The aging process is associated with an increasing prevalence of
osteoporosis and
atherosclerosis, but it is uncertain if these two conditions are interrelated. Serum
paraoxonase-1 (PON1) is a
high-density lipoprotein (HDL) associated
enzyme that has been implicated in the pathogenesis of
atherosclerosis. Our aims of the study were to investigate (1) serum
paraoxonase and
arylesterase activities and,
lipid hydroperoxide (LOOH) levels in healthy postmenopausal women and (2) whether there were any associations between these
enzyme activities and bone mineral density (BMD). A total of 97 generally healthy postmenopausal women were enrolled in the study. BMD was measured at lumbar spine (LS) and femoral neck (FN) with dual energy X-ray absorptiometry. Serum
paraoxonase and
arylesterase activities were measured spectrophotometrically. LOOH levels were measured by iodometric assay. In this population, 50 (51%) women had BMD T scores < -2.5 at the LS and/or FN defined as
osteoporosis and 47 (49%) of them had normal BMDs. Serum
paraoxonase,
arylesterase, and LOOH activities were not significantly different between osteoporotic and nonosteoporotic postmenopausal women. There were also no correlations between
paraoxonase,
arylesterase, LOOH activities, and LS BMD and FN BMD. We conclude that there may be not good evidence to support a direct relationship between
osteoporosis and
atherosclerosis in these subjects. However, prospective studies with larger groups are needed to investigate this issue further.