Table 3.

Category definitions and sample sizes^*

Serum folate, nmol/L	NHANES III†						NHANES 1999–2002
	Hcy			MMA			Hcy/MMA
	<9.1	9.1–13.5	≥13.6	≤9.7	9.7–13.5	≥13.6	<19.3	19.3–25.9	26–32.5	≥32.6
Serum B12 ≥ 148 pmol/L, n	1,581	1,271	1,970	501	309	655	1,032	1,152	892	2,267
Serum B12 < 148 pmol/L, n	39	41	37	15	13	16	32	33	32	33

*Sample sizes given are after exclusions and for subjects with complete information for multivariate modeling.

^†In the NHANES III, Hcy and MMA were measured in surplus serum collected in the last 3 years of the 6-year survey, and MMA was measured in surplus serum samples measured from subjects ≥65 years old and from a sample of subjects 30–39 years old.