Low serum and red blood cell folate are moderately, but nonsignificantly associated with increased risk of invasive cervical cancer in U.S. women

Negative associations between folate and bacterial vaginosis in the NHANES 2001 to 2004

BACKGROUND

Bacterial vaginosis (BV) is one of the most common infections among women of reproductive age and accounts for 15-50% of infections globally. The role played by folate in the pathogenesis and progression of BV is poorly understood. The aim of this study was to investigate the association between serum folate, red blood cell (RBC) folate, and BV in American women.

METHODS

1,954 participants from the 2001-2004 National Health and Nutrition Examination Survey (NHANES) program were included in this study. Multiple logistic regression was used to analyze the association between serum folate, RBC folate, and BV, and covariates including race, age, education level, and body mass index were used to construct adjusted models. Stratified analysis was used to explore the stability of the above associations in different populations.

RESULTS

In the present cross-sectional study, we found that serum folate and RBC folate were inversely associated with the risk of BV. In the fully adjusted model, the risk of BV was reduced by 35% (OR=0.65, 95% CI: 0.51~0.83, p=0.0007) in the highest serum folate group and 32% (OR=0.68, 95% CI: 0.53~0.87, p=0.0023) in the highest RBC folate group compared to the lowest group.

CONCLUSIONS

The results of this study indicated that serum folate and RBC folate were inversely associated with the risk of BV folate supplementation may play an important role in the prevention and management of BV.

Low erythrocyte folate levels and increased risk of invasive cervical cancer in Chinese women

AIM

To investigate the relationship between erythrocyte folate levels and cervical lesions.

METHODS

Using a case-control method, patients with cervical lesions from September 2021 to February 2022 in the Department of Obstetrics and Gynecology, Jiangnan University Hospital were selected as study subjects. After cervical biopsy, 40 cases of cervical intraepithelial neoplasia (CIN) CIN3 and 65 cases of cervical cancer as case group. The normal population of 120 cases attending the same period served as the control group. A competitive model was used to establish a chemiluminescence immunoassay (CLIA) for human erythrocyte folate. Erythrocyte folate levels of 225 subjects were determined.

RESULTS

Serum folate levels were 7.82 ± 3.13, 8.04 ± 3.58, and 7.58 ± 4.30 ng/ml in the control, CIN3, and cervical cancer groups, with no statistically significant differences (p = 0.959). Erythrocyte folate levels were 307.27 ± 122.95, 306.52 ± 189.77, and 285.42 ± 125.74 ng/ml, respectively, with statistically significant differences (p = 0.03).

CONCLUSIONS

In a population of middle-aged Chinese women, the lower the erythrocyte folate value, the greater the risk of cervical cancer. In addition, serum folate levels were not associated with cervical lesions.

Associations of RBC and Serum Folate Concentrations with Cervical Intraepithelial Neoplasia and High-Risk Human Papillomavirus Genotypes in Female Chinese Adults

BACKGROUND

Although folate status is associated with cervical carcinogenesis, it is not clear whether folate deficiency is associated with risk of cervical intraepithelial neoplasia (CIN) progression and infection with high-risk human-papillomavirus (hrHPV).

OBJECTIVES

To evaluate the associations of RBC and serum folate concentrations with prevalence of CIN grades and hrHPV infection, their interactions with prevalence of CIN grades, and RBC folate with the risk of CIN1 progressing to CIN2.

METHODS

Using data from the Shanxi CIN cohort of 2304 female Chinese adults, we used logistic-regression model to estimate ORs and prevalence ratios (PRs) of RBC and serum folate concentrations with prevalence of CIN grades and hrHPV infection. Categoric and spline analyses were used to evaluate the dose-response relations. We estimated the association of RBC folate with risk of CIN1 progressing to CIN2 in the nested case-control cohort.

RESULTS

An inverse association was observed between increased RBC folate concentration and the odds of all CIN grades [quartile 1 (Q1) compared with Q4: OR: 2.28; 95% CI: 1.77, 2.93; Ptrend < 0.001]. Significant interaction of RBC folate and hrHPV infection was observed for prevalence of CIN2 or above (Pinteraction < 0.01). No associations were found between RBC and serum folate with PRs of hrHPV in each CIN grade. Over a median follow-up of 21.0 mo, RBC folate was associated with increased risk of CIN1 progressing to CIN2 (Q1 compared with Q4: OR: 3.86; 95% CI: 1.01, 14.76).

CONCLUSIONS

Our study indicates that RBC folate concentration is associated with prevalence of CIN grades and CIN1 progression in female Chinese adults. Maintenance of normal folate status is important for reducing the risk of CIN and its progression in women with or without hrHPV infection.

Blood-based biomarkers of human papillomavirus-associated cancers: A systematic review and meta-analysis

BACKGROUND

Despite the significant societal burden of human papillomavirus (HPV)-associated cancers, clinical screening interventions for HPV-associated noncervical cancers are not available. Blood-based biomarkers may help close this gap in care.

METHODS

Five databases were searched, 5687 articles were identified, and 3631 unique candidate titles and abstracts were independently reviewed by 2 authors; 702 articles underwent a full-text review. Eligibility criteria included the assessment of a blood-based biomarker within a cohort or case-control study.

RESULTS

One hundred thirty-seven studies were included. Among all biomarkers assessed, HPV-16 E seropositivity and circulating HPV DNA were most significantly correlated with HPV-associated cancers in comparison with cancer-free controls. In most scenarios, HPV-16 E6 seropositivity varied nonsignificantly according to tumor type, specimen collection timing, and anatomic site (crude odds ratio [cOR] for p16+ or HPV+ oropharyngeal cancer [OPC], 133.10; 95% confidence interval [CI], 59.40-298.21; cOR for HPV-unspecified OPC, 25.41; 95% CI, 8.71-74.06; cOR for prediagnostic HPV-unspecified OPC, 59.00; 95% CI, 15.39-226.25; cOR for HPV-unspecified cervical cancer, 12.05; 95% CI, 3.23-44.97; cOR for HPV-unspecified anal cancer, 73.60; 95% CI, 19.68-275.33; cOR for HPV-unspecified penile cancer, 16.25; 95% CI, 2.83-93.48). Circulating HPV-16 DNA was a valid biomarker for cervical cancer (cOR, 15.72; 95% CI, 3.41-72.57). In 3 cervical cancer case-control studies, cases exhibited unique microRNA expression profiles in comparison with controls. Other assessed biomarker candidates were not valid.

CONCLUSIONS

HPV-16 E6 antibodies and circulating HPV-16 DNA are the most robustly analyzed and most promising blood-based biomarkers for HPV-associated cancers to date. Comparative validity analyses are warranted. Variations in tumor type-specific, high-risk HPV DNA prevalence according to anatomic site and world region highlight the need for biomarkers targeting more high-risk HPV types. Further investigation of blood-based microRNA expression profiling appears indicated.

Interactions between serum folate and human papillomavirus with cervical intraepithelial neoplasia risk in a Chinese population-based study

Background

Although folate deficiency has long been implicated in cancer development, uncertainties remain concerning its role in cervical cancer prevention. In particular, the interaction between human papillomavirus (HPV) and folate in the risk of cervical intraepithelial neoplasia (CIN) has been little studied.

Objective

The goal of this study was to evaluate the dose-response association of serum folate with the risk of CIN, and the potential for HPV to modify the risk of CIN.

Design

We performed a cross-sectional analysis of screening data in 2304 women aged 19-65 y who participated in an ongoing cohort of 40,000 women in China. Both categoric and spline analyses were used to evaluate the dose-response relation between serum folate and CIN risk.

Results

After adjusting for potential confounders, a statistically significant inverse association between serum folate concentration and at least grade 2 CIN (CIN2+) risk was observed (1st quartile compared with 4th quartile: OR = 1.40; 95% CI: 1.09, 1.79; P-trend < 0.01); however, serum folate concentration was not associated with CIN1 risk. The risk patterns are similar when limited to only CIN2 and CIN3. An inverse linear relation between increased serum folate concentration and the risk of higher-grade CIN (CIN2, CIN3, and CIN2+) was also observed (for CIN2+: P-overall < 0.01, P-nonlinearity = 0.96). The highest risk of CIN2+ was observed in women with high-risk HPV types, who also had the lowest serum folate concentrations (P-interaction < 0.01).

Conclusions

Our study indicates that serum folate is inversely associated with the risk of higher-grade CIN in Chinese women either with or without high-risk HPV infection. Thus, maintenance of normal serum folate levels may prove important for reducing the risk of CIN in women.

Association between serum folate level and cervical cancer: a meta-analysis

PURPOSE

The aim of this study was to evaluate the association between serum folate level and cervical cancer.

METHODS

PubMed, Medline, Springer, Elsevier Science Direct, Cochrane Library and Google scholar were searched for relevant trials. Rev.Man5.1 and Stata 11.0 software were applied for this meta-analysis. Odds Ratio (OR) and 95 % confidence intervals (95 % CI) were collected and calculated in a fixed-effects model or a random-effects model when appropriate. Subgroup analysis was performed by sample size, participant's geographical location and definition of deficient serum folate level.

RESULTS

A total of 6 case-control studies including 2383 participants were included in the meta-analysis. The overall meta-analysis showed that there were significant differences between cases and controls, suggesting that deficient serum folate level was associated with the increased risk of cervical cancer. After stratification subgroup analysis, significant difference was also found in subgroup with sample size <500 as well as in Asian population, but not in subgroup with sample size ≥500, American populations as well as different definition of deficient serum folate level (<6.4 ng/ml or others).

CONCLUSIONS

Based on our meta-analysis, deficiency of serum folate level was associated with the increased risk of cervical cancer among Asian populations.

Maternal micronutrient status and preterm versus term birth for black and white US women

OBJECTIVE

Micronutrient deficiencies are hypothesized to play a role in spontaneous preterm birth (PTB; <37 weeks of gestation) and possibly the racial disparity in rates of PTB between black and white women. Yet relatively few studies have addressed the role of micronutrient deficiencies in spontaneous PTB among black and white women in the United States. The purpose of this study was to investigate whether 25-hydroxy vitamin D (25-OH-D), folate, and omega-6/omega-3 fatty acid status are associated with spontaneous PTB among black and white women in the United States.

METHODS

Biospecimens and medical record data for this study were derived from a subsample of the 1547 women enrolled into the Nashville Birth Cohort during 2003-2006. We randomly selected 80 nulliparous and primiparous women for whom stored plasma samples from the delivery admission were available and analyzed the stored plasma for 25-OH-D, folate, and total omega-6/omega-3 fatty acids. We used multivariate logistic regression to assess the odds of spontaneous PTB among women with 25-OH-D <20 ng/mL, folate <5 ug/L, and omega-6/omega-3 >15.

RESULTS

An omega-6/omega-3 ratio >15 was significantly associated with spontaneous PTB for white (adjusted odds ratio [aOR] 4.25, 95% confidence interval [CI] 1.25-14.49) but not black women (aOR 1.90, 95% CI: 0.69-5.40), whereas no significant relationships were observed for folate and 25-OH-D status and PTB for black or white women.

CONCLUSION

Maternal plasma total omega-6/omega-3 fatty acid ratio >15 at delivery was significantly associated with spontaneous PTB for white, but not black, women.

Maternal vitamin D, folate, and polyunsaturated fatty acid status and bacterial vaginosis during pregnancy

OBJECTIVE

To investigate associations among serum 25-hydroxy-vitamin D (25-OH-D), folate, omega-6/omega-3 fatty acid ratio and bacterial vaginosis (BV) during pregnancy.

METHODS

Biospecimens and data were derived from a random sample (N = 160) of women from the Nashville Birth Cohort. We compared mean plasma nutrient concentrations for women with and without BV during pregnancy (based on Nugent score ≥7) and assessed the odds of BV for those with 25-OH-D <12 ng/mL, folate <5 ug/L, and omega-6/omega-3 ratio >15.

RESULTS

The mean plasma 25-OH-D was significantly lower among women with BV during pregnancy (18.00±8.14 ng/mL versus 24.34±11.97 ng/mL, P = 0.044). The adjusted odds of BV were significantly increased among pregnant women with 25-OH-D <12 ng/mL (aOR 5.11, 95% CI: 1.19-21.97) and folate <5 ug/L (aOR 7.06, 95% CI: 1.07-54.05).

CONCLUSION

Vitamin D and folate deficiencies were strongly associated with BV (Nugent score ≥7) during pregnancy.

Vitamin or antioxidant intake (or serum level) and risk of cervical neoplasm: a meta-analysis

BACKGROUND

Case-control studies have reported the preventive effect of vitamin or antioxidant intake on cervical neoplasms such as cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. However, the findings are inconsistent.

OBJECTIVE

To investigate quantitative effects of vitamin or antioxidant intake on cervical neoplasm using meta-analysis.

SEARCH STRATEGY

We searched PubMed, EMBASE and the Cochrane Library in November 2008. All articles searched were independently reviewed and selected by two evaluators according to predetermined selection criteria.

SELECTION CRITERIA

We included case-control studies reporting an association between vitamin or antioxidant intake (or serum level) and cervical neoplasm risk and reporting the adjusted odds ratios (OR) and 95% confidence intervals (CI), whenever possible.

DATA COLLECTION AND ANALYSIS

After retrieval of data from selected articles, we performed a meta-analysis using both fixed-effects and random- effects models.

MAIN RESULTS

Of 274 articles meeting our initial criteria, we included 22 case-control studies involving a total of 10,073 participants. In meta-analyses by type of vitamin or antioxidant, a significant preventive effect on cervical neoplasm was found in intakes of vitamin B12 (OR 0.35, 95% CI 0.19-0.63; n=2), vitamin C (OR 0.67, 95% CI 0.55-0.82; n=8), vitamin E (OR 0.56, 95% CI 0.35-0.88; n=10), and beta-carotene (OR 0.68, 95% CI 0.55-0.84; n=9).

AUTHORS' CONCLUSIONS

The findings of this meta-analysis indicate that overall, there were preventive effects of vitamin or antioxidant intake on cervical neoplasms in case-control studies.

Interaction among folate, riboflavin, genotype, and cancer, with reference to colorectal and cervical cancer

Epidemiological studies have linked low folate intake with an increased risk of epithelial cancers, including colorectal cancer and cervical cancer. Riboflavin has received much less attention, but there is increasing interest in the well-established role that flavins play in folate metabolism and the possible synergy of a protective effect between these 2 vitamins. Folate plays a key role in DNA synthesis, repair, and methylation, and this forms the basis of mechanistic explanations for a putative role for folate in cancer prevention. The role of folate in these processes may be modulated by genotype for the common C677T thermolabile variant of methylene tetrahydrofolate reductase (MTHFR), homozygosity for which is associated with lower enzyme activity, lower plasma and red blood cell folate, and elevated plasma homocysteine. Riboflavin, as FAD, is a cofactor for MTHFR and there is evidently some interaction among riboflavin status, folate status, and genotype in determining plasma homocysteine, a functional marker of folate status. The MTHFR C677T polymorphism appears to interact with folate and riboflavin in modulating cancer risk in a manner that varies according to cancer site. Most evidence points to a protective effect of this polymorphism for risk of colorectal cancer, but the effect on cervical cancer risk is not clear. The effect of this polymorphism on cancer risk seems to be further modulated by other factors, including alcohol and, in the case of cervical cancer, infection with the human papilloma virus. An additional factor determining the effect of diet and genotype interactions on cancer risk may be the stage of cancer development.

The role of diet and nutrition in cervical carcinogenesis: A review of recent evidence

Our objective was to provide an update on recent epidemiologic evidence about the role of diet and nutrition on the risk of human papillomavirus (HPV) persistence and cervical neoplasia, taking HPV into account. We conducted a systematic review and qualitative classification of all observational studies controlling for HPV infection published between March 1995 and November 2003 and of all randomized clinical trials published between January 1991 and November 2003. Scientific evidence was classified as convincing, probable, possible or insufficient, as used in a previous study on diet and cancer. Thirty-three studies were eligible for this review (10 clinical trials, 8 observational prospective studies and 15 case-control studies). The few studies on HPV persistence showed a possible protective effect of fruits, vegetables, vitamins C and E, beta- and alpha-carotene, lycopene, luterin/zeaxanthin and cryptoxanthin. Evidence for a protective effect of cervical neoplasia was probable for folate, retinol and vitamin E and possible for vegetables, vitamins C and B12, alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin and cryptoxanthin. Evidence for an increased risk of cervical neoplasia associated with high blood homocysteine was probable. Results did not differ between studies looking at preneoplastic and invasive lesions or between retrospective and prospective studies. The available evidence for an association between diet and nutritional status and cervical carcinogenesis taking HPV infection into account is not yet convincing. Large cohort studies are needed to adequately assess the role of foods and nutrients in cervical HPV carcinogenesis.

The effect of methylenetetrahydrofolate reductase polymorphism C677T on cervical cancer in Korean women

OBJECTIVES

Methylenetetrahydrofolate reductase (MTHFR) gene is associated with DNA hypomethylation, an established hallmark of human cancer cells. The aim of this study was to examine the effect of MTHFR polymorphism C677T on cervical carcinogenesis in the context of other environmental factors, such as smoking, parity, and age at the first intercourse.

METHODS

The study subjects were patients who were pathologically diagnosed with cervical neoplasia and who had a positive result for human papillomavirus (N = 462), and they were compared to normal healthy women as normal controls (N = 454). Genotypes of the patients and control samples were assayed by single base primer extension assay using SNapShot assay kit.

RESULTS

Compared with MTHFR C/C, the odds ratio (95% confidence interval) for MTHFR T/T was 1.4 (0.9-2.3) for invasive cervical cancer and 1.3 (0.8-2.3) for cervical intraepithelial neoplasia (CIN) II or III. The risks for invasive cervical cancer were higher with less than 40 years old at diagnosis (2.1, 1.0-4.3), than with over 40 years old at diagnosis (1.2, 0.7-2.2). Current smoking women with early onset with MTHFR T/T had a 4.7 (0.6-36.2) times higher risk of cervical cancer. The risks of MTHFR T/T or C/T also increased for women with an early age of first intercourse or for women with two or more children, as compared with MTHFR C/C.

CONCLUSION

Polymorphisms of MTHFR are associated with a higher risk of developing cervical cancer, and in particular for an early onset of cervical carcinogenesis.

Folate, vitamin B12, and homocysteine status. findings of no relation between human papillomavirus persistence and cervical dysplasia

OBJECTIVES

Human papillomavirus (HPV) infections are the cause of most, if not all, cervical cancers. Women consistently positive for oncogenic type HPV infections have a greater risk of developing cervical dysplasia compared with women transiently infected. HPV infection alone appears to be insufficient to produce disease, suggesting that other cofactors may be needed. Folate, vitamin B12, and homocysteine, through their role in DNA methylation, may be involved in cervical neoplasia.

METHODS

This study examined the associations between HPV persistence and circulating folate, vitamin B12, and homocysteine levels among 91 low-income Hispanic women. Further, the relation of these nutrients to cervical pathology was evaluated. HPV status was determined at two visits approximately 3 mo apart.

RESULTS

Adjusted mean circulating concentrations of folate, vitamin B12, and homocysteine were not statistically different between women with two positive HPV tests, one positive test, or two negative HPV tests. No association was observed between tertiles of folate, vitamin B12, or homocysteine and HPV persistence risk. Further, adjusted mean levels of these nutrients were not statistically different between cytologic grades.

CONCLUSIONS

Results from this small study did not support a role for folate, vitamin B12, or homocysteine in HPV persistence or cervical dysplasia.

News and views on folate and elderly persons

Elderly persons are especially exposed to folate deficiency, where normal/subnormal folate levels do not exclude tissue deficiency. Accompanying diseases, medication, and lifestyle factors may contribute to/cause deficiency. Symptoms of deficiency can be hematological, neurological, or neuropsychiatric, but it is likely that there are also cardiovascular manifestations as well as associations with malignancies. The physician should make an individualized investigation to establish the probable cause. Among the available determinants of the folate/cobalamin state, plasma homocysteine (Hcy) is a swift and sensitive marker and has the strongest connection to cognitive function. The association is generally stronger between Hcy levels and symptoms than between vitamin-related levels and symptoms. The duration as well as the severity of symptoms are of importance in terms of the improvement of neurological and neuropsychiatric symptoms when substitution is performed. The issue of general folate fortification of flour is complex, and there are as many pros and cons as there are countries in which it is considered to be launched. It is important to bear in mind that in our modern society, deficiency of folate/cobalamin--overt or latent--mainly is a problem of the elderly and a challenge to the doctor.

Management of precursor lesions of cervical carcinoma: history, host defense, and a survey of modalities

Before the initiation of screening and treatment for cervical cancer precursors, approximately 3% to 4% of women were destined to eventually develop cervical cancer. During the last 50 years the rate of cervical cancer incidence and mortality has decreased by more than 75% primarily because of the widespread availability of cervical cytologic screening and of treatment for documented cervical precancer. Successful screening of the entire population and appropriate treatment of lesions could theoretically reduce this risk to one tenth of the risk of an unscreened population [7,28]. The relatively recent understanding of the etiology of cervical cancer precursor lesions and of the immune response to them has given new direction to management options that incorporate healthy habits and dietary measures as part of traditional ablative or excisional treatment options. As we look to the future we can expect that new markers that more specifically identify individuals at-risk for cervical precancer and cancer will be developed and take precedence in cervical screening. At the same time, treating the cause of these lesions, rather than the result, should provide less traumatic and more successful therapies. To this end, harnessing the immune system through immune response modifiers and HPV vaccines seems to be on the horizon, as do new chemopreventative approaches. Of all human cancers, only cervical cancer, once the second most common cancer among women, stands on the threshold of being virtually eliminated.

Relationship of folate to colorectal and cervical cancer: review and recommendations for practitioners

Evidence suggests that folate may play a role in cancer prevention. A plausible mechanism for prevention lies in the integral role that folate plays in deoxyribonucleic acid (DNA) synthesis and methylation. DNA methylation most likely regulates gene expression. Abnormal methylation, specifically hypomethylation, has been associated with tumorigenesis. The availability of methyl groups needed for adequate DNA methylation may be negatively influenced by low folate status, alcohol intake, or genetic polymorphisms that affect folate metabolism. Observational studies evaluating the association between folate and risk for colorectal and cervical cancers or precancerous conditions have produced conflicting results, and clinical trial data are needed to confirm a cause-and-effect relationship. However, several studies show interesting associations between cancer risk and factors that influence methyl group availability. Although data relating folate to cancer risk remain equivocal, when coupled with the other potential health benefits associated with folate, evidence supports recommending that people consume folate-rich foods such as fruits and vegetables. People consuming alcohol on a daily basis may especially benefit from additional folate in their diets.

Nutritional and genetic inefficiencies in one-carbon metabolism and cervical cancer risk

Folate deficiency has long been postulated to play a role in the etiology of cervical cancer, the third most frequent cancer among women worldwide. In a large, multiethnic community-based case-control study of invasive cervical cancer in five U.S. areas, we assessed accepted and postulated risk factors with an in-home interview and successfully obtained blood samples, at least 6 mo after completion of cancer treatment, from 51 and 68%, respectively, of interviewed cases and controls. Cases with advanced disease (6%) and/or receiving chemotherapy (4%) were excluded, leaving 183 cases and 540 controls. Serum and red blood cell folate were measured with both microbiologic and radiobinding assays. For all four folate measures, risk was moderately, but nonsignificantly, elevated for women in the lowest quartile, compared to the highest [fully adjusted relative risks (RR), including serologic human papillomavirus (HPV)-16 status = 1.2-1.6]. However, for women in the upper three homocysteine quartiles (>6.31 micro mol/L), risk of invasive cervical cancer was substantially and significantly elevated (fully adjusted RR, including serologic HPV-16 status = 2.4-3.2; P for trend = 0.01). This strong relationship suggests that circulating homocysteine may be 1) an especially accurate indicator of inadequate folate, 2) an integratory measure of insufficient folate in tissues or 3) a biomarker of disruption of one-carbon metabolism. The contribution of common polymorphisms in one-carbon pathway genes, as well as inadequate vitamin B-6, vitamin B-12 and/or riboflavin, to elevated homocysteine, inefficient one-carbon metabolism and increased cervical cancer risk merits further exploration.