Table 2.

Pearson and Spearman Correlations between Toenail Metal Levels at Baseline Data Collection

i. Pearson Correlation Coefficients Prob > ∣r∣ under H0: Rho=0
	Ni	Pb	Cd	Mn	As
Ni	1	0.33	0.43	0.19	0.26
		0.10	0.03*	0.36	0.21
Pb		1	0.47	0.28	0.27
			0.02*	0.17	0.20
Cd			1	0.52	0.25
				0.01*	0.23
Mn				1	0.27
					0.19
As					1
ii. Spearman Correlation Coefficients Prob > ∣r∣ under H0: Rho=0
	Ni	Pb	Cd	Mn	As
Ni	1	0.29	0.17	0.34	0.29
		0.16	0.43	0.10	0.16
Pb		1	0.50	0.42	0.39
			0.01*	0.04*	0.06
Cd			1	0.58	0.31
				<0.01*	0.13
Mn				1	0.32
					0.12
As					1

^‡Toenail metal levels were log-transformed to obtain normal distributions

^*p-values ≤ 0.05 were considered statistically significant