Department of Community Health and Epidemiology, Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Canada.
J Agromedicine. 2012;17(3):316-25. doi: 10.1080/1059924X.2012.686381.
A common source of bias in epidemiological studies is self-selection or volunteer bias. The self-selection into cohorts for further investigation or for participation in a substudy may be an important source of selection bias. The objectives of this paper were to identify differences in selected demographic characteristics, individual and contextual factors, and variables related to respiratory health between study participants who were willing to participate in subsequent clinical and allergy testing and those who were not willing to participate. One hundred and fourteen households (207 individuals) from a small town and 54 households (99 individuals) from a nearby rural municipality participated in this study. One key informant from each household provided information about each adult in that household. The question being studied was: "We wish to find out more about respiratory health of rural people. We would like to invite you to perform breathing and allergy tests. Would you be willing to be contacted for breathing and allergy tests in a nearby location?" One hundred and four participants said "Yes" they would participate in the clinical studies, 144 said "No" they would not participate in the clinical studies, and 52 said "Would like more information" about the clinical studies. More than one half (53.8%) of male participants and 46.2% of female participants indicated that they would like to participate in breathing and allergy tests. A higher proportion of study participants (26.1% males, 30.8% females) in the lowest income category requested more information compared to those answering either "Yes" (15.7% for males, 20.5% for females) or "No" (18.5% males, 23.3% females) to the question being studied. Study participants who were willing to participate in further breathing and allergy tests had a higher proportion of self-reported chronic phlegm and ever had allergic reaction to things eaten than those who either said "No" or "Would like more information." Among male study participants who said "Yes" to further participation, a higher proportion was exposed to one of the occupational exposures of interest compared to those who said either "No" or "Would like more information." This pattern was not observed for females.
在流行病学研究中，一个常见的偏倚来源是自我选择或志愿者偏倚。进一步调查或参与亚研究的队列中的自我选择可能是选择偏倚的一个重要来源。本文的目的是确定愿意参加后续临床和过敏测试的研究参与者与不愿意参加的研究参与者之间在选定的人口统计学特征、个体和背景因素以及与呼吸健康相关的变量方面的差异。来自一个小镇的 114 户家庭（207 人）和附近农村自治市的 54 户家庭（99 人）参加了这项研究。每个家庭的一名关键知情者提供了该家庭每个成年人的信息。正在研究的问题是：“我们希望更多地了解农村人民的呼吸健康。我们想邀请您进行呼吸和过敏测试。您是否愿意在附近的地方接受呼吸和过敏测试？” 104 名参与者表示愿意参加临床研究，144 名参与者表示不愿意参加临床研究，52 名参与者表示希望了解更多关于临床研究的信息。超过一半（53.8%）的男性参与者和 46.2%的女性参与者表示愿意参加呼吸和过敏测试。收入最低类别的研究参与者（26.1%的男性，30.8%的女性）要求更多信息的比例高于回答“是”（15.7%的男性，20.5%的女性）或“否”（18.5%的男性，23.3%的女性）的比例。愿意进一步参加呼吸和过敏测试的研究参与者比回答“否”或“希望了解更多信息”的参与者报告有更高比例的慢性咳痰和曾经对吃过的东西有过敏反应。在表示愿意进一步参与的男性研究参与者中，与回答“否”或“希望了解更多信息”的参与者相比，有更高比例的人接触到感兴趣的职业暴露之一。对于女性研究参与者来说，这种模式并不明显。
