The association between diurnal temperature range and emergency room admissions for cardiovascular, respiratory, digestive and genitourinary disease among the elderly: a time series study.

OBJECTIVES

To evaluate the short-term effect of diurnal temperature range (DTR) on emergency room (ER) admissions among elderly adults in Beijing.

METHODS

After controlling the long-time and seasonal trend, weather, air pollution and other confounding factors, a semi-parametric generalized additive model (GAM) was used to analyze the exposure-effect relationship between DTR and daily ER admissions among elderly adults with different lag structures from 2009 to 2011 in Beijing. We examined the effects of DTR for stratified groups by age and gender, and conducted the modifying effect of season on DTR to test the possible interaction.

RESULTS

Significant associations were found between DTR and four major causes of daily ER admissions among elderly adults in Beijing. A 1 °C increase in the 8-day moving average of DTR (lag 07) corresponded to an increase of 2.08% (95% CI: 0.88%-3.29%) in respiratory ER admissions and 2.14% (95% CI: 0.71%-3.59%) in digestive ER admissions. A 1 °C increase in the 3-day and 6-day moving average of DTR (lag 02 and lag 05) corresponded to a 0.76% (95% CI: 0.07%-1.46%) increase in cardiovascular ER admissions, and 1.81% (95% CI: 0.21%-3.45%) increase in genitourinary ER admissions, respectively. The people aged 75 years and older were associated more strongly with DTR than the 65-74 age group. The modifying effect of season on DTR was observed and it was various in four causes.

CONCLUSIONS

This study strengthens the evidence that DTR is an independent risk factor for ER admissions among elderly persons. Some prevention programs that target the elderly and other high risk subgroups for impending large temperature changes may reduce the impact of DTR on people's health.