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Table 2 Asthma incidence and results from Cox regression analysis by baseline socio-demographic and health behavior characteristics

From: Asthma incidence and risk factors in a national longitudinal sample of adolescent Canadians: a prospective cohort study

  Person-years of follow-up Number of asthma cases Incidence per 1000 person-years (95% CI) Crude HR (95% CI) Adjusted HR* (95% CI)
Sex      
   Male 10,766,510 70,770 6.6 (4.5-9.8) 1.00 1.00
   Female 10,508,380 138,290 13.2 (9.7-18.2) 1.99 (1.23-3.23) 2.13 (1.26-3.62)
Age group      
   12-13 6,007,840 53,130 8.8 (5.6-14.7) 1.00 1.00
   14-15 6,044,580 56,290 9.3 (6.0-15.1) 1.03 (0.53-2.00) 1.09 (0.55-2.16)
   16-18 9,222,480 99,640 10.8 (7.6-15.8) 1.18 (0.65-2.16) 1.16 (0.63-2.16)
Area of residence      
   Urban 17,056,720 182,260 10.7 (8.3-14.0) 1.00 1.00
   Rural 4,218,170 26,810 6.4 (3.4-13.2) 0.61 (0.27-1.35) 0.58 (0.25-1.35)
Income      
   High 3,363,690 37,290 11.1 (6.4-20.9) 1.00 1.00
   Middle 14,358,250 123,840 8.6 (6.5-11.7) 0.78 (0.40-1.54) 0.72 (0.36-1.44)
   Low 3,552,950 47,940 13.5 (7.6-26.2) 1.19 (0.53-2.69) 1.13 (0.48-2.66)
BMI status      
   Normal 16,839,660 174,930 10.4 (8.0-13.7) 1.00 1.00
   Overweight or obese 4,435,230 34,130 7.7 (4.6-14.3) 0.76 (0.39-1.45) 0.73 (0.37-1.46)
Passive smoking exposure      
   Absent 12,860,340 93,130 7.2 (5.0-11.0) 1.00 1.00
   Present 8,414,550 115,930 13.8 (10.2-18.9) 1.88 (1.19-2.98) 2.06 (1.27-3.34)
Personal smoking      
   Never/Former 17,730,630 75,530 9.9 (7.6-13.1) 1.00 1.00
   Occasionally/Daily 3,544,260 33,530 9.5 (5.4-17.7) 0.95 (0.48-1.87) 0.67 (0.34-1.30)
Physical exercise      
   Inactive 18,263,280 175,820 9.6 (7.4-12.7) 1.00 1.00
   Active 3,011,620 33,250 11.0 (6.2-21.1) 1.13 (0.55-2.35) 1.27 (0.57-2.83)
  1. *Adjusted for each variable in the table.
  2. †Signifies p<0.05.