D. Walter Rasugu Omariba

HIV/AIDS knowledge, women's education, epidemic severity and protective sexual behaviour in low-and middle-income countries

A fundamental public health strategy to reduce the risk of HIV/AIDS is to increase levels of awareness and knowledge about the disease. Although knowledge about HIV/AIDS and protective sexual behaviour are linked theoretically, relatively little is known about their empirical relationship. Using Demographic and Health Survey data from 23 low- and middle-income countries, this study used multilevel logistic regression models: to examine cross-national variability in the relationship between HIV/AIDS knowledge and protective behaviour (condom use and restricted sex); to investigate the moderating influences of womens educational attainment on this relationship; and to test the extent to which severity of the HIV/AIDS epidemic accounts for cross-national variability in the association between HIV/AIDS knowledge and protective behaviour. There was an association between increased knowledge of HIV/AIDS and condom use that varied in strength and form cross-nationally. This cross-national variation was accounted for partially by the socioeconomic characteristics of women resident in the study countries and between-country differences in the severity of the HIV epidemic. While education modified the association between HIV/AIDS knowledge and protective behaviour--stronger associations at lower levels of education--epidemic severity exerted a stronger influence on behaviour than any other characteristic. Finally, this study indicates that protective sexual practices are disturbingly low. In eight of 23 countries, overall levels of condom use to prevent STDs and HIV/AIDS were less than 5.0%. Waiting for the spread of HIV/AIDS infection to change sexual practices in low- and middle-income countries will result in dramatic unnecessary suffering.

Associations of Pregnancy Outcomes and PM2.5 in a National Canadian Study

Background Numerous studies have examined associations between air pollution and pregnancy outcomes, but most have been restricted to urban populations living near monitors. Objectives We examined the association between pregnancy outcomes and fine particulate matter in a large national study including urban and rural areas. Methods Analyses were based on approximately 3 million singleton live births in Canada between 1999 and 2008. Exposures to PM2.5 (particles of median aerodynamic diameter ≤ 2.5 μm) were assigned by mapping the mother’s postal code to a monthly surface based on a national land use regression model that incorporated observations from fixed-site monitoring stations and satellite-derived estimates of PM2.5. Generalized estimating equations were used to examine the association between PM2.5 and preterm birth (gestational age < 37 weeks), term low birth weight (< 2,500 g), small for gestational age (SGA; < 10th percentile of birth weight for gestational age), and term birth weight, adjusting for individual covariates and neighborhood socioeconomic status (SES). Results In fully adjusted models, a 10-μg/m3 increase in PM2.5 over the entire pregnancy was associated with SGA (odds ratio = 1.04; 95% CI 1.01, 1.07) and reduced term birth weight (–20.5 g; 95% CI –24.7, –16.4). Associations varied across subgroups based on maternal place of birth and period (1999–2003 vs. 2004–2008). Conclusions This study, based on approximately 3 million births across Canada and employing PM2.5 estimates from a national spatiotemporal model, provides further evidence linking PM2.5 and pregnancy outcomes. Citation Stieb DM, Chen L, Beckerman BS, Jerrett M, Crouse DL, Omariba DW, Peters PA, van Donkelaar A, Martin RV, Burnett RT, Gilbert NL, Tjepkema M, Liu S, Dugandzic RM. 2016. Associations of pregnancy outcomes and PM2.5 in a National Canadian Study. Environ Health Perspect 124:243–249; http://dx.doi.org/10.1289/ehp.1408995

A national study of the association between traffic-related air pollution and adverse pregnancy outcomes in Canada, 1999-2008.

Numerous studies have examined the association of air pollution with preterm birth and birth weight outcomes. Traffic-related air pollution has also increasingly been identified as an important contributor to adverse health effects of air pollution. We employed a national nitrogen dioxide (NO2) exposure model to examine the association between NO2 and pregnancy outcomes in Canada between 1999 and 2008. National models for NO2 (and particulate matter of median aerodynamic diameter <2.5µm (PM2.5) as a covariate) were developed using ground-based monitoring data, estimates from remote-sensing, land use variables and, for NO2, deterministic gradients relative to road traffic sources. Generalized estimating equations were used to examine associations with preterm birth, term low birth weight (LBW), small for gestational age (SGA) and term birth weight, adjusting for covariates including infant sex, gestational age, maternal age and marital status, parity, urban/rural place of residence, maternal place of birth, season, year of birth and neighbourhood socioeconomic status and per cent visible minority. Associations were reduced considerably after adjustment for individual covariates and neighbourhood per cent visible minority, but remained significant for SGA (odds ratio 1.04, 95%CI 1.02-1.06 per 20ppb NO2) and term birth weight (16.2g reduction, 95% CI 13.6-18.8g per 20ppb NO2). Associations with NO2 were of greater magnitude in a sensitivity analysis using monthly monitoring data, and among births to mothers born in Canada, and in neighbourhoods with higher incomes and a lower proportion of visible minorities. In two pollutant models, associations with NO2 were less sensitive to adjustment for PM2.5 than vice versa, and there was consistent evidence of a dose-response relationship for NO2 but not PM2.5. In this study of approximately 2.5 million Canadian births between 1999 and 2008, we found significant associations of NO2 with SGA and term birth weight which remained significant after adjustment for PM2.5, suggesting that traffic may be a particularly important source with respect to the role of air pollution as a risk factor for adverse pregnancy outcomes.

Canadian cancer risk management model: Evaluation of cancer control

OBJECTIVES The aim of this study was to develop a decision support tool to assess the potential benefits and costs of new healthcare interventions. METHODS The Canadian Partnership Against Cancer (CPAC) commissioned the development of a Cancer Risk Management Model (CRMM)--a computer microsimulation model that simulates individual lives one at a time, from birth to death, taking account of Canadian demographic and labor force characteristics, risk factor exposures, and health histories. Information from all the simulated lives is combined to produce aggregate measures of health outcomes for the population or for particular subpopulations. RESULTS The CRMM can project the population health and economic impacts of cancer control programs in Canada and the impacts of major risk factors, cancer prevention, and screening programs and new cancer treatments on population health and costs to the healthcare system. It estimates both the direct costs of medical care, as well as lost earnings and impacts on tax revenues. The lung and colorectal modules are available through the CPAC Web site (www.cancerview.ca/cancerrriskmanagement) to registered users where structured scenarios can be explored for their projected impacts. Advanced users will be able to specify new scenarios or change existing modules by varying input parameters or by accessing open source code. Model development is now being extended to cervical and breast cancers.

Neighbourhood characteristics, individual attributes and self-rated health among older Canadians.

This study drew on three cycles of the Canadian Community Health Survey and the 2001 Census to examine between-neighbourhood variation in positive and negative self-rated health and the relative effect of individual and neighbourhood characteristics on self-rated health among Canadian adults aged > or = 65. Multilevel logistic regression results showed that there was modest, but significant between-neighbourhood variation in self-rated health. Neighbourhood factors including income, education, and percentage of people aged > or = 65, and visible minority accounted for about 50% and 30% of the neighbourhood variation in negative and positive self-rated health, respectively. Relative to neighbourhood-level characteristics, individual characteristics had a stronger effect on self-rated health with involvement in physical activity, alcohol consumption, sense of community belonging, income, and education being the most important. Although the findings suggest that neighbourhood effects on self-rated health are modest and that individual-level factors are relatively more important determinants of health, research concern for contextual influences on health should continue.

Differences between immigrants at various durations of residence and host population in all-cause mortality, Canada 1991–2006

We used data from the 1991–2006 Canadian Census Mortality and Cancer Follow-up Study to compare all-cause mortality for immigrants with that of the Canadian-born population. The study addressed two related questions. First, do immigrants have a mortality advantage over the Canadian-born? Second, if immigrants have a mortality advantage, does it persist as their duration of residence increases? The analysis fitted sex-stratified hazard regression models for the overall sample and for selected countries of birth (UK, China, India, Philippines, and the Caribbean). Predictors were assessed at baseline. Mortality was lower among immigrants than the Canadian-born even after adjusting for a selected group of socio-demographic and socio-economic factors. The mortality differences persisted even after long residence in Canada, but appeared to be dependent on the age of the individual and the country of origin. Interpreted in light of known explanations of immigrant mortality advantage, the results mostly reflect selection effects.

Immigration, ethnicity, and avoidable mortality in Canada, 1991–2006

Objective. Avoidable mortality is a well-recognized, but less studied indicator of the performance of the health system. First, the study seeks to establish whether immigrants overall and selected foreign-born ethnic groups (Western Europeans, South Asians, Chinese, and Filipinos) have an advantage over nonimmigrants in avoidable mortality. Second, it assesses the effect of sociodemographic and socioeconomic factors on any observed differences by duration of residence. Design. Deaths grouped by cause of death and by behavioral risk factors, namely smoking-related and alcohol-related, were derived from the 1991 Canadian Census Cohort: Mortality and Cancer Follow-up. The analysis estimated age-standardized mortality rates (ASMRs), rate ratios, and rate differences and also fitted hazard regression models for the overall Canadian-born population and for selected foreign-born ethnicities by sex. Predictors were assessed at baseline. Results. Compared to the Canadian-born persons, foreign-born men and women had lower ASMRs for overall avoidable mortality and also for selected causes of avoidable mortality. The only exception to this overall trend was for ischemic heart disease among South Asian women. Except for the order of prominence, the three leading causes of death for nonimmigrant and immigrant men and women overall were ischemic heart diseases, smoking-related diseases, and neoplasms. A similar pattern was observed among the ethnic groups, except for circulatory heart diseases replacing ischemic heart diseases and smoking-related diseases among Chinese and Filipino women, respectively. In the hazard regression analysis, the risk of avoidable mortality was lower for immigrants overall and selected ethnicities irrespective of the duration in Canada compared to nonimmigrants. These differences persisted even with adjustment for sociodemographic and socioeconomic factors. Conclusion. Immigrants overall and the selected ethnicities enjoy an advantage over nonimmigrants in avoidable mortality. However, for certain causes of death especially ischemic heart disease mortality among South Asian women, immigrants appeared worse-off than nonimmigrants. The results suggest differential access to and use of health services, differences in protective health-related behavior, and the healthy immigrant effect.

Immigration, Generational Status and Health Literacy in Canada.

Background: Immigrants, a fast-growing population in Canada, score below the national average in health literacy, but the reasons behind the low scores are largely unknown. Also, there is a need to understand the long-term impact of immigration by examining health literacy by generational status. Objective: To examine health literacy differentials in Canada, comparing immigrants and non-immigrants; as well as immigrant sub-groups by their region of origin, recency of arrival and generational status. Methods: A cross-sectional multi-stage representative sample of 22,818 respondents from the Canadian component of the 2003 International Adult Literacy and Skills survey. Data were collected in the home of each respondent. We used descriptive statistics and logistic regression in this study. Results: Fewer immigrants (24%) than non-immigrants (44%) had the requisite health literacy level. After controlling for selected factors, health literacy was still significantly lower for immigrants compared to non-immigrants (OR = 0.51; 95% CI = 0.37 – 0.70). For the immigrant sub-groups and by generations, initial differences that were observed, disappeared after controlling for selected factors. Overall, health literacy was associated with economic, education, and literacy-related factors, but the association with literacy practices at home and at work was stronger for the immigrants than the non-immigrants. Conclusion: Education and literacy practices at home and at work are important determinants of the population’s health literacy; however, education is more likely to be associated with acquisition, while literacy practices are more likely associated with maintenance of health literacy. This adds to our understanding of the factors associated with health literacy, by immigrant and generational status, and shows how different segments of the population in Canada process health information.

Neighbourhood immigrant concentration and hospitalization: A multilevel analysis of cardiovascular-related admissions in Ontario using linked data

ObjectiveTo assess the influence of neighbourhood immigrant concentration on cardiovascular-disease-related hospitalizations in Canada (CVDH), while adjusting for individual-level immigrant status and socio-economic indicators at individual and neighbourhood levels.MethodsData were from the 2006 Canadian Census linked to the hospital Discharge Abstract Data (DAD) for the province of Ontario. Adults (n=1,459,950) aged >-18 years at baseline and grouped by place of birth (Canada, China, South Asia, Europe, and other) were followed between Census Day May 16, 2006 and March 31, 2008. Information on CVDH was obtained from the DAD, while that on immigration and socio-economic indicators was obtained from the Census. The analysis used multilevel logistic regression.ResultsUnadjusted results showed that CVDH was significantly lower among people living in neighbourhoods with medium and high immigrant concentration. Neighbourhood immigrant concentration tended to have no independent effect on CVDH after adjustment for individual-level immigrant status. Immigrants were less likely to experience CVDH irrespective of their country of birth. However, cross-level interaction showed that neighbourhood immigrant concentration provided additional protection to individual-level immigrant status against CVDH for most female immigrant groups, but only for South Asian males.ConclusionThis study resulted from the first-ever linkage of census data to hospitalization data in Canada. It is also the first Canadian study to report on neighbourhood variation and the effect of immigrant concentration on CVDH. The study shows that understanding immigrant health requires both individual and neighbourhood approaches, and a consideration of country of origin.RésuméObjectifÉvaluer l’influence de la concentration d’immigrants au niveau des quartiers sur les hospitalisations liées aux maladies cardiovasculaires (HLMCV) au Canada, tout en tenant compte du statut d’immigrant au niveau individuel et des indicateurs socioéconomiques aux niveaux individuel et du quartier.MéthodeLes données du Recensement du Canada 2006 ont été liées à celles du registre des sorties des hôpitaux (RSH) de la province de l’Ontario. Les adultes (n=1 459 950) de >-1 8 ans au départ, regroupés selon leur lieu de naissance (Canada, Chine, Asie du Sud, Europe et autre), ont été suivis entre le jour du recensement (le 16 mai 2006) et le 31 mars 2008. L’information sur les HLMCV provient du RSH, tandis que celle sur l’immigration et les indicateurs socioéconomiques provient du Recensement. Les données ont été analysées par régression logistique multiniveau.RésultatsLes résultats avant ajustement montrent que les HLMCV étaient significativement plus faibles chez les personnes vivant dans des quartiers à concentrations moyennes et élevées d’immigrants. La concentration d’immigrants dans les quartiers avait tendance à n’avoir aucun effet indépendant sur les HLMCV une fois pris en compte le statut d’immigrant individuel. Les immigrants étaient moins susceptibles de subir des HLMCV, peu importe leur pays de naissance. Toutefois, l’interaction transversale a montré que la concentration d’immigrants dans les quartiers offrait une protection supplémentaire contre les HLMCV à la plupart des groupes de femmes immigrantes, mais chez les hommes, seulement aux immigrants d’Asie du Sud.ConclusionCette étude est le résultat du tout premier maillage entre les données du Recensement et des données sur les hospitalisations au Canada. C’est aussi la première étude canadienne à aborder les écarts par quartier et l’effet de la concentration d’immigrants sur les HLMCV. L’étude montre que pour comprendre la santé des immigrants, il faut allier l’approche individuelle et l’approche par quartier et tenir compte du pays d’origine.