Background
Methods
Study area and population
Questionnaire and clinical examinations
Definitions
Analyses
Results
Prevalence of asthma, rhinitis, eczema and risk factors
Age (years) | Sex | |||||||
---|---|---|---|---|---|---|---|---|
18–39 | 40–59 | 60–77 | P value1
| Men | Women | P value2
| Total (95 % CI) | |
Current asthma | 12.3 | 13.4 | 9.4 | 0.216 | 10.1 | 13.2 | 0.122 | 11.8 (9.9–13.6) |
Asthma ever | 17.8 | 16.2 | 11.8 | 0.024 | 14.0 | 16.2 | 0.328 | 15.2 (13.1–17.3) |
Current rhinitis | 48.8 | 43.8 | 36.6 | 0.001 | 44.5 | 41.4 | 0.314 | 42.8 (40.0–45.7) |
Rhinitis ever | 53.7 | 48.5 | 39.5 | <0.001 | 50.0 | 44.4 | 0.060 | 47.0 (44.2–50.0) |
Current eczema | 12.9 | 17.0 | 9.7 | 0.167 | 11.3 | 15.4 | 0.040 | 13.5 (11.5–15.4) |
Eczema ever | 49.1 | 46.8 | 38.2 | 0.003 | 36.5 | 51.6 | <0.001 | 44.6 (41.8–47.5) |
Asthma medication 12 m | 11.0 | 12.5 | 10.7 | 0.864 | 9.8 | 13.0 | 0.098 | 11.5 (9.7–13.4) |
Rhinitis medication 12 m | 33.7 | 30.8 | 19.9 | <0.001 | 27.1 | 28.9 | 0.515 | 28.1 (25.5–30.6) |
Allergic sensitization | 40.9 | 31.0 | 18.6 | <0.001 | 36.0 | 24.2 | <0.001 | 29.7 (27.0–32.4) |
Smoking
| ||||||||
Never smoker | 70.6 | 52.1 | 49.5 | <0.001
3
| 58.5 | 54.5 | 0.015
3
| 56.4 (53.5–59.2) |
Ex-smoker | 11.0 | 29.7 | 37.6 | 28.3 | 26.0 | 27.1 (24.5–29.6) | ||
Current smoker | 18.4 | 18.2 | 12.9 | 13.1 | 19.5 | 16.5 (14.4–18.7) | ||
Family history
| ||||||||
Asthma | 23.8 | 20.2 | 15.0 | 0.004 | 15.8 | 22.6 | 0.004 | 19.5 (17.2–21.8) |
Rhinitis | 42.9 | 35.2 | 14.0 | <0.001 | 25.3 | 35.3 | <0.001 | 30.6 (27.9–33.4) |
Asthma and rhinitis | 16.7 | 12.6 | 4.7 | <0.001 | 7.9 | 14.1 | 0.002 | 11.2 (9.4–13.1) |
Asthma or rhinitis | 49.8 | 42.1 | 24.0 | <0.001 | 32.9 | 43.1 | <0.001 | 38.4 (35.6–41.2) |
Body mass index
| ||||||||
Underweight (<20) | 10.4 | 3.0 | 1.0 | <0.001
3
| 1.5 | 7.0 | <0.001
3
| 4.4 (3.3–5.6) |
Normal (20–25) | 54.9 | 34.7 | 28.0 | 33.2 | 42.4 | 38.1 (35.4–40.9) | ||
Overweight (25–30) | 26.1 | 45.0 | 52.4 | 50.7 | 34.8 | 42.2 (39.3–45.0) | ||
Obese (>30) | 8.6 | 17.2 | 18.6 | 14.6 | 15.9 | 15.3 (13.2–17.3) | ||
Occupational GDF | 24.3 | 24.6 | 25.3 | 0.750 | 36.2 | 14.9 | <0.001 | 24.7 (22.3–27.2) |
Metropolitan domicile | 70.6 | 50.9 | 52.4 | <0.001 | 54.8 | 58.6 | 0.214 | 57.0 (54.0–60.0) |
Raised on a farm | 7.7 | 11.8 | 19.9 | <0.001 | 13.9 | 12.8 | 0.604 | 13.3 (11.4–15.3) |
Unadjusted risk factors for asthma, rhinitis and eczema
Independent variables | Dependent variables | ||
---|---|---|---|
Current asthma | Current rhinitis | Current eczema | |
OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | |
Age (years)
| |||
60–77 | 1 | 1 | 1 |
40–59 | 1.48 (0.96–2.29) | 1.34 (1.02–1.77) | 1.91 (1.26–2.90) |
18–39 | 1.34 (0.83–2.17) | 1.65 (1.22–2.22) | 1.38 (0.86–2.20) |
Sex
| |||
Men | 1 | 1 | 1 |
Women | 1.34 (0.94–1.93) | 0.88 (0.70–1.11) | 1.45 (1.05–2.00) |
Smoking
| |||
Never smoker | 1 | 1 | 1 |
Ex-smoker | 0.86 (0.56–1.31) | 0.96 (0.73–1.26) | 1.28 (0.87–1.89) |
Current smoker | 1.04 (0.64–1.70) | 1.15 (0.83–1.59) | 1.46 (0.93–2.28) |
Family history
| |||
None | 1 | 1 | 1 |
Asthma | 1.33 (0.58–3.05) | 0.72 (0.42–1.25) | 1.44 (0.72–2.85) |
Rhinitis | 1.49 (0.88–2.51) | 3.05 (2.20–4.24) | 1.32 (0.83–2.08) |
Both | 5.41 (3.38–8.64) | 3.32 (2.23–4.95) | 1.82 (1.10–3.00) |
Degree of urbanization
| |||
Rural area (<500 inh.) | 1 | 1 | 1 |
Village (500–2000 inh.) | 0.88 (0.29–2.65) | 1.23 (0.65–2.37) | 0.97 (0.35–2.74) |
Small town (2000–10,000 inh.) | 1.28 (0.55–3.00) | 1.01 (0.58–1.75) | 1.16 (0.51–2.68) |
Larger town (>10,000 inh.) | 1.29 (0.67–2.48) | 1.41 (0.94–2.11) | 1.39 (0.74–2.61) |
Occupational exposure to GDF | |||
No | 1 | 1 | 1 |
Yes | 1.70 (1.16–2.49) | 1.10 (0.84–1.44) | 1.73 (1.21–2.48) |
Metropolitan domicile
| |||
No | 1 | 1 | 1 |
Yes | 0.86 (0.60–1.23) | 1.03 (0.81–1.30) | 1.21 (0.86–1.70) |
Body mass index
| |||
Normal | 1 | 1 | 1 |
Underweight | 1.17 (0.47–2.88) | 1.34 (0.75–2.38) | 1.24 (0.56–2.78) |
Overweight | 1.07 (0.71–1.63) | 0.94 (0.73–1.22) | 0.98 (0.67–1.44) |
Obese | 2.10 (1.29–3.40) | 1.79 (1.26–2.53) | 1.43 (0.89–2.31) |
Allergic sensitization
| |||
No | 1 | 1 | 1 |
Yes | 4.02 (2.76–5.84) | 5.77 (4.34–7.67) | 1.35 (0.94–1.93) |
Independent variables | Dependent variables | ||
---|---|---|---|
Current asthma | Current rhinitis | Current eczema | |
OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | |
Raised on a farm
| |||
No | 1 | 1 | 1 |
Yes | 0.84 (0.48–1.45) | 0.54 (0.38–0.78) | 0.45 (0.24–0.85) |
Number of siblings
| |||
0 | 1 | 1 | 1 |
1 | 3.06 (1.29–7.25) | 1.37 (0.92–2.06) | 0.76 (0.45–1.29) |
2 or more | 2.76 (1.17–6.49) | 1.32 (0.89–1.97) | 0.59 (0.35–0.99) |
Childhood daycare
| |||
No | 1 | 1 | 1 |
Yes | 1.14 (0.80–1.63) | 1.40 (1.11–1.77) | 1.48 (1.06–2.07) |
Childhood smoke exposure
| |||
No | 1 | 1 | 1 |
Yes | 1.05 (0.73–1.50) | 0.91 (0.72–1.15) | 1.52 (1.06–2.16) |
Maternal smoking in pregnancy
| |||
No | 1 | 1 | 1 |
Yes | 0.70 (0.35–1.37) | 1.04 (0.70–1.54) | 1.89 (1.13–3.14) |
Furry animals in childhood
| |||
Yes | 1 | 1 | 1 |
No | 1.19 (0.83–1.70) | 1.05 (0.75–1.49) | 1.24 (0.98–1.57) |
Childhood airway infection
| |||
No | 1 | 1 | 1 |
Yes | 2.35 (1.57–3.51) | 0.94 (0.73–1.23) | 1.34 (0.92–1.94) |
Shared bedroom in childhood
| |||
No | 1 | 1 | 1 |
Yes | 1.22 (0.85–1.76) | 0.91 (0.72–1.16) | 0.99 (0.70–1.39) |
Birth weight
| |||
3000–4000 g | 1 | 1 | 1 |
Less than 2500 g | 2.00 (0.89–4.50) | 1.22 (0.65–2.31) | 0.96 (0.39–2.35) |
2500–3000 g | 1.41 (0.81–2.45) | 1.04 (0.71–1.52) | 1.21 (0.73–1.99) |
More than 4000 g | 0.72 (0.36–1.44) | 0.89 (0.60–1.31) | 0.54 (0.28–1.04) |
Level of education
| |||
Secondary school or less | 1 | 1 | 1 |
High school | 1.00 (0.59–1.67) | 1.10 (0.79–1.54) | 1.49 (0.91–2.43) |
University | 1.09 (0.67–1.78) | 1.15 (0.84–1.58) | 1.13 (0.69–1.84) |
Adjusted risk factors for asthma, rhinitis and eczema
Independent variables | Dependent variables | ||
---|---|---|---|
Current asthma | Current rhinitis | Current eczema | |
OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | |
Age (years)
| |||
60–77 | 1 | 1 | 1 |
40–59 | 1.00 (0.61–1.63) | 0.88 (0.64–1.23) | 1.51 (0.95–2.38) |
18–39 | 0.73 (0.39–1.37) | 0.92 (0.61–1.41) | 0.88 (0.49–1.57) |
Sex
| |||
Men | 1 | 1 | 1 |
Women | 1.77 (1.15–2.70) | 0.91 (0.69–1.21) | 1.71 (1.17–2.51) |
Family history
| |||
None | 1 | 1 | 1 |
Asthma | 1.29 (0.55–3.04) | 0.61 (0.34–1.10) | 1.45 (0.72–2.94) |
Rhinitis | 1.16 (0.66–2.03) | 2.58 (1.79–3.72) | 1.25 (0.77–2.04) |
Both | 4.33 (2.57–7.30) | 2.76 (1.77–4.31) | 1.61 (0.94–2.76) |
Occupational exposure to GDF
| |||
No | 1 | 1 | 1 |
Yes | 1.85 (1.20–2.87) | 1.03 (0.76–1.41) | 2.08 (1.40–3.08) |
Raised on a farm
| |||
No | 1 | 1 | 1 |
Yes | 0.96 (0.52–1.77) | 0.64 (0.42–0.96) | 0.51 (0.27–0.99) |
Body mass index
| |||
Normal | 1 | 1 | 1 |
Underweight | 0.95 (0.36–2.55) | 1.42 (0.74–2.71) | 1.00 (0.44–2.30) |
Overweight | 1.04 (0.65–1.67) | 1.04 (0.77–1.41) | 1.02 (0.68–1.54) |
Obese | 1.95 (1.13–3.36) | 2.30 (1.53–3.46) | 1.34 (0.80–2.24) |
Allergic sensitization
| |||
No | 1 | 1 | 1 |
Yes | 4.11 (2.71–6.25) | 5.11 (3.77–6.93) | 1.26 (0.85–1.85) |
Number of siblings
| |||
0 | 1 | 1 | 1 |
1 | 3.09 (1.25–7.63) | 1.16 (0.74–1.81) | 0.72 (0.42–1.24) |
2 or more | 2.51 (1.02–6.15) | 1.15 (0.74–1.79) | 0.55 (0.32–0.94) |
Childhood daycare
| |||
No | 1 | 1 | 1 |
Yes | 0.92 (0.59–1.44) | 1.11 (0.81–1.52) | 1.40 (0.94–2.10) |