Global burden study of lower respiratory infections linked to low temperatures: an analysis from 1990 to 2019.

Low temperature conditions have been linked to a heightened susceptibility to lower respiratory infections (LRIs). Yet, our comprehension of the LRIs' disease burden due to such conditions remains limited, especially when considering the diverse socio-demographic indexes (SDIs) and climate types across various nations and regions. We examined the variations over time and space in the impact of LRIs due to low temperatures across a diverse set of 204 nations and regions, each with unique SDIs and climate types, spanning the years 1990 to 2019. Data from the Global Burden of Disease Study 2019 was used for this retrospective analysis. The burden of LRIs attributable to low temperatures was estimated by stratifying by sex, age, country, climate type, and SDI, including age-standardized mortality rate (ASMR) and age-standardized disability-adjusted life year rate (ASDR). We employed Joinpoint models to compute the annual average percent changes (AAPCs) in order to evaluate the trends in LRIs burden due to low temperatures from 1990 to 2019. Furthermore, we utilized Poisson age-period-cohort models to forecast the global and income-specific trends in LRIs burden due to low temperatures for the period 2020-2044. Generalized additive mixed models were used to fit changes in the disease burden of different climate regions. The relationship between SDI and both ASMR and ASDR was determined using models grounded in Gaussian process regression. In general, since the year 1990, there has been a significant reduction in the worldwide impact of LRIs due to low temperatures. This decrease is particularly noticeable among infants and the elderly, as well as in regions with a boreal climate and those with an average SDI. In 2019, LRIs induced by low temperatures showed an ASMR of 2.2 (95% CI: 1.34, 3.07) and an ASDR of 53.73 (95% CI: 17.5, 93.22) for every 100,000 individuals. A global reduction was observed in the ASMR and ASDR for LRIs over the period from 1990 to 2019, showing a decrease of 60.27% and 77.5%, in that order. For ASMR and ASDR, the AAPC values were found to be - 3.3 (95% CI: - 3.4, - 3.1) and - 5 (95% CI: - 5.2, - 4.9), in that order. However, a contrasting pattern was observed in southern Latin America, where an increase was noted in the ASMR for LRIs induced by low temperatures [AAPC: 0.5; 95% CI: (0.3, 0.8)]. Low temperature has decreased as an environmental risk factor for LRIs globally over 30 years, especially in middle SDI regions and boreal climates, but remains important for infants and the elderly population.