Table 2

Results from logistic hierarchical age–period–cohort models for opioid use. Canadian National Population Health Survey, 1994–2011

OR (95% CI)
Model 1Model 2Model 3Model 4
Fixed effects
  Linear age†1.00 (0.99 to 1.01)1.00 (0.99 to 1.01)0.97 (0.97 to 0.98)***0.97 (0.96 to 0.98)***
  Birth cohort (Ref: post-World War I)
   Pre-World War II1.17 (0.95 to 1.44)1.16 (0.93 to 1.45)1.03 (0.80 to 1.32)0.94 (0.75 to 1.18)
   World War II1.48 (1.13 to 1.93)**1.52 (1.15 to 2.01)**1.07 (0.79 to 1.45)1.01 (0.76 to 1.33)
   Older Baby Boom1.93 (1.39 to 2.69)***1.98 (1.41 to 2.77)***1.31 (0.91 to 1.87)1.21 (0.86 to 1.70)
   Younger Baby Boom1.90 (1.29 to 2.81)**1.89 (1.16 to 3.08)**1.29 (0.86 to 1.94)1.16 (0.78 to 1.71)
   Older Generation X2.08 (1.34 to 3.23)**1.98 (1.27 to 3.08)**1.30 (0.83 to 2.03)1.21 (0.78 to 1.87)
   Younger Generation X1.68 (1.02 to 2.76)*1.65 (1.01 to 2.68)*1.02 (0.63 to 1.66)1.08 (0.66 to 1.76)
  Sex (Women)1.44 (1.35 to 1.53)***1.21 (1.14 to 1.29)***1.16 (1.09 to 1.23)**
  Education (Ref: <12 years)
   12–15 years1.23 (1.13 to 1.32)***1.27 (1.17 to 1.38)***1.27 (1.18 to 1.38)***
   16+ years1.03 (0.93 to 1.14)1.29 (1.16 to 1.43)***1.28 (1.15 to 1.43)***
  Income quartiles (Ref: bottom (Q1))
   Q20.92 (0.84 to 1.02)1.06 (0.96 to 1.18)1.07 (0.96 to 1.19)
   Q30.91 (0.82 to 1.01)1.09 (0.98 to 1.22)1.11 (0.98 to 1.26)
   Top (Q4)0.88 (0.82 to 0.95)**1.08 (0.99 to 1.19)‡1.10 (0.99 to 1.23)‡
   Non-response0.86 (0.71 to 1.03)0.89 (0.73 to 1.09)0.92 (0.76 to 1.13)
  BMI (Ref: normal/underweight)§
   Overweight1.07 (1.00 to 1.15)‡1.00 (0.93 to 1.08)1.01 (0.94 to 1.09)
   Obese1.53 (1.42 to 1.65)***1.17 (1.08 to 1.27)***1.18 (1.09 to 1.28)***
  Physical activity (active)0.91 (0.85 to 0.96)***0.99 (0.93 to 1.05)1.00 (0.99 to 1.01)
  Sedentary1.53 (1.43 to 1.63)***1.09 (1.01 to 1.16)*1.04 (0.97 to 1.12)
  Smoking status (Ref: non-smokers)
   Current smokers1.83 (1.70 to 1.98)***1.56 (1.44 to 1.69)***1.47 (1.35 to 1.59)**
   Former smokers1.26 (1.17 to 1.36)***1.17 (1.08 to 1.26)***1.15 (1.06 to 1.24)*
  Alcohol consumption (Ref: not currently)
   Regular drinker1.42 (1.22 to 1.65)***1.51 (1.30 to 1.77)***1.54 (1.32 to 1.80)***
   Occasional drinker1.82 (1.55 to 2.14)***1.64 (1.39 to 1.94)***1.62 (1.36 to 1.93)***
  Pain preventing activities of chronic conditions, n (Ref: none)4.02 (3.71 to 4.36)***3.63 (3.34 to 3.94)***
   12.09 (1.92 to 2.27)***1.16 (1.06 to 1.26)**
   2+4.59 (4.23 to 4.98)***2.06 (1.90 to 2.24)***
  Took antidepressants2.52 (2.27 to 2.81)***
  Took tranquillisers1.60 (1.46 to 1.75)***
Random effects¶
 Individual1.76 (1.67 to 1.85)***1.74 (1.65 to 1.83)***1.33 (1.25 to 1.42)***1.33 (1.24 to 1.41)***
 Period0.09 (0.01 to 0.17)*0.08 (0.00 to 0.17)‡0.06 (0.00 to 0.10)‡0.04 (0.00 to 0.10)
  • ***p<0.0001, **p<0.01, *p<0.05.

  • †p<0.1.

  • ‡Age was centred at 35 years. Models also included a quadratic age term.

  • §Obese (≥30.0), overweight (25.0–29.9), normal/underweight (<25.0).

  • ¶Estimates are variance and 95% CI.

  • BMI, body mass index.