Diurnal temperature range and short-term mortality in large US communities

Abstract

Research has shown that diurnal temperature range (DTR) is significantly associated with mortality and morbidity in regions of Asia; however, few studies have been conducted in other regions such as North America. Thus, we examined DTR effects on mortality in the USA. We used mortality and environmental data from the National Morbidity Mortality Air Pollution Study (NMMAPS). The data are daily mortality, air pollution, and temperature statistics from 95 large US communities collected between 1987 and 2000. To assess community-specific DTR effects on mortality, we used Poisson generalized linear models allowing for over-dispersion. After assessing community-specific DTR effects on mortality, we estimated region- and age-specific effects of DTR using two-level normal independent sampling estimation. We found a significant increase of 0.27 % [95 % confidence intervals (CI), 0.24-0.30 %] in nonaccidental mortality across 95 communities in the USA associated with a 1 °C increase in DTR, controlling for apparent temperature, day of the week, and time trend. This overall effect was driven mainly by effects of DTR on cardiovascular and respiratory mortality in the elderly: Mortality in the above 65 age group increased by 0.39 % (95 % CI, 0.33-0.44 %) and 0.33 % (95 % CI, 0.22-0.44 %), respectively. We found some evidence of regional differences in the effects of DTR on nonaccidental mortality with the highest effects in Southern California [0.31 % (95 % CI, 0.21-0.42 %)] and smallest effects in the Northwest and Upper Midwest regions [0.22 % (95 % CI, 0.11-0.33 %) and 0.22 % (95 % CI, 0.07-0.37 %), respectively]. These results indicate a statistically significant association between DTR and mortality on average for 95 large US communities. The findings indicate that DTR impacts on nonaccidental and cardiovascular-related mortality in most US regions and the elderly population was most vulnerable to the effects of DTR.

What drives cold-related excess mortality in a south Asian tropical monsoon climate–season vs. temperatures and diurnal temperature changes

“…Furthermore, the authors suggest that an inflammatory nasal responses (Graudenz et al 2006) may result from sudden temperature changes. In this study, we found a small negative effect of DTR with increasing mortality at higher ranges (models adjusted for temperature) which correspond well with findings from other studies (Lim et al 2013; Lim et al 2014). …”

“…We hypothesised that diurnal changes in temperature are causing increases in mortality. Several recent studies have established a relationship between temperature and DTR in Asia and North America (Lim et al 2013; Lim et al 2012; Lim et al 2014; Ding et al 2015; Kan et al 2007). In Bangladesh, DTR shows a strong seasonal pattern with the highest ranges observed during the cold season and is highly correlated with temperature.…”

“…Large ranges of diurnal temperatures might put stress on the human organism as it might be difficult to adjust to a wider range of temperatures. Lim et al (Lim et al 2013; Lim et al 2014) argues that DTR is likely to increase heart rate and blood pressure and furthermore suggests that respiratory symptoms may be exacerbated by immune system depression (Bull 1980). Furthermore, the authors suggest that an inflammatory nasal responses (Graudenz et al 2006) may result from sudden temperature changes.…”

Mortality burden of diurnal temperature range and its temporal changes: A multi-country study

“…Diurnal temperature range (DTR, i.e., the intra-day temperature change) is a well-known risk factor of weather-related human health. Numerous studies have described a positive association between DTR and mortality (Cao et al 2009;Lim et al 2015;Tam et al 2009;Vutcovici et al 2014;Yang et al 2013a), and have reported that people who are elderly, less educated, female or have cardiovascular or respiratory disease are more susceptible to DTR than others (Kan et al 2007b;Lim et al 2012a;Yang et al 2013b). In addition, because the DTR has been reported as an important meteorological indicator closely related with global climate change (Braganza et al 2004;Kan et al 2007b;Yang et al 2013b), an in-depth investigation of the DTR-mortality relationship becomes important as it helps to assess the future health impact of climate change more comprehensively.…”

Characterization of temperature difference between the neighbouring days in China and its potential driving factors

“…The patterns of annual mean TDN indicate that the short‐time temperature variation is more severe in high latitude and altitude areas than those in low latitude and altitude areas. Meanwhile, another intra‐day indicator of temperature variation called diurnal temperature change (DTR; Lim et al , ; ; Zhou et al , ), which can be calculated as the maximum temperature subtracted by the minimum temperature within 1 day, is available. DTR is high in low latitudes for relatively large solar elevation angle changes within a day (Braganza et al , ; Shahid et al , ).…”