Reconcilable Differences: SA
Both annual household income and level of education completed were negatively and significantly associated with the magnitude of SA (3-agonist used, with a consistent gradient across social classes (Fig 2). Adjustment for family size based on the lowincome cutoff did not affect the results. Although the gradient based on education was consistent and the overall associations were significant (p 4 canisters of SA P-agonist in the previous year, and approximately a 35% reduction in the OR for having used > 12 canisters.
The associations between all contextual measures of SES and the magnitude of SA P-agonist use were also significant and consistent in magnitude, independent of method of asthma-severity adjustment.
For every $1,000 increase in median neighborhood household income, there was approximately a 10% decrease in the risk of using greater amounts of SA P-agonist (OR, 0.91; 95% CI, 0.84 to 0.98), and nearly a 5% decrease with every 1% greater prevalence of a having completed a university degree (OR, 0.96; 95% CI, 0.93 to 0.99). The association between SA P-agonist use and neighborhood unemployment rate was also consistent (OR, 1.1; 95% CI, 1.03 to 1.2).
Figure 2. Association between annual household income and education and the use of greater amounts of SA P-agonist, adjusted for asthma severity. * Adjusted for emergency department visit in previous year (yes/no). f Adjusted for emergency department visit in previous year (yes/no), daily ICS use (yes/no), and daily ICS dose. {Model includes emergency department visit in previous year (yes/no), daily ICS use (yes/no), frequency of daytime symptoms, and AQLQ(S) symptom score. §See footnote, Figure 1. Adjusting for asthma severity using the Canadian Asthma Guidelines, the OR for using greater amounts of SA P-agonist for those with annual household incomes between $20,000 and $50,000 was 0.42 (95% CI, 0.20, 0.87) relative to those with annual household incomes $50,000 relative to those with annual household incomes
Table 3—Association Between the No. of Years of Postsecondary Education and the Use of Greater Amounts of SA fi-Agonist, Adjusted for Asthma Severity
High/Intermediate vs |
High vs Intermediate/ |
|
Low Use OR |
Low Use OR |
|
Severity Adjustment |
(95% CI) |
(95% CI) |
Canadian |
0.83 (0.72-0.95) |
0.66 (0.52-0.83) |
guidelines* |
||
ASSf |
0.80 (0.69-0.93) |
0.67 (0.53-0.86) |
CLDSIf |
0.81 (0.70-0.94) |
0.67 (0.53-0.86) |
Ng Scoref |
0.78 (0.68-0.91) |
0.62 (0.48-0.80) |
Stepwise model{ |
0.82 (0.70-0.94) |
0.65 (0.50-0.84) |