Characteristics of 6 case-control studies included in the meta-analysis.

MI, myocardial infarction; CHD, coronary heart disease; WHO, World Health Organization; N.S., not stated.*Indicates significant difference in the occurrence of CHD risk factor between case and control populations.†Patients were recruited following angiography demonstrating greater than 30% reduction in the diameter of one or more coronary arteries.‡Author did not provide relevant data, but stated that cases and controls were matched for age and sex.

MI（myocardial infarction，心肌梗死）；CHD（coronary heart disease，冠心病）；WHO（World Health Organization，世界卫生组织）；N.S.（not stated，未注明）。
* 表示病例组与对照组在冠心病危险因素的发生情况上存在显著性差异。
† 患者招募标准为经血管造影证实单支或多支冠状动脉直径狭窄程度超过30%。
‡ 作者未提供相关数据，但提及病例组与对照组在年龄及性别上进行了匹配。