Thrusfield M V
Veterinary Clinical Sciences, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
J Comp Pathol. 2010 Jan;142 Suppl 1:S22-32. doi: 10.1016/j.jcpa.2009.10.014. Epub 2009 Dec 1.
Major goals of epidemiology are estimation of disease morbidity and mortality and identification and quantification of the impact of risk factors. Age is a recognized risk factor, contributing to the occurrence of multifactorial diseases. Cohort, case-control and cross-sectional observational studies identify age and other putative risk factors and quantify their impact on disease occurrence by estimating relative risks and odds ratios. Ageing per se is not a key concern of epidemiologists, and detailed biological explanations of causal mechanisms may not be offered by the epidemiologist. Nevertheless, the relationships identified in epidemiological studies can offer practical solutions to disease prevention. Age also can confound relationships between disease and other putative risk factors and must be controlled during epidemiological study design and analysis, in order to avoid spurious causal inferences. Additionally, age can modify the effect of other risk factors, necessitating identification of such interactions and the differentiation of effect modifiers from confounders. Comparative epidemiology frequently compares human and animal populations. Meaningful comparisons can only be made by undertaking life span adjustment and age adjustment on animal study data, to address differences between the two populations stemming from different 'biological ages' and age structures, respectively.
流行病学的主要目标是估计疾病的发病率和死亡率，以及识别和量化风险因素的影响。年龄是一个公认的风险因素，会促使多因素疾病的发生。队列研究、病例对照研究和横断面观察性研究可识别年龄及其他假定的风险因素，并通过估计相对风险和比值比来量化它们对疾病发生的影响。衰老本身并非流行病学家主要关注的问题，而且流行病学家可能不会提供因果机制的详细生物学解释。然而，流行病学研究中确定的关系可为疾病预防提供切实可行的解决方案。年龄也可能混淆疾病与其他假定风险因素之间的关系，因此在流行病学研究设计和分析过程中必须对其加以控制，以避免得出虚假的因果推断。此外，年龄可能会改变其他风险因素的作用，因此有必要识别此类相互作用，并区分效应修饰因素和混杂因素。比较流行病学经常对人类和动物群体进行比较。只有对动物研究数据进行寿命调整和年龄调整，以分别解决由于不同的“生物学年龄”和年龄结构导致的两个群体之间的差异，才能进行有意义的比较。
