OBJECTIVES: One of the consequences of an aging population is the emerging importance of genetically-linked disorders which develop in later life. Many of these disorders affect the central nervous system and result in progressive degeneration of higher functions and dementia. This research expands on observations described in a previous presentation (PMC53, ISPOR 2008) concerning the influence of genetic discoveries on the number of probable RCTs in Alzheimer’s disease (AD) and Huntington’s disease (HD) to explore other measures of interest.METHODS: A citation search was conducted in Medline for the years 1951 to 2005 (5-yearly time periods). Search filters for RCTs, economic studies (ES), and observational studies (OS)  (www.sign.ac.uk/methodology/filters.html) combined with search strings incorporating the MeSH terms for each disorder were run to provide an estimate of interest in these disorders. The x-fold increases (2001-2005/1976-1980) were calculated and the data were analysed using logistic regression.RESULTS: There were 12,820,265 publications during 1951 to 2005, with 57,466 relating to AD and 8304 relating to HD. Over the past 30 years the interest in AD has been increasing, with 62-fold increases in the number of papers published within this disease area. In contrast, during the same time period publications in HD showed only a 4-fold increase. This disparity is particularly notable for probable RCTs, where there were 405-fold increases in AD but only 5-fold increases in HD. Interestingly the interest in AD predates the identification of several genetic linkages that occurred in the late 1990’s. Conversely, the discovery of huntingtin in 1993 appears to have had little effect on interest in HD.CONCLUSIONS: Improvements and advances in sanitation, nutrition and immunisation against infectious diseases have combined with other factors to reduce mortality and prolong life expectancies. One of the most important consequences of increased life expectancy is the emergence of genetically linked disorders which develop in later life. Discovery of genetic linkage does not appear to be a strong predictor of research activity, in the case of AD and HD.