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

 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

 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

 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

 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

 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

 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