Effect of smoking on folate levels in buccal mucosal cells

High frequencies of vitamin B12 and folic acid deficiencies and hyperhomocysteinemia in Taiwanese male patients with oral submucous fibrosis

Background

/purpose: Oral submucous fibrosis (OSF) is a betel quid chewing-caused oral mucosal disease with progressive collagen deposition. This study evaluated whether Taiwanese male OSF patients had high frequencies of vitamin B12 and folic acid deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity.

Materials and methods

The blood hemoglobin (Hb), serum iron, vitamin B12, folic acid, homocysteine, and GPCA concentrations in 62 male OSF patients were measured and compared with the corresponding data in 124 age-matched male healthy control subjects.

Results

We found that 5 (8.1%), 12 (19.4%), 32 (51.6%), 31 (50.0%), 22 (35.5%), and 6 (9.7%) of the 62 male OSF patients had Hb (<13 g/dL), iron (≤70 μg/dL), vitamin B12 (≤450 pg/mL), and folic acid (≤6 ng/mL) deficiencies, hyperhomocysteinemia (>12 μM), and serum GPCA positivity, respectively. Furthermore, OSF patients had significantly higher frequencies of Hb (P = 0.006), vitamin B12 (P < 0.001), and folic acid (P < 0.001) deficiencies, hyperhomocysteinemia (P < 0.001), and serum GPCA positivity (P = 0.030) than 124 healthy control subjects. Of the 22 OSF patients with hyperhomocysteinemia, 4 had vitamin B12 deficiency only, 7 had folic acid deficiency only, and 11 had both vitamin B12 and folic acid deficiencies.

Conclusion

We conclude that Taiwanese male OSF patients have high frequencies of vitamin B12 and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity. The hyperhomocysteinemia in our OSF patients is predominantly due to deficiencies of either vitamin B12 or folic acid or both.

Higher frequencies of anemia, vitamin B12 deficiency, and gastric parietal cell antibody positivity in folic acid-deficient Taiwanese male oral submucous fibrosis patients

Background/purpose

Oral submucous fibrosis (OSF) is a progressive fibrotic oral mucosal disease associated with betel quid chewing. This study evaluated whether Taiwanese male OSF patients with folic acid (FA) deficiency (the serum FA level ≤6 ng/mL, so-called FA-deficient OSF patients) had high frequencies of blood hemoglobin (Hb) and serum iron and vitamin B12 deficiencies, and serum gastric parietal cell antibody (GPCA) positivity.

Materials and methods

The blood Hb and serum iron, vitamin B12, FA, and GPCA concentrations in 59 Taiwanese male FA-deficient OSF patients were measured and compared with the corresponding data in 118 age-matched healthy male control subjects.

Results

We found that 3 (5.1%), 35 (59.3%), and 7 (11.9%) of the 59 FA-deficient OSF patients had blood Hb (<13 g/dL) and serum vitamin B12 (≤450 pg/mL) deficiencies, and serum GPCA positivity, respectively. Furthermore, 59 FA-deficient OSF patients had significantly higher frequencies of serum vitamin B12 deficiency and serum GPCA positivity than 118 healthy control subjects (all P-values <0.05). Of the 3 anemic FA-deficient OSF patients, one had macrocytic anemia and the other two had thalassemia trait-induced anemia.

Conclusion

We conclude that Taiwanese male FA-deficient OSF patients have high frequencies of serum vitamin B12 deficiency and GPCA positivity than healthy control subjects. The vitamin B12 and FA deficiencies in FA-deficient OSF patients are more likely due to OSF symptoms and signs-caused insufficient intake, difficulty in chewing and swallowing, and malabsorption of food fragment-bound vitamin B12 and FA rather than the GPCA positivity in these OSF patients.

Higher frequencies of anemia, hematinic deficiencies, and gastric parietal cell antibody positivity in vitamin B12-deficient Taiwanese male oral submucous fibrosis patients

Abstract Background/purpose

Oral submucous fibrosis (OSF) is a progressive fibrotic oral mucosal disease associated with betel quid chewing. This study evaluated whether Taiwanese male OSF patients with vitamin B12 deficiency (the serum vitamin B12 level ≤ 450 pg/mL, B12-deficient OSF patients) had high frequencies of blood hemoglobin (Hb) and serum iron and folic acid deficiencies, and serum gastric parietal cell antibody (GPCA) positivity.

Materials and methods

The blood Hb and serum iron, vitamin B12, folic acid, and GPCA concentrations in 66 Taiwanese male B12-deficient OSF patients were measured and compared with the corresponding data in 132 age-matched healthy male control subjects.

Results

We found that 6 (9.1%), 19 (28.8%), 35 (53.0%), and 9 (13.6%) of the 66 B12-deficient OSF patients had blood Hb (<13 g/dL) and serum iron (≤70 μg/dL), and folic acid (≤6 ng/mL) deficiencies, and serum GPCA positivity, respectively. Furthermore, 66 OSF patients had significantly higher frequencies of blood Hb and serum iron and folic acid deficiencies, and serum GPCA positivity than 132 healthy control subjects (all P-values < 0.05). Of the 6 anemic B12-deficient OSF patients, one had macrocytic anemia, two normocytic anemia, and three thalassemia trait-induced anemia.

Conclusion

Taiwanese male B12-deficient OSF patients have high frequencies of blood Hb, serum iron and folic acid deficiencies, and serum GPCA positivity. The anemia and hematinic deficiencies in B12-deficient OSF patients are likely due to OSF symptoms and signs-caused insufficient intake, poor chewing, and malabsorption of hematinic elements from ingested food stuffs rather than the GPCA positivity.

Significantly lower mean serum vitamin B12 and folic acid levels and a significantly higher frequency of serum iron deficiency in younger than in older atrophic glossitis patients

Background/purpose

: Our previous study found that 19.0%, 16.9%, 5.3%, 2.3%, and 11.9% of 1064 atrophic glossitis (AG) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, and hyperhomocysteinemia, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 224 younger (≤50 years old) and 840 older (>50 years old) AG patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, and homocysteine levels in 224 younger and 840 older AG patients were measured and compared with the corresponding levels in 112 younger (≤50 years old) and 420 older (>50 years old) healthy control subjects (HCSs), respectively.

Results

We found that 224 younger AG patients had significantly lower mean blood Hb and serum iron levels than 112 younger HCSs. Moreover, 840 older AG patients had significantly lower mean blood Hb and serum iron levels and a significantly higher mean serum homocysteine level than 420 older HCSs. In addition, 224 younger AG patients had significantly lower mean serum vitamin B12 and folic acid levels, a lower mean serum homocysteine level (marginal significance, P = 0.056), a significantly higher frequency of serum iron deficiency, and a significantly lower frequency of hyperhomocysteinemia than 840 older AG patients.

Conclusion

The younger AG patients do have significantly lower mean serum vitamin B12 and folic acid levels, a significantly higher frequency of serum iron deficiency, and a significantly lower frequency of hyperhomocysteinemia than the older AG patients.

Significantly higher frequencies of macrocytosis, anemia, serum vitamin B12 and folic acid deficiencies, and hyperhomocysteinemia in male than in female atrophic glossitis patients

Background/purpose

Our previous study found that 19.0%, 16.9%, 5.3%, 2.3%, 11.9%, and 26.7% of 1064 atrophic glossitis (AG) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity, respectively. This study evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 150 male and 914 female AG patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, GPCA levels in 150 male and 914 female AG patients were measured and compared with the corresponding levels in 75 male and 457 female healthy control subjects (HCSs), respectively.

Results

We found that 150 male AG patients had significantly lower mean blood Hb, serum iron, vitamin B12, and folic acid levels, and significantly higher mean serum homocysteine levels than 75 male HCSs. Moreover, 914 female AG patients had significantly lower mean blood Hb and serum iron levels and significantly higher mean serum homocysteine level than 457 female HCSs. In addition, 150 male AG patients had significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of Hb, vitamin B12, and folic acid deficiency and hyperhomocysteinemia than 914 female AG patients.

Conclusion

The male AG patients do have significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of Hb, vitamin B12, and folic acid deficiencies and hyperhomocysteinemia than the female AG patients.

Anemia, hematinic deficiencies, and hyperhomocysteinemia in younger and older burning mouth syndrome patients

Abstract Background/purpose

Our previous study found that 19.8%, 16.2%, 4.8%, 2.3%, and 19.2% of 884 burning mouth syndrome (BMS) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, and hyperhomocysteinemia, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 272 younger (≤50 years old) and 612 older (>50 years old) BMS patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, and homocysteine levels in 272 younger and 612 older BMS patients were measured and compared with the corresponding levels in 136 younger (≤50 years old) and 306 older (>50 years old) healthy control subjects (HCSs), respectively.

Results

We found that 272 younger BMS patients had significantly lower mean blood Hb and serum iron, vitamin B12, and folic acid levels than 136 younger HCSs. Moreover, 612 older BMS patients had significantly lower mean blood Hb, and serum iron and vitamin B12 levels and significantly higher mean serum homocysteine level than 306 older HCSs. In addition, 272 younger BMS patients had higher mean blood Hb level (marginal significance, P = 0.056), significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of iron and folic acid deficiencies than 612 older BMS patients.

Conclusion

The younger BMS patients do have higher mean blood Hb level, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of serum iron and folic acid deficiencies than the older BMS patients.

Association of MTHFD1 gene polymorphisms and maternal smoking with risk of congenital heart disease: a hospital-based case-control study

Background

MTHFD1 gene may affect the embryonic development by elevated homocysteine levels, DNA synthesis and DNA methylation, but limited number of genetic variants of MTHFD1 gene was focused on the association with congenital heart disease (CHD). This study examined the role of MTHFD1 gene and maternal smoking on infant CHD risk, and investigated their interaction effects in Chinese populations.

Methods

A case-control study of 464 mothers of CHD infants and 504 mothers of health controls was performed. The exposures of interest were maternal tobacco exposure, single nucleotide polymorphisms (SNPs) of maternal MTHFD1 gene. The logistic regression model was used for accessing the strength of association.

Results

Mothers exposed to secondhand smoke during 3 months before pregnancy (adjusted odds ratio [aOR] = 1.56; 95% confidence interval [CI]: 1.13–2.15) and in the first trimester of pregnancy (aOR = 2.24; 95%CI: 1.57–3.20) were observed an increased risk of CHD. Our study also found that polymorphisms of maternal MTHFD1 gene at rs1950902 (AA vs. GG: aOR = 1.73, 95% CI: 1.01–2.97), rs2236222 (GG vs. AA: aOR = 2.38, 95% CI: 1.38–4.12), rs1256142 (GA vs.GG: aOR = 1.57, 95% CI: 1.01–2.45) and rs11849530 (GG vs. AA: aOR = 1.68, 95% CI: 1.02–2.77) were significantly associated with higher risk of CHD. However, we did not observe a significant association between maternal MTHFD1 rs2236225 and offspring CHD risk. Furthermore, we found the different degrees of interaction effects between polymorphisms of the MTHFD1 gene including rs1950902, rs2236222, rs1256142, rs11849530 and rs2236225, and maternal tobacco exposure.

Conclusions

Maternal polymorphisms of MTHFD1 gene, maternal tobacco exposure and their interactions are significantly associated with the risk of CHD in offspring in Han Chinese populations. However, more studies in different ethnic populations with a larger sample and prospective designs are required to confirm our findings.

Trial registration

Registration number: ChiCTR1800016635.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04419-2.

Anemia, hematinic deficiencies, and hyperhomocysteinemia in male and female burning mouth syndrome patients

Background/purpose

Our previous study found that 19.8%, 16.2%, 4.8%, 2.3%, 19.2%, and 12.3% of 884 burning mouth syndrome (BMS) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 212 male and 672 female BMS patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, GPCA levels in 212 male and 672 female BMS patients were measured and compared with the corresponding levels in 106 male and 336 female healthy control subjects, respectively.

Results

We found that 212 male BMS patients had significantly lower mean blood Hb, serum iron, vitamin B12, and folic acid levels and significantly higher mean serum homocysteine levels than 106 male healthy control subjects. Moreover, 672 female BMS patients had significantly lower mean blood Hb and serum iron levels and significantly higher mean serum homocysteine level than 336 female healthy control subjects. In addition, 212 male BMS patients had significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of folic acid deficiency and hyperhomocysteinemis than 672 female BMS patients.

Conclusion

The male BMS patients do have significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of folic acid deficiency and hyperhomocysteinemis than the female BMS patients.

Higher serum homocysteine level and frequency of hyperhomocysteinemia in carcinoembryonic antigen-positive or squamous cell carcinoma-antigen-positive oral leukoplakia patients

BACKGROUND/PURPOSE

Our previous study found significantly lower serum hematinic levels and higher serum homocysteine level as well as higher frequencies of serum hematinic deficiencies and hyperhomocysteinemia in oral leukoplakia (OL) patients than in healthy control subjects. This study evaluated whether carcinoembryonic antigen (CEA)-positive or squamous cell carcinoma-antigen (SCC-Ag)-positive OL patients had significantly lower serum hematinic levels and higher serum homocysteine level as well as significantly higher frequencies of hematinic deficiencies and hyperhomocysteinemia than CEA-negative or SCC-Ag-negative OL patients or healthy control subjects.

METHODS

The complete blood count, serum iron, vitamin B12, folic acid, and homocysteine levels in 184 OL patients including 85 CEA-positive, 99 CEA-negative, 25 SCC-Ag-positive, and 159 SCC-Ag-negative OL patients and in 184 age- and sex-matched healthy control subjects were measured and compared.

RESULTS

We found that the 85 CEA-positive or 25 SCC-Ag-positive OL patients had a significantly lower mean serum folic acid level and a significantly higher mean serum homocysteine level as well as significantly higher frequencies of serum folic acid deficiency and hyperhomocysteinemia than 184 healthy control subjects. Moreover, the 25 SCC-Ag-positive OL patients had a significantly higher mean serum homocysteine level than the 159 SCC-Ag-negative OL patients. The 85 CEA-positive OL patients had a higher mean serum homocysteine level and a higher frequency of hyperhomocysteinemia than 99 CEA-negative OL patients (marginally significant, P = 0.060).

CONCLUSION

CEA-positive or SCC-Ag-positive OL patients tend to have a higher mean serum homocysteine level and a higher frequency of hyperhomocysteinemia than CEA-negative or SCC-Ag-negative OL patients, respectively.

The Cigarette Smoking, Coffee and Supplements Intake at Students of Sarajevo University

Introduction:

The dietary supplements are defined as vitamins and minerals or herbal products and are typically given in the form of a capsule or tablet. The nonsmokers are more attempted to use dietary supplements than individuals who smoke.

Aim:

In our investigation, we examined associations between vitamin B, folic acid, multivitamin or mineral intake among the student population and their correlation with smoking prevalence and drinking coffee.

Materials and methods:

We used a questionnaire to examine the general characteristics of the subjects, age, sex, their lifestyle, cigarette smoking, coffee intake and their use of dietary supplements. Data were collected from participants of the University of Sarajevo and a longitudinal study of 960 men and women aged 18-24 years from 2017 to 2018 was conducted.

Results:

The results showed that 32% of students took vitamin B supplements and 10% folic acid. In opposite, more than half of students took multivitamins (59.5%) and minerals (60.4%) less than one year. About a quarter or less took multivitamins (23.9%) and minerals (24.3%) for years. Less than 20% of students took multivitamins and minerals within a period of one year. In student population smoking prevalence was estimated at 21.2% and coffee intake in 71.2%. The smoking and use of vitamin B supplements were independent of each other, p = 0.201. The use of folic acid did not depend on smoking p = 0.501. There were no observed correlations between multivitamin and mineral supplement consumption compared to smoking status or drinking coffee.

Conclusion:

Deficient dietary intake of folic acid and B vitamins from food and supplemental sources appear to be one of the atherosclerosis incidences. Further studies should examine associations between dietary supplements intake and lifestyle of students, as well as smoking status and coffee intake.

The impact of folate intake on the risk of head and neck cancer in the prostate, lung, colorectal, and ovarian cancer screening trial (PLCO) cohort

BACKGROUND

Although low levels of folate leads to disturbances in DNA replication, DNA methylation and DNA repair, the association between dietary folate intake and head and neck cancer (HNC) risk remains unclear.

METHODS

We evaluated the association between folate intake and HNC risk using prospective cohort data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial. This study included 101 700 participants and 186 cases with confirmed incident HNC. The median follow-up was 12.5 years. We estimated hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) using Cox proportional hazard model including age, sex, body mass index, education, race, tobacco smoking, alcohol drinking and total fruit and vegetable intake.

RESULTS

Higher intake of food folate and fortified folic acid in foods was associated with a decreasing HNC risk in a dose-response manner. The HRs of highest vs the lowest quartile of intake were 0.35 (95%CI: 0.18-0.67) for food folate, and 0.49 (95%CI: 0.30-0.82) for fortified folic acid. Intakes of total folate, natural folate and supplemental folic acid were not associated with the risk of HNC and its subsites. We did not detect any interaction between smoking, drinking and food folate intake on HNC risk.

CONCLUSIONS

These findings provide evidence of the protective role of dietary folate intake on HNC risk.

MTHFR methylation moderates the impact of smoking on DNA methylation at AHRR for African American young adults

Smoking has been shown to have a large, reliable, and rapid effect on demethylation of AHRR, particularly at cg05575921, suggesting that methylation may be used as an index of cigarette consumption. Because the availability of methyl donors may also influence the degree of demethylation in response to smoking, factors that affect the activity of methylene tetrahydrofolate reductase (MTHFR), a key regulator of methyl group availability, may be of interest. In the current investigation, we examined the extent to which individual differences in methylation of MTHFR moderated the association between smoking and demethylation at cg05575921 as well as at other loci on AHRR associated with a main effect of smoking. Using a discovery sample (AIM, N = 293), and a confirmatory sample (SHAPE, N = 368) of young adult African Americans, degree of methylation of loci in the first exon of MTHFR was associated with amplification of the association between smoking and AHRR demethylation at cg05575921. However, genetic variation at a commonly studied MTHFR variant, C677T, did not influence cg05575921 methylation. The significant interaction between MTHFR methylation and the smoking-induced response at cg05575921 suggests a role for individual differences in methyl cycle regulation in understanding the effects of cigarette consumption on genome wide DNA methylation.

Global DNA hypomethylation is associated with the development and poor prognosis of tongue squamous cell carcinoma

BACKGROUNDS

Oral cancer is the 4th leading cause of cancer death for males and the top cancer in young adult males in Taiwan. Tongue squamous cell carcinoma (TSCC) is a common oral cancer and generally associated with poor prognosis. Global DNA hypomethylation at the 5 position of cytosine (5mC) is a well-known epigenetic feature of cancer. Therefore, the purpose of this study was to investigate the relationship of the global 5mC content with the tumorigenesis and prognosis of patients with TSCC.

METHODS

The levels of global 5mC were evaluated by immunohistochemistry using tissue microarray slides of 248 surgically resected TSCC and 202 corresponding tumor adjacent normal (TAN) tissues.

RESULTS

We found that the level of 5mC in TSCC (P < 0.001) was significantly decreased as compared to TAN. Among TSCC tissues, decreased levels of 5mC were associated with female gender (P = 0.036). In addition, the global hypomethylation was associated with the poor disease-specific survival in TSCC patients (adjusted hazard ratio: 1.55, P = 0.043), especially for patients in older age group (> 50 years, P = 0.013), with moderate or poor cell differentiation (P = 0.044), early stage of disease (I-II, P = 0.046), small tumor size (T1-T2, P = 0.005), without lymph node involvement (P = 0.041), and ever received postoperative radiotherapy (P = 0.009).

CONCLUSIONS

Global hypomethylation was an independent biomarker for the development and poor prognosis of TSCC.

Folate intake and the risk of oral cavity and pharyngeal cancer: a pooled analysis within the International Head and Neck Cancer Epidemiology Consortium

There are suggestions of an inverse association between folate intake and serum folate levels and the risk of oral cavity and pharyngeal cancers (OPCs), but most studies are limited in sample size, with only few reporting information on the source of dietary folate. Our study aims to investigate the association between folate intake and the risk of OPC within the International Head and Neck Cancer Epidemiology (INHANCE) Consortium. We analyzed pooled individual-level data from ten case-control studies participating in the INHANCE consortium, including 5,127 cases and 13,249 controls. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were estimated for the associations between total folate intake (natural, fortification and supplementation) and natural folate only, and OPC risk. We found an inverse association between total folate intake and overall OPC risk (the adjusted OR for the highest vs. the lowest quintile was 0.65, 95% CI: 0.43-0.99), with a stronger association for oral cavity (OR = 0.57, 95% CI: 0.43-0.75). A similar inverse association, though somewhat weaker, was observed for folate intake from natural sources only in oral cavity cancer (OR = 0.64, 95% CI: 0.45-0.91). The highest OPC risk was observed in heavy alcohol drinkers with low folate intake as compared to never/light drinkers with high folate (OR = 4.05, 95% CI: 3.43-4.79); the attributable proportion (AP) owing to interaction was 11.1% (95% CI: 1.4-20.8%). Lastly, we reported an OR of 2.73 (95% CI:2.34-3.19) for those ever tobacco users with low folate intake, compared with nevere tobacco users and high folate intake (AP of interaction =10.6%, 95% CI: 0.41-20.8%). Our project of a large pool of case-control studies supports a protective effect of total folate intake on OPC risk.

Systemic folate status, rectal mucosal folate concentration and dietary intake in patients at differential risk of bowel cancer (The FAB2 Study)

BACKGROUND/OBJECTIVES

Folate has been strongly implicated in the aetiology of colorectal cancer. However, the relationship between dietary folate intake, rectal mucosal folate status and colorectal cancer risk is uncertain. The study aimed to estimate nutrient intakes and measure systemic folate status and rectal mucosal folate concentration in people at differential risk of developing colorectal cancer.

METHODS

Two hundred and twenty-eight individuals were recruited from gastroenterology clinics and subdivided into three patient groups: untreated colorectal cancer (n = 43), adenomatous polyps (n = 90) or normal bowel (n = 95). Biopsies from macroscopically normal rectal mucosa and blood were collected and used for the measurement of rectal mucosal 5-methyltetrahydrofolate (5-MeTHF) and systemic markers of folate status, respectively. Nutrient intake was estimated using a validated food frequency questionnaire.

RESULTS

Dietary intake variables, plasma 5-MeTHF and red cell folate and plasma homocysteine concentrations were similar in all three subject groups and 95% CI fell within normal range for each variable. Rectal mucosal 5-MeTHF concentration was higher in the normal mucosa of adenomatous polyp patients than in normal subjects (P = 0.055). Rectal mucosal 5-MeTHF was associated significantly with plasma folate (P < 0.001, r = 0.294), red cell folate (P = 0.014, r = 0.305), plasma homocysteine (P = 0.017, r = -0.163) and dietary folate intake (P = 0.036, r = 0.152).

CONCLUSIONS

This study demonstrates adequate folate status of patients attending gastroenterology clinics for the investigation of bowel symptoms, with no significant difference in dietary intakes or systemic folate status indices according to diagnosis. Rectal mucosal 5-MeTHF concentrations were elevated in adenomatous polyp patients, but failed to reach significance. Further studies are required to determine the biological significance of this observation.

Methylenetetrahydrofolate reductase polymorphisms and interaction with smoking and alcohol consumption in lung cancer risk: a case-control study in a Japanese population

Background

Cigarette smoking is an established risk factor of lung cancer development while the current epidemiological evidence is suggestive of an increased lung cancer risk associated with alcohol consumption. Dietary folate, which is present in a wide range of fresh fruits and vegetables, may be a micronutrient that has a beneficial impact on lung carcinogenesis. Methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in regulating folate metabolism, which affects both DNA synthesis/repair and methylation. We examined if smoking or alcohol consumption modify associations between MTHFR polymorphisms and lung cancer risk.

Methods

We evaluated the role of the MTHFR C677T (rs1801133) and A1298C (rs1801131) polymorphisms in a case-control study comprised of 462 lung cancer cases and 379 controls in a Japanese population. Logistic regression was used to assess the adjusted odds ratios (OR) and 95% confidence intervals (95% CI).

Results

The TT genotype of the C677T polymorphism was significantly associated with an increased risk of lung cancer (OR = 2.27, 95% CI = 1.42 - 3.62, P < 0.01) while the A1298C polymorphism was not associated with lung cancer risk. The minor alleles of both polymorphisms behaved in a recessive fashion. The highest risks were seen for 677TT-carriers with a history of smoking or excessive drinking (OR = 6.16, 95% CI = 3.48 - 10.9 for smoking; OR = 3.09, 95% CI = 1.64 - 5.81 for drinking) compared with C-carriers without a history of smoking or excessive drinking, but no interactions were seen. The 1298CC genotype was only associated with increased risk among non-smokers (P < 0.05), and smoking was only associated with increased risks among 1298A-carriers (P < 0.01), but no significant interaction was seen. There was a synergistic interaction between the A1298C polymorphism and drinking (P < 0.05). The highest risk was seen for the CC-carriers with excessive drinking (OR = 7.24, 95% CI = 1.89 - 27.7) compared with the A-carriers without excessive drinking).

Conclusions

The C677T polymorphism was significantly associated with lung cancer risk. Although the A1298C polymorphism was not associated with lung cancer risk, a significant interaction with drinking was observed. Future studies incorporating data on folate intake may undoubtedly lead to a more thorough understanding of the role of the MTHFR polymorphisms in lung cancer development.

Line region hypomethylation is associated with lifestyle and differs by human papillomavirus status in head and neck squamous cell carcinomas

Genomic hypomethylation is a hallmark of essentially all cancers, but the degree of this hypomethylation differs among individual tumors. Little work has explored what leads to these differences and or asked whether they are clinically meaningful. In this study of head and neck squamous cell carcinoma, we assessed hypomethylation in tumors using a semiquantitative fragment analysis approach to determine the relative methylation status of the line retroviral element LRE1 (Line-1.2). Because this is an established marker of genomic methylation status, we examined the relationship between the relative methylation, patient demographics, and other risk factors for head and neck squamous cell carcinoma. We determined relative methylation status for 303 patients, 193 of which had complete data for all variables of interest. Using a generalized linear model, we found that patient body mass index was significantly positively associated with tumor LRE1 methylation level. Smoking duration, particularly in tumors lacking human papillomavirus (HPV) DNA, was significantly negatively associated with relative methylation level. Having previously assessed relative methylation in blood-derived DNA, we compared tumor with the blood DNA methylation level and observed these to be independent. Finally, the lower LRE1 methylation in patients whose tumors were HPV DNA negative was associated with poorer patient survival (hazard ratio, 1.6; 95% confidence interval, 1.0-2.6). These findings suggest that HPV-associated tumors differ molecularly from those arising after heavy tobacco use and that this epigenetic alteration may affect survival in HPV-negative patients already exhibiting a more aggressive disease.

Relationship between smoking and folic acid, vitamin B12 and some haematological variables in patients with chronic periodontal disease

AIM

The purpose of this study was to investigate the relationship between cigarette smoking and the serum levels of folic acid, vitamin B(12) and some haematological variables in patients with periodontal disease.

PATIENTS AND METHODS

The study base consisted of 88 volunteer patients with periodontal disease, including 45 current smokers in the age range 31-68 years and 43 non-smokers in the range 32-66 years. The clinical parameters included plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD) and clinical attachment loss (CAL). Folic acid, vitamin B(12) and haematological variables were determined from peripheral blood samples.

RESULTS

PI, PD and CAL means were significantly higher in smokers than non-smokers (p<0.05). The serum folic acid concentration of smokers was lower than that of non-smokers (p<0.05), whereas the white blood cell count was higher in smokers than in non-smokers (p<0.05).

CONCLUSION

The results of this study suggest that among patients with periodontal disease the serum folic acid concentration is lower in smokers compared with non-smokers.

Effect of fortified spread on homocysteine concentration in apparently healthy volunteers

OBJECTIVE

To determine the effect of folic acid, vitamin B(6) and B(12) fortified spreads on the blood concentrations of these vitamins and homocysteine.

DESIGN AND SETTING

A 6-week randomized, double-blinded, placebo-controlled, parallel trial carried out in a clinical research center.

SUBJECTS

One hundred and fifty healthy volunteers (50% males).

INTERVENTIONS

For 6 weeks, the subjects consumed the test spreads (20 g/day): containing per 20 g (1) 200 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6), or (2) 400 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6) or (3) no B-vitamins (control spread).

RESULTS

The B-vitamin status increased on using the test spreads, with the largest effect on the serum folate concentration: 48% in men and 58% in women on spread 1 and 92 and 146%, respectively, on spread 2 (P-values all <0.05). The plasma homocysteine decreased in the groups treated with the fortified spreads as compared to the control group. Average decreases were for males: 0.7+/-1.5 micromol/l (6.8%) on spread 1 and 1.7+/-1.7 micromol/l (17.6%) on spread 2 and for females: 1.4+/-1.2 micromol/l (14.2%) and 2.4+/-2.0 micromol/l (23.3%), respectively (P-values all <0.05).

CONCLUSIONS

Consumption of a spread fortified with folic acid, vitamin B(6) and vitamin B(12) for 6 weeks significantly increases the blood concentrations of these vitamins and significantly decreases the plasma concentration of homocysteine. Fortified staple foods like spreads can contribute to the lowering of homocysteine concentrations.

Homocysteine and coronary heart disease risk in the PRIME study

INTRODUCTION

Despite recent meta-analyses suggesting that homocysteine is an independent predictor of coronary heart disease (CHD), there is debate regarding whether elevated homocysteine may be deleterious only in the presence of other risk factors, with which it acts synergistically to exert a multiplicative effect on CHD risk, emerging only as a CHD predictor in patients with pre-existing risk factors. The Prospective Epidemiological Study of Myocardial Infarction (PRIME) Study is a multicentre prospective study of 10593 men from France and Northern Ireland, investigating cardiovascular risk factors. We investigated: (1) whether higher homocysteine is associated with increased CHD risk in the PRIME case-control cohort; (2) whether homocysteine interacts synergistically with pre-existing CHD risk factors.

METHODS

Homocysteine was measured in 323 participants who had developed CHD at 5-year follow-up and in 638 matched controls.

RESULTS

There was no significant difference in homocysteine between cases and controls (p=0.18). Homocysteine was significantly higher in current smokers (geometric mean mumol/l (interquartile range mumol/l) 9.45 (7.43, 11.75)) compared with non-smokers (8.90 (7.32, 10.70); p=0.007). There was a significant interaction between homocysteine, smoking and CHD risk (chi2=10.29, d.f.=2, p=0.006).

CONCLUSIONS

These findings suggest that elevated homocysteine is significantly associated with CHD risk in current smokers.

Chronic cigarette smoking is associated with diminished folate status, altered folate form distribution, and increased genetic damage in the buccal mucosa of healthy adults

BACKGROUND

Smoking causes genetic damage in buccal cells and increases the risk of oral cancer. Because folate is instrumental in DNA synthesis and repair, it is a determinant of genetic stability and therefore might attenuate the genotoxic effects of smoking.

OBJECTIVE

Our aim was to compare the presence of folate metabolites and select indicators of genetic damage in the mouths of chronic smokers and nonsmokers.

DESIGN

Dietary, biochemical, and molecular correlates of folate status were measured in healthy smoker (n = 35) and nonsmoker (n = 21) groups of comparable age, sex, and body mass indexes.

RESULTS

After correction for dietary intake, the smokers displayed lower plasma, erythrocyte, and buccal mucosal cell (BMC) folate (20%, 32%, and 50% lower, respectively; P < 0.05) and lower plasma vitamin B-12 and pyridoxal 5-phosphate (P < 0.05) than did nonsmokers. Folate in the BMCs of smokers comprised significantly greater proportions of pteroylmonoglutamate, formyltetrahydrofolate, and 5,10-methenyltetrahyrofolate than did folate in the BMCs of nonsmokers. Although the degree of genomic methylation and uracil incorporation in the buccal cells of the 2 groups were not significantly different, the BMC micronucleus index, a cytologic indicator of genetic damage, in the smokers was 2-fold that of the nonsmokers (9.57 compared with 4.44 micronuclei/1000 cells; P < 0.0001). Neither systemic nor oral folate status was an independent predictor of micronuclei.

CONCLUSIONS

Chronic smoking is associated with a lower systemic status of several B vitamins, reduced oral folate, and changes in folate form distribution in the mouth. However, the cytologic damage that is evident in the mouths of smokers does not correlate with oral folate status.

Dietary and other lifestyle correlates of serum folate concentrations in a healthy adult population in Crete, Greece: a cross-sectional study

Background

Folate has emerged as a key nutrient for optimising health. Impaired folate status has been identified as a risk factor for cardiovascular disease, various types of cancers, and neurocognitive disorders. The study aimed at examining the distribution and determinants of serum folate concentrations in a healthy adult population in Crete, Greece.

Methods

A cross-sectional sample of 486 healthy adults (250 men, 236 women) aged 39 ± 14 years, personnel of the Medical School and the University Hospital of Crete in Greece, was examined. Serum folate and vitamin B₁₂ concentrations were measured by microbiological assay, and total homocysteine was determined fluorometrically and by high-pressure liquid chromatography. Lifestyle questionnaires were completed, and nutrient intakes and food consumption were assessed by 24-h dietary recalls. Multivariate analyses were performed using SPSS v10.1.

Results

The geometric mean (95% confidence interval) concentrations of serum folate were 15.6 μmol/l (14.6–16.8) in men and 19.2 μmol/l (17.9–20.7) in women (p < 0.001). Inadequate folate levels (≤7 nmol/l) were present in 6.8% of men and 2.1% of women (p < 0.001). Approximately 76% of men and 87% of women did not meet the reference dietary intake for folate (400 μg/day). Serum folate was inversely related to total homocysteine levels (p < 0.001). Increased tobacco and coffee consumption were associated with lower folate concentrations (p < 0.05 for both) but these associations disappeared after controlling for nutrient intakes. In multivariate analysis, intakes of MUFA, fibre, calcium, magnesium, folate, and vitamins A, E, C, B₁, and B₆ were positively associated with serum folate. Consumption of potatoes, legumes, fruits, and vegetables were favourably related to the serum folate status.

Conclusion

Serum folate concentrations were associated with various demographic, lifestyle and dietary factors in healthy Cretan adults. Large-scale epidemiological studies should be conducted within the general Greek adult population to assess the prevalence of impaired folate status and further examine associations with dietary patterns and chronic disease risk. Considering the importance of folate in health maintenance, it is important to increase the public's awareness of modifiable lifestyle patterns and diet and tobacco use in particular, which may be associated with improved folate status.

Application of the micronucleus test to exfoliated epithelial cells from the oral cavity of beedi smokers, a high-risk group for oral cancer

The primary sites for occurrence of oral cancer include the buccal mucosa, tongue, alveolus, palate, lip and the floor of the mouth. In this study, an attempt was made to estimate the cytogenetic damage in different regions of the oral mucosa in people habituated to smoking beedi,which is one of the major forms of tobacco consumption in India and believed to be a major risk factor for oral cancer. By using the micronucleus assay on exfoliated cells from the buccal mucosa, palate and tongue of beedi smokers, we examined an early cellular response to the effect of beedi smoking. A total number of 50 randomly selected male subjects were included in the study. Case and control groups (smokers and non-smokers, respectively) comprised 25 subjects each. The difference in mean micronucleated cell count between cases and controls was significant (P <0.01) for buccal mucosa and palate, but not for tongue. The correlation between age and micronucleus cell count was weak for both cases (r=0.27) and controls (r=0.36).

Effect of Folic Acid Supplementation on the Folate Status of Buccal Mucosa and Lymphocytes

Folate deficiency may be associated with an increased risk of cancer at certain sites. There is a need to measure folate status and putative biomarkers of cancer risk in the same target tissue, or in surrogate tissues. A study was carried out to develop a method for the rapid measurement of folate in human buccal mucosa and lymphocytes and to evaluate the responsiveness of this measurement in both tissues to folic acid supplementation in healthy subjects, relative to conventional markers of folate status. Three hundred and twenty-three adults, ages between 20 and 60 years, were screened for RBC folate concentrations. Sixty-five subjects with red cell folate between 200 and 650 nmol/L participated in a randomized, double blind, placebo-controlled, folic acid (1.2 mg) intervention trial, lasting 12 weeks. As anticipated, a significant baseline correlation (r = 0.36, P &lt; 0.01) was observed between red cell folate and plasma 5-methyltetrahydrofolate (5-MeTHF). Lymphocyte total folate was significantly associated with plasma 5-MeTHF (r = 0.28, P &lt; 0.05) and plasma total homocysteine concentration (r = −0.34, P &lt; 0.05). Buccal mucosa total folate showed no correlation with either red cell folate or 5-MeTHF, but was significantly associated with lymphocyte total folate (r = 0.35, P &lt; 0.01). Supplementation elicited a significant increase in lymphocyte total folate (P &lt; 0.01), and this was strongly associated with the increase in RBC total folate (P &lt; 0.01) and plasma 5-MeTHF (P &lt; 0.01). Buccal mucosa total folate was not influenced by folate supplementation. Methods have been developed for the rapid measurement of lymphocyte and buccal mucosal total folate. Lymphocyte folate is sensitive to folate intake and is reflected by plasma 5-MeTHF.

Homocysteine and its relation to B-vitamins in Graves' disease before and after treatment: effect modification by smoking

OBJECTIVES

To investigate plasma total homocysteine levels and its relation to B-vitamins and smoking in Graves' disease before and after antithyroid therapy.

DESIGN

A longitudinal study taking place at four hospitals in Norway.

METHODS AND SUBJECTS

Plasma total homocysteine, serum folate, serum cobalamin and riboflavin, flavin mononucleotide and flavin adenine dinucleotide in plasma were investigated in 182 patients with hyperthyroidism before treatment. The same parameters were reinvestigated in 112 of these patients after attaining euthyroid state.

RESULTS

In hyperthyroidism, plasma total homocysteine was low, and inversely related to folate, cobalamin and riboflavin, and positively related to serum creatinine and age. Following antithyroid therapy, total homocysteine increased and the concentration of folate, cobalamin, riboflavin, flavin mononucleotide and flavin adenine dinucleotide decreased significantly. The most pronounced reduction (35%) was observed for flavin mononucleotide. In the hyperthyroid state, smokers had lower levels of folate and flavin mononucleotide than non-smokers. After restoration of euthyroidism, both folate and riboflavin were significantly lower in smokers than non-smokers. Plasma total homocysteine increased according to decreasing quartiles of B-vitamins. For riboflavin, this relation was confined to smokers.

CONCLUSION

Plasma total homocysteine changes according to thyroid status. These changes may be partly attributable to altered folate, cobalamin but also riboflavin status, particularly in smokers.

Influence of smoking on markers of oxidative stress and serum mineral concentrations in teenage girls in Korea

OBJECTIVE

The purpose of this study was to examine the effect of cigarette smoking on serum oxidative damage, antioxidant status, and mineral concentrations in teenage girls.

METHODS

Subjects were randomly chosen from female senior high school students (15-17 y) in a rural community in Korea. Smoker (n = 19) was defined as a person who had smoked 10 or more cigarettes/d continually for at least 1 y while non-smoker (n = 19) was a person who had no previous smoking experience. All individuals in smoker group had serum cotinine concentrations greater than 110 ng/mL, and those in non-smoker group had concentrations of less than 30 ng/mL. Serum oxidative defense enzyme activities, serum antioxidant nutrient concentrations, anthropometric data, and dietary nutrient intakes were evaluated.

RESULTS

Serum selenium glutathione peroxidase, glutathione reductase, and extracellular superoxide dismutase activities were lower in smokers than in non-smokers. Serum ascorbic acid and folate concentrations were lower in smokers than in non-smokers, whereas serum thiobarbituric acid-reactive substances (TBARS) were higher. Serum copper, iron, and magnesium concentrations were similar in the two groups. Serum zinc concentrations were higher in smokers.

CONCLUSIONS

Teenagers with a short smoking history can have evidence of oxidative stress (high serum TBARS and low serum ascorbic acid and folate concentrations) and an impaired oxidant defense system. However, in contrast to common findings in adult smokers, blood pressure was lower in teenage smokers, and hypozincemia and hypercupremia were not observed. Alterations observed in mineral metabolism in adult smokers are probably secondary to chronic diseases associated with long-term smoking.

DNA methylation and diet in cancer

The studies reviewed here investigate the association between folate status and DNA methylation in cancer tissues. We evaluated tissue vitamin levels and global DNA methylation, a biomarker of neoplasia, in normal lung and lung cancer tissues. Lung squamous cell carcinoma tissues exhibited global DNA hypomethylation, with decreased folate and vitamin B-12 concentrations, and increased vitamin C concentrations, relative to matched uninvolved control tissues. Breast cancer tissues also had globally hypomethylated DNA and decreased vitamin B-12 and vitamin C levels, but folate concentrations were elevated in breast cancer tissues. Global DNA methylation status in buccal mucosal cells may reflect global methylation status in lung tissues, because there was a significant association between global DNA methylation in buccal mucosal cells and malignant tissues of the lung, but not between methylation in peripheral leukocytes and lung tissues. We found that global DNA hypomethylation, as assessed by a radiolabeled 5-methylcytosine technique, was associated with susceptibility for development of lung cancer, which is involved in the progression of the disease. DNA methylation was also associated with the development of squamous cell carcinomas in whites but not in blacks. Overall, these studies suggest that global DNA methylation patterns may vary depending on the type of cancer, that tissue vitamin levels are associated with global DNA methylation status and that ethnicity should be considered in studies of DNA methylation.

Cellular vitamins, DNA methylation and cancer risk

The overall goal of this research is to evaluate interactions among cellular vitamin levels and global DNA hypomethylation and the impact of these variables on human cancer risk. Global DNA methylation was determined by two methods: a radiolabeled methyl incorporation (RMI) assay and an immunohistochemical assay using an antibody to 5-methylcytosine (5-MC). The RMI assay is useful for evaluating methylation of DNA in tissue samples, whereas the 5-MC assay clearly reveals DNA methylation in specific types of cells and has minimal day-to-day variability. We have observed significant interactions among cancer-protective vitamins and global DNA methylation at the level of tissues. A significant positive association was observed between global DNA methylation in buccal mucosal cells and malignant tissues, but not between global DNA methylation in peripheral leukocytes and malignant tissues of the lung. These results suggest that changes in global methylation in buccal mucosal cells may reflect changes in tissues at high risk of developing lung cancer. With the antibody technique, we have demonstrated that alterations in global DNA methylation are associated with epigenetic differences in susceptibility for development of lung cancer, which is involved in the progression of the disease. The effect of race on these relationships also is discussed. Significant associations observed between expression of epidermal growth factor receptor and global DNA methylation, as assessed by the 5-MC assay but not by the RMI assay, indicate that evaluation of global methylation and biomarkers in specific types of cells may shed light on the associations between global DNA methylation and other intermediate endpoint biomarkers in the future.

Folate intake, serum homocysteine and methylenetetrahydrofolate reductase (MTHFR) C677T genotype are not associated with oral cancer risk in Puerto Rico

We examined the relationships between folate and methionine intake, serum homocysteine levels (as a biomarker for folate metabolism), and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism genotype and risk of oral cancer in a population-based, case-control study in Puerto Rico. Structured questionnaires were used to collect information on demographic factors, usual adult diet, and tobacco and alcohol use. Oral epithelial cells and blood samples were collected from a subset of subjects. Analyses were conducted by logistic regression, adjusting for age, sex, lifetime smoking and lifetime alcohol intake, with the following numbers of cases/controls, respectively: dietary data (341/521); MTHFR genotype (148/149); and homocysteine (60/90). Although increased folate intake was associated with decreased oral cancer risk [adjusted odds ratio (OR) in highest vs. lowest quartile = 0.6, 95% confidence interval (CI): 0.4, 1.0, P(trend) = 0.05)], this finding was due almost entirely to folate intake from fruit (adjusted OR = 0.4, 95% CI: 0.2, 0.6; P(trend) = 0.0001), whereas other dietary folate sources showed no clear association. Methionine intake and serum homocysteine levels were not associated with oral cancer risk. Subjects with the MTHFR C677T homozygous variant (TT) genotype had a nonsignificantly lower risk, and risk patterns tended to differ by level of folate, methionine, alcohol intake and smoking, although the power to detect significant associations in subgroups of these variables was low. Risks for oral cancer are not folate specific; preventive recommendations for this disease should emphasize the importance of a healthy diet, including substantial intake of fruits.

Smoking cessation, but not smoking reduction, reduces plasma homocysteine levels

BACKGROUND

Cigarette smoking has been associated with increased plasma homocysteine levels. Although hyperhomocysteinemia may mediate some of the adverse cardiovascular consequences of smoking cigarettes, the effects of smoking cessation and smoking reduction on homocysteine levels have not been evaluated previously.

HYPOTHESIS

The purpose of this study was to determine the effects of smoking cessation and smoking reduction on plasma homocysteine levels.

METHODS

Fifty-one healthy subjects who smoked 35.9 +/- 6.4 cigarettes daily were randomized to continue smoking, reduce smoking to 4-8 cigarettes daily, or to stop smoking. A nicotine inhaler and individualized counseling were provided as aids to smoking cessation.

RESULTS

In subjects who quit smoking, homocysteine levels decreased by 11.6%, from 8.58 +/- 2.31 to 7.53 +/- 2.26 micromol/l (p = 0.013). Significant changes in homocysteine levels were not observed in subjects who reduced smoking or continued to smoke.

CONCLUSION

A "harm reduction" strategy of reducing cigarette use may not be sufficient for reducing the vascular risk associated with smoking cigarettes.

Localized folate and vitamin B-12 deficiency in squamous cell lung cancer is associated with global DNA hypomethylation

We measured the concentrations of folate and vitamin B-12 in paired tissue samples of squamous cell cancer (SCC) and adjacent grossly normal-appearing uninvolved bronchial mucosa (from which SCC developed and also "at risk" of developing SCC) of the lung in 12 subjects to determine the involvement of these vitamins in 1) lung carcinogenesis and 2) global DNA methylation. The folate concentrations were significantly lower in SCCs than in uninvolved tissues (p = 0.03). The vitamin B-12 concentrations were also significantly lower in SCCs than in uninvolved tissues (p = 0.02). The radiolabeled methyl incorporation (inversely related to the degree of in vivo DNA methylation) was significantly higher in SCCs than in uninvolved tissues (p < 0.0001). The correlation between folate and radiolabeled methyl incorporation was inverse and statistically significant in SCCs (p = 0.03). The correlation between vitamin B-12 and radiolabeled methyl incorporation also was inverse and statistically significant in SCCs (p = 0.009). The relationship between tissue vitamin B-12 and DNA methylation was minimal in uninvolved tissues. The relationship between folate and DNA methylation, however, was inverse in uninvolved tissues. In the multiple regression models that included both vitamins, only folate was inversely associated with radiolabeled methyl incorporation in uninvolved and cancerous tissues. These results suggested that folate might be the limiting vitamin for proper DNA methylation in SCC as well as in tissues at risk of developing SCC. Several possible mechanisms of folate deficiency, including inactivation of the vitamin by exposure to carcinogens of cigarette smoke and underexpression or absence of folate receptor in SCCs and associated premalignant lesions, are discussed in light of these findings.

Association between B vitamin intake and plasma homocysteine concentration in the general Dutch population aged 20-65 y

BACKGROUND

An elevated plasma total homocysteine (tHcy) concentration is associated with an increased risk of cardiovascular diseases. Folate, riboflavin, vitamin B-6, and vitamin B-12 are essential in homocysteine metabolism.

OBJECTIVE

The objective was to describe the association between dietary intakes of folate, riboflavin, vitamin B-6, and vitamin B-12 and the nonfasting plasma tHcy concentration.

DESIGN

A random sample of 2435 men and women aged 20-65 y from a population-based Dutch cohort examined in 1993-1996 was analyzed cross-sectionally.

RESULTS

Univariately, intakes of all B vitamins were inversely related to the plasma tHcy concentration. In multivariate models, only folate intake remained inversely associated with the plasma tHcy concentration. Mean plasma tHcy concentrations (adjusted for intakes of riboflavin, vitamin B-6, vitamin B-12, and methionine and for age, smoking, and alcohol consumption) in men with low (first quintile: 161 microg/d) and high (fifth quintile: 254 microg/d) folate intakes were 15.4 and 13.2 micromol/L, respectively; in women, plasma tHcy concentrations were 13.7 and 12.4 micromol/L at folate intakes of 160 and 262 microg/d, respectively. In men, the difference in the mean plasma tHcy concentration between men with low and high folate intakes was greater in smokers than in nonsmokers (2.8 compared with 1.6 micromol/L) and greater in nondrinkers than in drinkers of >2 alcoholic drinks/d (3.5 compared with 1.4 micromol/L). In women, the association between folate intake and plasma tHcy was not modified by smoking or alcohol consumption.

CONCLUSIONS

In this Dutch population, folate was the only B vitamin independently inversely associated with the plasma tHcy concentration. Changing dietary habits may substantially influence the plasma tHcy concentration in the general population.

Hypothesis for temporal displacement of metabolic and neuronal accommodation in smoking addiction

Using the overlapping criteria of (1) current smoking status and (2) homeostatic accommodation of smoking, the categories of nonsmoker, beginning smoker, smoker, and quitting smoker are structured into a cyclic representation of smoking addiction. This cyclic representation reveals that elimination of homeostatic accommodation of smoking is a critical success factor to the process of becoming a nonsmoker, while the act of stopping smoking is necessary yet insufficient to the success of that process. Homeostatic accommodation is described as having two components: metabolic and neuronal. A hypothesis for temporal displacement of metabolic and neuronal accommodation is presented to explain the behavior of "chippers" (occasional smokers) and adolescent smokers. Recommendations are made for research on the rates of development and dissipation of metabolic and neuronal accommodation of smoking, and for the development of a bimodal therapy that addresses both metabolic and neuronal accommodation and reduces relapse for quitting smokers.

Folate intake, alcohol consumption, cigarette smoking, and risk of colorectal adenomas

BACKGROUND

Recent evidence suggests that folic acid (and derivatives) could contribute to the protective effect of fruits and vegetables against the risk of large-bowel cancer. Other evidence indicates that alcohol drinking and cigarette smoking may impair the biologic actions of folate. We used data from an adenoma prevention trial to investigate the occurrence of colorectal adenomas (possible precursors of colorectal cancer) in association with folate intake, alcohol consumption, and cigarette smoking.

METHODS

Patients with at least one recent large-bowel adenoma were followed with colonoscopy 1 year and 4 years after their qualifying colon examinations. Adenomas detected after the year 1 examination were used as end points. A food-frequency questionnaire was administered at study entry and at study completion; nutrient intake at study entry was used in this analysis. All statistical tests were two-sided.

RESULTS

After adjustment for caloric intake, dietary folate had a significant protective association with the risk of recurrence of large-bowel adenoma (P for trend = .04). However, this inverse association was attenuated by further adjustment for intake of dietary fiber and fat. Use of folate supplements was not associated with a reduction in risk. Alcohol intake (seven or more drinks/week) was associated with increased risk (odds ratio = 2.04; 95% confidence interval = 1.28-3.26). Cigarette smoking, even smoking for long duration, was not related to adenoma recurrence.

CONCLUSIONS

These data provide only modest support for previous findings suggesting beneficial effects of folate on colorectal adenoma risk. We find no evidence that cigarette smoking increases risk. These findings do suggest a substantial increase in risk with alcohol consumption.

Fish oil may be an antidote for the cardiovascular risk of smoking

The fact that the cardiovascular risk of ex-smokers approximates that of non-smokers after two years of abstinence, implies that accelerated atherogenesis is not the chief mechanism of smoking-related heart disease. Indeed, smoking or nicotine have adverse effects on blood rheology, thrombotic risk, coronary blood flow, and risk for arrhythmias. Omega-3-rich fish oils can be expected to correct or compensate for a remarkable number of the adverse impacts of smoking/nicotine: increased plasma fibrinogen, decreased erythrocyte distensibility, increased plasma and blood viscosity, increased platelet aggregability, increased plasminogen activator inhibitor levels, vasoconstriction of the coronary bed, reduced fibrillation threshold, increased triglycerides, reduced high-density lipoprotein cholesterol, and increased production of superoxide by phagocytes. Smokers who cannot overcome their addiction should be encouraged to substitute nicotine aerosols/gum for tobacco and advised to use supplementary fish oil and other cardioprotective nutrients.

Serum vitamins' status in oral leucoplakias--a preliminary study

Vitamins, such as A, beta carotene, C, E, B12 and folate, are the micronutrients with the strongest evidence of having a link to cancer prevention and control. Deficiency of these vitamins at the dietary, systemic or mucosal level will interact with tobacco use and increase the risk of oral precancerous lesions. The objective of this study was to (1) establish the baseline circulating levels of these vitamins in our normal population with and without tobacco use and (2) compare these levels with the values obtained in cases of oral leucoplakias. 50 normal controls with 25 each in chewers and non-chewers, matched for age and sex, were selected. 50 cases of oral leucoplakias (clinically detectable white patches) from the field constituted the study group. Simultaneous measurement of serum vitamin B12 and folate were carried out by radioassay. The other serum vitamins were estimated spectrophotometrically. Except for serum vitamin E, all the other serum vitamin levels were significantly decreased in oral leucoplakias compared to the controls. Cancer chemopreventive agents acting as inhibitors of both initiation and promotion, as analysed in our population, is promising for further intervention trials.

Osmotic and other properties of isolated human cheek epithelial cells

This study describes some biological properties of human cheek (buccal epithelial) cells, isolated by mouth wash. Yields ranged from 6.5 to 20.6 x 10(6) cells, with a mean (+/- SE) of 12.2 +/- 4.2 x 10(6) cells, which gave 0.55 +/- 0.01 x 10(6) cells/mg protein. Vital stain exclusion was similar in cells isolated in either water (89 +/- 2%) or 250 mM sucrose (87 +/- 3%). From our measurements of cell volume and electrolyte content, we estimated intracellular Na+ and K+ concentrations to be between 0.3-0.5 and 7.4-13.0 mM, respectively. In 22 adult subjects, basal, prickle, intermediate, and superficial cells represented 0.3 +/- 1.4, 51 +/- 2.4, 26 +/- 0.9, and 22.7 +/- 1.8%, respectively, of the total sample. Cheek cells exhibited a low endogenous rate of oxygen consumption, which was stimulated by glucose or succinate and inhibited by KCN or NaF. Cheek cells were osmotically stable in a wide range of media, including water. However, they exhibited shrinkage and collapse in hypertonic media, particularly polyethylene glycol.

Folate and cancer: A review of the literature

Folate, a water-soluble vitamin, part of the vitamin B complex, plays an important role in methylation reactions and DNA/RNA synthesis. This review examines the experimental and epidemiological evidence for the association between folate status and risk of cancer. Data have accumulated indicating that low folate status may promote carcinogenesis. Low folate levels are associated with cytogenetic abnormalities in vivo and in vitro. Findings from animal studies are conflicting and suggest that the effect of folate on neoplasia depends on factors such as the animal and tumor model, the type, timing, dose, and length of application of carcinogen, the stage of carcinogenesis, and the level and form of folate administered. Epidemiological studies examined the association between folate and cancer of the cervix, colorectum, lung, esophagus, and brain and suggest that low folate status may play an important role early in the neoplastic process. The potential for inhibition of precursor lesions in the cervix and colorectum, namely, cervical intraepithelial neoplasia and adenomatous polyps, respectively, is of particular interest. Additional research designed to clarify the role of folate in carcinogenesis is warranted.

Hyperhomocysteinemia in patients operated for lower extremity ischaemia below the age of 50--effect of smoking and extent of disease

Moderate hyperhomocysteinemia may be a risk factor for atherosclerotic peripheral vascular disease (PVD). In order to develop PVD at an early age risk factors are more strongly expressed and hyperhomocysteinemia may be one such factor. Homocysteine is derived from methionine and is metabolised by cystathionine-synthase to cystathionine or remethylated to methionine. Cystathionine-synthase activity is dependent on vitamin B6 while the remethylation of homocysteine is dependent on vitamin B12 and folate. The present study analyses homocysteine in patients operated on for lower extremity ischaemia before the age of 50. Homocysteine before and after loading with methionine, vitamin B6, B12 and folate were measured at follow-up. The patients were compared to age- and sex-matched controls. Significantly more patients than controls had hyperhomocysteinemia, 16/58 vs. 4/65, defined as fasting total homocysteine above 18.6 mumol/l. Loading with methionine did not further discriminate between patients and controls. Smoking patients had higher levels of homocysteine than non-smoking patients or smoking and non-smoking controls. Smoking patients also had lower levels of vitamin B6. When comparing patients with suprainguinal, infrainguinal and multilevel disease the highest homocysteine levels were seen in the latter group. Also, in this group smoking patients had higher homocysteine levels. Multivariate analysis revealed that homocysteine was associated with low levels of vitamin B12, folate and smoking. Smoking therefore seems to be connected to increased homocysteine levels in patients with early development of atherosclerosis, partly explained by decreased levels of B6, B12 and folate.