Scientific research supported by the National Institutes of Health (NIH) has been of great benefit to the health of the population in the United States. Research to improve diagnosis, treatment, and prevention has led to improvements in health care for most Americans, and significant declines in morbidity and mortality from numerous diseases. As a result, the population can expect not only to live longer but also to be more productive and to enjoy a higher quality of life. However, these gains have not affected all segments of the population equally. Minority populations in the United States continue to experience substantial disparities in the burden of disease and death when compared to the majority population.