Chronic disease prevalence and preventive care among Ontario social housing residents compared with the general population: a population-based cohort study
Chronic disease prevalence and preventive care among Ontario social housing residents compared with the general population: a population-based cohort study
Older adults living in social housing report poor health and access to healthcare services. This study aimed to estimate the prevalence of chronic diseases, influenza vaccination and cancer screenings among social housing residents versus non-residents in Ontario, Canada.
We conducted a population-based cohort study for all health-insured Ontarians alive and aged 40 or older as of 1 January 2020. Social housing residents were identified using postal codes. Validated health administrative data case definitions were used to identify individuals with diabetes, hypertension, chronic obstructive pulmonary disease, asthma, congestive heart failure and cardiovascular disease. Influenza vaccination and mammography, Pap and colorectal cancer screenings were identified among screen-eligible residents using health administrative data.
The prevalence of all chronic diseases was higher among social housing residents across all age groups: 40–59, 60–79 and 80+ years. Influenza vaccination rates in 2018–2019 were lower among social housing residents aged 60–79 and 80+ years. Mammography rates for women aged 50–69 years in 2018–2019 were 10–11% lower among social housing residents across all age groups compared with non-residents. Pap screening rates for women aged 40–69 in 2018–2019 were 6–8% lower among social housing residents. The percentage of colorectal screening in both women and men aged 52–74 was lower (9–10% in men and 6–7% in women) in social housing compared with the general population in 2019–2020.
There is a higher prevalence of chronic diseases and lower cancer screening rates among the growing population of older adults in social housing in Ontario, Canada.
Data are available upon reasonable request. The dataset from this study is held securely in coded form at ICES. While legal data sharing agreements between ICES and data providers (eg, healthcare organisations and government) prohibit ICES from making the dataset publicly available, access may be granted to those who meet prespecified criteria for confidential access, available at www.ices.on.ca/DAS (email: [email protected]). The full dataset creation plan and underlying analytical code are available from the authors upon request, understanding that the computer programmes may rely upon coding templates or macros that are unique to ICES and are therefore either inaccessible or may require modification.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
WHAT THIS STUDY ADDS
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
Social housing programmes, a subset of affordable rental housing, provide financially supported accommodation for low-income older adults and families.1 These programmes, sometimes referred to as subsidised or public housing, offer rents geared-to-income or supplemented by subsidies.1 In Ontario, Canada, approximately 75 000 older adults lived in social housing in 2015.2 Additionally, 50 295 older adult households were on waitlists for social housing, representing one-third of all households on such waitlists in Ontario.2
Literature shows us that social housing residents tend to experience higher levels of poverty, unemployment and lower education attainment compared with the general population.2 3 Additionally, studies have highlighted that adults aged 40 and older living in social housing self-report poorer health and experience a higher burden of chronic diseases, such as cardiovascular disease (CVD) and diabetes, compared with older adults not residing in social housing.4 Chronic diseases are a critical public health issue for healthcare providers and policymakers, as they are associated with numerous negative health outcomes, reduced health-related quality of life and increased healthcare utilisation and costs.5 The social housing system in Ontario is as large as the province’s long-term care system, emphasising the increasing need for access to home care and support services among older adults residing in social housing to maintain their health and independence.2 6 Moreover, social housing residents may face disparities in healthcare access, such as challenges in accessing free and publicly provided and funded screening and vaccinations, due to limited resources and facilities compared with residents of long-term care homes.7 Current guidelines recommend regular breast cancer screening for individuals aged 50–74, cervical cancer screening for women aged 21–69, colorectal cancer screening for those aged 50–74 and annual influenza vaccination for all age groups.8–10
Despite the importance of understanding the health status and preventive care practices of Ontario social housing residents, limited research exists on these topics. This study aims to describe the prevalence of chronic diseases among Ontario social housing residents aged 40 years and older compared with non-residents of the same age and sex. This study will also investigate rates of cancer screening and influenza vaccination as indicators of preventive care service utilisation.
We conducted a population-based cohort study of administrative health data from Ontario, the most populous province in Canada. Data were obtained from the health service records of Ontarians securely held in linked, coded form and analysed at the not-for-profit research institute, ICES (www.ices.on.ca). The data held by ICES has undergone rigorous processing to assure accuracy and reliability and is considered the gold standard in terms of administrative health databases in Ontario, Canada. The data sets used in this study were physician service claims captured in the publicly-funded Ontario Health Insurance Plan (OHIP Claims History Database); hospital discharge abstracts captured in the Canadian Institute for Health Information (CIHI) Discharge Abstract Database (DAD); emergency department records captured in the CIHI National Ambulatory Care Reporting System (NACRS); same day surgeries from the Same Day Surgery Database (SDS); mammography screening records captured in the Ontario Breast Screening Program (OBSP) data set; cancer history captured in the Ontario Cancer Registry (OCR); eligible recipients of primary care services in the Primary Care Population (PCPOP) data set; and demographic, place of residence and vital status information from the OHIP Registered Persons Database (RPDB). These databases are linked by ICES at the individual level and analysed in anonymous, coded form under section 45 of Ontario’s Personal Health Information Protection Act.
We studied two cohorts of adults, aged 40 and older, who were alive on 1 January 2020. One cohort consisted of individuals residing in Ontario social housing buildings (provided either through the municipal government or not-for-profit organisations), identified by their unique postal codes, while the other cohort included those not residing in social housing.11 The social housing unique postal codes were obtained from publicly available lists provided by each Ontario municipality, which we rigorously compiled and verified as being unique to social housing buildings using a national postal code ‘lookup’ database.12 A community-based intervention found high rates of chronic disease among social housing residents aged 55 and older.11 To capture the potential early onset of cardiometabolic diseases in this population, we established cohorts starting from age 40 and older. The age of 40 years was chosen because many chronic diseases become prevalent after this decade and chronic disease screening guidelines recommend screening initiation commencing at 40 years of age or even earlier for certain conditions, such as diabetes.13–15 Social housing street addresses were collected from the websites of the 47 Ontario regional social housing authorities or directly from their representatives. The respective postal codes were obtained from Canada Post. We visually validated whether social housing buildings shared postal codes with adjacent residential or commercial buildings using Google Maps and Canada Post. The study was restricted to the 2776 postal codes where at least 50% of the housing units within that postal code were designated as social housing. This method has been used in similar studies.7 16
Chronic diseases: we identified people with a history of congestive heart failure (CHF), diabetes, hypertension, asthma and chronic obstructive pulmonary disease (COPD) if they had ever been present in the respective ICES-derived cohorts populated using validated algorithms. Detailed descriptions of these algorithms are described elsewhere.17–20 For CVD, we used a 5-year lookback of ICD-10 (International Classification of Diseases 10th Revision) codes in DAD, NACRS and SDS for hospital visits attributed to acute myocardial infarction, stroke, coronary heart disease or peripheral vascular disease, or hospital visits with intervention codes for percutaneous coronary intervention, coronary artery bypass graft or carotid endarterectomy.
Influenza vaccination: the individual was categorised as having at least one influenza vaccination if they had any OHIP billing code for influenza vaccination between 1 January 2018 and 31 December 2019.
Pap screening: individuals were considered eligible for Pap screening if they were female and aged 40–69 years as of 1 January 2020, according to the RPDB and did not have a history of cervical cancer or a hysterectomy based on OHIP billing codes and OCR entries. Pap screening was determined from specific billing codes in OHIP from 1 January 2018 to 31 December 2019.
Mammography screening: individuals were considered eligible for mammography screening if they were female and aged 50–69 years as of 1 January 2020, in RPDB and did not have a history of breast cancer and/or mastectomy according to OHIP billing records and OCR entries. All full and partial view mammography between 1 January 2018 and 31 December 2019, conducted as part of the OBSP and conducted outside of that programme were included.
Colorectal cancer screening: individuals eligible for colorectal cancer screening were defined as those aged 52–74 years, excluding high-risk individuals with a history of colorectal cancer or inflammatory bowel diseases.21 Being up to date for colorectal screening from 1 April 2019 to 1 April 2020 was determined by the PCPOP database and defined as having at least one faecal immunochemical test/faecal occult blood test in the previous 2 years or flexible sigmoidoscopy or colonoscopy in the past 10 years.
The characteristics of the cohorts were summarised using descriptive statistics. The primary outcomes of interest were the prevalence of the six specified chronic diseases as well as the rates of influenza vaccination, mammography, Pap screening and colorectal cancer screening. We calculated 95% confidence intervals (CIs) for estimates of the difference between social housing residents and non-residents by age and sex using a chi-square (χ2) distribution. We calculated crude prevalence rates by dividing the number of people with chronic diseases by the total population. All statistical analyses were performed using SPSS version 28.1.22
There were 14 568 499 individuals identified in the administrative health data, of which 7 361 110 (50.5%) met the cohort eligibility criteria of being 40 years or older during the accrual period. Of these individuals, 191 375 (2.6%) resided in social housing and formed the social housing cohort, while 7 169 735 (97.4%) were non-residents and formed the complement cohort.
The age distribution differed between the social housing and the complement cohorts (see table 1). Notably, the social housing cohort had a lower percentage of adults aged 40–59 (44.6% of the social housing cohort vs 54.1% of the complement cohort) and a higher percentage of adults aged 80 years and older (13.8% of the social housing cohort vs 7.5% of the complement cohort). This pattern was consistent across sexes.
Table 1
Age and sex distributions of the social housing and complement cohorts
There were large differences in the demographic characteristics and region of residence between the social housing and complement cohorts (see table 2). Compared with the complement cohort, a lower percentage of social housing residents were men (39.2% vs 48.4%) and a higher percentage lived in the Toronto region (39.3% vs 18.4%).
Table 2
Demographics in social housing and complement cohorts
The prevalence of all six chronic diseases (ie, diabetes, hypertension, COPD, asthma, CHF and CVD) was relatively higher among social housing residents across the entire sample, as well as when stratified by age groups and sex (see table 3). Hypertension was the most prevalent chronic disease in both the social housing cohort (50.8%) and complement cohort (39.0%). Several chronic diseases were observed to have nearly twice the prevalence rate in the social housing cohort compared with the complement cohort (eg, 21.5% vs 11.6% for COPD and 6.6% vs 3.3% for CHF). Similarly, among individuals aged 40–59, the prevalence rate of diabetes was nearly twice as high among social housing residents compared with non-residents (19.5% vs 10.7%).
Table 3
Chronic disease prevalence in social housing and complement cohorts by age and sex
Differences between the social housing resident and non-resident cohorts were also observed in the rates of influenza vaccination (see table 4). Compared with non-residents, the social housing cohort was more likely to be immunised in 2018 and 2019. However, this finding was not consistent across all age groups; social housing residents aged 80 and above were less likely to be immunised than the same age group in the complement cohort. Furthermore, the findings varied between sexes: females in social housing were more likely to be immunised than females in the complement cohort, while males in social housing were less likely to be immunised.
Table 4
Influenza vaccination in social housing and complement cohorts, 2018–2019
The rates of mammography, Pap screening and colorectal cancer screening varied between the social housing and complement cohorts (see table 5). The number of individuals eligible for screening (denominators for the rates) can be found in online supplemental file table S1. Among women, the percentage of social housing residents who underwent mammography in 2018–2019 was lower across all age groups compared with the complement cohort (all ages: 46.9% vs 57.0%; 50–59 years: 43.4% vs 53.3%; 60–69 years: 50.6% vs 61.2%). Similarly, the percentage of women who received Pap screening in 2018–2019 was relatively lower across all age groups (all ages: 33.5% vs 40.8%; 40–59 years: 36.1% vs 42.6%; 60–69 years: 28.4% vs 36.8%). Additionally, the percentage of residents up to date with colorectal screening in both women and men was significantly lower in social housing compared with the general population in 2019–2020 (62.6% vs 69.9%).
Table 5
Cancer screening (mammography, Pap and colorectal) in social housing and complement cohorts from 2018 to 2020
We sought to assess the prevalence of chronic disease and preventive care among individuals aged 40 and older residing in social housing compared with a similar population not living in social housing in Ontario, Canada. The study revealed that the overall prevalence of chronic diseases is higher among those in social housing across all age groups for both men and women, compared with age-matched populations in published papers.5 23–26 This included diabetes (18% vs 30%), hypertension (39% vs 51%), COPD (11.6% vs 21.5%), asthma (12.7% vs 18.6%), CHF (3.3% vs 6.6%) and CVD (2.7% vs 4.4%). Preventive rates of vaccinations were higher in the social housing population (11.0% vs 9.5%), while Pap screening (21.7% vs 31.0%), mammography (20.6% vs 28.3%) and colorectal cancer screening (62.6% vs 69.9%) rates were lower. This study fills a significant gap in the literature, as few published studies explore the burden of chronic diseases and none examine the rates of preventative measures such as vaccination and cancer screening among individuals aged 40 and older living in social housing in Canada.
The proportion of Canadians living with chronic diseases and multimorbidity is expected to rise alongside the ageing population.23 These health concerns may be particularly pronounced in individuals residing in social housing which has a large older adult population. A study found that approximately 13% of Canadian adults had two or more chronic diseases.23 Consistent with our findings, this study indicated that individuals with three or more chronic diseases were more likely to be female, older, belong to lower income groups and have lower educational attainment.23 Another study focusing on type 2 diabetes risk among older adults in social housing in Canada found that 96.7% of low-income older adults living in social housing were at moderate to high risk of developing diabetes.27 Our findings, based on administrative health data, are consistent with previous Canadian studies using self-reported surveys, showing a higher prevalence of chronic diseases among social housing residents in Ontario.
A recent population-based cohort study in 2021 evaluated trends in the prevalence of chronic disease in Ontario.28 The study revealed an 11% increase in patients with at least one chronic disease over the 10-year period, with a 12.2% increase in multimorbidity, driven primarily by population.28 Similarly, our study demonstrated a higher prevalence of chronic diseases among older age groups, particularly pronounced among individuals in social housing, who have higher levels of unmet needs. These findings and previous studies conclude that these shifts towards more severe conditions underscore the necessity for effective population health management and increased healthcare spending on programmes tailored to the needs of an ageing population.5
Influenza vaccination rates were slightly higher in the social housing population. The higher vaccination rates among adults in social housing may be attributed to targeted public health programmes or pharmacy initiatives during flu shot campaigns.29 30 Each year, seasonal influenza accounts for an estimated 290 000–650 000 deaths globally, primarily among older adults.31–33 Our finding of generally higher immunisation rates among social housing residents is encouraging and sends an important message to government and public health officials, despite overall coverage rates remaining below 20%. It should be noted that since 2018, a growing proportion of influenza vaccinations among seniors in Ontario has been administered by pharmacists, potentially increasing true population coverage rates. Recent literature indicates that this additional pharmacist coverage in 2018 and 2019 ranged from 5% to 20% depending on age.34 However, our comparison focuses on physician-administered vaccination rates across both cohorts and does not include pharmacist influenza vaccination rates, which remains appropriate. Additionally, older adults tend to have higher vaccination rates because they are often targeted by public health campaigns that emphasise their higher risk of severe complications from illnesses like influenza. Therefore, they may be more aware of the need for influenza vaccines. Younger adults and children, especially those under 18, may not perceive themselves as being at high risk for complications from the influenza, leading to lower vaccination rates.
There is a lack of studies reporting on cancer screening rates among social housing residents in Canada, which limits comparisons to previous reports. These findings highlight the need to optimise cancer screening strategies in this population. Cancer remains one of the leading causes of death in Canada, with breast cancer accounting for one of the highest mortality rates.35–37 It is estimated that 1 out of 9 Canadian women will be diagnosed with breast cancer during their lifetime and 1 in 29 will die of it.35 Mammography plays a vital role in breast cancer screening strategies.37 Since the initiation of population-based mammography for screening, there has been a significant reduction in breast cancer mortality.38 Although the utilisation of mammography for screening has increased gradually over the past two decades, it has been reported to be suboptimal, particularly among certain groups of women.35 39 Socioeconomic, cultural, linguistic, structural and systemic barriers have been reported as contributing factors to observed disparities.35 39 Those in higher income groups are more likely to be tested, diagnosed and treated at earlier stages than those in lower income groups.40 In our study, women who lived in social housing had an 8% lower mammography rate, and socioeconomic and systemic barriers reported in the literature may contribute to this disparity.3 39
Data from the 2016 Canadian Community Health Survey showed that 25% of participants did not have a timely Pap screening.41 Lower income has been associated with not having timely recommended screening tests.41 While data on Pap cervical cancer screening rates among women in the social housing are scarce, disparities in cervical cancer screening among some vulnerable groups are well documented. For example, women born in Muslim-majority countries living in Ontario, Canada are less likely to be up to date on cervical screening; more than 47% of immigrant women studied in Ontario were overdue for their Pap screening.42 However, the 10% disparity in Pap test screening observed among women in social housing cohort compared with the complement cohort in our study underscores the substantial progress still needed to achieve equity in knowledge and healthcare access. Despite cancer being a leading cause of death in Canada, and screening and prevention efforts reducing cancer morbidity and mortality, our findings emphasise the necessity for targeted cancer screening interventions among social housing residents. We believe that barriers to healthcare access exist at various levels, including both patient-level and systemic barriers to screening, which are more prevalent among vulnerable populations, including those of lower socioeconomic status. These barriers can significantly impact quality of life and life expectancy. Improved targeted programmes for cancer screening among women in social housing are needed.
For all Ontario patients who had family doctors from January 2009 to December 2010, 85% had undergone colorectal cancer screening according to the same parameters defined in our paper.43 This proportion is higher than what we observed, as the entire sample in that study was rostered to a family physician, unlike the low-income social housing population. Another study using ICES administrative data for 2019 and 2020 reported average colorectal cancer screening rates, using the same definition parameters, of 67% for women and 63% for men.44 When stratified by income quintiles, they found screening rates of 59% in the lowest quintile and 70% in the highest quintile.44 While our data is sex-stratified, it aligns with these findings, reinforcing the message that the social housing population does not receive colorectal cancer screening at rates comparable to the general population.
Our study has several major strengths. The use of administrative health data allowed us to examine the chronic disease status and preventative care behaviours within a large sample. This approach also helped mitigate biases associated with self-reported data (eg, recall, social desirability) and self-selection (eg, non-representative participants). However, the study also has important limitations. There were some differences between the two populations that may impact the comparability of results. We were unable to control for geography and income in a reference population. The administrative data also lacks information on social determinants of health and gender. Additionally, while efforts were made to accurately define the social housing cohort, some inaccuracies may arise due to population movement in and out of social housing. Although, this impact is likely minimal, as individuals often relocate between social housing buildings.
Our study demonstrated a higher prevalence of chronic diseases and lower cancer screening rates among adult social housing residents in Ontario, Canada, compared with the general population. These findings are crucial for informing public health and prevention efforts tailored to this growing and vulnerable population. It is possible that specific strategies such as mobile health units and community outreach programmes that bring screening and vaccination services directly to residents, could help reduce access barriers, such as related to transportation, for this population. One such intervention in social housing is the Community Paramedicine at Clinic (CP@clinic) programme which conducts cardiometabolic screening among older adults.45 However, further research is required to determine if this will be effective.
Data are available upon reasonable request. The dataset from this study is held securely in coded form at ICES. While legal data sharing agreements between ICES and data providers (eg, healthcare organisations and government) prohibit ICES from making the dataset publicly available, access may be granted to those who meet prespecified criteria for confidential access, available at www.ices.on.ca/DAS (email: [email protected]). The full dataset creation plan and underlying analytical code are available from the authors upon request, understanding that the computer programmes may rely upon coding templates or macros that are unique to ICES and are therefore either inaccessible or may require modification.
Not applicable.
This study was reviewed by the Hamilton Integrated Research Ethics Board (Project #11476-C) and was granted an exemption as all individual-level study data was held and analysed within ICES under section 45 of Ontario’s Personal Health Information Protection Act.
This study was supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health. This document used data adapted from the Statistics Canada Postal CodeOM Conversion File, which is based on data licensed from Canada Post Corporation, and/or data adapted from the Ontario Ministry of Health Postal Code Conversion File, which contains data copied under license from Canada Post Corporation and Statistics Canada. Parts of this material are based on data and/or information compiled and provided by the Ontario Ministry of Health, Ontario Health and the Canadian Institute for Health Information. The analyses, conclusions, opinions and statements expressed herein are solely those of the authors and do not reflect those of the funding or data sources; no endorsement is intended or should be inferred.
