Bone metabolism in obesity: changes related to severe overweight and dietary weight reduction.
A non-invasive evaluation of bone metabolism was performed in 44 morbidly obese patients before and after a mean weight loss of 22.4 kg (range 7.9-43.4 kg) after 2 months and a further weight loss of 7.3 kg after 8 months (0.8-20.0 kg). This weight reduction was obtained by a nutritionally adequate very-low-calorie diet. Before treatment the bone mineral content of the distal forearm was increased compared to normals (51.9 U vs. 43.7 U, p < 0.001). Bone formation was evaluated by serum alkaline phosphatase and serum osteocalcin. Serum alkaline phosphatase was increased (187.8 U/l vs 147.4 U/l, p < 0.001) while serum osteocalcin was lower than in the controls (0.67 nmol/l vs 0.98 nmol/l, p < 0.01). Bone resorption, as measured by the urinary hydroxyproline/creatinine ratio, was not increased in the obese patients (19.2 molar ratio x 10(-3) vs 16.7 molar ratio x 10(-3), NS). After 2 months, the bone mineral content had declined by 3.3%. Serum alkaline phosphatase remained unchanged (187.8 U/l vs 186.9 U/l, NS) but serum osteocalcin demonstrated a significant rise (3.94 nmol/l vs 10.53 nmol/l, p < 0.001), parallel to changes in the hydroxyproline/creatinine ratio (19.2 molar ratio x 10(-3) vs 25.2 molar ratio x 10(-3), p < 0.001). At 8 months, no further change in the bone mineral content was seen. The hydroxyproline/creatinine ratio did still increase (from 25.8 molar ratio x 10(-3) to 30.1 molar ratio x 10(-3), p < 0.05), while serum alkaline phosphatase and serum osteocalcin remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
Hyldstrup
L
L
Department of Endocrinology, Hvidovre Hospital, University of Copenhagen, Denmark.
Andersen
T
T
McNair
P
P
Breum
L
L
Transbøl
I
I
D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D015519:Bone Density; D001862:Bone Resorption / Q000503:physiopathology; D001842:Bone and Bones / Q000378:metabolism*; D002113:Calcification, Physiologic; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D004038:Diet, Reducing; D005260:Female; D006801:Humans; D006909:Hydroxyproline / Q000652:urine; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000178:diet therapy / Q000503:physiopathology*; D015675:Osteocalcin / Q000097:blood; D017697:Premenopause; D013997:Time Factors; D015431:Weight Loss / Q000502:physiology*
D015675:Osteocalcin; D003404:Creatinine; D000469:Alkaline Phosphatase; D006909:Hydroxyproline