Declining incidence of hip fractures and the extent of use of anti-osteoporotic therapy in Denmark 1997-2006

The incidence of hip fractures in Denmark declined by about 20% from 1997 to 2006 in both men and women aged 60 and over. The decrease in hip fracture rates was much too large to be explained by the extent of anti-osteoporotic medication used in the country. Introduction: The purpose of this study is to clarify (1) if hip fracture rates decline in Denmark despite low treatment rates and (2) if changes in age-specific rates could be explained by anti-osteoporotic medications. Methods: National registers were used to obtain incidence rates for hip fractures in men and women aged 60+ and aggregated national data on number of users of anti-osteoporotic medications for 1997-2006. The potential contribution of anti-osteoporotic treatment to prevented hip fractures was estimated. Results: Incidence rates declined by 20% in men and 22% in women. Use of specific anti-osteoporotic medications had increased from 1.8% in 60+-year-old women and 0.2% in 60+-year-old men to 7.3% and 1.3%, respectively. The decrease risk in men was nearly the same as in women, despite a six times lower treatment prevalence. The number of prevented hip fractures that could be attributed to therapy was 1.3% in men and 3.7% in women. Conclusions: The decrease in hip fractures is much too large to be explained by the extent of anti-osteoporotic medication. Interestingly, the decrease in fracture rates also applied to men, despite much lower treatment rates. Potential explanations include smoking habits, obesity, national home visit programmes, improved general health and vitamin D supplementation.