Age and sex-related calcium and strontium concentrations in different types of human bones

The concentrations of strontium and calcium were determined in different types of bones from 112 subjects (41 male and 71 female) with ages ranging from 35 to 97 years, subjected to bone surgeries carried out to repair fractures due to osteoporosis or to non-osteoporotic. The analytical method used for the determination of both elements in bone digests was atomic absorption spectrometry with a nitrous oxide/acetylene flame. The global mean concentrations were found to be 253.4 +/- 114.0 mg g(-1) and 32.98 +/- 14.91 mug g(-1), with values falling in the ranges 100-650.0 mg g(-1) and 16.00-81.00 mug g(-1) for calcium and strontium, respectively. The coefficients of variation were higher than 40% for both elements and both sexes, indicating great heterogeneity among data. The correlation of age, sex, type of bone and pathology with the concentrations of the elements studied, as well as with their ratio ((Sr)/(Ca)) was evaluated using the Statistical Analysis System software. Both elements showed a similar behavior for both sexes, although a great number of women are associated with lower mineral levels. There is also a significant decrease of both element concentrations after 55 and 45 years of age for male and female, respectively. There was no evidence of age and sex dependence with the pathologies under study although there are highly significant differences when related to the elements' concentrations. For both sexes, the mineral content of femur head is lower than the other bone types; apparently the demineralization has certain preference for those bones forming the hip.