Validity and reproducibility of the PC-assisted dietary interview used in the Fukuoka Colorectal Cancer Study.

Epidemiologic studies based on quantitative estimation of food and nutrient intake have been limited in Japan. We evaluated validity and reproducibility of a personal computer (PC)-assisted dietary interview used in the Fukuoka Colorectal Cancer Study. The subjects were 28 participants as controls in a population-based case-control study. Four 7-day diet records were kept during a period from July 2001 to May 2002, and the PC-assisted dietary interview was administered before and after the diet records (May to July 2001 and July to September 2002). Intakes of total energy, 26 nutrients, and 19 food groups were estimated. Of 26 Pearson correlation coefficients for energy-adjusted nutrients, 18 for the first interview and 19 for the second interview were 0.40 or greater, with the highest correlation for saturated fat in the first interview (0.72) and vitamin C in the second interview (0.60). Validity scores were fairly high for most of the food groups with an exceptionally low correlation for potatoes (0.19 for the first and 0.13 for the second interview). Reproducibility was good for most nutrients and foods; but low correlation was noted for Vitamin D and nuts/seeds. Reproducibility was modest for fish and fish products, beef and pork, and processed meat. The PC-assisted dietary interview was fairly valid and reproducible regarding most of the nutrients and food groups. Validity and reproducibility of meat and fish intakes were probably attenuated because of the episode of bovine spongiform encephalopathy in September 2001.

Impact of C-reactive protein on disease risk and its relation to dietary factors.

C-reactive protein (CRP) is one of the acute-phase proteins in inflammation and CRP serum concentrations are therefore of interest. Data for high-sensitivity CRP (hs-CRP) with a low detection limit of approximately 0.04 mg/L have become available over the past decade and research has shown a link between high concentrations of hs-CRP and obesity as well as smoking. Expanded adipose tissue is in fact known to secrete proinflammatory cytokines which enhance hepatic synthesis of CRP. Moderate alcohol consumption and high physical activity have been associated with low levels of hs-CRP, but the evidence in these cases is not conclusive. It has been suggested that hs-CRP is an independent marker of the risk of cardiovascular disease, but the predictive capacity remains controversial. However, many prospective studies have observed increased risk of type 2 diabetes mellitus associated with high concentrations of hs-CRP, independent of obesity and other cardiovascular risk factors. On the other hand, no measurable increase in the risk associated with high levels of hs-CRP was observed with multivariate adjustment in several studies. A number of authors have reported that high concentrations of hs-CRP are associated with increased risks of colorectal and other cancers, but the findings again are inconsistent. Diet and hs-CRP are also of increasing research interest. High intakes of carotenoids and vitamin C, but not of vitamin E, seem to decrease the level of circulating hs-CRP. In addition, high consumption of vegetables and fruit are associated with lower levels of circulating hs-CRP, perhaps by exerting anti-inflammatory effects. Both mechanistic and epidemiologic studies regarding dietary factors and low-grade inflammation are necessary to add to our knowledge of dietary influence on chronic disease development.

What do cancer registry and household expenditure data in Japan tell us about variation in tumour burden ?

Data from the total of six Japanese Cancer Registries presently reporting to Cancer Incidence in Five Continents demonstrate marked variation in relative prevalence of cancers at particular sites, despite the genetic homogeneity of the Japanese population. Thus either major differences in registry procedures or local environment must be playing an important role and since the variation is clearly changing with time, the former must be considered likely. Over the last 25 year period, incidence rates for the esophagus have been generally increasing in Japan, except in Miyagi where they have been persistently high. Stomach cancer rates are on the decrease, although the trend is not so clear in Yamagata and Hiroshima, while colon and rectal cancers have both demonstrated consistent increment throughout the period surveyed, with a remarkable correlation between the two sites evident on cross-registry comparisons. Continued increases have also been apparent in lung, kidney, urinary bladder and prostate cancers in males and in breast, endometrium and thyroid neoplasms in females. Cervical cancer, in contrast, is decreasing, although a plateau may now have been reached in Miyagi. In the hepatopancreatic axis, patterns have generally showed elevation followed by a recent reduction, although without correlations among liver, gallbladder and pancreas rates at the cross-registry level. Common lifestyle factors may to some extent underly the increases seen in colon, breast, urinary bladder and thyroid incidence rates, given the significant relations apparent for these in the latest data across registries. Whether analysis of variation in dietary intake and exposure to other risk factors, for example using data for household expenditure, may provide clues to explaining the variation apparent across Japan is a question warranting further consideration. If so an expanded role for the cancer registry could well be envisaged.

The metabolic syndrome is associated with increased risk of colorectal adenoma development: the Self-Defense Forces health study.

The metabolic syndrome, a cluster of metabolic abnormalities linked to insulin resistance, has attracted much interest as a risk factor for cardiovascular disease and type 2 diabetes. Hyperinsulinemia is also a postulated biological risk factor for colorectal carcinogenesis. We therefore here examined the relation between the metabolic syndrome and colorectal adenoma development. The study subjects were 756 cases of colorectal adenoma and 1751 controls with no polyps who underwent total colonoscopy during the period January 1995 to March 2002 at two Self Defense Forces (SDF) hospitals in Japan. The metabolic syndrome was defined with reference to abdominal obesity in combination with any two of the following conditions: elevated triglycerides (150 mg/dL); lowered HDL cholesterol (<40 mg/dL); elevated blood pressure (systolic blood pressure 130 mmHg and/or diastolic blood pressure 85 mmHg); and raised fasting glucose (110 mg/dL). Abdominal obesity was defined as a waist circumference of 85 cm or more(Japanese criterion) or 90 cm (Asian criterion). Statistical adjustment was made for age, hospital, and rank in the SDF. The metabolic syndrome was found to be associated with a moderately increased risk of colorectal adenomas whether either of the Japanese and Asian criteria was used; adjusted odds ratios with the Japanese and Asian criteria were 1.38 (95% confidence interval [CI] 1.13-1.69) and 1.48 (95% CI 1.13-1.93), respectively. Increased risk was more evident for proximal than distal colon or rectal adenomas, and was almost exclusively observed for large lesions (5 mm in diameter). Thus the metabolic syndrome appears to be an important entity with regard to the prevention of colorectal cancer, as well as cardiovascular disease and type 2 diabetes.

Comparison of Japanese, American-Whites and African-Americans--pointers to risk factors to underlying distribution of tumours in the colorectum.

Relative incidence rates for colon and rectal cancer vary greatly between populations in the world. While Japanese have historically had low prevalence, immigration to the United States has now resulted in equal if not higher rates than in Caucasian- or African-Americans. Furthermore, recent data from some population-based registries in Japan itself are also pointing to particularly high susceptibility. Of particular interest is the fact that Japanese in both the home country and the US in fact have far higher rates for rectal cancer than the other two ethnic groups. An intriguing question is whether they might also demonstrate variation from Caucasian- and African-Americans in the relative incidence rates for proximal and distal colon cancers, given the clear differences in risk factors like diabetes, physical exercise, smoking, alcohol consumption, meat and fish intake and calcium exposure which have been shown to operate in these two sites. A comprehensive epidemiological research exercise is here proposed to elucidate ethnic variation in colorectal cancer development, based on cross-cancer registry descriptive and case control approaches. It is envisaged that additional emphasis on screened populations should further provide important insights into causal factors and how primary and secondary prevention efforts can be optimized.

A case-control study of colorectal cancer in relation to lifestyle factors and genetic polymorphisms: design and conduct of the Fukuoka colorectal cancer study.

A case-control study was designed to elucidate roles of dietary and other behavioral influences, in combination with genetic susceptibility factors (genetic polymorphisms), in colorectal carcinogenesis. Both cases and controls were residents in Fukuoka City and three adjacent areas. Cases were patients undergoing surgery for a first diagnosis of colorectal cancer at 8 hospitals in the study area, and controls were randomly selected in the community by frequency-matching with respect to the expected distribution by sex, age (10-year class), and residence. Dietary and other lifestyle factors were ascertained by in-person interview, and venous blood was obtained for genotyping and possible biochemical measurements. The cases were interviewed at each hospital during the period from 2000 to 2003, and controls were surveyed during the period from 2001 to 2002. A total of 840 cases of colorectal cancer and 833 controls were interviewed with participation rates of 80% for the cases and 60% for the controls. Informed consent to genotyping was obtained from 685 cases and 778 controls. Further details of the design and conduct are described with respect to methodological aspects.