Demographic, exposure and clinical characteristics of study participants

 Age, years#46.9±13.6
 Male248 (91)
 BMI, kg·m−2#29.6±6.0
 Ever smokers173 (64)
 Smoking pack-years3 (0–16.4)
 Caucasian ethnicity219 (81)
 Educational qualifications
  Grade school8 (3)
  High school36 (13)
  Trade school128 (47)
  College/university100 (37)
 Marital status
  Single/unmarried82 (30)
  Married/with a partner172 (63)
  Divorced/separated/widowed18 (7)
Exposure history
 Childhood smoke exposure182 (67)
 Parental lung condition74 (27)
 Exposure to mineral fibres#259 (95)
 Use of PPE for mineral fibres#161 (59)
Clinical profile
 Episodes of chest infection in the past 3 years¶,+2 (1–2)
White blood cell profileBaselineFollow-up+
 Neutrophil %58±1059±10
 Eosinophil %3±23±2
 Lymphocyte %30±830±9
 Monocyte %8±28±2
 Lymphocyte/monocyte ratio§3.84±1.313.76±1.45
 Neutrophil/lymphocyte ratio§2.26±1.452.31±1.19

Data are presented as mean±sd or median (interquartile range) for numerical variables, and n (%) for categorical variables. BMI: body mass index; PPE: personal protective equipment. #: data taken at the baseline visit; : data taken at the follow-up visit; +: median interval between baseline and follow-up visit was 3.8 years; §: ratio of absolute count.