The kidney plays important roles in the regulation of mineral metabolism. It is not only the target organ of mineral regulating hormones, but also the main organ that activates vitamin D [1]. Accordingly, in CKD patients, various abnormalities develop in this system, such as secondary hyperparathyroidism [2, 3]. As partially depicted in this issue, Japanese researchers have substantially contributed to the elucidation of pathogenesis of these abnormalities, leading to the development of new therapeutic modalities [4–6].

Abnormal mineral metabolism in CKD has recently been renamed from renal osteodystrophy (ROD) to chronic kidney disease-mineral and bone disorder (CKD-MBD) as a syndrome [7]. Since CKD-MBD is a systemic disorder, we treat or prevent these abnormalities to decrease the risk of hard outcomes, such as cardiovascular disease, bone fracture and mortality. Among them, cardiovascular risk [8] has been mainly attributed to vascular calcification, however, thanks to the recent discoveries on the new roles of FGF23 [9, 10], CKD-MBD has expanded its concept, to further including left ventricular hypertrophy, heart failure, immune dysfunction, inflammation, anemia and iron deficiency. As for the bone abnormalities, recent reports suggest that abnormal bone quality also play important roles in bone fragility in CKD patients [11].

Care of CKD patients, especially for dialysis patients, has been traditionally quite intensive in Japan, which could have potentially contributed to the much better prognosis than other countries [12]. Achievement of strict target range of mineral parameters by Japanese guidelines [13, 14], especially focused on phosphorus [15, 16], may in part explain such a better prognosis [17]. In addition, because the number of kidney transplant recipients in Japan has been slowly growing, pre and post-transplant of CKD-MBD is also becoming another important topic in research and management [18].

There have been two active research meetings specialized on CKD-MBD research in Japan, i.e., The Research Meeting on Kidney and Metabolic Bone Disease (1983–2016) and The Japanese Society for Kidney Bone Disease (JSKBD) (1990–2016). To develop more intensive discussions among clinicians and researchers, these meetings have merged, and will restart from 2017 as Japan CKD-MBD Forum (Fig. 1).

Fig. 1
figure 1

Logo of the new research meeting for CKD-MBD in Japan (Copyright owned by Japan CKD-MBD Forum, with permission)

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On behalf of founding members, we hope discussions at this new ‘Japan CKD-MBD Forum’ will contribute to the elucidation of new pathogenetic mechanisms and to the development of globally relevant evidences, which contribute to future guidelines [19, 20].

Guest Editor

Masafumi Fukagawa, MD, PhD