Rodbro LL, et al. - Authors evaluated the impacts of parathyroid hormone (PTH) responses to vitamin D insufficiency on bone metabolism, density, and geometry. Findings suggested an association of high PTH levels with altered bone geometry, increased bone turnover, and reduced bone mineral density (BMD) at the spine. They noted a correlation of high compared to normal PTH levels with significantly lower plasma levels of 1,25(OH)2D, phosphate, but higher levels of osteocalcin and borderline higher levels of CTx. PTH was associated with osteocalcin and CTx.