Impact of high, and low temperatures on lower respiratory infections in a changing climate from 1990 to 2019: a joinpoint regression analysis.

<bold>Background:</bold> The Lancet Countdown to Climate Change predicts that in the twenty-first century, climate change will pose the biggest threat to human health. The burden of lower respiratory infections attributed to high and low temperatures in recent years is yet unknown, though. <bold>Methods:</bold> Data regarding age-standardized mortality rates (ASMRs) and age-standardized rates of disability-adjusted life years (ASDRs) for lower respiratory infections attributed to non-optimal temperatures between 1990 and 2019 were gathered based on the Global Burden of Disease Study (GBD) 2019. Joinpoint regression analysis was used to evaluate the trends in lower respiratory infections. <bold>Results:</bold> Between 1990 and 2019, there was a global downward trend in the ASMRs of lower respiratory infections attributed to high [average annual percentage change (AAPC) = -2.5; 95% CI (−4.3, -0.8)] and low temperatures [AAPC = -2.7; 95% CI (−3.1, -2.2)]. Low and middle socio-demographic index (SDI) countries showed the same trend for both high and low temperatures. However, while there was no trend for low temperatures [AAPC = 0.1; 95% CI (−0.04, 0.3)], there was for high temperatures [AAPC = 1.9; 95% CI (1.3, 2.7)] in high SDI countries, which was the opposite of the worldwide trend. Additionally, the ASDRs in high SDI countries attributed to high temperatures exhibited an upward trend [AAPC = 1.0; 95% CI (0.5, 1.4)]; however, the contrary was observed for low temperatures [AAPC = -0.8; 95% CI (−0.9, -0.7)]. <bold>Conclusion:</bold> Countries with high SDI were more severely affected by global warming, as evidenced by the increasing burden of lower respiratory infections.