Associations of age at type 2 diabetes diagnosis with ethnicity and socioeconomic deprivation: observational study in 11.5 million people in England.

backgroundIn England, younger individuals with type 2 diabetes (T2D) are more likely to be from minority ethnic groups and from higher levels of socioeconomic deprivation as compared to older individuals with T2D. It remains unclear whether younger individuals from these groups are at a heightened risk of T2D, or whether the observed distribution of ethnicity, deprivation, and age among those with T2D reflects that of the general population.

methodsIn this cross-sectional study, we used the Clinical Practice Research Datalink to identify adults with newly-diagnosed T2D, matched to up to 5 individuals without, in England between Jan 2000-Mar 2021. We estimated the distribution of individuals with T2D across ethnic groups and deprivation quintiles by age at diagnosis, as compared to individuals without T2D. Proportion ratios were calculated by dividing the proportion with T2D from each ethnic/deprivation group by the proportion without T2D from the corresponding group.

resultsWe included 2,676,039 individuals with T2D and 8,987,347 without. Across age, the pattern in the proportions of individuals with T2D from each ethnic group closely resembled the patterns in individuals without T2D, although there were consistently higher proportions from Black, South Asian, and other ethnic groups, meaning that the proportion ratio of being from these groups (comparing with vs without T2D) was consistently > 1. Nevertheless, proportion ratios for Black or other ethnic groups generally increased with age, being more stable for South Asian ethnicity. The proportion ratios for White ethnicity were consistently < 1; however, the pattern was U-shaped across age. At most ages, White individuals with T2D were more likely to be from the most deprived quintile and less likely to be from the least deprived quintile compared to individuals without T2D. There was generally no associations between T2D status and deprivation in individuals from minority ethnic groups across age.

conclusionsOur findings suggest that minority ethnicity status is a consistent risk factor for T2D across all age groups, rather than being disproportionately elevated at younger ages. The varying associations between T2D and deprivation across ethnic groups requires further investigation, particularly to explore whether T2D may be underdiagnosed in individuals from minority ethnic groups who experience high levels of deprivation.