"Individual behavior also plays a role in health outcomes. For example, if an individual quits smoking, his or her risk of developing heart disease is greatly reduced. Many public health and health care interventions focus on changing individual behaviors such as substance abuse, diet, and physical activity. Positive changes in individual behavior can reduce the rates of chronic disease in this country. Examples of individual behavior determinants of health include diet, physical activity, alcohol, cigarette, and other drug use, and hand washing. Some biological and genetic factors affect specific populations more than others. For example, older adults are biologically prone to being in poorer health than adolescents due to the physical and cognitive effects of aging. Sickle cell disease is a common example of a genetic determinant of health. Sickle cell is a condition that people inherit when both parents carry the gene for sickle cell. The gene is most common in people with ancestors from West African countries, Mediterranean countries, South or Central American countries, Caribbean islands, India, and Saudi Arabia. Examples of biological and genetic determinants of health include age, sex, HIV status, inherited conditions such as sickle-cell anemia, hemophilia, and cystic fibrosis, carrying the BRCA1 or BRCA2 gene, which increases risk for breast and ovarian cancer, and family history of heart disease."