What is the primary cause of diabetes in India?

Primary Causes of Diabetes in India

The primary cause of diabetes in India is the combination of genetic predisposition coupled with rapid urbanization and socioeconomic development leading to lifestyle changes, including increased obesity, physical inactivity, and unhealthy dietary patterns over the past three decades. 1, 2

Genetic Factors

• Indians have a unique "Asian Indian Phenotype" characterized by increased insulin resistance, greater abdominal adiposity despite lower body mass index, lower adiponectin, and higher C-reactive protein levels, making them more susceptible to diabetes 3
• Genetic predisposition is a significant factor, with family history of diabetes strongly associated with type 2 diabetes (frequency of type 2 diabetes in first or second-degree relatives ranges from 74-100%) 4
• The genetics of type 2 diabetes in Indians are complex and not fully defined, but contribute significantly to the high prevalence 4

Lifestyle and Environmental Factors

• Rapid urbanization has led to decreased physical activity due to improved transportation and less physically demanding occupations 5
• Westernized lifestyle adoption, including decreased exercise and increased calorie and fat intake, is strongly associated with increased frequency of type 2 diabetes 4
• Obesity is a very common finding in patients with type 2 diabetes, with most patients having BMI greater than the 85th percentile for age and sex 4
• Environmental factors contribute to type 2 diabetes development by altering epigenetic processes such as DNA methylation and histone modifications 1

Epidemiological Transition

• India ranks second globally in diabetes cases, with approximately 77 million individuals having diabetes in 2019, expected to rise to over 134 million by 2045 2
• About 57% of diabetes cases in India remain undiagnosed, complicating prevention and management efforts 2
• The most concerning trend is the shift in age of onset to younger populations in recent years, which has long-lasting adverse effects on the nation's health and economy 3

Pathophysiology

• Type 2 diabetes, which accounts for 90-95% of all diabetes cases, involves relative insulin deficiency and peripheral insulin resistance 4
• The initial abnormality is typically impaired insulin action, later compounded by β-cell failure 4
• Insulin resistance may improve with weight reduction, physical activity, and/or pharmacological treatment but is seldom restored to normal 4
• The failure of β-cells to continue hypersecreting insulin underlies the transition from insulin resistance with compensatory hyperinsulinemia to clinical diabetes 4

Risk Factors Specific to India

• Low thresholds for risk factors such as age, body mass index, and upper body adiposity enhance conversion to diabetes 5
• Prediabetic conditions like impaired glucose tolerance and impaired fasting glucose are rising, indicating potential for further increases in diabetes prevalence 5
• Metabolic syndrome, a constellation of cardiovascular risk factors including hyperglycemia and insulin resistance, is widely prevalent 5
• The combination of genetic phenotype (low BMI but high upper body adiposity and body fat percentage) with environmental changes creates a perfect storm for diabetes development 5

Prevention Strategies

• Early identification of high-risk individuals using simple screening tools like the Indian Diabetes Risk Score (IDRS) can help prevent or postpone diabetes onset 3
• Lifestyle interventions including maintaining healthy body weight, consuming a healthy diet, staying physically active, not smoking, and moderate alcohol consumption could prevent many cases 6
• Aggressive interventions and vigilant follow-up should be pursued for those at very high risk (e.g., those with A1C >6.0% and individuals with both impaired fasting glucose and impaired glucose tolerance) 4

Common Pitfalls in Diagnosis and Management

• Type 2 diabetes may go undiagnosed for many years because hyperglycemia develops gradually and may not be severe enough to cause noticeable symptoms 4
• The catabolic syndrome in diabetes may be missed in early stages when hyperglycemia develops gradually 7
• Increased extracellular fluid may mask actual loss of body cell mass and fat in diabetic patients 7
• Patients with diabetes and catabolic illness have increased protein requirements that must be addressed to prevent further muscle wasting 7