Demographic, health, lifestyle, and blood vitamin determinants of serum total homocysteine concentrations in the third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: Elevated serum total homocysteine (tHcy) is an independent risk factor for vascular diseases.
OBJECTIVE: Associations between serum tHcy and demographics, health and lifestyle factors, and blood vitamin concentrations were investigated.
DESIGN: Data from the third National Health and Nutrition Examination Survey, 1988-1994 were used to examine associations in men (n = 2965) and women (n = 3580) between tHcy and age, sex, race-ethnicity, body mass index, systolic and diastolic blood pressures, alcohol consumption, supplement use, red blood cell (RBC) folate, and serum creatinine, folate, vitamin B-12, and cotinine (a measure of cigarette smoking).
RESULTS: The unadjusted mean tHcy was 21.5% ( approximately 1.9 micro mol/L) higher in men than in women, 11.8% ( approximately 1.1 micro mol/L) higher in non-Hispanic whites than in Mexican Americans, 42% ( approximately 3.7 micro mol/L) higher in persons aged > or = 70 y than in persons aged < 30 y, and 10.9% ( approximately 1.0 micro mol/L) higher in supplement nonusers than in supplement users. The tHcy concentration was negatively associated with serum folate (P < 0.0001 for trend), RBC folate (P < 0.0001 for trend), and serum vitamin B-12 (P < 0.0036 for trend) and was positively associated with alcohol consumption (P < 0.0001 for trend), serum cotinine (P < 0.0001 for trend), and systolic blood pressure (P < 0.0001 for trend). Consumption of hard liquor (but not of beer or wine) was positively associated with tHcy concentration (P < 0.0001 for trend).
CONCLUSIONS: In this population-based study, the significant predictors of tHcy concentration were sex, age, race-ethnicity, serum creatinine, systolic blood pressure, body mass index, hard-liquor consumption, smoking, supplement use, serum folate, RBC folate, and serum vitamin B-12.