Vitamin D in the Preoperative and Postoperative Periods of Bariatric Surgery

To evaluate the evolution of vitamin D levels (25OHD) in patients submitted to bariatric surgery.

Retrospective study, conducted with patients submitted to bariatric surgery between 2013 and 2018, in a city in the Northeast of Brazil. The variations of 25OHD, weight, body mass index (BMI), and total lymphocyte count were analyzed and compared for preoperative and postoperative periods of 6 and 12 months. Vitamin D levels below 30ng/mL were considered insufficient. Analysis of variance (ANOVA) was used for repeated measures, followed by Bonferroni post hoc test. To identify variables related to vitamin D, Pearson's correlation test and linear regression analysis were used. A significance level of 5% (p <0.05) was adopted.

A total of 646 patients were evaluated, with a mean age of 41.3 ± 10.8 years. Most of the patients were female (75%) and had 25OHD insufficiency in the preoperative period (79.1%). It was found that in the postoperative period there was an increase in vitamin D levels. Linear regression showed that the variation in vitamin D is negatively influenced by BMI in the preoperative period (β = -0.20; p = 0.02) and by BMI (β = -0.38; p <0.001) and by age (β = -0.08; p = 0.02) in the 6-month postoperative period.

There was an increase in vitamin D levels in the postoperative period. BMI proved to be a negative factor for obtaining adequate levels of vitamin D in the preoperative period and in the 6-month postoperative period.