Increasing colorectal cancer incidence trends among younger adults in Canada

Recent analyses in the United States have shown an overall decrease in the incidence of colorectal cancer despite contrasting increases in younger age groups. We examined whether these cohort trends are occurring in Canada. Age-specific trends in colon and rectal cancer incidence in Canada from the National Cancer Incidence Reporting System (1969-1992) and the Canadian Cancer Registry (1992-2012) were analyzed. We estimated annual percent changes (APC) with the Joinpoint Regression Program from the Surveillance Epidemiology, and End Results Program. Birth cohort effects were estimated using 5-year groups starting in 1888. Age-specific prevalence of class I, II and III obesity in Canada was examined from the National Population Health Survey (1994-2001) and the Canadian Community Health Survey (2001-2011). The reductions in CRC incidence among Canadians are limited to older populations. While reductions among younger age groups (20-29year olds (yo), 30-39yo and 40-50yo) were observed between 1969 and 1995, rates have returned to and surpassed historical levels (APCs 20-29yo colon cancer=6.24%, APCs 20-29yo rectal cancer=1.5%). Recent birth cohorts (1970-1990) have the highest incidence rate ratios ever recorded. Ecologic trends in obesity prevalence among these birth cohorts in Canada are suggestive of an impact on increasing incidence trends. Furthermore, obesity prevalence estimates suggest that these trends may continue to increase justifying further examination of the etiologic associations and biological impacts of excess adipose tissue among younger populations. While population-based screening of younger age groups deserves careful consideration, these concerning observed trends warrant public health action to address the growing obesity epidemic.

Alcohol consumption and low-risk drinking guidelines among adults: a cross-sectional analysis from Alberta's Tomorrow Project

INTRODUCTION

Moderate to heavy alcohol consumption is a risk factor for all-cause mortality and cancer incidence. Although cross-sectional data are available through national surveys, data on alcohol consumption in Alberta from a large prospective cohort were not previously available. The goal of these analyses was to characterize the levels of alcohol consumption among adults from the Alberta's Tomorrow Project in the context of cancer prevention guidelines. Furthermore, we conducted analyses to examine the relationships between alcohol consumption and other high-risk or risk-related behaviours.

METHODS

Between 2001 and 2009, 31 072 men and women aged 35 to 69 years were enrolled into Alberta's Tomorrow Project, a large provincial cohort study. Data concerning alcohol consumption in the past 12 months were obtained from 26 842 participants who completed self-administered health and lifestyle questionnaires. We conducted cross-sectional analyses on daily alcohol consumption and cancer prevention guidelines for alcohol use in relation to sociodemographic factors. We also examined the combined prevalence of alcohol consumption and tobacco use, obesity and comorbidities.

RESULTS

Approximately 14% of men and 12% of women reported alcohol consumption exceeding recommendations for cancer prevention. Higher alcohol consumption was reported in younger age groups, urban dwellers, those with higher incomes and those who consumed more red meat. Moreover, volume of daily alcohol consumption was positively associated with current tobacco use in both men and women. Overall, men were more likely to fall in the moderate and high-risk behavioural profiles and show higher daily alcohol consumption patterns compared to women.

CONCLUSION

Despite public health messages concerning the adverse impact of alcohol consumption, a sizeable proportion of Alberta's Tomorrow Project participants consumed alcohol in excess of cancer prevention recommendations. Continued strategies to promote low-risk drinking among those who choose to drink could impact future chronic disease risk in this population.

Measures of excess body weight and anthropometry among adult Albertans: cross-sectional results from Alberta's tomorrow project cohort

Background

Excess body weight during adulthood has been consistently associated with all-cause mortality, cardiovascular disease, and cancer at multiple sites among other chronic diseases. We describe the prevalence of excess body weight and abdominal obesity reported by participants enrolled in Alberta’s Tomorrow Project (ATP).

Methods

ATP is a geographically-based cohort study conducted among adults aged 35–69 years from across the province of Alberta. Participants completed anthropometric measures and health and lifestyle questionnaires at enrolment. Overweight and obese were categorized as a body mass index (BMI) of 25.0–29.9 kg/m² and ≥30 kg/m², respectively. Abdominal obesity was categorized using cut-offs of waist circumference of >94 cm for men and >80 cm for women and waist-tp-hip ratio cut-offs of >0.90 for men and >0.85 for women.

Results

BMI and hip and waist circumference data were obtained from 12,062 men and 18,853 women enrolled between 2001 and 2009. Overall, 76.8% of men and 59.5% of women reported a BMI ≥25 kg/m². The proportions of overweight and obese were significantly higher in older age groups (p < 0.001). In addition, the proportion of participants reporting being overweight and obese was higher among lower education (p < 0.001) and lower income groups (p < 0.001). Overall, approximately two thirds of men and women in ATP cohort reported abdominal obesity. Overweight, obesity and abdominal obesity were all associated with a history of several cardiometabolic chronic conditions including hypertension, heart attack, angina, high cholesterol, stroke and diabetes.

Conclusion

A large majority of ATP participants were overweight and carried excess abdominal fat. Strategies to improve energy balance among Albertans are encouraged and may have a notable impact on future chronic disease burden.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4887-2) contains supplementary material, which is available to authorized users.

A Systematic Review of the Effect of Lifestyle Interventions on Adipose Tissue Gene Expression: Implications for Carcinogenesis

OBJECTIVE

The mechanisms driving the associations between body weight and physical activity levels and multiple types of cancer are not yet well understood. The purpose of this review was to examine the effects of lifestyle interventions on proposed biomarkers of lifestyle and cancer risk at the level of adipose tissue in humans.

METHODS

Embase, MEDLINE, and CINAHL were searched by using keywords relating to exercise or diet interventions, adipose tissue biology, and outcomes of interest. Eligible studies included randomized clinical trials of exercise and/or dietary interventions in humans compared with control or other interventions, reporting the collection of subcutaneous abdominal adipose tissue.

RESULTS

Nineteen studies met criteria for inclusion. Eight studies modified dietary intake, five altered exercise levels, and six studies used a combination of both. Change in subcutaneous adipose tissue gene expression was most commonly observed with dietary weight loss, with a pattern of decrease in leptin, tumor necrosis factor alpha, and interleukin 6, along with an increase in adiponectin. There was limited change with exercise-only interventions or study arms.

CONCLUSIONS

Interventions leading to weight loss result in an altered gene expression of adipokines and inflammatory markers in subcutaneous adipose tissue, while less change in gene expression was noted with exercise alone.

Intake of dietary fibre and lifetime non-steroidal anti-inflammatory drug (NSAID) use and the incidence of colorectal polyps in a population screened for colorectal cancer

Background

There is suggestive evidence that increased intake of dietary fibre and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are generally associated with decreased colorectal cancer risk. However, the effects on precursors of colorectal cancer, such as adenomatous polyps, are mixed. We present the associations between dietary fibre intake and NSAID use on the presence and type of colorectal polyps in a screening population.

Methods

A cross-sectional study of 2548 individuals undergoing colonoscopy at the Forzani & MacPhail Colon Cancer Screening Centre (Calgary, Canada) was conducted. Dietary fibre intake and NSAID use were assessed using the Diet History Questionnaire I or II and the Health and Lifestyle Questionnaire. Colorectal outcomes were documented as a polyp or high-risk adenomatous polyp (HRAP; villous histology, high-grade dysplasia, ≥10 mm or ≥3 adenomas). Crude and ORs and 95% CIs were estimated using unconditional logistic regression.

Results

There were 1450 negative colonoscopies and 1098 patients with polyps, of which 189 patients had HRAPs. Total dietary fibre intake was associated with a decreased presence of HRAPs (OR=0.50, 95% CI: 0.29 to 0.86) when comparing the highest to lowest quartiles and was observed with both soluble (OR=0.51, 95% CI: 0.30 to 0.88) and insoluble (OR=0.51, 95% CI: 0.30 to 0.86) fibres. Ever use of NSAIDs was also inversely associated with HRAPs (OR=0.65, 95% CI: 0.47 to 0.89), observed with monthly (OR=0.60, 95% CI: 0.37 to 0.95) and daily (OR=0.53, 95% CI: 0.32 to 0.86) use.

Conclusions

Dietary fibre intake and NSAID use were associated with a decreased risk of having a HRAP at screening.

Physical activity does not alter prolactin levels in post-menopausal women: results from a dose-response randomized controlled trial

Background

Increased circulating levels of prolactin have been associated with increased risk of both in situ and invasive breast cancer. We investigated whether or not physical activity had a dose–response effect in lowering plasma levels of prolactin in postmenopausal women.

Methods

Four hundred previously inactive but healthy postmenopausal women aged 50–74 years of age were randomized to 150 or 300 min per week of aerobic physical activity in a year-long intervention. Prolactin was measured from fasting samples with a custom-plex multiplex assay.

Results

A high compared to moderate volume of physical activity did not reduce plasma prolactin levels in intention-to-treat (Treatment Effect Ratio (TER) 1.00, 95% Confidence Interval (CI) 0.95 – 1.06) or per-protocol analyses (TER 1.02, 95% CI 0.93 – 1.13).

Conclusions

It is unlikely that changes in prolactin levels mediate the reduced risk of breast cancer development in post-menopausal women associated with increased levels of physical activity.

Trial registration

clinicaltrials.gov identifier: NCT01435005.

Cancer incidence attributable to lifestyle and environmental factors in Alberta in 2012: summary of results

BACKGROUND

Estimates of the proportion of cancer cases that can be attributed to modifiable risk factors are not available for Canada and, more specifically, Alberta. The purpose of this study was to estimate the total proportion of cancer cases in Alberta in 2012 that could be attributed to a set of 24 modifiable lifestyle and environmental risk factors.

METHODS

We estimated summary population attributable risk estimates for 24 risk factors (smoking [both passive and active], overweight and obesity, inadequate physical activity, diet [inadequate fruit and vegetable consumption, inadequate fibre intake, excess red and processed meat consumption, salt consumption, inadequate calcium and vitamin D intake], alcohol, hormones [oral contraceptives and hormone therapy], infections [Epstein-Barr virus, hepatitis B and C viruses, human papillomavirus, Helicobacter pylori], air pollution, natural and artificial ultraviolet radiation, radon and water disinfection by-products) by combining population attributable risk estimates for each of the 24 factors that had been previously estimated. To account for the possibility that individual cancer cases were the result of a combination of multiple risk factors, we subtracted the population attributable risk for the first factor from 100% and then applied the population attributable risk for the second factor to the remaining proportion that was not attributable to the first factor. We repeated this process in sequential order for all relevant exposures.

RESULTS

Overall, an estimated 40.8% of cancer cases in Alberta in 2012 were attributable to modifiable lifestyle and environmental risk factors. The largest proportion of cancers were estimated to be attributable to tobacco smoking, physical inactivity and excess body weight. The summary population attributable risk estimate was slightly higher among women (42.4%) than among men (38.7%).

INTERPRETATION

About 41% of cancer cases in Alberta may be attributable to known modifiable lifestyle and environmental risk factors. Reducing the prevalence of these factors in the Alberta population has the potential to substantially reduce the provincial cancer burden.

Lung cancer incidence attributable to residential radon exposure in Alberta in 2012

BACKGROUND

Radon is carcinogenic, and exposure to radon has been shown to increase the risk of lung cancer. The objective of this study was to quantify the proportion and number of lung cancer cases in Alberta in 2012 that could be attributed to residential radon exposure.

METHODS

We estimated the population attributable risk of lung cancer for residential radon using radon exposure data from the Cross-Canada Survey of Radon Concentrations in Homes from 2009-2011 and data on all-cause and lung cancer mortality from Statistics Canada from 2008-2012. We used cancer incidence data from the Alberta Cancer Registry for 2012 to estimate the total number of lung cancers attributable to residential radon exposure. Estimates were also stratified by sex and smoking status.

RESULTS

The mean geometric residential radon level in Alberta in 2011 was 71.0 Bq/m3 (geometric standard deviation 2.14). Overall, an estimated 16.6% (95% confidence interval 9.4%-29.8%) of lung cancers were attributable to radon exposure, corresponding to 324 excess attributable cancer cases. The estimated population attributable risk of lung cancer due to radon exposure was higher among those who had never smoked (24.8%) than among ever smokers (15.6%). However, since only about 10% of cases of lung cancer occur in nonsmokers, the estimated total number of excess cases was higher for ever smokers (274) than for never smokers (48).

INTERPRETATION

With about 17% of lung cancer cases in Alberta in 2012 attributable to residential radon exposure, exposure reduction has the potential to substantially reduce Alberta's lung cancer burden. As such, home radon testing and remediation techniques represent important cancer prevention strategies.

Cancer incidence attributable to air pollution in Alberta in 2012

BACKGROUND

The International Agency for Research on Cancer has classified outdoor air pollution (fine particulate matter [PM2.5]) as a Group 1 lung carcinogen in humans. We aimed to estimate the proportion of lung cancer cases attributable to PM2.5 exposure in Alberta in 2012.

METHODS

Annual average concentrations of PM2.5 in 2011 for 22 communities across Alberta were extracted from the Clean Air Strategic Alliance Data Warehouse and were population-weighted across the province. Using 7.5 µg/m3 and 3.18 µg/m3 as the annual average theoretical minimum risk concentrations of PM2.5, we estimated the proportion of the population above this cut-off to determine the population attributable risk of lung cancer due to PM2.5 exposure.

RESULTS

The mean population-weighted concentration of PM2.5 for Alberta in 2011 was 10.03 µg/m3. We estimated relative risks of 1.02 and 1.06 for theoretical minimum risk PM2.5 concentration thresholds of 7.5 µg/m3 and 3.18 µg/m3, respectively. About 1.87%-5.69% of incident lung cancer cases in Alberta were estimated to be attributable to PM2.5 exposure.

INTERPRETATION

Our estimate of attributable burden is low compared to that reported in studies in other areas of the world owing to the relatively low levels of PM2.5 recorded in Alberta. Reducing PM2.5 emissions in Alberta should continue to be a priority to help decrease the burden of lung cancer in the population.

Cancer incidence attributable to inadequate physical activity in Alberta in 2012

BACKGROUND

Physical inactivity has been consistently associated with increased risk of colorectal, endometrial, breast (in postmenopausal women), prostate, lung and ovarian cancers. The objective of the current analysis was to estimate the proportion and absolute number of site-specific cancer cases attributable to inadequate physical activity in Alberta in 2012.

METHODS

We used population attributable risks to estimate the proportion of each site-specific cancer attributable to inactivity. Relative risk estimates were obtained from the epidemiological literature, and prevalence estimates were calculated with the use of data from the Canadian Community Health Survey cycle 2.1 (2003). Respondents who acquired 1.5-2.9 kcal/kg per day and less than 1.5 kcal/kg per day of physical activity were classified as moderately active and inactive, respectively, and both levels were considered inadequate for mitigating cancer risks. We obtained age-, sex- and site-specific cancer incidence data from the Alberta Cancer Registry for 2012.

RESULTS

About 59%-75% of men and 69%-78% of women did not engage in adequate physical activity. Overall, 13.8% of cancers across all associated cancers were estimated to be attributable to inadequate physical activity, representing 7.2% of all cancers diagnosed in Alberta in 2012. Suboptimal levels of physical activity had a greater impact among women: the proportion of all associated cancers attributable to inadequate physical activity was 18.3% for women and 9.9% for men.

INTERPRETATION

A substantial proportion of cancer cases diagnosed in Alberta were estimated to be attributable to inadequate physical activity. With the high prevalence of physical inactivity among adults in the province, developing strategies to increase physical activity levels could have a notable impact on reducing future cancer burden in Alberta.

Abstract B02: Recreational physical activity, sedentary time and the incidence of colorectal polyps in a screening population for colon cancer

Background: Despite the consistent association between regular recreational moderate to vigorous physical activity (rMVPA) and reduced risk of colorectal cancer (CRC), few studies have examined the effect of physical activity on carcinogenic development by examining colorectal adenomas (polyps). Furthermore, even fewer studies have examined the impact of sedentary behavior/time (ST) on the development of polyps. In this study we examined the associations between rMVPA and ST and the presence, number and type of colorectal polyps in a population undergoing screening for colorectal cancer in Calgary, Alberta, Canada.

Methods: A cross-sectional study of 2,499 individuals undergoing colonoscopy at the Forzani & MacPhail Colon Cancer Screening Centre in Calgary, Canada was conducted. Physical activity levels and ST were characterized using hours of rMVPA, meeting cancer prevention recommendations (≥150 mins/wk of rMVPA) and hours of ST using self-reported data from the Long Form International Physical Activity Questionnaire. Unconditional logistic regression models were used to estimate the crude and adjusted odds ratios (OR) for presence of polyps associated with rMVP and ST.

Results: Crude estimates for meeting cancer prevention guidelines (ORunadj=0.83, 95% CI: 0.70-0.98) and increasing rMVPA (ORunadj=0.75, 95% CI: 0.60-0.93 for 1-3 hrs/wk vs. 0) were associated with lower odds of having ≥1 polyp at screening. Effect estimates were attenuated in adjusted models. Threshold effects were observed for ST with significant associations observed for up to 20 hours/week of sitting time (ORadj per hour sitting=1.05, 95% CI: 1.01-1.09). Associations were strongest for rMVPA among females (ORadj=0.68, 95% CI: 0.48-0.97 for 1-3 hrs/wk vs. 0) and for ST among males (ORadj=1.74, 95% CI: 1.06-2.86 for 14-35hrs/wk of ST vs. 0-14 hrs/wk)

Conclusions: In this large population undergoing colonoscopy screening for colorectal cancer, rMVPA was associated with reduced prevalence of polyps at screening, particularly among females. Even low amounts of regular ST (2-5hrs/day) were associated with the presence of polyps, particularly among males. Strategies aimed at reducing the amount of pre-carcinogenic colon lesions should combine increasing rMVPA and reducing ST.

Citation Format: Darren R. Brenner, Demetra H. Yannitsos, Matthew Warkentin, Eileen Shaw, Nigel T. Brockton, S. Elizabeth McGregor, Susanna Town, Robert J. Hilsden. Recreational physical activity, sedentary time and the incidence of colorectal polyps in a screening population for colon cancer. [abstract]. In: Proceedings of the AACR Special Conference: Improving Cancer Risk Prediction for Prevention and Early Detection; Nov 16-19, 2016; Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(5 Suppl):Abstract nr B02.

Alcohol and lung cancer risk among never smokers: A pooled analysis from the international lung cancer consortium and the SYNERGY study

It is not clear whether alcohol consumption is associated with lung cancer risk. The relationship is likely confounded by smoking, complicating the interpretation of previous studies. We examined the association of alcohol consumption and lung cancer risk in a large pooled international sample, minimizing potential confounding of tobacco consumption by restricting analyses to never smokers. Our study included 22 case-control and cohort studies with a total of 2548 never-smoking lung cancer patients and 9362 never-smoking controls from North America, Europe and Asia within the International Lung Cancer Consortium (ILCCO) and SYNERGY Consortium. Alcohol consumption was categorized into amounts consumed (grams per day) and also modelled as a continuous variable using restricted cubic splines for potential non-linearity. Analyses by histologic sub-type were included. Associations by type of alcohol consumed (wine, beer and liquor) were also investigated. Alcohol consumption was inversely associated with lung cancer risk with evidence most strongly supporting lower risk for light and moderate drinkers relative to non-drinkers (>0-4.9 g per day: OR = 0.80, 95% CI = 0.70-0.90; 5-9.9 g per day: OR = 0.82, 95% CI = 0.69-0.99; 10-19.9 g per day: OR = 0.79, 95% CI = 0.65-0.96). Inverse associations were found for consumption of wine and liquor, but not beer. The results indicate that alcohol consumption is inversely associated with lung cancer risk, particularly among subjects with low to moderate consumption levels, and among wine and liquor drinkers, but not beer drinkers. Although our results should have no relevant bias from the confounding effect of smoking we cannot preclude that confounding by other factors contributed to the observed associations. Confounding in relation to the non-drinker reference category may be of particular importance.

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.

Dose–response effects of aerobic exercise on energy compensation in postmenopausal women: combined results from two randomized controlled trials

Background/objectives:

Despite the clear health benefits of exercise, exercised-induced weight loss is often less than expected. The term ‘exercise energy compensation’ is used to define the amount of weight loss below what is expected for the amount of exercise energy expenditure. We examined the dose–response effects of exercise volume on energy compensation in postmenopausal women.

Participants/methods:

Data from Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were combined for the present analysis. The ALPHA and BETA trials were two-centred, two-armed, 12-month randomized controlled trials. The ALPHA trial included 160 participants randomized to 225 min per week of aerobic exercise, and the BETA trial randomized 200 participants to each 150 and 300 min per week of aerobic exercise. All participants were aged 50–74 years, moderately inactive (<90 min per week of exercise), had no previous cancer diagnosis and a body mass index between 22 and 40 kg m⁻². Energy compensation was based on changes in body composition (dual-energy X-ray absorptiometry scan) and estimated exercise energy expenditure from completed exercise volume. Associations between Δenergy intake, ΔVO_2peak and Δphysical activity time with energy compensation were assessed.

Results:

No differences in energy compensation were noted between interventions. However, there were large inter-individual differences in energy compensation between participants; 9.4% experienced body composition changes that were greater than expected based on exercise energy expenditure, 64% experienced some degree of energy compensation and 26.6% experienced weight gain based on exercise energy expenditure. Increases in VO_2peak were associated with reductions in energy compensation (β=−3.44 ml kg⁻¹ min⁻¹, 95% confidence interval for β=−4.71 to −2.17 ml kg⁻¹ min⁻¹; P=0.0001).

Conclusions:

Large inter-individual differences in energy compensation were noted, despite no differences between activity doses. In addition, increases in VO_2peak were associated with lower energy compensation. Future studies are needed to identify behavioral and metabolic factors that may contribute to this large inter-individual variability in energy compensation.

Inflammatory Cytokines and Lung Cancer Risk in 3 Prospective Studies

To further investigate the role of inflammation in lung carcinogenesis, we evaluated associations between proinflammatory cytokines and lung cancer risk. We conducted a case-control study nested within 3 prospective cohort studies-the Melbourne Collaborative Cohort Study (1990-1994), the Malmö Diet and Cancer Study (1991-1996), and the Northern Sweden Health and Disease Study (initiated in 1985)-involving 807 incident lung cancer cases and 807 smoking-matched controls. Conditional logistic regression models adjusting for serum cotinine concentrations were used to estimate odds ratios for lung cancer risk associated with concentrations of interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12, interferon γ, tumor necrosis factor α, and granulocyte-macrophage colony-stimulating factor. We observed a higher lung cancer risk for participants with elevated concentrations of IL-6 and IL-8. These associations seemed to be stronger among former smokers (for fourth quartile vs. first quartile, odds ratio (OR) = 2.70, 95% confidence interval (CI): 1.55, 4.70) and current smokers (OR = 1.99, 95% CI: 1.15, 3.44) for IL-6 and among former smokers (OR = 2.83, 95% CI: 1.18, 6.75) and current smokers (OR = 1.30, 95% CI: 0.69, 2.44) for IL-8. No notable associations were observed among never smokers. Risk associations with IL-6 and IL-8 were observed for blood samples taken close to diagnosis (<5 years) as well as more than 15 years postdiagnosis.

Cancer incidence attributable to insufficient fibre consumption in Alberta in 2012

BACKGROUND

Insufficient fibre consumption has been associated with a increased risk of colorectal cancer. The purpose of this study was to estimate the proportion and absolute number of cancers in Alberta that could be attributed to insufficient fibre consumption in 2012.

METHODS

The number and proportion of colorectal cancers in Alberta attributable to insufficient fibre consumption were estimated using the population attributable risk. Relative risks were obtained from the World Cancer Research Fund's 2011 Continuous Update Project on colorectal cancer, and the prevalence of insufficient fibre consumption (< 23 g/d) was estimated using dietary data from Alberta's Tomorrow Project. Age- and sex-specific colorectal cancer incidence data for 2012 were obtained from the Alberta Cancer Registry.

RESULTS

Between 66% and 67% of men and between 73% and 78% of women reported a diet with insufficient fibre consumption. Population attributable risk estimates for colorectal cancer were marginally higher in men, ranging from 6.3% to 6.8% across age groups, whereas in women they ranged from 5.0% to 5.5%. Overall, 6.0% of colorectal cancers or 0.7% of all cancers in Alberta in 2012 were estimated to be attributable to insufficient fibre consumption.

INTERPRETATION

Insufficient fibre consumption accounted for 6.0% of colorectal cancers in Alberta in 2012. Increasing fibre consumption in Alberta has the potential to reduce to the future burden of colorectal cancer in the province.

Effects of exercise on markers of oxidative stress: an Ancillary analysis of the Alberta Physical Activity and Breast Cancer Prevention Trial

BACKGROUND

Oxidative stress may contribute to cancer aetiology through several mechanisms involving damage to DNA, proteins and lipids leading to genetic mutations and genomic instability. The objective of this study was to determine the effects of aerobic exercise on markers of oxidative damage and antioxidant enzymes in postmenopausal women.

METHODS

The Alberta Physical Activity and Breast Cancer Prevention Trial (ALPHA) was a two-centre, two-armed randomised trial of 320 inactive, healthy, postmenopausal women aged 50-74 years. Participants were randomly assigned to a year-long exercise intervention (225 min/week) or a control group while being asked to maintain a normal diet. Fasting blood samples were obtained and plasma concentrations of two oxidative damage markers (8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-isoprostaglandin F2α (8-Iso-PGF2α)) and two antioxidant enzymes (superoxide dismutase and catalase) were measured at baseline, 6 months and 12 months. Intention-to-treat (ITT) and per-protocol analyses were performed using linear mixed models adjusted for baseline biomarker concentrations. A further exercise adherence analysis, based on mean minutes of exercise per week, was also performed.

RESULTS

In the ITT and per-protocol analyses, the exercise intervention did not have any statistically significant effect on either oxidative damage biomarkers or antioxidant enzyme activity.

CONCLUSIONS

A year-long aerobic exercise intervention did not have a significant impact on oxidative stress in healthy, postmenopausal women.

TRIAL REGISTRATION NUMBER

NCT00522262.

Cancer incidence attributable to the use of oral contraceptives and hormone therapy in Alberta in 2012

BACKGROUND

Hormonal contraceptives and hormone replacement therapies are classified as carcinogenic to humans (group 1) by the International Agency for Research on Cancer. We sought to estimate the proportion and total number of cancers attributable to the use of oral contraceptives and hormone therapy in Alberta in 2012.

METHODS

Population attributable risks were used to estimate the proportion of attributable cases for each associated cancer site. Relative risk estimates were obtained from the most relevant and recent epidemiologic literature. Prevalences of the use of oral contraceptives and hormone therapy in Alberta were collected from Alberta's Tomorrow Project. Specific cancer incidence data were obtained from the Alberta Cancer Registry for the year 2012.

RESULTS

Overall, 6.3% of breast cancers (n = 135) diagnosed in Alberta in 2012 were estimated to be attributable to the use of oral contraceptives, and the exposure potentially prevented about 57.3% of endometrial cancers (n = 276) and 29.1% of ovarian cancers (n = 52). About 15.5% of breast cancers (n = 258) and 8.9% of ovarian cancers (n = 13) were estimated to be attributable to the use of hormone therapy, whereas 11.3% of endometrial cancers (n = 48) were possibly prevented by the exposure.

INTERPRETATION

Based on our estimates, oral contraceptive use resulted in a net protective effect among the cancer sites studied, thus reducing the cancer burden in Alberta in 2012. The use of hormone therapy was estimated to increase the cancer burden in the province, therefore the risk and benefit of hormone therapy should be carefully considered before use.

Cancer incidence attributable to insufficient fruit and vegetable consumption in Alberta in 2012

BACKGROUND

Sufficient fruit and vegetable consumption (≥ 5 servings/d) has been associated with a probable decreased risk for cancers of the oral cavity, pharynx, larynx, esophagus, stomach and lung (fruit only). The purpose of this study was to estimate the proportion and absolute number of cancer cases in Alberta in 2012 that were attributable to insufficient fruit and vegetable consumption.

METHODS

The numbers and proportions of cancers attributable to insufficient fruit and vegetable consumption were estimated using the population attributable risk. Relative risks were obtained from international collaborative panels and peer-reviewed literature. Prevalence data for insufficient fruit and vegetable consumption in Alberta were obtained from the Canadian Community Health Survey (2003, 2004, 2005, 2007/08). Age-, site- and sex-specific cancer incidence data for 2012 were obtained from the Alberta Cancer Registry.

RESULTS

The proportion of men consuming 5 or more servings of fruits and vegetables per day ranged from 25.9%-30.4% across age groups; the range among women was 46.8%-51.5% across age groups. The proportion of cancers attributable to insufficient fruit and vegetable consumption in Alberta was highest for esophageal cancer (40.0%) and lowest for lung cancer (3.3%). Overall, 290 cancer cases (1.8%) in Alberta in 2012 were attributable to insufficient fruit and vegetable consumption.

INTERPRETATION

Almost 2% of cancers in Alberta can be attributed to insufficient fruit and vegetable consumption. A diet rich in fruits and vegetables has benefits for the prevention of cancer and other chronic diseases; thus, increasing the proportion of Albertans who meet cancer prevention guidelines for fruit and vegetable consumption is a priority.

Cancer incidence attributable to red and processed meat consumption in Alberta in 2012

BACKGROUND

Consumption of red and processed meats has been associated with an increased risk of colorectal cancer. The purpose of this study was to estimate the proportion and absolute number of cancers in Alberta in 2012 that could be attributed to the consumption of red and processed meat.

METHODS

The number and proportion of colorectal cancers in Alberta that were attributable to red and processed meat consumption were estimated using population attributable risk. Relative risks were obtained from the World Cancer Research Fund's 2011 Continuous Update Project on Colorectal Cancer, and the prevalence of red and processed meat consumption was estimated using dietary data from Alberta's Tomorrow Project. Age- and sex-specific colorectal cancer incidence data for 2012 were obtained from the Alberta Cancer Registry.

RESULTS

Among participants in Alberta's Tomorrow Project, 41%-61% of men and 14%-25% of women consumed more than 500 g of red and processed meat per week, which exceeds World Cancer Research Fund cancer prevention guidelines. For red meat consumption, population attributable risks for colorectal cancer were substantially higher for men (13.6%-17.9%) than for women (1.6%-2.1%). For processed meat consumption, the population attributable risks were also higher for men (3.2%-4.8%) than for women (1.5%-2.1%). Overall, about 12% of colorectal cancers, or 1.5% of all cancers, in Alberta in 2012 were attributable to the consumption of red and processed meat.

INTERPRETATION

Red and processed meat consumption is estimated to acount for about 12% of colorectal cancers in Alberta. Decreasing its consumption has the potential to reduce to Alberta's cancer burden.

Cancer incidence attributable to tobacco in Alberta, Canada, in 2012

BACKGROUND

Strong and consistent epidemiologic evidence shows that tobacco smoking causes cancers at various sites. The purpose of this study was to quantify the proportion and total number of site-specific cancers in Alberta attributable to tobacco exposure.

METHODS

The proportion of incident cancer cases attributable to active and passive tobacco exposure in Alberta was estimated with population attributable risks. Data from the Canadian Community Health Survey (CCHS) for 2000-2007 were used to estimate prevalence of active (current or former smoker) and passive (second-hand smoke) tobacco exposure in Alberta.

RESULTS

According to the 2000/01 CCHS, 29.1% and 38.6% of Albertans were estimated to be current and former smokers, respectively. According to the 2003 CCHS, 23.7% of Albertans who had never smoked reported regular second-hand exposure to tobacco. Population attributable risk estimates for tobacco-related cancer sites ranged from about 4% for ovarian cancer to 74% for laryngeal cancer. About 5% of incident lung cancers in men and women who never smoked could be attributed to passive tobacco exposure. Overall, 37.0% of tobacco-related cancers in Alberta (or 15.7% of all cancers) were estimated to be attributable to active tobacco smoking in 2012.

INTERPRETATION

A notable proportion of cancers associated with tobacco use were estimated to be attributable to active smoking in Alberta. Strategies to reduce the prevalence of active tobacco smoking in Alberta could have a considerable impact on future cancer incidence.

Impact of aerobic exercise on levels of IL-4 and IL-10: results from two randomized intervention trials

The mechanisms whereby regular exercise reduces chronic inflammation remain unclear. We investigated whether regular aerobic exercise alters basal levels of interleukin (IL)‐10 and IL‐4 in two randomized trials of physical activity. The Alberta Physical Activity and Breast Cancer Prevention Trial (ALPHA, n = 320) and the Breast Cancer and Exercise Trial in Alberta (BETA, n = 400) were two‐center, two‐armed randomized trials in inactive, healthy, postmenopausal women. Both trials included an exercise intervention prescribed five times/week and no dietary changes. In ALPHA, the exercise group was prescribed 225 min/week versus no activity in the controls. BETA examined dose‐response effects comparing 300 (HIGH) versus 150 (MODERATE) min/week. Plasma concentrations of IL‐10 and IL‐4 were measured at baseline, 6, and 12 months. Intention‐to‐treat (ITT) analysis was performed using linear mixed models adjusted for baseline biomarker concentrations. Circulating anti‐inflammatory cytokine levels decreased among all groups, with percent change ranging from −3.4% (controls) to −8.2% (HIGH) for IL‐4 and −1.6% (controls) to −7.5% (HIGH) for IL‐10. No significant group differences were found for IL‐4 (ALPHA P = 0.54; BETA P = 0.32) or IL‐10 (ALPHA P = 0.84; BETA P = 0.68). Some evidence for moderation of the effect of exercise by baseline characteristics was found for IL‐10 but not for IL‐4. Results from these two large randomized aerobic exercise intervention trials suggest that aerobic exercise does not alter IL‐10 or IL‐4 in a manner consistent with chronic disease and cancer prevention.

A methodologic framework to evaluate the number of cancers attributable to lifestyle and environment in Alberta

BACKGROUND

Previous research to estimate population attributable risks for cancer in Alberta has been limited. Attributable burden estimates are important for planning and implementing population-based cancer prevention strategies. This article describes a methodologic framework to estimate the number of incident cancers attributable to modifiable lifestyle and environmental risk factors in Alberta.

METHODS

We estimated population attributable risks for cancer for exposures to 24 established cancer risk factors including tobacco consumption and environmental tobacco exposure, environmental factors, infectious agents, hormone therapies, dietary intake, obesity and physical inactivity. We used risk estimates to quantify the association between individual exposures and cancer sites as well as prevalence estimates for individual exposures in Alberta to estimate the proportion of cancer in Alberta that could be attributed to each exposure. These estimations were conducted in the context of a theoretical minimum risk principle, whereby exposures corresponding to the lowest levels of population risk were used as the comparisons for alternative exposure levels.

INTE RPRETATION

We outline the main methodologic principles for the protocol used in evaluating population attributable risks for modifiable lifestyle and environmental risk factors for cancer in Alberta. The data produced by this project will provide important information concerning which known cancer risk factors are responsible for the largest proportions of cancer in Alberta and could inform future cancer prevention strategies.

Cancer incidence attributable to alcohol consumption in Alberta in 2012

BACKGROUND

Alcohol consumption has been associated with risk of oral cavity/pharyngeal, laryngeal, esophageal, liver, colorectal and breast cancers. The purpose of this study was to estimate the proportion and total number of these cancers in Alberta in 2012 attributable to alcohol consumption.

METHODS

We estimated cancers attributable to alcohol consumption in adults in Alberta using population attributable risk calculations. Relative risks were obtained from recent meta-analyses, and alcohol consumption in Alberta was quantified with the use of data from the Canadian Community Health Survey. We obtained age-, site- and sex-specific cancer incidence data for 2012 from the Alberta Cancer Registry. The impact of potential underestimation of alcohol consumption in Canadian Community Health Survey data was evaluated with the use of per-capita alcohol sales data from Statistics Canada.

RESULTS

Proportions of cancers attributable to alcohol consumption at individual cancer sites were estimated to be as low as 5.1% (liver) and as high as 19.9% (oral cavity/pharynx) among men and as low as 2.1% (liver) and as high as 7.6% (oral cavity/pharynx) among women in Alberta. The total number of alcohol-attributable cancer cases was highest for common cancers (colorectal, female breast), whereas at individual cancer sites, population attributable risks were highest for upper aerodigestive tract cancers. A total of 4.8% of alcohol-associated cancers (1.6% of all cancers) in Alberta could be attributed to alcohol consumption. After adjustment for recorded alcohol consumption, our estimates of population attributable risk increased to 10.7% of alcohol-associated cancers and 3.5% of all cancers.

INTERPRETATION

Alcohol consumption is estimated to account for 1.6%-3.5% of total cancer cases in Alberta. Given that no level of alcohol consumption is considered safe with respect to cancer risk, strategies to reduce alcohol consumption have the potential to reduce Alberta's cancer burden.

Design, methods and demographics from phase I of Alberta's Tomorrow Project cohort: a prospective cohort profile

BACKGROUND

Prospective cohorts have the potential to support multifactorial, health-related research, particularly if they are drawn from the general population, incorporate active and passive follow-up and permission is obtained to allow access by researchers to data repositories. This paper describes Phase I of the Alberta's Tomorrow Project cohort, a broad-based research platform designed to support investigations into factors that influence cancer and chronic disease risk.

METHODS

Adults aged 35-69 years living in Alberta, Canada, with no previous cancer diagnosis other than nonmelanoma skin cancer were recruited to the project by telephone-based random digit dialling. Participants were enrolled if they returned a Health and Lifestyle Questionnaire. Past year diet and physical activity questionnaires were mailed 3 months after enrolment. Consent was sought for active follow-up and linkage with administrative databases. Depending on enrolment date, participants were invited to complete up to 2 follow-up questionnaires (2004 and 2008).

RESULTS

Between 2001 and 2009, 31 072 (39% men) participants (mean age 50.2 [± 9.2] yr) were enrolled and 99% consented to linkage with administrative databases. Participants reported a wide range of educational attainment and household income. Compared with provincial surveillance data from the Canadian Community Health Survey, Alberta's Tomorrow Project participants had higher body mass index, lower prevalence of smoking and similar distribution of chronic health conditions. Follow-up questionnaires were completed by 83% and 72% of participants in 2004 and 2008, respectively. Robust quality control measures resulted in low frequencies of missing data.

INTERPRETATION

Alberta's Tomorrow Project provides a robust platform, based on a prospective cohort design, to support research into risk factors for cancer and chronic disease.

Leisure-time physical activity and lung cancer risk: A systematic review and meta-analysis

OBJECTIVES

We conducted a systematic review and meta-analysis of the association between recreational physical activity and lung cancer risk to update previous analyses and to examine population subgroups of interest defined by smoking status and histology.

MATERIALS AND METHODS

We searched the PubMed database for studies up to May 2015. Individual study characteristics were abstracted including study design, number of cases, assessment of recreational physical activity and type and level of adjustment for confounding factors. Combined effect estimates were calculated for the overall associations and across subgroups of interest.

RESULTS

We identified 28 studies that were eligible for inclusion in the meta-analysis. The overall analysis indicated an inverse association between recreational physical activity and lung cancer risk (Relative Risk (RR), 0.76; 95% Confidence Interval (CI), 0.69-0.85, p-value: <0.001). Similar inverse associations with risk were also noted for all evaluated histological subtypes, including adenocarcinoma (RR, 0.80; 95% CI, 0.72-0.88), squamous (RR, 0.80; 95% CI, 0.71-0.90) and small cell (RR, 0.79; 95% CI, 0.66-0.94). When we examined effects by smoking status, inverse associations between recreational physical activity and lung cancer risk were observed among former (RR, 0.77; 95% CI, 0.69-0.85) and current smokers (RR, 0.77; 95% CI, 0.72-0.83), but not among never smokers (RR, 0.96; 95% CI, 0.79-1.18).

CONCLUSION

Results from this meta-analysis suggest that regular recreational physical activity may be associated with reduced risk of lung cancer. Only four studies examining never smokers were identified, suggesting the need for additional research in this population.

Breast cancer survival among young women: a review of the role of modifiable lifestyle factors

Almost 7 % of breast cancers are diagnosed among women age 40 years and younger in Western populations. Clinical outcomes among young women are worse. Early age-of-onset increases the risk of contralateral breast cancer, local and distant recurrence, and subsequent mortality. Breast cancers in young women (BCYW) are more likely to present with triple-negative (TNBC), TP53-positive, and HER-2 over-expressing tumors than among older women. However, despite these known differences in breast cancer outcomes and tumor subtypes, there is limited understanding of the basic biology, epidemiology, and optimal therapeutic strategies for BCYW. Several modifiable lifestyle factors associated with reduced risk of developing breast cancer have also been implicated in improved prognosis among breast cancer survivors of all ages. Given the treatment-related toxicities and the extended window for late effects, long-term lifestyle modifications potentially offer significant benefits to BCYW. In this review, we propose a model identifying three main areas of lifestyle factors (energy imbalance, inflammation, and dietary nutrient adequacy) that may influence survival in BCYW. In addition, we provide a summary of mechanisms of action and a synthesis of previous research on each of these topics.

Inflammatory Marker Changes in Postmenopausal Women after a Year-long Exercise Intervention Comparing High Versus Moderate Volumes

This randomized dose comparison trial examined if higher exercise volume decreased inflammatory biomarkers, associated with postmenopausal breast cancer risk, more than moderate exercise volume. The Breast Cancer and Exercise Trial in Alberta was a two-center, two-armed randomized trial in 400 inactive, healthy, postmenopausal women, aged 50 to 74 years, with a body mass index of 22 to 40 kg/m(2). Participants were randomized to high (300 minutes/week) or moderate (150 minutes/week) volumes of aerobic exercise while maintaining usual diet. Fasting blood concentrations of C-reactive protein (CRP), IL6, and TNFα were measured at baseline, 6 and 12 months. Intention-to-treat (ITT) analysis was performed using linear mixed models adjusted for baseline biomarker concentrations. ITT analyses of 386 (97%) participants showed no statistically significant group differences for changes in biomarker levels at 6 and 12 months. In addition, we did not observe any modification of this effect by baseline characteristics of participants. In post hoc analyses based on self-selected exercise level (measured in minutes/week), CRP decreased by 22.45% for participants who exercised >246 minutes/week (highest quintile) and increased by 0.07% for those who exercised <110 minutes/week (lowest quintile, Ptrend = 0.04), adjusted for baseline covariates. When this analysis was restricted to include exercise time in the target heart rate zone only, statistically significant trends were observed for both CRP (P < 0.01) and IL6 (P = 0.04). Prescribing 300 minutes/week of moderate-to-vigorous aerobic exercise did not improve inflammatory markers compared with 150 minutes/week in postmenopausal women. Decreases in CRP were observed with higher self-selected exercise volume.

Identification of lung cancer histology-specific variants applying Bayesian framework variant prioritization approaches within the TRICL and ILCCO consortia

Large-scale genome-wide association studies (GWAS) have likely uncovered all common variants at the GWAS significance level. Additional variants within the suggestive range (0.0001> P > 5×10(-8)) are, however, still of interest for identifying causal associations. This analysis aimed to apply novel variant prioritization approaches to identify additional lung cancer variants that may not reach the GWAS level. Effects were combined across studies with a total of 33456 controls and 6756 adenocarcinoma (AC; 13 studies), 5061 squamous cell carcinoma (SCC; 12 studies) and 2216 small cell lung cancer cases (9 studies). Based on prior information such as variant physical properties and functional significance, we applied stratified false discovery rates, hierarchical modeling and Bayesian false discovery probabilities for variant prioritization. We conducted a fine mapping analysis as validation of our methods by examining top-ranking novel variants in six independent populations with a total of 3128 cases and 2966 controls. Three novel loci in the suggestive range were identified based on our Bayesian framework analyses: KCNIP4 at 4p15.2 (rs6448050, P = 4.6×10(-7)) and MTMR2 at 11q21 (rs10501831, P = 3.1×10(-6)) with SCC, as well as GAREM at 18q12.1 (rs11662168, P = 3.4×10(-7)) with AC. Use of our prioritization methods validated two of the top three loci associated with SCC (P = 1.05×10(-4) for KCNIP4, represented by rs9799795) and AC (P = 2.16×10(-4) for GAREM, represented by rs3786309) in the independent fine mapping populations. This study highlights the utility of using prior functional data for sequence variants in prioritization analyses to search for robust signals in the suggestive range.

Alcohol consumption and the risk of renal cancers in the European prospective investigation into cancer and nutrition (EPIC)

Epidemiologic studies have reported that moderate alcohol consumption is inversely associated with the risk of renal cancer. However, there is no information available on the associations in renal cancer subsites. From 1992 through to 2010, 477,325 men and women in the European Prospective Investigation into Cancer and Nutrition cohort were followed for incident renal cancers (n = 931). Baseline and lifetime alcohol consumption was assessed by country-specific, validated dietary questionnaires. Information on past alcohol consumption was collected by lifestyle questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated from Cox proportional hazard models. In multivariate analysis, total alcohol consumption at baseline was inversely associated with renal cancer; the HR and 95% CI for the increasing categories of total alcohol consumption at recruitment versus the light drinkers category were 0.78 (0.62-0.99), 0.82 (0.64-1.04), 0.70 (0.55-0.90), 0.91 (0.63-1.30), respectively, (ptrend  = 0.001). A similar relationship was observed for average lifetime alcohol consumption and for all renal cancer subsites combined or for renal parenchyma subsite. The trend was not observed in hypertensive individuals and not significant in smokers. In conclusion, moderate alcohol consumption was associated with a decreased risk of renal cancer.

The Association between Leisure Time Physical Activity and Pancreatic Cancer Risk in Adults: A Systematic Review and Meta-analysis

We conducted a meta-analysis of the association between leisure time physical activity (LTPA) and risk of pancreatic cancer to update previous analyses in light of newly published studies, to examine subgroups of interest and potential sources of heterogeneity. We searched the PubMed and MEDLINE databases for studies until February 2015. Study information was collected using a standardized form to abstract relevant data on study design, number of cases, participant and study characteristics, assessment of LTPA, risk estimates, and adjustments for confounding by two independent abstractors. We used random-effects models to pool estimates from included studies of lowest versus highest comparison of LTPA. The search identified 26 studies eligible for inclusion into the meta-analysis. The combined summary risk estimate was [relative risk (RR), 0.89; 95% confidence interval (CI), 0.82-0.96]. There was evidence of heterogeneity across studies (I(2) = 22.1%, Pheterogeneity = 0.130). Some of the heterogeneity could be explained by study design, with stronger protective effects observed among case-control studies (RR, 0.69; 95% CI, 0.59-0.81) compared with cohort studies (RR, 0.96; 95% CI, 0.91-1.02). Across study designs, age of population was a source of heterogeneity, with stronger effects observed among younger (<50 years) populations. The present meta-analysis supports a protective association between LTPA and pancreatic cancer with an 11% risk reduction observed. LTPA appears to have the strongest effect among young populations. Additional investigations are needed to provide insights regarding the impact of LTPA in healthy adult populations, to reduce the risk of pancreatic cancer and encourage increases in LTPA.

The 12p13.33/RAD52 locus and genetic susceptibility to squamous cell cancers of upper aerodigestive tract

Genetic variants located within the 12p13.33/RAD52 locus have been associated with lung squamous cell carcinoma (LUSC). Here, within 5,947 UADT cancers and 7,789 controls from 9 different studies, we found rs10849605, a common intronic variant in RAD52, to be also associated with upper aerodigestive tract (UADT) squamous cell carcinoma cases (OR = 1.09, 95% CI: 1.04-1.15, p = 6x10(-4)). We additionally identified rs10849605 as a RAD52 cis-eQTL inUADT(p = 1x10(-3)) and LUSC (p = 9x10(-4)) tumours, with the UADT/LUSC risk allele correlated with increased RAD52 expression levels. The 12p13.33 locus, encompassing rs10849605/RAD52, was identified as a significant somatic focal copy number amplification in UADT(n = 374, q-value = 0.075) and LUSC (n = 464, q-value = 0.007) tumors and correlated with higher RAD52 tumor expression levels (p = 6x10(-48) and p = 3x10(-29) in UADT and LUSC, respectively). In combination, these results implicate increased RAD52 expression in both genetic susceptibility and tumorigenesis of UADT and LUSC tumors.

Olsson A. Is previous respiratory disease a risk factor for lung cancer?

RATIONALE

Previous respiratory diseases have been associated with increased risk of lung cancer. Respiratory conditions often co-occur and few studies have investigated multiple conditions simultaneously.

OBJECTIVES

Investigate lung cancer risk associated with chronic bronchitis, emphysema, tuberculosis, pneumonia, and asthma.

METHODS

The SYNERGY project pooled information on previous respiratory diseases from 12,739 case subjects and 14,945 control subjects from 7 case-control studies conducted in Europe and Canada. Multivariate logistic regression models were used to investigate the relationship between individual diseases adjusting for co-occurring conditions, and patterns of respiratory disease diagnoses and lung cancer. Analyses were stratified by sex, and adjusted for age, center, ever-employed in a high-risk occupation, education, smoking status, cigarette pack-years, and time since quitting smoking.

MEASUREMENTS AND MAIN RESULTS

Chronic bronchitis and emphysema were positively associated with lung cancer, after accounting for other respiratory diseases and smoking (e.g., in men: odds ratio [OR], 1.33; 95% confidence interval [CI], 1.20-1.48 and OR, 1.50; 95% CI, 1.21-1.87, respectively). A positive relationship was observed between lung cancer and pneumonia diagnosed 2 years or less before lung cancer (OR, 3.31; 95% CI, 2.33-4.70 for men), but not longer. Co-occurrence of chronic bronchitis and emphysema and/or pneumonia had a stronger positive association with lung cancer than chronic bronchitis "only." Asthma had an inverse association with lung cancer, the association being stronger with an asthma diagnosis 5 years or more before lung cancer compared with shorter.

CONCLUSIONS

Findings from this large international case-control consortium indicate that after accounting for co-occurring respiratory diseases, chronic bronchitis and emphysema continue to have a positive association with lung cancer.

Estimating and explaining the effect of education and income on head and neck cancer risk: INHANCE consortium pooled analysis of 31 case-control studies from 27 countries

Low socioeconomic status has been reported to be associated with head and neck cancer risk. However, previous studies have been too small to examine the associations by cancer subsite, age, sex, global region and calendar time and to explain the association in terms of behavioral risk factors. Individual participant data of 23,964 cases with head and neck cancer and 31,954 controls from 31 studies in 27 countries pooled with random effects models. Overall, low education was associated with an increased risk of head and neck cancer (OR = 2.50; 95% CI = 2.02 - 3.09). Overall one-third of the increased risk was not explained by differences in the distribution of cigarette smoking and alcohol behaviors; and it remained elevated among never users of tobacco and nondrinkers (OR = 1.61; 95% CI = 1.13 - 2.31). More of the estimated education effect was not explained by cigarette smoking and alcohol behaviors: in women than in men, in older than younger groups, in the oropharynx than in other sites, in South/Central America than in Europe/North America and was strongest in countries with greater income inequality. Similar findings were observed for the estimated effect of low versus high household income. The lowest levels of income and educational attainment were associated with more than 2-fold increased risk of head and neck cancer, which is not entirely explained by differences in the distributions of behavioral risk factors for these cancers and which varies across cancer sites, sexes, countries and country income inequality levels.

A review of the application of inflammatory biomarkers in epidemiologic cancer research

Inflammation is a facilitating process for multiple cancer types. It is believed to affect cancer development and progression through several etiologic pathways, including increased levels of DNA adduct formation, increased angiogenesis, and altered antiapoptotic signaling. This review highlights the application of inflammatory biomarkers in epidemiologic studies and discusses the various cellular mediators of inflammation characterizing the innate immune system response to infection and chronic insult from environmental factors. Included is a review of six classes of inflammation-related biomarkers: cytokines/chemokines, immune-related effectors, acute-phase proteins, reactive oxygen and nitrogen species, prostaglandins and cyclooxygenase-related factors, and mediators such as transcription factors and growth factors. For each of these biomarkers, we provide a brief overview of the etiologic role in the inflammation response and how they have been related to cancer etiology and progression within the literature. We provide a discussion of the common techniques available for quantification of each marker, including strengths, weaknesses, and potential pitfalls. Subsequently, we highlight a few under-studied measures to characterize the inflammatory response and their potential utility in epidemiologic studies of cancer. Finally, we suggest integrative methods for future studies to apply multifaceted approaches to examine the relationship between inflammatory markers and their roles in cancer development.

Physical activity and risk of pancreatic cancer in a central European multicenter case-control study

PURPOSE

Findings from epidemiological studies examining physical activity in relation to pancreatic cancer risk have suggested decreased risks for physical activity; however, the results are inconsistent.

METHODS

The association between occupational and leisure-time physical activity and risk of pancreatic cancer was examined among 826 pancreatic cancer cases and 930 age-, sex- and center-matched controls from a large multicenter central European study in Czech Republic and Slovakia recruited between 2004 and 2012. Data on physical activity including type and dose (frequency, intensity, and duration) were examined using multivariable-adjusted logistic regression models.

RESULTS

Occupational physical activity was not significantly associated with risk of pancreatic cancer [odds ratio (OR) 0.90, 95 % confidence interval (CI) 0.71-1.15]. A 35 % decrease in risk of pancreatic cancer was observed for regular leisure-time physical activity (OR 0.65, 95 % CI 0.52-0.87). The risk estimates were significant for low and moderate intensity of activity with the strongest protective effect among individuals who exercised during more than 40 weeks per year. The results for cumulated leisure-time physical activity assessed 1 year prior to diagnosis achieved the same level of risk reduction. In addition, stronger risk estimates for leisure-time physical activity were observed among women (men: OR 0.74, 95 % CI 0.54-1.01; women: OR 0.53, 95 % CI 0.37-0.75). The findings for female participants were stronger for intensity and frequency of leisure-time physical activity, in particular for light and moderate activity (OR 0.43, 95 % CI 0.25-0.75; and OR 0.57, 95 % CI 0.37-0.88, respectively).

CONCLUSION

These results provide evidence for a decreased risk of pancreatic cancer associated with regular leisure-time physical activity.

Previous lung diseases and lung cancer risk: a pooled analysis from the International Lung Cancer Consortium

To clarify the role of previous lung diseases (chronic bronchitis, emphysema, pneumonia, and tuberculosis) in the development of lung cancer, the authors conducted a pooled analysis of studies in the International Lung Cancer Consortium. Seventeen studies including 24,607 cases and 81,829 controls (noncases), mainly conducted in Europe and North America, were included (1984-2011). Using self-reported data on previous diagnoses of lung diseases, the authors derived study-specific effect estimates by means of logistic regression models or Cox proportional hazards models adjusted for age, sex, and cumulative tobacco smoking. Estimates were pooled using random-effects models. Analyses stratified by smoking status and histology were also conducted. A history of emphysema conferred a 2.44-fold increased risk of lung cancer (95% confidence interval (CI): 1.64, 3.62 (16 studies)). A history of chronic bronchitis conferred a relative risk of 1.47 (95% CI: 1.29, 1.68 (13 studies)). Tuberculosis (relative risk = 1.48, 95% CI: 1.17, 1.87 (16 studies)) and pneumonia (relative risk = 1.57, 95% CI: 1.22, 2.01 (12 studies)) were also associated with lung cancer risk. Among never smokers, elevated risks were observed for emphysema, pneumonia, and tuberculosis. These results suggest that previous lung diseases influence lung cancer risk independently of tobacco use and that these diseases are important for assessing individual risk.

Asthma and lung cancer risk: a systematic investigation by the International Lung Cancer Consortium

Asthma has been hypothesized to be associated with lung cancer (LC) risk. We conducted a pooled analysis of 16 studies in the International Lung Cancer Consortium (ILCCO) to quantitatively assess this association and compared the results with 36 previously published studies. In total, information from 585 444 individuals was used. Study-specific measures were combined using random effects models. A meta-regression and subgroup meta-analyses were performed to identify sources of heterogeneity. The overall LC relative risk (RR) associated with asthma was 1.28 [95% confidence intervals (CIs) = 1.16-1.41] but with large heterogeneity (I(2) = 73%, P < 0.001) between studies. Among ILCCO studies, an increased risk was found for squamous cell (RR = 1.69, 95%, CI = 1.26-2.26) and for small-cell carcinoma (RR = 1.71, 95% CI = 0.99-2.95) but was weaker for adenocarcinoma (RR = 1.09, 95% CI = 0.88-1.36). The increased LC risk was strongest in the 2 years after asthma diagnosis (RR = 2.13, 95% CI = 1.09-4.17) but subjects diagnosed with asthma over 10 years prior had no or little increased LC risk (RR = 1.10, 95% CI = 0.94-1.30). Because the increased incidence of LC was chiefly observed in small cell and squamous cell lung carcinomas, primarily within 2 years of asthma diagnosis and because the association was weak among never smokers, we conclude that the association may not reflect a causal effect of asthma on the risk of LC.

Dietary patterns and ethnicity are associated with distinct plasma proteomic groups

BACKGROUND

High-abundance plasma proteins are involved in disease-associated pathways and are useful in the diagnosis of nutritional and disease states. However, little is known about how concentrations of many plasma proteins vary between individuals from different ethnocultural groups with different dietary habits.

OBJECTIVE

We explored the association between plasma proteomic groups, dietary patterns, and ethnicity in the Toronto Nutrigenomics and Health Study, an ethnically diverse population of healthy young adults.

DESIGN

Concentrations of 54 high-abundance plasma proteins were measured simultaneously by liquid chromatography/multiple-reaction monitoring-mass spectrometry in 1090 individuals. Principal components analysis was used to identify plasma proteomic groups. Linear regression was used to investigate relations between proteomic groups and previously identified dietary patterns (Western, prudent, Eastern). Differences in individual protein concentrations between ethnocultural groups were tested by using general linear models.

RESULTS

Four independent principal components representative of proteomic groups were identified. Principal components 1 and 2 included proteins from multiple pathways. Component 3 was inflammatory, and component 4 included coagulation cascade proteins. East Asians and South Asians had lower component 1 scores, and East Asians had higher component 2 scores. South Asians had higher average scores for component 3. Individual protein concentrations also varied across ethnocultural groups. Principal component 1 was positively associated with the Western dietary pattern and inversely associated with the Eastern pattern. Component 3 was positively associated with the Eastern pattern.

CONCLUSIONS

Plasma proteomic groups differ between young adults of diverse ethnocultural groups with different dietary habits. These differences may partly account for different rates of cardiometabolic disease later in life.

Dietary patterns in an ethnoculturally diverse population of young Canadian adults

PURPOSE

Dietary patterns of food consumption were investigated among young urban Toronto adults, including men and women from different ethnocultural groups.

METHODS

We performed a cross-sectional analysis among 1153 adults aged 20 to 29 years, from the Toronto Nutrigenomics and Health Study. Principal components analysis of food intake scores was used to identify food consumption patterns. Logistic regression, analysis of variance, and t-tests were used to test for differences in dietary patterns between ethnocultural groups and between men and women. Partial correlations were used to investigate the relationship between patterns and nutrient intake.

RESULTS

Three predominant patterns were identified and termed "prudent," "Western," and "Eastern" patterns. Caucasians had significantly higher prudent pattern scores than did Asians and South Asians, while Asians had significantly higher Eastern pattern scores than did other ethnocultural groups (p<0.01). Women had higher prudent pattern scores (odds ratio [OR]=4.31, 95% confidence interval [CI]=3.11-5.96) and lower Western pattern scores (OR=0.62, 95% CI=0.45-0.84) than did men. Dietary pattern scores were correlated with nutrient and energy intakes.

CONCLUSIONS

We observed distinct dietary patterns in this population of young adults. These dietary patterns varied significantly between ethnocultural groups and between men and women. The patterns were associated with nutrient intake levels; this association may have important public health implications.

Plasma vitamin D levels and risk of metabolic syndrome in Canadians

Purpose: Vitamin D deficiency has been implicated in susceptibility to the development of metabolic syndrome, obesity and type 2 diabetes mellitus. The present study aimed to quantify the association between vitamin D plasma level, the number of metabolic syndrome components and insulin resistance in Canadians. Methods: Vitamin D plasma level and clinical data were determined from 1,818 subjects from the Canadian Health Measures Survey; a representative health survey of the general population of Canada conducted from 2007 to 2009. The definition of metabolic syndrome was based on the National Cholesterol Education Program, Adult Treatment Panel III criteria. Adjusted general linear models were used to estimate the association between vitamin D level and probability of having metabolic syndrome, as well as the association between plasma vitamin D and insulin resistance (homeostasis model assessment for insulin resistance, or HOMA-IR). Results: The prevalence of metabolic syndrome in the study population was 8.9%. The number of metabolic syndrome components was inversely correlated with plasma vitamin D level (ρ= -0.1, p < 0.0001). Subjects in the highest vitamin D quartile had lower odds ratio of metabolic syndrome compared with their counterparts in the lowest vitamin D quartile (0.50, 95% CI= 0.24-1.06). Increasing plasma vitamin D level (by 10 nmol/L) was inversely associated with HOMA-IR score (β= -0.08, p=0.006) in a model adjusted for physical activity, smoking status, month of interview, age, sex and ethnicity. Conclusion: Vitamin D plasma levels are associated with the occurrence of metabolic syndrome components and insulin resistance among Canadians and are linked to increased level of insulin resistance.

Previous lung diseases and lung cancer risk: a systematic review and meta-analysis

BACKGROUND

In order to review the epidemiologic evidence concerning previous lung diseases as risk factors for lung cancer, a meta-analysis and systematic review was conducted.

METHODS

Relevant studies were identified through MEDLINE searches. Using random effects models, summary effects of specific previous conditions were evaluated separately and combined. Stratified analyses were conducted based on smoking status, gender, control sources and continent.

RESULTS

A previous history of COPD, chronic bronchitis or emphysema conferred relative risks (RR) of 2.22 (95% confidence interval (CI): 1.66, 2.97) (from 16 studies), 1.52 (95% CI: 1.25, 1.84) (from 23 studies) and 2.04 (95% CI: 1.72, 2.41) (from 20 studies), respectively, and for all these diseases combined 1.80 (95% CI: 1.60, 2.11) (from 39 studies). The RR of lung cancer for subjects with a previous history of pneumonia was 1.43 (95% CI: 1.22-1.68) (from 22 studies) and for subjects with a previous history of tuberculosis was 1.76 (95% CI=1.49, 2.08), (from 30 studies). Effects were attenuated when restricting analysis to never smokers only for COPD/emphysema/chronic bronchitis (RR=1.22, 0.97-1.53), however remained significant for pneumonia 1.36 (95% CI: 1.10, 1.69) (from 8 studies) and tuberculosis 1.90 (95% CI: 1.45, 2.50) (from 11 studies).

CONCLUSIONS

Previous lung diseases are associated with an increased risk of lung cancer with the evidence among never smokers supporting a direct relationship between previous lung diseases and lung cancer.

A population-based case-control study of occupational exposure to acids and the risk of lung cancer: evidence for specificity of association

Occupational exposure to strong inorganic acid mists containing sulfuric acid has been recognized as a carcinogen (Group 1) since 1992. An augmented, secondary data analysis of a population-based case-control study of lung cancer was conducted to assess lung cancer-specific risks using 772 lung cancer cases diagnosed between 1981 and 1985. Individually matched controls--on age, gender, and borough of residence--were identified. Lifetime exposure to 10 acidic agents, including strong inorganic acids and some gases, was assessed from complete lifetime occupational histories in terms of concentration, frequency, and reliability of the various exposure assessments. Smoking-adjusted odds ratios and 95% confidence intervals were determined for overall and histology-categorized lung cancers using conditional logistic regression. No excess risk for overall lung cancer was associated with any of the acids, and effect modification by gender could not be identified. The absence of an acid lung cancer effect reinforces more recent toxicological data that suggest specificity to the larynx.

Lung cancer risk in never-smokers: a population-based case-control study of epidemiologic risk factors

BACKGROUND

We conducted a case-control study in the greater Toronto area to evaluate potential lung cancer risk factors including environmental tobacco smoke (ETS) exposure, family history of cancer, indoor air pollution, workplace exposures and history of previous respiratory diseases with special consideration given to never smokers.

METHODS

445 cases (35% of which were never smokers oversampled by design) between the ages of 20-84 were identified through four major tertiary care hospitals in metropolitan Toronto between 1997 and 2002 and were frequency matched on sex and ethnicity with 425 population controls and 523 hospital controls. Unconditional logistic regression models were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) for the associations between exposures and lung cancer risk.

RESULTS

Any previous exposure to occupational exposures (OR total population 1.6, 95% CI 1.4-2.1, OR never smokers 2.1, 95% CI 1.3-3.3), a previous diagnosis of emphysema in the total population (OR 4.8, 95% CI 2.0-11.1) or a first degree family member with a previous cancer diagnosis before age 50 among never smokers (OR 1.8, 95% CI 1.0-3.2) were associated with increased lung cancer risk.

CONCLUSIONS

Occupational exposures and family history of cancer with young onset were important risk factors among never smokers.

Comparison of body mass index and waist circumference as predictors of cardiometabolic health in a population of young Canadian adults

BACKGROUND

This study aimed to investigate whether waist circumference (WC) or body mass index (BMI) is a better predictor of blood lipid concentrations among young men and women from different ethnocultural groups.

METHODS

Participants were 1181 healthy men (n = 358) and women (n = 823) aged 20-29 years taken from the cross-sectional Toronto Nutrigenomics and Health Study. Analyses were conducted separately for men and women, and for Caucasian and East Asian ethnocultural groups. Serum triglycerides (TG) and total to HDL cholesterol ratio (TC:HDL cholesterol) were used as outcomes. Associations between the adiposity and blood lipid measures were examined using partial correlations and odds ratios derived from logistic regression models.

RESULTS

WC had a stronger association with serum lipid concentrations than BMI. WC was significantly related to TG and TC:HDL cholesterol after adjusting for BMI and covariates among men and women (P

CONCLUSIONS

WC is a stronger predictor of cardiometabolic health when compared with BMI among young adults, especially among men.

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