{"id":3342,"date":"2015-03-23T10:24:53","date_gmt":"2015-03-23T14:24:53","guid":{"rendered":"http:\/\/blogs.cdc.gov\/genomics\/?p=3342"},"modified":"2024-04-08T16:39:46","modified_gmt":"2024-04-08T20:39:46","slug":"when-a-country","status":"publish","type":"post","link":"https:\/\/blogs.cdc.gov\/genomics\/2015\/03\/23\/when-a-country\/","title":{"rendered":"When a Country Cannot be a Cohort: Challenges of Implementing a Large Precision Medicine Cohort Study in the United States"},"content":{"rendered":"

\"a<\/a>The recently proposed US precision medicine<\/a> initiative promises a new era of healthcare with targeted disease treatment and prevention. It prominently features a longitudinal study of a national cohort of a million or more people to customize interventions based on a person’s genetics and other factors. The long term goal of this study is to \u201cgenerate the knowledge base necessary to move precision medicine into virtually all areas of health and disease\u201d. \u00a0Other countries have already launched large national cohorts and biobanks to examine genetic and environmental factors in relation to human diseases. Conducting a cohort study in the US is particularly challenging from a number of vantage points. To explore these challenges, let us briefly consider what has been done in Denmark where \u201cthe entire country is a cohort\u201d.<\/a><\/p>\n

Denmark has gathered more data on its citizens than any other country. The Danish Civil Registration System (CRS)<\/a> contains individual-level information on all residents of Denmark (and Greenland as of 1972). By January 2014, the CRS had registered 9.5 million individuals and more than 400 million person-years of follow-up. A unique ten-digit Civil Personal Register number assigned to all persons in the CRS allows individual-level record linkage of all Danish registers. Daily updated information on migration and vital status allows for nationwide cohort studies with virtually complete long-term follow-up on emigration and death. The CRS facilitates sampling of general population comparison cohorts, controls in case\u2013control studies, family studies and targeted population surveys. The data in the CRS are virtually complete, have high accuracy, and can be retrieved for research purposes while protecting the anonymity of Danish residents. Although other Scandinavian countries have their own databases, Denmark has the reputation for possessing the most complete collection of statistics<\/a> and databases touching on almost every aspect of life. The Danish government has compiled nearly 200 databases, some begun in the 1930s, on everything from medical records to socioeconomic data on jobs and salaries. These databases \u201callow for instant, large cohort studies that are impossible in most countries.\u201d Examples of genetic studies using this unique resource include studies of genes and lifestyle in aging using the Danish Twin Register<\/a> which includes 110,000 pairs of twins. Another example is a recent series of genomewide association studies that have identified genetic factors associated with febrile seizures in children after receiving the measles, mumps, and rubella (MMR) vaccine.<\/a><\/p>\n

In the United States, a recent NIH workshop<\/a> explored issues and challenges for creating a national cohort of at least one million Americans to advance our understanding of heath and disease. One outcome of the NIH workshop was the identification of barriers in establishing a large cohort:<\/p>\n