Purpose: In Brazil and worldwide, few studies have investigated vitamin D deficiency in patients with severe obesity who underwent bariatric surgery associated with latitude and level of solar radiation. The objective of this study was to investigate the prevalence of vitamin D deficiency and the predictive factors of serum level changes after 12 months of RYGB in a low latitude region.
Materials and methods: This study included 50 patients from a low-latitude city (10° 10' 8″ S) in the north of Brazil. We collected data before surgery and after 3 and 12 months of surgery. The level of vitamin D was classified as deficiency (< 20 ng/ml), insufficiency (20-30 ng/ml), and sufficiency (≥ 30 ng/ml).
Results: The mean age of the patients was 38.7 ± 8.9 years, 69% were women, and percent excess weight loss (% EWL) was 83% after 1 year of surgery. The prevalence of vitamin D deficiency in the preoperative period was 14%, and after 3 and 12 months of surgery, it decreased to 4% and 6%, respectively. The variation in vitamin D after 12 months of surgery was positively associated with changes in BMI, body fat, and % EWL.
Conclusions: The prevalence of vitamin D deficiency is low in patients undergoing bariatric surgery in the northern region of Brazil, which is possibly related to low latitude. Weight loss was positively associated with an increase in serum vitamin D after surgery.
Keywords: Bariatric surgery; Brazil; Latitude and weight loss; Vitamin D.