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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #137287
Title: ELEVATED METHYLMALOIC ACID CONCENTRATIONS ARE COMMON AMONG ELDERLY AMERICANS

Author
item MORRIS, MARTHA - HNRCA
item JACQUES, PAUL - HNRCA
item ROSENBERG, IRWIN - HNRCA
item SELHUB, JACOB - HNRCA

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2002
Publication Date: 7/1/2002
Citation: MORRIS, M.S., JACQUES, P.F., ROSENBERG, I.H., SELHUB, J. ELEVATED METHYLMALOIC ACID CONCENTRATIONS ARE COMMON AMONG ELDERLY AMERICANS. JOURNAL OF NUTRITION. 2002. 132:2799-2803.

Interpretive Summary: Elderly people are thought to be prone to low vitamin B-12 status; however, elderly people with low vitamin B-12 status often appear normal according to traditional tests. The serum methylmalonic acid concentration has recently come to be recognized as a metabolic indicator of vitamin B-12 status. Though several previous studies have attempted to determine the prevalence of elevated serum methylmalonic acid concentrations in various populations, no study has been capable of thus characterizing elderly Americans in all of their ethnic diversity. We used data collected in the third National Health and Nutrition Examination Survey to generate the best currently available estimate. Findings resembled those of previous studies and showed that 15 percent of elderly Americans with both apparently normal kidney function and serum vitamin B-12 levels within the normal range had serum methylmalonic acid concentrations that were elevated in comparison to those of adults aged 30-39 years. This study suggests that low vitamin B-12 status affects many elderly Americans, and that traditional tests for vitamin B-12 deficiency will miss many cases.

Technical Abstract: To describe serum methylmalonic acid (MMA) concentrations of elderly Americans and examine relations between serum MMA and other factors, we used surplus sera collected from elderly (n=1,145) and young-adult (n=1,026) participants in Phase 2 of the third National Health and Nutrition Examination Survey (1991-1994). In about 20% of participants aged >/= 65 y, serum MMA was >370 nmol/L, the 90th percentile of the distribution of participants aged 30-39 y. Consistent with previous reports, we observed strong, independent positive associations between serum MMA concentration and serum concentrations of creatinine and homocysteine. After controlling for demographic factors and creatinine, geometric mean MMA concentration was lower in non-Hispanic blacks (223.6 nmol/L; 95% confidence interval [CI], 198.8-251.5) than non-Hispanic whites (265.1 nmol/L; 95% CI, 240.3-292.4). However, the prevalence of elevated levels did not vary with race/ethnicity. Serum MMA concentration bore a strong inverse relation to serum vitamin B-12 concentration. Nevertheless, elevated serum MMA concentrations affected about 15 percent of those with both normal serum creatinine concentrations and serum B-12 concentrations >148 pmol/L. We conclude that many elderly Americans show metabolic evidence of low B-12 status, that elevations occur frequently in the absence of traditional deficiency indicators, and that levels vary with race/ethnicity and renal function.