Table 1 Characteristics of the subjects at the beginning of follow-up
Exposure to waste water
No (n = 446)Yes (n = 332)
Age (years)42 (16–68)46 (17–66)
Male gender417 (94)331 (100)
Educational level
    Low104 (24)39 (12)
    Middle323 (73)290 (87)
    High15 (3)3 (1)
Nationality
    Swiss342 (77)302 (91)
    Other countries104 (23)30 (9)
Country of childhood
    Switzerland332 (74)299 (90)
    Other countries114 (26)33 (10)
Smoking
    Never178 (40)99 (30)
    Former104 (23)101 (30)
    Current162 (37)132 (40)
    Pack-years*17.0 (0.1–129)20.0 (0.25–84.0)
Alcohol
    No/only socially296 (67)219 (66)
    Daily148 (33)112 (34)
GGT activity (%)†24.4 (8.1–167.4)29.1 (7.0–800)
Duration of follow-up (years)3.7 (0.2–5.1)3.9 (0.2–5.2)
Job change during follow-up because of any health problem33 (8)23 (7)
Lifelong exposure to sewage at baseline (years)‡0.0 (0.0–31.0)11.0 (0.5–39.0)
Use of suitable gloves§NA218 (66)
Use of an adequate mask§NA88 (27)
Shift work
    Without night shift2 (–)5 (2)
    With night shift8 (2)10 (3)
  • Values are as ascertained at baseline with the exception of the duration of follow-up and any job change because of health problems which relate to the entire follow-up period. Figures are median (range) or number (percentage). NA, not applicable.

  • *Pack-years: median and percentiles calculated in the subgroup of ex- and current cigarette smokers only; †γ-glutamyltransferase (GGT) activity expressed in per cent of the upper limit of the reference range according to sex (male: 86 U/l, female: 47 U/l); ‡lifelong exposure to sewage: 17 workers had only a former exposure. Median time elapsed since last exposure was 10 (0.5–31) years; §see Methods section for definitions of suitable gloves and adequate masks.