PMID- 16301096 OWN - NLM STAT- MEDLINE DCOM- 20090304 LR - 20220409 IS - 0892-0362 (Print) IS - 0892-0362 (Linking) VI - 27 IP - 6 DP - 2005 Nov-Dec TI - Chronic low-level mercury exposure, BDNF polymorphism, and associations with cognitive and motor function. PG - 781-96 AB - Potential cognitive and motor effects from exposure to elemental mercury (Hg(0)) were examined in the presence and absence of a polymorphism (Val66Met) in brain-derived neurotrophic factor (BDNF). A group of 194 male dentists (DDs) and 233 female dental assistants (DAs) were occupationally exposed to mercury and had no history of kidney or nervous system disorders. Acute exposure was measured using spot urinary Hg (HgU) concentrations (average 3.32 and 1.98 microg/l, respectively) and indices of chronic occupational exposure (26.3 and 14.9 years, respectively, weighted for historical exposures). The BDNF status was 68% and 66% wild type, 26% and 30% single substitution, and 5% and 4% full mutation for DDs and DAs, respectively. DDs and DAs were evaluated separately. Regression analyses controlled for age, premorbid intelligence, alcohol consumption, and education. Statistically significant adverse associations with HgU (p<.05) were found for nine measures among DDs (Digit Span (Forward), Digit and Spatial Span(Backward), Visual Reproduction, Finger Tapping(Dominant, Alternate, and Alternate Partialed), Hand Steadiness, and Tracking), and eight measures among DAs (Digit Span(Forward), Visual Reproduction, Pattern Discrimination(Rate), Symbol Digit(Rate), Trailmaking B, Finger Tapping(Dominant and Alternate Partialed), and Hand Steadiness). The BDNF status was associated with four measures in DDs and three measures in DAs. Joint effects were found for Finger Tapping(Alternate and Alternate Partialed) in DDs and Hand Steadiness and Trailmaking B in DAs. Joint effects were additive in all cases. Performance on verbal intelligence and reaction time were not associated with either HgU or BDNF status. A test of threshold effect for the association of Hand Steadiness with HgU demonstrated no lower boundary in both DDs and DAs. No associations were observed with estimates of chronic mercury exposure. Our findings are applicable to exposure levels of the general population and identify a potentially vulnerable group with a BDNF polymorphism. FAU - Echeverria, Diana AU - Echeverria D AD - Battelle Centers for Public Health Research and Evaluation, Seattle, WA 98109, USA. echeverr@battelle.org FAU - Woods, James S AU - Woods JS FAU - Heyer, Nicholas J AU - Heyer NJ FAU - Rohlman, Dianne S AU - Rohlman DS FAU - Farin, Federico M AU - Farin FM FAU - Bittner, Alvah C Jr AU - Bittner AC Jr FAU - Li, Tingting AU - Li T FAU - Garabedian, Claire AU - Garabedian C LA - eng GR - 5 R01 DE11712/DE/NIDCR NIH HHS/United States GR - P30ES07033/ES/NIEHS NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't PL - United States TA - Neurotoxicol Teratol JT - Neurotoxicology and teratology JID - 8709538 RN - 0 (Brain-Derived Neurotrophic Factor) RN - FXS1BY2PGL (Mercury) SB - IM MH - Brain-Derived Neurotrophic Factor/*genetics MH - Cognition/*drug effects MH - Dental Assistants MH - Dentists MH - Humans MH - Mercury/urine MH - Mercury Poisoning, Nervous System/*psychology MH - Motor Activity/*drug effects MH - Neuropsychological Tests MH - Occupational Exposure MH - Polymorphism, Genetic MH - Regression Analysis EDAT- 2005/11/23 09:00 MHDA- 2009/03/05 09:00 CRDT- 2005/11/23 09:00 PHST- 2004/10/06 00:00 [received] PHST- 2005/08/22 00:00 [revised] PHST- 2005/08/22 00:00 [accepted] PHST- 2005/11/23 09:00 [pubmed] PHST- 2009/03/05 09:00 [medline] PHST- 2005/11/23 09:00 [entrez] AID - S0892-0362(05)00128-5 [pii] AID - 10.1016/j.ntt.2005.08.001 [doi] PST - ppublish SO - Neurotoxicol Teratol. 2005 Nov-Dec;27(6):781-96. doi: 10.1016/j.ntt.2005.08.001.