Table 3. Cross-Correlation Coefficients for Vitamin B₁₂, RBC Folate, and Sulfur Amino Acids^a,b.

Variable	Folate	Vitamin B12	Holotranscobalamin	Homocysteine	Methionine	Cystathionine	Cysteine	Glutathione	Methionine to Homocysteine Status	Supplements
RBC folate	NA	0.273c	0.293c	−0.465c	−0.002	−0.219c	−0.23	0.053c	0.361c	0.195c
Vitamin B12	0.273c	NA	0.724c	−0.304c	0.053c	−0.030	0.051d	−0.004	0.266c	0.294c
Holotranscobalamin	0.293c	0.724c	NA	−0.322c	0.072c	−0.035e	0.107c	0.014	0.291c	0.326c
Homocysteine	−0.465c	−0.304c	−0.322c	NA	−0.038e	0.406c	0.485c	−0.014	−0.792c	−0.126c
Methionine	−0.002	0.053c	0.072c	−0.038e	NA	0.228c	−0.044d	−0.024	0.592c	0.000
Cystathionine	−0.219c	−0.030	−0.035e	0.406c	0.228c	NA	0.311c	−0.102c	−0.181c	−0.028
Cysteine	−0.023	0.051d	0.107c	0.485c	−0.044d	0.311c	NA	−0.065c	−0.002	−0.026
Glutathione	0.053c	−0.004	0.014	−0.014	−0.024	−0.102c	−0.065c	NA	−0.002	−0.026
Methionine to homocysteine ratio	0.361c	0.266c	0.291c	−0.792c	0.592c	−0.181c	−0.405c	−0.002	NA	0.096c
Supplements	0.195c	0.294c	0.326c	−0.126c	0.000	−0.028	0.100c	−0.026	0.096c	NA

Abbreviations: NA, not applicable; RBC, red blood cell.

^aSpearman rank-order correlations were used.

^bDetermination of RBC folate values was routinely performed for all participants (available in 2570 individuals), but the additional markers were not routinely tested. Thus, values for other vitamins and sulfur amino acids reflect those of the 2355 participants clinically evaluated with available blood for further analyses.

^cP < .01.

^dP < .05.

^eP < .10.