Active living environments, physical activity and premature cardiometabolic mortality in Canada: a nationwide cohort study.

OBJECTIVE: To evaluate sex-specific and age-specific associations of active living environments (ALEs) with premature cardiometabolic mortality. DESIGN: Population-based retrospective cohort study. SETTING: Residential neighbourhoods (1000-metre circular buffers from the centroids of dissemination areas) across Canada for which the Canadian ALE Measure was derived, based on intersection density, points of interest and dwelling density. PARTICIPANTS: 249 420 survey respondents from an individual-level record linkage between the Canadian Community Health Survey (2000-2010) and the Canadian Mortality Database until 2011, comprised of older women (65-85 years), older men (65-81 years), middle-aged women (45-64 years) and middle-aged men (45-64 years). PRIMARY OUTCOME MEASURES: Premature cardiometabolic mortality and average daily energy expenditure attributable to walking. Multivariable proportional hazards regression models were adjusted for age, educational attainment, dissemination area-level median income, smoking status, obesity, the presence of chronic conditions, season of survey response and survey cycle. RESULTS: Survey respondents contributed a total of 1 451 913 person-years. Greater walking was observed in more favourable ALEs. Walking was associated with lower cardiometabolic death in all groups except for middle-aged men. Favourable ALEs conferred a 22% reduction in death from cardiometabolic causes (HR 0.78, 95% CI 0.63 to 0.97) for older women. CONCLUSIONS: On average, people walk more in favourable ALEs, regardless of sex and age. With the exception of middle-aged men, walking is associated with lower premature cardiometabolic death. Older women living in neighbourhoods that favour active living live longer.

Levels of 1-hydroxypyrene in urine of people living in an oil producing region of the Andean Amazon (Ecuador and Peru).

PURPOSE: Polycyclic aromatic hydrocarbons (PAHs) are contaminants with carcinogenic effects but little is known about their presence in environments surrounding oil drilling operations and spills or exposure levels in nearby communities. The objective of this study was to characterize PAH levels in people living near oil drilling operations in relation to fish consumption, occupation, source of water and other socio-demographic characteristics. METHODS: This pilot study examined PAH exposure by measuring 1-hydroxypyrene (1-OHP) in urine samples using high-performance liquid chromatography and fluorescence detection from 75 women and men in the Ecuadorian and Peruvian Amazon living near oil drilling operations and who answered a questionnaire collecting socio-demographic, occupational and dietary information. Data were analyzed using multiple linear regression models. RESULTS: The mean value of 1-OHP was 0.40 µmol/mol creatinine, 95% CI 0.32-0.46 µmol/mol creatinine. Women who used water from a surface source (for washing clothes or bathing) had almost twice the amount of 1-OHP in their urine (mean 1-OHP = 0.41 µmol/mol creatinine, 95% CI 0.28-0.54 µmol/mol creatinine, n = 23) as women who used water from either a well, a spring or rain (mean 1-OHP = 0.22 µmol/mol creatinine, 95% CI 0.11-0.34 µmol/mol creatinine, n = 6). Men who reported eating a bottom-dwelling species as their most commonly consumed fish (mean 1-OHP = 0.50 µmol/mol creatinine, 95% CI 0.36-0.64 µmol/mol creatinine, n = 31) had twice as much 1-OHP in their urine as men who reported a pelagic fish (mean 1-OHP = 0.25 µmol/mol creatinine, 95% CI 0.15-0.35 µmol/mol creatinine, n = 15), signaling either oral (fish consumption) or dermal (while standing in water fishing benthic species) exposure. CONCLUSIONS: More contact with surface water and benthic fish may result in higher levels of 1-OHP in human urine among the study population. Reducing the amount of oil and wastes entering the waterways in Andean Amazonia would be one way to reduce exposure.

Traffic-related air pollution and prostate cancer risk: a case-control study in Montreal, Canada.

OBJECTIVES: There is a paucity of information on environmental risk factors for prostate cancer. We conducted a case-control study in Montreal to estimate associations with exposure to ground-level nitrogen dioxide (NO2), a marker for traffic-related air pollution. METHODS: Cases were 803 men with incident prostate cancer, ≤75 years of age, and diagnosed across all French hospitals in Montreal. Concurrently, 969 controls were drawn from electoral lists of French-speaking individuals residing in the same electoral districts as the cases and frequency-matched by age. Concentrations of NO2 were measured across Montreal in 2005-2006. We developed a land use regression model to predict concentrations of NO2 across Montreal for 2006. These estimates were back-extrapolated to 1996. Estimates were linked to residential addresses at the time of diagnosis or interview. Unconditional logistic regression was used, adjusting for potential confounding variables. RESULTS: For each increase of 5 parts per billion of NO2, as estimated from the original land use regression model in 2006, the OR5ppb adjusted for personal factors was 1.44 (95% CI 1.21 to 1.73). Adding in contextual factors attenuated the OR5ppb to 1.27 (95% CI 1.03 to 1.58). One method for back-extrapolating concentrations of NO2 to 1996 (about 10 years before the index date) gave the following OR5ppb: 1.41 (95% CI 1.24 to 1.62) when personal factors were included, and 1.30 (95% CI 1.11 to 1.52) when contextual factors were added. CONCLUSIONS: Exposure to ambient concentrations of NO2 at the current address was associated with an increased risk of prostate cancer. This novel finding requires replication.

Mitigating effect of immigration on the relation between income inequality and mortality: a prospective study of 2 million Canadians.

BACKGROUND: The relation between income inequality and mortality in Canada is unclear, and modifying effects of characteristics such as immigration have not been examined. METHODS: Using a cohort of 2 million Canadians followed for mortality from 1991-2001, we calculated HRs and 95% CIs for income inequality of 140 urban areas (Gini coefficient, Atkinson index, coefficient of variation; expressed as continuous variables) and working age (25-64 y) or post-working age (≥65 y) mortality in men and women according to immigration status, accounting for individual and neighbourhood income, and sociodemographic characteristics. Major causes of mortality were examined. RESULTS: Relative to low income inequality, high inequality was associated with greater working age mortality in male (HR(Gini) 1.08, 95% CI 1.04 to 1.13) and female (HR(Gini) 1.12, 95% CI 1.06 to 1.18) non-immigrants for all income inequality indictors. Results were similar for female post-working age mortality. There was no relation between income inequality and mortality in immigrants. Among Canadian-born individuals, associations were greater for alcohol-related mortality (both sexes) and smoking-related causes/transport injuries (women). CONCLUSION: Income inequality is associated with mortality in Canadian-born individuals but not immigrants.

Childhood sleep apnea and neighborhood disadvantage.

OBJECTIVE: To determine whether neighborhood characteristics or socioeconomic status are risk factors for obstructive sleep apnea (OSA) in young children. STUDY DESIGN: In this observational study, we compared residential census tract metrics in Montreal, Canada for 436 children aged 2-8 years who were evaluated for OSA, hypothesizing that the children with proven OSA (OSA group; n = 300) would come from more disadvantaged neighborhoods compared with those children without OSA (no OSA group; n = 136). Children who had undergone previous adenotonsillectomy and those with comorbid disorders were excluded from the analysis. RESULTS: Compared with the no OSA group, the OSA group lived in census tracts with lower median family incomes, higher proportions of children living below the Canadian low-income cutoff (indicating poverty), higher proportions of single-parent families, and greater population densities. The highest probability of having OSA was seen in children referred from the most disadvantaged census tracts and was due primarily to moderate/severe OSA. Group differences remained significant when adjusted for age, race/ethnicity, and obesity. CONCLUSIONS: Compared with the children without OSA, those with OSA were more likely to reside in disadvantaged neighborhoods. Future studies should examine whether these results can be replicated in other settings, especially those with large socioeconomic disparities.

Postmenopausal breast cancer is associated with exposure to traffic-related air pollution in Montreal, Canada: a case-control study.

BACKGROUND: Only about 30% of cases of breast cancer can be explained by accepted risk factors. Occupational studies have shown associations between the incidence of breast cancer and exposure to contaminants that are found in ambient air. OBJECTIVES: We sought to determine whether the incidence of postmenopausal breast cancer is associated with exposure to urban air pollution. METHODS: We used data from a case-control study conducted in Montreal, Quebec, in 1996-1997. Cases were 383 women with incident invasive breast cancer, and controls were 416 women with other incident, malignant cancers, excluding those potentially associated with selected occupational exposures. Concentrations of nitrogen dioxide (NO2) were measured across Montreal in 2005-2006. We developed a land-use regression model to predict concentrations of NO2 across Montreal for 2006, and developed two methods to extrapolate the estimates to 1985 and 1996. We linked these estimates to addresses of residences of subjects at time of interview. We used unconditional logistic regression to adjust for accepted and suspected risk factors and occupational exposures. RESULTS: For each increase of 5 ppb NO2 estimated in 1996, the adjusted odds ratio was 1.31 (95% confidence interval, 1.00-1.71). Although the size of effect varied somewhat across periods, we found an increased risk of approximately 25% for every increase of 5 ppb in exposure. CONCLUSIONS: We found evidence of an association between the incidence of postmenopausal breast cancer and exposure to ambient concentrations of NO2. Further studies are needed to confirm whether NO2 or other components of traffic-related pollution are indeed associated with increased risks.

Deprivation and the development of obesity a multilevel, longitudinal study in England.

BACKGROUND: Evidence indicates that the rising trend in overweight and obesity may be stronger for people from more socioeconomically advantaged backgrounds. PURPOSE: This study used longitudinal, multilevel data to describe trajectories of BMI for people living in more- versus less-deprived neighborhoods. METHODS: Data from 2501 women and 5650 men in the Whitehall II study who were followed for up to 13 years from 1991 to 2004 were analyzed in 2009. BMI was measured on up to three occasions by a trained nurse. The Townsend index of multiple deprivation at census-ward level from the 1991 U.K. census captured neighborhood deprivation. Growth curves summarized change in BMI for men and women according to level of neighborhood deprivation, adjusted for age, individual socioeconomic position (captured by civil service employment grade), smoking status, alcohol intake, and physical activity level. RESULTS: Women who remained in the most-deprived neighborhoods between 1991 and 2004 had higher initial BMI and greater weight gain. Compared to those in the least-deprived neighborhoods, weight gain for a woman of average height in one of the most-deprived neighborhoods was 1.0 kg more over 10 years. Neither BMI nor change in BMI in men was associated with neighborhood deprivation. CONCLUSIONS: Whitehall II provides longitudinal evidence of socioeconomic differences in weight gain among middle-aged women, indicating that the neighborhood environment makes a contribution to the development of overweight and obesity.

BMI and mortality: results from a national longitudinal study of Canadian adults.

Although a clear risk of mortality is associated with obesity, the risk of mortality associated with overweight is equivocal. The objective of this study is to estimate the relationship between BMI and all-cause mortality in a nationally representative sample of Canadian adults. A sample of 11,326 respondents aged >or=25 in the 1994/1995 National Population Health Survey (Canada) was studied using Cox proportional hazards models. A significant increased risk of mortality over the 12 years of follow-up was observed for underweight (BMI <18.5; relative risk (RR) = 1.73, P < 0.001) and obesity class II+ (BMI >35; RR = 1.36, P <0.05). Overweight (BMI 25 to <30) was associated with a significantly decreased risk of death (RR = 0.83, P < 0.05). The RR was close to one for obesity class I (BMI 30-35; RR = 0.95, P >0.05). Our results are similar to those from other recent studies, confirming that underweight and obesity class II+ are clear risk factors for mortality, and showing that when compared to the acceptable BMI category, overweight appears to be protective against mortality. Obesity class I was not associated with an increased risk of mortality.

Social support, material circumstance and health behaviour: influences on health in First Nation and Inuit communities of Canada.

An expansive literature describes the links between social support and health. Though the bulk of this evidence emphasizes the health-enhancing effect of social support, certain aspects can have negative consequences for health (e.g., social obligations). In the Canadian context, the geographically small and socially interconnected nature of First Nation and Inuit communities provides a unique example through which to explore this relationship. Despite reportedly high levels of social support, many First Nation and Inuit communities endure broad social problems, thereby leading us to question the assumption that social support is primarily health protective. We draw from narrative analysis of interviews with 26 First Nation and Inuit Community Health Representatives to critically examine the health and social support relationship, and the social structures through which social support influences health. Findings indicate that there are health-enhancing and health-damaging properties of the health-social support relationship, and that the negative dimensions can significantly outweigh the positive ones. Social support operates at different structural levels, beginning with the individual and extending toward family and community. These social structures are important as they reinforce an individual's sense of belonging, however, these high-density networks can also exert conformity pressures and social obligations that promote health-damaging behaviours such as domestic violence and smoking. The poor material circumstances that characterize so many First Nation and Inuit communities add another layer of complexity as limited resources can trap individuals within the confines of their immediate social contexts. Research and policy interventions must pay close attention to the social context within which social support, health behaviours and material circumstances interact to influence health outcomes among First Nation and Inuit communities.