Incidence of hip fracture in Niigata, Japan in 2004 and 2010 and the long-term trends from 1985 to 2010

We investigated the incidence of hip fracture in a population of patients ≥50 years old in 2004 and 2010 in Niigata City, Niigata Prefecture, Japan. We also investigated the long-term trends in the incidence of hip fracture from 1985 to 2010, using our previously reported survey results obtained from 1985 to 1999. In 2004 and 2010, the survey found 2,368 and 3,218 proximal femur fractures, respectively. The crude hip fracture incidence rates in 2004 and 2010 were 215.8 and 281.5 per 100,000 of population per year, respectively. For males, the incidence rates were 99.9 in 2004 and 126.3 in 2010; for females, the incidence rates were 311.0 and 410.7, respectively. In males aged 80–84 years, the incidence rate since 1999 has been decreasing, while that for males >85 years peaked in 2004. In females of all ages, the incidence rate was higher in 2010 than in all other survey periods, and in females >85 years, the incidence has increased the fastest. Additionally, the long-term changes in the age- and sex-standardized incidence each year using the 1985 population structure in Japan in females has been increasing, although it decreased in 1999. However, in males, the incidence in 2010 was not significantly different from that in 1994, although it has been increasing since 1999. Our study findings indicate that the age-specific incidence of hip fractures in the Niigata Prefecture of Japan has not plateaued in females, but that it may have done so in males; in addition, the number and incidence of hip fractures has been increasing.