The individual and combined effects of alcohol consumption and cigarette smoking on site-specific cancer risk in a prospective cohort of 26,607 adults: results from Alberta's Tomorrow Project.

PURPOSE: Alcohol consumption and cigarette smoking increase the risk of developing several cancers. We examined the individual and synergistic effects of these modifiable lifestyle factors on overall and site-specific cancer risk. METHODS: Baseline participant data were acquired from Alberta's Tomorrow Project (ATP). Adults 35-69 years old who consented to data linkage and completed relevant questionnaires were included (n = 26,607). Incident cases of cancer up to December 2017 were identified via linkage to the Alberta Cancer Registry. Associations between alcohol consumption, cigarette smoking, and cancer risk were examined using adjusted Cox proportional hazard models. Non-linear effects were estimated using restricted cubic splines. Interactions between alcohol and tobacco were examined through stratified analyses and inclusion of interaction terms in relevant models. RESULTS: A total of 2,370 participants developed cancer during the study follow-up period. Cox proportional hazard models found no statistically significant associations between alcohol consumption and incidence of all cancers among males (hazard ratio [HR] 1.14, 95% confidence interval [CI] 0.93-1.40) and females ([HR] 0.89, 95% confidence interval [CI] 0.73-1.10), though a modest and positive association was observed in both males and the entire cohort using cubic splines. Smokers were at an increased risk of developing all cancers (female current smokers: [HR] 1.72, 95% [CI] 1.49-1.99, male current smokers: [HR] 1.24, 95% [CI] 1.03-1.49) with the strongest association observed between current smokers and lung cancer (males: [HR] 11.33, 95% [CI] 4.70-27.30, females: [HR] 23.51, 95% [CI] 12.70-43.60). A 3-way interaction model showed an additive effect between alcohol as a continuous variable (g/day) and pack-years (PYs) consumed for all, colon, and prostate cancers. A "U-shaped" multiplicative interaction was observed for breast cancer (p = 0.05). CONCLUSIONS: Alcohol consumption was minimally associated with all-cancer risk. Cigarette smoking clearly increased all-cancer risk, with females being more affected than males. Combined use of alcohol and tobacco increased the risk of developing all, colon, and prostate cancers. A "U-shaped" multiplicative interaction was observed for breast cancer when alcohol and tobacco were used in combination.

Estimates of the current and future burden of cancer attributable to lack of physical activity in Canada.

Physical activity reduces the risk of many cancers, yet the prevalence of inadequate physical activity among Canadians remains high. Here we estimated the current attributable and future avoidable burden of cancer related to inadequate physical activity among Canadian adults. Population attributable risk (PAR) for all cancers associated with inadequate physical activity were estimated using relative risks obtained from comprehensive reports, meta-analyses and pooled analyses. Cancer incidence data were acquired from the Canadian Cancer Registry. Physical activity data were taken from Canadian Community Health Survey (Cycle 2.1, 2003), in which respondents were classified as "physically inactive" (<1.5 kcal/kg/day), "moderately active" (1.5-2.9 kcal/kg/day) or "physically active (≥3.0 kcal/kg/day). We defined "inadequate physical activity" as being either "physically inactive" or "moderately active" to determine the PAR of cancer due to inadequate physical activity. We estimated the future burden of inadequate physical activity using potential impact fractions and a series of intervention scenarios, including 10% to 50% reductions in inadequate physical activity from 2015 to 2042. For 2015, the total attributable burden due to inadequate physical activity for associated cancers was 10.6% and 4.9% for all cancers. A 50% reduction in inadequate physical activity could avoid 39,877 cumulative cases of cancer by 2042. Over 9000 cancer cases in 2015 were estimated to be attributable to inadequate physical activity and 5170 incident cases of cancer could be prevented with increases in physical activity levels by 2042. Policies aimed at increasing physical activity among Canadian could have a meaningful impact for cancer prevention.

Estimates of the current and future burden of cancer attributable to sedentary behavior in Canada.

Leisure-time sedentary behavior is an emerging modifiable risk factor for cancer. We estimated the proportion of cancers attributed to leisure-time sedentary behavior as a separate risk factor from physical activity in Canada for 2015. We projected numbers of future avoidable cancers by 2042 using various assumed levels of reduced leisure-time sedentary behavior in the population. We calculated population attributable risks (PAR) for associated cancers and all-cancers associated with leisure-time sedentary behavior. Our analysis used pooled data on leisure-time sedentary behavior from the Canadian Community Health Survey (CCHS), and incident cancer data from the Canadian Cancer Registry (CCR). Survey respondents were categorized into three levels of leisure-time sedentary behavior, "<3 h/day", "≥3-<6 h/day", and "≥6 h/day". Estimates for the future burden of leisure-time sedentary behavior were calculated using the potential impact fractions framework (PIF) and counterfactual scenarios, from 10% to 50% decreases in leisure-time sedentary behavior. The estimated prevalence of leisure-time sedentary behavior at the highest level (≥6 h/day) in Canada during the 2000s was 9.9% among both sexes combined across age-groups. The total attributable burden due to leisure-time sedentary behavior was estimated to be 10.3% for associated cancers and 6.5% for all-cancers in 2015. A 50% reduction in leisure-time sedentary behavior across the Canadian population could avoid 4054 cancers by 2042. We estimated that over 3000 cancer cases in Canada were attributable to leisure-time sedentary behavior in 2015, and that that 4054 incident cancer cases could be prevented by 2042 with meaningful reductions in leisure-time sedentary behavior.

Central body fatness is a stronger predictor of cancer risk than overall body size.

The importance of body size versus weight distribution for cancer risk is unclear. We investigated associations between measures of body size and shape and the risk of developing cancer. The study population consisted of 26,607 participants from the Alberta's Tomorrow Project cohort. Two main measures of body shape and size were examined: i) body mass index (BMI) and ii) waist circumference (WC). Incident cancers were identified via linkage to the Alberta Cancer Registry. Cox proportional hazards models were used. Males and females classified as obese (BMI ≥ 30 kg /m-2) have a 33% and 22% increased risk of all-cancer, respectively, than their normal weight counterparts. Similar all-cancer risk increases are observed for those above sex-specific WC guidelines. Mutual adjustment for WC attenuates the association between BMI and all-cancer risk, especially among females. Central adiposity appears to be a stronger predictor of all-cancer risk than body size.

Sleep and cancer incidence in Alberta's Tomorrow Project cohort.

STUDY OBJECTIVES: Few studies have examined associations between sleep duration with combined and site-specific cancers within the same cohort. Additionally, no study to date has assessed associations between sleep timing midpoint and cancer incidence. Therefore, we aimed to investigate associations between self-reported sleep duration and sleep timing midpoint with combined and site-specific cancer incidence in Alberta's Tomorrow Project (ATP) cohort. METHODS: The sleep duration analysis included 45,984 Albertans aged 35-69 years recruited from 2001-2015. Sleep timing midpoint (wake-time - ½ sleep duration) was assessed in a subset of ATP participants (n = 19,822). Incident cancer cases were determined through linkage with the Alberta Cancer Registry in June 2017. Cox proportional hazard regression models evaluated the effects of sleep duration and sleep timing midpoint on combined and seven site-specific cancers. RESULTS: A total of 2,428 and 1,322 incident cancer cases were observed in the sleep duration and sleep timing analyses, respectively. Reporting >9 h of sleep/night versus 7-9 h of sleep/night was associated with an increased incidence of non-Hodgkin lymphoma (hazard ratio [HR] = 2.14, 95% confidence interval [CI]: 1.14-4.01; p = 0.02) and hematological (HR = 1.70, 95% CI: 1.03-2.82; p = 0.04) cancers. A later sleep timing midpoint (>4 h 8 min) versus an intermediate sleep timing midpoint (3 h 47 min-4 h 8 min) was associated with an increased incidence of combined (HR = 1.20, 95% CI: 1.04-1.37; p = 0.01) and breast (HR = 1.49, 95% CI: 1.09-2.03; p = 0.01) cancers. CONCLUSIONS: Sleep duration and sleep timing may play a role in cancer etiology. Studies including objective sleep assessments are needed to corroborate these findings.

Physical Activity and Cancer Incidence in Alberta's Tomorrow Project: Results from a Prospective Cohort of 26,538 Participants.

Background: Physical activity (PA) has been associated with lower risks of several cancers. We examined the association between total and domain-specific PA and risk of all and site-specific cancer risk.Methods: We analyzed baseline data from Alberta's Tomorrow Project. Specifically, adults ages 35-69 years who completed the Past Year Total Physical Activity Questionnaire were included (n = 26,538). For each activity, participants reported the type, duration, and intensity of PA. Total, recreational, and occupational PA metabolic equivalent hours/week were divided into quartiles. Incident cancer cases up to December 2016 were identified via linkage to the Alberta Cancer Registry. The associations of PA on cancer risk were examined using Cox proportional hazards models.Results: A total of 2,186 participants (8.24%) developed cancer during follow-up from 2001 to 2016. We observed a significant inverse association between total PA and all-cancer incidence in the multivariate-adjusted model [HRQ4vQ1 = 0.87; 95% confidence interval (CI): 0.76-0.99] that remained significant in the latency multivariate-adjusted model. Higher recreational PA was associated with a risk decrease for all-cancer in the latency multivariate-adjusted model (HR = 0.84; 95% CI: 0.74-0.96), and showed a linear inverse association with breast cancer. While none of the HR estimates for quartiles of occupational PA and all-cancer reached statistical significance, the model Ptrend was marginally significant in the latency multivariate-adjusted model (P = 0.06).Conclusions: In this cohort of Albertans, higher total PA and recreational PA appears to convey modest protection against the development of all-cancer.Impact: Public health and cancer prevention efforts should focus on encouraging population-level increases in PA. Cancer Epidemiol Biomarkers Prev; 27(8); 945-54. ©2018 AACR.

Fluoride exposure and reported learning disability diagnosis among Canadian children: Implications for community water fluoridation.

OBJECTIVES: Recent studies have connected increased fluoride exposure with increased risk of neurodevelopmental-related outcomes, such as ADHD (attention deficit hyperactivity disorder) and lower IQ in children. Our primary objective was to examine the association between fluoride exposure and reported diagnosis of a learning disability among a population-based sample of Canadian children aged 3-12 years. METHODS: We analyzed data from Cycles 2 and 3 of the Canadian Health Measures Survey. Four measures of fluoride exposure were available: 1) urinary fluoride (µmol/L), 2) creatinine-adjusted urinary fluoride (µmol/mmol), 3) specific gravity-adjusted urinary fluoride (µmol/L), and 4) fluoride concentration of tap water (mg/L) (Cycle 3 only). Diagnosis of a learning disability (yes/no) was based on parental- or self-report. Associations were examined using logistic regression (where possible), unadjusted and adjusted for covariates. RESULTS: When Cycles 2 and 3 were examined separately, reported learning disability diagnosis was not significantly associated with any measure of fluoride exposure in unadjusted or adjusted models. When Cycles 2 and 3 were combined, a small but statistically significant effect was observed such that children with higher urinary fluoride had higher odds of having a reported learning disability in the adjusted model (p = 0.03). However, the association was not observed in models that used creatinine-adjusted urinary fluoride and specific gravity-adjusted urinary fluoride, which are believed to be more accurate measures due to their correction for urinary dilution. CONCLUSION: Overall, there did not appear to be a robust association between fluoride exposure and parental- or self-reported diagnosis of a learning disability among Canadian children.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation.

BACKGROUND: There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. METHODS: We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. RESULTS: There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. CONCLUSION: These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist.

Population-level interventions in government jurisdictions for dietary sodium reduction: a Cochrane Review.

Background: Worldwide, excessive salt consumption is common and is a leading cause of high blood pressure. Our objectives were to assess the overall and differential impact (by social and economic indicators) of population-level interventions for dietary sodium reduction in government jurisdictions worldwide. Methods: This is a Cochrane systematic review. We searched nine peer-reviewed databases, seven grey literature resources and contacted national programme leaders. We appraised studies using an adapted version of the Cochrane risk of bias tool. To assess impact, we computed the mean change in salt intake (g/day) from before to after intervention. Results: Fifteen initiatives met the inclusion criteria and 10 provided sufficient data for quantitative analysis of impact. Of these, five showed a mean decrease in salt intake from before to after intervention including: China, Finland (Kuopio area), France, Ireland and the UK. When the sample was constrained to the seven initiatives that were multicomponent and incorporated activities of a structural nature (e.g. procurement policy), most (4/7) showed a mean decrease in salt intake. A reduction in salt intake was more apparent among men than women. There was insufficient information to assess differential impact by other social and economic axes. Although many initiatives had methodological strengths, all scored as having a high risk of bias reflecting the observational design. Study heterogeneity was high, reflecting different contexts and initiative characteristics. Conclusions: Population-level dietary sodium reduction initiatives have the potential to reduce dietary salt intake, especially if they are multicomponent and incorporate intervention activities of a structural nature. It is important to consider data infrastructure to permit monitoring of these initiatives.

Population-level interventions in government jurisdictions for dietary sodium reduction.

BACKGROUND: Excess dietary sodium consumption is a risk factor for high blood pressure, stroke and cardiovascular disease. Currently, dietary sodium consumption in almost every country is too high. Excess sodium intake is associated with high blood pressure, which is common and costly and accounts for significant burden of disease. A large number of jurisdictions worldwide have implemented population-level dietary sodium reduction initiatives. No systematic review has examined the impact of these initiatives. OBJECTIVES: • To assess the impact of population-level interventions for dietary sodium reduction in government jurisdictions worldwide.• To assess the differential impact of those initiatives by social and economic indicators. SEARCH METHODS: We searched the following electronic databases from their start date to 5 January 2015: the Cochrane Central Register of Controlled Trials (CENTRAL); Cochrane Public Health Group Specialised Register; MEDLINE; MEDLINE In Process & Other Non-Indexed Citations; EMBASE; Effective Public Health Practice Project Database; Web of Science; Trials Register of Promoting Health Interventions (TRoPHI) databases; and Latin American Caribbean Health Sciences Literature (LILACS). We also searched grey literature, other national sources and references of included studies.This review was conducted in parallel with a comprehensive review of national sodium reduction efforts under way worldwide (Trieu 2015), through which we gained additional information directly from country contacts.We imposed no restrictions on language or publication status. SELECTION CRITERIA: We included population-level initiatives (i.e. interventions that target whole populations, in this case, government jurisdictions, worldwide) for dietary sodium reduction, with at least one pre-intervention data point and at least one post-intervention data point of comparable jurisdiction. We included populations of all ages and the following types of study designs: cluster-randomised, controlled pre-post, interrupted time series and uncontrolled pre-post. We contacted study authors at different points in the review to ask for missing information. DATA COLLECTION AND ANALYSIS: Two review authors extracted data, and two review authors assessed risk of bias for each included initiative.We analysed the impact of initiatives by using estimates of sodium consumption from dietary surveys or urine samples. All estimates were converted to a common metric: salt intake in grams per day. We analysed impact by computing the mean change in salt intake (grams per day) from pre-intervention to post-intervention. MAIN RESULTS: We reviewed a total of 881 full-text documents. From these, we identified 15 national initiatives, including more than 260,000 people, that met the inclusion criteria. None of the initiatives were provided in lower-middle-income or low-income countries. All initiatives except one used an uncontrolled pre-post study design.Because of high levels of study heterogeneity (I2 > 90%), we focused on individual initiatives rather than on pooled results.Ten initiatives provided sufficient data for quantitative analysis of impact (64,798 participants). As required by the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) method, we graded the evidence as very low due to the risk of bias of the included studies, as well as variation in the direction and size of effect across the studies. Five of these showed mean decreases in average daily salt intake per person from pre-intervention to post-intervention, ranging from 1.15 grams/day less (Finland) to 0.35 grams/day less (Ireland). Two initiatives showed mean increase in salt intake from pre-intervention to post-intervention: Canada (1.66) and Switzerland (0.80 grams/day more per person. The remaining initiatives did not show a statistically significant mean change.Seven of the 10 initiatives were multi-component and incorporated intervention activities of a structural nature (e.g. food product reformulation, food procurement policy in specific settings). Of those seven initiatives, four showed a statistically significant mean decrease in salt intake from pre-intervention to post-intervention, ranging from Finland to Ireland (see above), and one showed a statistically significant mean increase in salt intake from pre-intervention to post-intervention (Switzerland; see above).Nine initiatives permitted quantitative analysis of differential impact by sex (men and women separately). For women, three initiatives (China, Finland, France) showed a statistically significant mean decrease, four (Austria, Netherlands, Switzerland, United Kingdom) showed no significant change and two (Canada, United States) showed a statistically significant mean increase in salt intake from pre-intervention to post-intervention. For men, five initiatives (Austria, China, Finland, France, United Kingdom) showed a statistically significant mean decrease, three (Netherlands, Switzerland, United States) showed no significant change and one (Canada) showed a statistically significant mean increase in salt intake from pre-intervention to post-intervention.Information was insufficient to indicate whether a differential change in mean salt intake occurred from pre-intervention to post-intervention by other axes of equity included in the PROGRESS framework (e.g. education, place of residence).We identified no adverse effects of these initiatives.The number of initiatives was insufficient to permit other subgroup analyses, including stratification by intervention type, economic status of country and duration (or start year) of the initiative.Many studies had methodological strengths, including large, nationally representative samples of the population and rigorous measurement of dietary sodium intake. However, all studies were scored as having high risk of bias, reflecting the observational nature of the research and the use of an uncontrolled study design. The quality of evidence for the main outcome was low. We could perform a sensitivity analysis only for impact. AUTHORS' CONCLUSIONS: Population-level interventions in government jurisdictions for dietary sodium reduction have the potential to result in population-wide reductions in salt intake from pre-intervention to post-intervention, particularly if they are multi-component (more than one intervention activity) and incorporate intervention activities of a structural nature (e.g. food product reformulation), and particularly amongst men. Heterogeneity across studies was significant, reflecting different contexts (population and setting) and initiative characteristics. Implementation of future initiatives should embed more effective means of evaluation to help us better understand the variation in the effects.