Table 1

Baseline characteristics of the study population

Population characteristicsTotal population at baseline,
n=79 604
Age (years), mean (SD)44 (13)
Female sex, %60.2
Follow-up duration (years), mean (SD)4 (1)
Body mass index (kg/m2), mean (SD)26 (4)
Smoking never smokers, N(%)35 218 (47.3)
Ex-smokers, N(%)24 429 (32.8)
Current smokers, N(%)14 783 (19.5)
Education low, N(%)11 955 (15.8)
Medium, N(%)38 958 (51.5)
High, N(%)23 192 (30.7)
Unclassifiable, N(%)1380 (1.8)
Monthly income low, N(%)11 191 (15.2)
Medium, N(%)19 922 (27.0)
High, N(%)32 289 (43.8)
Unknown, N(%)10 376 (14.1)
Anti-inflammatory medication, %27.5
Asthma, %8.2
C reactive protein (mg/dL), median (IQR)1.20 (2.20)
Eosinophils (count ×106/L), median (IQR)150 (130)
Neutrophils (count ×106/L), median (IQR)3100 (1,390)
Δ eosinophil (count ×106/L), median (IQR)10 (80)
Δ neutrophil (count ×106/L), median (IQR)60 (1,010)
Allergens exposed, %31.5
Reactive chemicals exposed, %32.1
Pesticides exposed, %8.5
Micro-organisms exposed, %6.8
  • Δ-Difference in numbers of eosinophil and neutrophil between baseline and follow-up.

  • Education: low education (No training, primary education, lower or pre-vocational education); medium education (General secondary education, secondary vocational or professional guiding, preuniversity education); high education (Higher professional or university degree); Unclassifiable (Subjects with other than above-mentioned education).

  • Monthly income: low income (monthly net income ≤ €1500); medium income (monthly net income between €1500 and €2500); high income (monthly net income ≥ €2500); unknown (I don’t know/ I don’t want to say).

  • Smoking: never smokers (Never smoked or smoked for < 1 year); ex-smokers (Smoked for ≥ 1 yearand stopped smoking for ≥ 1 month); current smokers (Current smoker or stopped smoking < 1 month)

  • Anti-inflammatory medication: prescribed use of steroids and/or non-steroidal anti-inflammatory drugs.

  • IQR, Interquartile range; SD, Standard deviation .