Determining A1C Normal Values in Rhesus Macaques (Macaca mulatta)

Diabetes is a global health concern, with increasing prevalence attributed to factors such as obesity and sedentary lifestyles. Nonhuman primates (NHPs), particularly rhesus macaques (Macaca mulatta), serve as valuable models for studying type 2 diabetes mellitus due to their physiologic similarities to humans. However, there are currently no established normal ranges for glycated hemoglobin (A1C) in this species. This study aimed to determine normal A1C values in healthy, nonobese adult rhesus macaques to establish a reference for future diabetes research. A total of 210 Indian origin rhesus macaques (128 males, 82 females) 5-10 years of age were sampled. A1C was measured using the A1CNow+ kit, and blood glucose levels were assessed via a point-of-care glucometer and clinical laboratory analysis. Statistical analyses were performed using R, including a Shapiro-Wilks test for normality, regression analyses, and correlation coefficients. The mean A1C value was 5.92% (range, 4.4%-9.9%), with males exhibiting a mean of 6.07% and females 5.69%. No significant correlations were found between A1C and blood glucose levels, weight, body condition score, or age. However, males had significantly higher A1C levels than females (P = 0.004). Excluding outliers revealed a significant interaction between sex and weight (P = 0.03). The established mean A1C value for healthy adult rhesus macaques is higher than previously reported values for NHPs and human standards. This study provides a critical reference for A1C levels in rhesus macaques, facilitating future diabetes research and improving understanding of type 2 diabetes mellitus in both humans and NHPs.