Table 2.
Characteristics of epidemiological studies investigating sleep disparities in the Canadian population.
| Studies Including Only Children and/or Adolescents < 18 Years Old | ||||||||||
| Study | Study Type | Type of Population | % Women | Mean Age or Age Range (years) |
Sample
Size (n) |
Exposure | Exposure Measurement | Health Outcome | Health Outcome Measurement | Results and Conclusions |
| Brouillette 2011 [26] | Cross-sectional | Children from Montréal | 41 | 2–8 | 436 | Neighbourhood SES | Neighborhood characteristics were evaluated at the census tract level based on the 2006 Canadian census. | Obstructive Sleep Apnea (OSA) | PSG | Compared with the children without OSA, those with OSA were more likely to reside in disadvantaged neighbourhoods |
| Jarrin 2014 [42] | Cross-sectional | Children and adolescents recruited from schools and neighbourhoods in Montreal | 45.6 | 8–17 | 239 | (a) Income (b) Education (c) Social class |
(a) Household income divided into 17 categories (b) Highest parental education divided into 9 categories (c) Subjective Social Status Scale-Youth Version (two 10-rung ladders: school and society, youth reported) |
(a) Sleep quality (b) Daytime sleepiness (c) Sleep disturbances (d) Sleep duration |
(a) youth-rated 10-point scale (b) Pediatric Daytime Sleepiness Scale (c) Children’s Sleep Habits Questionnaire (d) Self-reported sleep duration |
In children, higher subjective SES predicted less daytime sleepiness and longer self-reported sleep duration and higher household income predicted longer parent-reported sleep duration. In adolescents, higher subjective SES was associated with better sleep quality and shorter parent-reported sleep duration, and higher household income was associated with fewer sleep disturbances. |
| Patte 2017 [36] | (a) Cross-sectional (b) Longitudinal cohort followed for 2 years |
Adolescents 9th–12th grade from secondary schools in Ontario and Alberta | 53.9 | 6–14 | (a) 36,088 (b) 7394 |
Income | School area average income (median household income of census divisions that corresponded with school postal codes according to data from the 2011 National Household Survey) |
Sleep duration | (a) Short sleep duration (<8 h) (b) Sleep duration trajectories (short, low-normal, high-normal, long) |
(a) Sufficient sleep was more likely among students attending schools in areas classified in the highest SES group (b) Attending schools in low-income areas predicted short and low-normal sleep duration trajectories over time |
| Costanian 2018 [35] | Cross-sectional | Toddlers from the general population | 49.6 | 1–2 | 3675 | (a) Income (b) Employment status (c) Education |
(a) Household income (<$30,000, $30,000–<$60,000, $60,000–<$100,000, ≥$100,000) (b) Mother’s work status (currently working vs. not currently working) (c) Mother’s education level (college graduate or less vs. more than college graduate) |
Sleep duration | Parent-reported sleep duration (<11 h vs. more) | Toddlers who came from a household with higher annual income were less likely to sleep <11 h per night |
| Chang 2018 [37] | Cross-sectional | Participants from the general population | 48.13 | 3–17 | 4924 | (a) Education (b) Income (c) Employment |
(a) Highest level of education attained in the household for pre-schoolers, children and youth or by the respondent for adults and older adults (less than secondary school degree, secondary school degree, postsecondary school degree) (b) Household income adequacy (based on total annual household income and number of people living in the household and categorized as low, middle, or high) (c) Employment status (full-time, part-time, unemployed) for adults and older adults |
Sleep duration | Self-reported or parent-reported (when participant have less than 12 years) sleep duration (recommended, short, long according to guidelines) | Among pre-schoolers, low household income was significantly associated with short sleep. |
| Laganiere 2019 [38] | Longitudinal cohort followed for 4 years | Children recruited at birth in obstetric clinics of Montreal and Hamilton | 26.56 | 0–4 | 529 | Global SES estimated with (a) education and (b) income | High SES (high maternal education level and high income) vs. middle/low SES (low on at least one of the variables) | Sleep rhythmic movements | Single question + Children ’s Sleep Habits Questionnaire) |
Lower SES predicted sleep rhythmic movements in children |
| Matenchuk 2019 [43] | Cross-sectional | Newborn of a population-based birth cohort in Edmonton | 49.56 | 0.25 | 619 | Education | Maternal education (university degree vs. lower) | Sleep duration | Parent-reported sleep duration | Newborns of mothers without a university degree had significantly reduced sleep duration compared to those of mothers with a university degree |
| Studies Including Participants with All Ages | ||||||||||
| Study | Study Type | Type of Population | % Women | Mean or Range Age (years) |
Sample
Size (n) |
Exposure | Exposure Measurement | Health Outcome | Health Outcome Measurement | Results and Conclusions |
| Sutton 2001 [29] | Cross-sectional | Adults from the general population | NA | ≥15 | 10,702 | (a) Education (b) Income (c) Employment |
(a) Scale items are: some secondary or less, secondary graduation, some post-secondary, post-secondary degree or diploma (b) Income adequacy (lowest, next to lowest, middle, next to highest or highest) (c) working status (not in the work force, usually workdays, regular shift work) |
Insomnia | Single question (yes vs. no) | Low socioeconomic status, reflected by having some secondary education or less, lowest income and not being in the work force, was associated with the presence of insomnia |
| Tjepkema 2005 [30] | Cross-sectional | Adults from the general population | NA | ≥15 | 36,984 | (a) Education (b) Income |
(a) Scale items are: less than secondary graduation, secondary graduation, some postsecondary until postsecondary graduation (b) Household income (lowest, lower-middle, upper-middle, highest) |
Insomnia | Insomnia symptoms frequency (none of the time, a little of the time, or some of the time vs. most of the time or all of the time) | People with less education and lower income were more likely to report insomnia |
| Jarrin 2013 [41] | Cross-sectional | Adults from advertisements in Montreal | 81.4 | 30–65 | 177 | (a) Income (b) Education (c) Employment (d) Subjective SES |
(a) Household income (b) Years of education (c) Employment status (employed vs. unemployed) (d) MacArthur Scale of Subjective Social Status (scale 1–10) |
(a) Sleep quality (b) Sleep latency (c) Sleep duration (d) Weekend oversleep (e) Daytime sleepiness |
(a) Sleep quality (PSQI Global score) (b) Sleep latency (PSQI sleep latency subscale) (c) Weekday sleep duration (d) Difference between weekend and weekday total sleep duration (e) Measured with Epworth Sleepiness Scale (ESS) |
Higher SES was associated with better sleep quality, shorter sleep latency, longer sleep duration, shorter weekend oversleeps and less daytime sleepiness. Subjective SES better predicted sleep duration, weekend oversleep and daytime sleepiness than objective SES. Objective SES better predicted sleep quality and latency than subjective SES. |
| Bassett 2014 [31] | Retrospective cross-sectional | Adults from the 2008 Montreal Neighborhood Networks and Healthy Aging Study | 64.81 | ≥25 | 2643 | (a) Neighborhood disadvantage (b) Social capital (c) SES |
(a) Neighbourhood disadvantage measure was created using six census tract variables: unemployment rates, median household income, the percentage of immigrants, the percentage of single mothers, the percentage of renters, and the percentage of college educated residents (b) Social capital was measured with the network capital, generalized trust and neighborhood volunteering (c) SES score was created using principal components analysis of respondents’ income, education, and employment status |
Restless sleep | Participants responded yes or no to the item “my sleep was restless.” extracted from the Center for Epidemiologic Studies Depression (CES-D) scale | Women were more likely to experience restless sleep than men. Network capital increased the likelihood of restless sleep in men but not women. High generalized trust decreased the odds of restless sleep in women. Neighbourhood disadvantages increased the odds of restless sleep in women but not men. The association among restless sleep, social capital, and neighbourhood environmental factors differed in male and female Montreal adults. |
| Gjevre 2014 [32] | Cross-sectional | Adults from the general population in Saskatchewan | 50.8 | >18 | 7597 | (a) Income (b) Education |
(a) Household income adequacy (4 levels) Money left over at the end of the month (some, just enough, not enough) (b) Items used are: less than high school, completed high school, completed university, completed other postsecondary education |
Excessive Daytime Sleepiness (EDS) |
ESS score >10 | Not enough money left over at the end of the month increased the risk of EDS |
| Baiden 2015 [33] | Cross-sectional | Participants from the general population | 49.36 | >20 | 19,349 | (a) Education (b) Income |
(a) Postsecondary education (no vs. yes) (b) Annual personal income (6 levels) |
Insomnia | Insomnia symptoms (most/all of the time vs. none/a little of/some of the time) | Higher annual income was associated with less sleep disturbances |
| Nagy 2016 [34] | Cross-sectional | Parents with child of brain-to-society study in Montréal | 73.1 | 41.75 | 339 | (a) Parental social capital (b) Income |
Position generator | Child sleep disturbances | Children’s Sleep Habits Questionnaire | Parents with higher social capital tended to have children with fewer total sleep disturbances than did parents with lower social capital |
| Chang 2018 [37] | Cross-sectional | Participants from the general population | 51.45 | 18–79 | 7250 | (a) Education (b) Income (c) Employment |
(a) Highest level of education attained in the household for pre-schoolers, children and youth or by the respondent for adults and older adults (less than secondary school degree, secondary school degree, postsecondary school degree) (b) Household income adequacy (based on total annual household income and number of people living in the household and categorized as low, middle, or high) (c) Employment status (full-time, part-time, unemployed) for adults and older adults |
Sleep duration | Self-reported or parent-reported (when participant have less than 12 years) sleep duration (recommended, short, long according to guidelines) | Among older adults, less than secondary school education and full-time employment were significantly associated with short sleep. Among adults and older adults, less than secondary school education was significantly associated with long sleep. Unemployed older adults were more likely to sleep longer. |
| Garland 2018 [28] | Retrospective cross-sectional | Adults from the general canadian population | 55 | ≥20 | 34,118 in 2002 And 23,089 in 2012 |
Education | Secondary analysis of Data from the Canadian Community Health Survey-Mental Health cycles 2000–2002 and 2011–2012 | Insomnia | The question “How often do you have trouble going to sleep or staying asleep?” | Over a 10-year period, prevalence of insomnia symptoms increased from 15.6% to 17.1% between 2002 and 2012, representing an absolute increase of 1.5%. The likelihood of occurrence of insomnia symptoms was significantly influenced by education |
| Karunanayake 2018 [27] | Longitudinal | Adults from Canadian indigenous populations in Saskatchewan | 52.4 | ≥18 | 317 | (a) Income (b) Housing conditions (c) Employment status (d) Education (e) Marital status |
Secondary analysis of Data from the First Nations Lung Health Project (FNLHP) | Excessive daytime sleepiness (EDS) | Epworth Sleepiness Scale (ESS) | This study showed an association between incidence of subjective EDS and less money left over at end of the month and having a house in need of repairs |
| Yao 2018 [40] | Cross-sectional | Adults from the general population | 56.91 | 45–85 | 19,584 | (a) Education (b) Income (c) Employment |
(a) Education (middle school and under, secondary school, bachelor’s degree and above) (b) Annual personal income (<$20,000, $20,000–$49,000, $50,000–$99,000, ≥$100,000) (c) Employment status (employed vs. retired) |
Possible RBD | Single question (yes vs. no) | Lower education level was a risk factor of possible RBD |
| Vézina-Im 2019 [39] | Cross-sectional | Women from the general population | 100 | 18–44 | 9749 | (a) Education (b) Income |
(a) Items used are: less than high school; high school diploma; some postsecondary studies; postsecondary certificate/diploma or university degree (b) Household income |
(a) Sleep duration (b) Insomnia |
(a) Insufficient sleep duration (<7 h) (b) Insomnia symptoms (none/little of the time vs. some/most/all the time) |
Lower education was associated with more frequent insomnia symptoms |
| Seaton 2020 [44] | Cross-sectional | Male employees from six workplaces in northern British Columbia | 0 | 18–66 | 227 | (a) Education (b) Income |
(a) Items used are: some high school, completed high school, trades certification/college diploma, university degree (b) Items used are: >CAD $100,000, CAD $50,000–CAD $100,000, <CAD $50,000) |
Sleep duration | Self-reported sleep duration | Education and income were not significantly associated with sleep duration |
EDS = excessive daytime sleepiness; ESS = Epworth Sleepiness Scale; NA = Not Available; OSA = Obstructive Sleep Apnea; PSQI = Pittsburgh Sleep Quality Index; REM = rapid eye movement; RBD = REM sleep behaviour disorder; SES = socioeconomic status.