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

Abstract

Purpose Secondary hyperparathyroidism (SHPT) after obesity surgery may affect bone health. Optimal vitamin D levels have not been established to prevent SHPT postoperatively. We investigated whether SHPT differed across threshold levels of serum 25-hydroxyvitamin D (S-25(OH)D) from 6 months up to 5 years after Roux-en-Y gastric bypass (RYGB). Materials and Methods We included 554 patients at follow-up 5 years postoperatively. Blood samples were analysed for S-25(OH)D, ionized calcium (iCa) and parathyroid hormone (PTH) during follow-up. Results PTH and prevalence of SHPT increased from 6 months to 5 years postoperatively, while S-25(OH)D and iCa decreased (all P < 0.001). PTH and SHPT development are related with S-25(OH)D, and PTH differed between all subgroups of S-25(OH)D. SHPT occurred less frequently across all subgroups of S-25(OH)D ≥ 50 nmol/l during follow-up: odds ratio (OR) 0.44 (95% CI 0.36-0.54) in patients with S-25(OH)D ≥ 50 nmol/l, OR 0.38 (0.30-0.49) with S-25(OH)D ≥ 75 nmol/l and OR 0.19 (0.12-0.31) with S-25(OH) D ≥ 100 nmol/l, all compared with S-25(OH)D < 50 nmol/l. At 5 years, 208/554 patients (38%) had SHPT; SHPT was found in 94/188 patients (50%) with S-25(OH)D < 50 nmol/l, in 69/222 (31%) with S-25(OH)D 50-74 nmol/l, in 40/117 (34%) with S-25(OH)D 75-99 nmol/l and in 5/27 (19%) with S-25(OH)D ≥ 100 nmol/l. An interaction existed between S-25(OH)D and iCa. Bone alkaline phosphatase remained increased with SHPT. Conclusions A significant relationship existed between S-25(OH)D and development of PTH and SHPT. The prevalence of SHPT was lower with threshold levels 25(OH)D ≥ 50 nmol/l and ≥ 75 nmol/l over the 5 years, and lowest with S-25(OH)D ≥ 100 nmol/l.

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.…”

“…The study quality assessment is also displayed in this table. Of all included studies, 30 were considered inadequate for vitamin D and calcium supplementation, [7][8][9][10]14,16,17,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] and 4 were assessed as adequate supplementation 4,5,11,15 (Table 2). Of the 30 studies with inadequate supplementation, 6 reported data for ≤1 year of follow-up, 19 for >1 and ≤5 years, 3 for >5 and ≤10 years, and 2 for >10 years.…”

Bone Response to Weight Loss Following Bariatric Surgery

“…Among these, calcium is absorbed passively as well as actively in the small intestine, and a study using a dual stable calcium isotope method ( 198 ) demonstrated a significant reduction in calcium absorption following RYGB despite adequate vitamin D and calcium intake. With concern to vitamin D, even solely restrictive procedures like SG can lead to postoperative vitamin D deficiency in as much as 39% of patients despite daily multivitamin supplementation ( 199 ), while malabsorptive surgeries pose a higher risk for nutrient deficiencies ( 200 ). In a retrospective study, a 73% incidence of vitamin D deficiency was observed following BPD ( 201 ).…”

“…despite adequate vitamin D and calcium intake. With concern to vitamin D, even solely restrictive procedures like SG can lead to postoperative vitamin D deficiency in as much as 39% of patients despite daily multivitamin supplementation (199), while malabsorptive surgeries pose a higher risk for nutrient deficiencies (200). In a retrospective study, a 73% incidence of vitamin D deficiency was observed following BPD (201).…”

Metabolic surgery in treatment of obese Japanese patients with type 2 diabetes: a joint consensus statement from the Japanese Society for Treatment of Obesity, the Japan Diabetes Society, and the Japan Society for the Study of Obesity

“…As the risk of cholelithiasis increases after metabolic surgery [ 219 ], regularly examination by abdominal ultrasonography would be preferred. Furthermore, since bone mass may reduce due to secondary hyperparathyroidism associated with vitamin D and calcium deficiency after metabolic surgery [ 220 , 221 ], bone mineral density evaluation would be preferred every 2 years.…”