Temperature-related emergency injury visits in Hanoi, Vietnam

Abstract

Background: The short-term association between increasing temperatures and injury has been described in high-income countries, but less is known for low-income and-middle-income countries, including Vietnam.

Methods: We used emergency injury visits (EIV) data for 2017-2019 from 733 hospitals and clinics in Hanoi, Vietnam to examine the effects of daily temperature on EIV. Time-series analysis with quasi-Poisson models was used to estimate a linear relative risk increase (RRI) for overall populations and ones stratified by age and sex. Exposure-response curves estimated non-linear associations as an RR between daily temperature and injury. Models were adjusted for the day of week, holidays, daily relative humidity, daily particulate matter, and long-term and seasonal trends.

Results and conclusions: A total of 39 313 EIV were recorded averaging 36 injuries daily. Injuries more likely occurred in males and those aged 15-44, and aged 44-60. For linear effects, a 5°C increase in same day mean temperature was associated with an overall increased EIV (RRI 4.8; 95% CI 2.3 to 7.3) with males (RRI 5.9; 95% CI 3.0 to 8.9) experiencing a greater effect than females (RRI 3.0; 95% CI -0.5 to 6.5). Non-linear effects showed an increase in EIV at higher temperatures compared with the threshold temperature of 15°C, with the greatest effect at 33°C (RR 1.3; 95% CI 1.2 to 1.6). Further research to investigate temperature-injury among different populations and by the cause of injury is warranted.

Keywords: Epidemiology; Public Health; Risk Factor Research; Time series.

Figure 1

Plot of non-linear exposure–response association curves between daily mean temperature and emergency injury visits for all, males and females. Shaded areas denote 95% CIs. Adjusted by day of week, holiday, RH, PM2.5 and time. Referencing temperature is at 15°C. PM2.5, particulate matter; RH, relative humidity; RR, relative risk.

Figure 2

Exposure–response curves between daily mean temperature and emergency injury visits by age and age groups stratified by gender. Shaded areas denote 95% CIs. Adjusted by day of week, holiday, RH, PM and time. Reference temperature is 15°C. PM2.5, particulate matter; RH, relative humidity; RR, relative risk.