Impact of abdominal obesity prevalence trends on dementia, cardiovascular disease, functional impairment, and mortality in older Chinese adults: A Markov scenario simulation, 2020–2050

BACKGROUND: Dementia, cardiovascular disease (CVD), and functional impairment (FI) often co-occur in aging populations, with abdominal obesity as a shared modifiable risk factor. The long-term impact of abdominal obesity on these comorbidities is unclear. We projected the 30-year burden of dementia, FI, and CVD in China under different trajectories of abdominal obesity prevalence. METHODS AND FINDINGS: We modeled three trajectories of abdominal obesity prevalence from 2020 to 2050 using data from the China Health and Nutrition Survey (2000-2015): continuation of the observed growth prevalence trend (persistent), stabilization at 2015 levels (optimal), and a 50% reduction in the growth rate (improved). Abdominal obesity was defined as a waist circumference of ≥90 cm for men and ≥85 cm for women. A Markov model was used to estimate occurrence of dementia, CVD, FI, and mortality among adults aged ≥65 years by sex and year. Under the persistent scenario, dementia cases were projected to rise to 37.8 million (95% uncertainty interval (UI) [36.7, 38.9]) by 2050, alongside 68.1 million (95% UI [66.7, 69.5]) cases of FI, 198.3 million (95% UI [196.5, 200.4]) CVD cases, and 17.6 million (95% UI [16.5, 18.7]) deaths. Compared with the persistent scenario, dementia and FI burdens increased under the optimal and improved scenarios by 2050, by 1396.0 thousand (95% UI [589.1, 2293.9]) and 711.4 thousand (95% UI [294.4, 1150.3]) for dementia, and by 2570.6 thousand (95% UI [1081.0, 4024.9]) and 1289.5 thousand (95% UI [569.5, 2034.2]) for FI, mainly due to reduced CVD mortality expanding the population at risk. These shifts are most pronounced among adults aged ≥80 years and women. For CVD, reductions in the number of cases were projected in the short term (by 2030), but these changes remain uncertain by 2050. Main limitations include the assumption that other risk factors remain unchanged, and the lack of modeling of multiple co-occurring dementia's risk factors. CONCLUSIONS: Abdominal obesity control may reduce CVD incidence and mortality, thereby shifting the disease burden toward dementia and FI due to increased longevity, highlighting the need for integrated, life-course public health strategies responsive to the patterns of dementia and its comorbidity in older people.