Vitamin D Deficiency and Paratohommonium Increase in Late Postoperative Gastric Bypass in Roux-en-Y

Abstract

Background : Roux-en-Y gastric bypass patients can experience changes in calcium metabolism and hyperparathyroidism secondary to vitamin D deficiency. Aim : To evaluate nutritional deficiencies related to the calcium metabolism of patients undergoing gastric bypass with a 10-year follow-up. Method : This is a longitudinal retrospective study of patients submitted to Roux-en-Y gastric bypass at a multidisciplinary clinic located in the Brazilian southeast region. The study investigated the results of the following biochemical tests: serum calcium, ionized calcium, vitamin D, and parathormone (PTH). The generalized estimating equations (GEE) determined the nutritional deficiencies using a significance level of 5%. Results : Among the patients who finished the study (120 months), 82.86% (n=29) had vitamin D deficiency, and 41.94% (n=13) had high PTH. Postoperative time had a significant effect on PTH (p=0.0059). The percentages of patients with vitamin D, serum calcium, and ionized calcium deficiencies did not change significantly over time. Conclusion : One of the outcomes was vitamin D deficiency associated with secondary hyperparathyroidism. These findings reaffirm the importance of monitoring the bone metabolism of patients submitted to Roux-en-Y gastric bypass. HEADINGS:Calcium deficiency. Vitamin D deficiency. Secondary hyperparathyroidism.

Relationships Between Vitamin D Status and PTH over 5 Years After Roux-en-Y Gastric Bypass: a Longitudinal Cohort Study

“…The observed increase in PTH from 6 months is in accordance with other long-term evaluations [9][10][11][12][13]. S-25(OH)D was strongly related with PTH over time, however, with limited differences in SHPT by traditional target thresholds,…”

“…Calcium and vitamin D are central in parathyroid hormone (PTH) regulation [7,8]. Frequently, PTH is elevated after obesity surgery, and long-term studies indicate that PTH increases over time [4,[9][10][11][12][13][14][15].…”

Metabolic bone changes after bariatric surgery: 2020 update, American Society for Metabolic and Bariatric Surgery Clinical Issues Committee position statement

“…Although these hormonal changes are thought to impart many of the positive metabolic benefits of bariatric surgery, they may also contribute to bone loss. Hence, it remains essential to monitor levels of calcium, vitamin D, and parathyroid hormone both before and in the long term after bariatric surgery [18][19][20][21][22].…”

“…This has been attributed to decreased dietary calcium intake; decreased absorption due to bypassing the proximal bowel, where calcium is preferentially absorbed; decreased absorption secondary to reduced gastric acid; malabsorption of vitamin D; and decreased mechanical loading on bones [1,26,27]. As mentioned, patients with obesity have a high prevalence of vitamin D deficiency at baseline (60%-80%), and the prevalence may not change over time [22]. In addition, rates of secondary hyperparathyroidism are high in post-RYGB patients (23.7%-42%), although lower than in post-BPD-DS patients (72.5%).…”

Prevalence and associated factors of secondary hyperparathyroidism after Roux‐en‐Y gastric bypass: A meta‐analysis

“…After the exclusion of ineligible studies, our final sample was 30 studies. 4,5,[7][8][9][10][11][14][15][16][17][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] Among them, four studies had two arms, these arms were analyzed separately in this meta-analysis 14,31,34,39 (Figure 1). The characteristics of included studies are presented in Table 1.…”