This list is from the Study of Osteoporotic Fractures (SOF) (Bauer). The study examined factors that could be asked on a questionnaire or measured at a clinic visit. The % changes shown are the difference in bone density between women with or without the factor; for continuous variables it is the % difference caused by approximately one standard deviation.
All of these factors together account for only 20-35% of the bone density.
The SOF study included only ambulatory Caucasian women volunteers older than age 65, and thus could not include some important risk factors, such as gender, race, or secondary osteoporosis
This graph is from the MrOS study, conducted by the same researches as the SOF study above, showing the independent factors associated with bone density (Cauley). There were 5,995 men older than 65 in this study. They were healthier than the general population, and only 4% of them smoked cigarettes. Therefore, some risk factors might not have been obvious in this group.
Move your mouse over the graph to see results for spine.
|Risk factors for Hip Fractures|
|This table shows a list of the most important epidemiological risk factors for hip fracture that are independently significant even when adjusted for bone density or history of previous fracture. |
Some important causes of secondary osteoporosis are not on this list because they are too uncommon (for example, myeloma) or because the clinical risk factors were associated with one of the factors on the list (for example, many diseases resulted in inability to get up from a chair).
A woman has a particularly high risk of hip fracture (2.7) if her mother broke her hip before age 80.
|Risk factors for the 1st vertebral fracture|
| The SOF (Nevitt) study also measured vertebrae on xrays taken at baseline and 3.7 years later in 7238 women. Overall 3.1% per year experienced their first new vertebral fracture. The rate was 3 times higher in women over 80 compared to women between 65-69 years old. The risk of a first fracture was 1.89 times higher for each standard deviation decrease in spine bone density (compared to age-matched women).
Other risk factors (adjusted for age) are shown in the table. It was not clear why there were so few vertebral fractures in women whose mother had a wrist fracture; the investigators thought it was a chance finding.
|These are the independent risk factors for non-vertebral fractures in men from the MrOS study. A long list of factors was related to fracture, but when they were all analyzed in a multi-variable model, only this short list was independently significant (Lewis)|