Serum concentrations of fatty acids and colorectal adenoma risk: a case-control study in Japan.

BACKGROUND: Epidemiologic studies of n-3 fatty acids (FAs) and risk of colorectal cancer have generated inconsistent results, and relations with precursor colorectal adenomas (CRA) have not been evaluated in detail. We here focused on possible associations of serum FAs with CRA in the Japanese population. METHODS: We conducted a case-control study of 203 asymptomatic CRA cases (148 men, 55 women) and 179 healthy controls (67 men, 112 women) during 1997-2003 in Nagoya, Japan. Baseline information was obtained using a lifestyle questionnaire and serum FA levels were measured by gas chromatography. RESULTS: A non-significant inverse association with CRA was observed for eicosapentaenoic acid (EPA) among women. Moreover, the concentrations of docosahexaenoeic acid (DHA), a major component of n-3 highly-unsaturated FAs (HUFAs), were significantly lower in cases in both sexes. In addition, serum concentrations of total FAs, saturated FAs (SFAs) and mono-unsaturated FAs (MUFAs) had strong positive links with CRA risk. In contrast, arachidonic acid (AA) and DHA were inversely related, with 66% and 59% risk reduction, respectively. Ratios of SFAs/n-3 PUFAs and SFAs/n-3 HUFAs exhibited significant positive relations with CRA risk but there was no clear link with n-6 PUFAs/n-3 PUFAs. CONCLUSIONS: Our findings suggest a promoting influence of SFAs and MUFAs along with a protective effect of DHA on CRA risk. However, further research is needed to investigate the observed discrepancy with the generally accepted roles of the AA cascade in carcinogenesis.

Host and environmental factors for gastric cancer in Babol, the Caspian Sea Coast, Iran.

To clarify host and environmental factors for gastric carcinogenesis, we obtained information about gastric cancer mortality in Babol, in the North of Iran, and recruited 130 participants aged 30-80 years from the general population of Babol in 2004. A urea breath test, assessment of IgG antibodies to Helicobacter pylori, a pepsinogen test, a marker of chronic atrophic gastritis, and determination of urinary excretions of sodium and potassium were performed. Diet and lifestyle information was also obtained using a questionnaire. The stomach cancer mortality rate for men in Babol (38.2/10(5)) was found to be somewhat lower than that for Japanese men (45.1/10(5)), while the mortality for women (26.9/10(5)) was higher than for Japanese women (20.9/10(5)). Positive rates for the urea breath test were 77.5 and 81.8% for Iranian men and women, respectively. Helicobacter pylori IgG antibodies were present in 68.7 and 73.7% of Iranian men and women, respectively, both values being marginally higher than for Japanese. We also found 51.0 and 52.8% to be positive for a pepsinogen test, significantly higher than the Japanese values. Urinary excretions of salt and potassium in this population appeared approximately the same as the consumption in Japanese. The elevated gastric cancer mortality in both men and women in Babol seems, by and large, to be related to higher H. pylori infection rates and prevalence of chronic atrophic gastritis. Certain factors, including H. pylori DNA diversity, host factors and their interactions, together with the level of medical practice, prevalence of and access to secondary prevention of stomach cancer, may also be associated with the relatively high mortality.