Imamura Fumiaki, Lichtenstein Alice H, Dallal Gerard E, Meigs James B, Jacques Paul F
Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging and the Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, USA.
Am J Epidemiol. 2009 Jul 1;170(1):37-45. doi: 10.1093/aje/kwp096. Epub 2009 May 8.
The ability to interpret epidemiologic observations is limited because of potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome the limitation. To examine confounding by dietary pattern as well as standard risk factors and selected nutrients, the authors modeled the longitudinal association between alcohol consumption and 7-year risk of type 2 diabetes mellitus in 2,879 healthy adults enrolled in the Framingham Offspring Study (1991-2001) by Cox proportional hazard models. After adjustment for standard risk factors, consumers of > or =9.0 drinks/week had a significantly lower risk of type 2 diabetes mellitus compared with abstainers (hazard ratio = 0.47, 95% confidence interval (CI): 0.27, 0.81). Adjustment for selected nutrients had little effect on the hazard ratio, whereas adjustment for dietary pattern variables by factor analysis significantly shifted the hazard ratio away from null (hazard ratio = 0.33, 95% CI: 0.17, 0.64) by 40.0% (95% CI: 16.8, 57.0; P = 0.002). Dietary pattern variables by partial least squares showed similar results. Therefore, the observed inverse association, consistent with past studies, was confounded by dietary patterns, and this confounding was not captured by individual nutrient adjustment. The data suggest that alcohol intake, not dietary patterns associated with alcohol intake, is responsible for the observed inverse association with type 2 diabetes mellitus risk.
由于相关饮食成分可能存在残余混杂因素，对流行病学观察结果的解读能力受到限制。通过因子分析或偏最小二乘法进行饮食模式分析可能会克服这一限制。为了研究饮食模式以及标准风险因素和选定营养素的混杂作用，作者通过Cox比例风险模型对参加弗雷明汉后代研究（1991 - 2001年）的2879名健康成年人中酒精摄入量与2型糖尿病7年发病风险之间的纵向关联进行了建模。在对标准风险因素进行调整后，每周饮用≥9.0杯酒的消费者与戒酒者相比，患2型糖尿病的风险显著降低（风险比 = 0.47，95%置信区间（CI）：0.27，0.81）。对选定营养素进行调整对风险比影响不大，而通过因子分析对饮食模式变量进行调整则使风险比显著偏离无效值（风险比 = 0.33，95% CI：0.17，0.64），偏移了40.0%（95% CI：16.8，57.0；P = 0.002）。通过偏最小二乘法得出的饮食模式变量显示了类似的结果。因此，与过去的研究一致，观察到的反向关联受到饮食模式的混杂影响，而这种混杂作用未被个体营养素调整所捕捉。数据表明，是酒精摄入量而非与酒精摄入相关的饮食模式导致了观察到的与2型糖尿病风险的反向关联。
