Table 2 Hazard ratios for asthma during a 10-year follow-up (2004–2013) according to age, economic status, health behaviours and BMI by sex

 40–49

8924

–

–

10,602

–

–

 50–59

7451

1.55 (1.51–1.60)

1.53 (1.48–1.58)

8547

1.28 (1.24–1.32)

1.24 (1.21–1.28)

 60–69

6466

2.47 (2.39–2.55)

2.38 (2.30–2.46)

7119

1.53 (1.49–1.58)

1.48 (1.44–1.53)

  ≥ 70

2118

3.70 (3.53–3.88)

3.46 (3.30–3.64)

2144

1.61 (1.54–1.69)

1.58 (1.51–1.66)

 Self-employed insured

8927

–

–

13,309

–

–

 Employed insured

16,000

0.78 (0.76–0.80)

0.92 (0.89–0.94)

15,045

0.96 (0.94–0.98)

1.00 (0.97–1.02)

 Medical aid beneficiary

32

2.20 (1.56–3.12)

1.69 (1.20–2.40)

58

1.51 (1.17–1.95)

1.38 (1.06–1.78)

 Low

6913

–

–

10,520

–

–

 Medium

9193

0.82 (0.80–0.85)

0.95 (0.92–0.98)

9756

0.99 (0.96–1.02)

0.99 (0.96–1.01)

 High

8853

0.80 (0.77–0.82)

0.97 (0.94–1.00)

8136

0.98 (0.95–1.01)

1.00 (0.98–1.03)

 Underweight (< 18.5 kg/m²)

763

1.57 (1.46–1.69)

1.32 (1.23–1.43)

554

1.02 (0.94–1.10)

0.94 (0.87–1.03)

 Normal (18.5–< 23 kg/m²)

8494

–

–

9571

–

 Overweight (23–< 25 kg/m²)

6910

0.94 (0.91–0.97)

1.00 (0.96–1.03)

7390

1.14 (1.11–1.17)

1.11 (1.07–1.14)

 Obesity (25–< 30 kg/m²)

8223

0.95 (0.93–0.98)

1.04 (1.01–1.07)

9657

1.31 (1.27–1.34)

1.24 (1.21–1.28)

 Severe obesity (≥30 kg/m²)

569

1.08 (1.00–1.18)

1.23 (1.13–1.34)

1240

1.50 (1.42–1.58)

1.40 (1.32–1.48)

 Unknown

1158

0.95 (0.90–1.01)

1.05 (0.98–1.13)

1093

1.03 (0.97–1.09)

1.00 (0.92–1.10)

 Never smoker

10,474

–

–

26,081

–

–

 Past smoker

3803

0.97 (0.94–1.01)

1.11 (1.07–1.15)

269

1.09 (0.97–1.23)

1.10 (0.98–1.24)

 Current smoker

9524

0.89 (0.87–0.92)

1.07 (1.04–1.10)

969

1.43 (1.34–1.53)

1.42 (1.33–1.51)

 Unknown

369

0.89 (0.80–0.99)

0.85 (0.76–0.96)

728

1.05 (0.97–1.13)

1.00 (0.90–1.12)

 None

9749

–

–

22,950

–

–

  < Twice a week

10,040

0.74 (0.71–0.76)

0.87 (0.84–0.89)

4180

0.93 (0.90–0.97)

0.99 (0.95–1.02)

  ≥ Three times a week

4801

0.85 (0.82–0.88)

0.86 (0.83–0.90)

554

1.07 (0.98–1.16)

1.05 (0.96–1.14)

 Unknown

798

0.97 (0.90–1.04)

1.07 (0.98–1.16)

866

1.04 (0.97–1.11)

1.04 (0.96–1.13)

 None

12,572

–

–

18,364

–

–

  < Twice a week

6518

0.82 (0.80–0.85)

0.96 (0.93–0.99)

4503

0.97 (0.94–1.01)

1.02 (0.99–1.06)

  ≥ Three times a week

5071

0.94 (0.91–0.97)

0.96 (0.93–0.99)

4679

1.03 (1.00–1.07)

1.05 (1.02–1.08)