National and subnational analysis of self-reported diabetes mellitus and health inequalities in Europe

Diabetes mellitus (DM) has been a major public health concern with increased epidemiologic and economic burden in Europe. We aimed to estimate self-reported national and subnational DM prevalence and inequalities in individuals aged 50 years and over in 13 European countries between 2010 and 2019. Microdata were extracted from waves 4 (2010/2011), 5 (2013), 6 (2015), 7 (2017/2018) and 8 (2019) of the Survey of Health, Ageing and Retirement in Europe (SHARE) database. The analysis was conducted at both national and subnational levels, comprising 13 European countries. Health inequalities were assessed using the gini coefficient (GC) and concentration index (CI). Socioeconomic risk factors were included in the inequality analysis (urbanization, income, and educational level) in addition to multilevel regression model. The prevalence of DM decreased from 11% in wave 4 to 10.6% in wave 8, with the lowest recorded in Switzerland at 5.9% in wave 5 and the highest observed in Czechia at 16.7% in wave 8. DM prevalence varied widely subnationally, ranging from 2.1% in wave 8 Zentralschweiz (Switzerland) to 28.5% in wave 8 in Střední Čechy in Czechia. The GC demonstrated an increase from 21.9% (95% CI 17.0, 24.5) in wave 4 to 22.5% (95% CI 19.4,25.2) in wave 8, with Switzerland exhibiting the highest coefficient in wave 8 [30.1% (95% CI 7.9, 41.7)]. The CIs for income and educational level at national level were consistently low and mostly negative. The education and income CI ranged from [- 0.0182 (95% CI - 0.0242, - 0.0122) to - 0.0010 (95% CI - 0.0021, - 0.0001)] and [- 0.0278 (95% CI - 0.0411, -0.0166) to - 0.0018 (95% CI - 0.0032, - 0.0005)] across waves 4 and 8, respectively. The CI for urbanization displayed both negative and positive values, but most were not statistically significant (p > 0.05). Inequalities exist in the self-reported prevalence of DM both nationally and subnationally, with elevated rates observed among individuals with lower educational and income levels. Addressing these significant health inequalities calls for the development of prevention programs and policies by the European countries and subnational regions, specifically tailored to prioritize and support vulnerable groups.