Prevalence, Demographic and Clinical Characteristics of Individuals with Early Onset Type 2 Diabetes in the USA: an NHANES Analysis 1999–2020

Early onset type 2 diabetes (T2D), diagnosed before age 40 years, is potentially more aggressive than later-onset disease and is increasing in prevalence globally. We examined the prevalence of early onset T2D in the USA and characterised this population. Data from the longitudinal series of NHANES cross-sectional surveys conducted between 1999 and 2020 were analysed retrospectively. The prevalence of diagnosed and undiagnosed early onset T2D was estimated across this period and the demographics, clinical characteristics and frequency of comorbidities in this population were described. Findings were compared with the US later-onset T2D population during the same period. The prevalence of diagnosed and undiagnosed early onset T2D increased from 1.42% (standard error 0.19) and 0.18% (0.09), respectively, during the 1999-2000 survey cycle to 1.72% (0.24) and 0.35% (0.06), respectively, during the 2017-2020 cycle. Compared with those with later-onset disease, participants with early onset T2D had a lower mean poverty-income ratio, were more likely to be Hispanic or have no health insurance and less likely to be non-Hispanic white or have private or Medicare insurance (all p < 0.05). Individuals with early onset T2D generally had a worse cardiometabolic profile, with higher mean glycated haemoglobin, Homeostatic Model Assessment for Insulin Resistance score, fasting insulin and glucose, body mass index and waist circumference but were less likely to have congestive heart failure, coronary heart disease, stroke, chronic kidney disease or cancer (all p < 0.05). All comparisons remained statistically significant after adjustment for T2D duration among participants with diagnosed T2D. These findings suggest that early onset T2D may disproportionately affect underserved populations with a higher likelihood of having cardiometabolic risk factors, suggesting a more aggressive disease that warrants the need for better diagnoses and treatment. Further research is needed to explore the potential link between cardiometabolic profile, risk of complications and longer-term cardiovascular outcomes in people with early onset T2D.