Abnormalities of vitamin D and calcium metabolism after surgical treatment of morbid obesity: a study of 136 patients.
OBJECTIVE
To assess the effect of bariatric surgical treatment of morbid obesity on bone mineral metabolism.


METHODS
We analyzed pertinent vitamin D and calcium metabolic variables in 136 patients who had undergone a malabsorptive bariatric operation. Measurements of bone mineral density (BMD), serum 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D [1,25-(OH)2D], parathyroid hormone (PTH), calcium, phosphorus, and alkaline phosphatase were performed. Statistical analyses assessed correlations among various factors.


RESULTS
The mean age (+/-SD) of the study group was 48.34 +/- 10.28 years. Their mean weight loss was 114.55 +/- 45.66 lb, and the mean duration since the bariatric surgical procedure was 54.02 +/- 51.88 months. Seventeen patients (12.5%) had a T-score of -2.5 or less, and 54 patients (39.7%) had a T-score between -1.0 and -2.5. Of 119 patients in whom serum 25-OHD was measured, 40 (34%) had severe hypovitaminosis D (25-OHD <8ng/mL), and 50 patients (42%) had low hypovitaminosis D (serum 25-OHD 8 to 20 ng/mL). The magnitude of weight loss correlated negatively with serum 25-OHD, calcium, phosphorus, and calcium x phosphorus product values and positively with serum alkaline phosphatase level. Serum 25-OHD and calcium concentrations correlated positively with the BMD. PTH, serum 1,25-(OH)2D, and alkaline phosphatase concentrations correlated negatively with the BMD, a reflection of the presence of secondary hyperparathyroidism, an accelerated conversion of 25-OHD to 1,25-(OH)2D by the elevated PTH levels, and increased osteoblastic activity. The mean daily vitamin D supplementation was 6,472 +/- 9,736 IU.


CONCLUSIONS
Hypovitaminosis D and subsequent bone loss are common in patients who have undergone a bariatric surgical procedure for morbid obesity. These patients require rigorous vitamin D supplementation.
Abbasi
Ali A
AA
Grunberger Diabetes Institute, Bloomfield Hills, Michigan, USA.
Amin
Mohammad
M
Smiertka
Jacquelyn K
JK
Grunberger
George
G
MacPherson
Bruce
B
Hares
Mustafa
M
Lutrzykowski
Marek
M
Najar
Ali
A
D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D015992:Body Mass Index; D015519:Bone Density; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery*; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood*; D015431:Weight Loss
C470125:PTH protein, human; D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D; D000469:Alkaline Phosphatase; D002118:Calcium