Navigating a four-university, three-country collaboration to estimate mortality in Iraq after the 2003 invasion and occupation

Abstract

Abstract Background We organised a four-university collaboration to estimate mortality attributable to the 2003 invasion and occupation of Iraq, including both direct and indirect deaths. The 12 researchers involved were all volunteers, crossing boundaries of three nations to participate in the study. Methods We did a survey of 2000 randomly-selected households throughout Iraq, using a two-stage cluster sampling method to ensure households were nationally representative. We asked each head of household about births and deaths since 2001, and all household adults about mortality among their siblings. We estimated the number of deaths caused directly and indirectly by conflict, for the general population (household survey) and for adults aged 15–60 years (sibling survey). Our sample selection process involved an innovative approach, using Google Earth maps loaded with population data. Institutional review board approval was a challenging barrier to a rapid study start-up, because such boards have little experience with the conduct of ethical research in settings of war. Scientific methods for estimations of mortality in settings of high mobility and violence are not yet refined. Findings From March, 2003, to June, 2011, the crude death rate in Iraq was 4·55 per 1000 (95% CI 3·74–5·27), more than 0·5 times higher than the death rate during the 2-year period preceding the war, resulting in roughly 405 000 (48 000–751 000) excess deaths attributable to the conflict. Of adults, the risk of death rose 0·7 times higher for women and 2·9 times higher for men between the prewar period (2001 to February, 2003) and the peak of the war (2005–06). More than 60% of excess deaths were directly attributable to violence, with the rest associated with the collapse of infrastructure and other indirect, war-related causes. We estimate at least 55 000 deaths that would have been reported by households had they remained behind in Iraq, but instead had migrated away. Interpretation Analysis of results was made difficult by the absence of established methods for estimating mortality among those who migrated away. Most mortality increases in Iraq can be attributed to direct violence, but about a third are attributable to indirect causes (such as from failures of health, sanitation, transportation, communication, and other systems). Roughly half a million deaths in Iraq could be attributable to the war. Funding None.