Incidence of hip fracture over a 10-year period (1991-2000): reversal of a secular trend

Abstract

Introduction: Hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, disability, and costs. With the ageing of the population, a marked increase in the number of fractures is expected. Furthermore, many studies reveal an increase of the age-adjusted hip fracture incidence. We specifically examined secular changes in the incidence of hip fracture in women and men aged 50 years and over in the well-defined area of Geneva, Switzerland.

Materials and methods: All hip fractured patients were retrospectively identified from the computer medical records of the main hospital, which is receiving 95% of hip fractures occurring in a well-defined area.

Results: From 1991 to 2000, 4115 hip fractures were recorded in 2981 women and 822 men with a mean age (+/-S.D.) of 83.1+/-8.9 and 78.3+/-11.6 years, respectively. A second hip fracture occurred in 276 women (9.3%) and 36 men (4.4%), on average 2.1+/-1.9 (median 1.44) years after the first event without gender difference. The overall incidence of hip fractures was 455 (95% CI: 439-471) per 100,000 person-years in women and 153 (95% CI: 143-163) in men. The number of hip fractures remained constant (412 (95% CI: 397-426)), but the mean age of these patients increased each year by 0.13 year in women (p=0.019) and by 0.04 year in men (NS). Furthermore, the age-adjusted incidence of hip fractures, standardized to the 2000 Geneva population, decreased significantly by 1.4% (95% CI: -2.6 to -0.1) per year in women (p=0.021), but remained stable in men (0.5% (95% CI: -1.7 to +2.8) per year, p=0.66). The overall female/male ratio of hip fracture incidence was 2.99 (95% CI: 2.80-3.18, p<0.001) and significantly decreased by 0.07 (95% CI: -0.13 to -0.01) per year (p=0.024).

Conclusion: Despite an increase in the population at risk and in the mean age of hip fractured women, there was a significant decrease in age-adjusted incidence in women but not in men. These results may suggest a reversal of the previously observed secular trend.