The meta-analysis of eligible studies, including 1154 PD patients and 994 controls, showed a non-significant increase in serum/plasma manganese in PD patients, which was marginally significant in the common effects model ( p = 0.0333) ( Figure 7 b). 3.4.4.
The pooled data showed a significant trend towards increased zinc concentrations in whole blood from PD ( Figure 6 c). 3.3.5.
Globally, these results could suggest a possible role of global ceruloplasmin (with copper near statistical significance) and zinc deficiency in the risk for PD (perhaps related to the role of these metals in oxidative stress), despite a previous meta-analysis not showing a lower dietary intake of copper and zinc in PD patients [ 124 ].