanced aromatase expression in obese women, increases adiponectin secretion, counteracts the oncogenic effects of elevated concentrations of leptin; and decreases blood glucose levels and insulin resistance. Despite compelling experimental evidence of melatonin's oncostatic actions being susceptible to lowering BC risk, there is still a paucity of clinical trials focused on this subject.