Birth and postnatal outcomes among infants of immigrant parents of different admission categories and parents born in Canada: a population-based retrospective study.

BACKGROUND: Most studies of disparities in birth and postnatal outcomes by parental birthplace combine all immigrants into a single group. We sought to evaluate heterogeneity among immigrants in Canada by comparing birth and postnatal outcomes across different immigration categories. METHODS: We conducted a population-based retrospective study using Statistics Canada data on live births and stillbirths (1993-2017) and infant deaths (1993-2018), linked to parental immigration data (1960-2017). We classified birthing parents as born in Canada, economic-class immigrants, family-class immigrants, or refugees, and evaluated differences in preterm births, small-for-gestational-age (SGA) and large-for-gestational-age (LGA) births, stillbirths, and infant deaths among singleton births by group. RESULTS: Among 7 980 650 births, 1 715 050 (21.5%) were to immigrants, including 632 760 (36.9%) in the economic class, 853 540 (49.8%) in the family class, and 228 740 (13.4%) refugees. Compared with infants of Canadian-born birthing parents, infants of each of the 3 immigrant groups had higher risk of preterm birth, SGA birth, and stillbirth, but lower risk of LGA birth and neonatal death. Compared with infants of economic-class immigrants, infants of refugees had higher risk of early preterm birth (0.9% v. 0.8%, adjusted risk ratio [RR] 1.08, 95% confidence interval [CI] 1.01-1.15) and LGA birth (9.2% v. 7.5%, adjusted RR 1.12, 95% CI 1.10-1.15), but lower risk of SGA birth (10.2% v. 11.0%, adjusted RR 0.92, 95% CI 0.90-0.94), while infants of family-class immigrants had higher risk of SGA birth (12.2% v. 11.0%, adjusted RR 1.01, 95% CI 1.00-1.02). Risk of stillbirth, neonatal death, and overall infant death did not differ significantly among immigrant groups. INTERPRETATION: Heterogeneity exists in outcomes of infants born to immigrants to Canada across immigration categories. These results highlight the importance of disaggregating immigrant populations in studies of health disparities.

Work precarity, employment characteristics and health among Canada's long-term care and seniors' home workers during the COVID-19 pandemic.

Background: The COVID-19 pandemic has highlighted several issues among health care workers in Canada's long-term care and seniors' (LTCS) homes, including labour shortages, staff retention difficulties, overcrowding, and precarious working conditions. There is currently a lack of information on the health, well-being and working conditions of health care workers in LTCS homes - many of them immigrants - and a limited understanding of the relationship between them. This paper examines differences between immigrant and non-immigrant workers' health outcomes and precarious working conditions during the pandemic. Data and methods: The data were from the 2021 Survey on Health Care Workers' Experiences During the Pandemic, which collected information on LTCS home health care workers' (n=2,051) health, employment or work experiences, and working environment during the COVID-19 pandemic. Summary statistics and multivariable logistic regressions were conducted to examine the association between precarious work and workers' health (life stress, mental health and general health), stratified by immigrant status. Selected working characteristics were included in the regression models as covariates, namely occupation, number of locations worked, facility ownership status and number of years worked. Results: Immigrant health care workers were more likely than non-immigrant health care workers to experience precarious work in LTCS homes. Precarious work - characterized by income loss, reduced hours of work, and unpaid leave - was associated with stress and poor general health among immigrant and non-immigrant workers in the sector. Employment precarity was also associated with poor mental health for immigrant workers, but there was no association for non-immigrant workers. Interpretation: Employment precarity and the health and well-being of health care workers warrants further attention, in particular among immigrants employed in the LTCS residential care sector.

The impacts of COVID-19 on immigrants and the healthy immigrant effect: Reflections from Canada.

Discussions about potential long-term health consequences of the COVID-19 pandemic on immigrant health and the healthy immigrant effect (HIE) remain unaddressed. Drawing on Canada as a case study, we summarize the primary and secondary impacts of COVID-19 on immigrants. We find that recent and female immigrants as well refugees have fared far worse than either their more established and male counterparts or the Canadian-born population. We then discuss how COVID-19 might influence (or weaken) immigrants' previously documented health advantage. We highlight two structural conditions induced by the pandemic that may alter the health profile of immigrants; namely, immigration policy and delayed medical treatments. Reflections on the requisite data for monitoring and tracking the overall impact of COVID-19 on immigrants' health are included. Finally, we conclude with a discussion of the Canadian patterns and its potential relevance to immigrants and the HIE in the United States.

Sex differences in COVID-19 deaths in the early months of the pandemic in Canada: An examination with an immigration lens.

Background: At the onset of the COVID-19 pandemic, there was an overrepresentation of males in COVID-19 deaths worldwide, with Canada reporting more female COVID-19 deaths. This paper examines the overrepresentation of female COVID-19 deaths in Canada, with an immigration lens. Data and methods: Data were extracted from the COVID-19 Sex-Disaggregated Data Tracker to compare the sex distribution of COVID-19 deaths in Canada with that of other countries. A linkage of deaths to the Longitudinal Immigration Database (IMDB) allows for the comparison of sex-specific COVID-19 death rates by immigrant status for age and geography, as well as by major employment sector among immigrants, using the tax data from the IMDB. Results: While there were proportionately more female than male COVID-19 deaths in Canada in the early months of the pandemic, this trend was mainly a phenomenon among non-immigrants aged 85 and older. In addition, COVID-19-specific death rates for males were higher than those for females across age groups by immigrant status, except for those aged 85 and older among the non-immigrant population. Among immigrants, the death rate among health care and social assistance workers was higher among males than among females (10.7 vs. 2.9 per 100,000 population). The initially observed overrepresentation of female COVID-19 deaths to male COVID-19 deaths in Canada evened out in the summer of 2021. Interpretation: The higher proportion of female COVID-19 deaths was likely related to the high concentration of COVID-19 deaths in long-term care facilities, where a lower institutionalization rate for immigrants had been observed. Since the implementation of vaccination targeting long-term care facility residents in Canada, the overrepresentation of female COVID-19 deaths ceased.

Hospitalization related to chronic hepatitis B and C in recent immigrants in Canada: An immigration administrative data-linked, population-based cohort study.

Background: Canadian immigrants from countries where the hepatitis B virus (HBV) and hepatitis C virus (HCV) are endemic may be at higher risk of liver-related disease than Canadian-born residents. This study compared HBV- and HCV-related hospitalizations in Canadian immigrants (arriving from 1980 to 2013) and long-term residents (Canadian-born population and pre-1980 immigrants) and aimed to describe the burden of disease in both groups. Methods: Based on the 2004/2005-to-2013/2014 hospital Discharge Abstract Database linked to the 1980-to-2013 Longitudinal Immigration Database, this descriptive cross-sectional study examined the distribution of HBV- and HCV-related hospitalizations, lengths of stay, comorbidities, and sequelae incurred by immigrants and long-term residents in Canada. With a linkage rate of 85%, 5,854,949 immigrants were included in the study. Proportions of HBV- and HCV-related hospitalizations attributable to immigrants were calculated. Results: By birth country risk level, 22% of HBV-related hospital events among recent immigrants, and 20% of those related to HCV, were among people from high-risk countries. Proportionally, fewer immigrants had comorbidities than long-term residents. The top two hospital-related sequelae in both groups were cirrhosis and ascites, and liver cancer. While immigrants made up 16% of the Canadian population, they incurred 37% of HBV-related hospitalizations and 9% of HCV-related hospitalizations, giving ratios of hepatitis-related hospitalizations relative to the population share of 2.3 (95% confidence interval [CI]: 2.2 to 2.5) and 0.5 (95% CI: 0.5 to 0.6) respectively. These ratios were higher among seniors, at 4.4 (95% CI: 3.9 to 4.9) and 2.3 (95% CI: 1.9 to 2.6), respectively. Interpretation: Immigrants can require hospitalization for hepatitis in Canada, especially for HBV. These results may inform health screening for HBV or HCV in the Canadian immigration context.

Access to mental health consultations by immigrants and refugees in Canada.

BACKGROUND: Few quantitative studies have used national-level data to examine access to mental health consultation (MHC) by immigrants in Canada, and even fewer studies investigate MHCs using the following variables: immigrant admission category, duration in Canada since landing and world source regions. This study examines MHCs by immigrants and refugees-compared with those of Canadian-born respondents-while controlling for self-reported mental health (SRMH) and immigrant characteristics, using a population-based survey linked to immigrant landing information. This study, which is based on a linked database, allows for much richer insight into immigrant populations than most previous studies. DATA AND METHODS: Based on data from four cycles (2011 to 2014) of the Canadian Community Health Survey linked to data from the Longitudinal Immigration Database, the odds ratios of having had MHCs are compared between the Canadian-born population and immigrants by immigration dimensions, while controlling for SRMH. Results are hierarchically adjusted for age, sex, socioeconomic factors and sense of belonging. RESULTS: After the above-mentioned factors were controlled for, immigrants were much less likely than Canadian-born respondents to access MHCs. Specifically, compared with the Canadian-born population that had high levels of SRMH, immigrants with high levels of SRMH were statistically less likely to have had an MHC (odds ratio [OR]=0.5, 95% confidence interval [CI] from 0.4 to 0.5), while those with low SRMH levels were more likely to report an MHC (OR=4.8, 95% CI from 4.5 to 5.1, for the Canadian-born population but OR=1.8, 95% CI from 1.5 to 2.1, for immigrants). Most Asian immigrants with low SRMH levels were only as likely to report MHCs as Canadian-born respondents with high SRMH levels. Refugees with low SRMH levels also had only a slightly elevated MHC level (OR=1.6, 95% CI from 1.1 to 2.3) compared with Canadian-born individuals with high SRMH levels. Overall, refugees were not more likely than immigrants of other admission categories to report having had an MHC, even though previous findings have shown that refugees report low levels of SRMH. DISCUSSION: This study provides new evidence on the differences in access to MHC between Canadian-born individuals and immigrants by various characteristics, while controlling for SRMH. Results probably reflect the structural or cultural barriers to MHC and point to a possible pathway to either maintain or improve mental health among immigrants.

All-cause acute care hospitalization rates of immigrants and the Canadian-born population: A linkage study.

BACKGROUND: As Canadian immigration levels increase, knowledge concerning immigrant health becomes increasingly important for health system policy and planning. This study compares the rate of all-cause hospitalization among immigrants with that of their Canadian-born counterparts. DATA AND METHODS: Using records from the Discharge Abstract Database (2004/2005 to 2016/2017) and the Ontario Mental Health Reporting System (2006/2007 to 2017/2018) linked to the 2016 Longitudinal Immigration Database, this study compared the age-standardized hospitalization rates (ASHRs) among immigrants with those of the Canadian-born population; the latter were obtained from a linkage based on the 2011 National Household Survey. Comparisons were made at the International Classification of Diseases chapter level by immigrant landing year, admission category and world region of birth. Quebec data were not available. RESULTS: Overall, ASHRs among immigrants were lower than for the Canadian-born population. Immigrants in the economic class had the lowest ASHR, followed by those in the family class and among refugees. After pregnancy was excluded, leading hospitalization causes were similar for immigrants and the Canadian-born population, where top causes included digestive system and circulatory diseases, injuries, and cancer. In male and female immigrants, the ASHRs were lowest among those from East Asia. By landing year, males arriving earlier had the highest ASHR compared with the most recent arrivals. When pregnancy was excluded and while the differential in ASHRs among females by landing year remained, the magnitude was smaller. INTERPRETATION: These results corroborate those from previous studies suggesting a healthy immigrant effect, but also reveal heterogeneity in ASHRs within the immigrant population. They provide a baseline for comparison of health status between populations, which enables further monitoring and informs health-system policy and planning.

The mental health of immigrants and refugees: Canadian evidence from a nationally linked database.

BACKGROUND: Few studies of the healthy immigrant effect (HIE) have examined the mental health outcomes of Canadian-born individuals on a national scale compared with immigrants by admission category. This study fills this gap by examining the self-reported mental health (SRMH) of immigrants by admission category and other immigration dimensions (e.g., source world region and duration since landing) and making comparisons with Canadian-born respondents to a population-based survey. DATA AND METHODS: Based on four cycles (2011 to 2014) of the Canadian Community Health Survey (CCHS) linked to the Longitudinal Immigration Database (IMDB), odds ratios of high (i.e., excellent or very good) SRMH among Canadian-born respondents and IMDB-linked immigrants are compared using logistic regression. Among the IMDB immigrant population, high SRMH was also examined according to the above-mentioned immigration dimensions. Adjusted results were hierarchically controlled for age, sex, social and economic factors, and sense of belonging. RESULTS: Age-sex adjusted results show that immigrants, especially refugees, are less likely than the Canadian-born population to report high mental health levels, but these differences disappeared after full adjustment. The odds of immigrants having high SRMH differed more by source world region and duration since landing. For example, fully adjusted results show support for the HIE, with recent immigrants (interviewed within 10 years of landing) more likely to report high SRMH than either the Canadian-born population or established immigrants. Greater odds of high SRMH among recent immigrants also holds across admission classes and for selected world regions. DISCUSSION: This study provides new evidence on differences in mental health between Canadian-born individuals and immigrants by various characteristics. Results support a deterioration of the HIE in SRMH and identify factors significantly associated with SRMH. This study can also serve as a baseline for further studies on the impact of COVID-19 on immigrants' mental health by immigrant category.

Impact of health care reform on enrolment of immigrants in primary care in Ontario, Canada.

OBJECTIVES: In 2003, Ontario introduced a patient enrolment system as part of health care reforms, aimed at enhancing primary health care services, but it is unclear whether immigrants have benefited from this health care reform. Therefore, we studied whether this reform changed the extent of immigrants' enrolment in primary care services in Ontario between 2003 and 2012. METHODS: This is a population-based retrospective cohort study, in which a closed cohort of 9231840 Ontario residents between 1985 and 2003 was created, using linked health administrative and immigration databases. Levels of enrolment for traditional and more comprehensive capitation-based practice between 2003 and 2012 were compared by immigrant status. Logistic regression modelling was used to assess the odds of enrolment on primary care practices. RESULTS: Overall enrolment in primary care practices increased gradually after 2004, until 2012, when two-thirds of the cohort (67%) were enrolled. The immigrants' enrolment level remained consistently lower than that of long-term residents over the study period. By 2012, enrolment of immigrants in capitation-based models was significantly lower (17.3% versus 25.4%). In particular, enrolment in Family Health Teams, considered the most comprehensive care model, was considerably lower in immigrants compared with long-term residents (5.6% versus 18.0%; OR = 0.40, 95% CI: 0.40 to 0.41). CONCLUSIONS: Immigrant enrolment rates in new comprehensive primary care models were consistently lower than among long-term residents. This has implication on equitable primary care access for immigrant populations.

Dynamic response of pedestrian thermal comfort under outdoor transient conditions.

Outdoor thermal comfort studies have proved that urban design has a great influence on pedestrians' thermal comfort and that its assessment helps one to understand the quality and usage of the pedestrian environment. However, the majority of outdoor thermal comfort studies perceive pedestrian thermal comfort as "static". The dynamic multiple uses of urban spaces and the highly inhomogeneous urban morphology in high-density cities of the tropics are seldom considered, which leads to a lack of understanding about how pedestrians respond to the changes of the outdoor environment. This study contributes to the understanding of the dynamic thermal comfort using a longitudinal survey that was conducted to obtain information about how thermal sensation changes throughout the walking route and how it is affected by micro-meteorological conditions and the urban geometry. The large variations in micro-meteorological conditions throughout the walking routes are predominantly influenced by the urban geometry. Additionally, the spatial pattern of thermal sensation varies based on the weather conditions, emphasizing the need to account for such variations in the assessment of pedestrian thermal comfort. The results also show that thermal sensation was associated with participants' short-term thermal experience (2-3 min) and that the urban geometry plays an important role in the time-lag effect of meteorological variables on thermal sensation. The findings of this study contribute to improving urban geometry design in order to mitigate the thermal discomfort and create a better pedestrian environment in high-density cities.

Healthy immigrant effect by immigrant category in Canada.

BACKGROUND: Medical screening plays a role in explaining the healthy immigrant effect (HIE) among immigrants newly landed in Canada. The 2002 Immigration and Refugee Protection Act (IRPA) modernized immigration selection by exempting certain immigrant categories (e.g., refugees and certain family-class immigrants) from inadmissibility on health grounds. This study examines the HIE in the IRPA era by sex, with a focus on those categories affected by the IRPA. DATA AND METHODS: The linked Canadian Community Health Survey (CCHS)-Longitudinal Immigration Database (IMDB) was used to compare sex-specific age-standardized proportions of four health measures between Canadian-born and immigrants aged 20 to 65, overall and by duration since landing. Immigrants who landed within three years of the surveys from 2007 to 2014 were examined by sex and immigrant category. Logistic regression was used to further compare the HIE in the same immigrant sub-groups to the Canadian-born, controlling for age and selected confounders. RESULTS: This study found the HIE in most selected measures for immigrants overall, as well as for those recent immigrants arriving under the IRPA, including the family class. Among refugees, the HIE was observed only in less severe chronic conditions; this was especially the case among females. As expected, a strong HIE was observed among economic-class principal applicants. These health advantages persisted even after adjustment for socioeconomic and health factors. For self-rated health, the advantage existed for some groups only after full adjustment. DISCUSSION: This study is a first look at the healthy immigrant effect under the 2002 Immigration and Refugee Protection Act by immigration category. Results corroborate the existing literature on the presence of the HIE among immigrants: the HIE was found to be much weaker among refugees.

Tuberculosis-related hospital use among recent immigrants to Canada.

BACKGROUND: While the incidence of active tuberculosis (TB) in Canada is among the lowest in the world, the rates of TB among immigrants and Indigenous people remain high. In fact, the majority of new active TB cases are disproportionately found among immigrants. This study profiles TB-related acute care hospitalizations among new immigrants to Canada by selected characteristics. DATA AND METHODS: This study is based on the 2000-to-2013 Longitudinal Immigration Database (IMDB) linked to the Canadian Institute for Health Information's Discharge Abstract Database (DAD) from 2001/2002 to 2013/2014. It examines the timing of first TB-related acute care hospitalization occurring from the fiscal year 2001/2002 to the fiscal year 2013/2014 among immigrants who landed in Canada from 2000 to 2013 outside of Quebec and the territories. Mean and median hospital days and the percentage of total TB hospitalizations incurred by these new immigrants are calculated to measure the burden of hospital care among recent immigrants. RESULTS: From 2001/2002 to 2013/2014, 1,120 out of 2.7 million immigrants arriving between 2000 and 2013 were found to have, in total, 1,340 TB-related hospital discharges. The majority of cases (97%) were among immigrants from the Immigration, Refugees and Citizenship Canada (IRCC) designated country list for TB, in which abour three quarters of the cases were from the World Health Organization (WHO) list of high TB-burden countries. Approximately half (45%) of immigrants hospitalized for TB were aged 18 to 34 at the time of hospitalization. Around 10% of all TB patients had been hospitalized before formally landing as immigrants. Mean and median length of hospital stay were 17 days and 11 days, respectively (22 days and 14 days, respectively, for the overall population in Canada). While new immigrants who landed between 2000 and 2013 represent 7% of the overall population of Canada, they incurred 17% of all TB-related hospital discharges occurring during this period. DISCUSSION: This paper demonstrates the value of linked administrative data to understanding immigrant health and is important for future work in this area. Current immigration protocols surrounding TB involve screening for active pulmonary TB and identifying some migrants with latent TB. Results of this study, linking TB-related hospitalizations to immigrant landing files, provide unique information that can inform public health action, as well as migration policy and program development to contribute to the efforts to eliminate TB.

Air ventilation assessment under unstable atmospheric stratification - A comparative study for Hong Kong.

In most current air ventilation assessment (AVA) studies, a simple neutral assumption that does not consider thermal effects is adopted, particularly for numerical simulation practices. With statistics of daytime observations during summer in Hong Kong as an example, this study demonstrates that neutral atmospheric boundary conditions occur with a very low probability, which implies that current practices are indeed far away from reality. This study is devoted to addressing this knowledge gap by cross-comparisons of field measurements, wind tunnel tests, and large-eddy simulations (LES) under neutral and unstable conditions. It is found that LES-computed velocity ratios under unstable conditions are in line with field measurements, while results of simulations under neutral conditions are close to those of wind tunnel tests. Enhanced vertical mixing due to surface heating produces improved ventilation performance in the unstable case. The neutral assumption tends to underestimate pedestrian-level velocity ratios compared to a diabatic condition; hence it is deemed conservative when it is adopted in AVA practices. Moreover, stronger wind direction variance under unstable conditions results in weaker correlation between velocity ratios and frontal area indices than neutral conditions, which implies that street orientations become less important in ventilation under unstable conditions.

Incorporating wind availability into land use regression modelling of air quality in mountainous high-density urban environment.

Urban air quality serves as an important function of the quality of urban life. Land use regression (LUR) modelling of air quality is essential for conducting health impacts assessment but more challenging in mountainous high-density urban scenario due to the complexities of the urban environment. In this study, a total of 21 LUR models are developed for seven kinds of air pollutants (gaseous air pollutants CO, NO2, NOx, O3, SO2 and particulate air pollutants PM2.5, PM10) with reference to three different time periods (summertime, wintertime and annual average of 5-year long-term hourly monitoring data from local air quality monitoring network) in Hong Kong. Under the mountainous high-density urban scenario, we improved the traditional LUR modelling method by incorporating wind availability information into LUR modelling based on surface geomorphometrical analysis. As a result, 269 independent variables were examined to develop the LUR models by using the "ADDRESS" independent variable selection method and stepwise multiple linear regression (MLR). Cross validation has been performed for each resultant model. The results show that wind-related variables are included in most of the resultant models as statistically significant independent variables. Compared with the traditional method, a maximum increase of 20% was achieved in the prediction performance of annual averaged NO2 concentration level by incorporating wind-related variables into LUR model development.

Aerosol pollution and its potential impacts on outdoor human thermal sensation: East Asian perspectives.

Aerosols affect the insolation at ground and thus the Aerosol Optical Depth (AOD, a measure of aerosol pollution) plays an important role on the variation of the Physiological Equivalent Temperature (PET) at locations with different aerosol climatology. The aerosol effects upon PET were studied for the first time at four East Asian cities by coupling a radiative transfer model and a human thermal comfort model which were previously well evaluated. Evident with the MODIS and AERONET AOD observations, the aerosol pollution at Beijing and Seoul was higher than at Chiayi (Taiwan) and Hong Kong. Based on the AERONET data, with background AOD levels the selected temperate cities had similar clear-sky PET values especially during summertime, due to their locations at similar latitudes. This also applied to the sub-tropical cities. Increase in the AOD level to the seasonal average one led to an increase in diffuse solar radiation and in turn an increase in PET for people living in all the cities. However, the heavy aerosol loading environment in Beijing and Seoul in summertime (AODs > 3.0 in episodic situations) reduced the total radiative flux and thus PET values in the cities. On the contrary, relatively lower episodic AOD levels in Chiayi and Hong Kong led to strong diffuse and still strong direct radiative fluxes and resulted in higher PET values, relative to those with seasonal averaged AOD levels. People tended to feel from "hot" to "very hot" during summertime when the AOD reached their average levels from the background level. This implies that in future aerosol effects add further burden to the thermal environment apart from the effects of greenhouse gas-induced global warming. Understanding the interaction between ambient aerosols and outdoor thermal environment is an important first step for effective mitigation measures such as urban greening to reduce the risk of human heat stress. It is also critical to make cities more attractive and enhancing to human well-being to achieve enhancing sustainable urbanization as one of the principal goals for the Nature-based Solutions.

Characterizing prolonged heat effects on mortality in a sub-tropical high-density city, Hong Kong.

Extreme hot weather events are likely to increase under future climate change, and it is exacerbated in urban areas due to the complex urban settings. It causes excess mortality due to prolonged exposure to such extreme heat. However, there is lack of universal definition of prolonged heat or heat wave, which leads to inadequacies of associated risk preparedness. Previous studies focused on estimating temperature-mortality relationship based on temperature thresholds for assessing heat-related health risks but only several studies investigated the association between types of prolonged heat and excess mortality. However, most studies focused on one or a few isolated heat waves, which cannot demonstrate typical scenarios that population has experienced. In addition, there are limited studies on the difference between daytime and nighttime temperature, resulting in insufficiency to conclude the effect of prolonged heat. In sub-tropical high-density cities where prolonged heat is common in summer, it is important to obtain a comprehensive understanding of prolonged heat for a complete assessment of heat-related health risks. In this study, six types of prolonged heat were examined by using a time-stratified analysis. We found that more consecutive hot nights contribute to higher mortality risk while the number of consecutive hot days does not have significant association with excess mortality. For a day after five consecutive hot nights, there were 7.99% [7.64%, 8.35%], 7.74% [6.93%, 8.55%], and 8.14% [7.38%, 8.88%] increases in all-cause, cardiovascular, and respiratory mortality, respectively. Non-consecutive hot days or nights are also found to contribute to short-term mortality risk. For a 7-day-period with at least five non-consecutive hot days and nights, there was 15.61% [14.52%, 16.70%] increase in all-cause mortality at lag 0-1, but only -2.00% [-2.83%, -1.17%] at lag 2-3. Differences in the temperature-mortality relationship caused by hot days and hot nights imply the need to categorize prolonged heat for public health surveillance. Findings also contribute to potential improvement to existing heat-health warning system.

Hospitalization rates among economic immigrants to Canada.

BACKGROUND: Economic immigrants generally, and economic class principal applicants (ECPAs) specifically, tend to have better health than other immigrants. However, health outcomes vary among subcategories within this group, especially by sex. DATA AND METHODS: This study examines hospitalization rates among ECPAs aged 25 to 74 who arrived in Canada between 1980 and 2006 as skilled workers, business immigrants, or live-in caregivers. The analysis used two linked databases to estimate age-standardized hospitalization rates (ASHRs) overall and for leading causes by sex. ASHRs of ECPA subcategories were compared with each other and with those of the Canadian-born population. Logistic regression was used to derive odds ratios for hospitalization among ECPAs, by sex. RESULTS: Male and female ECPAs aged 25 to 74 had significantly lower all-cause ASHRs than did the Canadian-born population in the same age range. This pattern prevailed for each ECPA subcategory and for each disease examined. Compared with skilled workers, business immigrants had lower odds of hospitalization; live-in caregivers who arrived after 1992 had higher odds. Adjustment for education, official language proficiency, and world region reduced the strength of or eliminated these associations. INTERPRETATION: Compared with the Canadian-born population, ECPAs generally had low hospitalization rates. Differences were apparent among ECPA subcategories.

Developing Street-Level PM2.5 and PM10 Land Use Regression Models in High-Density Hong Kong with Urban Morphological Factors.

Monitoring street-level particulates is essential to air quality management but challenging in high-density Hong Kong due to limitations in local monitoring network and the complexities of street environment. By employing vehicle-based mobile measurements, land use regression (LUR) models were developed to estimate the spatial variation of PM2.5 and PM10 in the downtown area of Hong Kong. Sampling runs were conducted along routes measuring a total of 30 km during a selected measurement period of total 14 days. In total, 321 independent variables were examined to develop LUR models by using stepwise regression with PM2.5 and PM10 as dependent variables. Approximately, 10% increases in the model adjusted R(2) were achieved by integrating urban/building morphology as independent variables into the LUR models. Resultant LUR models show that the most decisive factors on street-level air quality in Hong Kong are frontal area index, an urban/building morphological parameter, and road network line density and traffic volume, two parameters of road traffic. The adjusted R(2) of the final LUR models of PM2.5 and PM10 are 0.633 and 0.707, respectively. These results indicate that urban morphology is more decisive to the street-level air quality in high-density cities than other cities. Air pollution hotspots were also identified based on the LUR mapping.

Acute care hospitalization of refugees to Canada: Linked data for immigrants from Poland, Vietnam and the Middle East.

BACKGROUND: Refugees arrive in Canada with settlement challenges different from those faced by other immigrants, including a higher risk of poor health. This study reports hospitalization rates for the three fiscal years from 2006/2007 through 2008/2009 for immigrants who arrived during the 1980-to-2006 period, with a focus on three refugee groups. DATA AND METHODS: Information from two linked databases was used to estimate age-standardized hospitalization rates (ASHRs) per 10,000 population aged 30 or older for all causes (excluding pregnancy) and for leading causes, by immigrant category and by refugee subcategory. The analysis focused on refugees from Poland, Vietnam and the Middle East, whose hospitalization rates were compared with those of the Canadian-born population and/or economic class immigrants from the same areas. RESULTS: Immigrants aged 30 or older, including refugees, had significantly lower all-cause ASHRs than did the Canadian-born population. All-cause ASHRs were 470 per 10,000 for immigrants overall and 494 for refugees, compared with 891 for the Canadian-born. Of the three source areas, immigrants and refugees from Vietnam had lower ASHRs. The circulatory disease-specific ASHR for government-assisted refugees from the Middle East was similar to that of the Canadian-born population (142 and 158, respectively). Except for those from Poland, refugees typically had higher ASHRs than did their economic class counterparts. INTERPRETATION: Refugees, like other immigrants, generally had lower hospitalization rates than did the Canadian-born population, but some subgroups were particularly susceptible to hospitalization for specific chronic diseases.

Acute care hospitalization, by immigrant category: Linking hospital data and the Immigrant Landing File in Canada.

BACKGROUND: Although immigrants tend to be healthier than the Canadian-born population when they arrive, subgroups, notably different immigration categories, may differ in health and health care use. Data limitations have meant the research has seldom focused on category of immigrant-economic, family or refugee. A newly linked database has made it possible to study acute care hospitalization by immigration category and source region. DATA AND METHODS: The Immigrant Landing File-Hospital Discharge Abstract Linked Database (n = 2.6 million) was used to derive sex-specific crude and age-standardized hospitalization rates (ASHRs) per 10,000 population for all-cause and leading causes of hospitalization during the 2006/2007-to-2008/2009 period. RESULTS: Economic class immigrants had lower all-cause ASHRs than did their family class or refugee counterparts. Male refugees had high ASHRs overall and for circulatory diseases, digestive diseases, injury, and cancer. Female differences by immigrant class were less pronounced. All-cause ASHRs (excluding pregnancy) rose with years since arrival in Canada for male and female immigrants. Immigrants from East Asia had the lowest ASHRs; those from the United States, the highest. INTERPRETATION: Although hospital use is an imperfect indicator of health status, this study supports an initial healthy immigrant effect and its subsequent decline. Marked differences emerged among immigrant subgroups with some, notably refugees and immigrants from the United States, having significantly higher hospitalization rates overall and for leading causes, compared with other groups.