PTH and vitamin D deficiency: Previous studies reported that patients who underwent sleeve gastrectomy had maintained their serum calcium and phosphorus levels with strict vitamin D supplementation (Jaruvongvanich et al., 2019; Misra et al., 2020) and that bariatric surgery was associated with hyperparathyroidism, vitamin D deficiency, and lower calcium levels (Altawil et al., 2021), indicating the need to perform routine testing for parathyroid hormone and vitamin D. Our study demonstrated no significant changes in serum calcium and phosphorus levels without calcium or vitamin D supplementation.