Thesis presents new opportunities to find those who need fracture prevention treatment among elderly women
May the risk for elderly women to suffer from fragility fractures be estimated more accurately than with the standard methods used in health care today, and how is this connected to nutrition and balance? This is the topic of Hans Lundin's thesis, which he presents at the Division of Family Medicine on April 8.
What's the main focus of your thesis?
My thesis is about finding new risk factors for osteoporotic fractures in elderly women, within the areas nutrition and balance, so that the risk for these fractures may be estimated more accurately. Fragility fractures are fractures that occur even though the amount of strain the skeleton was exposed to, would not be enough to cause a fracture in a healthy individual. Examples of fragility fractures are to get a fracture of a vertebra when lifting a bag of groceries, or to break the neck of the femur when falling on a flat surface.
The thesis contains four articles which are all based on a group of 351 elderly women in Bagarmossen, a Stockholm suburb, Sweden. Women have been tested for standing on one leg for up to 30 seconds, and a protein called insulin-like growth factor binding protein 1 (IGFBP-1) has been measured. The women have been followed for 10 years with regard to mortality and all types of skeletal fractures.
One aim of the thesis was to try to determine which women who had a high risk of future fractures, by measuring the time standing on one foot. A further aim was to see if high blood concentrations of IGFBP-1 resulted in an increased fracture risk and if so, was this relation independent of the blood concentrations of insulin-like growth factor 1 (IGF-I).
Which are the most important results?
The fewer seconds the women could stand on one leg (with eyes open), the higher risk they had to suffer a fragility fracture during the following 10 years. To use the time standing on one leg as an estimate of fracture risk, resulted in an accuracy of the risk assessment which was as good as the accuracy of the standard method FRAX which includes 11 to 12 risk factors instead of just one. We have not found any previous studies investigating a possible linear relationship between the time standing on one foot and fracture risk, or comparing the time standing on one foot to FRAX.
Also, the higher the blood concentrations of IGFBP-1, the higher the risk of a fragility fracture (a positive linear relation). This association could not be explained by differences in the concentrations of IGF-1. We have not found any previous studies investigating the relationship between IGFBP-1 and fracture risk, thus we are the first here too.
How can this new knowledge be useful for people, or contribute to improvement of their health?
Both the time on one leg and IGFBP-1 may easily be measured for example in primary care. You may use either of these risk factors to identify women at high risk of a fragility fracture. Those who have a high fracture risk should be offered preventive treatment and measures to reduce the risk of fractures.
Preventive treatment may be to train balance and muscle strength and/or to use medications. It may also be important to for example get a sturdy railing mounted along the basement stairs of your home. It is equally important to identify women who have a low risk of fractures so that they are not given any unnecessary preventive treatment or actions, and thus instead may be reassured on this point.
However, further studies are needed before we can determine whether or not the time on one leg or IGFBP-1 should be recommended as an alternative or supplement to FRAX, which is the method that is currently recommended for assessing fracture risk. The uncertainty mainly lies in the fact that we do not yet know if the relations found in our study also are valid for other parts of the population. So far, there is a shortcoming of studies showing what kind of treatment is most effective for those with poor balance on one leg or with high concentrations of IGFBP-1. Some individuals who have a high fracture risk according to one of these two methods, does not have high risk according to FRAX, and vice versa. It is yet not shown in any studies if the same treatments recommended to those with a high risk according to FRAX are also effective in individuals with a high fracture risk according to other risk factors.
What´s in the near future for you? Will you keep on conducting research?
I want to continue to do research as much as possible! During this year, I will, together with fellow scientists, write additional articles based on the results we have already found within the same project on which the thesis was based. We will also conduct new analyses on already collected material. I will continue to work as a teacher (Clinical Lecturer) at the Study Programme in Medicine at Karolinska Institutet. Directly after my dissertation I will also start to work with osteoporosis patients at Södersjukhuset in Stockholm.