Table 4.
Group Examined (ICD-9 Code) | 25 μg Hg (%; Reference Dose) | 50 μg Hg (%) | 75 μg Hg (%) | 100 μg Hg (%) | Odds Ratio per 25 μg Hg (95% CI; P Value) |
---|---|---|---|---|---|
Febrile seizure cases (780.3x) | 329 (6.5) | 463 (9.2) | 3022 (60) | 1224 (24.3) | 0.990 (0.950-1.029; .607) |
Controlsa | 3952 (6.0) | 4297 (6.6) | 42 746 (65.4) | 14 402 (22.0) | |
Unspecified disorders of metabolism cases (277.xx) | 30 (11.7) | 47 (18.3) | 112 (43.6) | 68 (26.4) | 0.687 (0.540-0.835; <.001) |
Controlsa | 4329 (6.0) | 4742 (6.6) | 46 578 (65) | 16 018 (22.4) | |
Cerebral degeneration cases (330.xx or 331.xx) | 117 (5.9) | 158 (8) | 1283 (64.8) | 421 (21.3) | 0.916 (0.859-0.974; <.01) |
Controlsa | 6633 (6.2) | 7184 (6.7) | 66 527 (61.8) | 27 261 (25.3) |
Abbreviations: CI, confidence interval; Hg, mercury; Hib, Haemophilus influenzae type b; ICD-9, International Classification of Disease, Ninth Revision.
aThese controls were followed to the mean age of initial diagnosis plus twice the standard deviation.