A risk factor is best defined as which of the following?

• A. A single gene
• B. Any situation, habit, social or environmental condition, physiological or psychological condition, developmental or intellectual condition, or spiritual or other variable that increases vulnerability to illness or accident
• C. Only dangerous environments
• D. A personal habit only

Answer: (B)

Risk factors are variables that increase a person’s likelihood of developing disease or experiencing injury. They can be genetic, behavioral, environmental, physiological, psychological, developmental, intellectual, spiritual, or social—any condition or characteristic that raises vulnerability. This broad view explains why health outcomes often result from multiple influences across different domains, and why risk can come from more than one factor at a time. For example, genetic predisposition is one type of risk factor, but so are lifestyle habits like smoking, environmental exposures, stress, or low access to care. The definition that includes any situation, habit, or condition across these domains best captures how risk factors operate. The other options are too narrow, focusing only on a single gene, only dangerous environments, or only personal habits.