Osteoporosis constitutes a major public health problem through its association with age-related fractures, most notably those of the hip, vertebrae and distal forearm. However, prospective studies have shown a heightened risk of almost all types of fracture in individuals with low bone mineral density (BMD). In the year 2000, there were an estimated 9 million osteoporotic fractures worldwide, of which 1.6 million were at the hip, 1.7 million at the forearm and 1.4 million were clinical (symptomatic) vertebral fractures. The combined annual cost of all osteoporotic fractures has been estimated to be $20 billion in the United States and €30 billion in the European Union [1
]. As life expectancy rises around the world, along with the number of elderly individuals in every geographic region, the incidence of hip fractures is estimated to reach 6.3 million in 2050; assuming a constant age-specific rate of fracture in men and women [2
]. However, substantial variation has been reported in hip fracture incidence rates around the world [1
]. Age-adjusted rates seem to be highest in Scandinavia and in North American populations, with almost seven-fold lower rates in Southern European countries [3
]. Hip fracture incidence is also lower in Asian and Latin American populations [4
] and rates seem to be lower in rural than in urban areas [6
In order to estimate the future global burden of hip and other age-related (or fragility) fractures in a more robust manner, it is important to analyse changes in fracture incidence rates, adjusted for demographic changes, in the world population. Projections of the future numerical burden of hip fracture are known to be highly sensitive to secular changes in age-adjusted incidence rates [8
]. Temporal trends in the age- and sex-adjusted incidence of hip fracture around the world were initially explored by Melton et al [9
], over the period 1928-1980 (). Incidence rates appeared to be rising steeply in the United States, as well as in other European centres. These increases were confirmed in subsequent studies from the United Kingdom [10
] and Scandinavia [11
]. The protracted follow-up period available in Rochester, MN, however, also suggested the intriguing possibility that age-adjusted incidence rates might have begun to plateau in women, from around 1955 onwards [9
]. These findings suggest an important role for environmental factors in the aetiology of hip fracture. However, the extent to which the risk factors studied to date (including smoking, alcohol consumption, physical activity levels, obesity and migration status), as well as the changing rates of risk assessment and treatment, contribute to these temporal trends remains uncertain.
Secular trends in the incidence of hip fracture; 1928-1982
This review will update the secular trends for hip fracture in Europe, North America, Oceania and Asia. The limited data on long-term incidence trends for vertebral, distal forearm and other fractures will also be covered. The review was conducted using the PubMed database and MeSH terms/keywords that were employed included “fracture” “incidence” “osteoporosis” “secular” or “trends”. Two co-authors (ZAC, CRH) conducted separate searches to ensure comprehensive identification of studies. All abstracts were reviewed to identify manuscripts of interest. Articles were chosen if they: (1) included incidence rates of fracture at any site over a defined time period; (2) reported directly estimated age-adjusted incidence rates from defined, broadly representative population samples; (3) used statistical tests to evaluate temporal trends; and (4) were published in the English language literature. The reference lists of these articles were examined for any other potentially relevant articles. Quality criteria included prospective ascertainment of fracture; appropriate definition of fracture site (ICD or other validated recording system); and determination of incidence over at least a one year period. Studies were considered eligible for review regardless of year of publication. In all, 51 articles were included and reviewed to ascertain the secular changes in osteoporotic fracture by country (). The majority of studies provided information on changes in hip fracture rates for men and women, but the data for secular trend in each gender were inconsistently supplied. Where available, trends in men generally resembled those in women. We therefore provide information in the table for both genders combined (age-standardised where possible). In those instances where data were only available for women, these are included in the table.
Annual change (%) in age-and sex-adjusted hip fracture incidence world wide*.