Table 2

 Number of subjects (controls) by level of exposure to different indices of exposure to THM*

Level of exposureWater consumption at home (ingestion), μg/day
UnexposedLowMediumHighTotal
0>0–10.0>10.0–35.0>35.0
*Analysis limited to controls with ⩾70% of known ingestion and residential THM exposure. Ingestion and bathing/showering THM exposure metrics are the average of the exposure window from age 15 until the time of interview. THM exposure categories are defined by quartiles.
†Missing information on swimming pools for 268 subjects.
Bathing/showering (dermal absorption/inhalation), μg/l*min/day
Low exposed (<50)29 (6%)56 (12%)13 (3%)5 (1%)103 (22%)
Medium–low (50–<167)27 (6%)41 (9%)51 (11%)17 (4%)136 (30%)
Medium–high (167–<333)17 (4%)17 (4%)25 (5%)39 (8%)98 (21%)
High (⩾333)32 (7%)11 (2%)27 (6%)53 (12%)123 (27%)
Total105 (23%)125 (27%)116 (25%)114 (25%)460 (100%)
Swimming pool attendance (dermal absorption/inhalation)†
Never128 (23%)125 (23%)121 (22%)100 (18%)474 (87%)
Ever14 (3%)16 (3%)16 (3%)26 (5%)72 (13%)
Total142 (26%)141 (26%)137 (25%)126 (23%)546 (100%)