Abstract
BACKGROUND: Prediabetes is an important risk factor of cardiovascular disease (CVD) and is associated with subclinical atherosclerosis. However, the evidence of prediabetes as a cardiovascular risk factor is mainly derived from middle-aged adults. Recently, multiple studies supported that prediabetes in older adults would not lead to higher risk of CVD or mortality. We aimed to investigate the age-specific difference in the association between prediabetes and subclinical atherosclerosis in a Chinese prospective cohort study. METHODS: We included 4739 individuals aged ≥ 40 years and without diagnosed diabetes or CVD history, and divided them into middle-aged adults (age < 60) and older adults (age ≥ 60). Fasting plasma glucose (FPG), 2-h post-load plasma glucose (2 h-PPG) and glycated hemoglobin (HbA1c) were measured at baseline to identify prediabetes status. At follow-up visits, subclinical atherosclerosis status was assessed by branchial-ankle pulse wave velocity (baPWV) and carotid intima-media thickness (CIMT). Logistic regression analysis, restricted cubic splines and cross-lagged path analysis were used in statistical analysis. RESULTS: 1634 participants aged over 60 years, and 64.3% of them had prediabetes. 3105 participants aged 40-59 years, and 49.3% of them had prediabetes. We found that prediabetes was associated with increased risk of subclinical atherosclerosis in middle-aged adults, but the association attenuated substantially in older adults. Impaired glucose tolerance (IGT), compared to normal glucose tolerance, was associated with 39% lower risk of increased baPWV only in older adults. In accordance, the association between 2 h-PPG and risk of increased baPWV was "U-shaped" in older adults, while risk of elevated baPWV increased linearly with 2 h-PPG in middle-aged adults. In the cross-lagged analysis, increase in FPG and 2 h-PPG tended not to precede increase in baPWV in older adults, but appeared to increase simultaneously with baPWV in middle-aged ones. CONCLUSION: Our results indicated that prediabetes might be less related to subclinical atherosclerosis in older adults than in middle-aged adults and suggested that age was important to consider in the care of adults with prediabetes.