Prentice R L, Sheppard L
Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle WA 98104.
Cancer Causes Control. 1990 Jul;1(1):81-97; discussion 99-109. doi: 10.1007/BF00053187.
International variations and national time trends in disease rates suggest major associations between dietary fat and several important cancers. In contrast, case-control and cohort studies of dietary fat in relation to the same cancers generally report weak associations, or have failed to detect any association with fat intake. This study was undertaken in an attempt to understand the apparent discrepancy between these observations. The results provide an insight into the magnitude of cancer risk reduction that may follow from a practical reduction in dietary fat. Regression analyses of international variations in cancer incidence rates were used to estimate relative risks (RR) as a function of fat intakes for both males and females. These analyses focused on cancers of the breast, colon, rectum, ovary, and endometrium in females, and colon, rectum, and prostate cancers in males. Ages 55-69 and 30-44 were considered in order to compare RR estimates between an older and younger age group, and between post- and pre-menopausal women. Corresponding RR estimates were also calculated, based on the regression of changes in disease rates from the mid-1960s to 1980 on changes in dietary fat, using data from several countries. A strong degree of consistency with the RR estimates from international comparisons was observed. The international regression analyses were also used to project changes in cancer rates among Japanese migrants to the United States. A high level of consistency with the observed disease-rate changes was noted. Similarly, the international data analyses were used to project RRs for the fat intake categories used in specific case-control and cohort studies, while acknowledging measurement error in individual dietary assessment. Although certain exceptions are noted, considerable consistency was found between the aggregate and analytic data results, leaving open the strong possibility that a practical reduction in dietary fat could result in a major reduction in the incidence of several prominent cancers in the United States and in other nations having high fat consumption.
疾病发病率的国际差异和各国的时间趋势表明，膳食脂肪与几种重要癌症之间存在主要关联。相比之下，关于膳食脂肪与这些相同癌症的病例对照研究和队列研究通常报告的关联较弱，或者未能发现与脂肪摄入量有任何关联。进行这项研究是为了试图理解这些观察结果之间明显的差异。研究结果深入了解了通过实际减少膳食脂肪可能实现的癌症风险降低幅度。利用癌症发病率的国际差异进行回归分析，以估计男性和女性脂肪摄入量函数的相对风险（RR）。这些分析聚焦于女性的乳腺癌、结肠癌、直肠癌、卵巢癌和子宫内膜癌，以及男性的结肠癌、直肠癌和前列腺癌。考虑了55 - 69岁和30 - 44岁这两个年龄段，以便比较老年和年轻年龄组之间以及绝经后和绝经前女性之间的RR估计值。还根据20世纪60年代中期至80年代疾病发病率变化与膳食脂肪变化的回归分析，利用几个国家的数据计算了相应的RR估计值。观察到与国际比较得出的RR估计值有高度一致性。国际回归分析还用于预测日本移民到美国后的癌症发病率变化。注意到与观察到的疾病发病率变化有高度一致性。同样，国际数据分析用于预测特定病例对照研究和队列研究中使用的脂肪摄入类别的RR，同时承认个体膳食评估中的测量误差。尽管注意到某些例外情况，但汇总数据和分析数据结果之间发现了相当大的一致性，这使得膳食脂肪的实际减少很有可能导致美国以及其他高脂肪消费国家几种主要癌症的发病率大幅降低。
