New Delhi: Lean diabetes may be one end of the spectrum of type 2 diabetes but is characterised by an earlier age of onset, more severe insulin deficiency and increased risk of microvascular complications, the largest analysis of this diabetes subtype from India has shown.
This specific diabetes is named so for affecting individuals with a body mass index (BMI) of less than 18.5 and particularly prevalent in the South Asian populations.
But unlike classical type 2 diabetes or diabetes mellitus, which is commonly associated with obesity and insulin resistance, lean diabetes often presents with more severe beta-cell (cells in pancreas that play a role in releasing insulin) dysfunction and relatively less insulin resistance.
This has been reported in a new scientific paper published in the Journal of Diabetes and its Complications in July by scientists associated with the Madras Diabetes Research Foundation (MDRF).
Overall, diabetes poses a significant public health challenge in India, with the latest estimates suggesting that there are 101 million people with this condition.
Over 90 percent of individuals diagnosed with diabetes have type 2 diabetes, a disorder that is commonly associated with obesity and insulin resistance, where the body’s cells don’t respond normally to insulin, making it harder for glucose to enter and be used for energy.
The current classification systems for diabetes, including the traditional type 1 diabetes- when diabetes occurs due to autoimmune reasons and type 2 diabetes, as well as more recent cluster-based approaches, have significantly advanced the understanding of disease heterogeneity in diabetes.
Yet, frameworks often fall short in recognising atypical presentations such as individuals with lean diabetes, who may exhibit significant beta-cell dysfunction without the classical features of insulin resistance or autoimmunity, making them difficult to categorise within existing models, the researchers noted.
They also highlighted that this phenotype is particularly prevalent in South Asian populations and poses unique diagnostic and therapeutic challenges.
Evolving understanding
Lean diabetes is most often seen in people in their 40s and 50s who look lean. In India, doctors estimate that about 3 to 5 percent of the population may have it.
What makes this form concerning is that it is not just about lifestyle choices but childhood undernutrition, poor access to balanced diets, and even genetic factors appear to play a role.
In fact, people from lower socioeconomic backgrounds are often more vulnerable, and sometimes whole families can be affected despite healthy habits, pointed out Dr Abhijit Bhograj, consultant—endocrinology, diabetes and thyroid with Manipal Hospital in Bengaluru.
Lean diabetes is often missed or mistaken for type 2 diabetes, and that is where the real problem lies, say experts, underlining that people with lean diabetes face a higher risk of serious complications such as kidney disease, nerve damage, and heart problems.
This is why it is crucial to identify lean diabetes as a distinct condition, clinicians and scientists maintain.
“Greater awareness enables doctors to diagnose and treat patients correctly. To know that diabetes is not always linked with obesity is helpful to the general public and this promotes individuals to have regular health checks and reduces stigma,” Dr Bhograj said.
Though first identified over 2 decades back, most earlier studies on lean diabetes have been limited by small sample sizes and there has been little data available on microvascular complications in this specific subtype of diabetes.
Given the growing recognition of lean diabetes as a clinically distinct entity, there remains a significant gap in understanding its metabolic and complication profile, the researchers noted.
Medical records of 6,32,830 individuals seen at MDRF between 1992 and 2023 across eight states were analysed to provide deeper phenotypic data, including data on pancreatic beta cell function and microvascular complications in lean diabetes, compared to other categories of adiposity (the degree of fattiness) among diabetes to see whether this group, stands out as a separate entity or is a continuum of diabetes.
They showed that the mean age of lean diabetes patients whose records were analysed stood at 45.2 years, lower than other diabetes patients.
While the etiology (cause) of lean diabetes is far from clear, genetic factors, combined with environmental influences may play a role in its development, the researchers noted, stressing that individuals with lean diabetes can show considerably better health outcomes with early identification and tailored management.
Treatment may differ from typical diabetes treatment by emphasising lifestyle interventions focused on improving insulin sensitivity and addressing potential underlying metabolic defects, rather than solely focusing on weight loss, said an Indian Council of Medical Research (ICMR) researcher who works on non-communicable diseases.
(Edited by Tony Rai)
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