Factors leading to the trajectory of cognitive decline in middle-aged and older adults using group-based trajectory modeling: A cohort study

Currently, studies exploring factors associated with the cognition at some time point and no study identifying the trajectories of cognitive changes and factors might associate with the trajectories of cognitive changes in people. This study was to identify factors associated with the trend of cognitive decline in middle-aged and older people. In this cohort study, the data of 6954 subjects were collected from China Health and Retirement Longitudinal Survey database. Group-based trajectory modeling was applied for identifying three different trajectories of cognitive function change [high initial level and slow decline group (n = 1024), moderate initial level and moderate decline group (n = 2673) and low initial level and rapid decline (LRD) group (n = 3277)]. Univariate and multivariate logistic regression analysis was conducted to identify variables influencing factors of the trajectories of cognitive function in middle-aged and older people. The follow-up interval was 2 years from 2011 to 2015, and 3 years from 2015 to 2018 via face-to-face interview. High initial level and slow decline group versus LRD group, age (OR = 2.591, 95% CI: 1.962–3.421), gender (OR = 1.398, 95% CI: 1.133–1.725), education (OR = 0.051, 95% CI: 0.039–0.068), place of residence (OR = 2.768, 95% CI: 1.663–4.606), disabled (OR = 1.557, 95% CI: 1.189–2.039), family annual income (OR = 0.757, 95% CI: 0.618–0.929), sleep duration (OR = 1.266, 95% CI: 1.023–1.567), instrumental activity of daily living impairment (OR = 2.513, 95% CI: 1.947–3.245), community activities participation (OR = 0.611, 95% CI: 0.500–0.748), depression (OR = 1.471, 95% CI: 1.185–1.828), and systolic blood pressure (OR = 1.005, 95% CI: 1.001–1.009) were factors influencing the trajectories of cognitive function. Comparing moderate initial level and moderate decline group and LRD group, age (OR = 1.245, 95% CI: 1.052–1.474), gender (OR = 1.244, 95% CI: 1.062–1.458), education (OR = 0.244, 95% CI: 0.190–0.314), marital status (OR = 1.291, 95% CI: 1.079–1.546), place of residence (OR = 1.677, 95% CI: 1.358–2.071), disability (OR = 1.396, 95% CI: 1.180–1.652), smoking (OR = 1.249, 95% CI: 1.071–1.457), family annual income (OR = 0.863, 95% CI: 0.768–0.970), sleep duration (OR = 1.215, 95% CI: 0.973–1.541), instrumental activity of daily living impairment (OR = 1.309, 95% CI: 1.098–1.560), community activities participation (OR = 0.804, 95% CI: 0.718–0.900) and depression (OR = 1.383, 95% CI: 1.217–1.571) were factors associated with the trajectories of cognitive function changes. Middle-aged and older adults who had characteristics associated with increased risk of cognitive decline might be provided with timely interventions.