PTH and chronic kidney disease: As we mentioned previously, low PTH levels as a proxy of low-bone turnover in CKD patients have been associated with increased fracture risk (Coco and Rush, 2000; Nitta et al., 2004) but it remains a matter of debate whether low bone turnover per se or the disease causing low bone turnover accounts for the perceived ABD-induced risk of fracture or adverse outcomes (Evenepoel et al., 2021a; Nagy et al., 2022).