Relationship of smoking and smoking cessation with number of teeth present: JPHC Oral Health Study*.

BACKGROUND: Smoking is associated with the number of teeth. The purpose of this study was to determine the relationship of number of teeth with smoking and smoking cessation. METHODS: Subjects included 547 males aged between 55 and 75 years. Oral examinations were conducted in 2005. Smoking status information was collected from questionnaire surveys conducted in 1990, 1995, 2000, and 2005. The relationship between having more than eight missing teeth and smoking status was estimated with adjusted odds ratio. RESULTS: Comparing with never smokers, odds ratios of having more than eight missing teeth among current and former smokers were 1.96 and 1.86, respectively. The odds ratios in those who had stopped smoking for

Cigarette smoking, CYP1A1 MspI and GSTM1 genotypes, and colorectal adenomas.

Cigarette smoking has been related to increased risk of colorectal adenomas, but the underlying mechanisms are unknown. Genetic polymorphisms are known for enzymes involved in the activation of polycyclic aromatic hydrocarbons and other tobacco-related carcinogens. Polycyclic aromatic hydrocarbons are activated by cytochrome P4501A1 (CYP1A1) and detoxified by glutathione S-transferases. We investigated the relation of CYP1A1 MspI and GSTM1 genotypes to the risk of colorectal adenomas with special reference to interaction with cigarette smoking among 205 cases of colorectal adenomas and 220 controls with normal total colonoscopy in a male Japanese population. Cigarette smoking was strongly associated with increased risk of colorectal adenomas. Overall, neither the CYP1A1 MspI genotype nor the GSTM1 genotype was related to colorectal adenomas. A significant trend for increased risk of colorectal adenomas associated with smoking was observed for each of the CYP1A1 MspI genotypes, and the increasing trends did not differ by MspI genotype. The positive association between smoking and colorectal adenomas did not vary much with GSTM1 genotypes. Among former and current smokers, adenoma risk did not differ according to the combination of CYP1A1 MspI and GSTM1 genotypes. CYP1A1 MspI and GSTM1 genotypes do not seem to modify the risk of colorectal adenomas associated with cigarette smoking.

Methylenetetrahydrofolate reductase polymorphism and risk of colorectal adenomas.

A homozygous mutation at bp 677 in the gene for the methylenetetrahydrofolate reductase (MTHFR) was previously shown to be associated with a decreased risk of colorectal cancer. We examined the relation between the MTHFR genetic polymorphism and risk of colorectal adenoma in Japanese men using 205 cases of colorectal adenomas and 220 controls of normal total colonoscopy. The homozygous mutation was not measurably associated with colorectal adenomas. The findings corroborate the lack of an association between the MTHFR genotype and colorectal adenomas, but do not deny the possibility that the genotype may be involved in the late stage of colorectal carcinogenesis.

Apolipoprotein E genotype, serum lipids, and colorectal adenomas in Japanese men.

We examined the relation of serum lipids and apolipoprotein E genotype to colorectal adenomas among 205 cases and 220 controls with normal colonoscopy in Japanese men. With adjustment for body mass index, cigarette smoking, alcohol use, and other covaiates, odds ratios of proximal and distal adenomas associated with the presence of an allele varepsilon4 were 0.59 (95% confidence interval 0.23-1.45) and 0.99 (0.50-1.98), respectively. While serum total and LDL cholesterol were unrelated to both proximal and distal adenomas, serum triglycerides were positively related to distal adenomas. The findings suggest that altered lipid metabolism may be differentially associated with tumorigenesis in the proximal and distal colorectum.

Glutathione S-transferase polymorphisms and risk of colorectal adenomas.

Glutathione S-transferases (GSTs) are a superfamily of detoxification enzymes that may play an important role in human carcinogenesis. While the genetic polymorphisms GSTM1 and GSTT1 have drawn particular interest in relation to cancer susceptibility, previous studies of colorectal cancer are inconsistent regarding their role. We examined the relation between GSTM1 and GSTT1 genotypes combined and colorectal adenomas, and the interaction with cigarette smoking among 205 cases of colorectal adenomas and 220 controls with normal total colonoscopy in Japanese men. Neither GSTM1 nor GSTT1 was related to colorectal adenomas, nor were the null genotypes of GSTM1 and GSTT1 combined. The lack of an association with GSTM1 and GSTT1 genotypes combined persisted even when the analysis was done separately for proximal and distal colorectal adenomas. A three- to fivefold significant increase in the odds of colorectal adenomas was observed among men with a high exposure to cigarette smoking across the genotype groups, and a statistically significant increasing trend was noted within each genotype group. The present findings do not support the role for GSTM1 and GSTT1 genotypes in the development of colorectal adenomas.

Alveolar bone loss associated with glucose tolerance in Japanese men.

AIMS: Type 2 diabetes is known to affect alveolar bone loss (ABL). The purpose of this study was to examine whether impaired glucose tolerance (IGT) is associated with ABL, as is diabetes. METHODS: A case-control study was performed with 664 Japanese men aged 46-57 years. Panoramic radiographs revealed 513 severe ABL cases, 22 moderate ABL cases, and 129 controls with good alveolar bone. Diabetes status was classified into normal glucose tolerance (NGT), impaired fasting glucose (IFG), IGT, and newly diagnosed diabetes according to the fasting plasma glucose and 75-g oral glucose tolerance test (OGTT). Diabetes under treatment was excluded. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained from ordinal logistic regression analysis. Statistical adjustment was made for total cholesterol, HDL-cholesterol, triglyceride, rank in the Self Defence Forces (SDF), cigarette-years, alcohol use, body mass index, previous 10 years' brushing habits and instrument use other than toothbrush, and history of periodontal treatment. RESULTS: A significant, approximately three-fold increase in the crude OR (crude OR=3.28; 95% CI=1.16-9.27) and non-significant 2.6-fold increase in the adjusted OR (adjusted OR=2.55; 95% CI=0.86, 7.54) of ABL was observed among men with newly diagnosed Type 2 diabetes compared with the reference group (NGT combined with IFG). However, there was no association between IGT and ABL (adjusted OR=0.99; 95% CI=0.59,1.64). CONCLUSIONS: Type 2 diabetes, but not IGT, was positively associated with ABL. Preventive maintenance against periodontitis is important in middle-aged men with diabetes.

Filter cigarette smoking and lung cancer risk; a hospital-based case--control study in Japan.

Recent changes in the histology of lung cancer, namely a relative increase of adenocarcinoma compared to squamous cell carcinoma, might be due to a temporal shift from nonfilter to filter cigarettes. To investigate the association between type of cigarette and lung cancer by histological type, we conducted a case-control study in Japan, comprising 356 histologically confirmed lung cancer cases and 162 controls of male current smokers, who provided complete smoking histories. Overall, logistic regression analysis after controlling for age and prefecture revealed decreased risk, as shown by adjusted odds ratios, for both squamous cell carcinoma and adenocarcinoma among lifelong filter-exclusive smokers as compared to nonfilter or mixed smokers. This decrease was greater for squamous cell carcinoma than for adenocarcinoma. Among men under 54 years, filter-exclusive smokers displayed increased risk of adenocarcinoma, but decreased risk of squamous cell carcinoma. The recent shift in histology from squamous cell carcinoma to adenocarcinoma, particularly among younger smokers, might be due to changes in cigarette type. However, among subjects aged 65 years or more, no differences in histological type appeared related to type of cigarette smoked, implying that other factors are associated with increases in adenocarcinoma among older Japanese population.

Obesity, weight gain and risk of colon adenomas in Japanese men.

Obesity has been related to increased risk of colon cancer or adenomas, but the epidemiologic findings are not entirely consistent. We examined the relation of not only body mass index (BMI) but also waist-to-hip ratio (WHR) and weight gain to colon adenoma risk in men who received a preretirement health examination at the Japan Self Defense Forces (SDF) Fukuoka and Kumamoto Hospitals during the period from 1995 to 1996. In the series of 803 men at age 47-55 years, 189 cases of colon adenomas and 226 controls with normal total colonoscopy were identified. Weight at 10 years before was ascertained by referring to the recorded data. After allowance for hospital, rank in the SDF, smoking and alcohol use, weight gain over the past 10 years was significantly associated with increased risk of colon adenomas (odds ratio for > or = 6 kg versus < or =-2 kg = 2.2; 95% confidence interval 1.0-4.8). High BMI and high WHR were each associated with increased risk, but only WHR was related to the risk independently of weight gain. In particular, weight gain accompanied with a high WHR was associated with a significant increase in the risk. Men with high physical activity tended to have lower risk. Associations with obesity-related variables and physical activity were not materially differential as regards the location and size of adenoma. The findings indicate that weight gain in middle age leading to abdominal obesity increases the risk of colon adenomas, and consequently of colon cancer.