Correlates of total plasma homocysteine: Folic acid, copper, and cervical dysplasia

We examined correlates of total plasma homocysteine (tHcy) in 294 subjects with cervical intraepithelial neoplasia and 170 control subjects. Associati ons of tHcy with risk factors for cervical intraepithelial neoplasia and 24 -h intakes and biochemical indices of nutrients were examined. Plasma and r ed blood cell folate and plasma B-12 were strong inverse correlates of tHcy (r = -0.35, -0.31, and -0.27, respectively). Plasma copper and severity of dysplasia were positively correlated with tHcy (r = 0.14 and 0.21, respect ively). A stepwise regression model that included red blood cell folate, pl asma copper, grade of dysplasia, ethnicity, intake of polyunsaturated fatty acids, plasma vitamin B-12, intake of fat, and oral contraceptive use expl ained 29% of the variation in tHcy. Two hundred thirty-five subjects with c ervical intraepithelial neoplasia were randomized to receive folic acid (10 mg/d) or placebo for 6 mo. After 2, 4, and 6 mo, mean tHcy in the folate-s upplemented group (7.2 +/- 1.8, 7.0 +/- 1.9, and 7.0 +/- 2.3 mu mol/L, resp ectively) was significantly lower than baseline and the placebo group at 2, 4, and 6 mo (8.9 +/- 3.1, 8.4 +/- 3.0, and 8.9 +/- 3.1 mu mol/L, respectiv ely). Supplementation lowered tHcy even in subjects in the highest quintile of baseline folate. Folate, vitamin B-12, copper, and severity of dysplasi a are associated with tHcy. Folate supplementation significantly lowers tHc y even in folate-replete subjects. Nutrition 2000;16:411-316. (C)Elsevier S cience Inc. 2000.