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Youngjo Lee 2 Articles
Population-adjusted Mean Age at Incidence (PAMA) for Comparing Incidence Patterns with Age in Different Populations.
Yoon Ok Ahn, Moo Song Lee, Weechang Kang, Chung Min Lee, Youngjo Lee
Korean J Epidemiol. 1999;21(1):31-35.
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Abstract
Standardized incidence rates have been widely used for comparing incidence patterns between populations, adjusting for differences in demographic structure. These rates can compare overall incidence levels, but to fully understand incidence patterns, an index which links incidence with age is also needed. The authors proposed a statistical method for estimating population-adjusted mean age of incidence (PAMA), based on Poisson distribution and Fieller's theorem. The index was applied with several modifications to data relating to the incidence of breast cancer among Caucasian women living in Los Angeles.
Summary
A stochastic analysis on the force of infection by hepatitis B virus in Korea.
Keun Young Yoo, Moo Song Lee, Youngjo Lee, Bo Youl Choi, Heon Kim, Yong Sik Kim
Korean J Epidemiol. 1992;14(2):128-137.
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Abstract
Hepatitis B virus infection is still one of the major health problems in Korea, because of its high prevalence and its deleterious sequellae to liver cirrhosis and hepatocellular carcinoma. However, little is known about incidence (force of infection) of the viral infection. Investigation on the natural history of the virus, such as age-dependency of occurrence, is thus necessary to establish the efficient measures of prevention and management. This study was done to estimate the incidence of hepatitis B virus infection, as well as to assess the prevalent age group of the infection through a stochastic analysis using mathematical models. Data on positivity of hep¬atitis B virus markers (HBsAg, anti-HBs,anti-HBc) were obtained from two different population; a typical rural population in Kyunggi province (n=741) and a health insurance beneficiaries in the Seoul City (n=726). As results, force of infection by the virus was decreasing until the age group around 20, and afterwards remained stationary. The annual incidence of the infection was 15 per 100 persons at birth, 5 per 100 persons at the age, of 10, and about 3 per 100 persons after the age of 20. Proportion of antigen positivity among persons infected by the virus was also decreasing with age increasing. These results suggest that new infection of hepatitis B virus mostly occurs early in life in Korea, resulting in subsequent high prevalence of the infection.
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Epidemiol Health : Epidemiology and Health