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Table 1 Selection, enrollment, and initial and final exposure status of study subjects

From: Long-term health effects of early life exposure to tetrachloroethylene (PCE)-contaminated drinking water: a retrospective cohort study

  Initial exposure status  
  Index subject Older sibling  
  Exposed Unexposed Unexposed Total
Selected 1910 1928 1202 5040
Excluded during enrollment     
Deceased 35 40 36 111
  Parent refused participation 199 148 80 427
  Never located 113 149 70 332
  No response 871 887 536 2294
  Refused 73 78 36 187
Returned questionnaire 619 626 444 1689
  Percent of selected 32.4% 32.5% 36.9% 33.5%
  Percent of located 39.6% 39.3% 43.7% 40.5%
Excluded during exposure assessment     
  Inadequate residential history 15 37 29 81
  Off-Cape address in potential 19 27 50 96
  VL/AC town
Available for analysis 585 562 365 1512
Percent of selected 30.6% 29.1% 30.4% 30.0%
Final exposure status     
  Both prenatal and early 561 160 110 831
  childhood exposure
  Only early childhood 7 42 85 134
  Exposure
  Unexposed 17 360 170 547