title: Bone as a possible target of chemical toxicity of natural uranium in drinking water.
abstract: Uranium accumulates in bone, affects bone metabolism in laboratory animals, and when ingested in drinking water increases urinary excretion of calcium and phosphate, important components in the bone structure. However, little is known about bone effects of ingested natural uranium in humans. We studied 146 men and 142 women 26-83 years of age who for an average of 13 years had used drinking water originating from wells drilled in bedrock, in areas with naturally high uranium content. Biochemical indicators of bone formation were serum osteocalcin and amino-terminal propeptide of type I procollagen, and a marker for bone resorption was serum type I collagen carboxy-terminal telopeptide (CTx). The primary measure of uranium exposure was uranium concentration in drinking water, with additional information on uranium intake and uranium concentration in urine. The data were analyzed separately for men and women with robust regression (which suppresses contributions of potential influential observations) models with adjustment for age, smoking, and estrogen use. The median uranium concentration in drinking water was 27 microg/L (interquartile range, 6-116 microg/L). The median of daily uranium intake was 36 microg (7-207 microg) and of cumulative intake 0.12 g (0.02-0.66 g). There was some suggestion that elevation of CTx (p = 0.05) as well as osteocalcin (p = 0.19) could be associated with increased uranium exposure (uranium in water and intakes) in men, but no similar relationship was found in women. Accordingly, bone may be a target of chemical toxicity of uranium in humans, and more detailed evaluation of bone effects of natural uranium is warranted.
authors.affiliation: STUK-Radiation and Nuclear Safety Authority, Research and Environmental Surveillance, Helsinki, Finland. paivi.kurttio@stuk.fi
authors.forename: Päivi
authors.initials: P
authors.lastname: Kurttio
authors.forename: Hannu
authors.initials: H
authors.lastname: Komulainen
authors.forename: Aila
authors.initials: A
authors.lastname: Leino
authors.forename: Laina
authors.initials: L
authors.lastname: Salonen
authors.forename: Anssi
authors.initials: A
authors.lastname: Auvinen
authors.forename: Heikki
authors.initials: H
authors.lastname: Saha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001862:Bone Resorption / Q000139:chemically induced*; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014501:Uranium / Q000506:poisoning*; D014881:Water Supply
chemical_list: D015415:Biomarkers; D014501:Uranium; D003094:Collagen