Two-decade changes in dementia mortality in a Chinese community

Background

Evidence for the time trend of mortality with dementia from low- and middle-income countries is scarce.

Objective

To explore the secular trend of dementia mortality in a Chinese community over 2 decades.

Methods

The Shanghai Epidemiological Survey of Dementia and Alzheimer's Disease (SESD) and the Shanghai Aging Study (SAS) are community-based studies established in the same resident district in 1987 and 2010. We examined changes in 5-year mortality of dementia (i.e. Alzheimer's disease [AD], vascular dementia [VD], and all dementia) by analyzing survival data of participants aged≥65 years from the prospective stages of SESD (1987–1992) and SAS (2010–2015). Mortality rate (MR), case fatality rate (CFR), and standardized mortality ratio (SMR) in SAS were adjusted by the sex, age, and education-structured population data in SESD.

Result

The adjusted 5-year MRs of AD (0.76% vs. 2.24 %; OR, 95 %CI 0.34, 0.20–0.57), VD (0.37% vs. 1.16 %; OR 0.33,0.16–0.68), and all dementia (1.23% vs. 3.74 %; OR 0.32, 0.22–0.48) in SAS were lower than that in SESD. The same trend of the 5-year CFRs was also observed in AD (23.3% vs. 62.2 %; OR 0.19, 0.10–0.35), VD (48.7% vs. 77.4 %; OR 0.29, 0.10–0.90), and all dementia (61.0% vs. 70.6 %; OR 0.21, 0.12–0.35). The 2-year SMR in individuals with VD increased significantly (3.18 vs. 15.31), but the 5-year SMR increased gently (3.81 vs. 5.32) during the 2 decades.

Conclusion

We observed a decreasing trend of dementia mortality, and VD still induced a higher threat to life loss over 20 years in this older Chinese population.