Hypothetical Interventions on Risk Factors for Cognitive Impairment among Chinese Older Adults: An Application of the Parametric G-Formula

Abstract

The effects of psychosocial and dietary interventions on risk of cognitive impairment is not known. The aim of this study was to estimate the 10-year risks of cognitive impairment under hypothetical interventions of psychosocial factors and dietary intake among Chinese older adults. A sample of 7377 respondents aged 65 and over was drawn from the last four waves of the Chinese Longitudinal Healthy Longevity Survey from 2002 to 2011/2012. The parametric g-formula was used to estimate the risk of cognitive impairment under independent hypothetical interventions of social engagement, psychological well-being (PWB), dietary intake, and the joint interventions of their different combination. The observed risk of cognitive impairment was 20.08% (95% confidence interval (CI): 18.81, 21.07). The risk ratios (RR) of cognitive impairment under the hypothetical interventions on higher social engagement, eating fruits at least sometimes, eating vegetables at least sometimes, positive PWB were 0.72 (95% CI: 0.65, 0.82), 0.93 (95% CI: 0.89, 0.95), 0.98 (95% CI: 0.89, 1.00) and 0.99 (95% CI: 0.98, 0.99), respectively. The RR of joint intervention was 0.64 (95% CI: 0.58, 0.73). Hypothetical interventions on psychosocial factors such as social engagement and PWB, as well as fruits and vegetable intake, were beneficial to protect older adults from cognitive impairment.

Air quality improvement and incident dementia: Effects of observed and hypothetical reductions in air pollutant using parametric g‐computation

“…47 The g-computation method is very useful for simulating a hypothetical scenario to provide information for potential recommendations and to inform policy decisions. This method was used previously to evaluate chemical neurotoxic effects in early life, 48 the effects of lifestyle interventions on cog-nitive impairment and dementia risk in older adults, 22,23 or to look at the positive public health impact of air quality improvements especially on childhood lung-function development and asthma incidence. 49,50 In this study, we show that such an analytical approach can be particularly useful to compare different air pollution mitigation strategies and quantify the expected benefits in the context of longitudinal settings.…”

“…The g-formula methods are a class of causal inference methods based on standardization that can simulate different hypothetical dynamic interventions on the exposure of interest (16)(17)(18). Previous studies have used these approaches to simulate complex interventions (19)(20)(21) for various settings including blood-pressurelowering interventions and dementia (22,23).…”

“…[16][17][18] Previous studies have used these approaches to simulate complex interventions [19][20][21] for various settings including blood-pressure-lowering interventions and dementia. 22,23 In a context where >90% of people worldwide live in areas exceeding the World Health Organization (WHO) Guideline for healthy air and where the number of people living with dementia is projected to triple in the upcoming 30 years with the aging populations, 24 it is crucial to take a multifaceted approach to improve population health. Alongside was associated with a reduced risk of dementia including Alzheimer's disease.…”