日本における魚摂取と前立腺癌罹患に関する前向きコホート研究  [in Japanese] FISH INTAKE AND THE RISK OF PROSTATE CANCER IN JAPAN : A PROSPECTIVE COHORT STUDY  [in Japanese]

(目的)魚摂取と前立腺癌罹患リスク低下との関連に関する従来の前向きコホート研究の結果は一致しておらず,魚摂取の多い国での検討は少ない.本研究の目的は日本人を対象に,魚摂取と前立腺癌罹患リスクとの関連について検討することである.(対象と方法)宮城県大崎保健所管内に居住する40〜79歳の国民健康保険に加入している男性全員を対象に,1994年10月から12月に自記式質問票を配布した.回収率は94% (24,895名)であった.質問票の魚摂取頻度より魚摂取量を算出し,対象者を四分位に分類した.魚摂取量最小四分位群を基準として,他群の前立腺癌罹患のハザード比(HR),95%信頼区間(95%CI)をCox比例ハザードモデルにて算出した.(結果)7年間の追跡期間中,95例の前立腺癌罹患を確認した.前立腺癌罹患の多変量補正HR(95%CI)は魚摂取量の最も多い群で0.72 (0.40〜1.33)(傾向性のP値=0.23)であった.70歳未満では関連がみられなかったが,70歳以上の多変量補正HR(95%CI)は魚摂取量の最も多い群で0.44 (0.18〜1.11)(傾向性のP値=0.08)であった.(結論)40〜69歳では関連は見られなかった.一方,70歳以上ではリスクが低下する傾向が見られたが,有意ではなかった.

(Objective) Fish intake may reduce the risk of prostate cancer. However, the results of previous prospective cohort studies have been inconsistent, and almost all have been undertaken in Western countries, where total fish intake is low. We therefore investigated the association between fish intake and the risk of prostate cancer in a prospective cohort study in Japan. (Participants and methods) We delivered a self-administered questionnaire including items on dietary intake (40-item food frequency questionnaire [FFQ]), and various lifestyle habits, between October and December 1994 to all male National Health Insurance (NHI) beneficiaries aged 40-79 years in Japan. Usable questionnaires were returned from 24, 895 (94%) of the participants. We divided the participants into quartiles based on their self-reported fish intake. We used the Cox proportional hazards model to estimate the hazard ratio (HR) and 95% confidence interval (CI) of prostate cancer incidence according to fish intake, after adjustment for potential confounders. (Results) We identified 95 prostate cancer cases during 7 years of follow-up, to the end of December 2001. An inverse association was observed between fish intake and the risk of prostate cancer. The multivariate HRs (95%CI) of prostate cancer across increasing quartiles of fish intake were 1.00, 0.92 (0.48-1.76), 0.73 (0.42-1.28), and 0.72 (0.40-1.33) (P for trend=0.23). Among participants aged 40-69 years, the multivariate HRs (95%CI) of prostate cancer across increasing quartiles of fish intake were 1.00, 1.26 (0.51-3.11), 0.86 (0.38-1.94), and 1.01 (0.43-2.34) (P for trend=0.83). On the other hand, among participants aged 70 years or older, the corresponding multivariate HRs (95%CI) were1.00, 0.63 (0.23-1.69), 0.60 (0.27-1.30), and 0.44 (0.18-1.11) (P for trend=0.08). (Conclusions) The risk of prostate cancer tended to decrease among those aged 70 years or older although it was not significant. The relation was not seen in those aged 40-69 years old.