M. Finucane, G. Stevens, and M. Cowan, National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9??1 million participants, The Lancet, vol.377, issue.9765, pp.557-67, 2011.
DOI : 10.1016/S0140-6736(10)62037-5

K. Flegal, M. Carroll, B. Kit, and C. Ogden, Prevalence of Obesity and Trends in the Distribution of Body Mass Index Among US Adults, 1999-2010, JAMA, vol.307, issue.5, pp.491-498, 1999.
DOI : 10.1001/jama.2012.39

D. Withrow and D. Alter, The economic burden of obesity worldwide: a systematic review of the direct costs of obesity, Obesity Reviews, vol.8, issue.1, pp.131-172, 2011.
DOI : 10.1186/1472-6963-8-88

L. Sjöström, K. Narbro, and C. Sjöström, Effects of Bariatric Surgery on Mortality in Swedish Obese Subjects, New England Journal of Medicine, vol.357, issue.8, pp.741-52, 2007.
DOI : 10.1056/NEJMoa066254

H. Buchwald and D. Oien, Metabolic/Bariatric Surgery Worldwide 2011, Obesity Surgery, vol.292, issue.14, pp.427-463, 2013.
DOI : 10.1001/jama.292.14.1724

M. Shah, V. Simha, and A. Garg, Long-Term Impact of Bariatric Surgery on Body Weight, Comorbidities, and Nutritional Status, The Journal of Clinical Endocrinology & Metabolism, vol.91, issue.11, pp.4223-4254, 2006.
DOI : 10.1210/jc.2006-0557

B. Laferrère, J. Teixeira, and J. Mcginty, Hypocaloric Diet on Glucose and Incretin Levels in Patients with Type 2 Diabetes, The Journal of Clinical Endocrinology & Metabolism, vol.93, issue.7, pp.2479-85, 2008.
DOI : 10.1210/jc.2007-2851

L. Crowley, J. Seay, and G. Mullin, Late effects of gastric bypass for obesity, Am J Gastroenterol, vol.79, pp.850-60, 1984.

W. Goldner, O. Dorisio, T. Dillon, J. Mason, and E. , Severe Metabolic Bone Disease as a Long-Term Complication of Obesity Surgery, Obesity Surgery, vol.12, issue.5, pp.685-92, 2002.
DOI : 10.1381/096089202321019693

M. Collazo-clavell, A. Jimenez, S. Hodgson, and M. Sarr, OSTEOMALACIA AFTER ROUX-EN-Y GASTRIC BYPASS, Endocrine Practice, vol.10, issue.3, pp.195-203, 2004.
DOI : 10.4158/EP.10.3.195

D. Prisco, C. Levine, and S. , Metabolic Bone Disease after Gastric Bypass Surgery for Obesity, The American Journal of the Medical Sciences, vol.329, issue.2
DOI : 10.1097/00000441-200502000-00001

A. Al-shoha, S. Qiu, S. Palnitkar, and S. Rao, Osteomalacia with Bone Marrow Fibrosis Due to Severe Vitamin D Deficiency After a Gastrointestinal Bypass Operation for Severe Obesity, Endocrine Practice, vol.15, issue.6
DOI : 10.4158/EP09050.ORR

A. Berarducci, K. Haines, and M. Murr, Incidence of bone loss, falls, and fractures after Roux-en-Y gastric bypass for morbid obesity, Applied Nursing Research, vol.22, issue.1, pp.35-41, 2009.
DOI : 10.1016/j.apnr.2007.03.004

A. Lalmohamed, D. Vries, F. Bazelier, and M. , Risk of fracture after bariatric surgery in the United Kingdom: population based, retrospective cohort study, BMJ, vol.345, issue.aug03 1, p.5085, 2012.
DOI : 10.1136/bmj.e5085

M. Premaor, R. Parker, and S. Cummings, Predictive value of FRAX for fracture in obese older women, Journal of Bone and Mineral Research, vol.96, issue.9765, pp.188-95, 2013.
DOI : 10.1210/jc.2011-0076

N. Vilarrasa, S. Jose, P. Garcia, and I. , Evaluation of Bone Mineral Density Loss in Morbidly Obese Women After Gastric Bypass: 3-Year Follow-Up, Obesity Surgery, vol.12, issue.suppl 2, pp.465-72, 2011.
DOI : 10.1359/jbmr.1997.12.11.1908

G. Weryha, J. Leclère, and D. Régent, Bone densitometry : technical principles and practical value, Ann Endocrinol, vol.52, pp.298-304, 1991.

M. Ott, P. Fanti, and H. Malluche, Biochemical Evidence of Metabolic Bone Disease in Women Following Roux-Y Gastric Bypass for Morbid Obesity, Obesity Surgery, vol.2, issue.4, pp.341-349, 1992.
DOI : 10.1381/096089292765559936

L. Goode, R. Brolin, H. Chowdhury, and S. Shapses, Bone and Gastric Bypass Surgery: Effects of Dietary Calcium and Vitamin D, Obesity Research, vol.16, issue.1, pp.40-47, 2004.
DOI : 10.1359/jbmr.2001.16.1.141

J. Valderas, S. Velasco, and S. Solari, Increase of Bone Resorption and the Parathyroid Hormone in Postmenopausal Women in the Long-term after Roux-en-Y Gastric Bypass, Obesity Surgery, vol.84, issue.8, pp.1132-1140, 2009.
DOI : 10.1007/s11695-009-9890-y

J. Gomez, N. Vilarrasa, and C. Masdevall, Regulation of Bone Mineral Density in Morbidly Obese Women: A Cross-sectional Study in Two Cohorts Before and After Bypass Surgery, Obesity Surgery, vol.75, issue.3, pp.345-50, 2009.
DOI : 10.1079/PNS200194

J. Johnson, J. Maher, and I. Samuel, Effects of Gastric Bypass Procedures on Bone Mineral Density, Calcium, Parathyroid Hormone, and Vitamin D, Journal of Gastrointestinal Surgery, vol.9, issue.8, pp.1106-1117, 2005.
DOI : 10.1016/j.gassur.2005.07.012

P. Coates, J. Fernstrom, and M. Fernstrom, Gastric Bypass Surgery for Morbid Obesity Leads to an Increase in Bone Turnover and a Decrease in Bone Mass, The Journal of Clinical Endocrinology & Metabolism, vol.89, issue.3, pp.1061-1066, 2004.
DOI : 10.1210/jc.2003-031756

J. Fleischer, E. Stein, and M. Bessler, The Decline in Hip Bone Density after Gastric Bypass Surgery Is Associated with Extent of Weight Loss, The Journal of Clinical Endocrinology & Metabolism, vol.93, issue.10, pp.3735-3775, 2008.
DOI : 10.1210/jc.2008-0481

T. Mahdy, S. Atia, and M. Farid, Effect of Roux-en Y Gastric Bypass on Bone Metabolism in Patients with Morbid Obesity: Mansoura Experiences, Obesity Surgery, vol.20, issue.suppl, pp.1526-1557, 2008.
DOI : 10.12659/MSM.430365

F. Carrasco, M. Ruz, and P. Rojas, Changes in Bone Mineral Density, Body Composition and Adiponectin Levels in Morbidly Obese Patients after Bariatric Surgery, Obesity Surgery, vol.243, issue.1, pp.41-47, 2009.
DOI : 10.1002/j.1550-8528.1999.tb00404.x

N. Vilarrasa, J. Gomez, and I. Elio, Evaluation of Bone Disease in Morbidly Obese Women After Gastric Bypass and Risk Factors Implicated in Bone Loss, Obesity Surgery, vol.12, issue.7, pp.860-866, 2009.
DOI : 10.1007/s11695-009-9843-5

D. Casagrande, G. Repetto, and C. Mottin, Changes in Bone Mineral Density in Women Following 1-Year Gastric Bypass Surgery, Obesity Surgery, vol.19, issue.10, pp.1287-92, 2012.
DOI : 10.1007/s11695-009-9927-2

E. Stein, A. Carrelli, and P. Young, Bariatric Surgery Results in Cortical Bone Loss, The Journal of Clinical Endocrinology & Metabolism, vol.98, issue.2, pp.541-550, 2013.
DOI : 10.1210/jc.2012-2394

V. Mach, M. Stoeckli, R. Bilz, and S. , Changes in bone mineral content after surgical treatment of morbid obesity, Metabolism, vol.53, issue.7, pp.918-939, 2004.
DOI : 10.1016/j.metabol.2004.01.015

C. Riedt, R. Brolin, and R. Sherrell, True Fractional Calcium Absorption is Decreased After Roux-En-Y Gastric Bypass Surgery*, Obesity, vol.12, issue.11, pp.1940-1948, 2006.
DOI : 10.1152/japplphysiol.00264.2003

URL : http://onlinelibrary.wiley.com/doi/10.1038/oby.2006.226/pdf

C. Bruno, A. Fulford, and J. Potts, Serum Markers of Bone Turnover Are Increased at Six and 18 Months after Roux-En-Y Bariatric Surgery: Correlation with the Reduction in Leptin, The Journal of Clinical Endocrinology & Metabolism, vol.95, issue.1, pp.159-66, 2010.
DOI : 10.1210/jc.2009-0265

A. Carlin, D. Rao, and K. Yager, Treatment of vitamin D depletion after Roux-en-Y gastric bypass: a randomized prospective clinical trial, Surgery for Obesity and Related Diseases, vol.5, issue.4, pp.444-453, 2009.
DOI : 10.1016/j.soard.2008.08.004

M. Coupaye, M. Breuil, and P. Rivière, Serum Vitamin D Increases with Weight Loss in Obese Subjects 6??Months After Roux-en-Y Gastric Bypass, Obesity Surgery, vol.95, issue.4, pp.486-93, 2013.
DOI : 10.1210/jc.2009-0265

A. Carlin, D. Rao, and K. Yager, Effect of gastric bypass surgery on vitamin D nutritional status, Surgery for Obesity and Related Diseases, vol.2, issue.6, pp.638-680, 2006.
DOI : 10.1016/j.soard.2006.09.003

J. Jin, A. Robinson, and P. Hallowell, Increases in parathyroid hormone (PTH) after gastric bypass surgery appear to be of a secondary nature, Surgery, vol.142, issue.6, pp.914-934, 2007.
DOI : 10.1016/j.surg.2007.09.023

M. Nelson, L. Bolduc, and M. Toder, Correction of preoperative vitamin D deficiency after Roux-en-Y gastric bypass surgery, Surgery for Obesity and Related Diseases, vol.3, issue.4, pp.434-441, 2007.
DOI : 10.1016/j.soard.2007.02.007

J. Jin, T. Stellato, and P. Hallowell, Utilization of Preoperative Patient Factors to Predict Postoperative Vitamin D Deficiency for Patients Undergoing Gastric Bypass, Journal of Gastrointestinal Surgery, vol.142, issue.6, pp.1052-1059, 2009.
DOI : 10.1007/s11605-009-0847-1

E. Aasheim, S. Björkman, and T. Søvik, Vitamin status after bariatric surgery: a randomized study of gastric bypass and duodenal switch, The American Journal of Clinical Nutrition, vol.353, issue.1, pp.15-22, 2009.
DOI : 10.1080/1102680410003794

C. Signori, K. Zalesin, and B. Franklin, Effect of Gastric Bypass on Vitamin D and Secondary Hyperparathyroidism, Obesity Surgery, vol.12, issue.1, pp.949-52, 2010.
DOI : 10.1111/j.1365-2265.2006.02502.x

L. Flores, M. Osaba, M. Andreu, and A. , Calcium and Vitamin D Supplementation after Gastric Bypass Should Be Individualized to Improve or Avoid Hyperparathyroidism, Obesity Surgery, vol.18, issue.6, pp.738-781, 2010.
DOI : 10.4158/EP.14.3.318

P. Pramyothin, R. Biancuzzo, and Z. Lu, Vitamin D in Adipose Tissue and Serum 25-Hydroxyvitamin D After Roux-en-Y Gastric Bypass, Obesity, vol.43, issue.11, pp.2228-2262, 2011.
DOI : 10.1038/oby.2007.23

L. Beckman, C. Earthman, and W. Thomas, Serum 25(OH) Vitamin D Concentration Changes After Roux-en-Y Gastric Bypass Surgery, Obesity, vol.20, issue.12, pp.1-8, 2013.
DOI : 10.1038/oby.2011.404

URL : http://onlinelibrary.wiley.com/doi/10.1002/oby.20464/pdf

D. Avgerinos, M. Leitman, and R. Martinez, Evaluation of Markers for Calcium Homeostasis in a Population of Obese Adults Undergoing Gastric Bypass Operations, Journal of the American College of Surgeons, vol.205, issue.2, pp.294-301, 2007.
DOI : 10.1016/j.jamcollsurg.2007.02.078

M. Digiorgi, A. Daud, and W. Inabnet, Markers of Bone and Calcium Metabolism Following Gastric Bypass and Laparoscopic Adjustable Gastric Banding, Obesity Surgery, vol.29, issue.3, pp.1144-1152, 2008.
DOI : 10.1007/s11695-007-9408-4

W. Goldner, J. Stoner, and E. Lyden, Finding the Optimal Dose of Vitamin D Following Roux-en-Y Gastric Bypass: A Prospective, Randomized Pilot Clinical Trial, Obesity Surgery, vol.12, issue.6, pp.173-182, 2009.
DOI : 10.4158/EP.10.3.195

E. Lin, D. Armstrong-moore, and Z. Liang, Contribution of Adipose Tissue to Plasma 25-Hydroxyvitamin D Concentrations During Weight Loss Following Gastric Bypass Surgery, Obesity, vol.86, issue.3, pp.588-94, 2011.
DOI : 10.1007/s11695-008-9698-1

J. Sanchez-hernandez, J. Ybarra, and I. Gich, Effects of Bariatric Surgery on Vitamin D Status and Secondary Hyperparathyroidism: A Prospective Study, Obesity Surgery, vol.15, issue.10, pp.1389-95, 2005.
DOI : 10.1381/096089205774859182

J. Ybarra, J. Sanchez-hernandez, and I. Gich, Unchanged Hypovitaminosis D and Secondary Hyperparathyroidism in Morbid Obesity after Bariatric Surgery, Obesity Surgery, vol.15, issue.3, pp.330-335, 2005.
DOI : 10.1381/0960892053576758

D. Mdf, M. Diniz, and S. Sanches, Elevated serum parathormone after Rouxen-Y gastric bypass, Obes Surg, vol.14, pp.1222-1228, 2004.

Y. Youssef, W. Richards, and N. Sekhar, Risk of secondary hyperparathyroidism after laparoscopic gastric bypass surgery in obese women, Surgical Endoscopy, vol.15, issue.8, pp.1393-1399, 2007.
DOI : 10.1016/S0025-7125(16)30696-4

E. Fish, G. Beverstein, and D. Olson, Vitamin D Status of Morbidly Obese Bariatric Surgery Patients, Journal of Surgical Research, vol.164, issue.2, pp.198-202, 2010.
DOI : 10.1016/j.jss.2010.06.029

H. Bischoff-ferrari, E. Giovannucci, and W. Willett, Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes, The American Journal of Clinical Nutrition, vol.61, issue.4, pp.18-28, 2006.
DOI : 10.1093/ajcn/61.3.638S

E. Grethen, R. Mcclintock, and C. Gupta, Vitamin D and Hyperparathyroidism in Obesity, The Journal of Clinical Endocrinology & Metabolism, vol.96, issue.5, pp.1320-1326, 2011.
DOI : 10.1210/jc.2010-2202

S. Parikh, M. Edelman, and G. Uwaifo, The Relationship between Obesity and Serum 1,25-Dihydroxy Vitamin D Concentrations in Healthy Adults, The Journal of Clinical Endocrinology & Metabolism, vol.89, issue.3, pp.1196-1205, 2004.
DOI : 10.1210/jc.2003-031398

J. Wortsman, L. Matsuoka, and T. Chen, Decreased bioavailability of vitamin D in obesity, The American Journal of Clinical Nutrition, vol.58, issue.3, pp.690-693, 2000.
DOI : 10.1093/ajcn/58.6.882

E. Aarts, L. Van-groningen, and R. Horst, Vitamin D absorption: consequences of gastric bypass surgery, European Journal of Endocrinology, vol.87, issue.6, pp.827-859, 2011.
DOI : 10.1007/BF01311670

M. Holick, R. Biancuzzo, and T. Chen, in Maintaining Circulating Concentrations of 25-Hydroxyvitamin D, The Journal of Clinical Endocrinology & Metabolism, vol.93, issue.3, pp.677-81, 2008.
DOI : 10.1210/jc.2007-2308

J. Johnson, J. Maher, and E. Denaria, The Long-term Effects of Gastric Bypass on Vitamin D Metabolism, Annals of Surgery, vol.243, issue.5, pp.701-706, 2006.
DOI : 10.1097/01.sla.0000216773.47825.c1

P. Tondapu, D. Provost, and B. Adams-huet, Comparison of the Absorption of Calcium Carbonate and Calcium Citrate after Roux-en-Y Gastric Bypass, Obesity Surgery, vol.15, issue.3, pp.1256-61, 2009.
DOI : 10.1038/oby.2006.226

J. Mechanick, R. Kushner, and H. Sugerman, The Obesity Society, and American Society for Metabolic and Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient, American Association of Clinical Endocrinologists Obesity (Silver Spring), vol.17, issue.1, pp.1-70, 2009.

O. Ziegler, M. Sirveaux, and L. Brunaud, Medical follow up after bariatric surgery: nutritional and drug issues General recommendations for the prevention and treatment of nutritional deficiencies, Diabetes & Metabolism, vol.35, issue.6, pp.544-57, 2009.
DOI : 10.1016/S1262-3636(09)73464-0

S. Hui, S. Gao, and X. Zhou, Universal Standardization of Bone Density Measurements: A Method with Optimal Properties for Calibration Among Several Instruments, Journal of Bone and Mineral Research, vol.57, issue.9, pp.1463-70, 1997.
DOI : 10.1359/jbmr.1997.12.9.1463

Y. Lu, T. Fuerst, and S. Hui, Standardization of Bone Mineral Density at Femoral Neck, Trochanter and Ward's Triangle, Osteoporosis International, vol.12, issue.6, pp.438-482, 2001.
DOI : 10.1007/s001980170087

B. Fan, X. Wu, and M. Levine, Cross Calibration of Whole Body Scans Between GE-Lunar and Hologic Systems, Journal of Clinical Densitometry, vol.12, issue.3, p.385, 2009.
DOI : 10.1016/j.jocd.2009.03.068

S. Sordet, M. D. , D. Quilliot, and M. D. , PhD 2

M. Finucane, G. Stevens, and M. Cowan, National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9??1 million participants, The Lancet, vol.377, issue.9765, pp.557-67, 2011.
DOI : 10.1016/S0140-6736(10)62037-5

K. Flegal, M. Carroll, B. Kit, and C. Ogden, Prevalence of Obesity and Trends in the Distribution of Body Mass Index Among US Adults, 1999-2010, JAMA, vol.307, issue.5, pp.491-498, 1999.
DOI : 10.1001/jama.2012.39

D. Withrow and D. Alter, The economic burden of obesity worldwide: a systematic review of the direct costs of obesity, Obesity Reviews, vol.8, issue.1, pp.131-172, 2011.
DOI : 10.1186/1472-6963-8-88

L. Sjöström, K. Narbro, and C. Sjöström, Effects of Bariatric Surgery on Mortality in Swedish Obese Subjects, New England Journal of Medicine, vol.357, issue.8, pp.741-52, 2007.
DOI : 10.1056/NEJMoa066254

H. Buchwald and D. Oien, Metabolic/Bariatric Surgery Worldwide 2011, Obesity Surgery, vol.292, issue.14, pp.427-463, 2013.
DOI : 10.1001/jama.292.14.1724

M. Shah, V. Simha, and A. Garg, Long-Term Impact of Bariatric Surgery on Body Weight, Comorbidities, and Nutritional Status, The Journal of Clinical Endocrinology & Metabolism, vol.91, issue.11, pp.4223-4254, 2006.
DOI : 10.1210/jc.2006-0557

B. Laferrère, J. Teixeira, and J. Mcginty, Hypocaloric Diet on Glucose and Incretin Levels in Patients with Type 2 Diabetes, The Journal of Clinical Endocrinology & Metabolism, vol.93, issue.7, pp.2479-85, 2008.
DOI : 10.1210/jc.2007-2851

L. Crowley, J. Seay, and G. Mullin, Late effects of gastric bypass for obesity, Am J Gastroenterol, vol.79, pp.850-60, 1984.

W. Goldner, O. Dorisio, T. Dillon, J. Mason, and E. , Severe Metabolic Bone Disease as a Long-Term Complication of Obesity Surgery, Obesity Surgery, vol.12, issue.5, pp.685-92, 2002.
DOI : 10.1381/096089202321019693

M. Collazo-clavell, A. Jimenez, S. Hodgson, and M. Sarr, OSTEOMALACIA AFTER ROUX-EN-Y GASTRIC BYPASS, Endocrine Practice, vol.10, issue.3, pp.195-203, 2004.
DOI : 10.4158/EP.10.3.195

D. Prisco, C. Levine, and S. , Metabolic Bone Disease after Gastric Bypass Surgery for Obesity, The American Journal of the Medical Sciences, vol.329, issue.2
DOI : 10.1097/00000441-200502000-00001

A. Al-shoha, S. Qiu, S. Palnitkar, and S. Rao, Osteomalacia with Bone Marrow Fibrosis Due to Severe Vitamin D Deficiency After a Gastrointestinal Bypass Operation for Severe Obesity, Endocrine Practice, vol.15, issue.6
DOI : 10.4158/EP09050.ORR

A. Berarducci, K. Haines, and M. Murr, Incidence of bone loss, falls, and fractures after Roux-en-Y gastric bypass for morbid obesity, Applied Nursing Research, vol.22, issue.1, pp.35-41, 2009.
DOI : 10.1016/j.apnr.2007.03.004

A. Lalmohamed, D. Vries, F. Bazelier, and M. , Risk of fracture after bariatric surgery in the United Kingdom: population based, retrospective cohort study, BMJ, vol.345, issue.aug03 1, p.5085, 2012.
DOI : 10.1136/bmj.e5085

M. Premaor, R. Parker, and S. Cummings, Predictive value of FRAX for fracture in obese older women, Journal of Bone and Mineral Research, vol.96, issue.9765, pp.188-95, 2013.
DOI : 10.1210/jc.2011-0076

N. Vilarrasa, S. Jose, P. Garcia, and I. , Evaluation of Bone Mineral Density Loss in Morbidly Obese Women After Gastric Bypass: 3-Year Follow-Up, Obesity Surgery, vol.12, issue.suppl 2, pp.465-72, 2011.
DOI : 10.1359/jbmr.1997.12.11.1908

G. Weryha, J. Leclère, and D. Régent, Bone densitometry : technical principles and practical value, Ann Endocrinol, vol.52, pp.298-304, 1991.

M. Ott, P. Fanti, and H. Malluche, Biochemical Evidence of Metabolic Bone Disease in Women Following Roux-Y Gastric Bypass for Morbid Obesity, Obesity Surgery, vol.2, issue.4, pp.341-349, 1992.
DOI : 10.1381/096089292765559936

L. Goode, R. Brolin, H. Chowdhury, and S. Shapses, Bone and Gastric Bypass Surgery: Effects of Dietary Calcium and Vitamin D, Obesity Research, vol.16, issue.1, pp.40-47, 2004.
DOI : 10.1359/jbmr.2001.16.1.141

J. Valderas, S. Velasco, and S. Solari, Increase of Bone Resorption and the Parathyroid Hormone in Postmenopausal Women in the Long-term after Roux-en-Y Gastric Bypass, Obesity Surgery, vol.84, issue.8, pp.1132-1140, 2009.
DOI : 10.1007/s11695-009-9890-y

J. Gomez, N. Vilarrasa, and C. Masdevall, Regulation of Bone Mineral Density in Morbidly Obese Women: A Cross-sectional Study in Two Cohorts Before and After Bypass Surgery, Obesity Surgery, vol.75, issue.3, pp.345-50, 2009.
DOI : 10.1079/PNS200194

J. Johnson, J. Maher, and I. Samuel, Effects of Gastric Bypass Procedures on Bone Mineral Density, Calcium, Parathyroid Hormone, and Vitamin D, Journal of Gastrointestinal Surgery, vol.9, issue.8, pp.1106-1117, 2005.
DOI : 10.1016/j.gassur.2005.07.012

P. Coates, J. Fernstrom, and M. Fernstrom, Gastric Bypass Surgery for Morbid Obesity Leads to an Increase in Bone Turnover and a Decrease in Bone Mass, The Journal of Clinical Endocrinology & Metabolism, vol.89, issue.3, pp.1061-1066, 2004.
DOI : 10.1210/jc.2003-031756

J. Fleischer, E. Stein, and M. Bessler, The Decline in Hip Bone Density after Gastric Bypass Surgery Is Associated with Extent of Weight Loss, The Journal of Clinical Endocrinology & Metabolism, vol.93, issue.10, pp.3735-3775, 2008.
DOI : 10.1210/jc.2008-0481

T. Mahdy, S. Atia, and M. Farid, Effect of Roux-en Y Gastric Bypass on Bone Metabolism in Patients with Morbid Obesity: Mansoura Experiences, Obesity Surgery, vol.20, issue.suppl, pp.1526-1557, 2008.
DOI : 10.12659/MSM.430365

F. Carrasco, M. Ruz, and P. Rojas, Changes in Bone Mineral Density, Body Composition and Adiponectin Levels in Morbidly Obese Patients after Bariatric Surgery, Obesity Surgery, vol.243, issue.1, pp.41-47, 2009.
DOI : 10.1002/j.1550-8528.1999.tb00404.x

N. Vilarrasa, J. Gomez, and I. Elio, Evaluation of Bone Disease in Morbidly Obese Women After Gastric Bypass and Risk Factors Implicated in Bone Loss, Obesity Surgery, vol.12, issue.7, pp.860-866, 2009.
DOI : 10.1007/s11695-009-9843-5

D. Casagrande, G. Repetto, and C. Mottin, Changes in Bone Mineral Density in Women Following 1-Year Gastric Bypass Surgery, Obesity Surgery, vol.19, issue.10, pp.1287-92, 2012.
DOI : 10.1007/s11695-009-9927-2

E. Stein, A. Carrelli, and P. Young, Bariatric Surgery Results in Cortical Bone Loss, The Journal of Clinical Endocrinology & Metabolism, vol.98, issue.2, pp.541-550, 2013.
DOI : 10.1210/jc.2012-2394

V. Mach, M. Stoeckli, R. Bilz, and S. , Changes in bone mineral content after surgical treatment of morbid obesity, Metabolism, vol.53, issue.7, pp.918-939, 2004.
DOI : 10.1016/j.metabol.2004.01.015

C. Riedt, R. Brolin, and R. Sherrell, True Fractional Calcium Absorption is Decreased After Roux-En-Y Gastric Bypass Surgery*, Obesity, vol.12, issue.11, pp.1940-1948, 2006.
DOI : 10.1152/japplphysiol.00264.2003

URL : http://onlinelibrary.wiley.com/doi/10.1038/oby.2006.226/pdf

C. Bruno, A. Fulford, and J. Potts, Serum Markers of Bone Turnover Are Increased at Six and 18 Months after Roux-En-Y Bariatric Surgery: Correlation with the Reduction in Leptin, The Journal of Clinical Endocrinology & Metabolism, vol.95, issue.1, pp.159-66, 2010.
DOI : 10.1210/jc.2009-0265

A. Carlin, D. Rao, and K. Yager, Treatment of vitamin D depletion after Roux-en-Y gastric bypass: a randomized prospective clinical trial, Surgery for Obesity and Related Diseases, vol.5, issue.4, pp.444-453, 2009.
DOI : 10.1016/j.soard.2008.08.004

M. Coupaye, M. Breuil, and P. Rivière, Serum Vitamin D Increases with Weight Loss in Obese Subjects 6??Months After Roux-en-Y Gastric Bypass, Obesity Surgery, vol.95, issue.4, pp.486-93, 2013.
DOI : 10.1210/jc.2009-0265

A. Carlin, D. Rao, and K. Yager, Effect of gastric bypass surgery on vitamin D nutritional status, Surgery for Obesity and Related Diseases, vol.2, issue.6, pp.638-680, 2006.
DOI : 10.1016/j.soard.2006.09.003

J. Jin, A. Robinson, and P. Hallowell, Increases in parathyroid hormone (PTH) after gastric bypass surgery appear to be of a secondary nature, Surgery, vol.142, issue.6, pp.914-934, 2007.
DOI : 10.1016/j.surg.2007.09.023

M. Nelson, L. Bolduc, and M. Toder, Correction of preoperative vitamin D deficiency after Roux-en-Y gastric bypass surgery, Surgery for Obesity and Related Diseases, vol.3, issue.4, pp.434-441, 2007.
DOI : 10.1016/j.soard.2007.02.007

J. Jin, T. Stellato, and P. Hallowell, Utilization of Preoperative Patient Factors to Predict Postoperative Vitamin D Deficiency for Patients Undergoing Gastric Bypass, Journal of Gastrointestinal Surgery, vol.142, issue.6, pp.1052-1059, 2009.
DOI : 10.1007/s11605-009-0847-1

E. Aasheim, S. Björkman, and T. Søvik, Vitamin status after bariatric surgery: a randomized study of gastric bypass and duodenal switch, The American Journal of Clinical Nutrition, vol.353, issue.1, pp.15-22, 2009.
DOI : 10.1080/1102680410003794

C. Signori, K. Zalesin, and B. Franklin, Effect of Gastric Bypass on Vitamin D and Secondary Hyperparathyroidism, Obesity Surgery, vol.12, issue.1, pp.949-52, 2010.
DOI : 10.1111/j.1365-2265.2006.02502.x

L. Flores, M. Osaba, M. Andreu, and A. , Calcium and Vitamin D Supplementation after Gastric Bypass Should Be Individualized to Improve or Avoid Hyperparathyroidism, Obesity Surgery, vol.18, issue.6, pp.738-781, 2010.
DOI : 10.4158/EP.14.3.318

P. Pramyothin, R. Biancuzzo, and Z. Lu, Vitamin D in Adipose Tissue and Serum 25-Hydroxyvitamin D After Roux-en-Y Gastric Bypass, Obesity, vol.43, issue.11, pp.2228-2262, 2011.
DOI : 10.1038/oby.2007.23

L. Beckman, C. Earthman, and W. Thomas, Serum 25(OH) Vitamin D Concentration Changes After Roux-en-Y Gastric Bypass Surgery, Obesity, vol.20, issue.12, pp.1-8, 2013.
DOI : 10.1038/oby.2011.404

URL : http://onlinelibrary.wiley.com/doi/10.1002/oby.20464/pdf

D. Avgerinos, M. Leitman, and R. Martinez, Evaluation of Markers for Calcium Homeostasis in a Population of Obese Adults Undergoing Gastric Bypass Operations, Journal of the American College of Surgeons, vol.205, issue.2, pp.294-301, 2007.
DOI : 10.1016/j.jamcollsurg.2007.02.078

M. Digiorgi, A. Daud, and W. Inabnet, Markers of Bone and Calcium Metabolism Following Gastric Bypass and Laparoscopic Adjustable Gastric Banding, Obesity Surgery, vol.29, issue.3, pp.1144-1152, 2008.
DOI : 10.1007/s11695-007-9408-4

W. Goldner, J. Stoner, and E. Lyden, Finding the Optimal Dose of Vitamin D Following Roux-en-Y Gastric Bypass: A Prospective, Randomized Pilot Clinical Trial, Obesity Surgery, vol.12, issue.6, pp.173-182, 2009.
DOI : 10.4158/EP.10.3.195

E. Lin, D. Armstrong-moore, and Z. Liang, Contribution of Adipose Tissue to Plasma 25-Hydroxyvitamin D Concentrations During Weight Loss Following Gastric Bypass Surgery, Obesity, vol.86, issue.3, pp.588-94, 2011.
DOI : 10.1007/s11695-008-9698-1

J. Sanchez-hernandez, J. Ybarra, and I. Gich, Effects of Bariatric Surgery on Vitamin D Status and Secondary Hyperparathyroidism: A Prospective Study, Obesity Surgery, vol.15, issue.10, pp.1389-95, 2005.
DOI : 10.1381/096089205774859182

J. Ybarra, J. Sanchez-hernandez, and I. Gich, Unchanged Hypovitaminosis D and Secondary Hyperparathyroidism in Morbid Obesity after Bariatric Surgery, Obesity Surgery, vol.15, issue.3, pp.330-335, 2005.
DOI : 10.1381/0960892053576758

D. Mdf, M. Diniz, and S. Sanches, Elevated serum parathormone after Rouxen-Y gastric bypass, Obes Surg, vol.14, pp.1222-1228, 2004.

Y. Youssef, W. Richards, and N. Sekhar, Risk of secondary hyperparathyroidism after laparoscopic gastric bypass surgery in obese women, Surgical Endoscopy, vol.15, issue.8, pp.1393-1399, 2007.
DOI : 10.1016/S0025-7125(16)30696-4

E. Fish, G. Beverstein, and D. Olson, Vitamin D Status of Morbidly Obese Bariatric Surgery Patients, Journal of Surgical Research, vol.164, issue.2, pp.198-202, 2010.
DOI : 10.1016/j.jss.2010.06.029

H. Bischoff-ferrari, E. Giovannucci, and W. Willett, Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes, The American Journal of Clinical Nutrition, vol.61, issue.4, pp.18-28, 2006.
DOI : 10.1093/ajcn/61.3.638S

E. Grethen, R. Mcclintock, and C. Gupta, Vitamin D and Hyperparathyroidism in Obesity, The Journal of Clinical Endocrinology & Metabolism, vol.96, issue.5, pp.1320-1326, 2011.
DOI : 10.1210/jc.2010-2202

S. Parikh, M. Edelman, and G. Uwaifo, The Relationship between Obesity and Serum 1,25-Dihydroxy Vitamin D Concentrations in Healthy Adults, The Journal of Clinical Endocrinology & Metabolism, vol.89, issue.3, pp.1196-1205, 2004.
DOI : 10.1210/jc.2003-031398

J. Wortsman, L. Matsuoka, and T. Chen, Decreased bioavailability of vitamin D in obesity, The American Journal of Clinical Nutrition, vol.58, issue.3, pp.690-693, 2000.
DOI : 10.1093/ajcn/58.6.882

E. Aarts, L. Van-groningen, and R. Horst, Vitamin D absorption: consequences of gastric bypass surgery, European Journal of Endocrinology, vol.87, issue.6, pp.827-859, 2011.
DOI : 10.1007/BF01311670

M. Holick, R. Biancuzzo, and T. Chen, in Maintaining Circulating Concentrations of 25-Hydroxyvitamin D, The Journal of Clinical Endocrinology & Metabolism, vol.93, issue.3, pp.677-81, 2008.
DOI : 10.1210/jc.2007-2308

J. Johnson, J. Maher, and E. Denaria, The Long-term Effects of Gastric Bypass on Vitamin D Metabolism, Annals of Surgery, vol.243, issue.5, pp.701-706, 2006.
DOI : 10.1097/01.sla.0000216773.47825.c1

P. Tondapu, D. Provost, and B. Adams-huet, Comparison of the Absorption of Calcium Carbonate and Calcium Citrate after Roux-en-Y Gastric Bypass, Obesity Surgery, vol.15, issue.3, pp.1256-61, 2009.
DOI : 10.1038/oby.2006.226

J. Mechanick, R. Kushner, and H. Sugerman, The Obesity Society, and American Society for Metabolic and Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient, American Association of Clinical Endocrinologists Obesity (Silver Spring), vol.17, issue.1, pp.1-70, 2009.

O. Ziegler, M. Sirveaux, and L. Brunaud, Medical follow up after bariatric surgery: nutritional and drug issues General recommendations for the prevention and treatment of nutritional deficiencies, Diabetes & Metabolism, vol.35, issue.6, pp.544-57, 2009.
DOI : 10.1016/S1262-3636(09)73464-0

. Vilarrasa, 2 36 1200 mg/d and 800 IU/d Femoral neck : -10.2±5.7%, (p<0.05) Lumbar spine : -3, 2±4.4%, (p<0.05) After 36 months : Femoral neck : -2.7±5.9% in comparison with 12 monthsp<0.05) Lumbar spine : -3.1±4.2% in comparison with 12 months, pp.2011-2027