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BACKGROUND AND AIM: Although seasonal variations in mortality have been recognised for a long time, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and t...

BACKGROUND AND AIM: Minimum mortality temperature (MMT) and MMT percentile (MMTP) are important indicators for human adaptation to climate. Several studies reported that the MMT and MMTP have chang...

Background: Previous literature suggests that higher ambient temperature may play a role in increasing the risk of suicide. However, no multi-country study has explored the shape of the association and the role of moderate and extreme heat across different locations. Objectives: We examined the short-term temperature–suicide relationship using daily time-series data collected for 341 locations in 12 countries for periods ranging from 4 to 40 y. Methods: We conducted a two-stage meta-analysis. First, we performed location-specific time-stratified case-crossover analyses to examine the temperature–suicide association for each location. Then, we used a multivariate meta-regression to combine the location-specific lag-cumulative nonlinear associations across all locations and by country. Results: A total of 1,320,148 suicides were included in this study. Higher ambient temperature was associated with an increased risk of suicide in general, and we observed a nonlinear association (inverted J-shaped curve) with the highest risk at 27°C. The relative risk (RR) for the highest risk was 1.33 (95% CI: 1.30, 1.36) compared with the risk at the first percentile. Country-specific results showed that the nonlinear associations were more obvious in northeast Asia (Japan, South Korea, and Taiwan). The temperature with the highest risk of suicide ranged from the 87th to 88th percentiles in the northeast Asian countries, whereas this value was the 99th percentile in Western countries (Canada, Spain, Switzerland, the UK, and the United States) and South Africa, where nearly linear associations were estimated. The country-specific RRs ranged from 1.31 (95% CI: 1.19, 1.44) in the United States to 1.65 (95% CI: 1.40, 1.93) in Taiwan, excluding countries where the results were substantially uncertain. Discussion: Our findings showed that the risk of suicide increased with increasing ambient temperature in many countries, but to varying extents and not necessarily linearly. This temperature–suicide association should be interpreted cautiously, and further evidence of the relationship and modifying factors is needed. https://doi.org/10.1289/EHP4898, This study was partly supported by the Global Research Lab (K21004000001-10A0500-00710) the Mid-Career Research grant (2019R1A2C1086194) of the National Research Foundation, the Ministry of Science, Information and Communication Technologies in South Korea; by the Medical Research Council UK (MR/M022625/1 and MR/R013349/1) and the Natural Environment Research Council (NE/R0093894/1) in the UK; by the National Institutes of Health/National Institute of Environmental Health Sciences–funded Health and Exposome Research Center at Emory (HERCULES) Center (P30ES019776) and the USEPA grant RD-83587201 in the United States; by the National Health Research Institute (NHRI-EM-106-SP03) in Taiwan; by the Environment Research and Technology Development Fund (S-14) of the Ministry of the Environment in Japan; by the Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine, School of Tropical Medicine and Global Health, Nagasaki University in Japan; by the Japan Society for the Promotion of Science (JSPS) Invitational Fellowships for Research (S18149) in Japan; and by the JSPS Grants-in-Aid for Scientific Research (KAKENHI; JP16K19773, JP19K17104, and 19H03900) in Japan.

There is strong experimental evidence that physiologic stress from high temperatures is greater if humidity is higher. However, heat indices developed to allow for this have not consistently predicted mortality better than dry-bulb temperature.We aimed to clarify the potential contribution of humidity an addition to temperature in predicting daily mortality in summer by using a large multicountry dataset.In 445 cities in 24 countries, we fit a time-series regression model for summer mortality with a distributed lag nonlinear model (DLNM) for temperature (up to lag 3) and supplemented this with a range of terms for relative humidity (RH) and its interaction with temperature. City-specific associations were summarized using meta-analytic techniques.Adding a linear term for RH to the temperature term improved fit slightly, with an increase of 23% in RH (the 99th percentile anomaly) associated with a 1.1% [95% confidence interval (CI): 0.8, 1.3] decrease in mortality. Allowing curvature in the RH term or adding terms for interaction of RH with temperature did not improve the model fit. The humidity-related decreased risk was made up of a positive coefficient at lag 0 outweighed by negative coefficients at lags of 1-3 d. Key results were broadly robust to small model changes and replacing RH with absolute measures of humidity. Replacing temperature with apparent temperature, a metric combining humidity and temperature, reduced goodness of fit slightly.The absence of a positive association of humidity with mortality in summer in this large multinational study is counter to expectations from physiologic studies, though consistent with previous epidemiologic studies finding little evidence for improved prediction by heat indices. The result that there was a small negative average association of humidity with mortality should be interpreted cautiously; the lag structure has unclear interpretation and suggests the need for future work to clarify. https://doi.org/10.1289/EHP5430.

BackgroundAttributable mortality risk for heat and cold has been investigated in Europe and North America. However, none so far has provided estimates for Latin American, with a whole temperature r...

BackgroundEpidemiological evidence on the short-term effects of ultrafine particles (UFP), with aerodynamic diameter

Background/AimLow and high temperatures have been associated with mortality risk. In addition, the temperature-mortality relationship is different across geographic locations and specific causes. T...

Background/Aim: Previous studies have shown that temperature-health associations are highly heterogeneous across populations living in different parts of the world. However, little is known about t...

Introduction: The evidence is limited for the impacts of temperature variability (TV) within or between days on mortality. In this study, we applied a novel method to calculate TV, and investigated...

Introduction. Epidemiological evidence on the associations between exposure to ultrafine particles (UFP), with electrical mobility diameters

Introduction Several studies provide future projections of the temperature-related mortality in single cities or countries, but few offer a systematic assessment across climates and populations usi...

Background: Dozens of studies link acute exposure to particulate matter (PM) air pollution with premature mortality and morbidity, but questions remain about which species and sources in the vast PM mixture are responsible for the observed health effects. Although a few studies exist on the effects of species and sources in U.S. cities, European cities—which have a higher proportion of diesel engines and denser urban populations—have not been well characterized. Information on the effects of specific sources could aid in targeting pollution control and in articulating the biological mechanisms of PM. Objectives: Our study examined the effects of various PM sources on daily mortality for 2003 through 2007 in Barcelona, a densely populated city in the northeast corner of Spain. Methods: Source apportionment for PM ≤ 2.5 μm and ≤ 10 µm in aerodynamic diameter (PM2.5 and PM10) using positive matrix factorization identified eight different factors. Case-crossover regression analysis was used to estimate the effects of each factor. Results: Several sources of PM2.5, including vehicle exhaust, fuel oil combustion, secondary nitrate/organics, minerals, secondary sulfate/organics, and road dust, had statistically significant associations (p < 0.05) with all-cause and cardiovascular mortality. Also, in some cases relative risks for a respective interquartile range increase in concentration were higher for specific sources than for total PM2.5 mass. Conclusions: These results along with those from our multisource models suggest that traffic, sulfate from shipping and long-range transport, and construction dust are important contributors to the adverse health effects linked to PM. The study was funded, in part, by grant 200930I008 from the Spanish Council for Scientific Research and the Spanish Ministry of Science and Innovation (projects VAMOS CGL2010-19464/CLI and GRACCIECSD2007-00067)

Introduction: While several studies report estimates of heat or cold-mortality relationships, few have directly compared the burden attributable to different temperature components. Methods: Two-st...

Introduction: A number of studies have examined the variation in mortality risk associated to heat within the summer period. Here we investigate the issue in a large multi-country data set, applyin...

Introduction As global climate change proceeds, heatwaves will become more frequent, much longer and more intense. Thus, it is essential to assess health risks of heatwaves to better manage their h...

Introduction: Recent investigations have reported a decline in the heat-related mortality risk during the last decades. However, these studies are frequently based on modelling approaches that do n...

While few studies investigated the attributable mortality risk for either heat or cold in selected countries, none so far has provided estimates for the whole temperature range in different climate...

Background and Aims: Dozens of studies link acute exposure to particulate matter (PM) air pollution to premature mortality but questions remain about which species and sources in the PM mixture are...

Background and Aims: Winds from the Sahara desert transport large amounts of dust to Spain. The presence of high dust concentrations for long periods of time, and the interaction between dust and a...