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Table 5 Effect modification of Cox HRs by sex, ageǂ, smoking, obesity, and fruit/vegetable and alcohol consumption

From: Risk estimates of mortality attributed to low concentrations of ambient fine particulate matter in the Canadian community health survey cohort

    95 % CI    95 % CI Cochran’s Q
Cause of death Deaths HR Lower Upper Deaths HR Lower Upper Q p
  Females (n = 161,700) Males (n = 137,800)   
Non-accidental 12,700 *1.181 1.088 1.282 13,000 *1.344 1.239 1.457 4.829 0.028
Circulatory 4,100 1.109 0.959 1.282 4,300 *1.268 1.101 1.459 1.687 0.194
Respiratory 1,100 1.323 0.998 1.754 1,300 *1.698 1.307 2.206 1.617 0.204
  <75 years oldǂ (n = 266,600) ≥75 years oldǂ (n = 32,900)   
Non-accidental 13,100 *1.248 1.151 1.353 12,600 *1.237 1.140 1.342 0.023 0.880
Circulatory 3,500 *1.239 1.058 1.450 4,900 1.100 0.965 1.254 1.295 0.255
Respiratory 1,000 *1.553 1.158 2.083 1,300 *1.461 1.136 1.878 0.096 0.757
  Ever Smoked (n = 215,100) Never Smoked (n = 84,100)   
Non-accidental 19,400 *1.231 1.152 1.315 6,300 *1.397 1.242 1.571 3.381 0.066
Circulatory 6,000 *1.164 1.034 1.311 2,300 *1.287 1.060 1.563 0.749 0.387
Respiratory 1,900 *1.449 1.174 1.788 400 *1.966 1.236 3.129 1.376 0.241
  Obese I and II (n = 78,900) Normal weight (n = 93,700)   
Non-accidental 6,200 *1.215 1.077 1.370 8,700 *1.264 1.147 1.394 0.250 0.617
Circulatory 2,100 1.110 0.903 1.364 2,700 1.125 0.945 1.339 0.009 0.922
Respiratory 500 *1.757 1.146 2.694 900 *1.408 1.041 1.905 0.688 0.407
  Obese II (n = 24,200)b   Normal weight (n = 93,700)   
Non-accidental 1,900 1.142 0.919 1.419 8,700 *1.264 1.147 1.394 0.698 0.403
Circulatory 700 0.888 0.609 1.294 2,700 1.125 0.945 1.339 1.247 0.264
  <5 fruit/veg servings (n = 153,200) ≥5 fruit/veg servings (n = 101,100)   
Non-accidental 12,900 *1.217 1.124 1.318 8,500 *1.199 1.087 1.322 0.054 0.817
Circulatory 4,100 1.098 0.954 1.263 2,900 *1.322 1.117 1.563 2.764 0.096
Respiratory 1,200 *1.421 1.091 1.852 700 *1.505 1.078 2.101 0.070 0.792
  Regular drinker (n = 141,700) Not regular drinkera (n = 91,800)   
Non-accidental 9,600 *1.280 1.168 1.403 13,300 *1.280 1.182 1.387 <0.001 1.000
Circulatory 2,900 *1.257 1.065 1.483 4,600 *1.201 1.048 1.376 0.174 0.677
Respiratory 800 *1.473 1.070 2.027 1,300 *1.449 1.120 1.875 0.006 0.938
  1. All models are stratified by age (5 year categories) and sex, and adjusted for the following covariates: immigrant status, visible minority status, Aboriginal status, marital status, educational attainment, income adequacy quintile, employment, body mass index, fruit and vegetable consumption, smoking, and alcohol. For each comparison, the stratum or covariate being compared was not included as a stratum/covariate in the model (i.e., smoking was not included as a covariate in the smoking comparison)
  2. ǂAge at entry into Cohort
  3. +Cochran’s Q test for significant difference of HR between groups
  4. *Significant HR (p < 0.05)
  5. aIncludes occasional, former, or never drinker
  6. bRespiratory mortality not shown; mortality for obese II: n < 200