Parkinson’s More Common in States With More Lead Pipes, Study Finds
In the United States, the prevalence of Parkinson’s disease is higher in states with more lead pipes that carry water to households, according to a new study.
The results add to a growing body of evidence that exposure to lead could increase the risk of developing Parkinson’s.
The study, “Lead service lines and Parkinson’s disease prevalence in U.S. States,” was published in Clinical Parkinsonism & Related Disorders.
It’s not known exactly what causes Parkinson’s disease to develop. Exposures to environmental toxins like lead may contribute, but the exact role of specific toxins is still largely unclear.
Here, a pair of scientists at the University of North Dakota conducted statistical analyses that looked at the state-by-state prevalence of Parkinson’s disease and checked for a relationship with the commonality of lead service lines (LSLs). These pipes, which transport water from municipal sources to homes, are the major source of lead in drinking water.
Results showed that, after adjusting for age, sex, and race, the number of LSLs correlated with Parkinson’s prevalence — in other words, states with more LSLs tended also to have more people with Parkinson’s disease.
More acid rain also was also associated with higher rates of Parkinson’s, which the researchers said could be because acid rain can dissolve lead from pipes and other structures into the water supply, which people then drink. The association between LSLs and Parkinson’s prevalence was still statistically significant after adjusting for acid rain.
“Our analyses showed that age-, race- and sex-adjusted prevalence rates for PD [Parkinson’s disease] are significantly correlated with the number of LSLs per state. This finding remained significant after adjustment for other risk factors, including acid rain,” the researchers concluded.
Since LSLs are a major source of lead, these findings are broadly in line with prior research that has suggested a link between lead exposure and Parkinson’s risk.
Nonetheless, the researchers noted that these results “require cautious interpretation,” since this study looked at broad statewide trends based on disease prevalence and infrastructure. The team noted that further studies that more specifically look at the association between Parkinson’s and lead exposure in individuals or households could help to further clarify these associations.