Estimating life expectancy based on the age of type 2 diabetes diagnosis

By Dr. Priyom Bose, Ph.D.Reviewed by Lily Ramsey, LLMSep 13 2023

A recent Diabetes and Endocrinology study estimated the association between the age of diabetes diagnosis and life expectancy.

Study: Life expectancy associated with different ages at diagnosis of type 2 diabetes in high-income countries: 23 million person-years of observation. Image Credit: ProximaStudio/Shutterstock.com

Background

In 2021, around 537 million adults worldwide were diagnosed with diabetes. In recent years, the number of younger individuals diagnosed with diabetes has increased substantially.

The increased global prevalence of type 2 diabetes has been associated with behavioral and societal factors linked to physical activity, obesity, and nutrition. 

Previous studies have estimated that adults with type 2 diabetes die approximately six years earlier than their counterparts without diabetes.

Previous modeling studies have assessed the effect of diabetes on life expectancy, considering the prevalence of diabetes as a binary condition, i.e., present or absent. However, no studies have investigated whether the reduction in life expectancy changes based on the age of diagnosis. 

About the study

The current study analyzed how age at diagnosis of diabetes affects cause-specific mortality, all-cause mortality, and disease in life expectancy in high-income countries.

Two large-scale data sources, namely, the Emerging Risk Factors Collaboration (ERFC) and the UK Biobank, were used in this study.

ERFC contains data from prospective cohort studies about various risk factors, cardiovascular disease outcomes, and mortality. UK Biobank contains a dataset of a large prospective study, which includes participants from 22 centers throughout the UK.

This study included only diabetic participants whose age at diagnosis of diabetes was noted. All participants in the UK Biobank have been linked with death records of the UK Office through National Health Service identification numbers.

Study findings

The current study analyzed population-based longitudinal data from nineteen high-income countries. A robust linear dose–response relationship was observed between earlier age at diabetes diagnosis and a higher risk of all-cause mortality.

The modeling approach used in this study indicated that every decade of earlier diabetes diagnosis was associated with approximately three to four years of reduced life expectancy.

This study indicated that individuals diagnosed with diabetes at the age of 30 years died fourteen years earlier than those without diabetes at a similar age.

Similarly, individuals who were diagnosed with diabetes at the age of 40 years died ten years earlier, and those diagnosed at the age of 50 died six years earlier than their healthy counterparts.

A robust association was established between earlier age of diabetes diagnosis and deaths due to vascular and non-neoplastic conditions. Common vascular diseases include stroke and myocardial infarction, while non-neoplastic conditions include neurological, respiratory, and infectious diseases.

The association between life expectancy and diabetes was marginally greater in women than in men. Compared to older adults, higher hazard ratios for mortality were associated with earlier age of diabetes detection. 

The effect of diabetes is greatest in the population at the lowest risk of underlying conditions.

A previous study suggested that individuals who developed type 2 diabetes at a younger age are more prone to experience aggressive conditions, such as higher blood pressure, obesity, faster deterioration in glycaemic control, and higher concentrations of proatherogenic lipids. These conditions could lead to premature mortality.

Conclusions

The study design is the key strength of this study, which focusses on the age when diabetes was first diagnosed. This age was determined using information from people diagnosed with prevalent diabetes and those diagnosed with incident diabetes.

Another strength of this study is the estimation of reduction in life expectancy based on age-specific HRs determined through individual-level data. This approach is favorable since HRs are less variable across similar populations.

The current study has some limitations. For instance, it included studies that defined diabetes differently; however, no significant differences in result outcomes were observed.

A pathophysiological subtype of diabetes was not considered due to lack of data. In addition, no data suggested variable treatment based on the age of diabetic patients or their follow-up conditions.

However, these data would have helped in assessing long-term disease outcomes. Most participants in this study were linked to European continental ancestry, which limited the generalizability of the findings.

Despite the limitations, this study revealed that every decade of earlier diagnosis of diabetes is associated with reductions in life expectancy.

Considering the findings of this study, there is an urgent need to develop and implement effective interventions to prevent or delay the onset of diabetes, particularly for the younger adult age group.