Empirical evidence linking racial/ethnic differences in glycosylated hemoglobin levels (HbA1c) to cognitive function in midlife and early old age is limited. We use biomarker data from the Health and Retirement Study (HRS, 2006–2014), on adults 50–64 years at baseline (57–73 years by 2014), and fit multinomial logistic regression models to assess the association between baseline HbA1c, cognitive function (using Langa–Weir classifications) and mortality across 8 years. Additionally, we test for modification effects by race/ethnicity. In age- and sex-adjusted models high HbA1c level was associated with lower baseline cognition and higher relative risk ratios (RRR; vs. normal cognition) for cognitive impairment no dementia (CIND; RRR = 2.3; 95%CI = [1.38;3.84]; p < .01), and dementia (RRR = 4.00; 95%CI = [1.76;9.10]; p < .01). Adjusting for sociodemographic, behavioral risk factors, and other health conditions explained the higher RRR for CIND and attenuated the RRR for dementia by approximately 30%. HbA1c levels were not linked to the slope of cognitive decline, and we found no evidence of modification effects for HbA1c by race/ethnicity. Targeting interventions for glycemic control in the critical midlife period can protect baseline cognition and buffer against downstream development of cognitive impairment. This can yield important public health benefits and reductions in burdens associated with cognitive impairment, particularly among race/ethnic minorities who are at higher risk for metabolic diseases.

将糖化血红蛋白水平 (HbA1c) 的种族/民族差异与中年和早年认知功能联系起来的经验证据有限。我们使用来自健康与退休研究（HRS，2006-2014）的生物标志物数据，针对基线时 50-64 岁的成年人（2014 年为 57-73 岁），并拟合多项 Logistic 回归模型来评估基线 HbA1c 与认知能力之间的关联。 8 年的功能（使用 Langa-Weir 分类）和死亡率。此外，我们还测试了种族/民族的修改效果。在年龄和性别调整模型中，高 HbA1c 水平与较低的基线认知和较高的认知障碍（无痴呆）相对风险比（RRR；与正常认知）相关（CIND；RRR = 2.3；95%CI = [1.38;3.84] ]； p < .01) 和痴呆 (RRR = 4.00；95%CI = [1.76;9.10]； p < .01)。调整社会人口统计学、行为风险因素和其他健康状况可以解释 CIND 的 RRR 较高，并使痴呆症的 RRR 降低约 30%。 HbA1c 水平与认知能力下降的斜率无关，而且我们没有发现种族/民族对 HbA1c 产生影响的证据。在关键的中年时期进行针对性的血糖控制干预措施可以保护基线认知并缓冲认知障碍的下游发展。这可以产生重要的公共健康效益并减轻与认知障碍相关的负担，特别是对于代谢疾病风险较高的种族/族裔群体。