Knowledge of risk of developing diabetes mellitus among siblings of Type 2 diabetic patients

Aims: We set out to investigate the extent to which siblings of diabetic subjects perceived themselves likely to develop Type 2 diabetes mellitus (DM) when offered screening tests. Methods: Nondiabetic siblings, aged 35-74 years, of Type 2 diabetic patients who were more than 35 years old at diagnosis had fasting plasma glucose measured in a study to determine heritability of diabetes. Questionnaires assessing perceived likelihood of developing, seriousness and knowledge about diabetes were completed. Logistic regression assessed factors predicting perceptions of diabetes risk. Results Factors predicting diabetes on screening were male sex, increasing age and body mass index (BMI)≥30. Eighty-nine per cent of 540 eligible siblings completed questionnaires. Thirty-eight per cent saw themselves at increased risk of diabetes and 34% thought diabetes a serious problem. Predictors of perceiving an increased likelihood of developing diabetes were female sex, age 35-54 years vs. 55-74 years and having a parent with diabetes. BMI did not affect perceptions of likelihood. Conclusion: A perception of reduced vulnerability to diabetes may occur due to unawareness of risk or minimization of risk. Feelings of invulnerability may affect emotional response to a subsequent result. It is not known whether providing more information about the risk of developing diabetes prior to screening would affect outcomes.