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.
Ghadimi
Reza
R
Department of Public Health, Nagoya City University Graduate School of Medical Sciences Nagoya, Japan.
Kuriki
Kiyonori
K
Tsuge
Shinji
S
Takeda
Emiru
E
Imaeda
Nahomi
N
Suzuki
Sadao
S
Sawai
Asuka
A
Takekuma
Kiyoshi
K
Hosono
Akihiro
A
Tokudome
Yuko
Y
Goto
Chiho
C
Esfandiary
Imaneh
I
Nomura
Hisashi
H
Tokudome
Shinkan
S
D000230:Adenocarcinoma / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control; D000236:Adenoma / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control; D000328:Adult; D000368:Aged; D016718:Arachidonic Acid / Q000008:administration & dosage; D016022:Case-Control Studies; D002849:Chromatography, Gas; D015179:Colorectal Neoplasms / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control; D004435:Eating; D005227:Fatty Acids / Q000097:blood*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D017747:Seafood; D011795:Surveys and Questionnaires
D005227:Fatty Acids; D016718:Arachidonic Acid