Obtaining informed consent for genetic studies: The multiethnic study of atherosclerosis.

Studies of DNA may yield important information about atherosclerosis. To determine how often study participants' consent to examine DNA is denied and the factors associated with that denial, information was collected on participants in the US Multiethnic Study of Atherosclerosis (MESA) during 2000-2004. Permission was sought for preparation of DNA, transformation of cells into cell lines, evaluation of genes related to heart and other health conditions, and access to DNA by private companies. Of the 5,494 participants at entry, 897 (16.3%) refused consent for some items and 247 (4.5%) completely denied consent. At a second examination 18 months later, 819 (15.0%) partially refused and 229 (4.2%) completely denied consent. Age among men (odds ratio per 10 years = 0.68, 95% confidence interval: 0.54, 0.85; p = 0.004), ethnicity (odds ratio for African American = 2.34, 95% confidence interval: 1.66, 3.32; p < 0.001), and field center (p < 0.001) were associated with complete denial. For those giving partial consent, the most common item refused was access to DNA by private companies (baseline: 99%; second examination: 90%); younger age, male gender, and African-American ethnicity were associated with refusal. The authors concluded that a small percentage of participants in epidemiologic studies refuse consent for DNA studies, and the majority are concerned about sharing their DNA data with industry.