Studies over the last few decades have demonstrated geographic variation in the incidence of hip fracture across continents and among different parts of the same region. This paper studies the epidemiology of hip fracture worldwide, with special emphasis on the geographic variation among Asian countries. Using the Pubmed database, keywords that were employed included hip fracture, incidence rate, geographic variation, osteoporosis, and epidemiology. Articles were chosen based on the basis of (1) focus: studies that were said to specifically focus on geographic variation in hip fracture from different continents with a focus on Asia; (2) language: studies that were in English; (3) methods: studies that used statistical tests to examine hip fracture incidence rates. The highest hip fracture rates are seen in Scandinavian countries and the US and the lowest in African countries. Fracture rates are intermediate in Asian populations. Among different ethnic populations, the highest fracture rates are seen in Caucasians and the lowest in blacks. There is also a north-south gradient, particularly in Europe, where more hip fractures occur in North Europe compared to the South.
Osteoporosis is recognised as a major public health problem through its association with low trauma or fragility fracture. Osteoporotic hip fracture is an established health problem in the West over the last six decades and is increasingly being recognised as a growing problem in Asia [
This paper was conducted using the Pubmed database. Keywords that were employed included hip fracture, incidence rate, geographic variation, osteoporosis, and epidemiology. The articles were chosen based on the basis of (
Age-standardized hip fracture rates (per 100,000) across different continents and Asian countries are given in Table
Age standardized hip fracture rates (per 100,000) across different continents.
Continent | Country | Men | Women |
---|---|---|---|
North America | United States, Minnesota | 201.6 | 511.5 |
United States | 197.2 | 553.5 | |
Europe | England | 143.6 | 418.2 |
Sweden | 302.7 | 709.5 | |
Norway, | 352 | 763.6 | |
Oceania | New Zealand | 197 | 516 |
Australia | 187.8 | 504.2 | |
South America | Mexico | 98 | 169 |
Argentina | 137 | 405 | |
Africa | Cameroon | 43.7 | 52.1 |
Asia | China, Beijing | 87 | 97 |
Iran | 127.3 | 164.6 | |
Japan | 99.6 | 368 | |
Kuwait | 216.6 | 316 | |
Singapore | 152 | 402 | |
Hong Kong | 193 | 484.3 |
Age-standardized hip fracture rates (per 100,000) across Asian countries.
Worldwide geographic variation in hip fracture incidence.
In Europe, Scandinavia has the highest reported incidence of hip fracture worldwide. There are a large number of studies looking at the incidence as well as secular trends in this geographically northern region. The incidence rates vary from North to South Europe, the highest being in Sweden and Norway and the lowest in France and Switzerland. From Norway the reported age standardised annual incidence rates of hip fracture are 920 per 100,000 in women and 399.3 per 100,000 in men and those in Switzerland are 346 per 100,000 and 137.8 per 100,000 in women and men, respectively. Studies from Malmo, Sweden showed an exponential increase in hip fracture incidence from 1950 to 1985 in both men and women over age 50, increasing from an annual age-adjusted incidence of 150 to 390 per 100,000 in men and 300 to 830/100,000 in women [
The age-adjusted rates from Australia are 130/100,000 person years in men and 390/100,000 person years in women [
Limited data available from South American countries reveals inconsistent results. This may be due to different methods used for fracture incidence measurement. In a study published from Mexico in 2005, the annual rates of hip fracture in the two public health care systems were 169 in women and 98 in men per 10,000 person years [
A major study concluded that in a Japan population aged 35 years or older the crude incidence of hip fracture was 244.8 per 100,000 person years from 2004 to 2006, and the gender-specific incidence was 99.6 per 100,000 person years for men and 368 per 100,000 person years for women [
The majority of data from the Middle East is available from Iran from the Iranian Multicenter Study on Accidental Injuries [
Osteoporosis and fragility fractures are believed to be uncommon in Africa. To study this Zebaze et al. conducted a study in Cameroon by documenting all patients aged 35 years and older admitted to the two main urban hospitals in Cameroon following a diagnosis of fracture during two years [
To investigate the geographic variation in different parts of the world and whether this is genuine or related to error in data collection, Schwartz et al. [
The influence of ethnicity on risk of osteoporotic fractures was analysed by our group (unpublished). The rates vary considerably according to the geographic area and race and may vary widely within the same country and within populations of a given sex and race. In Europe, hip fracture rates vary 7-fold between countries. In general people who live in latitudes further from the equator seem to have a higher incidence of fracture. The highest rates of hip fracture are seen in Caucasians living in northern Europe, especially Scandinavians. A study from 1989 found that the age-adjusted 1-year cumulative incidence of hip fracture in Norway was 903/100,000 for women and 384/100,000 for men. The rates are intermediate in Asians, China and Kuwait, and the lowest in black populations. While studies in central Norway suggest a stabilisation in fracture rates in recent years, a Californian study published in 2004 reported a doubling of hip fracture rates in Hispanics while no significant change occurred among black or Asian men or women. Many of the lower incidence rates seen in the developing countries can be partially explained by lower life expectancy; in Latin America only 5.7% of the population is over 65. Reduced longevity may also be the explanation for the low fracture rates observed in Morocco.
The reasons for these geographic and ethnic variations are ill understood but factors which may be responsible are genetic factors and environmental factors. Those factors studied so far, such as alcohol consumption, smoking, activity levels, obesity, and migration status, have not explained these trends however. Reduced lifespan in African and Asian population may be one important attribute for the lower incidence of hip fracture in these regions. Further research is clearly needed to explain these important environmental factors.
To conclude, osteoporotic hip fractures are responsible for both morbidity and mortality among an elderly population and consume a large amount of health care resources in Europe and the USA. However, a recent decline in the hip fracture incidence in these regions is good news for health authorities but that is not true for the rest of the world. With a changing population profile and increasing elderly population in Asian countries there will be a shift of focus from Europe and US to Asia; health authorities need to prepare to face this challenge in the next four decades.