Why do older people break their hip so easily?
Older bones are both thinner and more brittle, and reduced muscle strength makes falling more likely. This is a well-understood combination; the good news is that through exercise, adequate calcium and vitamin D, and avoiding smoking and prolonged corticosteroid use, you can work on several levers at once.
More than 90% of hip fractures in older people result from a fall in someone with fragile bones. That fragility has a name: osteoporosis. In this condition, bone strength decreases to the point where a simple misstep is enough to break the thighbone. Ageing itself is the most powerful driver: in both men and women, bone mass gradually declines as you get older.
Women face additional risk. After the menopause, oestrogen levels drop rapidly, and oestrogen protects bones. That loss is accompanied by accelerated bone loss that can persist for years. Men are also at risk, but later in life and to a lesser degree.
At the same time, it is not only the amount of bone that changes, but also its composition. Collagen, the connective tissue that keeps bone flexible, becomes stiffer with age. As a result, bone becomes more brittle: it is more likely to fracture under impact rather than absorbing some of the force. This mechanism is plausible, but the details are still being investigated.
Older people also lose muscle mass. Reduced muscle strength makes them unsteady on their feet and increases the risk of falling. When a younger person falls backwards, they automatically break the fall with outstretched arms. Older people often lack those reflexes, fall sideways or backwards onto a hard floor indoors, and can no longer cushion the impact.
Beyond age and sex, lifestyle factors also play a role: smoking, low levels of physical activity, a low intake of calcium and vitamin D, prolonged use of corticosteroids (powerful anti-inflammatory drugs), a small body frame and a family history of fractures all raise the risk. It is therefore a combination of progressively less bone, poorer bone quality, reduced muscle strength and a greater likelihood of falling that together leads to that fragile hip.
This answer draws on several reviews and one systematic review that summarise the well-established risk factors for hip fractures. For the main conclusions (osteoporosis, post-menopause, age-related bone loss) the evidence is robust and widely supported. The section on changes in bone composition and connective tissue rests on fewer studies and requires further research; the researchers themselves note that the evidence there has not yet fully crystallised.
How dangerous is a hip fracture for how long you live?
A hip fracture strongly raises the risk of dying for many years afterwards, especially in older men and people with other illnesses. Operating quickly (within 36 hours) appears to limit the harm.
Why do bones break more easily as you get older?
As you get older, bone breaks down faster than it is built up. Getting enough calcium and physical activity early in life, and not smoking, are the most concrete things you can do to lower that risk.
Does too little protein increase your risk of bone fractures as you age?
People with low protein in their diet demonstrably face a greater risk of bone fractures, and the difference is not small: hip fractures in particular occur noticeably more often with low protein intake. Make sure your daily diet consistently contains enough protein, especially as you get older.
Which type of training has the best-proven track record against bone loss in later life?
High-intensity resistance training (at least 70-85% of maximum load, two to three times per week, for at least eight to twelve months) works best for bone preservation. If you also want to address your fall risk and muscle strength, a combined programme of strength, balance and fitness is the smartest choice.
Why do bones become more brittle after menopause, and what can help?
Menopause causes bone loss because oestrogen disappears and disrupts the balance between bone breakdown and bone formation. Several proven treatments are available, but the choice between them is best discussed with your doctor.
How do I know whether my bones are strong enough (osteoporosis)?
With a bone density scan and, where appropriate, a fracture risk calculation, your GP can check whether your bones are strong enough, especially if you have risk factors or have previously broken a bone from a minor fall.