Clustering of Cardiometabolic Risk Factors and Dementia Incidence in Older Adults: A Cross-Country Comparison in England, the United States, and China

Background: There is mixed evidence for an association between cardiometabolic risk factors and dementia incidence. This study aimed to determine whether different latent classes of cardiometabolic conditions were associated with dementia risk in older adults across England, the United States, and China.

Methods: A total of 4 511 participants aged 50 and older were drawn from the English Longitudinal Study of Ageing (ELSA), 5 112 from Health and Retirement Study (HRS), and 9 022 from China Health and Retirement Longitudinal Study (CHARLS). Latent class analyses were performed across each data set utilizing 7 baseline cardiometabolic conditions: obesity, low high-density lipoprotein cholesterol, systolic and diastolic blood pressure, hyperglycemia, diabetes, and inflammation. Confounder-adjusted Cox proportional hazards regressions were conducted to estimate dementia incidence by cardiometabolic latent classes.

Results: Three similar cardiometabolic classes were identified across all countries: (i) "relatively healthy/healthy obesity," (ii) "obesity-hypertension," and (iii) "complex cardiometabolic." Across the 3 samples, a total of 1 230 individuals developed dementia over a median of 6.8-12.2 years. Among ELSA and HRS participants, the "complex cardiometabolic" group had a higher dementia risk when compared to the "healthy obesity" groups (England: adjusted hazard ratio [AdjHR] = 1.62 [95% confidence interval {CI} = 1.11-2.37]; United States: AdjHR = 1.31 [95% CI = 1.02-1.68]). However, in CHARLS participants, the "obesity-hypertension" group had a greater risk of dementia when compared to the "relatively healthy" group (AdjHR = 1.28 [95% CI = 1.04-1.57]).

Conclusion: This study provides evidence that in western populations, complex cardiometabolic clusters are associated with higher rates of dementia incidence, whereas in a Chinese sample, a different cardiometabolic profile seems to be linked to an increased risk of dementia.