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Neuropediatrics 2006; 37(4): 234-240
DOI: 10.1055/s-2006-924577
Original Article

Georg Thieme Verlag KG Stuttgart · New York

Attention-Deficit Hyperactivity Disorder and Blood Mercury Level: a Case-Control Study in Chinese Children

D. K. L. Cheuk1 , V. Wong1
  • 1Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, P. R. China
Further Information

Publication History

Received: January 26, 2006

Accepted after Revision: August 9, 2006

Publication Date:
20 December 2006 (online)

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Corrected by:

Notice of RetractionNeuropediatrics 2008; 39(04): 246-246
DOI: 10.1055/s-0029-1242177

Abstract

Objective: To investigate the association between blood mercury level and attention-deficit hyperactivity disorder (ADHD) in Chinese children in Hong Kong. Methods: Fifty-two children with ADHD aged below 18 years diagnosed by DSM IV criteria without perinatal brain insults, mental retardation or neurological deficits were recruited from a developmental assessment center. Fifty-nine normal controls were recruited from a nearby hospital. Blood mercury levels were measured by cold vapor atomic absorption spectrophotometry. Results: The mean ages of cases and controls were 7.06 and 7.81 years respectively. Boys predominated (case = 44 [84.6 %], control = 44 [74.6 %]). There was significant difference in blood mercury levels between cases and controls (geometric mean 18.2 nmol/L [95 % CI 15.4 - 21.5 nmol/L] vs. 11.6 nmol/L [95 % CI 9.9 - 13.7 nmol/L], p < 0.001), which persists after adjustment for age, gender and parental occupational status (p < 0.001). The geometric mean blood mercury level was also significantly higher in children with inattentive (19.4 nmol/L, 95 % CI 13.3 - 28.5 nmol/L) and combined (18.0 nmol/L, 95 % CI 14.9 - 21.8 nmol/L) subtypes of ADHD. Blood mercury levels were above 29 nmol/L in 17 (26.9 %) cases and 6 (10.2 %) controls. Children with blood mercury level above 29 nmol/L had 9.69 times (95 % CI 2.57 - 36.5) higher risk of having ADHD after adjustment for confounding variables. Conclusion: High blood mercury level was associated with ADHD. Whether the relationship is causal requires further studies.

Key words

attention-deficit Hyperactivity Disorder (ADHD) - mercury - case-control study - children

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Prof. Virginia Wong

Department of Pediatrics and Adolescent Medicine
Queen Mary Hospital
The University of Hong Kong

121 Pokfulam Road

Hong Kong SAR

People's Republic of China

Email: vcnwong@hkucc.hku.hk