Effect of previous-winter mortality on the association between summer temperature and mortality in South Korea

Background

It has recently been postulated that low mortality levels in the previous winter may increase the proportion of vulnerable individuals in the pool of people at risk of heat-related death during the summer months.

Objectives

We explored the sensitivity of heat-related mortality in summer (June–August) to mortality in the previous winter (December–February) in Seoul, Daegu, and Incheon in South Korea, from 1992 through 2007, excluding the summer of 1994.

Methods

Poisson regression models adapted for time-series data were used to estimate associations between a 1°C increase in average summer temperature (on the same day and the previous day) above thresholds specific for city, age, and cause of death, and daily mortality counts. Effects were estimated separately for summers preceded by winters with low and high mortality, with adjustment for secular trends.

Results

Temperatures above city-specific thresholds were associated with increased mortality in all three cities. Associations were stronger in summers preceded by winters with low versus high mortality levels for all nonaccidental deaths and, to a lesser extent, among persons ≥ 65 years of age. Effect modification by previous-winter mortality was not evident when we restricted deaths to cardiovascular disease outcomes in Seoul.

Conclusions

Our results suggest that low winter all-cause mortality leads to higher mortality during the next summer. Evidence of a relation between increased summer heat-related mortality and previous wintertime deaths has the potential to inform public health efforts to mitigate effects of hot weather.     

High Temperature,Heat Index,and Mortality in 6 Major Cities in South Korea

The authors conducted a time-series analysis to estimate the acute effects of high temperature in 6 cities in Korea and to compare thresholds of temperature on daily mortality among the cities. They examined the association between total mortality and the daily mean temperature and heat index during the summers in Korea from 1994 to 2003. The threshold temperature was estimated to be between 27.0°C and 29.7°C for 4 cities. For a daily mean temperature increase of 1°C above the thresholds in Seoul, Daegu, Incheon, and Gwangju, estimated percentage increases in daily mortality were 16.3 (95% confidence interval [CI] = 14.2-18.4), 9.10 (CI = 5.12-13.2), 7.01 (CI = 4.42-9.66), and 6.73 (CI = 2.47-11.2), respectively. These city-specific threshold temperatures and the magnitude of the effects of hot temperature indicate that any analysis of the impact of climate change should take into account regional differences.     

Heat-Related Mortality and Adaptation to Heat in the United States

Background: In a changing climate, increasing temperatures are anticipated to have profound health impacts. These impacts could be mitigated if individuals and communities adapt to changing exposures; however, little is known about the extent to which the population may be adapting.Objective: We investigated the hypothesis that if adaptation is occurring, then heat-related mortality would be decreasing over time.Methods: We used a national database of daily weather, air pollution, and age-stratified mortality rates for 105 U.S. cities (covering 106 million people) during the summers of 1987–2005. Time-varying coefficient regression models and Bayesian hierarchical models were used to estimate city-specific, regional, and national temporal trends in heat-related mortality and to identify factors that might explain variation across cities.Results: On average across cities, the number of deaths (per 1,000 deaths) attributable to each 10°F increase in same-day temperature decreased from 51 [95% posterior interval (PI): 42, 61] in 1987 to 19 (95% PI: 12, 27) in 2005. This decline was largest among those ≥ 75 years of age, in northern regions, and in cities with cooler climates. Although central air conditioning (AC) prevalence has increased, we did not find statistically significant evidence of larger temporal declines among cities with larger increases in AC prevalence.Conclusions: The population has become more resilient to heat over time. Yet even with this increased resilience, substantial risks of heat-related mortality remain. Based on 2005 estimates, an increase in average temperatures by 5°F (central climate projection) would lead to an additional 1,907 deaths per summer across all cities.Citation: Bobb JF, Peng RD, Bell ML, Dominici F. 2014. Heat-related mortality and adaptation to heat in the United States. Environ Health Perspect 122:811–816; http://dx.doi.org/10.1289/ehp.1307392     

Racial Disparities in Diabetes Mortality in the 50 Most Populous US Cities

While studies have consistently shown that in the USA, non-Hispanic Blacks (Blacks) have higher diabetes prevalence, complication and death rates than non-Hispanic Whites (Whites), there are no studies that compare disparities in diabetes mortality across the largest US cities. This study presents and compares Black/White age-adjusted diabetes mortality rate ratios (RRs), calculated using national death files and census data, for the 50 most populous US cities. Relationships between city-level diabetes mortality RRs and 12 ecological variables were explored using bivariate correlation analyses. Multivariate analyses were conducted using negative binomial regression to examine how much of the disparity could be explained by these variables. Blacks had statistically significantly higher mortality rates compared to Whites in 39 of the 41 cities included in analyses, with statistically significant rate ratios ranging from 1.57 (95 % CI: 1.33–1.86) in Baltimore to 3.78 (95 % CI: 2.84–5.02) in Washington, DC. Analyses showed that economic inequality was strongly correlated with the diabetes mortality disparity, driven by differences in White poverty levels. This was followed by segregation. Multivariate analyses showed that adjusting for Black/White poverty alone explained 58.5 % of the disparity. Adjusting for Black/White poverty and segregation explained 72.6 % of the disparity. This study emphasizes the role that inequalities in social and economic determinants, rather than for example poverty on its own, play in Black/White diabetes mortality disparities. It also highlights how the magnitude of the disparity and the factors that influence it can vary greatly across cities, underscoring the importance of using local data to identify context specific barriers and develop effective interventions to eliminate health disparities.     

Modifiers of the temperature and mortality association in seven US cities

This paper examines effect modification of heat- and cold-related mortality in seven US cities in 1986-1993. City-specific Poisson regression analyses of daily noninjury mortality were fit with predictors of mean daily apparent temperature (a construct reflecting physiologic effects of temperature and humidity), time, barometric pressure, day of the week, and particulate matter less than 10 micro m in aerodynamic diameter. Percentage change in mortality was calculated at 29 degrees C apparent temperature (lag 0) and at -5 degrees C (mean of lags 1, 2, and 3) relative to 15 degrees C. Separate models were fit to death counts stratified by age, race, gender, education, and place of death. Effect estimates were combined across cities, treating city as a random effect. Deaths among Blacks compared with Whites, deaths among the less educated, and deaths outside a hospital were more strongly associated with hot and cold temperatures, but gender made no difference. Stronger cold associations were found for those less than age 65 years, but heat effects did not vary by age. The strongest effect modifier was place of death for heat, with out-of-hospital effects more than five times greater than in-hospital deaths, supporting the biologic plausibility of the associations. Place of death, race, and educational attainment indicate vulnerability to temperature-related mortality, reflecting inequities in health impacts related to climate change.     

High temperature, heat index, and mortality in 6 major cities in South Korea

The authors conducted a time-series analysis to estimate the acute effects of high temperature in 6 cities in Korea and to compare thresholds of temperature on daily mortality among the cities. They examined the association between total mortality and the daily mean temperature and heat index during the summers in Korea from 1994 to 2003. The threshold temperature was estimated to be between 27.0 degrees C and 29.7 degrees C for 4 cities. For a daily mean temperature increase of 1 degrees C above the thresholds in Seoul, Daegu, Incheon, and Gwangju, estimated percentage increases in daily mortality were 16.3 (95% confidence interval [CI] = 14.2-18.4), 9.10 (CI = 5.12-13.2), 7.01 (CI = 4.42-9.66), and 6.73 (CI = 2.47-11.2), respectively. These city-specific threshold temperatures and the magnitude of the effects of hot temperature indicate that any analysis of the impact of climate change should take into account regional differences.     

Local increases in coronary heart disease mortality among blacks and whites in the United States, 1985-1995

OBJECTIVES: This study analyzed coronary heart disease (CHD) mortality trends from 1985 to 1995, by race and sex, among Black and White adults 35 years and older to determine whether adverse trends were evident in any US localities. METHODS: Log-linear regression models of annual age-adjusted death rates provided a quantitative measure of local mortality trends. RESULTS: Increasing trends in CHD mortality were observed in 11 of 174 labor market areas for Black women, 23 of 175 areas for Black men, 10 of 394 areas for White women, and 4 of 394 areas for White men. Nationwide, adverse trends affected 1.7% of Black women, 8.0% of Black men, 1.1% of White women, and 0.3% of White men. CONCLUSIONS: From 1985 to 1995, moderate to strong local increases in CHD mortality were observed, predominantly in the southern United States. Black men evidenced the most unfavorable trends and were 25 times as likely as White men to be part of a local population experiencing increases in coronary heart disease mortality.     

Birthweight-specific infant mortality for native Americans compared with whites, six states, 1980.

We used data from the National Infant Mortality Surveillance (NIMS) project to compare birthweights and birthweight-specific mortality risks among Native American and White infants. Because race categories in NIMS were limited to White, Black, and all, we studied six states in which greater than 85 per cent of newborns who were neither White nor Black were Native American. In these states, the infant mortality risk (IMR) among Native Americans was 15.3 deaths per 1,000 live births compared with 8.7 deaths among Whites, relative risk (RR) = 1.8 (95% CI = 1.5-2.0). The percentage of Native American infants with less than 2,500 g birthweights was 5.8 per cent versus 5.0 per cent for White infants. Birthweight-specific neonatal mortality risks were similar for the two race groups, but birthweight-specific postneonatal mortality risks (PNMRs) were more than three times as high among Native Americans compared with Whites for infants of greater than or equal to 2,500 g birthweight. PNMRs were elevated for most causes of death and for all categories for maternal age, educational attainment, trimester prenatal care began, and number of previous live births. Leading causes of postneonatal death among Native Americans of greater than or equal to 2,500 g birthweight were sudden infant death syndrome and infections.     

Black-white disparities in elderly breast cancer mortality before and after implementation of Medicare benefits for screening mammography

BACKGROUND: Medicare implemented reimbursement for screening mammography in 1991. MAIN FINDINGS: Post-implementation, breast cancer mortality declined faster (p< .0001) among White than among Black elderly women (65+ years). No excess breast cancer deaths occurred among Black elderly compared with White elderly through 1990; over 2,459 have occurred since. Contextual socioeconomic status does not explain differences between counties with lowest Black breast cancer mortality/post-implementation declines in disparity and counties with highest Black breast cancer mortality/widened disparity post-implementation. CONCLUSIONS: The results lead to these hypotheses: (a) Medicare mammography reimbursement was causally associated with declines in elderly mortality and widened elderly Black:White disparity from breast cancer; (b) the latter reflects inherent Black-White differences in risk of breast cancer death; place-specific, unaddressed inequalities in capacity to use Medicare benefits; and/or other factors; (c) previous observations linking poverty with disparities in breast cancer mortality are partly confounded by factors explained by theories of human capability and diffusion of innovation.     

Rising Infant Mortality in Delaware: An Examination of Racial Differences in Secular Trends

Objectives: Recent increases in the Delaware Infant Mortality Rate (IMR) have been attributed to a rise in the mortality of very low birth weight (VLBW, <1500 g) infants born to mothers of higher socioeconomic status. This study examines whether the determinants of infant mortality trends in Delaware vary by race. Methods: Linked birth/infant death cohort files for the two periods 1993–1997 and 1998–2002 were used to evaluate the determinants of infant mortality trends separately for White and Black racial groups. Kitagawa analyses determined the components of race-specific infant mortality trends attributable to changes in both the birthweight distribution and birthweight-specific mortality rates. Maternal characteristics were examined to identify factors associated with IMR changes. Results: Between the two time periods, infant mortality increased 23% among White infants and 17% among Black infants. For both races, the infant mortality increase was explained by increases in the incidence and mortality of VLBW infants, specifically below <500 grams for Blacks and <1,000 grams for Whites. The increased incidence of VLBW deliveries was statistically significant only among Whites, almost 40% of which was explained by an increase in multiple births. For both Whites and Blacks, the increase in VLBW mortality occurred mainly among births to more traditionally advantaged women who were twenty or older, at least high school educated, married, privately insured, had received first trimester prenatal care, and those who delivered multiple births. Conclusions: These findings suggest that conventional strategies of increasing access to prenatal care among disadvantaged women may be insufficient to reverse recent IMR increases in Delaware, irrespective of race. Future efforts should focus on understanding the causes of the increased infant mortality associated with higher socioeconomic status, including changes in assisted reproductive technology utilization, maternal health status, and obstetric practice.     

Increased atrial fibrillation mortality: United States, 1980-1998

The authors used death certificate data to evaluate national trends in the reporting of atrial fibrillation as an underlying or contributory cause of death for groups defined by age (45 years or older), sex, and race (Black vs. White) and to examine comorbidity. The multiple-causes mortality files from 1980 through 1998 were analyzed for decedents, with atrial fibrillation (International Classification of Diseases, Ninth Revision, code 427.3) listed as one of up to 20 conditions causing death. The number of decedents with atrial fibrillation increased from 18,947 in 1980 to 61,946 in 1998, and the proportion with atrial fibrillation reported as the underlying cause of death rose from 8.3% in 1980 to 11.6% in 1998. Age-standardized death rates from 1980 to 1998 were consistently highest among White men, followed (in descending order) by White women, Black men, and Black women. Overall, the age-standardized rate (per 100,000) increased from 27.6 in 1980 to 69.8 in 1998 (an average annual increase of 5.4%, p < 0.0001). Ischemic heart disease was the most frequent underlying cause of death among decedents with atrial fibrillation (26.8%). These findings emphasize the need for increased application of proven prevention and control measures to decrease associated cardiovascular morbidity and mortality.     

The color of death: causes of death according to race in the State of Sao Paulo, 1999 to 2001

OBJECTIVE: Assuming that ethnicity might be a basis for social differentiation and that such differences might represent vulnerability to sickness, this study attempts to verify whether race or ethnic origin have an effect on mortality patterns. METHODS: The Sao Paulo State death register was examined from 1999 to 2001 in a contingence table of causes according to the 10th ICD and race or skin-color categories (White, Black, Mulatto and others). Chi-square test was used to check the association between skin-color and cause of death; residual analysis was used to elicit statistically significant excessive occurrences when each category of cause of death and skin color was combined; and correspondence analysis was used to examine overall relations among all categories considered. RESULTS: A total of 647,321 valid death registers were analyzed, among which 77.7% were of Whites, 5.4% of Blacks, 14.3% of Mulattoes and 2.6% of others. A significant association between skin color or race and cause of death was found. It may be observed that, although Blacks and Mulattoes present a similar death profile, on the contrary of Whites and others, which could be aggregated into a single category, the former appear in distinct positions on the multidimensional map presented. Except for mal defined causes, which characterize only the deaths of Blacks, the other causes of death within this group are common to both Blacks and Mulattoes, varying however, in intensity and as to the order in which they appear death. CONCLUSIONS: Analysis of mortality according to race or color revealed that death has a color. There is a White death, which has, among its causes, sicknesses, which, although variable, are nothing more than sicknesses. There's a Black death, which is not caused by sicknesses but by external causes, complications in labor and delivery, mental disorders and ill-defined causes.     

National maps of the effects of particulate matter on mortality: exploring geographical variation

In this paper, we present national maps of relative rates of mortality associated with short-term exposure to particulate matter < 10 micro m in aerodynamic diameter (PM(10)). We report results for 88 of the largest metropolitan areas in the United States from 1987 to 1994 for all-cause mortality, combined cardiovascular and respiratory deaths, and other causes of mortality. Maximum likelihood estimates of the relative rate of mortality associated with PM(10)and the degree of statistical uncertainty were obtained for each of the 88 cities by fitting a separate log-linear regression of the daily mortality rate on air pollution level and potential confounders. We obtained Bayesian estimates of the relative rates by fitting a hierarchical model that takes into account spatial correlation among the true city-specific relative rates. We found that daily variations of PM(10) are positively associated with daily variations of mortality. In particular, the relative rate estimates of cardiovascular and respiratory mortality associated with PM(10) are larger on average than the relative rate estimates of all-cause and other-cause mortality. The estimated increase in the relative rate of death from cardiovascular and respiratory mortality, all-cause mortality, and other-cause mortality were 0.31% (95% posterior interval, 0.15-0.5), 0.22% (95% posterior interval, 0.1-0.38), and 0.13% (95% posterior interval, -0.05 to 0.29), respectively. Bayesian estimates of the city-specific relative rates ranged from 0.23% to 0.35% for cardiovascular and respiratory mortality, from 0.18% to 0.27% for all causes, and from 0.10% to 0.20% for other causes of mortality. The spatial characterization of effects across cities offers the potential to identify factors that could influence the effect of PM(10) on health, including particle characteristics, offering insights into mechanisms by which PM(10) causes adverse health effects.     

Are race and length of gestation related to age at death in the sudden infant death syndrome?

Summary. Although race and preterm delivery are known to be associated with sudden infant death syndrome (SIDS), the relationships between age at death from SIDS and these factors have not been well described. To examine these relationships, we used linked infant birth and death records for the cohort of 1 204 375 White and 283 776 Black postneonates who were born from 1979 to 1981 in five states: California, Georgia, Missouri, South Carolina and Tennessee. Deaths attributable to SIDS occurred to 1404 White postneonates and to 696 Black postneonates. Although postneonatal SIDS rate among Black infants was twice that of White infants, the relative risk was smaller among infants with gestations of <35 weeks. For White postneonates, the median postneonatal age at death sharply declined for gestations from 28–29 weeks to 36–37 weeks and levelled off for longer gestations. For Black postneonates, the results do not support an association between length of gestation and age at death. The findings suggest that practitioners investigating approaches to avert SIDS need to maintain their interventions to an older age among White preterm infants. Researchers investigating the causes of SIDS need to consider the relationship between length of gestation and age at death from SIDS as well as possible developmental differences between White and Black preterm infants.     

Extreme temperatures and mortality: assessing effect modification by personal characteristics and specific cause of death in a multi-city case-only analysis

BACKGROUND: Extremes of temperature are associated with short-term increases in daily mortality. OBJECTIVES: We set out to identify subpopulations and mortality causes with increased susceptibility to temperature extremes. METHODS: We conducted a case-only analysis using daily mortality and hourly weather data from 50 U.S. cities for the period 1989-2000, covering a total of 7,789,655 deaths. We used distributions of daily minimum and maximum temperature in each city to define extremely hot days (>/= 99 th percentile) and extremely cold days (相似文献   

Racial and ethnic differences in perinatal mortality: the role of fetal death

PURPOSE: We investigate whether variations in infant mortality rates among racial/ethnic groups could be explained by variations in fetal mortality rates where relatively higher infant mortality rates may correspond to lower fetal mortality rates due to possible systematic differences in reporting of fetal death compared to live births. METHODS: Using US perinatal data from 1995 to 1999, we calculated crude mortality rates, birth weight-specific fetal and hebdomadal mortality rates, risks of perinatal death, and the risk of being classified as a fetal death versus other period death among infants born to Non-Hispanic White, Non-Hispanic Black, and Hispanic mothers. RESULTS: Two-fold disparities between Whites and Blacks persist for all mortality categories. Black low birth-weight deliveries, compared to Whites, have perinatal advantages in both fetal and hebdomadal periods. Hispanics were less likely than Whites to be reported as a fetal versus a hebdomadal death. CONCLUSIONS: While these data suggest some underreporting of Black fetal deaths, they provide little evidence that Black-White disparities in infant mortality are a function of variations in classifying a death occurring at delivery as either a fetal death or as a live birth-infant death. These data suggest that the lack of a White-Hispanic disparity in fetal mortality rates may be influenced by underreporting.     

Differences in physical activity between black and white girls living in rural and urban areas

This study examined the relationship of race and rural/urban setting to physical, behavioral, psychosocial, and environmental factors associated with physical activity. Subjects included 1,668 eighth-grade girls from 31 middle schools: 933 from urban settings, and 735 from rural settings. Forty-six percent of urban girls and 59% of rural girls were Black. One-way and two-way ANOVAs with school as a covariate were used to analyze the data. Results indicated that most differences were associated with race rather than setting. Black girls were less active than White girls, reporting significantly fewer 30-minute blocks of both vigorous and moderate-to-vigorous physical activity. Black girls also spent more time watching television, and had higher BMIs and greater prevalence of overweight than White girls. However, enjoyment of physical education and family involvement in physical activity were greater among Black girls than White girls. Rural White girls and urban Black girls had more favorable attitudes toward physical activity. Access to sports equipment, perceived safety of neighborhood, and physical activity self-efficacy were higher in White girls than Black girls.     

Racial disparity in pregnancy-related mortality associated with livebirth: can established risk factors explain it?

The authors conducted a nested case-control study to determine whether the fourfold increased risk of pregnancy-related mortality for US Black women compared with White women can be explained by racial differences in sociodemographic and reproductive factors. Cases were derived from a national surveillance database of pregnancy-related deaths and were restricted to White women (n = 840) and Black women (n = 448) whose pregnancies resulted in a livebirth and who died of a pregnancy-related cause between 1979 and 1986. Controls were derived from national natality data and were randomly selected White women and Black women who delivered live infants and did not die from a pregnancy-related cause (n = 5,437). Simultaneous adjustment for risk factors by using logistic regression did not explain the racial gap in pregnancy-related mortality. The largest racial disparity occurred among women with the lowest risk of pregnancy-related death: those of low to moderate parity who delivered normal-birth-weight babies (adjusted odds ratio = 3.53, 95% confidence interval: 2.9, 4.4). In contrast, no racial disparity was found among women with the highest risk of pregnancy-related death: high-parity women who delivered low-birth-weight babies. These findings indicate that reproductive health care professionals need to develop strategies to reduce pregnancy-related deaths among both high- and low-risk Black women.     

Race, asthma, and persistent wheeze in Philadelphia schoolchildren.

OBJECTIVES: Many studies show asthma to be more common in Black than in White children. This study assessed how much of this difference remains after adjustment for other potentially race-associated predictors of asthma. METHODS: We assessed the predictors of active diagnosed asthma and persistent wheeze in 1416 Black and White Philadelphia children aged 9 to 11 years, as reported by parents. RESULTS: Black race remained a significant predictor of active diagnosed asthma (odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.3, 4.1) but not of persistent wheeze (OR = 1.0; 95% CI = 0.6, 1.8). The excess risk of asthma in Black children was not appreciably altered by adjustment for other demographic and environmental factors. CONCLUSIONS: Black race is an important risk factor for active diagnosed asthma in these urban children, a relationship not explained by social factors. This finding and the lack of an association of race with persistent wheeze after adjustment for social factors suggest that race may be more important to the acquisition of an asthma diagnosis than to the prevalence of the symptoms.