Prevalence, incidence and modifiable factors for subtypes of mild cognitive impairment: results from the Longitudinal Ageing Study in China

Background: As the population in China rapidly ages, the prevalence of mild cognitive impairment (MCI) is increasing considerably. However, the causes of MCI vary. The continued lack of understanding of the various subtypes of MCI impedes the implementation of effective measures to reduce the risk of advancing to more severe cognitive diseases. Aims: To estimate the prevalence and incidence rates of two MCI subtypes-amnestic MCI (aMCI) and vascular cognitive impairment without dementia (VCIND)-and to determine modifiable factors for them among older individuals in a multiregional Chinese cohort. Method: This 1-year longitudinal study surveyed a random sample of participants aged≥60 years from a large, community-dwelling cohort in China. Baseline lifestyle data were self-reported, while vascular and comorbid conditions were obtained from medical records and physical examinations. In total, 3514 and 2051 individuals completed the baseline and 1-year follow-up assessments, respectively. Logistic and linear regression analyses were used to identify the modifiable factors for MCI subtypes and predictors of cognitive decline, respectively. Results: Among our participants, aMCI and VCIND demonstrated prevalence of 14.83% and 2.71%, respectively, and annual incidence (per 1000 person-years) of 69.6 and 10.6, respectively. The risk factor for aMCI was age, whereas its protective factors were high education level, tea consumption and physical activity. Moreover, VCIND risk factors were age, hypertension and depression. The presence of endocrine disease, cerebral trauma or hypertension was associated with a faster decline in cognition over 1 year. Conclusions: MCI is a serious health problem in China that will only worsen as the population ages if no widespread interventions are implemented. Preventive strategies that promote brain activity and support healthy lifestyle choices are required. We identified modifiable factors for MCI in older individuals. The easy-to-adopt solutions such as tea consumption and physical activity can aid in preventing MCI. Trial registration number: NCT03672448.