Skip to main content

Table 3 Proportion of children with diagnosed autism or extreme levels of autistic traits by proxies for increased mercury exposure

From: Prenatal mercury exposure and features of autism: a prospective population study

Proxy for mercury exposure Diagnosed autism, % (n) Autistic traits, % (n)
Poor social cognition Poor sociability Poor coherence Repetitive behavior
White fish frequencya
 Not at all 1.21 (27) 16.1 (204) 11.6 (191) 12.1 (147) 6.5 (90)
 Once in 2 weeks 1.33 (65) 12.5 (386) 10.4 (397) 9.4 (277) 6.0 (199)
 > once a week 1.37 (69) 11.9 (397) 12.3 (494) 9.7 (314) 5.6 (197)
P (2df) 0.640 < 0.001 0.029 0.026 0.481
Oily fish frequencya
 Not at all 1.23 (63) 13.8 (407) 12.6 (480) 10.9 (308) 6.0 (195)
 Once in 2 weeks 1.49 (60) 13.2 (354) 10.3 (334) 10.0 (256) 5.8 (165)
 > once a week 1.27 (38) 11.1 (226) 11.0 (268) 8.7 (174) 5.9 (126)
P (2df) 0.672 0.017 0.010 0.044 0.971
Shellfish frequencya
 Not at all 1.35 (132) 13.0 (801) 11.0 (834) 10.2 (598) 5.8 (384)
 Any 1.23 (29) 12.1 (186) 13.1 (248) 9.4 (140) 6.3 (102)
P (2df) 0.527 0.352 0.008 0.414 0.438
Had amalgam fillings inserted in pregnancy
 Yes 1.09 (12) 12.8 (222) 10.0 (213) 10.0 (169) 6.7 (127)
 No 1.52 (67) 12.8 (700) 11.7 (786) 9.9 (516) 5.7 (332)
P (1df) 0.283 0.995 0.029 0.920 0.092
Had amalgam fillings removed in pregnancy
 Yes 1.03 (15) 13.8 (155) 9.1 (126) 10.6 (118) 6.0 (73)
 No 1.58 (126) 12.6 (767) 11.7 (873) 9.8 (567) 5.9 (386)
P (1df) 0.110 0.284 0.006 0.405 0.865
Number of amalgams in mouth in pregnancy
 0 1.62 (11) 13.5 (60) 12.4 (77) 11.4 (47) 6.7 (34)
 1–3 1.29 (25) 13.5 (188) 14.0 (250) 8.6 (112) 6.8 (101)
 4+ 1.57 (96) 12.6 (612) 10.4 (600) 9.9 (463) 5.9 (305)
P (2df) 0.677 0.653 < 0.001 0.196 0.355
  1. All associations with P < 0.10 are italicized
  2. df degrees of freedom
  3. aAmount consumed by mother as reported at 32 weeks gestation