Skip navigation

Risk factors for hip fracture in women

Risk and reasons
So what can we do?

One of the most serious consequences of a fall in older persons is a hip fracture. Bandolier has previously highlighted the evidence (issues 25 and 49 ) that few people who have a fractured hip regain independent living, and the majority either die or have major disability as a consequence. Clearly a situation where more people fall will give rise to more people having a fractured hip.

Risk and reasons


While risk factors for hip fracture is a complex area, there is a review [1] giving a good overview of the problems, and beginning to outline the basis of a strategy for tackling future increases in the size of the problem. The factors in hip fracture risk are many - some related to the skeleton, others related to the risk of falling, and some more complex factors intermediate between both (Figure 1 and Table 1).

Figure 1: Risk Factors for hip fracture



Table 1: Risk factors for hip fracture in women
Risk factor Comment
Skeletal-related risk factors
Femoral neck geometry Longer hip axis (trochanter to pelvic rim) increases risk of fractured neck of femur
Microarchitecture Bone strength is associated with increased risk, and can be measured with broadband ultrasound attenuation. Risk increased about 7-fold in women above versus below median heel ultrasound measures
Mineral structure Fluoride may increase bone strength
Bone turnover Biochemical markers of increased bone turnover may be related to increased risk
Fall-related risk factors
Neuromuscular function Inability to rise from chair unaided five times, or on feet for fewer than 4 hours a day, inability to heel-to-toe walk all associated with increased risk
Cognitive impairment Poor mental health is a risk factor
Medications and drugs Sedative use, long-acting benzodiazepines increase risk. Caffeine consumption increases risk
Fall mechanics Fall on side highly increases risk
Complex risk factors
Age Most hip fractures occur after 75 years
Genetic background Maternal hip fracture increases risk. Some genetic markers are being studied which might be useful predictors of increased risk
Body size Being tall at a young age, being thin, or losing more than 10% of body weight since age 25 all increase the risk, while gaining weight may reduce risk
Physical activity High levels of physical activity, especially walking, are associated with reduced risk of fracture


While this review brings in a number of different studies to highlight each particular risk factor, the key study is a large examination of risk factors in 9,500 white women in the USA [2]. This examined women of at least 65 years and followed them every four months for a mean of over four years.

A searching statistical analysis identified the key factors, out of many, which were associated with increased risk of hip fracture (Table 2).

Table 2: Risk factors
Age 80 years or more
Maternal history of hip fracture
Any fracture since age of 50
Fair, poor, or very poor health
Previous hyperthyroidism
Anticonvulsant therapy
Current weight less than at age 25
Height at age 25 168 cm or more
More than 2 cups of coffee a day
On feet less than 4 hours a day
No walking for exercise
Unable to rise from chair without using arms
Lowest quartile of depth perception
Lowest quartile of contrast sensitivity
Resting pulse above 80 per minute

These were combined with the bone density at the heel to demonstrate just how some women could be identified at being particularly at risk. Fifteen percent of women had at least five risk factors, and had an incidence of hip fracture of 19 per 1000 woman years - or about a 2% risk every year. The 47% of women with two or fewer risk factors had a risk of 1 per 1000 woman years - or about 0.1% a year. When combined with bone density the risks were increased even further with those with the lowest bone density (Figure 2 ).

Figure 2: Interaction between risk factors for hip fracture and bone density



So what can we do?


It comes down to preventing hip fractures and preventing falls. For hip fractures the targets for interventions are shown in Figure 3. For people with skeletal problems, there are a number of therapeutic interventions - from bisphosphonates, to hormone replacement therapy, to the use of hip protectors, though exercise may be of importance also. The key is to identify those people most at risk.

Figure 3: Targets for reducing hip fracture rates in women



There is a Cochrane review of interventions to reduce the incidence of falling in the elderly [3]. This showed, on a limited number of trials with about 500 patients, that exercise alone or in conjunction with a health education programme were ineffective in protecting against falling. There was some evidence that interventions targeting multiple identified risk factors in individual patients might be effective.

Another important area to examine is that of prescribed drugs. What appears to be the first of a series of drugs and falls in over 60s [4] identifies many classes of psychotropic drugs as having an association with falls in non-randomised studies. Though frustratingly without any data other than odds ratios and relative risks, it reported that falls were common. For instance, in seven prospective studies of community-dwelling older people the annual incidence of falls ranged between 29% and 52%, and in two long-term studies looking at psychotropics the incidence of falls over six months was 58%.

We know that many drugs - antihypertensives, for instance, may have dizziness as an adverse effect. It is likely that many of the medicines prescribed for older people for very good reasons may contribute to falls - an additional source of harm.

So no simple answer, but much food for thought. Bandolier would love to know of any practical studies which have set out to reduce falls in older people at particularly high risk, apart from that in Bandolier 20 . A recent report [5] suggests that screening for fall-related risk factors need take only about five minutes. These, though, are for women. Falls and hip fractures in men could do with some more attention to derive risk factors for them, also.

References:


  1. B Allolio. Risk factors for hip fracture not related to bone mass and their therapeutic implications. Osteoporosis International 1999 Suppl 2: S9-S16.
  2. SR Cummings et al. Risk factors for hip fracture in white women. New England Journal of Medicine 1995 332: 767-73.
  3. LD Gillespie et al. Interventions to reduce the incidence of falling in the elderly. Cochrane Library 1998 issue 3.
  4. RM Leipzig et al. Drugs and falls in older people: a systematic review and meta-analysis: I. Psychotropic drugs. Journal of the American Geriatric Society 1999 47: 30-39.
  5. G Duward et al. Detection of risk of falling and hip fracture in women referred for bone densitometry. Lancet 1999 354: 220-1.
See also:
Gillespie LD, Gillespie WJ, Cumming R, Lamb SE, Rowe BH. Interventions for preventing falls in the elderly (Cochrane Review). In: The Cochrane Library, Issue 3, 1999.
Parker MJ, Gillespie LD, Gillespie WJ. Hip protectors for preventing hip fractures in the elderly (Cochrane Review). In: The Cochrane Library, Issue 3, 1999.
previous or next story in this issue