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BACKGROUND: Research using reconstructed exposure histories has suggested an association between heavy metal exposures, including lead, and Parkinson's disease (PD), but the only study that used bone lead, a biomarker of cumulative lead exposure, found a nonsignificant increase in risk of PD with increasing bone lead.
OBJECTIVES: We sought to assess the association between bone lead and PD.
METHODS: Bone lead concentrations were measured using ^sup 109^Cd excited K-shell X-ray fluorescence from 330 PD patients (216 men, 114 women) and 308 controls (172 men, 136 women) recruited from four clinics for movement disorders and general-community cohorts. Adjusted odds ratios (ORs) for PD were calculated using logistic regression.
RESULTS: The average age of cases and controls at bone lead measurement was 67 (SD = 10) and 69 (SD = 9) years of age respectively. In primaryanalyses of cases and controls recruited from the same-groups, compared with the lowest quartile of tibia lead, the OR for PD in the highest quartile was 3.21 [95;% confidence interval (CI), 1.17-8.83]. Results were similar but slightly weaker in analyses restricted to cases and controls recruited from the movement disorders clinics only (fourth-quartile OR = 2.5T; 95% CI, 1.11-5.93) or when we included controls recruited from sites that did not also contribute cases (fourth-quartile OR = 1.91; 95% CI, 1.01-3.60). We found no association with patella bone lead.
CONCLUSIONS: These findings, using an objective biological marker of cumulative lead exposure among typical PD patients seen in our movement disorders clinics, strengthen the evidence thai cumulative exposure to lead increases the risk of PD.
KEY WORDS: biomarker, bone lead, case-control study, epidemiology, humans, metals, risk factor. Environ Health Perspect 118:1609-1613(2010). doi: 10.1289/ehp. 1002339 [Online 31 August 2010]
Parkinson's disease (PD) is a complex disease for which a number of genetic and environmental risks have been identified. 1 win studies surest that environmental risk factors may be particularly imponani in patients whose illness begins after 50 years of age ( Tanner et aJ. 1999). Although much of the research into environmental contributors to PD has focused on pesticides, other toxicants have been explored as well (Elba? and Moisan 2008; Lai et al. 2002). Lead is known to disrupt dopaminergic function in experimental studies and can induce oxidative stress (Ercal et al....