Region-Based Analysis of Prevalence and Incidence of Parkinson's Disease: Analysis of the National Sample Cohort in South Korea

BACKGROUND AND PURPOSE: The rapid increases in the elderly population and urbanization in South Korea have influenced both demographics and the environment. This study investigated trends in the prevalence and incidence of Parkinson's disease (PD), and the associations of PD with the urban and rural environments in South Korea. METHODS: This study examined subjects aged 40 years or older in a cohort constructed using the National Sample Cohort data set in South Korea during 2002–2013. We estimated the age-standardized prevalence and incidence of PD based on the 2002 population, and estimated their trends. We analyzed regional differences in these rates by dividing South Korea into three regions based on geographic characteristics and two regions based on the degree of urbanization. RESULTS: The standardized prevalence rates of PD per 100,000 increased significantly from 75.8 in 2003 to 136.8 in 2012 (p 0.05). The standardized incidence of PD in younger subjects was lower in eastern Korea than in the other two regions, while in the older subjects it was lower in western Korea than in metropolitan Seoul over almost the entire analyzed period. The standardized incidence of PD did not differ significantly between metropolitan and nonmetropolitan areas. CONCLUSIONS: The standardized prevalence of PD increased steadily from 2003 to 2012 in South Korea, while its standardized incidence has remained constant. There were regional differences in the prevalence and incidence of PD based on the degree of urbanization and the area of agricultural land.

Small Area Spread of a New Type of infectious Condition across Berkshire in England between June 2011 and March 2013: Effect on Medical Emergency Admissions.

Aims: This study aims to investigate the small area spread of a presumed infectious agent, and to determine which factors determined the point of initiation, speed of the spread and the resulting increase in emergency medical admissions. Study Design: Analysis of a monthly time series of medical admissions using small area population aggregates of around 7,000 population contained within the census spatial unit called a Mid Super Output Area (MSOA). Place and Duration of Study: Emergency medical group admissions for residents of the six unitary authority locations in Berkshire, southern England between January 2008 and March 2013. Methodology: A running twelve month total of admissions was used to determine the point of initiation and the extent of a step-like increase in medical admissions. Results: Analysis shows evidence for spatial spread initiating around June 2011 through to March 2013. At onset, medical admissions increase and stay high for 12 to 18 months before beginning to abate. This spread commenced earlier among mainly Asian small areas (clustered from July 2011 onward) and later (clustered around March 2012) in predominantly affluent white areas. The observed percentage increase in admissions within the unitary authority areas varied from 25% to 51% (median value), however the average increase was highest as the geographic area became smaller, and this is suggested to arise from the aggregation of smaller social networks where the point of initiation of infectious spread occurs over time. The percentage increase in admissions displayed high single-year-of-age specificity suggestive of the immune phenomena called antigenic original sin, and is therefore suggestive of a different strain of an agent with previous outbreaks. The increase in emergency admissions showed a month-of-year pattern which appeared to follow the seasonal pattern of vitamin D levels in the blood. The presence of nursing homes, deprivation and ethnicity also has an effect on the average increase in admissions. Conclusion: It is suggested that all the above point to an outbreak of a previously uncharacterized type of infectious agent. There are profound implications regarding the use of standard five year age bands for the standardization of medical admission rates.

Unexpected Single-year-of-age Changes in the Elderly Mortality Rate in England and Wales During 2012.

Aims: To evaluate single-year-of-age specificity in deaths in England and Wales associated with a large, unexpected and unexplained increase in 2012. To demonstrate that this type of event has occurred previously across the entire UK. To demonstrate that infectious-like spread at a regional level in England may be involved. Study Design: Longitudinal study of annual (calendar year) deaths (all-cause mortality) in the United Kingdom and England and Wales using publically available statistics available from the Office for National Statistics (ONS). Place and Duration of Study: United Kingdom, England & Wales, local authorities within England & Wales covering a variety of time spans designed to illustrate various key points. Methodology: Deaths between 1974 and 2012 in the United Kingdom. Live population and deaths for residents of England and Wales and of English local authorities. Calculation of single-year-of-age death rates in 2011 and 2012 which are the years before and after the large and unexpected increase in deaths. Results: A recurring series of infectious-like events can be demonstrated which prior to 2000 had been largely assumed to be due to influenza epidemics. The event in 2012 shows specificity for the elderly particularly above age 75, which is somewhat expected given increased susceptibility to the environment as we age. The single year of age mortality rate shows saw tooth behavior for deaths in 2011 and even more exaggerated saw tooth behavior is seen in the difference between 2011 and 2012. Similar saw tooth behavior is seen in the difference between single-year-of-age standardized admissions via the emergency department in England between 2008 and 2012. The infectious spread across England behind this phenomenon is illustrated at regional level and probably results in a 40% underestimation of the saw tooth behavior. Conclusion: The saw tooth behavior is known to be associated with what is called ‘original antigenic sin’. Hence the saw tooth behavior appears to indicate that the unexpected high elderly mortality in 2012 was due to an outbreak of an infectious agent which has multiple strains. This behavior confirms the results of other studies investigating simultaneous increase in medical admissions to hospital during the time that the deaths increase. The ubiquitous herpes virus, cytomegalovirus may be involved, although at the moment this virus provides a prototype for the sort of immune modulating agent that may be responsible. The use of five year age bands to age standardize mortality and medical admission rates may be subject to misleading outcomes where the periodicity behind these outbreaks and their cumulative effect on immune mediated responses is out of synchrony with the basic saw tooth behavior seen in both mortality and admission rates. This has major implication to the calculation of hospital standardized mortality rates (HSMR).