Mortality in first- and second-generation immigrants to Sweden diagnosed with type 2 diabetes: a 10 year nationwide cohort study

Abstract

Aims/hypothesis Non-Western immigrants to Europe are at high risk for type 2 diabetes. In this nationwide study including incident cases of type 2 diabetes, the aim was to compare all-cause mortality (ACM) and cause-specific mortality (CSM) rates in first- and second-generation immigrants with native Swedes. Methods People living in Sweden diagnosed with new-onset pharmacologically treated type 2 diabetes between 2006 and 2012 were identified through the Swedish Prescribed Drug Register. They were followed until 31 December 2016 for ACM and until 31 December 2012 for CSM. Analyses were adjusted for age at diagnosis, sex, socioeconomic status, education, treatment and region. Associations were assessed using Cox regression analysis. Results In total, 138,085 individuals were diagnosed with type 2 diabetes between 2006 and 2012 and fulfilled inclusion criteria. Of these, 102,163 (74.0%) were native Swedes, 28,819 (20.9%) were first-generation immigrants and 7103 (5.1%) were second-generation immigrants with either one or both parents born outside Sweden. First-generation immigrants had lower ACM rate (HR 0.80 [95% CI 0.76, 0.84]) compared with native Swedes. The mortality rates were particularly low in people born in non-Western regions (0.46 [0.42, 0.50]; the Middle East, 0.41 [0.36, 0.47]; Asia, 0.53 [0.43, 0.66]; Africa, 0.47 [0.38, 0.59]; and Latin America, 0.53 [0.42, 0.68]). ACM rates decreased with older age at migration and shorter stay in Sweden. Compared with native Swedes, first-generation immigrants with ≤ 24 years in Sweden (0.55 [0.51, 0.60]) displayed lower ACM rates than those spending >24 years in Sweden (0.92 [0.87, 0.97]). Second-generation immigrants did not have better survival rates than native Swedes but rather displayed higher ACM rates for people with both parents born abroad (1.28 [1.05, 1.56]). Conclusions/interpretation In people with type 2 diabetes, the lower mortality rate in first-generation non-Western immigrants compared with native Swedes was reduced over time and was equalised in second-generation immigrants. These findings suggest that acculturation to Western culture may impact ACM and CSM in immigrants with type 2 diabetes but further investigation is needed.

Insulin action and secretion independent of traditional risk factors predict new‐onset type 2 diabetes in Iraqi and Swedish born citizens – The MEDIM cohort study

“…We have previously reported that Middle Eastern and non‐western immigrants have an earlier diabetes onset 5 . In our study, we saw differences with a higher incidence and a shorter time until diabetes diagnosis for the Iraqi born group but we could not show that the differences were statistically significant; this was most likely due to lack of power.…”

“…It is known that migration and urbanisation are risk factors for type 2 diabetes 3 . Previous studies have shown that immigrants from the Middle East have a higher prevalence of type 2 diabetes, and 6–10 years earlier diabetes onset compared to Swedish born individuals 4,5 . Recognising predictors of type 2 diabetes in high‐risk populations is important for identifying proper preventive actions and to decrease the risk of developing type 2 diabetes and its complications.…”

Type 2 diabetes burden among migrants in Europe: unravelling the causal pathways

“…Evidence indicates that migrants develop type 2 diabetes 10-20 years earlier [9][10][11] and at a lower level of BMI [12,13] than Europeans. The United Kingdom (UK) Biobank cohort data, for example, show that, for the equivalent prevalence of diabetes at 30 kg/m 2 in European descent participants, BMI equated to 22.0 kg/m 2 in South Asians, 26.0 kg/m 2 in African descent populations and 24.0 kg/m 2 and 26.0 kg/m 2 , respectively, in Chinese women and Chinese men [12].…”

“…By contrast, more recent studies show lower mortality risks in migrants with diabetes compared with Europeans [ 28 ]. In a nationwide 10-year longitudinal study of type 2 diabetes in Sweden, the adjusted risk of all-cause mortality and cause-specific mortality (due to CVD or cancer) was lower in first-generation migrants born in the Middle East, Asia, Africa and Latin America compared with European Swedes [ 11 ]. However, second-generation migrants with type 2 diabetes, especially those with both parents born abroad, had a 28% higher risk of all-cause mortality than the European Swedes [ 11 ].…”

“…In a nationwide 10-year longitudinal study of type 2 diabetes in Sweden, the adjusted risk of all-cause mortality and cause-specific mortality (due to CVD or cancer) was lower in first-generation migrants born in the Middle East, Asia, Africa and Latin America compared with European Swedes [ 11 ]. However, second-generation migrants with type 2 diabetes, especially those with both parents born abroad, had a 28% higher risk of all-cause mortality than the European Swedes [ 11 ]. In another recent cohort study using Clinical Practice Research Datalink data from 383 general practices in England, the adjusted risks for mortality from CVD, cancer and respiratory diseases were lower in people of South Asian and African descent with diabetes compared with European with diabetes [ 28 ].…”