Bone mineral density is not diminished by mild to moderate chronic renal insufficiency.
BACKGROUND
Persons with end-stage renal disease are at higher risk for osteopenia and hip fracture relative to the age-matched general population. Persons with mild to moderate chronic renal insufficiency (CRI) may have reduced bone mineral density (BMD) as a result of abnormalities in acid-base and vitamin D-parathyroid hormone homeostasis.


METHODS
We analyzed data on 13,848 adults aged 20 and above from the Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994). Regression models were used to determine the relationship between femoral BMD and renal function, the latter assessed using serum creatinine, blood urea nitrogen or Cockcroft-Gault creatinine clearance. To control for confounding, we fit sex-stratified models that adjusted for age, weight, height, race-ethnicity, menopausal status, estrogen use, activity level, family history of osteoporosis, diuretic use, and dietary intake of calcium and alcohol.


RESULTS
Although subjects with reduced renal function had significantly lower femoral BMD in unadjusted analysis, the association between CRI and bone mineral density was extinguished after adjustment in the multivariate models. In fact, controlling for only sex, age and weight was sufficient to extinguish any negative association between decreased renal function and decreased bone mineral density.


CONCLUSIONS
Although subjects with worse renal function have significantly lower femoral BMD, this association can be explained by confounding, principally by sex, age and weight. After taking into account the facts that women, older individuals and smaller individuals have less renal function and lower BMD, renal function itself is not independently associated with BMD.
Hsu
Chi-yuan
CY
Division of Nephrology, Prevention Science Group, University of California, San Francisco, San Francisco, California 94143-0532, USA. hsuchi@medicine.ucsf.edu
Cummings
Steven R
SR
McCulloch
Charles E
CE
Chertow
Glenn M
GM
D000328:Adult; D000368:Aged; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000453:epidemiology / Q000473:pathology; D001842:Bone and Bones / Q000473:pathology; D003404:Creatinine / Q000493:pharmacokinetics; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D010024:Osteoporosis / Q000453:epidemiology / Q000473:pathology; D012307:Risk Factors; D017678:Sex Distribution
D003404:Creatinine