A Risk Factor Can Be Defined as Anything That Increases the Likelihood of Injury or Disease. True or False?
True. A risk factor is any characteristic, behavior, condition, or exposure that increases the likelihood (probability) that a person will develop an injury, illness, or disease. It raises risk but does not guarantee the outcome will occur.
The answer
True. A risk factor is defined as anything — a behavior, condition, exposure, characteristic, or circumstance — that increases the likelihood (probability) that a person will experience an injury, illness, or disease. Smoking increases the likelihood of lung cancer, high blood pressure increases the likelihood of heart disease, and not wearing a seatbelt increases the likelihood of injury in a crash. In every case the factor raises the odds; it does not decide the outcome on its own.
The key word in the definition is likelihood. A risk factor shifts probability, so having one means you are more likely than average to develop the condition — not that you certainly will, and not that someone without the factor is guaranteed to stay healthy.
Why this is true and not false
The statement matches the standard public-health definition exactly, so "false" would be incorrect. The only reason a student might hesitate is confusing a risk factor with a cause. That distinction is important:
- A cause directly produces the outcome (a virus causes a specific infection).
- A risk factor only raises the probability and may act alongside many others.
Because the statement says a risk factor "increases the likelihood" — not "causes" or "guarantees" — it is accurate. If the sentence had read "a risk factor always leads to disease," that would be false.
The bigger picture
Risk factors are commonly sorted into two groups, and knowing the difference is often the follow-up exam question:
- Modifiable risk factors are ones you can change through behavior or treatment: smoking, diet, physical inactivity, alcohol use, high blood pressure, and obesity. These are the targets of prevention.
- Non-modifiable risk factors cannot be changed: age, sex, genetics, family history, and race/ethnicity. You cannot alter them, but knowing them helps guide screening and monitoring.
Several other principles follow from the definition:
- Risk factors are probabilistic, not deterministic. You can have several and never develop the disease, and you can have none and still get it — the factor changes odds, not certainty.
- They often stack. Multiple risk factors together usually raise risk more than any one alone, which is why prevention targets several at once.
- They differ from protective factors, which decrease the likelihood of disease (exercise, vaccination, seatbelt use).
Understanding risk factors is the foundation of preventive medicine and public health: by identifying and reducing modifiable factors, individuals and communities can lower the probability of injury and disease even though no single factor can be eliminated entirely.
| Modifiable | Yes | Smoking, diet, inactivity, alcohol use, high blood pressure, obesity |
| Non-modifiable | No | Age, sex, genetics, family history, race/ethnicity |
| Protective (decreases risk) | Often yes | Exercise, vaccination, seatbelt use, healthy diet |
Frequently asked
What is an example of a risk factor?
Smoking is a classic example: it increases the likelihood of lung cancer, heart disease, and stroke. Other examples include high blood pressure, obesity, physical inactivity, and not wearing a seatbelt, each of which raises the probability of a specific injury or disease.
What is the difference between modifiable and non-modifiable risk factors?
Modifiable risk factors can be changed through behavior or treatment, such as smoking, diet, or blood pressure. Non-modifiable risk factors cannot be changed, such as age, sex, genetics, and family history. Prevention efforts focus on the modifiable ones.
Is a risk factor the same as a cause?
No. A cause directly produces a disease, while a risk factor only increases the probability that it will occur. A person can have a risk factor and never develop the disease, and someone without it can still get sick, so the two are not the same.
What are common risk factors for injury?
Common injury risk factors include not wearing a seatbelt, distracted or impaired driving, lack of protective equipment, fatigue, alcohol use, and unsafe working conditions. Each increases the likelihood that an injury will occur, though none guarantees it.
Can you have a risk factor and never get the disease?
Yes. Risk factors are probabilistic, meaning they raise the odds rather than determine the outcome. Many people with one or more risk factors never develop the associated disease, and some people with no known risk factors still do.