Risk factors for hip fracture in a high incidence area: a case-control study from Oslo, Norway

The aim of this population-based matched case-control study was to evaluate the effect of risk factors for hip fracture in Oslo, Norway, which has some of the highest incidence rates ever reported. The study population comprised all non-institutionalized persons 50 years or older living in the catchment area of two Oslo hospitals, and cases were 246 patients admitted for hip fracture during a 1-year period. The controls were randomly selected from the study population, matched 1:1 for age and sex. Hip fracture was associated with lean body stature, smoking, low grip strength and decreased levels of physical activity, and inversely with length of education. In addition, hip fracture was inversely related to indicators of total food intake (number of meals per day, frequency of dinners, and slices of bread per day). A relation between hip fracture and low vitamin D intake was also suggested, whereas no association with dietary calcium intake was found. Finally, increased risk of fracture was seen in persons reporting two or more hospital admissions in the previous 2 years, and in those reporting weight reduction due to poor appetite during the previous year. In conclusion, the risk factor pattern for hip fracture was much the same in the elderly population of Oslo as previously described in other populations with a lower incidence of fracture. This study also indicates a relation between hip fracture and low food intake.