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. Associations of tHcy with risk factors for cervical intraepithelial neoplasia and 24-h intakes and biochemical indices of nutrients were examined. Plasma and red 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, respectively). A stepwise regression model that included red blood cell folate, plasma copper, grade of dysplasia, ethnicity, intake of polyunsaturated fatty acids, plasma vitamin B(12), intake of fat, and oral contraceptive use explained 29% of the variation in tHcy. Two hundred thirty-five subjects with cervical 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-supplemented group (7.2 +/- 1.8, 7.0 +/- 1.9, and 7.0 +/- 2.3 micromol/L, respectively) 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 micromol/L, respectively). Supplementation lowered tHcy even in subjects in the highest quintile of baseline folate. Folate, vitamin B(12), copper, and severity of dysplasia are associated with tHcy. Folate supplementation significantly lowers tHcy even in folate-replete subjects.

Effect of total plasma homocysteine on cervical dysplasia risk.

We investigated whether total plasma homocysteine (tHcy) is associated with risk for cervical intraepithelial neoplasia (CIN). tHcy was evaluated, along with numerous risk factors for CIN and biochemical indexes of nutrients, in a previously reported study population of 294 subjects with CIN and 170 female controls without CIN. tHcy was significantly higher in cases than in controls (9.1 vs. 8.3 mumol/l, p = 0.002). Human papillomavirus type 16 infection [odds ratio (OR) = 6.7], oral contraceptive use (OR = 6.0), parity (OR = 2.2), and cigarette smoking (OR = 1.9) were significantly associated with CIN after adjustment for each other and for age, number of sexual partners, and plasma tHcy, folate, iron, and zinc. Human papillomavirus type 16 positivity increased risk for CIN more when tHcy was > 9.12 mumol/l (OR = 4.7) than when it was < or = 9.12 mumol/l (OR = 3.0). Cigarette use increased risk for CIN when tHcy was > 9.12 mumol/l (OR = 3.9), but not when tHcy was < or = 9.12 mumol/l (OR = 1.5). Parity increased risk for CIN more when tHcy was > 9.12 mumol/l (OR = 4.0) than when tHcy was < or = 9.12 mumol/l (OR = 2.0). These results suggest that elevated plasma tHcy is a risk factor for cervical dysplasia and that it enhances the effects of other risk factors. It is unknown whether tHcy is serving as a marker of folate deficiency or is acting through other mechanisms.

Folic acid and the prevention of birth defects.

Thirty years ago, it was suggested that maternal intake of certain vitamins during pregnancy affected the incidence of serious fetal malformations. Subsequent research has revealed that folate (folic acid), a B vitamin, plays a crucial role in the development of the central nervous system during the early weeks of gestation, which is generally before the pregnancy is confirmed. In a significant number of embryos, an inadequate supply of folate at this time leads to a failure of the primitive neural tube to close and differentiate normally and results in neural tube birth defects (NTD). Numerous studies have confirmed the importance of an adequate intake of folate during the weeks just before and after conception. Overall, the data predict that if women consume multivitamin supplements containing folic acid during the periconceptional period, the number of children born with serious malformations (such as spina bifida and anencephaly) could be reduced by half. Although programs to increase dietary folate intake of potential mothers may be effective in reducing NTD, the only proven and practical preventive measure currently available is to take oral multivitamin supplements containing folic acid. Multivitamin supplementation has also been associated with reduced incidence of other congenital malformations. Current research is focusing on the role of micronutrients in embryogenesis, and on methods to identify prospective mothers at increased risk for bearing a child with NTD or with other major malformations shown to occur at reduced frequency with multivitamin supplementation. Of equal importance is the development of methods to communicate current knowledge as a public health measure.

A longitudinal analysis of human papillomavirus 16 infection, nutritional status, and cervical dysplasia progression.

To evaluate the effect of potential risk factors, especially human papillomavirus type 16 (HPV-16) infection and nutritional status on the course of cervical dysplasia, we analyzed data from an intervention trial conducted from 1985 to 1990, in Birmingham, Alabama. With the use of data of four repeated evaluations of dysplasia at an interval of 2 months, specific relationships between HPV-16 infection, plasma retinol and zinc levels, and dysplasia progression were evaluated through longitudinal data analysis of generalized estimating equations. Repeated assessments of nutritional status from blood samples, HPV-16 infection, and dysplasia diagnosis were available from 206 women. Dysplasia diagnosis was confirmed by both Papanicolaou smear and colposcopy examinations and was classified as normal, low, or high grade squamous intraepithelial lesions according to the Bethesda system and assigned a score of 0, 1, or 2, respectively. Generalized estimating equation analyses were performed with assumptions of variance of Poisson and link of logarithm. Separate analyses were also conducted for HPV-16-positive and HPV-16-negative women. By multivariate modeling with adjustment for age, race, smoking, oral contraceptive use, and plasma levels of nutrients, HPV-16 infection was found to be related to the progression of cervical dysplasia, with a relative risk of 1.19 and a 95% confidence interval of 1.03-1.38. High plasma levels of retinol were related to the regression of cervical dysplasia, especially in HPV-16-positive women. A protective effect was also observed for high levels of zinc.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary folate requirement determined for channel catfish, Ictalurus punctatus.

Juvenile channel catfish, Ictalurus punctatus, were fed semipurified basal diets containing 0, 0.2, 0.5, 1.0, 4.0 or 10.0 mg/kg of folic acid or 10 g/kg of succinylsulfathiazole in aquaria for 15 wk. Fish fed the sulfonamide showed higher mortality, lower weight gain, lower thrombocyte counts, higher hemocytoblast and neutrophil counts, and lower liver folate concentrations than did control fish (0 folic acid), indicating that significant intestinal bacterial synthesis of folate occurs in channel catfish. There were positive quadratic regressions of weight gain, hematocrit, erythrocyte and leukocyte numbers, and positive linear regressions of plasma and liver folate on dietary folic acid concentrations. Broken-line analysis showed that the dietary requirements for folic acid for optimum weight gain, hematocrit, and erythrocyte and leukocyte numbers were 1.01, 1.17, 1.12 and 1.15 mg/kg, respectively. Plasma and liver concentrations of folate associated with normal growth and hematopoiesis were 22.9 nmol/L and 20.0 nmol/g, respectively. Ratios of leukocytes and lymphocytes to erythrocytes were maximal in fish fed 4.0 mg folic acid/kg, indicating that immunocompetence may increase as the dietary dose exceeds that required for normal growth. Anemia in folate-deficient channel catfish was characterized by pale livers, spleens, gills and kidneys, and by poikilocytosis, anisocytosis, pyknosis, cytoplasmic clearing, increased numbers of hemocytoblasts, macrocytosis, and binucleated erythrocytes or "spectacle" cells.

A case control study of nutritional factors and cervical dysplasia.

The association of nutritional factors with cervical dysplasia was examined through a case-control study. Analysis was conducted in 257 cases and 133 controls confirmed both by cytological examination and colposcopic findings. A 24-h dietary recall questionnaire was used to assess nutritional intake. Various risk factors (including age at first intercourse, number of sexual partners, parity, cigarette smoking, oral contraceptive use, human papillomavirus type 16 infection, and age and race) were adjusted for their potential confounding effects. While analyses were also performed to adjust for total calories, results were not changed significantly. Among the nutrients examined, vitamin A intake showed a significantly increased risk at the lowest quartile compared to the highest quartile, with an odds ratio of 2.2 (95% confidence interval, 1.2-4.2). A significant trend of increasing risk was also observed with lower intake of vitamin A (P = 0.05). Riboflavin showed increased risk at the two lower quartiles of intake with a trend test P value of 0.04. Increased risk was also found for lower intakes of vitamin C compared to the highest intake level. For folate, increased risk was found in the second highest quartile compared with the highest quartile with an odds ratio of 2.0 (95% confidence interval, 1.0-3.8). The calcium:phosphorus ratio showed an increased risk at the lowest level (odds ratio, 2.0; 95% confidence interval, 1.0-4.3). Insufficient intake of vitamin A, riboflavin, ascorbate, and folate is associated with an increased risk of cervical dysplasia.

Folate status, women's health, pregnancy outcome, and cancer.

Key observations by Dr. Lucy Wills 65 years ago have led to the identification of folate as a nutrient essential for the prevention of megaloblastic anemia of pregnancy. The more recently discovered relationships of folate status to cervical dysplasia, neural tube defects, and atherosclerosis are reviewed here.

Evaluation of three nutritional assessment methods in a group of women.

We conducted a reproducibility study of four 24-hour dietary recalls (N = 224) and four biochemical assessments of nutritional status (N = 265) in a group of women in Alabama. For 24-hour recalls, the variance component ratios were all greater than 1, and the intraclass correlation coefficients ranged from 0.16 to 0.27 for macronutrients, and from 0.09 to 0.37 for vitamins and minerals. The intraclass correlation coefficients for biochemical assessments ranged between 0.39 and 0.74 with corresponding variance component ratios of 1 or below for most nutrients. The correlation coefficients between the food frequency questionnaire on the usual dietary intake during the year preceding the beginning of study and the mean values of four 24-hour dietary recalls administered at the initial visit and again after 2, 4, and 6 months ranged from 0.3 to 0.4 for most nutrients. We found plasma beta-carotene levels to be moderately correlated with dietary vitamin A (r = 0.20) and beta-carotene (r = 0.22).

Effect of folate on cervical cancer. Synergism among risk factors.

Folate deficiency appears to play a crucial role early in cervical carcinogenesis by facilitating the incorporation of HPV genomes at a fragile chromosomal site. Thereafter, multiple nutritional, hormonal, and immunologic factors probably interact in a synergistic manner to determine whether the cell line becomes immortalized and invasive.

Plasma and urinary levels of biopterin, neopterin, and related pterins and plasma levels of folate in infantile autism.

Tetrahydrobiopterin is essential for brain cells to make monoamine neurotransmitters. It has been reported that the concentrations of tetrahydrobiopterin in plasma and urine are low in certain mental disorders and that oral supplements are beneficial. A group of Japanese investigators have been conducting clinical trials of the effect of administration of tetrahydrobiopterin to autistic children and reported that it is beneficial with no significant side effects. We, therefore, initiated a study to assess plasma and urinary levels of tetrahydrobiopterin in infantile autism to see if they are reduced. Besides tetrahydrobiopterin, we also determined plasma and urinary levels of neopterin and monapterin in these individuals in order to evaluate the status of dihydroneopterin triphosphate, a key biosynthetic precursor of tetrahydrobiopterin. Sixteen autistic children and 12 healthy controls were included in this study. Results indicated that the plasma and urinary levels of tetrahydrobiopterin are not statistically different between the two groups and, therefore, no simple explanation for the beneficial effects of administration of tetrahydrobiopterin on autistic children can be offered at the present time. In contrast, plasma and urinary levels of neopterin were depressed (.01 less than p less than .05) and plasma monapterin was also significantly depressed (p less than .01) in autistic subjects compared with controls. Levels of other pterins, including folate, were not statistically different between the two groups. The basis for this depression in neopterin and monapterin is unknown. It does not seem likely that this depression could be attributed to a difference in age or T-lymphocyte/macrophage activity. However, further studies are needed to investigate these possibilities.

Oral folic acid supplementation for cervical dysplasia: a clinical intervention trial.

OBJECTIVE: We attempted to evaluate the effect of oral folic acid supplementation on the course of cervical dysplasia. STUDY DESIGN: A total of 235 subjects with grade 1 or 2 cervical intraepithelial neoplasia were randomly assigned to receive either 10 mg of folic acid or a placebo daily for 6 months. Clinical status, human papillomavirus type 16 infection, and blood folate levels were monitored at 2-month intervals. Outcome data were subjected to chi 2 analysis. RESULTS: The prevalence of human papillomavirus type 16 infection initially was 16% among subjects in the upper tertile of red blood cell folate versus 37% in the lower tertile (trend p = 0.035). After 6 months no significant differences were observed between supplemented and unsupplemented subjects regarding dysplasia status, biopsy results, or prevalence of human papillomavirus type 16 infection. CONCLUSION: Folate deficiency may be involved as a cocarcinogen during the initiation of cervical dysplasia, but folic acid supplements do not alter the course of established disease.

Folate deficiency and cervical dysplasia.

OBJECTIVE: To test the hypothesis that nutritional deficiency affects the incidence of cervical dysplasia in young women. DESIGN AND SETTING: Case-control study. Participants were derived from community family-planning clinics and referrals to a colposcopy center. PARTICIPANTS: A total of 726 subjects were screened, yielding 294 cases of dysplasia and 170 controls defined by coexistent cytologic and colposcopic evidence. MAIN OUTCOME MEASURES: Planned prior to data collection. Odds ratios were computed using logistic regression models to evaluate association between cervical dysplasia and sociodemographic, sexual, and reproductive factors; smoking; oral contraceptive use; human papillomavirus (HPV) infection; and 12 nutritional indices determined by blind analysis of nonfasting blood specimens. RESULTS: The number of sexual partners, parity, oral contraceptive use, and HPV-16 infection were significantly associated with cervical dysplasia. Plasma nutrient levels were generally not associated with risk. However, red blood cell folate levels at or below 660 nmol/L interacted with HPV-16 infection. The adjusted odds ratio for HPV-16 was 1.1 among women with folate levels above 660 nmol/L but 5.1 (95% confidence interval, 2.3 to 11) among women with lower levels. Interactions of red blood cell folate levels with cigarette smoking and parity were also present but were not statistically significant. CONCLUSION: Low red blood cell folate levels enhance the effect of other risk factors for cervical dysplasia and, in particular, that of HPV-16 infection.

Human papillomavirus screening for women with atypical Papanicolaou smears.

A study was undertaken to evaluate the utility of human papillomavirus (HPV) DNA screening and colposcopy in the management of women whose Papanicolaou smears demonstrated atypia less than dysplasia. Fifty patients whose initial Papanicolaou smears were interpreted as showing atypia less than dysplasia were evaluated for the presence of HPV 16 DNA in exfoliated cervicovaginal cells and for histologic findings on biopsy. Those 50 patients were compared to two groups of patients: one consisting of 124 patients with biopsy-documented cervical intraepithelial neoplasia (CIN) and another of 112 patients with normal Papanicolaou smears. The presence of HPV 16 DNA was confirmed with Southern analysis in 46% of patients with atypical Papanicolaou smears, 46% with confirmed CIN and 11.6% with normal Papanicolaou smears. The 50 patients with atypical smears underwent colposcopically directed cervical biopsies, revealing the following results: 14 (28%) had normal histology, 29 (58%) had koilocytosis without dysplasia, and 7 (14%) had CIN. HPV 16 DNA was present in exfoliated cervicovaginal cells from a large percentage of patients from each category (50% of patients with normal histology, 41.2% with koilocytosis and 57% with CIN). HPV 16 DNA screening did not predict which patients with atypical smears had underlying CIN. Colposcopically directed biopsy remains the evaluation method of choice.

Evaluation of the deoxyuridine suppression test by using whole blood samples from folic acid-supplemented subjects.

We performed the deoxyuridine suppression test (dUST) along with assessment of folate and vitamin B-12 status in blood specimens from 136 normal women and 109 women with cervical dysplasia. All tests were repeated at 2, 4, and 6 mo in subjects with dysplasia during a randomized, double-blind intervention trial in which 50 received a 10-mg daily oral folic acid supplement (F group) and 59 received a placebo (P group). Median folate concentration increased fivefold in plasma and threefold in erythrocytes of F group beginning at the second months and remained elevated whereas concentrations of the P group remained unchanged. Vitamin B-12 values did not vary significantly in either group. The dUST value decreased from 10.4 +/- 4.6% (means +/- SD) pretreatment to 4.5 +/- 4.7% in F group after 2 mo (p less than 0.001). The dUST values had significant negative correlation with plasma and erythrocyte folate concentrations. However, erythrocyte folate had the greatest power to distinguish P group from F group.

Folic acid safety and toxicity: a brief review.

Oral folic acid (pteroylglutamic acid) is generally regarded as not toxic for normal humans but it may cause neurological injury when given to patients with undiagnosed pernicious anemia. The vitamin should be given with caution to drug-treated epileptic patients because seizure control may be affected. Some studies suggest that folic acid supplements interfere with intestinal zinc absorption in humans and animals but others do not confirm such an effect. The weight of current evidence favors the view that daily supplements of 5-15 mg folic acid do not have significant adverse effects on Zn nutriture in healthy nonpregnant subjects. Because antifolate medications are now being used to treat a wide range of malignant and nonmalignant disorders, further investigation is needed concerning folate metabolism and the safety of supplements in patients with these disorders.

Zinc concentration in plasma and erythrocytes of subjects receiving folic acid supplementation.

It has been suggested that oral supplements of folic acid interfere with the intestinal absorption of zinc and may have toxic side effects. The concentrations of Zn and folate in blood were monitored in a group of women with cervical dysplasia randomly assigned to receive 10 mg/d of either folic acid (pteroylglutamic acid) or ascorbate. Fifty subjects were evaluated after 2 mo; 21 of the same subjects were evaluated again after 4 mo. No untoward clinical effects were observed. Significant elevation of erythrocyte folate above the baseline value was observed in the supplemented group but not in the placebo group (p less than 0.001). The concentration of Zn in plasma and erythrocytes did not change significantly in either the folate-treated or placebo groups after 2 and 4 mo. It is concluded that carefully controlled clinical intervention trials of this type do not impose a risk of depleting the concentration of Zn in erythrocytes and plasma.

Improvement in bronchial squamous metaplasia in smokers treated with folate and vitamin B12. Report of a preliminary randomized, double-blind intervention trial.

To test whether changes in folate and vitamin B12 nutrition modify the severity of potentially premalignant lesions identified by cytology in sputum samples of smokers, we conducted a randomized, controlled prospective intervention trial in smokers with bronchial squamous metaplasia. Seventy-three men with a history of 20 or more pack-years of cigarette smoking who had metaplasia on one or more sputum samples were stratified according to smoking level and randomly assigned to four months' treatment with either placebo or 10 mg of folate plus 500 micrograms of hydroxocobalamin. Direct cytological comparison of the two groups after four months showed significantly greater reduction of atypia in the supplemented group. This provides preliminary evidence that atypical bronchial squamous metaplasia may be reduced by supplementation with folate and vitamin B12. However, the significance of these findings is tempered by substantial spontaneous variation in sputum cytologies, the small study population, the short duration of the trial, and the supraphysiological doses of folate and B12 used. The results should not be construed as pointing to a potential way of preventing lung cancer in individuals who continue to smoke or as supporting self-medication with large doses of folate or B12 by smokers.

Folate conjugase activity in the plasma and tumors of breast-cancer patients.

The activity of folate conjugase (pteroylpolyglutamate hydrolase, EC 3.4.22.12) was measured in plasma from normal subjects and patients with breast cancer using pteroylglutamyl-gamma-glutamyl-gamma-(U14C) glutamate as the substrate. Conjugase assays also were performed on samples of breast-tumor tissue, normal breast, and fibroadenoma. When assayed at pH 4.5 and 7.4, mean plasma conjugase activity was significantly (p less than 0.05) elevated in a group of patients with anatomically proven metastatic disease (n = 21) when compared with control subjects (n = 12) and a group of patients (n = 13) with no clinical evidence of disease after mastectomies. Mean plasma conjugase activity assayed at pH 4.5 also was significantly higher in the metastatic disease group when compared with breast cancer patients before mastectomy (n = 9) and fibroadenoma patients before biopsy (n = 3). The specific activity of tissue conjugase assayed at pH 4.5 was significantly higher (p less than or equal to 0.05) in infiltrating ductal carcinoma than in normal adjacent breast tissue according to the Wilcoxon test for paired samples (n = 10).