本帖最後由 lsc0019 於 2009-5-18 09:06 編輯
作者：Laurie Barclay, MD
出處：WebMD醫學新聞
May 5, 2009 — 根據一項發表於4月27日內科學誌的前瞻性研究結果顯示，結合五種可修飾生活型態因子的指標，這個指標的高、低分可以預測發展成胰臟癌較低的風險。
馬里蘭班賽斯達國家衛生研究院國家癌症機構的Li Jiao醫師與其同事寫到，吸菸、喝酒、飲食、身體質量指數（[BMI]以公斤體重除以公尺身高）以及運動量，與胰臟癌之間的關聯性已經被獨立的研究過；我們發表一個健康型態指數來研究上述因子之共同作用對胰臟癌風險的影響。
這項研究收納了450,416位國家衛生研究院健康AARP飲食與健康研究的受試者，這些受試者的年齡介於50至71歲，他們在1995至1996年之間完成了試驗前的飲食頻次問卷，問卷內容包括飲食與生活型態的資訊，並且接受研究者追蹤到2003年12月31日；在後續追蹤期間，有1,057位胰臟癌病例被確認出來。
對每位受試者來說，以五項可修飾的生活型態因子來打分數，根據目前的流行病學證據，從不健康的（0分）到健康的（1分）。有下列的狀況則各得一分：沒有吸菸、有限制地飲用酒類、遵從地中海式飲食、身體質量指數（≧18與< 25 kg/m2），以及規律的運動。將這些因素的得分加在一起計算出總分（0~5分）。發生胰臟癌的相對風險以Cox比例模型迴歸方程式估計。
所有受試者中，相較於總分最低者（0分），總分最高者（5分），與胰臟癌風險下降58%有關（相對風險為0.42；95%信賴區間為0.26-0.66；趨勢P值為<0.001）；在這個試驗族群中，分數低於5分者，與27%胰臟癌病例有關。
研究作者寫道，這項大型研究的發現顯示，相較於總分低，總分較高結合這五種生活型態指標顯著降低發生胰臟癌的風險；合併健康型態因子包括沒有吸菸、對美國飲酒建議的依從性、健康的飲食品質，以對地中海飲食模式的遵從性定義，排除飲酒、正常的體重、以及規律的運動，可能對於美國老年病患預防胰臟癌有直接的意義。
這項研究的限制包括源自於這五個因子二變項可能流失的統計力量；每個因子僅有一次試驗前的評量；且缺乏合併所有可能是胰臟癌危險因子的生活型態、職業暴露或是醫療史分數。
研究團隊的結論是，雖然進一步搜尋致癌原因或是機轉，可能讓我們找到全新的預防策略，但在癌症風險評估中，檢驗已知合併可修飾的因子，是一個轉化流行病學分析數據為初級癌症預防的適當方法，特別是預防早期診斷和治療仍然是項挑戰的胰臟癌。
國家衛生研究院、國家癌症機構癌症流行病學與基因學贊助這項研究。研究作者們表示沒有相關資金上的往來。
Index Combines 5 Modifiable Lifestyle Factors Linked With Risk for Pancreatic Cancer
By Laurie Barclay, MD
Medscape Medical News
May 5, 2009 — Having a high score vs a low score on an index combining 5 modifiable lifestyle factors predicted a substantially lower risk for the development of pancreatic cancer, according to the results of a large, prospective study reported in the April 27 issue of the Archives of Internal Medicine.
"Smoking, alcohol use, diet, body mass index ([BMI] calculated as weight in kilograms divided by height in meters squared), and physical activity have been studied independently in relation to pancreatic cancer," write Li Jiao, MD, from National Cancer Institute, National Institutes of Health in Bethesda, Maryland, and colleagues. "We generated a healthy lifestyle score to investigate their joint effect on risk of pancreatic cancer."
The study cohort consisted of 450,416 participants enrolled in the National Institutes of Health-AARP Diet and Health Study, who were aged 50 to 71 years, who completed the baseline food frequency questionnaire from 1995 to 1996 regarding diet and lifestyle information, and who were followed up through December 31, 2003. During follow-up, 1057 eligible incident pancreatic cancer cases were identified.
For each participant, 5 modifiable lifestyle factors were scored as unhealthy (0 points) or healthy (1 point), based on current epidemiologic evidence. One point was awarded for each of the following: nonsmoking, limited alcohol use, adherence to the Mediterranean dietary pattern, body mass index (? 18 and < 25 kg/m2), and regular physical activity. The combined score (0 - 5?points) was determined by adding the scores for each of the 5 factors. Relative risk for pancreatic cancer was estimated with Cox proportional hazards regression models.
The highest combined score (5 points) vs the lowest score (0 points) was associated with a 58% reduction in the risk for the development of pancreatic cancer in all participants (relative risk, 0.42; 95% confidence interval, 0.26 - 0.66; P for trend < .001). In this study cohort, scores of less than 5 points were associated with 27% of pancreatic cancer cases.
"Findings from this large study suggest that having a high score, as opposed to a low score, on an index combining 5 modifiable lifestyle factors substantially reduces the risk of developing pancreatic cancer," the study authors write. "The combined healthy lifestyle factors including nonsmoking, adherence to US alcohol use recommendation, healthy dietary quality as defined by adherence to the Mediterranean diet pattern excluding alcohol consumption, normal weight, and regular physical activity may have direct implications for pancreatic cancer prevention in older individuals in the United States."
Limitations of this study include possible loss of study power resulting from dichotomization of each of the 5 factors; only 1 baseline measure for each factor; and lack of inclusion in the combined score of all possible lifestyles, occupational exposure, or medical history that could be risk factors for pancreatic cancer.
"Although further searching for cancer-causing factors or mechanisms may contribute to innovative preventive strategies, the examination of combined known modifiable factors in cancer risk assessment is an appropriate way to translate analytic epidemiologic findings to primary cancer prevention, especially for the prevention of pancreatic cancer for which both early diagnosis and effective treatment remain challenging," the study authors conclude.
The National Institutes of Health, National Cancer Institute, Division of Cancer Epidemiology and Genetics, supported this study. The study authors have disclosed no relevant financial relationships.
Arch Intern Med. 2009;169:764-770. |
|
