Prevalence of vitamin D depletion among morbidly obese patients seeking gastric bypass surgery.
BACKGROUND
Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery.


METHODS
We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D.


RESULTS
Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level <or= 20 ng/mL, was found in 166 patients (60%). An elevated PTH level was found in 48% of the patients. A significant inverse correlation was found between serum 25-hydroxyvitamin D level and both body mass index (r = .15; P = .012) and serum PTH level (r = .45; P < .001). Vitamin D depletion was significantly more prevalent in the African-American patients than in the white patients (91% vs 48%; P < .001).


CONCLUSIONS
Before gastric bypass surgery, a majority of morbidly obese patients have vitamin D depletion and secondary hyperparathyroidism. Studies evaluating the effects of gastric bypass on vitamin D metabolism must consider preoperative vitamin D nutritional status.
Carlin
Arthur M
AM
Department of Surgery, Henry Ford Hospital, Detroit, Michigan 48082, USA. acarlin1@hfhs.org
Rao
D Sudhaker
DS
Meslemani
Ali M
AM
Genaw
Jeffrey A
JA
Parikh
Nayana J
NJ
Levy
Shiri
S
Bhan
Arti
A
Talpos
Gary B
GB
D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D002118:Calcium / Q000097:blood; D016009:Chi-Square Distribution; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000601:surgery; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D000469:Alkaline Phosphatase; D002118:Calcium