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Summary: Background: Dementia has become a major public health concern worldwide, but comprehensive assessments of dementia burden attributable to high body mass index (BMI) in China have not been done. Methods: We used a temporal-spatial Bayesian hierarchical model to estimated BMI levels based on 1.25 million Chinese. We estimated dementia burden attributable to high BMI by age, sex, year, and socioeconomic development in terms of deaths and years of life lost (YLLs) and assessed the effect of population ageing. Findings: The average age-standardised BMI was 24.58 kg/m2 and 24.15 kg/m2 for men and women in 2018, respectively. 12,901 (95% UI, 10,617–15,420) dementia deaths were attributable to high BMI in China in 2018, with 5417 deaths from man and 7421 deaths from woman. The attributable age-standardised YLL rates for dementia increased 27% from 2005 to 2018. The attributable age-standardised mortality rates increased with human development index. People aged 80 years and older had the highest attributable mortality rate, and the rate decreased with decreasing age. Population ageing was an important component of the increase in dementia death. Interpretation: The rapid increase and large inequality highlighted the urgent need for evidence-based policies and interventions. We therefore call for establishing stronger anti-dementia strategies to promote the healthy ageing. Funding: China National Key Research and Development Program, China National Science & Technology Pillar Program, and National Health Commission of the People's Republic of China.

Previous studies have documented the associations between short-term diurnal temperature range (DTR) exposure and cardiovascular disease (CVD) via time-series analyses. However, the long-term impacts of DTR through a population-based prospective cohort have not been elucidated thoroughly. This study aimed to quantify the longitudinal association of DTR exposure with all-cause mortality and CVD in a nationwide prospective cohort and, by extension, project future DTR changes across China under climate change. We included 22,702 adults (median age 56.1 years, 53.7% women) free of CVD at baseline from a nationwide cross-sectional study in China during 2012–2015, and examined three health outcomes during a follow-up survey in 2018–2019. We estimated the chronic DTR exposure as baseline annual mean daily maximum minus minimum temperature. The Cox proportional hazards regression was adopted to assess the multivariable-adjusted hazard ratio and its corresponding 95% confidence interval (95% CI). We employed 31 downscaled global climate models under two shared socioeconomic pathways for future projection. During the median follow-up period of ~5 years, 1096 subjects died due to all causes while 993 and 597 individuals developed fatal or nonfatal CVD and fatal or nonfatal stroke, respectively. The cumulative incidence rates of all-cause mortality, CVD, and stroke were 10.49, 9.45, and 5.64 per 1000 person-years, respectively. In the fully adjusted models, the risks for all-cause mortality, CVD, and stroke would increase by 13% (95% CI: 8–18%), 12% (95% CI: 7–18%), and 9% (95% CI: 2–16%) per 1 °C increment in DTR, respectively. Moreover, linear positive associations for the concentration–response curves between DTR and mortality and CVD were observed. We also found significantly greater DTR-related mortality risks among rural residents than their urban counterparts. The DTR changes featured a dipole pattern across China under a warming climate. The southern (northern) China would experience increased (decreased) DTR exposure by the end of 21st century. The present study indicates that chronic DTR exposure can exert long-term impacts on mortality and CVD risks, which may inform future public health policies on DTR-related susceptible population and regions.