Research in context
Evidence before this study
Lifetime risk estimates provide the cumulative risk of developing a disease during an individual's remaining lifespan. Previously, lifetime risk estimates have only been reported for overt type 2 diabetes on the basis of questionnaire data and not directly from a population with a long follow-up. Progression rates from prediabetes to diabetes have mostly been estimated for 10 years and not for the rest of an individual's remaining lifespan. So far, no previous study has included the direct calculation of the lifetime risks of developing the full range of impaired states of glucose metabolism by use of empirical data from a prospective population-based cohort study.
Added value of this study
Our findings showed that, in a well defined European population with long-term follow-up, half the normoglycaemic population eventually developed prediabetes, and most individuals with prediabetes eventually progress to overt type 2 diabetes. Furthermore, the lifetime risk to use insulin treatment for an individual aged 45 years not using insulin was 9%, suggesting that a high proportion of our population eventually uses insulin. Obesity substantially increased the lifetime risk of developing diabetes and attenuated the number of life-years lived with a healthy glucose metabolism. However, lean individuals also had a substantial lifetime risk of diabetes.
Implications of all the available evidence
The burden that impaired glucose metabolism exerts on the population is substantial and effective prevention strategies should be implemented as soon in a person's life as possible. The substantial lifetime risks of prediabetes and diabetes in lean individuals also support the implementation of risk factor control in non-obese individuals. Furthermore, the large proportion of individuals that will eventually use insulin treatments reflects the high health-care burden of type 2 diabetes.