Risk factors for hip fractures. A review

Risk factors for hip fracture have been reviewed based on case-control and prospective follow-up studies. Falls with impact to the hip, the capacity of energy absorption in soft tissue, and bone strength are closely linked to the risk of hip fracture. Consistently documented risk factors are age, sex, race, low bone mass, low body weight, estrogen deficiency and earlier fracture. Other risk factors are tendency to fall, disability and immobilisation, low physical activity, use of psychotropic/anxiolytic/hypnotic drugs, use of corticosteroid, low calcium intake in the elderly, osteomalacia, thyreotoxicosis, cigarette smoking, chronic alcoholism, diabetes mellitus, insufficient sunlight exposure and a protective effect from thiazide diuretics. Evidence is lacking for risk factors such as heredity, nutrition and medical conditions. No information is available on the combined effects of the different risk factors. Risk estimation of hip fractures should focus on the risk of falls, the capacity of energy absorption and the bone strength. Recent studies indicate that the prevention of hip fractures is realistic, even in the elderly and definitely osteoporotic population when these fundamental risk factors are modified, which has been shown in controlled trials in nursing homes by vitamin D and calcium supplementation or by wearing external hip protectors.