Western culture erases protective immigrant effects in type 2 diabetes
medwireNews: New immigrants to a Western country have an initially reduced risk for mortality if they are diagnosed with type 2 diabetes, but this survival advantage is reversed across generations of exposure to the local culture, researchers report.
Louise Bennet (Lund University, Malmo, Sweden) told delegates at the virtual 56th EASD Annual Meeting that immigrants to Sweden were diagnosed with type 2 diabetes at a younger average age than the native population.
The average age at diagnosis was 60.6 years for native Swedes, 57.8 and 56.3 years for Western first- and second-generation immigrants, respectively, and 51.2 and 43.6 years for non-Western first- and second-generation immigrants, respectively.
First-generation Western immigrants with diabetes had similar mortality risks as Swedes with diabetes, but, despite their younger age at diagnosis, first-generation non-Western immigrants with diabetes had a significant 54% reduction in all-cause mortality risk and significant 63% and 30% reductions in risk for cardiovascular and cancer mortality. These associations were independent of age at diabetes diagnosis, sex, diabetes treatment, and sociodemographic factors.
Of note, the reduction in all-cause mortality risk among first-generation non-Western immigrants was 45% for those who had lived in Sweden for 24 years or less, but just 8% for those who had lived there longer, although this remained statistically significant.
By contrast, second-generation immigrants with diabetes had a significantly increased risk for all-cause mortality, although not for cardiovascular- or cancer-specific mortality. On further analysis, the increased risk was restricted to people with two foreign-born parents; they had a significant 28% increased mortality risk.
The 138,085 study participants were identified in national registries, were aged between 30 and 75 years, and had been prescribed glucose-lowering medications between 2006 and 2013. Most (74%) were native Swedes, 21% were first-generation immigrants, and 5% were second-generation immigrants.
Bennet suggested that new immigrants to Western countries may gain protection against mortality despite the presence of type 2 diabetes by sticking to their traditional diets, making them less prone to accumulate diabetic complications leading to early mortality.
In the case of second-generation immigrants, “we think that acculturation to the Western culture has a strong impact, together with socioeconomic factors,” she said, adding: “[A] big proportion are settled in socioeconomically vulnerable areas, [and these factors] together with gene–environment interactions can increase their risk of morbidity and mortality.”
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