Multimorbidity, lifestyle, and cognitive function: A cross-cultural study on the role of diabetes, cardiovascular disease, cancer, and chronic respiratory diseases

Background
The effect of lifestyle factors on cognitive function related to four major noncommunicable diseases (NCDs) including diabetes, cardiovascular disease, cancer, and chronic respiratory diseases, and the relationship between these NCDs and cognitive function have not been fully studied. We aimed to investigate the longitudinal associations between these NCDs and cognitive function in middle-aged and older people, and the combined effects of lifestyle factors.
Methods
By employing the data from three large-scale cohort studies from the U.S. Health and Retirement Study (2010–2019), English Longitudinal Study of Aging (2014–2019), and China Health and Retirement Longitudinal Study (2011–2019), this study carried out a multi-cohort analysis to 77, 210 participants. Fixed-effects regression models were used to examine associations between NCD status and cognitive function. Margin plots were used to illustrate the effect of lifestyle factors.
Results
Our findings revealed the dose-dependent association between mounting these NCDs and declining cognitive performance, ranging from one NCD (β = −0.05, 95 % CI: −0.08 to −0.02) to four NCDs (β = −0.51, 95 % CI: −0.75 to −0.28). Decline in cognitive function associated with NCDs was exacerbated with physical inactivity, current smoking status, and an increase in unhealthy lifestyle behaviors.
Limitations
The observational study design precludes causal interrogation of lifestyles and four NCDs on cognitive function.
Conclusions
An increasing number of these NCDs were dose-dependently associated with the decline in cognitive function score. Unhealthy lifestyle factors expedite decline in cognitive function linked to these NCDs.