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Diabetes mellitus is a significant public health problem, increasing worldwide, and is commonly associated with overweight or obesity. However, a relatively lesser-known type of diabetes, known as lean diabetes (individuals with a low body mass index BMI), poses a significant threat in low- and middle-income countries (LMICs), particularly amongst the poor and impoverished population.1 Tripathy and Kar introduced the term 'lean' diabetes to describe this specific form of diabetes as 'dual stress of intermittent starvation and overload on carbohydrate metabolism may be related to the atypical patterns of clinical diabetes'.2 In 1985, the World Health Organization acknowledged 'malnutrition-related diabetes mellitus' amongst individuals with a low BMI (<19 kg/m2). However, this classification was withdrawn in 1999 due to insufficient supporting evidence. Nonetheless, subsequent research has indicated that malnutrition-related diabetes is not uncommon in low- and middle-income countries, suggesting the need for its recognition as a distinct form of diabetes.3 In population-based studies, the proportion of type 2 diabetes varied between 1.4% and 10.9%. Nevertheless, when considering individuals with a BMI <25 kg/m2, the occurrence of type 2 diabetes ranged from 1.4% to 8.8%. In Asian and African countries, a significant proportion of individuals with diabetes, ranging from 24% to 66%, were underweight or had a normal weight, which is notably higher than the proportion of 10% observed in the United States.4 Individuals with lean diabetes were more likely to be older, illiterate and engaged as manual labourers compared to those with non-lean diabetes.5 There has been a rise in the incidence of diabetes and other chronic non-communicable diseases amongst the indigenous community in recent years. These communities primarily rely on traditional and local healing practices, but modernisation has led to rapid changes in their lifestyle, food habits and occupation.6 Research suggests that malnutrition or protein deficiency and poor socio-economic status are linked to the development of lean diabetes, which affects individuals who are not overweight or obese.1 Researchers have found that lean people who had prenatal or early childhood malnutrition, insulin resistance or epigenetic alterations were more likely to acquire type 2 diabetes later in life.1,5,7 There is mounting evidence that diabetes is mostly attributable to an overreliance on rice and a decline in physical activity caused by a change in lifestyle amongst India's poorest tribal groups.8 Amongst genetic factors, a variant in the LAMA1 gene may contribute to the development of lean diabetes amongst non-obese individuals, irrespective of lifestyle and obesity-related factors.9 Studies also indicate that poor pancreatic development and hepatic fat deposition can reduce metabolic capacity, increasing the risk of diabetes amongst this population group.10,11 The illness often presents itself in early adulthood, is more common in males, and is associated with increased rates of cigarette smoking and drinking.1,7 Despite elevated blood glucose levels (fasting plasma glucose exceeding 200 mg/dL), such individuals do not exhibit ketonuria or ketosis.12 They have substantial insulin requirements, exceeding 60 IU/day or 2.0 units/kg/day.13 A recent study conducted in Vellore (CMC), India, showed that insulin secretion and glucose production were lower in lean individuals with diabetes with diminished beta-cell function.3 Individuals with lean diabetes are at increased risk of developing cardiovascular disease, nerve damage, kidney disease, foot disease and blindness.1,7,8 It is also associated with hyperglycaemia, a critical condition that requires urgent medical attention.14 Individuals with lean diabetes have higher levels of glycated haemoglobin, fasting and post-prandial blood glucose and a higher prevalence of microvascular complications such as retinopathy, nephropathy and neuropathy.7,15 Lean patients with diabetes might experience higher rates of both cardiovascular and non-cardiovascular mortality in comparison to obese individuals with diabetes.1 Healthcare facilities in indigenous territories are often understaffed and underfunded, making them inefficient and inadequate. The involvement of tribal communities in the planning, provision and oversight of healthcare is largely absent. The healthcare needs of tribal populations are often overlooked because of a paucity of data specific to tribal health and the absence of a dedicated administrative framework to plan, deliver and monitor healthcare in tribal areas.16,17 In addition, tribal communities have a lack of compliance with treatment and the absence of guidelines to control diabetes makes it more challenging.8 Given the lack of healthcare staff, geographical isolation, insufficient information, lack of awareness and social stigma around healthcare, the screening for diabetes amongst the tribal population is low and the follow-up ratio remains poor, which further worsens their condition.18 Addressing lean diabetes amongst underserved populations requires a multifaceted approach Figure 1. An accurate assessment and knowledge of the disease burden are vital for evaluating the public health significance of this atypical type of diabetes. Increased access to healthcare is a vital aspect of the prevention and management of diabetes. Universal screening at primary health centres and sub-centres could be done as a necessary step to detect diabetes cases in tribal areas since early detection is important for treating diabetes individuals. Thus, strengthening the public healthcare system is indispensable to providing adequate health services for the treatment and control of diabetes amongst tribal populations.19 Since tribal populations are less likely to diagnose non-communicable diseases, including diabetes, local stakeholders and community health workers need to engage and encourage them to access healthcare services. Empowering tribal communities by equipping them with accurate information about the disease is also essential.16 The involvement of traditional healers and Dais is significant in indigenous healthcare amongst the tribal population. Rather than isolating or disregarding the traditional healers, it is crucial to seek their cooperation for an integrative healthcare.20 In addition, it is crucial to implement policies and activities that effectively tackle the root causes of the disease, such as poverty and malnutrition. The growing prevalence of the disease in LMICs underscores the need for increased awareness and investment in prevention and management. It is essential to prioritise lean diabetes as a public health issue and implements comprehensive measures to prevent, detect and manage the disease effectively.Figure 1: Causes and risk factors of lean diabetes: Approaches to improve health in the underserved community. BMI: Body mass index, CVD: Cardiovascular diseaseFinancial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Kotha et al. (Mon,) studied this question.