Choline is involved in the synthesis of
phospholipids, including blood
lipids, and is the immediate precursor of
betaine, which serves as a methyl group donor in a reaction converting
homocysteine to
methionine. Several cardiovascular risk factors are associated with plasma
homocysteine, whereas little is known about their relationship to
choline and
betaine. We examined the relation of plasma
choline and
betaine to smoking, physical activity, BMI, percent body fat, waist circumference, blood pressure, serum
lipids, and
glucose in a population-based study of 7074 men and women aged 47-49 and 71-74 y. Overall plasma concentrations (means +/- SD) were 9.9 +/- 2.3 micromol/L for
choline and 39.5 +/- 12.5 micromol/L for
betaine.
Choline and
betaine were lower in women than in men and in younger subjects compared with older (P < 0.0001). Multivariate analyses showed that
choline was positively associated with serum
triglycerides,
glucose, BMI, percent body fat, waist circumference (P < 0.0001 for all), and physical activity (P < 0.05) and inversely related to
HDL cholesterol (P < 0.05) and smoking (P < 0.0001).
Betaine was inversely associated with serum non-
HDL cholesterol,
triglycerides, BMI, percent body fat, waist circumference, systolic and diastolic blood pressure (P < 0.0001 for all), and smoking (P < 0.05) and positively associated with
HDL cholesterol (P < 0.01) and physical activity (P < 0.0001). Thus, an unfavorable cardiovascular risk factor profile was associated with high
choline and low
betaine concentrations.
Choline and
betaine were associated in opposite directions with key components of
metabolic syndrome, suggesting a disruption of mitochondrial
choline dehydrogenase pathway.