Ethnicity and the ethics of data linkage

Health services are required to demonstrate that they are meeting the needs of ethnic minority populations. This is difficult, because routine data on health rarely include reliable data on ethnicity. But data on ethnicity are included in census returns, and if health and census data for the same individuals can be linked, the problem might be solved. These conditions apply in Scotland, where an innovative study, linking the health and ethnic data of 4.6 million people, has uncovered important information about the incidence of, and survival after, acute myocardial infarction among South Asians [1]. Linkage was achieved by techniques, developed to protect the anonymity of the individuals involved, which ensured compliance with data protection legislation and received appropriate regulatory approval. This pioneering study paves the way for further work which could have considerable importance for health service planning and, its authors suggest, potentially has international applicability. The benefits of linking health and ethnic data could be great. But are there also harms? Two ethical objections to data linkage need to be answered.The first objection concerns informed consent. Individuals who stated their ethnicity in census returns were not told that this might subsequently be linked with their health data. Their consent to providing this personal data thus was not fully informed, and so it cannot be relied upon as valid consent. The only ethically correct course is to return to each of these individuals and seek explicit informed consent for this specific use of their personal data.Given the impracticability of this requirement, it may be tempting to dismiss this objection as ethically disproportionate: the potential benefits of data linkage surely vastly outweigh the merits of such moral scruples. But not all official uses of personal information about citizens are potentially innocent, and overruling the principle of informed consent is morally hazardous. Whe