Cancers in Australia in 2010 attributable to overweight and obesity

Joint association of drinking alcohol and obesity in relation to cancer risk: A systematic review and data synthesis

BACKGROUND

Rates of alcohol consumption and obesity are increasing in many Western populations. For some cancer types, both heavy alcohol consumption and obesity are independently associated with increased risk. Whether combined exposure to both synergistically increases an individual's risk of cancer is unclear. We performed a systematic review to assess whether alcohol and obesity interact to confer higher risk for cancer than the additive sum of their effects.

METHODS

A systematic literature search was conducted from the inception date to 13 February 2024 of PubMed, Embase, Cochrane Library and Web of Science to identify studies of alcohol, obesity, and cancer risk. We aimed to undertake a meta-analysis if there were sufficient data.

RESULTS

The literature search identified 17,740 potentially eligible studies. After review, 24 studies were included. Eleven reported on the association between alcohol consumption and cancer risk in individuals according to their body mass index (BMI), nine reported on the association between BMI and cancer risk in individuals according to their alcohol consumption, and six studies examined potential synergistic interactions between alcohol consumption and obesity on cancer risk. However, there were insufficient data and significant heterogeneity in the cancers studied to undertake meta-analysis, therefore a systemic review and narrative synthesis was conducted. Overall, there was no consistent pattern of interaction between alcohol use and overweight/obesity on cancer risk across cancer types.

CONCLUSIONS

While alcohol and obesity are prevalent and important risk factors for a range of cancers, data are lacking on whether their combined exposure may synergistically increase an individual's risk for cancer. Further study across more cancer types is required to better understand the nature of interactions between alcohol use and obesity on cancer risk.

Cancers attributable to overweight and obesity in Italy

BACKGROUND & AIMS

Overweight and obesity are associated with multiple cancers. We quantified the burden of cancer attributable to overweight and obesity in Italy.

METHODS

We estimated sex- and cancer site-specific population attributable fractions (PAFs) combining relative risks (from recent meta-analyses) with national obesity prevalence data (from a large sample survey conducted in 2005, to account for a 15-year lag period). Using nationwide mortality statistics and cancer registries data, we estimated the number of cancer cases and deaths attributable to overweight and obesity in Italy in 2020, based on the counterfactual scenario of a body mass index < 25 kg/m2.

RESULTS

3.6% of cancers in men and 4.0% in women in Italy were attributable to overweight and obesity, corresponding, respectively, to over 6900 and 7200 diagnoses in 2020. Attributable deaths were over 3600 in men and 2700 in women. PAFs (attributable cases) of overweight and obesity in men and women were, respectively, 38.1% (215 cases) and 21.8% (49 cases) for esophageal adenocarcinoma, 19.1% (1715 cases) and 14.5% (585 cases) for liver, 18.7% (1692 cases) and 16.7% (747 cases) for kidney, 13.7% (938 cases) and 10.1% (749 cases) for pancreatic, and 10.2% (2389 cases) and 3.4% (690 cases) for colorectal cancers. In women, PAFs were 22.3% (1859 cases) for endometrial and 5.7% (2556 cases) for post-menopausal breast cancer.

CONCLUSIONS

The cancer burden associated with overweight and obesity in Italy is considerable, but smaller compared to other high income countries, likely because of the lower prevalence of overweight and obesity in the Italian population.

Overweight and obesity in adulthood, sociodemographic factors, lifestyle, and the early burden of noncommunicable diseases among Americans: NHANES 2007-2018

OBJECTIVES

To evaluate the association between nutritional status in early adulthood and the burden of noncommunicable diseases (NCDs); To evaluate the influence of sociodemographic factors and lifestyle on the outcomes of BMI kg/m2  ≤24.9, ≥25.0, and ≥30.0; to estimate the population attributable fraction (PAF) to BMI elevated at 25 years old in the burden of NCDs in American adults.

METHODS

We used data from 15 721 American adults participating in the National Health and Nutrition Examination Survey from 2007 to 2018. The Hazard Ratio (HR), Incidence Rate Ratio (IRR), and 95% confidence intervals (CI) were estimated in the proportional risk regression models of Cox (entire population) and Poisson (restricted to non-patients), respectively. The proportionality of the risk between the burden of NCDs and BMI at 25 years old was drawn by the Kaplan-Meier curve, and the PAF was calculated. All analyses were adjusted taking into account the sample weights.

RESULTS

Health disparities (sex, age, race/ethnicity, education, poverty index, and education level), and lifestyle (physical activity, smoking, and alcohol consumption) influenced the current nutritional status. Cumulative survival in overweight and obese groups decreased considerably over time (p < .0001). Being overweight and obese in adulthood may increase the risk of early NCDs (HR: 1.68, 95% CI: 1.54-1.84 and HR: 2.87, 95% CI: 2.56-3.21, respectively). About 22.72% (95% CI: 19.99-25.36, p < .001) of the burden NCDs could have been avoided if overweight at age 25 had been prevented.

CONCLUSIONS

Monitoring weight change from young adulthood can provide a sensitive and useful clinical measure for early detection of adverse trends in NCDs risk.

The future burden of oesophageal and stomach cancers attributable to modifiable behaviours in Australia: a pooled cohort study

BACKGROUND

We quantified the individual and joint contribution of contemporaneous causal behavioural exposures on the future burden of oesophageal and stomach cancers and their subtypes and assessed whether these burdens differ between population groups in Australia, as such estimates are currently lacking.

METHODS

We combined hazard ratios from seven pooled Australian cohorts (N = 367,058) linked to national cancer and death registries with exposure prevalence from the 2017-2018 National Health Survey to estimate Population Attributable Fractions (PAFs) with 95% confidence intervals (CIs), accounting for competing risk of death.

RESULTS

Current and past smoking explain 35.2% (95% CI = 11.7-52.4%), current alcohol consumption exceeding three drinks/day 15.7% (95% CI = 0.9-28.4%), and these exposures jointly 41.4% (95% CI = 19.8-57.3%) of oesophageal squamous cell carcinomas in Australia. Current and past smoking contribute 38.2% (95% CI = 9.4-57.9%), obesity 27.0% (95% CI = 0.6-46.4%), and these exposures jointly 54.4% (95% CI = 25.3-72.1%) of oesophageal adenocarcinomas. Overweight and obesity explain 36.1% (95% CI = 9.1-55.1%), current and past smoking 24.2% (95% CI = 4.2-40.0%), and these exposures jointly 51.2% (95% CI = 26.3-67.8%) of stomach cardia cancers. Several population groups had a significantly higher smoking-attributable oesophageal cancer burden, including men and those consuming excessive alcohol.

CONCLUSIONS

Smoking is the leading preventable behavioural cause of oesophageal cancers and overweight/obesity of stomach cancers.

Exploring grandparents' receptivity to and preferences for a grandchild nutrition-focused intervention: A qualitative study

OBJECTIVE

Interventions promoting healthy eating in children typically overlook the critical role of grandparent caregivers. Utilising a co-design approach, this study (i) assessed the receptiveness of grandparents to a nutrition-focused resource aimed at promoting healthy eating in their grandchildren and (ii) explored grandparents' preferences for resource delivery and dissemination.

METHODS

Seventy-nine grandparents (58% female; mean age=69.37 years) who were secondary carers to a grandchild aged 3-12 years participated in one of 10 focus groups. Focus group transcripts were imported into NVivo for coding and semantic thematic analysis.

RESULTS

The vast majority of focus groups (n=9) were receptive to receiving a nutrition-focused resource. Participants indicated that such a resource should contain strategies that help grandparents promote healthy eating in their grandchildren rather than outline what grandchildren should be fed. A range of delivery (pamphlets, seminars and fridge magnets) and dissemination (online, email) methods were suggested.

CONCLUSIONS

A nutrition resource that equips grandparents with the strategies they need to promote healthy eating in their grandchildren would likely be welcomed.

IMPLICATIONS FOR PUBLIC HEALTH

Results provide program developers with the preliminary information required to tailor childhood lifestyle interventions to the needs of grandparents, thus helping increase acceptability and uptake.

An ecological study of obesity-related cancer incidence trends in Australia from 1983 to 2017

BACKGROUND

Overweight and obesity is a growing public health issue as it contributes to the future burden of obesity-related diseases, including cancer, especially in high-income countries. In Australia, 4.3% of all cancers diagnosed in 2013 were attributable to overweight and obesity. Our aim was to examine Australian age-specific incidence trends over the last 35 years for obesity-related cancers based on expert review (colorectal, liver, gallbladder, pancreas, breast in postmenopausal women, uterine, ovary, kidney, thyroid, and multiple myeloma) individually and pooled.

METHODS

Australian incidence data for 10 obesity-related cancers among people aged 25-84 years, diagnosed from 1983 to 2017, were obtained from the Australian Cancer Database. We used age-period-cohort modelling and joinpoint analysis to assess trends, estimating incidence rate ratios (IRR) by birth-cohort for each individual cancer and pooled, and the annual percentage change. The analyses were also conducted for non-obesity-related cancers over the same period.

FINDINGS

The total number of cancers where some proportion is obesity-related, diagnosed from 1983-2017, was 1,005,933. This grouping was 34.7% of cancers diagnosed. The IRR of obesity-related cancers increased from 0.77 (95% CI 0.73, 0.81) for the 1903 birth-cohort to 2.95 (95% CI 2.58, 3.38) for the recent 1988 cohort relative to the 1943 cohort. The IRRs of non-obesity related cancers were stable with non-significant decreases in younger cohorts. These trends were broadly similar across sex and age groups.

INTERPRETATION

The incidence of obesity-related cancers in Australia has increased by birth-cohort across all age-groups, which should be monitored. Obesity, a public health epidemic, needs to be addressed through increased awareness, policy support and evidence-based interventions.

FUNDING

This research received no specific funding.

Projections of the future burden of cancer in Australia using Bayesian age-period-cohort models

BACKGROUND

Accurate forecasts of cancer incidence, with appropriate estimates of uncertainty, are crucial for planners and policy makers to ensure resource availability and prioritize interventions. We used Bayesian age-period-cohort (APC) models to project the future incidence of cancer in Australia.

METHODS

Bayesian APC models were fitted to counts of cancer diagnoses in Australia from 1982 to 2016 and projected to 2031 for seven key cancer types: breast, colorectal, liver, lung, non-Hodgkin lymphoma, melanoma and stomach. Aggregate cancer data from population-based cancer registries were sourced from the Australian Institute of Health and Welfare.

RESULTS

Over the projection period, total counts for these cancer types increased on average by 3 % annually to 100 385 diagnoses in 2031, which is a 50 % increase over 2016 numbers, although there is considerable uncertainty in this estimate. Counts for each cancer type and sex increased over the projection period, whereas decreases in the age-standardized incidence rates (ASRs) were projected for stomach, colorectal and male lung cancers. Large increases in ASRs were projected for liver and female lung cancer. Increases in the percentage of colorectal cancer diagnoses among younger age groups were projected. Retrospective one-step-ahead projections indicated both the incidence and its uncertainty were successfully forecast.

CONCLUSIONS

Increases in the projected incidence counts of key cancer types are in part attributable to the increasing and ageing population. The projected increases in ASRs for some cancer types should increase motivation to reduce sedentary behaviour, poor diet, overweight and undermanagement of infections. The Bayesian paradigm provides useful measures of the uncertainty associated with these projections.

Prevalence of MMTV-Like env Sequences and Its Association with BRCA1/2 Genes Mutations Among Egyptian Breast Cancer Patients

Background

Mouse mammary tumor virus (MMTV) is thought to have a role in human breast cancer (BC) pathogenesis. BRCA1 and 2 genes mutations are well-established risk factors for BC. The purpose of this study was to evaluate the presence of MMTV in familial and non-familial Egyptian breast cancer patients. We also aimed to establish a correlation between BRCAs genes mutations and MMTV infection in those patients.

Patients and Methods

The study was included 80 BC patients and 10 healthy women were included as a control group. We used PCR to amplify a 250-bp MMTV-like env sequence. We also used PCR followed by direct sequencing to identify the genetic variation of exons 2, 13, 19 of BRCA1 gene and exon 9 and region f of exon 11 of BRCA2 gene. High resolution melting (HRM) analysis was used to screen the selected exons of BRCA1/2 genes in order to detect different variants.

Results

MMTV DNA-like env sequences were detected in 70%, 76% of familial and non-familial BC patients, respectively, and it was not detected in any of the control subjects. The presence of viral sequences was associated with larger tumor size in the sporadic patients. Seventy BC patients showed variations in BRCA1/2 genes according to HRM analysis and sequencing analysis showed two different sequences of polymorphism among 22 familial and non-familial BC patients.

Conclusion

MMTV DNA was present among BC patients and it was associated with increased tumor growth. This indicates a potential role for MMTV in BC patients with and without deleterious mutation in BRCA1/2 genes.

Relative contribution of overweight and obesity to rising public hospital in-patient expenditure in South Australia

Objective Arguments to fund obesity prevention have often focused on the growing hospital costs of associated diseases. However, the relative contribution of overweight and obesity to public hospital expenditure growth is not well understood. This paper examines the effect of overweight and obesity on acute public hospital in-patient expenditure in South Australia over time compared with other expenditure drivers. Methods Annual inflation-adjusted acute public admitted expenditure attributable to a high body mass index was estimated for 2007-08 and 2011-12 and compared with other expenditure drivers. Results Expenditure attributable to overweight and obesity increased by A$45million, from 4.7% to 5.4% of total acute public in-patient expenditure. This increase accounted for 7.8% of the A$583million total expenditure growth, whereas the largest component of total growth (62.4%) was a real increase in the average cost per separation. Conclusions The relatively minor contribution of overweight and obesity to expenditure growth over the time period examined invites reflection on arguments to boost preventive spending that centre upon reducing hospital costs. These arguments may inadvertently detract attention from the considerable health and social burdens of overweight and obesity and from unrelated sources of expenditure growth that reduce opportunities for state governments to fund obesity prevention programs despite their comparative benefits to population health. What is known about the topic? Stand-alone estimates suggest that overweight and obesity are placing a considerable financial burden on the Australian public healthcare system. What does this paper add? Our findings challenge common perceptions about the relative importance of overweight and obesity in the context of rising public in-patient expenditure in Australia. What are the implications for practitioners? Consistent serial estimates of overweight- and obesity-attributable expenditure enable its tracking and comparison with other potentially controllable expenditure drivers that may also warrant attention. Explicit consideration of population health trade-offs in expenditure-related decisions, including in enterprise bargaining, would enhance transparency in priority setting.

Cancer costs and gender: a snapshot of issues, trends, and opportunities to reduce inequities using Australia as an example

As the cancer burden increases, so too does the cost, to health systems, economies, and individuals. There is increasing interest in productivity and out-of-pocket costs for individuals and their carers, but these remain poorly understood. The costs of cancer in women, often carers themselves, are less understood. This summary analysis explored data on the cancer burden in Australia (and health costs in comparable countries), including expenditure reports and literature on macroeconomic outcomes and out-of-pocket costs, to highlight the cost impacts of a cancer diagnosis in women, at a societal and an individual level. Data on productivity costs were skewed toward men, as men are over-represented in paid work compared with women. Data on societal and individual costs of cancer in women were scant, yet the predominance of women in unpaid work suggests the cost is significant. Evidence for the benefits of cancer prevention and early detection suggests that improved targeting of interventions to women would reduce costs at a societal and an individual level. More research is needed on the specific impacts of cancer on women and those they care for, to better target public health and support services to need.

Cancers Attributable to Overweight and Obesity From 2012 to 2014 in Nigeria: A Population-Based Cancer Registry Study

Background: Overweight and obesity are known risk factors for chronic diseases including cancers. In this study, we evaluated the age standardized incidence rates (ASR) and proportion of cancers attributable to overweight and obesity in Nigeria. Methods: We obtained incidence data from the databases of two population-based cancer registries (PBCRs) in Nigeria (Abuja and Enugu cancer registries), on cancer site for which there is established evidence of an association with overweight or obesity based on the International Agency for Research on Cancer (IARC) and the World Cancer Research Fund (WCRF) classification. We analyzed the data using population attributable fraction (PAF) for overweight or obesity associated cancers calculated using prevalence data and relative risk estimates in previous studies. Results: The two PBCRs reported 4,336 new cancer cases (ASR 113.9 per 100,000) from 2012 to 2014. Some 21% of these cancers were associated with overweight and obesity. The ASR for overweight and obesity associated cancers was 24.5 per 100,000; 40.7 per 100,000 in women and 8.2 per 100,000 in men. Overall, only 1.4% of incident cancers were attributable to overweight and obesity. The ASR of cancers attributable to overweight and obesity was 2.0 per 100,000. Postmenopausal breast cancer was the most common cancer attributable to overweight and obesity (n = 25; ASR 1.2 per 100,000). Conclusion: Our results suggest that a small proportion of incident cancer cases in Nigeria are potentially preventable by maintaining normal body weight. The burden of cancer attributed to overweight and obesity in Nigeria is relatively small, but it may increase in future.

Estimates of the current and future burden of cancer attributable to excess body weight and abdominal adiposity in Canada

The increasing prevalence of obesity among Canadians has important implications for newly diagnosed cases of cancer given that excess body weight and abdominal adiposity are known to increase the risk of several cancers. The purpose of this analysis was to estimate the current attributable and future avoidable burden of cancer related to excess body weight and abdominal adiposity among Canadian adults. We estimated the population attributable risk (PAR) for all cancers associated with excess body weight and abdominal adiposity using contemporary cancer incidence, relative risk and exposure prevalence data for body mass index (BMI), waist circumference and waist-to-hip-ratio. Using the partial impact fraction (PIF), we also estimated the future avoidable burden of cancer from 2015 to 2042 in Canada, and by province, through various hypothetical intervention scenarios. In 2003, approximately half (50.5%) of the Canadian population was estimated to be overweight (BMI 25.0-29.9) or obese (BMI ≥30.0), 56.5% to have excess abdominal adiposity and 56.8% with a high waist-to-hip ratio. In 2015, the estimated PARs of all incident cancers associated with excess body weight, excess abdominal adiposity and high waist-to-hip ratio were 7.2%, 8.9% and 10.0%, respectively. If the population BMI could revert to its 1994 distribution, 72,157 associated cancer cases could be prevented cumulatively by 2042. A reduction in excess body weight and abdominal adiposity has the potential to decrease the future cancer burden in Canada substantially, and hence efforts to reverse increasing trends in obesity should be prioritized.

The burden of pancreatic cancer in Australia attributable to smoking

OBJECTIVE

To estimate the burden of pancreatic cancer in Australia attributable to modifiable exposures, particularly smoking.

DESIGN

Prospective pooled cohort study.

SETTING, PARTICIPANTS

Seven prospective Australian study cohorts (total sample size, 365 084 adults); participant data linked to national registries to identify cases of pancreatic cancer and deaths.

MAIN OUTCOME MEASURES

Associations between exposures and incidence of pancreatic cancer, estimated in a proportional hazards model, adjusted for age, sex, study, and other exposures; future burden of pancreatic cancer avoidable by changes in exposure estimated as population attributable fractions (PAFs) for whole population and for specific population subgroups with a method accounting for competing risk of death.

RESULTS

There were 604 incident cases of pancreatic cancer during the first 10 years of follow-up. Current and recent smoking explained 21.7% (95% CI, 13.8-28.9%) and current smoking alone explained 15.3% (95% CI, 8.6-22.6%) of future pancreatic cancer burden. This proportion of the burden would be avoidable over 25 years were current smokers to quit and there were no new smokers. The burden attributable to current smoking is greater for men (23.9%; 95% CI, 13.3-33.3%) than for women (7.2%; 95% CI, -0.4% to 14.2%; P = 0.007) and for those under 65 (19.0%; 95% CI, 8.1-28.6%) than for older people (6.6%; 95% CI, 1.9-11.1%; P = 0.030). There were no independent relationships between body mass index or alcohol consumption and pancreatic cancer.

CONCLUSIONS

Strategies that reduce the uptake of smoking and encourage current smokers to quit could substantially reduce the future incidence of pancreatic cancer in Australia, particularly among men.

Leitzmann M, Brenner*2 H, Mons*2 U. Cancers Due to Excess Weight, Low Physical Activity, and Unhealthy Diet

BACKGROUND

Excess weight, low physical activity, low intakes of dietary fiber, fruits, and vegetables, and high meat and salt intake increase cancer risk.

METHODS

Numbers and proportions (population-attributable fractions, PAF) of incident cancer cases in Germany in 2018 attributable to these factors were estimated by sex and age groups for ages 35 to 84 years using population projections, national cancer incidence and exposure data, and published risk estimates.

RESULTS

Estimated numbers (percentages) of attributable cancers were 30 567 (7%) for excess weight, 27 081 (6%) for low physical activity, 14 474 (3%) for low dietary fiber intake, 9447 (2%) for low fruit and vegetable consumption, 9454 (2%) and 1687 (0.4%) for processed meat and high red meat consumption, respectively, and 1204 (0.3%) for high salt intake. Excess weight substantially contributed to endometrial, renal, and liver cancer (PAF = 24 to 35%). Low physical activity contributed to endometrial, renal, and lung cancer (PAF = 15 to 19%), and dietary factors mainly contributed to colorectal, breast, and lung cancer (PAF = 9 to 16%).

CONCLUSION

A considerable proportion of cancer cases are attributable to excess weight, physical inactivity, and unhealthy dietary habits. Major prevention efforts are needed to reduce the cancer incidence attributable to these avoidable factors.

Estimating the current and future cancer burden in Canada: methodological framework of the Canadian population attributable risk of cancer (ComPARe) study

INTRODUCTION

The Canadian Population Attributable Risk of Cancer project aims to quantify the number and proportion of cancer cases incident in Canada, now and projected to 2042, that could be prevented through changes in the prevalence of modifiable exposures associated with cancer. The broad risk factor categories of interest include tobacco, diet, energy imbalance, infectious diseases, hormonal therapies and environmental factors such as air pollution and residential radon.

METHODS AND ANALYSIS

Using a national network, we will use population-attributable risks (PAR) and potential impact fractions (PIF) to model both attributable (current) and avoidable (future) cancers. The latency periods and the temporal relationships between exposures and cancer diagnoses will be accounted for in the analyses. For PAR estimates, historical exposure prevalence data and the most recent provincial and national cancer incidence data will be used. For PIF estimates, we will model alternative or 'counterfactual' distributions of cancer risk factor exposures to assess how cancer incidence could be reduced under different scenarios of population exposure, projecting incidence to 2042.

DISSEMINATION

The framework provided can be readily extended and applied to other populations or jurisdictions outside of Canada. An embedded knowledge translation and exchange component of this study with our Canadian Cancer Society partners will ensure that these findings are translated to cancer programmes and policies aimed at population-based cancer risk reduction strategies.

The increasing burden of cancer attributable to high body mass index in Brazil

BACKGROUND

Body mass index (BMI) has been constantly increasing over the last decades in most parts of the world, most notably in transitioning nations such as Brazil. High BMI (>22 kg/m2) is associated with an increased risk of 14 types of cancer. We estimated the extent to which reducing high BMI could lower cancer incidence in Brazil, nationally as well as at regional and state levels.

METHODS

We calculated fractions of cancer incidence in 2012 attributable to high BMI as well as projections for attributable cases in 2025 using BMI data from representative national surveys and relative risks published in meta-analyses. Estimates of cancer incidence were retrieved from GLOBOCAN and the Brazilian National Cancer Institute.

RESULTS

We found that 15,465 (3.8%) of all new cancer cases diagnosed in Brazil in 2012 were attributable to high BMI, with a higher burden in women (5.2%) than in men (2.6%). The cancer sites contributing most to the number of attributable cases were breast (n = 4777), corpus uteri (n = 1729), and colon (n = 681) in women, and colon (n = 1062), prostate (n = 926), and liver (n = 651) in men. The highest population attributable fractions (PAFs) for all cancers were found in the richer states of the country, located in the south (1.5% men/3.4% women) and the southeast (1.5% men/3.3% women).

CONCLUSIONS

Cancer cases attributable to high BMI will reach 29,490, which will be 4.6% of all cancers in Brazil in 2025; the extent will be greater in women (6.2% or 18,837) than in men (3.2% or 10,653). This information is a tool to support policy makers for future cancer prevention strategies in Brazil.

Complex interplay among adiposity, insulin resistance and bone health

Obesity and osteoporosis are common public health problems. Paradoxically, while obesity is associated with higher bone density, type 2 diabetic obese individuals have an increased fracture risk. Although obesity and insulin resistance co-exist, some obese individuals remain insulin-sensitive. We suggest that the apparent paradox relating obesity, bone density and fracture risk in type 2 diabetes may be at least partly influenced by differences in bone strength and quality between insulin-resistant and insulin-sensitive obese individuals. In this review, we focus on the complex interplay between, adiposity, insulin resistance and osteoporotic fracture risk and suggest that this is an important area of study that has implications for individually tailored and targeted treatment to prevent osteoporotic fracture in obese type 2 diabetic individuals.

Gynaecological cancers and leptin: A focus on the endometrium and ovary

Obesity has an influence on the risk and prognosis of different types of cancers of the female reproductive tract. In the uterus, a common site for neoplasms is the endometrium, the inner lining tissue. Generally, obesity has been documented to be involved in endometrioid carcinoma of the endometrium. Obesity may influence the cancer risk by various mechanisms such as chronic inflammation, dysregulation of sex hormones and abnormal secretion of hormone-like cytokines or adipokines from adipose tissue. One of the important pro-inflammatory adipokines is leptin, which acts via its transmembrane receptors (Ob-R). In normal conditions, leptin functions in the hypothalamic anorexigenic pathway to maintain the energy homeostasis. Conversely, in obesity, leptin participates in the pro-inflammatory processes. Several clinical studies have suggested that leptin and Ob-R play a role in the pathological processes of endometrial cancer. In different endometrial cancer cell lines, laboratory findings also have demonstrated leptin's link to various neoplastic phenomena such as cellular proliferation, angiogenesis, and oestrogenic activity. Furthermore, endometrial cancer risk could be increased in ovarian pathology like polycystic ovary syndrome, which is commonly associated with obesity. It is noteworthy that leptin participates in both physiological and pathological conditions of the ovary. Leptin has shown pro-tumorigenic effects in both in-vitro and in-vivo studies. Generally, reduced serum leptin levels have been observed in ovarian cancer patients. However, overexpression of leptin and Ob-R in ovarian cancer tissue has indicated aggressive disease. Understanding the role of leptin-related intracellular signalling pathways in tumour development could be helpful in early cancer detection.

Viral infections and breast cancer - A current perspective

Sporadic human breast cancer is the most common cancer to afflict women. Since the discovery, decades ago, of the oncogenic mouse mammary tumour virus, there has been significant interest in the potential aetiologic role of infectious agents in sporadic human breast cancer. To address this, many studies have examined the presence of viruses (e.g. papillomaviruses, herpes viruses and retroviruses), endogenous retroviruses and more recently, microbes, as a means of implicating them in the aetiology of human breast cancer. Such studies have generated conflicting experimental and clinical reports of the role of infection in breast cancer. This review evaluates the current evidence for a productive oncogenic viral infection in human breast cancer, with a focus on the integration of sensitive and specific next generation sequencing technologies with pathogen discovery. Collectively, the majority of the recent literature using the more powerful next generation sequencing technologies fail to support an oncogenic viral infection being involved in disease causality in breast cancer. In balance, the weight of the current experimental evidence supports the conclusion that viral infection is unlikely to play a significant role in the aetiology of breast cancer.

Cancers in France in 2015 attributable to high body mass index

BACKGROUND

Overweight, as defined by high body mass index (BMI), is an established risk factor for various morbidities including cancer. Globally, its prevalence has increased markedly over the past decades. The aim of this study was to estimate the proportion and number of cancers that were attributable to high BMI in France in 2015.

METHODS

Population attributable fractions (PAFs) and numbers of cancer cases attributable to high BMI (a population mean BMI above the optimum of 22kg/m2) were estimated by age and sex, for cancer sites with convincing or probable evidence of an established causal link. Assuming a 10-year lag-period, PAFs were calculated using mean BMI estimates from a cross-sectional French population survey, and relative risk estimates from published meta-analyses.

RESULTS

An estimated 18,639 cancer cases diagnosed in France in 2015 were attributable to high BMI, corresponding to 5.3% of all cancer cases (6.7% in women and 4.1% in men). This included 4507 cases of postmenopausal breast and 3380 cases of colon cancer. The highest estimated PAFs were for oesophageal adenocarcinoma and corpus uteri cancer (37% and 34%, respectively).

CONCLUSION

High BMI is associated with a substantial number of cancer cases in France, a country with a low but increasing prevalence of overweight and obesity when compared to other European countries. Assuming that the association between high BMI and cancer is causal, these results highlight the need to prioritise the prevention of this risk factor as part of cancer control planning in France and elsewhere in Europe.

Cancers attributable to excess body weight in Canada in 2010

INTRODUCTION

Excess body weight (body mass index [BMI] ≥ 25.00 kg/m2) is an established risk factor for diabetes, hypertension and cardiovascular disease, but its relationship to cancer is lesser-known. This study used population attributable fractions (PAFs) to estimate the cancer burden attributable to excess body weight in Canadian adults (aged 25+ years) in 2010.

METHODS

We estimated PAFs using relative risk (RR) estimates from the World Cancer Research Fund International Continuous Update Project, BMI-based estimates of overweight (25.00 kg/m2-29.99 kg/m2) and obesity (30.00+ kg/m2) from the 2000-2001 Canadian Community Health Survey, and cancer case counts from the Canadian Cancer Registry. PAFs were based on BMI corrected for the bias in self-reported height and weight.

RESULTS

In Canada in 2010, an estimated 9645 cancer cases were attributable to excess body weight, representing 5.7% of all cancer cases (males 4.9%, females 6.5%). When limiting the analysis to types of cancer associated with high BMI, the PAF increased to 14.9% (males 17.5%, females 13.3%). Types of cancer with the highest PAFs were esophageal adenocarcinoma (42.2%), kidney (25.4%), gastric cardia (20.7%), liver (20.5%), colon (20.5%) and gallbladder (20.2%) for males, and esophageal adenocarcinoma (36.1%), uterus (35.2%), gallbladder (23.7%) and kidney (23.0%) for females. Types of cancer with the greatest number of attributable cases were colon (1445), kidney (780) and advanced prostate (515) for males, and uterus (1825), postmenopausal breast (1765) and colon (675) for females. Irrespective of sex or type of cancer, PAFs were highest in the Prairies (except Alberta) and the Atlantic region and lowest in British Columbia and Quebec.

CONCLUSION

The cancer burden attributable to excess body weight is substantial and will continue to rise in the near future because of the rising prevalence of overweight and obesity in Canada.

Cancer incidence attributable to excess body weight in Alberta in 2012

BACKGROUND

Excess body weight has been consistently associated with colorectal, breast, endometrial, esophageal, gall bladder, pancreatic and kidney cancers. The objective of this analysis was to estimate the proportion of total and site-specific cancers attributable to excess body weight in adults in Alberta in 2012.

METHODS

We estimated the proportions of attributable cancers using population attributable risk. Risk estimates were obtained from recent meta-analyses, and exposure prevalence estimates were obtained from the Canadian Community Health Survey. People with a body mass index of 25.00-29.99 kg/m2 and of 30 kg/m2 or more were categorized as overweight and obese, respectively.

RESULTS

About 14%-47% of men and 9%-35% of women in Alberta were classified as either overweight or obese; the proportion increased with increasing age for both sexes. We estimate that roughly 17% and 12% of obesity-related cancers among men and women, respectively, could be attributed to excess body weight in Alberta in 2012. The heaviest absolute burden in terms of number of cases was seen for breast cancer among women and for colorectal cancer among men. Overall, about 5% of all cancers in adults in Alberta in 2012 were estimated to be attributable to excess body weight in 2000-2003.

INTERPRETATION

Excess body weight contributes to a substantial proportion of cases of cancers associated with overweight and obesity annually in Alberta. Strategies to improve energy imbalance and reduce the proportion of obese and overweight Albertans may have a notable impact on cancer incidence in the future.

The fractions of cancer attributable to modifiable factors: A global review

Worldwide, the burden of cancer is rising, stimulating efforts to develop strategies to control these diseases. Primary prevention, a key control strategy, aims to reduce cancer incidence through programs directed towards reducing population exposure to known causal factors. Before enacting such strategies, it is necessary to estimate the likely effect on cancer incidence if exposures to known causal factors were reduced or eliminated. The population attributable fraction (PAF) is the epidemiological measure which quantifies this potential reduction in incidence. We surveyed the literature to document and summarise the proportions of cancers across the globe attributable to modifiable causes, specifically tobacco smoke, alcohol, overweight/obesity, insufficient physical activity, solar ultraviolet (UV) radiation and dietary factors (insufficient fruit, non-starchy vegetables and fibre; red/processed meat; salt). In total, we identified 55 articles that presented PAF estimates for one or more causes. Information coverage was not uniform, with many articles reporting cancer PAFs due to overweight/obesity, alcohol and tobacco, but fewer reporting PAFs for dietary factors or solar UV radiation. At all cancer sites attributable to tobacco and alcohol, median PAFs were markedly lower for women than men. Smoking contributed to very high median PAFs (>50%) for cancers of the lung and larynx. Median PAFs for men, attributable to alcohol, were high (25-50%) for cancers of the oesophagus, oral cavity/pharynx, larynx and liver. For cancers causally associated with overweight/obesity, high median PAFs were reported for oesophageal adenocarcinoma (men 29%, women 37%), gallbladder (men 11%, women 42%) and endometrium (36%). The cancer PAF literature is growing rapidly. Repeating this survey in the future should lead to more precise estimates of the potentially preventable fractions of cancer.

Cancers in Australia in 2010 attributable to modifiable factors: summary and conclusions

OBJECTIVE

To estimate the numbers and proportions of cancers occurring in Australia in 2010 attributable to modifiable causal factors.

METHODS

We estimated the population attributable fraction (PAF) of cancers associated with exposure to 13 causal factors using standard formulae incorporating exposure prevalence and relative risk data. We also calculated the potential impact of changing exposure to some factors.

RESULTS

A total of 32% of all cancers diagnosed in Australia in 2010 (excluding keratinocyte cancers) were attributable to the 13 factors assessed (men 33%; women 31%). Leading factors were tobacco smoke (PAF all cancers: 13.4%), solar radiation (6.2%), inadequate diet (6.1%) and overweight/obesity (3.4%). Factors conferring highest PAFs differed by sex: highest PAFs for men were tobacco smoke (15.8%), solar radiation (7.1%) and alcohol (3.0%); while highest PAFs for women were tobacco smoke (10.1%), solar radiation (5.0%) and overweight/obesity (4.5%). Sites with the highest counts of potentially preventable cancers were lung (8,569), colorectal (7,404), melanoma of the skin (7,220) and breast (3,233).

CONCLUSIONS

At least one in three cancers in Australia is attributable to exposure to known modifiable factors.

IMPLICATIONS

Up to 37,000 cancers could be prevented in Australia each year if the population avoided exposure to 13 common factors known or strongly suspected to cause cancer.

Body mass index and long-term risk of death from esophageal squamous cell carcinoma in a Chinese population

BACKGROUND

Studies based on Western populations have found that body mass index (BMI) is positively related to the risk of esophageal adenocarcinoma but inversely associated with esophageal squamous cell carcinoma (ESCC). Little reliable evidence exists of an association between BMI and ESCCin China, where ESCC incidence is high but BMI is low.

METHODS

We evaluated the BMI-ESCC association in a population-based prospective study of 29 446 Chinese aged 40-69 with 27 years of follow-up. China-specific BMI cut-offs (underweight < 18.5, healthy ≥ 18.5 to <24, overweight ≥ 24 to <28, and obese ≥ 28) and quartile categories were used to define BMI subgroups. Adjusted hazard ratios (HRs) and confidence intervals (CIs) for death from ESCC by BMI subgroups were calculated using Cox proportional hazards models.

RESULTS

During a median follow-up duration of 21.2 years (555 439 person-years), 2436 ESCC deaths were identified. BMI was protective for death from ESCC with an HR of 0.97 (95% CI 0.95-0.99) for each unit increase in BMI. Relative to healthy weight, HRs for BMI were 1.21 (95% CI 1.02-1.43) for the underweight group and 0.87 (95% CI 0.78-0.98) for the overweight. Categorical quartile analyses found people with BMIs in the Q3 and Q4 groups had 16% and 13% reductions in the risk of ESCC, respectively. Gender-specific analyses found that clear effects were evident in women only.

CONCLUSIONS

Higher BMI was associated with a reduced risk of ESCC in aChinese population.

NK cell count and glucotransporter 4 (GLUT4) expression in subjects with type 2 diabetes and colon cancer

BACKGROUND

Type 2 diabetes (T2D) and colon cancer (CC) are numbered among the most common diseases in the world. The decreased activity of natural killer (NK) cells previously revealed in both mentioned pathological states may be correlated with impaired expression of GLUT4 as the major insulin-dependent glucose transporter in these cells.

METHODS

The aim of this study was to evaluate GLUT4 expression and NK cells number in subjects with T2D and/or CC in comparison with control group. We evaluated 78 individuals divided into four groups: (1) patients with CC and T2DM, (2) patients with CC, (3) patients with T2DM (4) healthy control. GLUT4 expression on the surface of NK cells was measured using flow cytometry and phenotyping of NK cell was performed by immunofluorescent method.

RESULTS

Subjects with diabetes had the highest GLUT4 expression (21.35 ± 7.2 %) in comparison with other groups (P < 0.01). The mean values of GLUT4 expression in group with CC and in patients with both T2D and CC were similar (1.4 ± 0.4 % vs 1.5 ± 1.0 %; respectively). These values were significantly lower than in control group (12.6 ± 2.9 %; P < 0.01). In patients with T2D and CC the number of NK cells (20.15 ± 6.6 %) was significantly higher than in other groups, i.e. in group with T2D (14.08 ± 5.7 %), in group with CC (9.21 ± 3.6 %) and in control group (9.48 ± 4.7 %), respectively (P < 0.01).

CONCLUSIONS

It seems that there is a need to pay more attention to the high incidence of colon cancer among patients with type 2 diabetes. Decreased GLUT4 expression observed on NK cells in patients with colon cancer may be responsible for dysfunction of these cells and the higher carcinogenic risk in type 2 diabetic subjects.