Coffee Consumption and Cystatin-C-Based Estimated Glomerular Filtration Rates in Healthy Young Adults: Results of a Clinical Trial

Table 4

Correlation coefficients between changes in cystatin-C-based eGFR (determined using five different equations) and changes in serum magnesium between the start and end of each consumption period.

Cystatin C-based eGFR	Coffee		Green tea
	r	P value	r	P value
Tan et al.	0.47	.04	0.08	.75
Grubb et al.	0.48	.04	0.10	.68
Sjöström et al.	0.47	.04	0.08	.75
Larsson et al.	0.49	.03	0.09	.75
Hoek et al.	0.47	.04	0.08	.75

Correlation coefficients were examined by the Pearson correlation tests.