Diabetes in migrant communities: a rising healthcare priority

As of 2023, an estimated 281 million people globally are international migrants—constituting approximately 3.6% of the world population, reflecting steady growth over the past years.1 Non-communicable diseases, including diabetes, disproportionately impact migrant and ethnic minority populations due to a combination of genetic, environmental and socioeconomic factors.2 Previous studies in the USA and Europe have shown that ethnic minority populations have two to six times higher rates of type 2 diabetes (T2D) compared with their host populations.3 4 Migrants from South Asia had the highest rate, with the pooled OR being nearly fourfold higher, followed by those from the Middle East, North Africa and South and Central America, compared with Europeans.4 5 Similar data have been reported from Australia.6

Epidemiological studies have also reported that migrants and ethnic minorities have a higher risk of chronic complications, including cardiovascular disease, kidney disease, neuropathy and retinopathy, compared with native residents.7 The increased rate of complications is attributed to genetics and the complex interactions between social determinants of health and healthcare barriers, including lack of regular healthcare access due to limited health insurance coverage, language barriers, psychological stressors and financial constraints.6–8 However, recent reports and meta-analyses have suggested that most ethnic differences in T2D outcomes diminish after adjusting for smoking, socioeconomic status and Body Mass Index (BMI). A meta-analysis by Ezzatvar et al9 reported minimal ethnic disparities in T2D-related complications and all-cause mortality compared with native residents. Moreover, some European studies have shown lower all-cause mortality in ethnic minorities with T2D compared with European-born populations.

A systematic review and meta-analysis by Beulens et al10 sought to examine the impacts of immigrant and ethnic disparities in T2D complications across European studies, examining both cross-sectional and prospective research. Outcomes examined included mortality, macrovascular and microvascular complications, and mental disorders. They report that out of 2901 references, 58 studies met inclusion criteria, which allowed them to pool data from 1.2 million individuals. Findings revealed that, compared with host populations, migrant ethnic minorities had a 30% lower risk of all-cause mortality (RR 0.70 (95% CI 0.63 to 0.77); I²=87%) and 28% lower risk of macrovascular complications (RR 0.72 (95% CI 0.58 to 0.88); I²=88%), except for South Asians who experienced a slightly elevated risk of major cardiovascular events. There were no differences in microvascular complications across ethnic groups but elevated risks for retinopathy and nephropathy among ethnic minorities compared with European host populations, ranging from slightly higher to one-and-a-half times higher risks (RR 1.50 (95% CI 1.14 to 1.96); I²=86%). No significant ethnic differences were found for mental health disorders.

The discrepancy between the meta-analysis by Beulens et al10 and previous studies in European populations suggests a diverse pattern of T2D complications among immigrant populations. It is hard to ascribe the causes of these differences as there is vast heterogeneity in immigrant minority groups, complications examined and contexts where the studies were conducted. Although most ethnic minority populations were at reduced risk of macrovascular complications and major adverse cardiovascular events (acute myocardial infarction, stroke and cardiovascular death) compared with native-born populations, South Asians had comparable or even higher risks of most macrovascular complications. Previous research has also shown mixed results, with some European studies suggesting lower mortality rates for ethnic minorities with T2D, which contrasts with trends observed elsewhere. This finding may point to the health immigrant effect that may change over time.11

In summary, this meta-analysis highlights the different risk levels for diabetes complications among migrant communities, with some facing a lower risk and others a higher risk. The study challenges the common belief that all immigrant populations are at high risk of diabetes complications and suggests implementing targeted healthcare interventions and policies to address ethnic disparities in T2D outcomes across diverse European populations. Additional research is needed to determine whether the duration of residence and acculturation impacts the prevalence of T2D and its related complications among migrant populations. Furthermore, we must investigate how healthcare professionals can optimize care delivery to reduce the risk of T2D complications in various ethnic groups.