Studying injuries with case-control methods in the emergency department

Misconceptions regarding case-control studies of bicycle helmets and head injury

A number of published case-control studies have reported that bicycle helmets are associated with a reduced risk of head injury and brain injury among bicyclists who crashed. A paper in this journal offered several criticisms of these studies and of a systematic review of these studies. Many of those criticisms stem from misconceptions about the studies that have been done and about case-control studies in general. In this manuscript we review case-control study design, particularly as it applies to bicycle helmet studies, and review some aspects of the analysis of case-control data.

An unmatched case-control study of nearly lethal suicide attempts in Houston, Texas: research methods and measurements

This article details the research methods and measurements used in conducting a population-based, case-control study of nearly lethal suicide attempts among persons aged 13-34 years, residing in Houston, Texas. From November 1992 to July 1995, we interviewed 153 case subjects presenting at one of three participating hospital emergency departments and used random digit dialing to identify 513 control subjects residing in the same catchment area in which cases were enlisted. Unlike most research in this area, this study was designed to extend our understanding of suicidal behavior and prevention activities beyond identification and treatment of depression and other mental illnesses. We discuss the overall strengths and weaknesses of our study design and conclude that this methodology is well suited for studying rare outcomes such as nearly lethal suicide.