Reply to Drs. John Andrew Tomenson and Clive Campbell

摘要

We thank Drs. Tomenson and Campbell for their attention to and valuable comments on our article (Wu et al., 2012) published in Neurotoxicology.Drs. Tomenson and Campbell pointed out that in the longitudinal study of Petrovitch et al. (2002), the authors made no mention of paraquat (PQ) when discussing pesticides commonly used in Hawaiian agriculture before 1965, with which we agree. This is most likely due to the fact that complete documentation of the historical use of pesticides in Hawaiian agriculture is unavailable as the authors have stated (page 1790, the second last paragraph), not that PQwas not used, as synthetic herbicides such as PQhad already been in widespread use since the early 1960s (Sneva, 1967). Moreover, Petrovitch's study is a prospective cohort study from 1965 to 1996, so the occupational exposure to herbicides including PQ during this period may also contribute to the results. In the Introduction, the authors cited reports of decreased motor activity commensurate with dopama-minergic system damage in rats given rotenone and mice given paraquat and the dithiocarbamate fungicide maneb in combination, in support of a possible role for agricultural chemicals in the cause of PD. More importantly, their study concluded that exposure to pesticides increases the risk of PD (Petrovitch et al., 2002), which was supported by other more recent epidemiological studies (Costello et al., 2009; Kamel et al., 2007). Therefore, in general, we believe that exposure to PQ is associated with an increased risk of PD.