Vitamin D Status 10 Years After Primary Gastric Bypass: Gravely High Prevalence of Hypovitaminosis D and Raised PTH Levels.
Obes Surg. 2013 Oct 28.
Karefylakis C, Näslund I, Edholm D, Sundbom M, Karlsson FA, Rask E.
Division of Internal Medicine, Department of Endocrinology, Örebro University Hospital, SE-70185, Örebro, Sweden, christos.karefylakis at orebroll.se.
BACKGROUND: The primary aim of this study was to evaluate the prevalence of vitamin D deficiency and secondary hyperparathyroidism after Roux-en-Y gastric bypass. Secondly, we have tried to assess predictors for vitamin D deficiency.
METHODS: Five hundred thirty-seven patients who underwent primary Roux-en-Y gastric bypass surgery between 1993 and 2003 at the Örebro University Hospital and Uppsala University Hospital were eligible for the study. Patients were asked to provide a blood sample between November 2009 and June 2010 and to complete a questionnaire about their postoperative health status. Serum values of 25-OH vitamin D, parathyroid hormone (PTH), alkaline phosphatase (ALP) and calcium were determined.
RESULTS: Follow-up was completed in 293 patients, of which 83 % were female, with an age of 49 ± 9.9 years after a median time of 11 ± 2.8 years. Vitamin D, PTH and albumin-corrected calcium values were 42 ± 20.4 nmol/L, 89.1 ± 52.7 ng/L and 2.3 ± 0.1 mmol/L, respectively. Of all patients, 65 % were vitamin D deficient, i.e. 25-OH vitamin D <50 nmol/L, and 69 % had PTH above the upper normal reference range, i.e. >73 ng/L. Vitamin D was inversely correlated with PTH levels (p < 0.001) and positively correlated with calcium (p = 0.016). Vitamin D did not correlate with ALP. The only factor found to predict vitamin D deficiency was high preoperative body mass index (BMI) (p = 0.008), whereas gender, age, time after surgery and BMI at follow-up did not.
CONCLUSIONS: Vitamin D deficiency and secondary hyperparathyroidism after Roux-en-Y gastric bypass (RYGB) were confirmed in our study because 65 % of patients had vitamin D deficiency, and 69 % had increased PTH levels more than 10 years after surgery. These data are alarming and highlight the need for improved long-term follow-up. Vitamin D deficiency does not seem to progress with time after surgery, possibly due to weight loss. Only preoperative BMI, cutoff point 43 kg/m2, was a predictor of vitamin D deficiency at follow-up. Improved long-term follow-up of patients that undergo RYGB is needed.
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