Mammography and osteoporosis screening--clinical risk factors and their association with digital X-ray radiogrammetry bone mineral density.

The aim of this study was to study the association between digital X-ray radiogrammetry (DXR) T-score and clinical risk factors for osteoporosis. Women were recruited 2 d per wk at a single mammography screening center between year 2010 and 2012. Included women answered a questionnaire about risk factors for osteoporosis, and a radiograph of the nondominant hand was obtained for DXR analysis. Univariate associations between DXR T-score and risk factors were examined. A generalized linear regression model was fitted to independent variables with univariate associations at p<0.05. The multivariable model was reduced through manual backward elimination, with p>0.1 as the exclusion criterion. Seventy-six percent of the women chose to participate in the study (n=8810). The difference in number of daily mammograms performed on study vs nonstudy days was not significant. All univariate associations between DXR T-score and potential risk factors were highly significant. The multivariable model included height, weight, age, right-handedness, menopause before age 45, alcohol consumption, cortisone treatment, rheumatic disease, and age×smoking status. The coefficient of determination of the model was 0.37. The association between risk factors for osteoporosis and DXR T-score is similar to previously reported associations with dual-energy X-ray absorptiometry.