However, recent studies have shown a high prevalence of ABD in treatment-naive patients, in early stages of CKD [84], where conditions that inhibit bone remodelling, such as resistance to the action of PTH, reduced levels of calcitriol, deficiency of sex hormones, diabetes, and uremic toxins such as indoxyl sulfate and sclerostin, are present [85, 86]. Here, PTH is linked to chronic kidney disease.