Non-communicable diseases (NCDs) are chronic conditions that are not passed from person to person, such as cardiovascular issues, cancers, chronic respiratory diseases, and diabetes. These conditions develop over long periods and are the leading cause of death and disability worldwide, with a majority of these deaths occurring in low- and middle-income countries.
Behavioral Risk Factors
Lifestyle habits are significant contributors to NCD risk. Tobacco use, through smoking, chewing, or second-hand smoke exposure, is a primary example. Its chemicals can damage blood vessels, leading to cardiovascular diseases, and contain carcinogens that increase the risk for cancers of the lung, mouth, and throat.
Dietary choices also play a substantial role. Diets high in sodium are linked to higher blood pressure, while those rich in sugars and unhealthy fats contribute to weight gain. Conversely, a diet lacking in fruits and vegetables deprives the body of protective fiber and micronutrients.
The harmful use of alcohol is another behavioral factor. Excessive consumption can lead to liver damage, including cirrhosis and an increased risk of liver cancer. It also contributes to high blood pressure, can weaken the heart muscle, and is linked to a higher incidence of cancers of the esophagus, colon, and breast.
A lack of physical activity compounds other risks. Sedentary lifestyles contribute directly to weight gain and can impair the body’s ability to regulate blood sugar and blood pressure. Regular physical activity helps maintain a healthy weight and improves cardiovascular function, thereby reducing the risk for several major NCDs.
Metabolic Risk Factors
Metabolic risk factors are measurable biological changes, often arising from behavior, that elevate the risk for NCDs. One of the most common is raised blood pressure (hypertension). This condition forces the heart to work harder, which can strain and damage arteries over time, leading to heart attacks, strokes, and kidney failure.
Overweight and obesity, an excess accumulation of body fat, also present a risk. This excess fat is an active metabolic tissue that can release inflammatory substances. These substances contribute to insulin resistance and chronic inflammation, setting the stage for type 2 diabetes, cardiovascular diseases, and certain cancers.
High blood glucose (hyperglycemia) is another metabolic indicator. It occurs when the body cannot produce or effectively use insulin, leading to elevated sugar levels in the blood. Persistent hyperglycemia is the defining characteristic of diabetes and can damage nerves, blood vessels, and organs over time.
High levels of lipids like cholesterol in the blood is known as hyperlipidemia. Excessive amounts of low-density lipoprotein (LDL) cholesterol can lead to plaque formation in the arteries, a process called atherosclerosis. These plaques can narrow or block blood vessels, directly causing heart attacks and strokes.
Genetic and Biological Risk Factors
Some risk factors are an inherent part of an individual’s biology and cannot be changed. The primary non-modifiable risk factor for most NCDs is advancing age. As the body gets older, cellular repair mechanisms become less efficient, and the cumulative effects of other risk factors accumulate, leading to a higher incidence of conditions like heart disease and cancer.
Biological sex can also influence the risk profile for certain NCDs. For instance, men tend to have a higher risk of heart disease at a younger age compared to pre-menopausal women, while some autoimmune conditions are more prevalent in women. These differences are attributed to a combination of hormonal factors, genetics, and behavioral patterns.
An individual’s genetic makeup can create a predisposition for certain NCDs. A family history of conditions like early-onset heart disease or specific cancers may indicate inherited genetic variants that increase susceptibility. These genes can influence how the body processes cholesterol or repairs DNA damage, but this inheritance does not guarantee disease.
Environmental and Socioeconomic Determinants
A person’s environment can present significant risks for NCDs. Air pollution from indoor sources like cooking fires or outdoor sources like traffic is a major contributor. Inhaling fine particulate matter can trigger inflammation in the lungs and cardiovascular system, increasing the risk of chronic respiratory diseases, heart attacks, and strokes.
Socioeconomic status, including income and education level, is a strong determinant of health outcomes. Individuals with lower incomes often face greater exposure to NCD risks, such as living in areas with higher pollution. They may also have limited resources to afford healthier foods or access preventative healthcare.
Access to healthcare and healthy living options is not distributed equally. People in “food deserts,” areas without nearby supermarkets, may rely on processed foods, while a lack of safe parks can discourage physical activity. Limited access to medical services can mean that conditions like high blood pressure go undetected and untreated, allowing them to progress.