Baseline data from volunteer participants was collected between 2010 to 2015 and included two cohorts: 1) data collected using self-report questionnaires administered through 60-minute computer-assisted telephone interviews (n = 21,241), and 2) data collected at designated data collection sites or at the participant’s home (n = 30,097). For the purposes of this study, data from the cohorts were grouped as there was no difference in the variables of interest other than how the data was collected (Fig. 1). We included respondents between the ages of 45 and 85 who had data available for our dependent and independent variables. Excluded from the CLSA and thus our research, were residents in the three territories, persons living on federal First Nations reserves, full-time members of the Canadian Armed Forces, individuals living in institutions, and people who were not able to respond in English or French or who had cognitive impairment. Furthermore, individuals were excluded from our analysis if any one of the CM health conditions being assessed was unknown to the participant, if the participant refused to answer the question, or if the participant did not complete any variables included in this study (n = 316).
Variables
Activity Limitation (dependent variable) – Activity limitation was evaluated using the Older American Resources and Services (OARS) scale. This 14-item questionnaire assesses an individual’s functioning with Activities of Daily Living (ADLs – dressing, feeding, appearance management, walking, getting out of bed, bathing, toileting) and Instrumental Activities of Daily Living (iADLs – telephone use, travel, shopping, meal preparation, housework, taking medication, finances). Item responses produce an unadjusted OARS score. For each ADL or iADL task included in the questionnaire, participants had three possible response options (able to complete the task, able to complete the task with assistance, unable to complete the task). One question regarding toileting asked if the participant had difficulty with incontinence and what was the frequency of the incontinence (never or less than once a week, once or twice a week, three times a week or more, don't know/no answer, refused to answer).
To determine the level of activity limitation, participants were first assigned an ADL problem score based on the number of activities a participant identified as being able to complete with assistance (from the unadjusted OARS questionnaire) and the number of activities missing (no response provided by the participant). A participant’s ability to prepare their own meals was then considered in conjunction with the ADL problem score to determine their level of activity limitation, which was categorized as: no functional impairment, mild impairment, moderate impairment, severe impairment, total impairment. For the purposes of our analysis, the severe and total impairment categories were grouped. Table 1 outlines the process by which these variables were considered to determine activity limitation.
Table 1
– The classification of activity limitation using the OARS scale
ADL problem score
|
Consideration of meal preparation
|
Activity Limitation Classification
|
0 – None
• Requires help with 0 activities and 0 missing values
|
No help required to prepare own meals
|
1 – No impairment
|
1 – Mild
• Requires help with 1–3 activities and 0 missing values; or
• Requires help with 1–2 activities with 1 missing value; or
• Requires help with 1 activity with 2 missing values;
|
No help required to prepare own meals
|
2 – Mild impairment
|
Require help to prepare own meals
|
3 – Moderate impairment
|
2 – Moderate
• Requires help with 4–5 activities with 0 missing values; or
• Requires help with 4 activities with 1 missing value
|
No consideration of help with meal preparation
|
3 – Severe
• Requires help with 6–7 activities with 0 missing values; or
• Requires help with 6 activities with 1 missing value
|
No consideration of help with meal preparation
|
4 – Severe impairment
|
4 – Total
• Requires help with 8–13 activities
|
No consideration of help with meal preparation
|
5 – Total impairment
|
Inconclusive Classification due to missing values
• All other possible combinations
|
–
|
[Excluded from analysis]
|
Health Condition (independent variable of interest) – To determine a diagnosis of diabetes, heart attack, or stroke, participants were asked: 1) Has a doctor ever told you that you have diabetes, borderline diabetes or that your blood sugar is high? 2) Has a doctor ever told you that you have had a heart attack or myocardial infarction? 3) Has a doctor ever told you that you have experienced a stroke or a cerebrovascular accident? Participant responses were classified as: yes or no.
Respondents were divided into eight mutually exclusive groups. The control group included individuals reporting the absence of all of diabetes, myocardial infarction, and stroke. Three experimental groups were developed among those reporting single cardiometabolic diseases: 1) diabetes, 2) myocardial infarction, 3) stroke. Four additional experimental groups were also created for all possible cardiometabolic disease combinations: 1) Diabetes and Stroke, 2) Diabetes and Myocardial Infarction, 3) Stroke and Myocardial Infarction, 4) Diabetes and Stroke and Myocardial Infarction.
Contextual factor covariates – Environment: (i) Social support was measured using the 19-item Medical Outcomes Study (MOS): Social Support Survey.42 This valid and reliable questionnaire consists of four separate social support domains and scores (emotional/informational, tangible, affectionate, and positive social integration), as well as a composite social support index score. Each item is scored on a 5-point response scale (i.e., none of the time, a little of the time, some of the time, most of the time, all of the time). A mean total score is derived for each of the domains and for the composite score. We used the composite score in our analyses, in which higher scores indicate more social support. (ii) Rural or urban location of residence was identified via postal code data.43
Personal: Demographic and socioeconomic variables included for study were age, biological sex (male/female), ethnic background (white, non-white), marital status (single, never married or never lived with a partner; married/living with a partner in a common-law relationship; widowed; divorced / separated), employment status (working, retired), household income (less than $20,000; $20,000 or more, but less than $50,000; $50,000 or more, but less than $100,000; $100,000 or more, but less than $150,000; $150,000 or more), and education (less than secondary school graduation; secondary school graduation, no post-secondary education; some post-secondary education; post-secondary degree/diploma).