Nationwide Case-crossover Study Research Articles

Socioeconomic level and associations between heat exposure and all-cause and cause-specific hospitalization in 1,814 Brazilian cities: Anationwide case-crossover study.

Heat exposure, which will increase with global warming, has been linked to increased risk of a range of types of cause-specific hospitalizations. However, little is known about socioeconomic disparities in vulnerability to heat. We aimed to evaluate whether there were socioeconomic disparities in vulnerability to heat-related all-cause and cause-specific hospitalization among Brazilian cities. We collected daily hospitalization and weather data in the hot season (city-specific 4 adjacent hottest months each year) during 2000-2015 from 1,814 Brazilian cities covering 78.4% of the Brazilian population. A time-stratified case-crossover design modeled by quasi-Poisson regression and a distributed lag model was used to estimate city-specific heat-hospitalization association. Then meta-analysis was used to synthesize city-specific estimates according to different socioeconomic quartiles or levels. We included 49 million hospitalizations (58.5% female; median [interquartile range] age: 33.3 [19.8-55.7] years). For cities of lower middle income (LMI), upper middle income (UMI), and high income (HI) according to the World Bank's classification, every 5°C increase in daily mean temperature during the hot season was associated with a 5.1% (95% CI 4.4%-5.7%, P < 0.001), 3.7% (3.3%-4.0%, P < 0.001), and 2.6% (1.7%-3.4%, P < 0.001) increase in all-cause hospitalization, respectively. The inter-city socioeconomic disparities in the association were strongest for children and adolescents (0-19 years) (increased all-cause hospitalization risk with every 5°C increase [95% CI]: 9.9% [8.7%-11.1%], P < 0.001, in LMI cities versus 5.2% [4.1%-6.3%], P < 0.001, in HI cities). The disparities were particularly evident for hospitalization due to certain diseases, including ischemic heart disease (increase in cause-specific hospitalization risk with every 5°C increase [95% CI]: 5.6% [-0.2% to 11.8%], P = 0.060, in LMI cities versus 0.5% [-2.1% to 3.1%], P = 0.717, in HI cities), asthma (3.7% [0.3%-7.1%], P = 0.031, versus -6.4% [-12.1% to -0.3%], P = 0.041), pneumonia (8.0% [5.6%-10.4%], P < 0.001, versus 3.8% [1.1%-6.5%], P = 0.005), renal diseases (9.6% [6.2%-13.1%], P < 0.001, versus 4.9% [1.8%-8.0%], P = 0.002), mental health conditions (17.2% [8.4%-26.8%], P < 0.001, versus 5.5% [-1.4% to 13.0%], P = 0.121), and neoplasms (3.1% [0.7%-5.5%], P = 0.011, versus -0.1% [-2.1% to 2.0%], P = 0.939). The disparities were similar when stratifying the cities by other socioeconomic indicators (urbanization rate, literacy rate, and household income). The main limitations were lack of data on personal exposure to temperature, and that our city-level analysis did not assess intra-city or individual-level socioeconomic disparities and could not exclude confounding effects of some unmeasured variables. Less developed cities displayed stronger associations between heat exposure and all-cause hospitalizations and certain types of cause-specific hospitalizations in Brazil. This may exacerbate the existing geographical health and socioeconomic inequalities under a changing climate.

Fracture risk increased by concurrent use of central nervous system agents in older people: Nationwide case-crossover study.

Multiple medication use among older patients is reported to increase fracture risk. But this association is unclear in different subgroups and has not been confirmed by a case-crossover study, which can eliminate measurable and unmeasurable time-invariant confounders. To estimate the fragility fracture risk associated with concurrent use of multiple central nervous system (CNS) agents in older patients using a case-crossover design. This study targeted almost all patients aged ≥65 years in Japan who incurred fragility fractures from May 2013 to September 2014, based on the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB Japan). Conditional logistic regression analysis estimated the risk of fragility fracture associated with the daily number of CNS agents, including subgroup analyses stratified by sex, age, and fracture location. For 446,101 patients, the adjusted odds ratios (ORs) of fragility fracture increased almost linearly with number of CNS agents; 0, 0-1, 1-2, 2-3, 3-4, 4-5, and >5: OR reference, 1.21 (95% confidence interval, 1.18-1.23), 1.40 (1.35-1.46), 1.58 (1.49-1.67), 1.89 (1.74-2.05), 1.80 (1.60-2.03), and 1.90 (1.61-2.23; trend p<0.001), respectively. A similar trend was observed for several subgroups, especially in males and those aged ≥85 years, showing marked linearity. The increased risk of fragility fracture associated with the use of multiple CNS agents was robust in older people in Japan.

Antithrombotic medication and endovascular interventions associated with short-term exposure to particulate air pollution: A nationwide case-crossover study

Short-term exposure to air pollution has pro-thrombotic effects and triggers thrombo-embolic events such as myocardial infarction or stroke in adults. This study evaluates the association between short-term variation in air pollution and treatments for acute thrombo-embolic events among the whole Belgian population. In a bidirectional time-stratified case-crossover design, we included 227,861 events treated with endovascular intervention and 74,942 with antithrombotic enzymes that were reimbursed by the Belgian Social Security between January 1st, 2009 and December 31st, 2013. We compared the concentrations of particulate matter (PM) air pollution (PM10 and PM2.5), as estimated at the municipality level on the day of the event (lag 0) and two days earlier (lag 1 and lag 2) with those of control days from the same month, matched by temperature and accounting for day of the week (weekend vs week days). We applied conditional logistic regression models to obtain odds ratios (OR) and their 95% CI for an increase of 10 μg/m3 (PM10) or 5 μg/m3 (PM2.5) in pollutant concentrations over three lag days (lag 0, 1 and 2). We observed significant associations of PM10 and PM2.5 with treatment of acute thrombo-embolic events at the three lags. The strongest associations were observed for air pollution concentrations on the day of the event (lag0). Increases of 10 μg/m3 PM10 and 5 μg/m3 PM2.5 on lag0 increased the odds of events treated with endovascular intervention by 2.7% (95%CI:2.3%–3.2%) and 1.3% (95%CI:1%–1.5%), respectively, and they increased the odds of events treated with antithrombotic enzymes by 1.9% (95%CI:1.1–2.7%) and 1.2% (95%CI:0.7%–1.6%), respectively. The associations were generally stronger during autumn months and among children. Our nationwide study confirms that acute exposure to outdoor air pollutants such as PM10 or PM2.5 increase the use of medication and interventions to treat thrombo-embolic events.

Risk of stroke associated with intravitreal ranibizumab injections in age-related macular degeneration: a nationwide case-crossover study.

To evaluate the risk of stroke associated with intravitreal ranibizumab in age-related macular degeneration (AMD). A nationwide retrospective case-crossover study was performed using data from the Korean National Health Insurance Service (KNHIS) database, which included patients with exudative AMD in South Korea (n = 41,860). The index date was the date of hospitalization for stroke. We defined the case period as 60 days and four control periods before the index date. A pharmacy prescription database was searched for ranibizumab use during the case and control periods. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) with a conditional logistic regression model. A total of 865 patients with AMD and incident stroke were included. Of all the patients, 12.02% had been treated during the preceding 60-day case period, compared with 9.25-10.29% during control periods. The adjusted OR of stroke associated with intravitreal ranibizumab during the case period was 1.285 (95% CI 0.979-1.686) (p = 0.07). In the subgroup analysis, the risk of hemorrhagic stroke had an OR of 2.252 (95% CI 1.068-4.749, p = 0.033). Further analyses based on patient gender, age, and different risk periods of 15 and 30 days yielded no increase in the risk of stroke associated with intravitreal ranibizumab. This case-crossover analysis revealed no evidence of increased risk of hospitalization for stroke within 60 days of intravitreal ranibizumab injection in AMD patients. A secondary analysis indicated the possibility of an increased risk of hemorrhagic stroke, with borderline significance. Further research is needed regarding the underlying biological mechanisms and drug safety.

Short-term exposure to ambient fine particulate matter and out-of-hospital cardiac arrest: a nationwide case-crossover study in Japan

PM2·5 is an important but modifiable environmental risk factor, not only for pulmonary diseases and cancers, but for cardiovascular health. However, the evidence regarding the association between air pollution and acute cardiac events, such as out-of-hospital cardiac arrest (OHCA), is inconsistent, especially at concentrations lower than the WHO daily guideline (25 μg/m3). This study aimed to determine the associations between exposure to ambient air pollution and the incidence of OHCA. In this nationwide case-crossover study, we linked prospectively collected population-based registry data for OHCA in Japan from Jan 1, 2014, to Dec 31, 2015, with daily PM2·5, carbon monoxide (CO), nitrogen dioxide (NO2), photochemical oxidants (Ox), and sulphur dioxide (SO2) exposure on the day of the arrest (lag 0) or 1-3 days before the arrest (lags 1-3), as well as the moving average across days 0-1 and days 0-3. Daily exposure was calculated by averaging the measurements from all PM2·5 monitoring stations in the same prefecture. The effect of PM2·5 on risk of all-cause or cardiac OHCA was estimated using a time-stratified case-crossover design coupled with conditional logistic regression analysis, adjusted for daily temperature and relative humidity. Single-pollutant models were also investigated for the individual gaseous pollutants (CO, NO2, Ox, and SO2), as well as two-pollutant models for PM2·5 with these gaseous pollutants. Subgroup analyses were done by sex and age. Over the 2 years, 249 372 OHCAs were identified, with 149 838 (60·1%) presumed of cardiac origin. The median daily PM2·5 was 11·98 μg/m3 (IQR 8·13-17·44). Each 10 μg/m3 increase in PM2·5 was associated with increased risk of all-cause OHCA on the same day (odds ratio [OR] 1·016, 95% CI 1·009-1·023) and at lags of up to 3 days, ranging from OR 1·015 (1·008-1·022) at lag 1 to 1·033 (1·023-1·043) at lag 0-3. Results for cardiac OHCA were similar (ORs ranging from 1·016 [1·007-1·025] at lags 1 and 2 to 1·034 [1·021-1·047] at lag 0-3). Patients older than 65 years were more susceptible to PM2·5 exposure than younger age groups but no sex differences were identified. CO, Ox, and SO2 were also positively associated with OHCA while NO2 was not. However, in two-pollutant models of PM2·5 and gaseous pollutants, only PM2·5 (positive association) and NO2 (negative association) were independently associated with increased risk of OHCA. Short-term exposure to PM2·5 was associated with an increased risk of OHCA even at relatively low concentrations. Regulatory standards and targets need to incorporate the potential health gains from continual air quality improvement even in locations already meeting WHO standards. None.

Association between Heat Exposure and Hospitalization for Diabetes in Brazil during 2000-2015: A Nationwide Case-Crossover Study.

Background:Exposure to excessive heat, which will continue to increase with climate change, is associated with increased morbidity due to a range of noncommunicable diseases (NCDs). Whether this is true for diabetes is unknown.Objectives:We aimed to quantify the relationship between heat exposure and risk of hospitalization due to diabetes in Brazil.Methods:Data on hospitalizations and weather conditions were collected from 1,814 cities during the hot seasons from 2000 to 2015. A time-stratified case-crossover design was used to quantify the association between hospitalization for diabetes and heat exposure. Region-specific odds ratios (ORs) were used to calculate the attributable fractions (AFs).Results:A total of 553,351 hospitalizations associated with diabetes were recorded during 2000–2015. Every 5°C increase in daily mean temperature was associated with 6% [; 95% confidence interval (CI): 1.04, 1.07] increase in hospitalization due to diabetes with lag 0–3 d. The association was greatest (; 95% CI: 1.13, 1.23) in those of age, but did not vary by sex, and was generally consistent by region and type of diabetes. Assuming a causal association, we estimated that 7.3% (95% CI: 3.5, 10.9) of all hospitalizations due to diabetes in the hot season could be attributed to heat exposure during the study period.Discussion:Short-term heat exposure may increase the burden of diabetes-related hospitalization, especially among the very elderly. As global temperatures continue to rise, this burden is likely to increase. https://doi.org/10.1289/EHP5688

The association between heat exposure and hospitalization for undernutrition in Brazil during 2000-2015: A nationwide case-crossover study.

BackgroundGlobal warming is predicted to indirectly result in more undernutrition by threatening crop production. Whether temperature rise could affect undernutrition directly is unknown. We aim to quantify the relationship between short-term heat exposure and risk of hospitalization due to undernutrition in Brazil.Methods and findingsWe collected hospitalization and weather data for the hot season (the 4 adjacent hottest months for each city) from 1,814 Brazilian cities during 1 January 2000−31 December 2015. We used a time-stratified case-crossover design to quantify the association between heat exposure and hospitalization due to undernutrition. Region-specific odds ratios (ORs) were used to calculate the attributable fractions (AFs). A total of 238,320 hospitalizations for undernutrition were recorded during the 2000−2015 hot seasons. Every 1°C increase in daily mean temperature was associated with a 2.5% (OR 1.025, 95% CI 1.020−1.030, p < 0.001) increase in hospitalizations for undernutrition across lag 0–7 days. The association was greatest for individuals aged ≥80 years (OR 1.046, 95% CI 1.034−1.059, p < 0.001), 0–4 years (OR 1.039, 95% CI 1.024–1.055, p < 0.001), and 5–19 years (OR 1.042, 95% CI 1.015–1.069, p = 0.002). Assuming a causal relationship, we estimate that 15.6% of undernutrition hospitalizations could be attributed to heat exposure during the study period. The AF grew from 14.1% to 17.5% with a 1.1°C increase in mean temperature from 2000 to 2015. The main limitations of this study are misclassification of different types of undernutrition, lack of individual temperature exposure data, and being unable to adjust for relative humidity.ConclusionsOur study suggests that global warming might directly increase undernutrition morbidity, by a route other than by threatening food security. This short-term effect is increasingly important with global warming. Global strategies addressing the syndemic of climate change and undernutrition should focus not only on food systems, but also on the prevention of heat exposure.

Ambient heat and hospitalisation for COPD in Brazil: a nationwide case-crossover study

BackgroundHeat exposure has been related to increased morbidity and mortality for several health outcomes. There is little evidence whether this is also true for COPD. This study quantified the relationship...

1271Short-term effects of exposure to ambient fine particulate matter on out-of-hospital cardiac arrest: a nationwide case-crossover study in Japan

Abstract Introduction The cardiovascular health consequences of ambient air pollution generally equal or exceed those due to pulmonary diseases and cancers. Particulate matter less than 2.5μm in aerodynamic diameter (PM2.5) has become a major focus of research on the short-term exposure to air pollution and cardiovascular disease. However, the evidence regarding the association between several air pollutants and out-of-hospital cardiac arrest (OHCA), has been inconsistent, which could be due to limited sample sizes (∼11,000). Thus, a larger study may assist in characterising possible associations. Purpose This study aimed to identify the associations between exposure to ambient air pollution and the incidence of OHCA in Japan. Methods A case-crossover design was used to determine the odds ratio (OR) of OHCA across Japan with daily exposure of PM2.5, carbon monoxide (CO), photochemical oxidants (Ox), and sulfur dioxide (SO2) on the day of the arrest or 1–3 days before it (lag 0–3). OHCA cases were identified through the All-Japan Utstein registry of the Fire and Disaster Management Agency from January 1, 2014 to December 31, 2015. All cause OHCAs were investigated by conditional logistic regression adjusted for daily temperature and relative humidity. Results A total of 249,372 OHCAs were included during study period. Each 10 μg/m3 increase in daily PM2.5 exposure over 4 days was associated with all cause OHCA risk (lag 0: OR 1.017, 95% confidence interval (CI) 1.010, 1.024; lag 1: OR 1.015, 95% CI 1.008, 1.022; lag 2: OR 1.018, 95% CI 1.011, 1.025; lag 3: OR 1.021, 95% CI 1.014, 1.028; lag 0–1: OR 1.022, 95% CI 1.014, 1.030). CO, Ox and SO2 also showed significant associations with OHCAs. In the multi-pollutant model, the effects of PM2.5 remained independent of CO, Ox and SO2 (Table). Conclusion Short-term exposure to PM2.5 was independently associated with an increased risk of OHCA.

2284Sex and age differences in short-term exposure to ambient fine particulate matter and out-of-hospital cardiac arrest: a nationwide case-crossover study in Japan

Abstract Introduction Accumulating evidence has shown the elevated risk for cardiovascular diseases (CVD) with exposure to air pollution, such as fine particles &lt;2.5μm in aerodynamic diameter (PM2.5). A bi-directional relationship exists between air pollution and traditional CV risk factors like obesity, diabetes, and hypertension. However, little is known about the effect of age and sex on association between ambient air pollution and out-of-hospital cardiac arrest (OHCA). Purpose This study aimed to identify sex and age differences in the associations between exposure to PM2.5 and OHCA in Japan. Methods A case-crossover design was used to determine the odds ratio (OR) of OHCA across Japan with daily PM2.5 exposure on the day of the arrest or 1–3 days before it (lag 0–3). OHCA cases were identified through the All-Japan Utstein registry of the Fire and Disaster Management Agency from January 1, 2014 to December 31, 2015. OHCAs were investigated by conditional logistic regression adjusted for daily temperature and relative humidity with stratification by sex and age. Results A total of 249,372 OHCAs were included during study period. Their mean age was 75 years and 57% were male. Each 10 μg/m3 increase in daily PM2.5 exposure over 4 days was associated with all cause OHCA risk for male (lag 0: OR 1.022, 95% confidence interval (CI) 1.013, 1.031; lag 1: OR 1.016, 95% CI 1.007, 1.025; lag 2: OR 1.016, 95% CI 1.007, 1.026; lag 3: OR 1.017, 95% CI 1.008, 1.027; lag 0–1: OR 1.025, 95% CI 1.015, 1.036). Increased risk in OHCA was also found with lag 1 to lag 3 PM2.5 exposure among women. Lag 0 to lag 3 PM2.5 exposures were significantly associated with OHCA among patients older than 65 years. Among 35 to 64 years, only lag 3 PM2.5 exposure was associated with an increased risk in OHCA. No significant association was observed between PM2.5 exposure and OHCA among patients less than 35 years. Conclusions Short-term exposure to PM2.5 is associated with an increased risk of OHCA in both sexes. Patients older than 65 years were more susceptible to PM2.5 exposure than younger age group.

Oral short-acting antihypertensive medications and the occurrence of stroke: a nationwide case-crossover study

The purpose of the study was to clarify whether short-acting antihypertensives are associated with the occurrence of ischemic stroke and intracerebral hemorrhage (ICH). This was a retrospective case-crossover study using the Taiwan National Health Insurance Research Database. We identified all adult patients hospitalized with a primary diagnosis of ischemic stroke or ICH between January 2005 and December 2013. For each case, short-term and long-term exposure to short-acting antihypertensives, including nifedipine, labetalol and captopril, during the case vs. control periods were compared, and odd ratios (ORs) and 95% confidence intervals (CIs) for ischemic stroke or ICH were calculated with adjustment for confounders. Among 272785 ischemic stroke and 77798 ICH patients, the mean age was 77.8 ± 14.3 years and 70.8 ± 16.6 years, respectively. The short-term use of the three short-acting antihypertensives were all associated with an increase in the incidence of ischemic stroke (nifedipine: OR 4.51, 95% CIs 3.99-5.11; labetalol: OR 2.07; 95% CIs 1.71-2.51; captopril: OR 1.98, 95% CIs 1.72-2.29) and ICH (nifedipine: OR 2.98, 95% CIs 2.30-3.84; labetalol: OR 2.37; 95% CIs 1.66-3.39; captopril: OR 2.48; 95% CIs 1.69-3.63). The long-term use of short-acting nifedipine for 30 days was associated with a modest increase in the risk for ischemic stroke (OR 1.86; 95% CIs 1.42-2.45). Overall, the short-term use of short-acting antihypertensives is associated with a modest increase in the incidence of stroke, and short-acting nifedipine is linked to a substantial rise in the incidence of ischemic stroke. The long-term use of short-acting nifedipine was also related to an increased incidence of ischemic stroke. Physicians should be cautious of prescribing these short-acting antihypertensives.

Fluoroquinolone use and serious arrhythmias: A nationwide case-crossover study

AimFluoroquinolones have been associated with life-threatening ventricular arrhythmias and even sudden cardiac death. We aimed to assess the temporal relationship of fluoroquinolone use and serious arrhythmias via a case-crossover analysis of a large cohort of serious arrhythmias patients. MethodsIn a national administrative database, we compare the distributions of fluoroquinolone exposure for the same patient across a 30-day period before the serious arrhythmia event and 5 randomly selected 30-day periods before the serious arrhythmia event. Odds ratios (ORs) and 95% Confidence Intervals (CIs) were estimated using conditional logistic regression analysis. ResultsFrom a total of 2 million participants, 7657 patients with serious arrhythmias were identified. Use of fluoroquinolones within the 30-day period before the event was significantly associated with increased risk for serious arrhythmia (OR:3.03, 95% CI:2.48, 3.71). The risk association was attenuated, but remained significant after adjustment for time-varying confounders (OR:1.48, 95% CI:1.18, 1.86). A consistent increase in risk of serious arrhythmia was observed for all time windows investigated (7 days, 14 days, 30 days, 60 days and 90 days). ConclusionsExposure to fluoroquinolones was substantially associated with serious arrhythmic events, independent of the temporal proximity of fluoroquinolone prescription.

Temperature variability and hospitalization for ischaemic heart disease in Brazil: A nationwide case-crossover study during 2000–2015

BackgroundPrevious studies have suggested a potential relationship between temperature variability (TV) and ischaemic heart disease (IHD) but the nature and strength differ between studies. We quantify the association between TV and risk of hospitalization for IHD across Brazilian regions and examine how the relationship varies across important population subgroups. MethodsData on hospitalization for IHD and meteorological parameters were collected from 1814 cities during 2000–2015. TV was defined as the standard deviation of daily minimum and maximum temperatures during exposure days. City-specific estimates were quantified using a time-stratified case-crossover approach, and then pooled at the national level using a random-effect meta-analysis. Stratified analyses were performed by region, sex and three age-groups. ResultsThere were 2,864,904 IHD hospitalizations during 2000–2015. The estimate of TV effect was strongest on 0–1 days' exposure: odds ratio was 1.019 [95% confidence interval (CI): 1.013–1.025] per 5 °C increase in TV. The relationship was stronger in men [1.025 (95%CI: 1.017–1.033)] than in women [1.011 (95%CI: 1.002–1.019)] and in successively older age groups [1.034 (95%CI: 1.018–1.050)]. Regional differences existed, with the association only apparent in the most ageing parts of Brazil. ConclusionsExposure to TV is associated with increased risk of hospitalization for IHD, particularly in men and in older age groups. Our findings add to the growing evidence regarding the potential impact of climatic factors on important health outcomes.

Risk of Heart Failure Hospitalization Associated With Cilostazol in Diabetes: A Nationwide Case-Crossover Study.

Background and Objective: It has been suggested to avoid cilostazol, the first-line therapy for peripheral arterial disease, in patients with congestive heart failure (HF). The objective of this study was to evaluate the risk of hospitalization for heart failure (HHF) associated with cilostazol use in the patients of diabetes mellitus.Methods: This case-crossover study retrieved records on diabetic patients > 20 years of age who were hospitalized for heart failure during the period of 2009–2011 from the Taiwan National Health Insurance Database. The “current” period was defined as 1–30 days prior to HHF whereas the 91–120 days prior to HHF served as the “reference” period. The exposure status just preceding the event is compared with exposure of the same person in one or more referent remote to the event. Adjusted odds ratios (OR) were used to estimate time-varying discordant exposure by the ratio of the number exposed to cilostazol only during the case period to the number exposed to cilostazol only during the control period.Results: A total of 47,506 diabetic patients were included in the analysis (average age: 72.7 ± 12.4, percentage of males: 48%). A total of 399 patients (0.84%) received cilostazol only in the current period, and 252 (0.53%) received cilostazol only in the reference period. After adjustment for other medications, a significant association was found between cilostazol and HHF (OR: 1.35, 95% CI: 1.14–1.59). After further adjustment for time-varying co-morbidities the ORs remained essentially the same. Sensitivity analyses using different definitions of control period (ranging from 31–60, 61–90, to 121–150 days before index date) yielded adjusted ORs of 1.43 (95% CI: 1.14–1.79), 1.31 (95% CI: 1.09–1.57) and 1.23 (95% CI: 1.06–1.44), respectively suggesting the robustness of our study findings.Conclusion: Use of cilostazol may be positively related to the risk of HHF. Further studies are warranted to explore the underlying mechanisms and to confirm the association.

Decreased Risk of Fragility Fractures associated with Statin Use in the Older Japanese Population: a Nationwide Case–crossover Study

Decreased Risk of Fragility Fractures associated with Statin Use in the Older Japanese Population: a Nationwide Case–crossover Study

Temperature variability and hospitalization for cardiac arrhythmia in Brazil: A nationwide case-crossover study during 2000–2015

BackgroundThere is growing recognition of a potential role for environmental and climatic factors in influencing cardiovascular risk. It has been speculated that temperature variability (TV) is a risk factor for cardiac arrhythmia but evidence is limited. ObjectiveTo quantify the geographic and demographic variations in the association between TV and hospitalization for cardiac arrhythmia in Brazil during 2000–2015. MethodsData on hospitalization for arrhythmia and weather conditions were collected from 1,814 cities. TV was calculated as the standard deviation of daily maximum and minimum temperatures during exposure days. A time-stratified case-crossover approach was applied to examine the city-specific association between TV and hospitalization for arrhythmia. City-specific estimates were pooled at the national and regional levels using a random-effect meta-analysis. Stratified analyses were conducted by sex, three age-groups (0–64, 65–74 and ≥75 years), and three arrhythmia subtypes (paroxysmal tachycardia, atrial fibrillation and flutter, and other arrhythmias). ResultsThere were 447,667 arrhythmia-related hospitalizations during 2000–2015. The odds ratio of hospitalization per 1 °C increase in TV peaked on 0–1 days’ exposure [1.012 (95% confidence interval: 1.010–1.015)]. There were no substantial differences in effect estimates of TV0-1 by region, age or sex, except for the non-significant association observed in the north. However, women were more affected by prolonged TV exposure than men. For the three arrhythmias subtypes, only paroxysmal tachycardia and other arrhythmias were sensitive to TV. Assuming a causal relationship, 35,813 (95%CI: 18,302−51,665) cases were attributable to TV0-1 in Brazil during 2000–2015, accounting for 8.0% (95%CI: 4.1–11.5%) of hospitalizations for cardiac arrhythmia. ConclusionsAt a population-level exposure to TV was associated with increased risk of arrhythmia-related hospitalization in Brazil, with the relationship equally distributed across most residents but varied by arrhythmia subtypes. Our findings add to the accumulating evidence-base that climatic factors can influence cardiovascular outcomes in populations.

Short-Term Nighttime Wind Turbine Noise and Cardiovascular Events: A Nationwide Case-Crossover Study from Denmark

The number of people exposed to wind turbine noise (WTN) is increasing. WTN is reported as more annoying than traffic noise at similar levels. Long-term exposure to traffic noise has consistently been associated with cardiovascular disease. Effects of short-term exposure are much less investigated due to little day-to-day variation of e.g. road traffic noise. WTN varies considerably allowing investigation of short-term effects of WTN on cardiovascular events.METHODS AND RESULTS:We identified all hospitalisations and deaths from stroke (16,913 cases) and myocardial infarction (MI) (17,559 cases) among Danes exposed to WTN between 1982 and 2013. We applied a time-stratified, case-crossover design. Using detailed data on wind turbine type and hourly wind data at each wind turbine, we simulated mean nighttime outdoor (10-10,000 Hz) and nighttime low frequency (LF) indoor WTN (10-160 Hz) over the 4 days preceding diagnosis and reference days. For indoor LF WTN between 10 and 15 dB(A) and above 15 dB(A), odds ratios (ORs) for MI were 1.27 (95% confidence interval (CI): 0.97-1.67; cases &amp;#61; 198) and 1.62 (95% CI: 0.76-3.45; cases &amp;#61; 21), respectively, when compared to indoor LF WTN below 5 dB(A). For stroke, corresponding ORs were 1.17 (95% CI: 0.95-1.69; cases &amp;#61; 166) and 2.30 (95% CI: 0.96-5.50; cases &amp;#61; 15). The elevated ORs above 15 dB(A) persisted across sensitivity analyses. When looking at specific lag times, noise exposure one day before MI events and three days before stroke events were associated with the highest ORs. For outdoor WTN at night, we observed both increased and decreased risk estimates.CONCLUSION:This study did not provide conclusive evidence of an association between WTN and MI or stroke. It does however suggest that indoor LF WTN at night may trigger cardiovascular events, whereas these events seemed largely unaffected by nighttime outdoor WTN. These findings need reproduction, as they were based on few cases and may be due to chance.

Full moon and traffic accident-related emergency ambulance transport: A nationwide case-crossover study

BackgroundSeveral studies have examined the association between environmental factors and traffic accidents. However, the role of a full moon in triggering emergency ambulance transport due to road traffic casualties is unclear. Thus, we aimed to examine whether a full moon contributes to the incidence of emergency transport due to road traffic crashes. MethodsWe acquired nationwide data on daily emergency transport due to road traffic crashes from all 47 prefectures of Japan from 2010 to 2014. We conducted a time-stratified case-crossover study using conditional Poisson regression to examine the relationship between the occurrence of a full moon and emergency transport due to road traffic crashes for each prefecture. Prefecture-level results were combined using a random-effects meta-analysis to evaluate nation-level estimates. ResultsThere were 842,554 cases of emergency transport due to road traffic crashes across 1826 nights (62 full moon nights: n = 29,584; 1764 control nights: n = 812,970). On days with a full moon, the pooled adjusted relative risk (RR) of emergency transport due to traffic accidents was 1.042 (95% confidence interval [CI], 1.021–1.063). Overall, 4.03% (95% CI: 2.06–5.93) of the cases (1192 cases) were attributable to full moon nights. Stratified analyses revealed a significant increase in emergency transport due to traffic accidents on full moon nights for males, people aged ≥40 years, and before midnight. ConclusionsFull moon nights are associated with an increase in the incidence of emergency transport due to road traffic crashes. These results indicate that public health strategies should account for full moon nights to decrease emergency transport due to traffic accidents.

Invasive Procedures Associated With the Development of Infective Endocarditis

BackgroundVarious invasive medical procedures might induce bacteremia and, hence, act as triggers for infective endocarditis. However, empirical data in humans on the potential dangers of invasive medical procedures in this regard are very sparse. Due to lack of sufficient data, it is currently debated whether the risk for endocarditis with medical procedures is substantial or rather negligible. ObjectivesThe purpose of this nationwide case-crossover study was to quantify the excess risk for infective endocarditis in association with invasive medical and surgical procedures. MethodsThe authors identified all adult patients treated for endocarditis in hospitals in Sweden between January 1, 1998, and December 31, 2011. The authors applied a case-crossover design and compared the occurrence of invasive medical procedures 12 weeks before endocarditis with a corresponding 12-week time period exactly 1 year earlier. The authors considered all invasive nondental medical procedures except for those that are likely to be undertaken due to endocarditis or sepsis or due to infections that could possibly lead to endocarditis. ResultsThe authors identified 7,013 cases of infective endocarditis during the study period. Among others, several cardiovascular procedures, especially coronary artery bypass grafting; procedures of the skin and management of wounds; transfusion; dialysis; bone marrow puncture; and some endoscopies, particularly bronchoscopy, were strongly associated with an increased risk for infective endocarditis. ConclusionsThis study suggests that several invasive nondental medical procedures are associated with a markedly increased risk for infective endocarditis.

Short-term nighttime wind turbine noise and cardiovascular events: A nationwide case-crossover study from Denmark

AimsThe number of people exposed to wind turbine noise (WTN) is increasing. WTN is reported as more annoying than traffic noise at similar levels. Long-term exposure to traffic noise has consistently been associated with cardiovascular disease, whereas effects of short-term exposure are much less investigated due to little day-to-day variation of e.g. road traffic noise. WTN varies considerably due to changing weather conditions allowing investigation of short-term effects of WTN on cardiovascular events. Methods and resultsWe identified all hospitalisations and deaths from stroke (16,913 cases) and myocardial infarction (MI) (17,559 cases) among Danes exposed to WTN between 1982 and 2013. We applied a time-stratified, case-crossover design. Using detailed data on wind turbine type and hourly wind data at each wind turbine, we simulated mean nighttime outdoor (10–10,000 Hz) and nighttime low frequency (LF) indoor WTN (10–160 Hz) over the 4 days preceding diagnosis and reference days. For indoor LF WTN between 10 and 15 dB(A) and above 15 dB(A), odds ratios (ORs) for MI were 1.27 (95% confidence interval (CI): 0.97–1.67; cases = 198) and 1.62 (95% CI: 0.76–3.45; cases = 21), respectively, when compared to indoor LF WTN below 5 dB(A). For stroke, corresponding ORs were 1.17 (95% CI: 0.95–1.69; cases = 166) and 2.30 (95% CI: 0.96–5.50; cases = 15). The elevated ORs above 15 dB(A) persisted across sensitivity analyses. When looking at specific lag times, noise exposure one day before MI events and three days before stroke events were associated with the highest ORs. For outdoor WTN at night, we observed both increased and decreased risk estimates. ConclusionThis study did not provide conclusive evidence of an association between WTN and MI or stroke. It does however suggest that indoor LF WTN at night may trigger cardiovascular events, whereas these events seemed largely unaffected by nighttime outdoor WTN. These findings need reproduction, as they were based on few cases and may be due to chance.