Aims/hypothesis <p>Beyond longer diabetes duration, uncertainty remains regarding the factors that contribute to a higher risk of developing complications in younger vs older people with type 2 diabetes. We investigated whether younger age was associated with a more adverse risk-factor profile compared with older age among people with type 2 diabetes.</p> Methods <p>We conducted cross-sectional analyses of demographic and clinical data from individuals with type 2 diabetes participating in national health surveys from four countries: the Australian Diabetes, Obesity and Lifestyle Study (AusDiab), the US National Health and Nutrition Examination Survey (NHANES), the Mauritius Non-Communicable Diseases Survey (Mauritius Survey), and the Indian Council of Medical Research-India Diabetes (ICMR-INDIAB) study. Type 2 diabetes was defined according to each study’s criteria, including previously diagnosed and newly diagnosed (screen-detected) diabetes (NDM). Individuals with normal glucose tolerance (NGT) were included for comparison. Regression analyses with natural splines assessed association between age at survey and cardiometabolic risk factors in each cohort.</p> Results <p>There were 903 participants with type 2 diabetes from AusDiab, 7086 from NHANES, 2682 from the Mauritius Survey and 10,151 from ICMR-INDIAB. In three of the four studies (excluding ICMR-INDIAB), BMI decreased with increasing age. Younger individuals had higher low-density lipoprotein cholesterol (in NHANES and AusDiab) and lower high-density lipoprotein cholesterol (in all studies except ICMR-INDIAB) compared with older individuals. In AusDiab, NHANES and the Mauritius Survey, triglycerides were highest in younger adults, declining with age. In AusDiab, the Mauritius Survey and ICMR-INDIAB, fasting plasma glucose (FPG) increased with age until 45–55 years, after which it declined. In NHANES, younger individuals with diabetes had higher FPG than older individuals. In all four studies, haemoglobin A_1c (HbA_1c) increased with age, peaking around 50–60 years, before declining. In NDM, 2 h plasma glucose did not vary across age. Systolic blood pressure (SBP) and urinary albumin/creatinine ratio (UACR) were higher in older individuals. Comparing diabetes with NGT, differences in FPG, HbA_1c, triglycerides and diastolic blood pressure (DBP) were greater at younger than older ages in most cohorts. The same was observed for BMI and SBP, but only in two studies (AusDiab and NHANES).</p> Conclusions/interpretation <p>Younger individuals with type 2 diabetes have higher BMI and triglycerides (observed in three out of four studies) but lower SBP and UACR than older individuals with type 2 diabetes. FPG and HbA_1c peak in middle age. Differences relative to individuals without diabetes were more pronounced at younger than older ages for FPG, HbA_1c, triglycerides and DBP, and were possibly greater for BMI and SBP. These age-related patterns likely influence the overall risk of diabetes-related complications.</p> Graphical Abstract <p></p>