Obesity and Comorbid Conditions

Excerpt

Obesity, as defined by the World Health Organization (WHO), is characterized by the abnormal or excessive accumulation of fat that poses a health risk. This condition has been recognized since ancient times, with Hippocrates noting that obesity is not merely a disease but also a precursor to other health conditions. The most widely used measurement of obesity is the body mass index (BMI), which was introduced in 1972 and has undergone minimal changes since then. However, other methods, such as waist-to-hip ratios, skin impedance, and dual x-ray absorptiometry, are also utilized.

The BMI numbers and classifications are listed below. However, individual variations exist, and BMI alone is insufficient to classify a person as obese or malnourished. BMI has limitations, particularly in specific populations such as elite athletes and bodybuilders, where increased muscle mass can falsely elevate BMI and not accurately reflect health status. In the pediatric population, BMI allows for comparison between children of the same sex and age. A BMI below the 5th percentile is considered underweight for children, while a BMI above the 95th percentile is considered obese. Please see StatPearls' companion resource, "BMI Classification Percentile And Cut Off Points," for further information.

Numbers and Classifications of Body Mass Index

1. Severely underweight individuals: BMI <16.5 kg/m²

2. Underweight individuals: BMI <18.5 kg/m²

3. Individuals with normal weight: BMI ≥18.5 to 24.9 kg/m²

4. Individuals who are overweight: BMI ≥25 to 29.9 kg/m²

5. Obesity: BMI ≥30 kg/m²

   1. Obesity class I: BMI 30 to 34.9 kg/m²

   2. Obesity class II: BMI 35 to 39.9 kg/m²

   3. Obesity class III: BMI ≥40 kg/m² (also referred to as severe, extreme, or massive obesity)

6. Asian and South Asian populations

   1. Individuals who are overweight: BMI between 23 and 24.9 kg/m²

   2. Obesity: BMI >25 kg/m²

Notably, different countries and ethnicities have different cutoffs for obesity, especially in Asia. For instance, Japan uses a BMI greater than 25 kg/m² as the cutoff for obesity.

Obesity significantly impacts an individual's physical, mental, and social health. In addition, increased body weight has adverse effects on society through higher healthcare expenditures. Global obesity rates have seen a dramatic increase in the last decade, often described as a pandemic. The Centers for Disease Control and Prevention (CDC) reports that 42.4% of all adults in the United States experience obesity, and worldwide, obesity affects 650 million people. An urgent need exists for increased emphasis on health promotion and patient education to facilitate weight loss and prevent complications.