Fall risk factors are primarily classified into two broad categories: intrinsic factors (those originating inside the body) and extrinsic factors (those in the surrounding environment). Within those categories, risk factors are further sorted by whether they can be changed through intervention. This layered classification helps identify which risks you or a family member can actually do something about, and which ones simply signal that extra caution is needed.
Falls are the second leading cause of unintentional injury deaths worldwide, killing an estimated 684,000 people each year. Another 37.3 million falls require medical attention annually. Adults over 60 bear the greatest burden of fatal falls, and over 80% of fall-related deaths occur in low- and middle-income countries.
Intrinsic vs. Extrinsic: The Core Framework
The most widely used classification, including the one the CDC relies on, splits risk factors into intrinsic and extrinsic. Intrinsic factors are biological or psychological traits that make a person more likely to fall. Extrinsic factors are features of the physical environment or external circumstances that create opportunities for a fall to happen.
This distinction matters because the two categories call for completely different prevention strategies. Intrinsic risks often require medical treatment, exercise programs, or medication changes. Extrinsic risks call for practical fixes like better lighting, grab bars, or removing tripping hazards. Most falls result from a combination of both.
Intrinsic Risk Factors
Intrinsic factors span a wide range of physical and psychological conditions. The CDC’s list includes advanced age, previous falls, muscle weakness, gait and balance problems, poor vision, drops in blood pressure upon standing, and chronic conditions like arthritis, stroke, diabetes, Parkinson’s disease, and dementia.
Several of these deserve closer attention because of how strongly they drive fall risk. After age 30, strength and endurance decline by roughly 10% per decade. That gradual loss means a slip or stumble that a younger person would recover from can turn into a fall. Any lower limb disability increases the risk, and so does difficulty rising from a chair. People who are sedentary fall more than those who stay physically active, creating a cycle where reduced activity leads to further weakness.
Vision problems, including glaucoma, cataracts, reduced contrast sensitivity, and narrowed visual fields, all raise fall risk. Foot problems are often overlooked: pain when walking, calluses, toe deformities, and nail issues can all compromise balance. Poor nutrition plays a role too. Low body mass and vitamin D deficiency contribute to muscle weakness, fragile bones, and impaired walking patterns.
Cognitive disorders are a major factor. Dementia, poor memory, and reduced mental sharpness are all tied to higher fall rates. Depression stands out as particularly significant. Research published in the American Journal of Lifestyle Medicine found that about 40% of older adults reporting depression also reported at least one fall, making it the strongest risk factor after adjusting for other characteristics.
Fear of Falling
Fear of falling sits at the intersection of physical and psychological risk. Among people who have recently fallen, up to 70% report being afraid of falling again. Of those, roughly half limit or avoid physical and social activities because of that fear. The resulting isolation and inactivity weaken muscles and erode balance, which paradoxically increases the very risk they’re trying to avoid.
Extrinsic Risk Factors
Extrinsic factors are the environmental conditions that set the stage for a fall. The CDC identifies missing stair handrails, poor stair design, lack of bathroom grab bars, dim lighting or glare, obstacles and tripping hazards, slippery or uneven surfaces, and improper use of assistive devices like canes or walkers.
Inside the home, the National Institute on Aging highlights specific hazards room by room: throw rugs on smooth floors, books or shoes left in walking paths, furniture placed in high-traffic areas, wet bathroom surfaces without nonslip strips, electrical cords crossing walkways, and even pets underfoot. Poor lighting is a consistent theme. Stairwells, hallways, and bathrooms all benefit from night lights or motion-activated lighting, especially for people who get up during the night.
Medications as a Risk Factor
Medications occupy an unusual position in fall risk classification. They’re technically extrinsic (something introduced from outside the body), but they act on intrinsic systems like balance, blood pressure, and alertness. The CDC lists psychoactive medications as an extrinsic factor, while clinical literature often discusses them alongside other medical risk factors.
Taking four or more medications of any kind significantly raises fall risk. Certain drug classes are especially problematic. Benzodiazepines (commonly prescribed for anxiety and sleep) increase the risk of nighttime falls and hip fractures by 44%. Medications with strong anticholinergic properties, a category that includes certain older antihistamines, older antidepressants, bladder medications, and muscle relaxants, raise the likelihood of a fall or fracture by about 22%. Sedatives, heart rhythm drugs, diuretics, and antipsychotics also contribute substantially. The Beers Criteria, a widely referenced clinical guideline, flags many of these as medications to use cautiously or avoid in older adults because of their sedating effects, tendency to cause dizziness, and ability to trigger drops in blood pressure.
Modifiable vs. Non-Modifiable Factors
A second, equally important way to classify fall risk factors is by whether they can be changed. This framework is what drives practical prevention efforts.
Non-modifiable factors include age, sex (women fall more often than men), race (white adults report more falls than Black, Hispanic, and South Asian adults), and living alone. These characteristics can’t be altered, but they help identify who needs the most attention. For example, older women’s higher fall risk is partly explained by lower physical activity levels and less lower-body muscle strength compared to men, both of which are modifiable even though being female is not.
Potentially modifiable factors make up the larger and more actionable category. These include chronic conditions like diabetes, arthritis, osteoporosis, heart disease, and stroke. They also include functional limitations: difficulty running errands alone, difficulty dressing or bathing, and impaired walking. Depression, poor nutrition, medication use, sedentary behavior, and vision problems all fall into this group. Environmental hazards are almost entirely modifiable with relatively simple home modifications.
Research in the American Journal of Lifestyle Medicine found that the factors most strongly tied to falls, after adjusting for everything else, were depression, difficulty doing errands alone, and difficulty dressing or bathing. For fall injuries specifically, the top factors were depression, difficulty with self-care, and being in an unmarried partnership (likely a proxy for limited household support).
How These Classifications Are Used in Screening
Clinical screening tools translate these classification frameworks into practical scoring systems. The CDC’s STEADI (Stopping Elderly Accidents, Deaths, and Injuries) initiative uses a stepped approach. First, patients are screened annually with a 12-question tool or three key questions: Do you feel unsteady standing or walking? Do you worry about falling? Have you fallen in the past year? A score of 4 or higher on the questionnaire, or a “yes” to any of the three questions, flags someone as at risk.
Those screened as at risk move to a full assessment of modifiable risk factors, including gait, strength, medications, vision, foot health, vitamin D status, and home hazards. The Morse Fall Scale, commonly used in hospitals, takes about two minutes to complete and sorts patients into low, medium, or high risk categories.
The goal of all these classification systems is the same: to separate what can be fixed from what can’t, and to match each identified risk with the right type of intervention. Strength and balance exercises address muscle weakness. Medication reviews reduce drug-related dizziness. Grab bars and better lighting tackle environmental hazards. The classification isn’t just academic. It’s the foundation for deciding what to do next.