Hebert J R, Hurley T G, Olendzki B C, Teas J, Ma Y, Hampl J S
Division of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester 01655, USA.
J Natl Cancer Inst. 1998 Nov 4;90(21):1637-47. doi: 10.1093/jnci/90.21.1637.
Large international variations in rates of prostate cancer incidence and mortality suggest that environmental factors have a strong influence on the development of this disease. The purpose of this study was to identify predictive variables for prostate cancer mortality in data from 59 countries.
Data on prostate cancer mortality, food consumption, tobacco use, socioeconomic factors, reproductive factors, and health indicators were obtained from United Nations sources. Linear regression models were fit to these data. The influence of each variable fit in the regression models was assessed by multiplying the regression coefficient b by the 75th (X75) and 25th (X25) percentile values of the variable. The difference, bX75 - bX25, is the estimated effect of the variable across its interquartile range on mortality rates measured as deaths per 100000 males aged 45-74 years. Reported P values are two-sided.
Prostate cancer mortality was inversely associated with estimated consumption of cereals (bX75 - bX25 = -7.31 deaths; P = .001), nuts and oilseeds (bX75 - bX25 = -1.72 deaths; P = .003), and fish (bX75 - bX25 = -1.47 deaths; P = .001). In the 42 countries for which we had appropriate data, soy products were found to be significantly protective (P = .0001), with an effect size per kilocalorie at least four times as large as that of any other dietary factor. Besides variables related to diet, we observed an association between prostate cancer mortality rates and a composite of other health-related, sanitation, and economic variables (P = .003).
The specific food-related results from this study are consistent with previous information and support the current dietary guidelines and hypothesis that grains, cereals, and nuts are protective against prostate cancer. The findings also provide a rationale for future study of soy products in prostate cancer prevention trials.
前列腺癌发病率和死亡率在国际上存在很大差异，这表明环境因素对该疾病的发展有很大影响。本研究的目的是在来自59个国家的数据中确定前列腺癌死亡率的预测变量。
从联合国来源获取前列腺癌死亡率、食物消费、烟草使用、社会经济因素、生殖因素和健康指标的数据。对这些数据拟合线性回归模型。通过将回归系数b乘以变量的第75百分位数（X75）和第25百分位数（X25）来评估回归模型中每个变量拟合的影响。差值bX75 - bX25是该变量在其四分位间距内对以每100000名45 - 74岁男性死亡数衡量的死亡率的估计效应。报告的P值为双侧。
前列腺癌死亡率与谷物估计消费量（bX75 - bX25 = -7.31例死亡；P = 0.001）、坚果和油籽（bX75 - bX25 = -1.72例死亡；P = 0.003）以及鱼类（bX75 - bX25 = -1.47例死亡；P = 0.001）呈负相关。在我们有合适数据的42个国家中发现，大豆制品具有显著的保护作用（P = 0.0001），每千卡的效应大小至少是任何其他饮食因素的四倍。除了与饮食相关的变量外，我们还观察到前列腺癌死亡率与其他健康相关、卫生和经济变量的综合指标之间存在关联（P = 0.003）。
本研究中与食物相关的具体结果与先前的信息一致，并支持当前的饮食指南以及谷物、谷类和坚果对前列腺癌有预防作用的假设。这些发现也为未来在前列腺癌预防试验中研究大豆制品提供了理论依据。
