SAN DIEGO — Several preoperative factors—a longer bypass limb length, low vitamin D levels, and African American ethnicity—were significant predictors of postoperative vitamin D deficiency in a study of 145 patients undergoing gastric bypass surgery.
Vitamin D deficiency can place such patients at increased risk for calcium and parathyroid hormone (PTH) abnormalities, and identifying the deficiency prior to surgery allows clinicians to intervene, Dr. Judy Jin wrote in a poster presented at the annual Digestive Disease Week.
Dr. Jin, of the department of surgery at Case Western Reserve University in Cleveland, and her colleagues reviewed data from 145 patients who underwent Roux-en-Y gastric bypass surgery between January 2005 and October 2006. The average age of the patients was 44 years, and the average BMI was 49 kg/m
The researchers tracked patient demographics and the laboratory values of calcium, vitamin D, and parathyroid hormone at 3-month intervals for 1 year. Overall, 42% of the patients had vitamin D deficiency (defined as vitamin D levels less than 20 ng/mL) either before surgery or during the 1-year follow-up period.
In a multivariate analysis, patients with postoperative vitamin D deficiency had significantly lower preoperative vitamin D levels than did those who didn't have postoperative deficiency (19.9 ng/mL vs. 30.0 ng/mL). Patients with postoperative vitamin D deficiency also were significantly more likely to have had a longer limb bypass (165 cm) vs. a short limb bypass (75 cm) and to be African American vs. another ethnicity. Preoperative PTH levels, age, sex, or reduction in BMI had no apparent effect on postoperative vitamin D.
Dr. Jin reported that she had no conflicts to disclose.