Prevalence and socioeconomic predictors of diagnosed and undiagnosed diabetes in oldest-old and younger Caucasian seniors: results from the PolSenior study

Introduction: Type 2 diabetes is one of the most common diseases in the aging population; however, data concerning correlates of diabetes in age-advanced individuals are limited. The study aimed to identify the socioeconomic correlates of diabetes in representative groups of oldest-old (>= 85 years) and younger (65 to 84 years) Polish Caucasian seniors. Material and methods: PolSenior is a multicentre, population-based study conducted in Poland. Fasting plasma glucose levels and data from detailed medical questionnaires were obtained from 2128 male and 1961 female study participants aged >= 65 years. Multivariate logistic regression was used to identify significant socioeconomic risk factors for diabetes and undiagnosed diabetes. Results: The overall prevalence of diabetes in the study group was 21.9% (24.0% in women vs. 19.9% in men, p = 0.002), with an estimated weighted prevalence for all older Poles of 23.1%. Nearly one-fifth of cases were previously undiagnosed. Diabetes was more common in the younger elderly (65-84 years) than in the oldest-old (>= 85 years) (23.4% vs. 18.6%, p < 0.001). The frequency of diabetes was higher in women than in men (24.0% vs. 19.9%, p < 0.002); however, men remained undiagnosed more commonly than women (4.7% vs. 3.3%, p = 0.029). The frequency of diabetes was higher among urban than rural dwellers (23% vs. 20.4%, p = 0.048). It was also related to marital status in women (p = 0.036) and occupation in men (p = 0.015). Multivariate logistic regression analysis revealed that the independent risk factors for diabetes were body mass index (BMI) and marital status in women, while in men it was solely BMI. Undiagnosed diabetes was more frequent among rural than city dwellers (4.8% vs. 3.5%, p = 0.03). In multivariate logistic regression analysis, only BMI and place of residence remained significant risk factors for being undiagnosed. Conclusions: The prevalence of diabetes in the >= 65-year-old population exceeds 20% but is lower in the oldest- old than in the younger elderly and is modified by socioeconomic factors. Many elderly individuals remain undiagnosed and do not benefit from the currently available therapy.