Table 1.

Distribution of cases and controls according to selected characteristics

CharacteristicsCases (n = 1,158)
Controls (n = 1,244)
n (%)n (%)
Region*
    Barcelona218 (18.8)244 (19.6)
    Vallès Occidental/Bages179 (15.5)189 (15.2)
    Elche86 (7.4)84 (6.8)
    Tenerife211 (18.2)217 (17.4)
    Asturias464 (40.1)510 (41.0)
Age (y)*
    <55176 (15.2)205 (16.5)
    55-64247 (21.3)306 (24.6)
    65-69255 (22.0)286 (23.0)
    70-74248 (21.4)243 (19.5)
    ≥75232 (20.0)204 (16)
Gender*
    Male1,012 (87.4)1,080 (86.8)
    Female146 (12.6)164 (13.2)
Education level
    Less than primary532 (45.9)575 (46.2)
    Primary and less than high school451 (38.9)485 (39.0)
    At least high school158 (13.6)164 (13.2)
    Other14 (1.2)15 (1.2)
    Missing1 (0.1)— (—)
No. siblings
    0-2295 (25.5)345 (27.7)
    3-4252 (21.8)273 (21.9)
    ≥5371 (32.0)396 (31.8)
    Missing240 (20.7)230 (18.5)
Smoking status
    Nonsmoker160 (13.8)363 (29.2)
    Occasional47 (4.1)95 (7.6)
    Former472 (40.8)499 (40.1)
    Current474 (40.9)281 (22.6)
    Missing5 (0.4)6 (0.5)
Average lifetime trihalomethane levels (μg/L)
    0-15356 (30.7)423 (34.0)
    16-50414 (35.8)400 (32.2)
    ≥51317 (27.4)350 (28.1)
    Missing71 (6.1)71 (5.7)
Diagnoses of controls
    Ophthalmology diseases15 (1.2)
    Circulatory system diseases46 (3.7)
    Hernia of abdominal cavity450 (36.2)
    Other general surgery/digestive diseases149 (12.0)
    Skin and subcutaneous tissue diseases145 (2.2)
    Male genital organs diseases, hydrocele27 (11.7)
    Fractures300 (24.1)
    Other injuries/orthopedics93 (7.5)
    Other conditions19 (1.5)
  • * Cases and controls were matched on these variables.