Objectives To quantify the impact of thermal effect of temperature on non-accidental mortality and years of life lost.

Methods Data of daily death, meteorology and air pollution in Changping District from 2014 to 2017 were collected. The relationship between daily average temperature and daily mortality and years of life lost (YLL) was fitted by distributed lag non-linear model (DLNM). The cumulative excess mortality rate and years of life lost of heat were examined using a distributed lag non-linear model.

Results The thermal effect was immediate, lasting for 4 days. Heat-related cumulative excess mortality rate of non-accidental mortality was 0.030%(0.011%, 0.049%) per 1℃ increase of temperature across lag 0~4 days, 0.020% (-0.005%, 0.046%) for male and 0.044% (0.014%, 0.073%) for female, 0.038% (0.002%, 0.075%) for people under 65 years old and 0.028%(0.005%, 0.050%) for over 65 years old, respectively. Heat-related years of life lost were 5.38 (1.76, 9.00) for all, 2.00 (-0.79, 4.79) for men, 3.04(0.67, 5.40) for women, 3.97 (0.76, 7.18) for people under 65 years old group, and 1.01 (-0.58, 2.60) for people over 65 years old group.

Conclusions The non-accidental mortality rate and life loss year were increased by heat, and the increase were more obvious for female and the people under 65 years. It is necessary to adopt early warning measures to protect susceptible populations.