Silent and progressing accumulation of aluminum in bone without definite histological osteomalacic aspects in chronic hemodialysis patients.

The aluminum (Al) contents of the tap water and the dialysis fluid in our center had proven to be less than 10 micrograms/l during more than 10 years. We evaluated the Al content, stainable Al, and the histomorphometry of the bone biopsy specimens from the 23 chronic renal failure patients on dialysis. The plasma Ca, P, Mg, ALP, C-PTH, and Al levels except calcitonin (CT, r = 0.442, p < 0.05) had no significant relationship to the hemodialysis (HD) duration. Their bone histologies were classified as osteitis fibrosa (OF) in 9, mild type (MILD) in 11, mixed type (MIXED) in 2, and osteomalacia (OM) in 1. The stainable Al% on the trabecular bone surface showed a positive correlation with HD duration (r = 0.569, p < 0.001), with the bone Al content (r = 0.455, p < 0.05), and with the bone Al/Ca ratio (r = 0.668, p < 0.01), respectively. The bone Al, Ca and Mg content did not correlated with HD duration and with plasma Al levels, although the bone Al/Ca ratio showed a strong correlation with HD duration (r = 0.675, p < 0.01) and with plasma Al levels (r = 0.719, p < 0.001). In the histomorphometric parameters, plasma Al levels, stainable Al, bone Al content, as well as bone Al/Ca ratio had no significant correlation with the osteomalacic aspects. Thus, our observations revealed that the Al accumulation in the bones was latent and progressing without definite osteomalacic changes, even though the dialysate Al concentration was under the critical level. Other Al invasion roots besides dialysis fluid should be regarded, including oral intake of Al-containing phosphate binders or other gastrointestinal medicines, as well as food content.