Hip fracture risk
A total of 72 studies from 63 countries were selected for inclusion into the hip fracture resource. Studies selected are summarised in Tables 4, 5 and 6 of the Appendix together with the selection criteria and quality grades. There was a marked heterogeneity in hip fracture risk between countries. In women (Fig. 1), the lowest annual age-standardised incidences were found in Nigeria (2/100,000), South Africa (20), Tunisia (58) and Ecuador (73). The highest rates were observed in Denmark (574/100,000), Norway (563), Sweden (539) and Austria (501). Numerical data for other countries are given in Tables 4, 5 and 6 of the Appendix. Discounting the estimates from Nigeria (poor quality) and South Africa (rates for 1957–1963), there was approximately a 10-fold range in hip fracture incidence.
Within countries, the age-standardised incidence of hip fracture in men was approximately half that noted in women (Fig. 2). Thus where higher rates were observed in women, higher rates were found in men and vice versa. Omitting the studies from Africa, the highest annual incidence in men was seen in Denmark (290/100,000) and the lowest in Ecuador (35/100,000). There was a significant correlation between the rates in men and women (r = 0.82; p < 0.001). The correlation was similar when only high quality studies or only national studies were considered (data not shown).
The geographic distribution by fracture risk is shown for men, women and men and women combined in Figs. 3, 4 and 5, respectively. In men (Fig. 3), there was a swathe of high-risk countries extending from North Western Europe (Iceland, Ireland, Finland, Denmark, Sweden and Norway), both eastwards to the Russian Federation and downwards through to central Europe (Belgium, Germany, Austria and Switzerland) and thereafter to the south west (Greece, Hungary, Czech Republic and Slovakia) and onwards to Iran, Kuwait and Oman. Other high-risk countries for men were Singapore, Malta, Japan, Korea and Taiwan.
Regions of moderate risk included Oceania, China and India, Argentina and the countries of North America. If ethnic-specific rates were considered in USA, then the Hispanic, Asian and Black populations of men would be colour coded green. Low-risk countries included Latin America with the exception of Argentina, Africa and Saudi Arabia, the Iberian Peninsula and two countries in South East Asia (Indonesia and Thailand).
In women there was a broadly similar pattern as that seen in men. A notable difference in the distribution of high risk was that Russia was represented as moderate risk in women rather than high risk (in men). Also, the swathe of high-risk countries in Europe and beyond was more consolidated extending from North Western Europe (Iceland, UK, Ireland, Denmark, Sweden and Norway) through to central Europe (Belgium, Germany, Austria and Switzerland Italy) and thereafter to the south west (Greece, Hungary, Czech Republic, Slovakia, Slovenia) and onwards to Lebanon, Oman and Iran. Other high-risk countries for women were Hong Kong, Singapore, Malta and Taiwan. If ethnic-specific rates were considered in USA, then Hispanic, Asian and Black populations would be colour coded green but Caucasian women coded at high risk.
Regions of moderate risk included Oceania, the Russian Federation, the southern countries of Latin America and the countries of North America. Low-risk regions included the northern regions of Latin America, Africa, Jordan and Saudi Arabia, India, China, Indonesia and the Philippines. It is notable that in Europe, the majority of countries were categorised at high or moderate risk. Low risk was identified only in Croatia and Romania.
The consolidated map using age- and sex-standardised hip fracture rates is shown in Fig. 5. Note that the thresholds for categories of risk differ from those used in men and those used in women (which also differ from each other—see Table 1). With this proviso, the general pattern remained similar. Discordances in classification were relatively few. In the consolidated map, two countries coded low risk had been previously coded at intermediate risk (men in India and China). At the other extreme, one country coded as high risk had been previously coded at intermediate risk (men and women in Argentina).
As might be expected, there were more discordances in the moderate risk category. Six countries coded at moderate risk had been previously coded at low risk (men in Portugal, Thailand and Spain; women in Croatia, Jordan and Romania). Twelve countries coded at moderate risk had been previously coded at high risk (women in Hong Kong, Turkey, Italy, Lebanon and the UK; men in Kuwait, Japan, Russia, South Korea and Finland; men and women from Greece and Singapore).
A total of 45 country and/or ethnic models were available for inclusion into the distribution of fracture probability. The FRAX models used are summarised in Table 7 of the Appendix. There was a marked heterogeneity in the 10-year probability of a major fracture between countries. In men (Fig. 6), the lowest probabilities were found in Tunisia (1.9%), Ecuador (2.5%), Philippines (4.8%) and China (5.4%). The highest rates were observed in Denmark (23%), Sweden (21%), Norway (19%) and Switzerland (18%). Numerical data for other countries is given in Table 7 of the Appendix. Thus, there was a greater than 10-fold range in fracture probability.
Fracture probabilities were consistently higher in women than in men but the difference was relatively modest. On average, probabilities were 23% higher in women than in men. This contrasts, therefore, with hip fracture incidence which was twofold higher in women than in men. As expected, there was a close correlation between probabilities in men and those in women (r = 0.88; p < 0.001).
The geographic distribution by fracture risk is shown in men and women in Figs. 7 and 8, respectively. High-risk regions for men were Taiwan, Austria, USA (Caucasian), Switzerland, Norway, Sweden and Denmark. Those at low risk included Africa (Tunisia), Oceania, the Latin American countries of Ecuador and Colombia and several European countries (Spain, Poland, Romania, France and Turkey). Other countries at low risk were China, Lebanon, Philippines and the US Black population.
The general pattern of fracture probability in women was similar to that in men (Fig. 8). Discordances in classification were relatively few. Five countries coded as low risk in men were at intermediate risk for women (Poland, New Zealand, Romania, France and Turkey). Seven countries coded as moderate risk in men were coded at high risk in women (Japan, Belgium, Singapore, Canada, Malta, UK and Slovakia).