Aluminium metabolism in chronic renat failure: Environmental influences and regional differences in Norway

Many aspects of Al metabolism in chronic renal failure are poorly understood. A longitudinal study of serum Al concentrations in predialysis patients and healthy control subjects revealed very high values during the autumn of 1984 and 1985. Renal Al clearance was low during the autumnal spike in serum Al but increased substantially when the serum Al concentration declined. A second study confirmed that by using citric acid as a chelator, the gastrointestinal absorption of Al from Al(OH)₃ may be considerably augmented as reflected by increases in both serum Al concentrations and renal Al clearance. The individual differences in Al absorption in this study were large.The first study suggests the existence of an unidentified environmental factor, possibly water borne, with profound effects on Al absorption and excretion. The citric acid/Al(OH)₃ experiment suggests that the existence of such a factor is likely. The implications of these results are not known.A histomorphometric study of bone biopsies from 138 hemodialysis and 66 predialysis patients without clinical evidence of Al related disease, revealed Al deposits after staining with aurin tricarboxylic acid in 78% of the biopsies from the former and 24% of the latter patients. Serum Al concentrations did not differ between predialysis and hemodialysis patients with Al positive biopsies. Stratification of the hemodialysis patients, who came from all parts of Norway, revealed that patients living in regions with slightly Al contaminated drinking water (Al <30 g/L) had lower serum Al concentrations than patients from regions with highly contaminated water (Al >100 g/L). The prevalence of Al-positive biopsies was the same in both regions. Patients with Al-positive biopsies did not differ in serum Al level from those with Al-negative biopsies within the same region. Predialysis patients with Al-positive biopsies had significantly higher serum Al levels than predialysis patients with Al negative biopsies.Stainable Al deposits are commonly found in the bone of patients with chronic renal failure. Cross-sectionally obtained serum Al concentrations do not reflect the prevalence of stainable bone Al in renal patients but are related to the degree of Al contamination of water of the region.