By Dr M N Bhat

Mangaluru, Sep 26: Obesity, diabetes, and smoking are three of the most significant modifiable risk factors for heart attack and heart failure.

Smoking (or chewing Tobacco)

Chemicals in tobacco /smoke, like nicotine and carbon monoxide, damage the endothelium (the inner lining of arteries) of the coronary arteries that supply blood to the heart muscles. Damaged endothelium allows LDL ("bad") cholesterol to accumulate and form plaques. These plaques narrow the arteries, restricting blood flow to the heart. Smoking makes platelets in the blood more "sticky," significantly increasing the risk of blood clots forming. A clot can completely block a narrowed artery, leading to a heart attack or stroke. Carbon monoxide in smoke reduces the amount of oxygen delivered to the heart muscle, forcing the heart to work harder. Nicotine causes blood vessels to constrict (narrow), which increases blood pressure and reduces blood flow.

Diabetes patients have Hyperglycemia (High Blood Sugar): Chronically high blood sugar levels are toxic to the endothelium, causing widespread inflammation and damage to blood vessels throughout the body. Diabetes can lead to high levels of LDL cholesterol (bad cholesterol), high triglycerides, and low levels of HDL ("good") cholesterol. this causes cholesterol deposits in the coronary arteries.

Obesity is the primary driver of insulin resistance, which is the precursor to Type 2 diabetes. An obese body requires more blood to supply it with oxygen and nutrients. This forces the heart to pump harder, which is a risk factor for heart failure. Obesity is strongly linked to high cholesterol, sleep apnea, and hypertension.

These three factors interact and amplify each other's effects, creating a risk that is far greater than the sum of their individual effects.

This leads to Metabolic Syndrome—a constellation of conditions including abdominal obesity, high blood pressure, high blood sugar, and abnormal cholesterol levels.

The most important message is that these are modifiable risk factors:

• Quitting smoking has an almost immediate positive effect on cardiovascular risk.
• Weight loss achieved through diet and exercise can significantly improve blood pressure, cholesterol levels, and insulin sensitivity.
• Managing diabetes through diet, exercise, and medication is crucial for protecting the heart.

Dr M N Bhat is a consultant cardiology at KMC Hospital, Mangaluru.