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J.H. Baird, N. Zabriskie, P.S. Bernstein, R. Gomez, R. MacArthur, Z. Yang, E. Pearson, K. Zhang; Genetic Epidemiology of Age–Related Macular Degeneration Using the Utah Population Database . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2707.
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© ARVO (1962-2015); The Authors (2016-present)
Age–related macular degeneration (AMD) is the leading cause of blindness in the US and the developed world. It is difficult to assess to what extent familial history increases the risk of developing AMD due to the multi–factorial nature of the disease. The Utah Population Database (UPDB) was created by the University of Utah (U of U) and contains over 9 million records, including genealogies, birth and death certificates, and drivers’ license data. The two major data sets from which family members can be identified are the 2 million Utah birth certificates, and 1.6 million genealogy records, spanning as many as 11 generations.
Uof U’s 1.5 million unique hospital and clinic records were searched, and patients with AMD were identified using ICD9 codes (362.5 for GA; 362.51 for dry AMD; 362.52 for CNV and wet AMD.) Case–Control analysis was performed with specialized UPDB software that was modified to constrain the control and pedigree populations to over one million U of U–UPDB linked records from 1995–2005. Controls were matched to cases by gender and birth year +/– 2.5 years. Only one control was picked per case, and the controls were not reused. Population of attributable risk to familial factors (PAR) and relative risk (RR) were both computed using conditional logistic regressions (CLR).
From 1.5 million medical records, 4764 AMD patients were identified. 2272 of these 4764 AMD patients were used in the analysis; the others were eliminated because they had no parents and no children identified in the UPDB. Using data from CLR computations, the adjusted population attributable risk (PAR) is 0.34, so 34% of the risk for AMD is attributable to a familial component. Increased relative risks (shown in parentheses) were found in first cousins(1.29), second cousins(1.13), siblings(2.95), spouses(3), parents(5.66) and children(9.18).
The relative risk based on familial data for first and second cousins indicate significant familial contribution due to the large population, narrow confidence interval, and assumption that several biases such as referral, diet, and living environments that may appear in siblings and parents, are minimized. This study is unique because it contains a much larger population and more distant relatives than other publications such as the Rotterdam study. Since the medical records data set only spans ten years, multi–generational risk is more difficult to calculate. The UPDB is a powerful tool to identify familial risk of AMD.
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