Biomedical subjects

Jong-Tae Lee

Publications and source records attributed to Jong-Tae Lee.

6 recordsLinked to original sources

PubMed2003

Ischemic stroke associated with decrease in temperature.

BACKGROUND: Some studies suggest low temperatures can affect mortality, especially deaths associated with circulatory and respiratory conditions. METHODS: We investigated the association between ischemic stroke onset and decrease in temperature in 545 patients over a 3-year period (January 1998 to December 2000) in Incheon, Korea. We used a case-crossover study design to assess changes in the risk of ischemic stroke during a brief hazard period after exposure to decrease in temperature. For each subject, the case period was matched to 2 control periods exactly 1 week before and after onset of the ischemic stroke. RESULTS: Decreased ambient temperature was associated with risk of acute ischemic stroke. The strongest effect was seen on day after exposure to cold weather. The odds ratio (OR) for an interquartile range decrease in temperature was 2.9 (95% confidence interval [CI] = 1.5-5.3). The risk period was 24-48 hours after cold exposure. Risk estimates associated with decreased temperature were greater in the winter than in the summer. Women, persons greater than 65 years of age, nonobese persons, and those with previous hypertension or hypercholesterolemia were more susceptible to cold-induced ischemic stroke. CONCLUSIONS: These results suggest that stroke occurrence rises with decreasing temperature, and that even a moderate decrease in temperature can increase the risk of ischemic stroke. Susceptible people should take steps to protect themselves from cold, especially in the winter.

Age Factors↗

PubMed2003

Infant susceptibility of mortality to air pollution in Seoul, South Korea.

OBJECTIVE: Susceptibility of target populations to air pollution is an important issue, because air pollution policies and standards should be based on the susceptibilities of those at particular risk. To evaluate which age group is more susceptible to the adverse health effects of air pollution, we compared the effects of air pollution on mortality among postneonates, those aged 2 to 64 years, and those over 65 years of age. DESIGN: Daily counts of total and respiratory death along with daily levels of meteorological variables and air pollutants were analyzed using generalized additive Poisson regression. The relative risks (RR) of mortality for interquartile changes of the levels of particulate matter <10 micro m (PM(10)) were calculated on the same day. RESULTS: For postneonates, the RR of total mortality for an interquartile change (42.9 micro g/m(3)) in PM(10) (RR: 1.142; 95% confidence interval [CI]: 1.096-1.190) was greatest among age groups. Next were the elderly over 65 years of age (RR: 1.023; 95% CI: 1.022-1.024). Regarding respiratory mortality, RR for an interquartile change of PM(10) in postneonates (RR: 2.018; 95% CI: 1.784-2.283) was also greater than those in the other groups. CONCLUSIONS: These results agree with the hypothesis that infants are most susceptible to PM(10) in terms of mortality, particularly respiratory mortality.

Adolescent↗

PubMed2002

Association of air pollution with school absenteeism due to illness.

OBJECTIVE: To assess the association of air pollution and school absenteeism among elementary students. DESIGN: Time-series analysis of air pollution and school absenteeism data with controlling for long-term trends, seasonality, day of the week, and holiday as well as meteorologic variables. SETTING: School absenteeism data for the period from March 2, 1996, to December 22, 1999, were collected from student attendance reports of one elementary school in Seoul, Korea. MAIN OUTCOME MEASURES: The number of daily illness-related absences was analyzed against the daily levels of air pollution by generalized additive Poisson regression. The relative risks of absenteeism for air pollution exposure of interquartile ranges (the range from the lowest 25% of the value to the lowest 75% of the value) on absenteeism were calculated on the same day. RESULTS: Exposure to air pollutants such as particulate matter of 10 micro m or less in aerodynamic diameter (PM(10)), sulfur dioxide, and ozone, was associated with illness-related absenteeism. The estimated relative risks were 1.06 (95% confidence interval, 1.04-1.09) per 42.1- micro g/m( 3) increase in PM(10), 1.09 (95% confidence interval, 1.07-1.12) per 5.68-part per billion increase in sulfur dioxide, and 1.08 (95% confidence interval, 1.06-1.11) per 15.94-part per billion increase in ozone. There was no significant relationship between nitrogen dioxide level and illness-related absenteeism. CONCLUSION: Air pollution is associated with illness-related absences among elementary students.

Absenteeism↗

PubMed2002

Air pollution and asthma among children in Seoul, Korea.

BACKGROUND: As information about the health risks associated with air pollution has become available, attention has focused increasingly on susceptible persons such as children and persons with preexisting respiratory diseases, such as asthma. METHODS: We investigated the association between outdoor air pollution and asthma attacks among children under 15 years of age in Seoul, Korea. We estimated the relative risks of hospitalization associated with an interquartile range (IQR) increase in pollutant concentrations and used time series analysis of the counts by means of the generalized additive Poisson model. RESULTS: The estimated relative risk of hospitalization for asthma was 1.07 (95% confidence interval [CI] = 1.04-1.11) for particulate matters less than or equal to 10 microm in aerodynamic diameter (IQR = 40.4 microg/m3); 1.11 (95% CI = 1.06-1.17) for sulfur dioxide (IQR = 4.4 ppb); 1.15 (95% CI = 1.10-1.20) for nitrogen dioxide (IQR = 14.6 ppb); 1.12 (95% CI = 1.07-1.16) for ozone (IQR = 21.7 ppb); and 1.16 (95% CI = 1.10-1.22) for carbon monoxide (IQR = 1.0 ppm). CONCLUSIONS: These findings support the hypothesis that air pollution at levels below the current standards of Korea is harmful to sensitive subjects such as asthmatic children.

Adolescent↗

PubMed2002

Air pollution: a new risk factor in ischemic stroke mortality.

BACKGROUND AND PURPOSE: Air pollution is known to be associated with cardiovascular disease, but little is known about the occurrence of stroke in relation to air pollution. We investigated the association between acute stroke mortality and air pollution over a 7-year period (January 1991 through December 1997) in Seoul, Korea. METHODS: A generalized additive model was used to regress daily stroke death counts for each air pollutant, controlling for time trends, day of the week, and meteorological influences such as temperature, relative humidity, and atmospheric pressure. Ischemic and hemorrhagic stroke deaths were examined separately. RESULTS: The effects of air pollutants on ischemic stroke mortality were statistically significant, whereas this was not the case for hemorrhagic stroke mortality. We observed estimated relative risks of 1.03 (95% CI, 1.00 to 1.06) and 1.04 (95% CI, 1.01 to 1.08) for ischemic stroke mortality for each interquartile range increase in total suspended particulates and sulfur dioxide concentrations on the same day. We also found significantly increased relative risks of 1.04 (95% CI, 1.01 to 1.07) for nitrogen dioxide with a 1-day lag, of 1.06 (95% CI, 1.02 to 1.09) for carbon monoxide with a 1-day lag, and of 1.06 (95% CI, 1.02 to 1.10) for ozone with a 3-day lag for each interquartile range increase. CONCLUSIONS: These findings indicate that air pollutants are significantly associated with ischemic stroke mortality, which suggests an acute pathogenetic process in the cerebrovascular system induced by air pollution.

Air Pollution↗

PubMed2002

Effects of air pollutants on acute stroke mortality.

The relationship between stroke and air pollution has not been adequately studied. We conducted a time-series study to examine the evidence of an association between air pollutants and stroke over 4 years (January 1995-December 1998) in Seoul, Korea. We used a generalized additive model to regress daily stroke death counts for each pollutant, controlling for seasonal and long-term trends and meteorologic influences, such as temperature, relative humidity, and barometric pressure. We observed an estimated increase of 1.5% [95% confidence interval (CI), 1.3-1.8%] and 2.9% (95% CI, 0.3-5.5%) in stroke mortality for each interquartile range increase in particulate matter < 10 microm aerodynamic diameter (PM(10)) and ozone concentrations in the same day. Stroke mortality also increased 3.1% (95% CI, 1.1-5.1%) for nitrogen dioxide, 2.9% (95% CI, 0.8-5.0%) for sulfur dioxide, and 4.1% (95% CI, 1.1-7.2%) for carbon monoxide in a 2-day lag for each interquartile range increase in single-pollutant models. When we examined the associations among PM(10) levels stratified by the level of gaseous pollutants and vice versa, we found that these pollutants are interactive with respect to their effects on the risk of stroke mortality. We also observed that the effects of PM(10) on stroke mortality differ significantly in subgroups by age and sex. We conclude that PM(10) and gaseous pollutants are significant risk factors for acute stroke death and that the elderly and women are more susceptible to the effect of particulate pollutants.

Adolescent↗