Estimation of the National Burden of Disease and Vulnerable Population Associated with Natural Disasters in Korea: Heavy Precipitation and Typhoon.

BACKGROUND: Despite its growing significance, studies on the burden of disease associated with natural disasters from the perspective of public health were few. This study aimed at estimating the national burden of disease associated with typhoons and torrential rains in Korea. METHODS: During the period of 2002-2012, 11 typhoons and five torrential rains were selected. Mortality and morbidities were defined as accentual death, injury and injury-related infection, and mental health. Their incidences were estimated from National Health Insurance Service. Case-crossover design was used to define the disaster-related excess mortality and morbidity. Disability-adjusted life years (DALYs) were directly assessed from excess mortality and morbidity. RESULTS: The burden of disease from typhoons increased with the intensity, with 107.7, 30.6, and 36.6 DALYs per 100,000 per event for strong, moderate, and weak typhoons, respectively. Burden of disease from torrential rains were 56.9, 52.8, and 26.4 DALYs per 100,000 per event for strong, moderate, and weak episodes, respectively. Mental disorders contributed more years lived with disability (YLDs) than did injuries in most cases, but the injury-induced YLDs associated with strong typhoon and torrential rain were higher than those of lower-intensity. The elderly was the most vulnerable to most types of disaster and storm intensities, and males younger than 65 years were more vulnerable to a strong torrential rain event. CONCLUSION: The intensity of torrential rain or typhoon was the strongest determinant of the burden of disease from natural disasters in Korea. Population vulnerable may vary depending on the nature and strength of the disasters.

Current and Projected Burden of Disease From High Ambient Temperature in Korea.

BACKGROUND: The objective of the present study was to estimate the current and projected burden of disease from high ambient temperature using population-based data sources of nationwide mortality and morbidity in Korea. METHODS: Disability-adjusted life years (DALY) were estimated using noninjury-related deaths, and cerebrovascular and cardiovascular diseases from recently released nationwide health and mortality databases. Years of life lost and years lost due to disability were measured based on the point prevalence and number of deaths during the study period. Future DALY attributable to heat waves were estimated from projected populations, and temperature predictions for the years 2030 and 2050 were under Representative Concentration Pathways (RCP) 4.5 and 8.5 with summertime temperatures above threshold. RESULTS: Relative risks (RR) of total mortality and of cardiovascular disease were 1.02 (95% CI, 1.01, 1.02) and 1.08 (95% CI, 1.06, 1.09) for each 1°C increase in temperature above threshold, respectively. The morbidity of heat-related disease was RR 1.67 (95% CI, 1.64, 1.68) for each 1°C increase in temperature above threshold. DALY for all-cause death were 0.49 DALY/1000 in 2011, 0.71 (0.71) DALY/1000 in 2030 and 0.77 (1.72) DALY/1000 in 2050 based on RCP 4.5 (RCP 8.5). DALY for cardio- and cerebrovascular diseases were 1.24 DALY/1000 in 2011, 1.63 (1.82) DALY/1000 in 2030, and 1.76 (3.66) DALY/1000 in 2050 based on RCP 4.5 (RCP 8.5). CONCLUSIONS: Future excess mortality due to high ambient temperature is expected to be profound in Korea. Efforts to mitigate climate change can provide substantial health benefits via reducing heat-related mortality.

Estimating the Prevalence of Treated Epilepsy Using Administrative Health Data and Its Validity: ESSENCE Study.

BACKGROUND AND PURPOSE: Few of the epidemiologic studies of epilepsy have utilized well-validated nationwide databases. We estimated the nationwide prevalence of treated epilepsy based on a comprehensive medical payment database along with diagnostic validation. METHODS: We collected data on patients prescribed of antiepileptic drugs (AEDs) from the Health Insurance Review and Assessment service, which covers the entire population of Korea. To assess the diagnostic validity, a medical records survey was conducted involving 6,774 patients prescribed AEDs from 43 institutions based on regional clusters and referral levels across the country. The prevalence of treated epilepsy was estimated by projecting the diagnostic validity on the number of patients prescribed AEDs. RESULTS: The mean positive predictive value (PPV) for epilepsy was 0.810 for those prescribed AEDs with diagnostic codes that indicate epilepsy or seizure (Diagnosis-E), while it was 0.066 for those without Diagnosis-E. The PPV tended to decrease with age in both groups, with lower values seen in females. The prevalence was 3.84 per 1,000, and it was higher among males, children, and the elderly. CONCLUSIONS: The prevalence of epilepsy in Korea was comparable to that in other East Asian countries. The diagnostic validity of administrative health data varies depending on the method of case ascertainment, age, and sex. The prescriptions of AEDs even without relevant diagnostic codes should be considered as a tracer for epilepsy.

Maternal Blood Manganese and Early Neurodevelopment: The Mothers and Children's Environmental Health (MOCEH) Study.

BACKGROUND: Manganese is an essential trace element and common component of water, soil, and air. Prenatal manganese exposure may affect fetal and infantile neurodevelopment, but reports on in utero manganese exposure and infant neurodevelopment are rare. OBJECTIVE: This study was conducted to investigate a relationship between maternal blood manganese level and neurodevelopment of infants at 6 months of age. METHODS: Data were obtained from the Mothers and Children's Environmental Health (MOCEH) birth cohort study. The study population included 232 pairs of pregnant women and their infants at 6 months of age. Maternal blood manganese was measured at term, just before delivery. Mental and psychomotor development in infancy was assessed at 6 months of age using the Bayley Scales of Infant Development. The relationship between maternal blood manganese level and the mental and psychomotor development indexes (MDI and PDI) was estimated for manganese modeled as a linear and as a categorical variable and using penalized splines for nonlinear modeling. RESULTS: Mean ± SD maternal blood manganese concentration was 22.5 ± 6.5 µg/L. After adjustment for potential confounders, blood manganese was used as a continuous variable in a linear and nonlinear model. Associations between maternal blood manganese and MDI and PDI scores followed an inverted U-shape dose-response curve after adjustment for potential confounders, with lower scores associated with both low and high blood concentrations [MDI: likelihood-ratio test (LRT) p = 0.075, PDI: LRT p = 0.038]. Associations of both outcomes with increasing blood manganese shifted from positive to negative at concentrations of 24-28 µg/L in this cohort of term, normal birth weight children. CONCLUSION: Although no cut-off point has been established to define manganese toxicity, both high and low blood manganese levels may be associated with neurobehavioral function in infants.

Clinical characteristics of patients with treated epilepsy in Korea: a nationwide epidemiologic study.

OBJECTIVE: Although a number of epidemiologic studies have been conducted on the prevalence and incidence of epilepsy around the world, only a few studies have investigated the clinical characteristics of patients with epilepsy in a population-based sample. The purpose of the present study was to describe the clinical characteristics of treated patients with epilepsy in Korea via a nationwide medical records survey. METHODS: The study population was obtained through a nationwide database registered to the Health Insurance Review and Assessment service. Patients were recruited from clinics and hospitals in each cluster according to region and referral level by random selection from a preallocated sample of patients. All patients were being treated with antiepileptic drug medication with or without a diagnosis code for epilepsy or seizure between January 2009 and December 2009. Among the 6,436 selected patients, 2,150 met the diagnostic criteria for epilepsy and were included in our survey on the clinical characteristics of patients who were with treated epilepsy. RESULTS: The proportion of male patients with epilepsy in this study was higher (1,226; 57.0%) than that of female patients. In addition, 10.6% of patients were first diagnosed with epilepsy in 2009, and 53.6% of patients experienced at least one seizure over the course of 2009; 78.1% were classified as having localization-related epilepsy, whereas 7.3% were considered to have generalized epilepsy. Thirty-five percent of patients were thus classified as idiopathic or cryptogenic cases. The most common cause of symptomatic epilepsy was trauma (10.0%), followed by stroke (9.6%), central nervous system (CNS) infection (5.7%), and hippocampal sclerosis (4.9%). SIGNIFICANCE: This is the first nationwide study of the clinical characteristics of treated epilepsy in Korea using a national database validated by medical records survey. The etiologies of epilepsy and epilepsy syndrome classifications were comparable to those previously reported in other developed countries.

The validity and reliability of characterizing epilepsy based on an external review of medical records.

OBJECTIVES: Our goal is to validate diagnosing and characterizing epilepsy based on a medical record survey by external reviewers. METHODS: We reviewed medical records from 80 patients who received antiepileptic drugs in 2009 at two hospitals. The study consisted of two steps; data abstraction by certified health record administrators and then verification by the investigators. The gold standard was the results of the survey performed by the epileptologists from their own hospital. RESULTS: The specificity was more than 90.0% for diagnosis and activity, and for new-onset seizures. The sensitivity was 97.0% or more for diagnosis and activity and 66.7-75.0% for new-onset epilepsy. This method accurately classified epileptic syndromes in 90.2-92.9% of patients, causes in 85.4-92.7%, and age of onset in 78.0-81.0%. Kappa statistics for inter-rater reliability and test-retest reliability ranged from 0.641-0.975, which means substantial to near-perfect agreement in all items. CONCLUSIONS: Our data suggest that epilepsy can be well identified by external review of medical records. This method may be useful as a basis for large-scale epidemiological research.

Burden of disease of multiple sclerosis in Korea.

OBJECTIVES: Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. There are few reports on the burden of disease of MS, worldwide. The authors aim to estimate burden of disease and estimate the epidemiologic indexes of MS in Korea using available epidemiologic data. METHODS: Epidemiologic indexes were computed using DISMOD II software based on prevalence from nationwide survey, incidence estimated from extrapolation, mortality from National Statistics Office, and duration of disease from literature as input indexes. We calculated disability-adjusted life year (DALY) as a measure of premature mortality and disability, equivalent to years of healthy life lost due to a given condition. RESULTS: The incidence of MS in Korea was 0.1 per 100,000, higher in female than in male. The highest incidence was estimated in the age group between 35 and 44 years in male and age group between 25 and 29 years in female. Total burden of disease of MS was 1,394 DALY, comprised of 292 (21%) years of life lost and 1,101 (79%) years lived with disability. The mean age at onset of MS was 33 years old in men and 32 years old in female. Estimated duration of disease was 35 years in men and 40 years in female. Most of the DALY of MS occurred in the adult population between 25 and 54 years of age. CONCLUSION: Although MS is a rare disease in Korea, most of the DALY arises from young people, which results in a major financial burden on the patient, family, health system and society.

Occupations and Parkinson's disease: a multi-center case-control study in South Korea.

OBJECTIVE: We performed a hospital based case-control study in South Korea (1) to clarify the role of occupational exposure, and especially manganese (Mn) exposure in the etiology of Parkinson's disease (PD) and (2) to discover the association between any occupations and PD. METHODS: We selected two groups, PD patient group (N1) and controls (N2). Three hundred sixty-seven consecutive outpatients with PD (177 men, 190 women) and 309 controls were interviewed about life style, past history, family history, education level, and occupational history etc. We employed a range of industrial categories as defined by section (the most broad category) and division (sub-category) of the Korea Standard Industry Code (KSIC) Manual. Along with KSIC, we also used the Korea Standard Classification of Occupations (KSCO) as proxies of occupational exposure. The odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for age, sex, smoking status, and education level are presented. RESULTS: As regarding the exposure to hazardous materials, especially Mn, more subjects in the control group than the PD patient group have worked in the occupations with potential exposure to Mn (P < 0.001). Ever having worked in 'agriculture, hunting, and forestry' section of industry was positively associated with PD (OR 1.88), and 'agriculture production crops (OR 1.96)' division of industry was positively associated with PD. On the other hand, ever having worked in the 'manufacturing (OR 0.56)', 'transportation (OR 0.28)' section of industry, and 'transporting (OR 0.20)' division of industry were negatively associated with PD. 'Drivers (OR 0.13)' division of occupation also was negatively associated with PD. CONCLUSIONS: To our knowledge, this is the first case-control studies to find an inverse relationship between 'transporting' or 'technicians like machinery engineers' as his/her longest job and PD risk. Because of this unexpected finding, our work should be replicated in various populations.

Occupations and Parkinson's disease: a case-control study in South Korea.

We performed a hospital based case-control study in the southeast region of Korea to clarify the role of occupational exposure, especially manganese (Mn), in the etiology of Parkinson's disease (PD) and to discover the association between any occupation and PD. 105 outpatients with PD and 129 neurological disease controls and 101 healthy controls were interviewed. We employed occupational and industrial categories as defined by Section (the most broad category) and Division (sub-category) of the Korea Standard Industry Code and the Korea Standard Classification of Occupations. There was not a significant association between exposure to hazardous materials, especially Mn and PD. There were not any occupations listed under the Section of Industry Classification as a significant risk factor or protective factor for PD. However, the 'clerk' occupation [Section] was positively associated with PD. There is a decreased risk for PD with a subject ever having worked in the 'agriculture, forestry and fishery' occupational group. Ever having worked in 'sales' also was negatively associated with PD. There were not any Divisions of Industry found as a significant risk factor or protective factor for PD. However, ever having worked in an 'agriculture' Division of Occupation was negatively associated with PD.