Type 2 diabetes has typically been a condition affecting middle-aged or older adults. In recent years, however, there has been an increase in younger people presenting with type 2 diabetes. Early-onset type 2 diabetes is associated with a faster progression to microvascular1 and macrovascular2 complications than later-onset type 2 diabetes, and has a significantly reduced life expectancy.3
EPIDEMIOLOGY
‘In the last five years, there has been an increase of about 18% in the cross-sectional prevalence of type 2 diabetes in those aged under 40 years…’
The term early-onset type 2 diabetes is defined as a diagnosis at under 40 years of age. It includes children and adolescents, though younger adults, aged 18–39 years, account for most cases.4
The English National Diabetes Audit (NDA) has found approximately 150,000 people currently living with early-onset type 2 diabetes in England. In the last five years, there has been an increase of about 18% in the cross-sectional prevalence of type 2 diabetes in those aged under 40 years, compared with an 11% increase in older age groups. Although the incidence of early-onset type 2 diabetes is still comparatively low compared with typical, older-onset type 2 diabetes, this rapid increase (observed both in the UK and globally) is concerning.4
The risk factors are similar to later-onset type 2 diabetes, but appear to be amplified. Certain populations are at particular risk, including those living with obesity at young age and people from ethnic groups including South Asian, East Asian, African–Caribbean, Middle Eastern and First Nation populations. In the UK, the rising prevalence is predominantly driven by an increase in young adults of White British ethnicity, and South Asian and African–Caribbean ethnicities are also disproportionately affected.5 There appears to be a female preponderance at younger ages, but this balances out as the age of onset approaches 40 years. There is a strong association with socioeconomic deprivation.
The adverse outcomes associated with early-onset type 2 diabetes are stark. In an analysis across 19 high-income countries, life expectancy was significantly reduced, with a diagnosis at the age of 30 years leading to around 15 years’ loss of life expectancy.3 Women with early-onset type 2 diabetes also experience adverse pregnancy outcomes, including higher rates of perinatal death compared with pregnancies in women with type 1 diabetes.6
WHAT UNDERLIES THE ADVERSE OUTCOMES?
The higher burden of complications could simply be a result of a longer duration of diabetes. Better studies are needed to investigate this. However, a meta-analysis showed that, when adjusted for current age (or duration), each one-year decrease in age at diagnosis was associated with a 3% increase in macrovascular disease and a 5% increase in microvascular disease.7
‘Importantly, there may also be individual patient factors, such as socioeconomic deprivation, that affect engagement with self-management and, in turn, impact risk of adverse outcomes.’
Another explanation might be exposure to multiple cardiometabolic risk factors from young age. Studies have shown that younger individuals with type 2 diabetes have a higher body mass index (BMI), a more adverse lipid profile and a higher glycated haemoglobin (HbA1c) at diagnosis, compared with patients with later-onset type 2 diabetes.8
The trajectory of early-onset type 2 diabetes also appears to be different, with several studies demonstrating a rapid worsening of β-cell function and a rapid progression to insulin treatment.9 Importantly, there may also be individual patient factors, such as socioeconomic deprivation, that affect engagement with self-management and, in turn, impact risk of adverse outcomes.
RECOGNISING THE NEED FOR TARGETED CARE
The NDA has shown that people with early-onset type 2 diabetes are least likely to receive diabetes care processes – the nine diabetes checks that all people with diabetes should receive annually. In the National Pregnancy in Diabetes Audit, two-thirds of women with pre-existing type 2 diabetes did not have HbA1c <48mmol/mol at conception, and only 5% received folic acid.5,6 We need to deliver better care, but what does good care look like?10
Classification
It is important to consider alternative diagnoses, including type 1 diabetes and monogenic diabetes. Some have argued that type 2 diabetes should be a diagnosis of exclusion in younger age groups. Some ethnic groups, for instance South Asian and East Asian, may not be significantly overweight when they present with early-onset type 2 diabetes. A leaner BMI in any young person labelled with type 2 diabetes should prompt diabetes classification tests.
HbA1c target
Once diagnosis is established, the HbA1c level should be reduced to tight targets. Guidelines recommend dual treatment with metformin and SGLT-2 inhibitors from diagnosis in high-risk groups.
Weight management
Currently, glucagon-like peptide-1 (GLP-1) agonist therapy remains fourth-line in NICE guidelines, but clearly a focus on sustainable weight reduction is necessary in addition to targeting glycaemia. Options include weight management programmes, GLP-1 agonist treatment, very low-calorie diets via the NHS Path to Remission Programme, and bariatric surgery for those eligible.
Cardiovascular risk reduction
There is a need to proactively screen for and treat hypertension and dyslipidaemia, recognising that cardiovascular risk engines underestimate life-time cardiovascular risk in those under 40 years of age.
Pregnancy
Women of child-bearing age should be encouraged to start contraception if they are not planning a pregnancy, so that medications can be used safely. For those planning pregnancy, preconception counselling is imperative.
SUMMARY
Early-onset type 2 diabetes presents a growing public health challenge, with a more aggressive disease trajectory and significantly worse outcomes when compared with later-onset cases.
Addressing this requires a multifaceted approach, including early and accurate diagnosis, tighter glycaemic control, structured weight management, and proactive cardiovascular risk reduction. Additionally, improving access to essential diabetes care processes and targeted preconception counselling for women is crucial. Prevention must also be a priority, with stronger efforts to reduce obesity and metabolic dysfunction in young people, if we are to reduce the rising incidence of early-onset type 2 diabetes.
SHIVANI MISRA
Senior Clinical Lecturer and Wellcome Trust Fellow, Department of Metabolism, Digestion and Reproduction, Imperial College London
REFERENCES
1. TODAY Study Group 2021 New England Journal of Medicine https://doi.org/10.1056/NEJMoa2100165.
2. Sattar N et al. 2019 Circulation https://doi.org/10.1161/circulationaha.118.037885.
3. Emerging Risk Factors Collaboration Group 2023 Lancet Diabetes & Endocrinology https://doi.org/10.1016/S2213-8587(23)00223-1.
4. Misra S et al. 2023 Lancet Diabetes & Endocrinology https://doi.org/10.1016/S2213-8587(23)00225-5.
5. Misra S et al. 2023 Diabetic Medicine https://doi.org/10.1111/dme.14940.
6. Murphy HR et al. 2021 Lancet Diabetes & Endocrinology https://doi.org/10.1016/s2213-8587(20)30406-x.
7. Nanayakkara N et al. 2020 Diabetologia https://doi.org/10.1007/s00125-020-05319-w.
8. Steinarsson AO et al. 2018 Diabetologia https://doi.org/10.1007/s00125-017-4532-8.
9. TODAY Study Group 2013 Diabetes Care https://doi.org/10.2337/dc12-2393.
10. Misra S et al. 2022 Diabetic Medicine https://doi.org/10.1111/dme.14927.
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