In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the body through the lymphatic system or bloodstream; this is called metastasis. Cancers are primarily associated with environmental factors such as smoking or excessive alcohol consumption. Some cancers have a very strong genetic risk associated with their development. Oncogenes are genes that promote cell growth and reproduction. Tumor suppressor genes inhibit cell division and survival. Malignant transformation can occur through the formation of novel oncogenes, the inappropriate over-expression of normal oncogenes, or by the under-expression or disabling of tumor suppressor genes. Cancer treatment options include surgery, chemotherapy, and radiation. Alternative treatments are being explored through clinical trials.
The term "heart disease" is often used interchangeably with the term "cardiovascular disease." Cardiovascular disease generally refers to conditions that involve narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke. Other heart conditions, such as those that affect your heart's muscle, valves or rhythm, also are considered forms of heart disease.
Overweight and obesity together make up one of the leading preventable causes of death in the U.S. Obesity is a chronic disease that can seriously affect your health. Overweight means that you have extra body weight, and obesity means having a high amount of extra body fat. Being overweight or obese raises your risk for health problems. These include coronary heart disease, type 2 diabetes, asthma, high cholesterol, osteoarthritis, high blood pressure, sleep apnea, and certain types of cancer. Public health experts agree that overweight and obesity have reached epidemic proportions in this country and around the world. More than a third of U.S. adults are obese. People ages 60 and older are more likely to be obese than younger adults, according to the most recent data from the National Health and Nutrition Examination Survey. And the problem also affects children. Approximately 20%, of U.S. children and adolescents ages 2 to 19 are obese.
Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin. Insulin is a hormone needed to allow sugar (glucose) to enter cells to produce energy. Different factors, including genetics and some viruses, may contribute to type 1 diabetes. Although type 1 diabetes usually appears during childhood or adolescence, it can develop in adults. Despite active research, type 1 diabetes has no cure. Treatment focuses on managing blood sugar levels with insulin, diet and lifestyle to prevent complications.