Table 2

Logistic regression model reversible and irreversible airflow limitation adjusted for age, gender, and body mass index*

VariablesNormal lung functionReversible airflow limitationIrreversible airflow limitation
No of individuals/casesOR (95% CI)No of individuals/casesOR (95% CI)No of individuals/casesOR (95% CI)
Parental education, primary school/high school versus university1787/7741 (Reference)102/400.85 (0.56 to 1.28)39/170.98 (0.51 to 1.86)
Maternal smoking during pregnancy1789/1971 (Reference)103/141.26 (0.70 to 2.27)39/51.13 (0.44 to 2.96)
Parental asthma1776/3421 (Reference)103/362.24 (1.47 to 3.42)39/70.9 (0.39 to 2.07)
Preterm birth1790/951 (Reference)103/50.91 (0.36 to 2.28)39/31.42 (0.43 to 4.71)
Parental smoking during childhood1790/5261 (Reference)103/331.13 (0.74 to 1.73)39/121.02 (0.51 to 2.05)
Active childhood smoking, ever versus never1786/5861 (Reference)103/330.97 (0.63 to 1.48)39/161.40 (0.73 to 2.69)
RSV infection/pneumonia during infancy1745/1251 (Reference)99/30.40 (0.13 to 1.29)39/93.72 (1.71 to 8.11)
Pneumonia during age 0–4 years1772/1891 (Reference)100/70.62 (0.29 to 1.37)39/92.42 (1.12 to 5.23)
Childhood asthma during age 0–4 years1772/1791 (Reference)100/171.81 (1.04 to 3.13)38/113.26 (1.57 to 7.78)
Childhood asthma during age 4–8 years1606/991 (Reference)91/101.86 (0.93 to 3.70)35/41.73 (0.58 to 5.11)
Childhood asthma during age 8–12 years1589/1081 (Reference)93/121.98 (1.04 to 3.76)36/31.08 (0.32 to 3.64)
Childhood asthma during age 12–16 years1560/1041 (Reference)94/111.84 (0.95 to 3.58)36/41.58 (0.54 to 4.68)
Current asthma1783/2101 (Reference)100/172.32 (1.43 to 3.77)39/112.75 (1.34 to 5.66)
NOx concentration higher than the median†
 Age 0–1 years1767/9111 (Reference)103/450.72 (0.48 to 1.08)39/282.61 (1.28 to 5.35)
 Age 1–4 years1640/8591 (Reference)88/390.72 (0.47 to 1.11)37/241.74 (0.88 to 3.44)
 Age 4–8 years1488/7421 (Reference)81/380.88 (0.56 to 1.38)34/211.71 (0.85 to 3.46)
 Age 8–12 years1637/8321 (Reference)90/360.64 (0.41 to 0.98)37/221.53 (0.78 to 2.99)
 Age 12–16 years1453/7371 (Reference)82/380.82 (0.53 to 1.29)33/222.19 (1.04 to 4.62)
PM10 concentration higher than the median‡
 Age 0–1 years1767/9141 (Reference)103/470.78 (0.52 to 1.17)39/292.96 (1.42 to 6.18)
 Age 1–4 years1640/8401 (Reference)88/430.89 (0.58 to 1.37)37/262.39 (1.16 to 4.92)
 Age 4–8 years1488/7591 (Reference)81/390.91 (0.58 to 1.42)34/221.79 (0.88 to 3.67)
 Age 8–12 years1637/8271 (Reference)90/360.65 (0.42 to 1.00)37/221.54 (0.79 to 3.02)
 Age 12–16 years1453/7421 (Reference)82/360.76 (0.48 to 1.19)33/211.85 (0.89 to 3.84)
  • *Details about the definitions of the covariates are provided in the online supplemental file.

  • †The median NOx concentration for ages 0–1, 1–4, 4–8, 8–12 and 12–16 years were 29.16, 24.21, 18.31, 13.66 and 11.16 µg/m3.

  • ‡The median PM10 concentration for ages 0–1, 1–4, 4–8, 8–12, and 12–16 years were 14.46, 13.28, 13.33, 13.34 and 12.24 µg/m3.

  • NOx, nitrogen oxides; PM10, particulate matter with aerodynamic diameter <10 µm; RSV, respiratory syncytial virus.