Lactose and calcium absorption in postmenopausal osteoporosis.

The prevalence of lactase deficiency and the relationship between lactose and calcium malabsorption in postmenopausal osteoporosis has been assessed in 46 subjects. Malabsorption of lactose occurred in 25 (54%) of the subjects and was associated with a significantly lower milk intake. Malabsorption of calcium occurred in 11 (44%) of the lactase-deficient subjects and in 11 (52%) of normal lactose absorbers. There was no relationship between lactose and calcium malabsorption. Vertebral and forearm mineral densities were not significantly different between normal lactose absorbers and lactase-deficient subjects.