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Table 1 Description of the study population

From: Air pollution and airway resistance at age 8 years – the PIAMA birth cohort study

Variable n/N (%)
Female sex 504/983 (51)
Parental education
 Low 110/981 (11)
 Medium 343/981 (35)
 High 528/981 (54)
Parental allergy 739/983 (75)
Maternal smoking during pregnancy 147/974 (15)
Smoking in the child’s home
 First year of life 233/980 (24)
 Currenta 138/916 (15)
Mold/dampness in living room and/or child’s bedroom
 First year of life 69/970 (7)
 Currenta 51/910 (6)
Pets in the child’s home
 First year of life 446/981 (45)
 Currenta 454/900 (50)
Use of gas for cooking
 First year of life 788/965 (82)
 Currenta 732/958 (76)
Unvented gas water heater
 First year of life 44/931 (5)
 Currenta 21/932 (2)
Older siblings 469/982 (48)
Dutch nationality 913/964 (95)
Asthmab 103/957 (11)
Did not move house since birth 505/973 (52)
  1. aAge 8 years except for use of gas for cooking and unvented gas water heater, where no information was available from the 8-year questionnaire and data from the 5-year questionnaire were used
  2. bDefined as 2 out of the 3 following criteria: asthma ever, wheeze in the past 12 months and prescription of asthma medication in the past 12 months