Association between atherogenic index of plasma and dementia: A longitudinal observational study

Background Atherogenic index of plasma (AIP) is a novel biomarker for status of lipid metabolism, but the association between AIP and dementia remains unclear. Objective We aimed to investigate the association between AIP and dementia among people with different glycemic status. Methods From the China Health and Retirement Longitudinal Study, 5195 dementia-free adults aged ≥45 (mean age 62.15 ± 7.00 years; 2668 [51.36%] female) at baseline (2011–2012) were followed up until 2018 to detect incident dementia. Dementia was ascertained based on cognitive batteries and the Activity of Daily Living scale. AIP was calculated by the formula: log [triglyceride (mg/dL) / high-density lipoprotein cholesterol (mg/dL)] and tertiled as low, moderate, and high. Data were analyzed using logistic regression. Results During the follow-up, 716 (13.3%) participants developed dementia. In basic-adjusted model, higher AIP was dose-dependently associated with an increased risk of dementia (per 1-SD increment in AIP, odds ratio [OR]: 1.10, 95% confidence interval [CI]: 1.02, 1.20, p = 0.020), whereas the association was not significant in fully-adjusted model (OR: 1.07 [0.97, 1.18]; p = 0.158). Compared with low AIP group, the OR (95% CI) of dementia was 1.27 (1.01, 1.60) for high AIP. After stratification, the association between high AIP and dementia was significant among people with diabetes (OR: 1.97, 95% CI: 1.11, 3.49) and a significant multiplicative interaction between high AIP and glycemic status was found (p for interaction = 0.029). Conclusions High AIP is associated with higher risk of dementia, particularly among people with diabetes. Our findings suggested that AIP could serve as an early indicator of dementia.