Recent trends in the incidence of hip fracture in Tottori Prefecture, Japan: changes over 32 years

Abstract

The incidence rate of hip fracture in Tottori Prefecture tended to increase until 2018 in men, but it did not increase after 2010 in women. By type of fracture, the incidence rate of femoral neck fractures also increased over time in men, but no other changes were observed from 2010.

Purpose: The aims of this study were to determine the sex-, age-, and fracture-type-specific incidence rates of hip fractures in Tottori Prefecture between 2007 and 2018 and to compare the results with our past results to identify changes over time.

Methods: All hip fractures in people aged 35 years or older living in Tottori Prefecture were surveyed from 2007 to 2018 throughout the entire prefecture, and the age- and sex-specific incidence rates were calculated. The incidence rates from 1986 to 1988, 1992 to 1994, 1998 to 2000, and 2004 to 2006 previously reported were used for the analysis.

Results: In men, the age-adjusted number of patients adjusted by demographic structure based on the mean incidence rate for each 3-year period from 1986 to 2018 showed an increase in incidence over time compared with the incidence for 1986-1988 (p < 0.001). In women, the incidence rose over time compared with the incidence for 1986-1988 until 2004-2006 (p < 0.001), and no further increase was observed from 2010. The age-specific incidence rates of neck fracture in men were higher in 2010-2012 and 2016-2018 compared with 2004-2006 (p < 0.001), but those in women showed no increase with time. Those of trochanteric fracture did not change over time in either men or women.

Conclusion: The hip fracture incidence rate in Tottori Prefecture, Japan, tended to increase until 2018 in men, but it did not increase after 2010 in women.

Keywords: Epidemiology; Hip fracture; Neck fracture; Trochanteric fracture.

Fig. 1

Age- and sex-specific incidence rates of hip fracture in Tottori Prefecture, Japan, from 2007 to 2018. Data are incidence rates per 100,000 person-years. Incidence rates from 2004 to 2006, which were previously reported [4], were used for comparison. (Refer actual data in Supplement 2 although the incidence rates for the age groups from 50 to 74 are too low to distinguish)

Fig. 2

Age-, sex-, and fracture-type-specific incidence rates from 2010 and 2018. Data are mean incidence rates per 100,000 person-years for three years with 3-year intervals. Incidence rates from 2004 to 2006, which were previously reported [4], were used for comparison

Fig. 3

The expected number of patients age-adjusted to the population structure. The expected number of patients (per 100,000 person-years) age-adjusted to the population structure in all of Japan in 1986 (35 years and older) was calculated every 3 years with 3-year intervals. Data until 2006, which were previously reported [–5], were used for comparison

Fig. 4

Monthly variations in the number of patients with hip fractures. Data are total number of patients during the observational period (from 2007 to 2018)