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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　May 11, 2010 — 根據一項5月10日線上發表於循環（Circulation）期刊的研究，罹患第二型糖尿病女性攝取全穀和麸糠與死亡率較低有關。
　　
　　資深作者麻州波士頓哈佛大學公衛學院的Lu Qi醫師在一篇新聞稿中表示，就我所知，這是第一項針對糖尿病患者使用全穀以及其成分對死亡風險影響的研究。相較於一般大眾，糖尿病患者發生心血管疾病與早死風險高出2~3倍。
　　
　　護士健康研究第一部分，美國7822位罹患第二型糖尿病女性完成常規行政問卷，評估飲食攝取與潛在的影響因子。在長達26年的後續追蹤中，總共發生852件所有原因死亡事件與295件心血管死亡事件。
　　
　　相較於攝取全穀類、穀類纖維、麸糠與胚芽最低的五分位數，攝取最多的患者，在校正年齡後，所有原因死亡率低了16%~31%。然而，在校正生活型態與飲食危險因子後，只攝取麸糠仍然顯著相關（趨勢P值為0.01）。在攝取麸糠的五分位數之間，多變項相對危險為1.0（參考值）、0.94（95%信賴區間[CI]為0.75-1.18）、0.80（95% CI為0.64-1.01）、0.82（95% CI為0.65-1.04）與0.72（95% CI為0.56-0.92）。
　　
　　攝取麸糠也反向地與心血管死亡率相關，攝取麸糠不同五分位數之間的相對風險分別為1.0（參考值）、0.95（95% CI為0.95-1.38）、0.80（95% CI為0.55-1.16）、0.76（95% CI為0.51-1.14）與0.65（95% CI為0.43-0.99；趨勢P值為0.04）。僅加入麸糠的發現也是差不多的。
　　
　　Qi醫師表示，這些發現代表，攝取全穀，特別是麸糠，與降低糖尿病患者的死亡及心血管風險有關。
　　
　　這項研究的限制包括可能未經控制、未量測到的影響因子，飲食攝取評估的測量錯誤、沒有足夠統計力量偵測些微關係，以及缺乏應用到男性與非白人種族的全面性。
　　
　　Qi醫師的結論是，糖尿病被認為是一種慢性發炎狀態，特徵是發炎與內皮細胞功能不全的化學指標上升。那些指標已經被發現與糖尿病及非糖尿病患者CVD（心臟血管疾病）風險增加有關。在我們過去的研究中，我們已經報告攝取全穀類及其次產物，例如穀類纖維可能降低糖尿病患者的這些指標。
　　
　　國家衛生研究院、美國心臟醫學會科學家發展獎學金、以及波士頓肥胖營養研究中心贊助這項研究。試驗作者們表示沒有相關資金上的往來。


Whole Grain, Bran Intake Linked to Lower Mortality in Diabetic Women

By Laurie Barclay, MD
Medscape Medical News

May 11, 2010 — Whole grain and bran intake are linked to lower mortality rates in women with type 2 diabetes, according to the results of a study reported online May 10 in Circulation.

"To my knowledge, this is the first study of whole grain and its components and risk of death in diabetic patients," said senior author Lu Qi, MD, PhD, from Harvard Medical School and Harvard School of Public Health in Boston, Massachusetts, in a news release. "Patients with diabetes face 2 to 3 times the risk of cardiovascular disease and premature death compared to the general population."

As part of the Nurses' Health Study, 7822 US women with type 2 diabetes mellitus completed regularly administered questionnaires evaluating dietary intakes and potential confounders. During follow-up lasting up to 26 years, there were 852 all-cause deaths and 295 cardiovascular deaths.

Compared with the lowest fifths of intakes of whole grain, cereal fiber, bran, and germ, the highest fifths were associated with 16% to 31% lower all-cause mortality rate, after adjustment for age. However, only the association for bran intake remained significant after further adjustment for lifestyle and dietary risk factors (P for trend = .01). Across the fifths of bran intake, the multivariate relative risks were 1.0 (reference), 0.94 (95% confidence interval [CI], 0.75 - 1.18), 0.80 (95% CI, 0.64 - 1.01), 0.82 (95% CI, 0.65 - 1.04), and 0.72 (95% CI, 0.56 - 0.92).

Bran intake was also inversely associated with cardiovascular mortality, with relative risks across the fifths of bran intake being 1.0 (reference), 0.95 (95% CI, 0.66 - 1.38), 0.80 (95% CI, 0.55 - 1.16), 0.76 (95% CI, 0.51 - 1.14), and 0.65 (95% CI, 0.43 - 0.99; P for trend = .04). For added bran alone, findings were similar.

"These findings suggest a potential benefit of whole grain, and particularly bran, in reducing death and cardiovascular risk in diabetic patients," Dr. Qi said.

Limitations of this study include possible uncontrolled and unmeasured confounders, measurement error of dietary intake assessment, insufficient power to detect modest associations, and lack of generalizability to men and nonwhite ethnic groups.

"Diabetes is thought to be a chronic state of inflammation characterized by moderately increased levels of chemical markers for inflammation and endothelial dysfunction," Dr. Qi concluded. "Those markers have been found to be related to increased risk of CVD [cardiovascular disease] in both diabetic and non-diabetic populations. In our previous studies, we have reported that intakes of whole grains and subcomponents such as cereal fiber may lower these markers in diabetic patients."

The National Institutes of Health, the American Heart Association Scientist Development Award, and the Boston Obesity Nutrition Research Center supported this study. The study authors have disclosed no relevant financial relationships.

Circulation. Published online May 10, 2010.