Hip fracture rates differ considerably between different countries and regions of the world. The rates vary more than 200-fold in women and more than 140-fold in men [
7]. The countries with the highest incidence are northern Europe (Norway, Sweden, Iceland, Ireland) followed by Central Europe (Denmark, Belgium, Germany, Switzerland, Austria) and eastern Europe (Czech Republic, Slovakia, Hungary) and the Middle East (Oman, Iran). Other high-risk countries are Argentina and Taiwan [
8]. The reasons for the huge geographic differences in hip fracture incidence are not well understood. Secular trends in hip fracture incidence which are described below in more detail and migration studies suggest environmental rather than genetic reasons [
8]. Various country indicators, such as socioeconomic status, development and urbanization are positively correlated with hip fracture risk [
7]; however, there is no clear evidence about an association between socioeconomic factors and fracture risk within countries [
9]. Urban areas have 20–60% higher incidences of hip fractures than rural areas [
10]. Hard surfaces due to soil sealing, lower physical activity and lower serum levels of vitamin D due to less sun exposure may contribute to the higher risks in urban areas and in countries with higher socioeconomic prosperity. Germany is a high-risk country for hip fractures with an incidence of approximately 130 fractures/100,000 citizens per year (standardized to the German population; [
11]). Considerable differences in hip fracture incidence have been reported for the different federal states [
12]. They do not follow an apparent pattern and the underlying reasons remain unclear. In addition, no consistent pattern was observed between area level socioeconomic conditions and hip fracture risk [
13].