Table 1. Plasma trace elements concentration (µg/L) in PD patients and controls.

Category	Element	Controls			Patients			p value	Reference value
		mean±SD	n	age (mean±SD)	mean±SD	n	age (mean±SD)		mean±SD
Total 1	Se*	105±33	302	65.6±12.2	115±37	238	66.6±11.3	0.005	111±22 [33]
	Cu*	1098±292			1014±274			0.001	1030±220 [26]
	Fe*	1470±648			1656±749			0.006	1440±770 [26]
	Zn*	1293±385			923±338			<0.001	1250±280 [34]
Male 2	Se*	100±31	153	67.0±12.1	111±34	121	67.1±11.3	0.009
	Cu*	1061±300			981±277			0.012
	Fe*	1503±611			1736±814			0.016
	Zn*	1289±375			921±341			<0.001
Female 2	Se	111±34	149	64.2±12.2	119±40	117	66.1±11.4	0.095
	Cu*	1137±280			1049±267			0.017
	Fe	1437±678			1574±661			0.077
	Zn*	1298±396			924±337			<0.001
Tremor-dominant 3	Se				118±32	12	67.4±11.0	0.144
	Cu				1083±219			0.771
	Fe				1541±722			0.771
	Zn*				929±419			0.004
Akinetic-rigid 3	Se				113±37	110	65.8±12.1	0.124
	Cu*				985±268			0.001
	Fe #				1524±726			0.713
	Zn*				865±281			<0.001
Mixed type 3	Se*				117±38	116	67.3±10.5	0.010
	Cu*				1034±282			0.049
	Fe* #				1794±754			<0.001
	Zn*				976±371			<0.001

^* p <0.05 vs. their respective control subjects; PD, Parkinson’s disease.

^# p =0.057 between PD patients of akinetic-rigid and mixed type.

¹ Compared between total patients and total controls.

² Compared between patients and controls within the same gender.

³ Compared between clinical subtypes of PD patients and total controls.