PTH and secondary hyperparathyroidism: Moreover, PA patients showed higher plasma PTH, lower serum 25(OH)-vitamin D levels, higher prevalence of vitamin D deficiency, and higher prevalence of osteopenia/osteoporosis than EH and controls. These observations support the hypothesis that bone loss and potentially fracture risk in PA patients arepotentially the result of aldosterone mediated hypercalciuria and the consecutive secondary hyperparathyroidism