Research Article

A Biopsychosocial Profile of Adult Canadians with and without Chronic Back Disorders: A Population-Based Analysis of the 2009-2010 Canadian Community Health Surveys

Table 1

Description of (independent) variables included in analysis.

Variable Description (if applicable) and categories

Sociodemographic characteristics
Age18–34 yrs; 35–49 yrs; 50–64 yrs; ≥65 yrs. Categories based on quartiles and clinical relevance
SexMale; female
EducationLess than secondary; secondary graduation; some postsecondary; postsecondary graduation
Income A StatsCan-derived variable addressing income adequacy. Quintile of adjusted ratio of total household income to the low income cut-off corresponding to household and community size. This variable was unavailable for some respondents, for example, in cases where the person most knowledgeable about the household could not be identified ( 92,669)
ResidenceA StatsCan-derived variable. “Urban” residence includes communities with populations 10,000 people. “Rural” communities are disaggregated into subgroups or metropolitan influenced zones (MIZ) based on the size of commuting flows to any larger urban center [31]
EthnicityCaucasian; Aboriginal (i.e., North American Indian, Métis, or Inuit); other
Marital statusSingle; married or common law; widowed or separated or divorced
Body Mass Index (BMI)Derived from self-reported height and weight
Underweight and normal (<25 kg/m2); overweight (25–29.9 kg/m2);
obese (≥30 kg/m2) [32]

Lifestyle characteristics
Smoking statusNever smoked; former smoker; current smoker
Physical activity-transportation and leisureA StatsCan-derived variable combining leisure time and transportation-physical activity based on estimated total daily energy expenditure variables (kcal/kg/day): active; moderately active; inactive
Sedentary activity durationA StatsCan-derived variable of total number of hours per week spent in sedentary activities (excluding reading): 0–14 hours; 15–24 hours; 25–39 hours; 40 or more hours.* 
This variable was only available for respondents in the provinces of Newfoundland, Manitoba, and British Columbia ( 22,380)

Health characteristics
Number of other comorbidities/chronic conditions Includes “long-term conditions” which are expected to last or have already lasted for 6 months or more and that have been diagnosed by a health professional. No other chronic conditions (other than CBD); 1 or 2 chronic conditions (other than CBD); 3 or more chronic conditions (other than CBD)
Type of other comorbiditiesPresence of top 5 chronic comorbidities associated with CBD: arthritis (excluding fibromyalgia); high blood pressure; migraine headaches; asthma; mood disorders (i.e., depression, bipolar disorder, mania, or dysthymia)
Perceived disability This variable, derived from the Health Utility Index (HUI) [33], considers whether pain prevents a person from performing activities of daily living.
5 categories: no pain or discomfort; pain prevents no activities; pain prevents a few activities; pain prevents some activities; pain prevents most activities
Depression probabilityA StatsCan-derived variable indicating the probability that the respondent would have been diagnosed as having experienced a major depressive episode in the past 12 months, if they had completed the long-form composite international diagnostic interview (CIDI) [34]. This variable was not available for respondents that completed the survey by proxy ( 53,017)
Self-rated stressAbility to handle day-to-day demands: not at all/not very; a bit; quite a bit/extremely*
Self-rated mental healthIndicating the respondent's mental health status based on his/her own judgement: excellent/very good; good; fair/poor*
Self-rated overall healthIndicating the respondent's health status based on his/her own judgement or his/her proxy: excellent/very good; good; fair/poor*
Self-rated work stressIndicating level of stress encountered “most days at work”: not at all/not very; a bit; quite a bit/extremely.* This variable was only available for employed respondents ( 69,992)

Collapsing of these categories was performed to maintain equal-sized categories and consistent categorization for all variables of interest.