Barrett Jennifer H
Section of Genetic Epidemiology and Biostatistics, Leeds Institute of Molecular Medicine, St James's University Hospital, Leeds, UK.
Methods Mol Med. 2008;141:55-69. doi: 10.1007/978-1-60327-148-6_4.
Complex diseases and traits are influenced by a combination of genetic and environmental risk factors, some of which may be known, and many of which are unknown. It is possible to estimate the relative importance of the influence of genes and environment on a trait by studying correlations in the trait in related individuals. Known risk factors can be measured and included in the statistical models to understand disease etiology better. The joint effect of specific genes and environmental exposures can be estimated by measuring these in individuals, not necessarily related, with and without the disease of interest or with a range of trait values. These methods are illustrated by considering two example analyses in detail. The first is an analysis of a study of adolescent twins, quantifying the effect of genes and environment, including measured sun exposure, on the density of nevi. The second is an analysis of a case-control study, examining the joint effect of the GSTT1 gene and vegetable intake on risk of colorectal cancer.
复杂疾病和性状受到遗传和环境风险因素的共同影响，其中一些因素可能已知，而许多因素尚不清楚。通过研究相关个体中该性状的相关性，可以估计基因和环境对某一性状影响的相对重要性。可以测量已知的风险因素并将其纳入统计模型，以便更好地理解疾病病因。通过在患有或未患有感兴趣疾病或具有一系列性状值的个体（不一定相关）中测量特定基因和环境暴露，可以估计它们的联合效应。通过详细考虑两个示例分析来说明这些方法。第一个是对青少年双胞胎的一项研究分析，量化基因和环境（包括测量的阳光暴露）对痣密度的影响。第二个是对一项病例对照研究的分析，研究GSTT1基因和蔬菜摄入量对结直肠癌风险的联合效应。
