Obesity and metabolic syndrome: Clinical sciences

Obesity is a condition characterized by excessive fat accumulation in the body, and is strongly associated with the development of other conditions, such as type 2 diabetes mellitus, dyslipidemia, cardiovascular disease, and even malignancy. Multiple factors contribute to the development of obesity, including genetics, western diet, sedentary lifestyle, inadequate sleep, and certain medication side effects.

Body fat, also known as adipose tissue, secretes adipokines, which can lead to widespread systemic inflammation and insulin resistance. Based on the body mass index, or BMI for short, individuals with obesity can be categorized into 4 main groups that include overweight, class I obesity, class II obesity, and class III obesity.

Now, if you suspect obesity, first you should obtain a focused history and physical. History may reveal symptoms like joint pain, snoring, fatigue, and dyspnea, as well as mood symptoms, such as depression. Additionally, the patient might present with obesity-related comorbidities, such as metabolic syndrome, diabetes mellitus, hypertension, and dyslipidemia. On the other hand, physical exam will reveal excess adipose tissue and larger waist circumference, and some patients may also have abdominal striae, acanthosis nigricans, and lower extremity edema.

Okay, the next step is to calculate the BMI using the patient’s weight in kilograms and height in meters. If the BMI is 25 to 29.9, the patient is overweight; if the BMI is between 30 and 34.9, the patient falls under class I obesity; between 35 and 39.9 is class II obesity; and finally, a BMI greater than or equal to 40 is class III obesity.

Here’s a clinical pearl for you! Though the diagnosis of obesity hinges on BMI, keep in mind that it's an imperfect individual measure. In fact, certain racial and ethnic groups, such as those with ancestry from some parts of Asia, may experience complications of obesity at lower BMIs, while others with higher BMIs but low adiposity have a lower risk of these complications.

Now, patients who are overweight or class I obesity get the same approach. In both groups, your next step is to assess for obesity-related comorbidities like hypertension, obstructive sleep apnea or OSA, non-alcoholic fatty liver disease or NAFLD, and dyslipidemia, as well as prediabetes and type 2 diabetes mellitus.

Now, here’s a high yield fact to keep in mind! It’s important to note that obesity is an independent risk factor for the development of cardiovascular diseases, such as coronary artery disease; but also conditions like hypertension, dyslipidemia, and diabetes mellitus, which further increase the risk. In other words, make sure to screen your patients regularly for these conditions and treat them appropriately to minimize the risk of cardiovascular events.

Many overweight and obese individuals will also have metabolic syndrome, which is diagnosed if there are three or more of the following criteria. The first one is a waist circumference of 40 inches or more in a biological male, or 35 inches or more in a biological female. The second one is a systolic blood pressure of 130 mmHg or more, and diastolic blood pressure of 85 mmHg or more. Keep in mind that this second criterion is also met if an individual is already on antihypertensive medications.

Next up is a triglyceride level of 150 mg/dL or more, or an individual already on medications to lower their triglycerides. The fourth criterion is HDL cholesterol less than 40 mg/dL in biologically male individuals, or less than 50 mg/dL in biologically female individuals, or a patient already on medication for low HDL. Finally, the fifth criterion is a fasting glucose equal to or greater than 100 mg/dL, a prior diagnosis of type 2 diabetes mellitus, or the use of antihyperglycemic medications.