腹腔镜胃旁路术后病态肥胖症患者微量营养素缺乏的诊治

目的 探讨行腹腔镜胃旁路术后病态肥胖症患者血清微量营养素的变化. 方法回顾性分析121例病态肥胖症患者腹腔镜胃旁路术后6、12、24个月血清铁(Fe)、钙(Ca)、锌(Zn)、硒(Se)及维生素A(VitA)、维生素D(VitD)、维生素B12(VitB12)和甲状旁腺素(PTH)水平的变化.结果 本组121例病态肥胖症患者术前1个月平均体质量指数(body mass index,BMI)为(47±7)kg/m2,术后6个月平均BMI为(34±6)kg/m2,术后BMI平均下降(13±5)kg/m2(P＜0.01).在术后的2年随访中,血清Fe、Ca、Zn、Se、VitA、VitD、VitB12均在正常范围.虽然一些患者的血清Zn、Se和VitA水平偏低,但接近正常.而血清PTH始终高于正常水平,术后6、12、24个月分别升高了(22±34)pg/ml、(28±34)pg/ml、(31±40)pg/ml(P＜0.05).结论 本研究证明腹腔镜胃旁路手术治疗病态肥胖症患者是有效、安全的,但术后患者血清Ca、Zn、Se代谢及PTH水平有所改变.因此,建议所有腹腔镜胃旁路手术患者术后长期服用多种维生素和矿物质补充剂.     

Vitamin D metabolite requirements in dialysed children receiving recombinant human growth hormone.

BACKGROUND: The aim of the study was to assess the requirement of active vitamin D in dialysed children during treatment with recombinant human growth hormone (rhGH). METHODS: Twenty-six children (aged 5-15 years) were treated with rhGH for 6 months. The serum concentration of parathyroid hormone (PTH), alkaline phosphatase (AP), and calcium and phosphorus were measured in two groups of patients studied in the years 1994-1995 (group I) and 1995-1998 (group II) respectively. Group I received a constant dose of alfacalcidol that was sufficient to keep PTH below 200 pg/ml before rhGH treatment began. The serum PTH level was checked every 3 months. Alfacalcidol was administered to group II according to serum PTH levels checked on a monthly basis. RESULTS: In group I the PTH level increased after 3 and 6 months of rhGH treatment from mean level 73+/-60; 155+/-156 and 344+/-249 pg/ml respectively; P<0.05. AP activity increased after 6 months of treatment from 206+/-99 to 325+/-124 U/l respectively; P<0.01. The calcium level decreased from baseline after 3 months of treatment from 2.36+/-0.21 to 2.17+/-0.12 mmol/l respectively; P<0.05. In group II AP activity increased after 3 and 6 months of treatment from 272+/-169 to 332+/-192 and 404. 9+/-219.8 U/l respectively; P<0.01. The mean level of phosphorus decreased after 6 months from 2.15+/-0.28 to 1.70+/-0.39 mmol/l respectively; P<0.01. In group II the mean dose of alfacalcidol increased by 60.9%. CONCLUSIONS: In children with end-stage renal failure, higher doses of vitamin D are needed during rhGH treatment. During rhGH treatment, frequent control of serum PTH level is necessary.     

Micronutrient Deficiencies After Laparoscopic Gastric Bypass: Recommendations

Background  The aim of this study was to evaluate the changes of micronutrients in patients with morbid obesity after laparoscopic Roux-en-Y gastric bypass surgery (LRYGBP). Methods  We retrospectively reviewed 121 patients diagnosed with morbid obesity who undertook LRYGBP and evaluated the serum iron (Fe), calcium (Ca), zinc (Zn), selenium (Se), vitamin A (VitA), 25-hydroxy vitamin D3 (VitD), vitamin B₁₂ (VitB₁₂), and parathormone (PTH) measured at 6, 12, and 24 months after LRYGBP. Results  During a follow-up period of 69 months (June 1999 to February 2005), a cohort of 121 patients, 40 men and 81 women, underwent LRYGBP, a mean age of 46 years (range 22–67). The mean body mass index (BMI) before LRYGBP was 47.00 ± 7.15 kg/m² (range 30.65–76.60 kg/m²). After 6 months of the surgery, the mean BMI was 33.79 ± 6.06 kg/m² (range 21.70–52.76 kg/m²). The mean BMI decreased (P < 0.001) 6 months after the surgery. Within the following 2 years, the serum Fe, Ca, Zn, Se, VitA, VitD, and VitB₁₂ had normalized. The serum Zn, Se, and VitA of some patients decreased but were nearly normal. In contrast, serum PTH remained continuously at a higher level than normal. Conclusions  This study confirms that LRYGBP is a reliable and safe weight loss method for the patients suffering from morbid obesity. After surgery, serum Ca, Zn, and Se metabolisms and PTH levels are altered in these patients. Therefore, multi-vitamin and mineral supplementation are strongly recommended in all patients after LRYGBP.     

The effect of a short course of calcium and vitamin d on bone turnover in older women

Calcium and vitamin D (1200 mg/day + 800 IU) has been shown to reduce hip fracture incidence in older women living in long-term care facilities who had borderline low vitamin D levels. We examined the effect of a short course of calcium and vitamin D on biochemical markers of bone turnover in older community-living women. Twelve community-living women (mean age 75 years) in good general health, without diseases or on medications known to affect bone, were entered into the study. All women were treated with calcium citrate (1500 mg/day of elemental calcium) and vitamin D₃ (1000 IU/day) (Ca + D) for 6 weeks. Biochemical markers of bone turnover were measured in serum and urine collected at baseline (two samples), 5 and 6 weeks on Ca + D, and 5 and 6 weeks after termination of Ca + D. Markers of bone formation were osteocalcin, bone alkaline phosphatase and type I procollagen peptide. Markers of bone resorption were urinary hydroxyproline, free pyridinoline and deoxypyridinoline crosslinks, and N-telopeptides of type I collagen. Parathyroid hormone (PTH) and 25-hydroxyvitamin D were also measured at baseline, 6 weeks on treatment and 6 weeks after termination of treatment. All markers of bone resorption decreased on Ca + D and returned to baseline after termination of Ca + D (p<0.05). Markers of bone formation did not change with Ca + D treatment. PTH decreased on Ca + D and returned to baseline after treatment, and 25-hydroxyvitamin D increased with treatment and remained elevated 6 weeks after the end of treatment. We conclude that Ca + D reduces bone resorption in older women, possibly by suppressing PTH levels.     

Short-term changes in bone and mineral metabolism following gastrectomy in gastric cancer patients

Changes in bone and mineral metabolism that occur after gastrectomy have long been recognized. Gastrectomy has been identified as a risk factor for decreased bone mass and the increased fracture incidence. Previous investigations concerning postgastrectomy bone disease have been observational studies. No prospective studies have been reported that quantify the amount of bone loss after gastrectomy within the same patients. This study investigated 46 patients undergoing gastrectomy for gastric adenocarcinoma and analyzed 36 patients (58.1+/-10.8 years, 24 men and 12 women) who had dual energy X-ray absorptiometry (DXA) performed before and 1 year after gastrectomy. Systemic adjuvant chemotherapy was administered to 14 patients. Blood was sampled from all patients to determine serum calcium, phosphorous, and bone turnover marker levels before gastrectomy and at 1, 3, 6 and 12 months after surgery and for serum parathyroid hormone (PTH) and 25-hydroxyvitamin D levels before and 12 months after surgery. The mean bone loss in the lumbar spine, total hip, femoral neck, and trochanter, which was calculated as the percentage change from the baseline to the level measured at 12 months, was 5.7% (P<0.01), 5.4% (P<0.01), 6.6% (P<0.01) and 8.7% (P<0.01), respectively. Bone loss was generally greater in the group receiving chemotherapy. The serum calcium and phosphorous levels were not changed significantly and remained within the normal range throughout the observation period. After gastrectomy, the level of ICTP increased and reached a peak at 1 and 3 months, and progressively declined to baseline by 12 months. The osteocalcin levels were not coupled to an increase before 6 months. The level of 25-hydroxyvitamin D at 12 months postgastrectomy was not significantly changed compared to the baseline, however, the PTH levels increased by a mean of 63.6% at 12 months compared to the baseline (P<0.01). Significant correlations were found between the percent change in the BMD at the lumbar spine and total hip and the percentage change for the PTH level from their baselines to 12 months. The changes in the BMD at total hip, femoral neck, and trochanter also correlated to the change in body weight at 12 months. The data obtained by this study provides evidence that profound bone loss occurs in the setting of a bone remodeling imbalance during the early postgastrectomy period and allows the speculation that the gastrectomy related bone loss may be partially due to an overproduction of PTH.     

Effect of a low calcium dialysate on parathyroid hormone secretion in diabetic patients on maintenance hemodialysis.

Diabetic patients on maintenance dialysis often are characterized by a relative parathyroid hormone (PTH) deficiency and a form of renal osteodystrophy with low bone turnover known as adynamic bone. The goal of the present study was to determine whether a reduction in the dialysate calcium concentration would increase the predialysis (basal) PTH and maximal PTH level. Thirty-three diabetic maintenance hemodialysis patients with basal PTH values less than 300 pg/ml were randomized to be dialyzed with either a regular (3.0 mEq/liter or 3.5 mEq/liter, group I) or low (2.25 mEq/liter or 2.5 mEq/liter, group II) calcium dialysate for 1 year. At baseline and after 6 months and 12 months of study, low (1 mEq/liter) and high (4 mEq/liter) calcium dialysis studies were performed to determine parathyroid function. At baseline, basal (I, 126+/-20 vs. II, 108+/-19 pg/ml) and maximal (I, 269 pg/ml+/-40 pg/ml vs. II, 342 pg/ml+/-65 pg/ml) PTH levels were not different. By 6 months, basal (I, 98+/-18 vs. II, 200+/-34 pg/ml, p = 0.02) and maximal (I, 276 pg/ml+/-37 pg/ml vs. II, 529 pg/ml+/-115 pg/ml; p = 0.05) PTH levels were greater in group II. Repeated measures analysis of variance (ANOVA) of the 20 patients who completed the entire 12-month study showed that only in group II patients were basal PTH (p = 0.01), maximal PTH (p = 0.01), and the basal/maximal PTH ratio (p = 0.03) different; by post hoc test, each was greater (p < 0.05) at 6 months and 12 months than at baseline. When study values at 0, 6, and 12 months in all patients were combined, an inverse correlation was present between basal calcium and both the basal/maximal PTH ratio (r = -0.59; p < 0.001) and the basal PTH (r = -0.60; p < 0.001). In conclusion, in diabetic hemodialysis patients with a relative PTH deficiency (1) the use of a low calcium dialysate increases basal and maximal PTH levels, (2) the increased secretory capacity (maximal PTH) during treatment with a low calcium dialysate suggests the possibility of enhanced parathyroid gland growth, and (3) the inverse correlation between basal calcium and both the basal/maximal PTH ratio and the basal PTH suggests that the steady-state PTH level is largely determined by the prevailing serum calcium concentration.     

Remission of hypercalciuria in patients with tuberculosis after treatment

The hypercalciuria evolution and other bone metabolism parameters were evaluated in patients with tuberculosis after treatment. Twenty-two patients with tuberculosis and 54 normal subjects were studied; they consumed an average diet (calcium intake 1000 mg/day). Ten of these patients and nine normal subjects were also studied after a low calcium diet (400 mg/calcium/day) and after a load of oral calcium of 1000 mg (calcium absorption test). The study with an average diet was performed after 1 week (basal) and 3, 6, and 12 months after the antituberculosis treatment was started; the calcium absorption test was carried out 2 weeks, 3 and 12 months after the treatment was started. On an average diet, patients with tuberculosis presented, at baseline state, lower calcidiol levels than normal controls. Serum calcitriol levels at baseline were higher than at 6 and 12 months. Serum parathyroid hormone (PTH) levels in patients with tuberculosis were lower than in normal controls at baseline, but these levels were similar to controls at 3, 6, and 12 months after treatment. During the calcium absorption test and under basal conditions, patients with tuberculosis showed lower serum PTH and calcidiol levels in all the dietetic situations than in normal controls. However, serum calcitriol levels were higher than in controls after the restrictive diet. After 3 months of treatment, urinary calcium excretion was normal in patients with tuberculosis during the average and low diets, but higher than in control group after calcium load. After 12 months of treatment, all the biochemical parameters of the patients with tuberculosis were similar to the control group under all the dietetic situations. These data indicate that antituberculous treatment, although it may contribute to the production of some alteration in the calcium and vitamin D metabolism, basically favors the correction of disturbances associated with tuberculosis.     

Vitamin D insufficiency defined by serum 25-hydroxyvitamin D and parathyroid hormone before and after oral vitamin D3 load in Japanese subjects

Vitamin D insufficiency is a risk for both skeletal and nonskeletal health. However, some ambiguity remains about threshold serum 25(OH)D for vitamin D insufficiency. To determine the threshold serum 25(OH)D to maintain normal calcium availability without elevation in serum parathyroid hormone (PTH) among Japanese subjects with various calcium intakes, we conducted a multicenter prospective open-labeled study. We recruited 107 ambulatory subjects without disorders affecting vitamin D metabolism to whom oral vitamin D₃ 800?IU/day for 4?weeks or 1,200?IU/day for 8?weeks was given. Serum 25(OH)D, PTH, calcium, phosphate, and magnesium were measured before and after vitamin D₃ supplementation. Calcium intake was assessed by questionnaires. When all the data were combined, serum 25(OH)D was negatively correlated with PTH. The cubic spline curve between serum 25(OH)D and PTH indicated PTH reached its plateau between 35 and 40?pg/ml at 25(OH)D between 25 and 30?ng/ml. Vitamin D₃ supplementation increased serum 25(OH)D and decreased PTH. Change in PTH correlated positively with baseline serum 25(OH)D. From the regression analyses, baseline serum 25(OH)D above 28?ng/ml corresponded to the threshold level without reduction in PTH after vitamin D₃ supplementation. In multivariate regression analyses, age but not calcium intake was a significant determinant of PTH. We concluded that a serum 25(OH)D level of 28?ng/ml was identified as a threshold for vitamin D insufficiency necessary to stabilize PTH to optimal levels.     

Vitamin D Supplementation in Young White and African American Women

There is limited information on the effects of vitamin D on serum 25 hydroxyvitamin D (25OHD) in young people and none on African Americans. The main objective of this trial was to measure the effect of different doses of vitamin D3 on serum 25OHD and serum parathyroid hormone (PTH) in young women with vitamin D insufficiency (serum 25OHD ≤ 20 ng/mL (50 nmol/L). A randomized double‐blind placebo‐controlled trial of vitamin D3 was conducted in young white and African American women, age 25 to 45 years. A total of 198 healthy white (60%) and African American (40%) women were randomly assigned to placebo, or to 400, 800, 1600, or 2400 IU of vitamin D3 daily. Calcium supplements were added to maintain a total calcium intake of 1000 to 1200 mg daily. The primary outcomes of the study were the final serum 25OHD and PTH levels at 12 months. The absolute increase in serum 25OHD with 400, 800, 1600, and 2400 IU of vitamin D daily was slightly greater in African American women than in white women. On the highest dose of 2400 IU/d, the mixed model predicted that mean 25OHD increased from baseline 12.4 ng/mL (95% confidence interval [CI], 9.2–15.7) to 43.2 ng/mL (95% CI, 38.2–48.1) in African American women and from 15.0 ng/mL (95% CI, 12.3–17.6) to 39.1 ng/mL (95% CI, 36.2–42.0) in white women. There was no significant effect of vitamin D dose on serum PTH in either race but there was a significant inverse relationship between final serum PTH and serum 25OHD. Serum 25OHD exceeded 20 ng/mL in 97.5% of whites on the 400 IU/d dose and between 800 and 1600 IU/d for African Americans. The recommended dietary allowance (RDA) suggested by the Institute of Medicine for young people is 600 IU daily. The increase in serum 25OHD after vitamin D supplementation was similar in young and old, and in white and African American women. © 2014 American Society for Bone and Mineral Research.     

Calcium supplements lower bone resorption after renal transplant

Yu RW, Faull RJ, Coates PTH, Coates PS. Calcium supplements lower bone resorption after renal transplant.
Clin Transplant 2011 DOI: 10.1111/j.1399‐0012.2011.01487.x.
© 2011 John Wiley & Sons A/S. Abstract: Aim: Bone loss in renal transplant (RT) patients is a problem that begins during end‐stage kidney disease and persists after transplantation. Suppression of parathyroid hormone (PTH) may decrease bone loss and improve fracture rate. Methods: A single‐group prospective intervention study involving 30 patients was performed at a large RT unit. Investigations included dual‐emission X‐ray absorptiometry scan, vertebral X‐ray, calcium absorption test, 24‐h urinary calcium and serum measurements of total and ionized calcium, PTH, C‐telopeptide cross‐links (CTX), osteocalcin, alkaline phosphatase, 25 hydroxyvitamin D (25[OH]D), and 1,25‐dihydroxyvitamin D3. Patients were given 500 mg elemental calcium daily for seven d, and serum measurements were repeated. Results: Two‐tailed Wilcoxon rank‐sum test showed significant decreases in PTH (p < 0.01) and CTX (p < 0.01) after calcium load. Dietary calcium, mean calcium absorption, and urinary calcium excretion were below desirable levels. Mean 25 hydroxyvitamin D (25(OH)D) was low, but levels of 1,25‐dihydroxyvitamin D3 were normal. Calcium absorption significantly correlated with change in PTH (p < 0.001), baseline 25(OH)D (p < 0.001), and mycophenolate dose (p = 0.024). Conclusions: Calcium malabsorption is prevalent in RT recipients, contributing to bone destruction and compounded by poor dietary intake and low 25(OH)D. Calcium supplementation appears to help overcome this deficiency and acutely suppress PTH. Calcium may be an effective and inexpensive therapy for bone loss in RT recipients.     

Vitamin D Does Not Increase Calcium Absorption in Young Women: A Randomized Clinical Trial

It is commonly said that vitamin D should be used to increase calcium absorption. We tested this statement in a dose‐response study of vitamin D on calcium absorption. A total of 198 white and African American women, aged 25 to 45 years, with vitamin D insufficiency, serum 25‐hydroxyvitamin D (25OHD) <20 ng/mL, were randomized in a double‐blind study to vitamin D3 400, 800, 1600, 2400 IU, or placebo. A calcium supplement was given to increase mean calcium intake at baseline from 706 mg/d to 1031 mg/d. Calcium absorption was measured at baseline and after 12 months using a single isotope method with radiocalcium45 and 100 mg of calcium. Mean baseline serum 25OHD was 13.4 ng/mL (33.5 nmol/L) and increased to 40 ng/mL (100 nmol/L) on the highest dose of 2400 IU. Using a multivariate regression analysis with significant predictors, baseline absorption, calcium intake, and weight, there was no increase in 12‐month calcium absorption compared with baseline on any dose of vitamin D in either whites or African Americans. There was no significant relationship between 12‐month calcium absorption and final serum 25OHD. In an analysis of calcium absorption and serum 25OHD at baseline, serum 25OHD levels were divided into groups: 0 to 5, 6 to 10, 11 to 15, or 16 to 20 ng/mL. There was no evidence of a threshold decrease in calcium absorption or serum 1,25 dihydroxyvitamin D (1,25(OH)₂D) amongst the lowest groups. Vitamin D doses up to 2400 IU daily did not increase calcium absorption. No threshold level of serum 25OHD for calcium absorption was found at baseline or in the longitudinal study, suggesting that active transport of calcium is saturated at very low serum 25OHD levels <5 ng/mL. There is no need to recommend vitamin D for increasing calcium absorption in normal subjects. Very efficient calcium absorption at very low levels of serum 25OHD explains why people do not develop osteomalacia provided that dietary intakes of calcium and phosphorus are adequate. © 2014 American Society for Bone and Mineral Research.     

Effects of Race on Diurnal Patterns of Renal Conservation of Calcium and Bone Resorption in Premenopausal Women

Previous studies showed differences in bone and mineral metabolism in African-Americans and Caucasians: reductions in serum 25-hydroxyvitamin D [25(OH)D], urinary calcium and skeletal remodeling and moderate secondary hyperparathyroidism. Diurnal studies were carried out in 7 African-American and 7 white normal premenopausal women matched for age, weight and height to further characterize these racial differences in calcium homeostasis. Serum 25(OH)D was significantly lower and serum intact parathyroid hormone (PTH) was significantly higher in the African-American compared with the white women, whereas serum total calcium, Ca²⁺, phosphorus and 1,25-dihydroxyvitamin D [1,25(OH)₂D] were not different in the two groups. Serum intact PTH increased significantly at night in the white women and did not change in the African-American women. Urinary calcium was 47% lower in the African-American than in the white women during the day but was not different at night. Urinary calcium declined at night by 53% in the white women and by 40% in the African-American women. Stepwise multivariate analysis showed that determinants of urinary calcium were mean 24 h serum intact PTH and serum Ca²⁺ in the two groups together, mean 24 h serum intact PTH, body mass index (BMI) and serum 25(OH)D in the white women, and BMI in the African-American women. Urinary N-telopeptide of type I collagen, a marker of bone resorption, increased by over 60% at night in both groups and was 25% lower in African-American compared with white women, but the difference was not statistically different. Urinary free deoxypyridinoline also increased at night in both groups and was not racially different. Thus, African-American women show higher serum intact PTH and greater conservation of calcium than white women throughout the day. In both groups, maintenance of serum calcium at night is achieved by increased bone resorption and renal conservation of calcium. Received: 15 April 1999 / Accepted: 6 July 1999     

Race is a major determinant of secondary hyperparathyroidism in uremic patients: comparative study of Blacks and Hispanics

BACKGROUND: Racial differences in bone and mineral metabolism are characterized by higher circulating intact parathyroid hormone levels (iPTH) in Black vs. White patients with end-stage renal disease (ESRD). The susceptibility of Hispanic patients to secondary hyperparathyroidism is not known. METHOD: This is a cross-sectional study that compares bone and mineral parameters of 48 Black and 61 Hispanic ESRD patients attending a single outpatient hemodialysis center. RESULT: The mean iPTH level was significantly higher in Blacks vs. Hispanics, despite similar levels of serum bone-specific alkaline phosphatase (BSAP), calcium, phosphorus and similar dosages of vitamin D analogs. After adjusting for independent variables including age, diabetic status and plasma levels of C-reactive protein, phosphorus and albumin significant predictors of iPTH were race (p < 0.01), gender (p < 0.05), serum calcium (p < 0.05), BSAP (p < 0.0001) and doses of vitamin D analogs (p < 0.001). Adjusted predictors of serum BSAP were PTH (p < 0.0001), gender (p = 0.01) and serum albumin (p < 0.005), but not race. There was no significant difference in serum BSAP between Blacks and Hispanics despite 60% higher iPTH levels in Blacks. CONCLUSIONS: Amongst ESRD patients, Blacks have higher iPTH levels compared with Hispanics despite similar BSAP levels, these finding support the emerging evidence of racial/ethnic differences in response of bone to PTH action.     

Acute Effects of Calcitonin Nasal Spray on Serum C-telopeptide of Type 1 Collagen (CTx) Levels in Elderly Osteopenic Women with Increased Bone Turnover

Salmon calcitonin is a potent inhibitor of osteoclastic activity. The effect of calcitonin in elderly women with high bone turnover at higher risk of developing osteoporosis has not been studied. To investigate acute effects of calcitonin treatment on bone resorption markers in elderly women, we conducted a randomized trial in women >65 years of age with high bone turnover assessed as urinary N-telopeptide of type-I collagen (NTx) levels 1 SD higher than mean premenopausal levels, which was irrespective of bone density. A total of 98 elderly women were randomly assigned to receive either 200 IU calcitonin nasal spray (n = 75) with calcium (500 mg) and vitamin D (200 IU) or calcium and vitamin D (n = 23) alone for 6 months. Blood and urine samples were collected at 0, 2, 4, and 6 months and analyzed for urinary NTx and serum C-telopeptide of type-1 collagen (CTx). At baseline, mean age was 72.1 ± 4.7 (mean ± SD) in the calcitonin group and 72.2 ± 6 years in the control group. The spine and total hip BMD, serum PTH levels and urinary calcium/creatinine ratios were similar in both groups. Mean BMD was in the osteopenic range in both groups. Calcitonin treatment resulted in significant decreases in serum CTx levels, 2, 4 and 6 months after treatment as compared to baseline, and after 4 and 6 months as compared to controls. A maximum decrease from baseline of 33% was seen at 6 months. The urinary resorption marker, urine NTx, showed a significant decrease in the calcitonin group when compared to baseline only at the 6-month time point. Analysis of least significance change (LSC) showed that 70% of calcitonin patients were categorized as responders using serum CTx after 6 months of treatment. We conclude that 200 IU calcitonin effectively decreases bone resorption within 60 days of therapy, thus preventing further bone loss in elderly women who are at a high risk of developing osteoporosis.     

Markers of Bone and Calcium Metabolism Following Gastric Bypass and Laparoscopic Adjustable Gastric Banding

BACKGROUND: Several studies have suggested that morbid obesity is associated with vitamin D deficiency and elevated parathyroid hormone (PTH). Studies have also suggested that there is an increase in vitamin D deficiency, bone resorption, and elevated PTH after gastric bypass surgery. Few studies have evaluated markers of bone and calcium metabolism after laparoscopic adjustable gastric banding or compared these results to those after gastric bypass. METHODS: Data on all patients undergoing primary gastric bypass (GBP; n = 979) and laparoscopic adjustable gastric banding (LAGB; n = 269) procedures at a tertiary-referral center from June 1996 through March 2005 were reviewed from a prospective database. Only patients with 25OH vitamin D levels available were included in this study (n = 534; GBP = 403, LAGB = 131). All patients were advised to take at least 1,200 mg calcium and 800-1,200 IU of vitamin D daily before and subsequent to their operation. Markers for bone metabolism [25OH Vitamin D, corrected serum calcium, alkaline phosphatase (AP), and PTH] were evaluated preoperatively and 3, 6, 12, and 24 months postoperatively. An analysis of variance and chi-square were performed to determine differences between the operative groups. Linear regression analysis was performed to evaluate the relationship between preoperative body mass index (BMI) and 25OH vitamin D and PTH levels and between percent excess weight loss and 25OH vitamin D and PTH after surgery. RESULTS: Sixty-four percent of all patients presented with vitamin D deficiency (<20 ng/ml) and 14% presented with elevated PTH preoperatively. Mean 25OH vitamin D levels and AP levels increased significantly after GBP surgery (vitamin D, 17 to 25 ng/ml 12 months post-op; AP, 80 to 90 IU/L 24 months post-op). Corrected calcium levels remained within normal limits and showed no change over time after both procedures. AP levels significantly increased from 76 IU/l preoperatively to 82 IU/l 6 months after LAGB surgery and then decreased to 59 IU/l 24 months after LAGB surgery. Linear regression analysis of preoperative vitamin D, PTH, and BMI values showed a significant positive relationship between initial BMI and PTH (r = 0.29) and a significant negative relationship between vitamin D and initial BMI (r = -0.19). A significant positive linear relationship between vitamin D and percent excess weight loss was evident 12 and 24 months after GBP surgery (r = 0.39 and 0.57, respectively). A negative relationship was evident between PTH and vitamin D 6 months after GBP surgery (r = -0.35) and 12 months after LAGB surgery (r = -0.61). CONCLUSIONS: These findings suggest that morbid obesity is associated with vitamin D deficiency, and elevated PTH and with adequate supplementation, GBP, and particularly LAGB, patients can improve their bone metabolism abnormalities related to obesity. Furthermore, adequate supplementation for GBP patients may attenuate the increased risk for bone loss associated with malabsorption from the bypass.     

Consumption of a high calcium mineral water lowers biochemical indices of bone remodeling in postmenopausal women with low calcium intake

Many postmenopausal women have a calcium intake far below the recommended amount and, in addition to attempting to improve their diet, need a calcium supplement. The aim of the study was to assess the effects of the consumption of a high calcium mineral water (HCaMW) on biochemical indices of bone remodeling in postmenopausal women with low Ca intake. A 6-month randomized double-blind placebo-controlled trial was designed to assess the effects of a daily consumption of 1 liter of a HCaMW (596 mg Ca/l) on serum parathyroid hormone (PTH) and biochemical markers of bone remodeling in postmenopausal women with a dietary Ca intake lower than 700 mg/day. The placebo group drank 1 liter of a mineral water with a low calcium content (10 mg/l). One hundred eighty healthy women were recruited (mean age: 70.1±4.0 years); 152 completed the 6-month trial. The changes from baseline of biochemical indices after 6 months consisted of a significant 14.1% decrease of serum PTH, osteocalcin (–8.6%), bone alkaline phosphatase (–11.5%), serum (–16.3%) and urine (–13.0%) type-1 collagen C-telopeptide in the HCaMW group compared to the placebo group, where all biochemical indices increased after 6 months. The additive effect of a small vitamin D supplement (400 iu/day) was also evaluated. In women receiving vitamin D in addition to HCaMW, the decrease in bone indices was not found to be greater than in women drinking only the HCaMW. A daily supplement of 596 mg of Ca through the consumption of 1 l of HCaMW was able to lower serum PTH and the indices of bone turnover in postmenopausal women with a low Ca intake. This could contribute to the repair of calcium deficiency and to the reduction of age-related bone loss in this population.This study was supported by a grant from Evian.     

Heated oyster shell-seaweed calcium (AAA Ca) on osteoporosis

A randomized, prospective, double-blind test was carried out to compare the effects of heated oyster shell-seaweed calcium (AAA Ca), calcium carbonate, and placebo in 58 elderly, hospitalized women with the mean age of 80 divided into three groups. Group A received 900 mg/day Ca as AAA Ca, Group B 900 mg/day Ca as CaCO₃, and Group C placebo besides regular hospital diet containing approximately 600 mg Ca/day for 24 months. From the 25th to the 30th month, all groups were given AAA Ca. Lumbar spine and radial bone mineral density (BMD) were measured at 3-month intervals. Urinary Ca/Cr and serum alkaline phosphatase, intact and midportion serum parathyroid hormone (PTH), and calcitonin were also measured at intervals. From the 6th to the 24th month of the study, the ratio of lumbar spine BMD (L₂–L₄ by DPX, Lunar) to the basal pretest value was consistently and significantly higher in Group A than Group C but not higher in Group B than in Group C. PTH, measured 12 months after the beginning of the study, was lower in Group A than in Group C, but no significant difference was found between Groups B and C. At 3 months after the placebo was switched to AAA Ca in Group C, serum PTH was significantly decreased from the level during placebo supplement. Morning urine Ca/Cr decreased in Groups A after 18 months and in B after 12 months, but not in C. Serum alkaline phosphatase decreased in Group A significantly compared with Group C, but not in Group B. AAA Ca appears to be effective for increasing BMD in elderly subjects.     

Changes in serum fibroblast growth factor 2 in patients with glucocorticoid-induced osteoporosis treated with human parathyroid hormone (1–34)

Since the ability of parathyroid hormone (PTH) to increase osteoblast maturation and activity is associated with basic fibroblast growth factor (bFGF) we determined the changes in serum bFGF levels in patients treated with human parathyroid hormone (hPTH) (1–34) for 12 months and 12 months follow up. All studied subjects (n=51) had postmenopausal osteoporosis, had been receiving long-term treatment with glucocorticoid plus estrogen or estrogen/progesterone and were randomly allocated either to a group receiving hPTH, 400 U/day (n=28), or to a control group (n=23). Osteocalcin (OST), bone-specific alkaline phosphatase (BSAP) and bFGF were monitored at the baseline, every 3 months for 18 months, and at 24 months. In the hPTH group, OST increased by more than 150% above baseline at 3 months and was maintained at this level throughout the treatment period. BSAP had increased more than 80% over the baseline level at 3 months and was maintained at 90% above baseline for the next 9 months. bFGF levels had increased by 45% at 3 months, 60% at 6 to 9 months (P<0.05) and had increased more than 90% from baseline by 12 months (P<0.05). We found that daily hPTH injections increased bFGF levels. These results support the hypothesis that up-regulation of bFGF could play a role in the osteoblastic response to PTH.     

Oral vitamin D supplementation reduces the incidence of eucalcemic PTH elevation after surgery for primary hyperparathyroidism

BACKGROUND: As many as 43% of patients will have normocalcemic intact parathyroid hormone (PTH) elevation after undergoing curative parathyroidectomy for primary hyperparathyroidism. This phenomenon may be due in part to an absolute or relative deficiency of vitamin D, which is under-recognized in patients with primary hyperparathyroidism. METHODS: From September 1, 2004, to September 30, 2005, 86 consecutive patients underwent parathyroidectomy for primary sporadic hyperparathyroidism (psHPT). The patients were segregated into 2 groups based on postoperative management. Group 1 was composed of 26 patients who received routine oral calcitriol and calcium carbonate postoperatively. The 60 patients in the second group (group 2) received calcium carbonate postoperatively at the discretion of the primary surgeon. RESULTS: A total of 85 patients (99%) achieved postoperative cure with sustained reduction in serum calcium. Within 30 days postoperatively, mean serum PTH levels normalized in both groups (41 +/- 31 vs 39 +/- 31 pg/ml; P = .91). However, at 1 to 3 months postoperatively, mean serum calcium levels remained similar (9.5 +/- 0.7 vs 9.3 +/- 0.5 mg/dl; P = .39) whereas mean serum PTH levels in groups 1 and 2 were 43 +/- 25 pg/ml and 67 +/- 45 pg/ml (P = .02), respectively. At 4 to 6 months postoperatively, mean PTH was again higher in group 2 (36 +/- 22 vs 67 +/- 35; P = .03), whereas mean serum calcium levels were normal (9.2 +/- 0.8 vs 9.6 +/- 0.4 mg/dl; P = .18). The incidence of postoperative normocalcemic PTH elevation was significantly higher in group 2 at 1 to 3 months (14% vs 39%; P = .04) and at 7 to 12 months (22% vs 83%; P = .04). CONCLUSIONS: Vitamin D supplementation following parathyroidectomy for primary hyperparathyroidism reduces the incidence of postoperative eucalcemic PTH elevation.     

Suppression of C-Terminal Telopeptide in Hypovitaminosis D Requires Calcium as Well as Vitamin D

We compared the effects of oral calcium and vitamin D separately and together on relevant variables in 22 postmenopausal volunteers with initial serum 25OHD levels below 60 nmol/L. Subjects were allocated randomly to two regimens: group 1 received 1 week of calcium 1,000 mg, followed by 7 weeks with additional vitamin D₃ 1,000 i.u. daily; group 2 received 7 weeks of D₃ 1,000 i.u. daily, followed by 1 week with additional calcium 1,000 mg. We measured serum calcium, phosphate, PTH, 25OHD, CTX, and ALP at baseline and after 1 and 8 weeks in group 1 and after 7 and 8 weeks in group 2. There were no significant changes in ALP from either vitamin D or calcium. Calcium caused significant elevation of serum 25OHD as well as major suppression of serum CTX, which could not easily be accounted for by suppression of PTH. Vitamin D caused no significant change in any variable except elevation of serum 25OHD. The suppressive effect of calcium (whether given first or second) on serum CTX was threefold greater than that of vitamin D (whether given first or second) (P < 0.001), although their suppressive effects on serum PTH were the same. Calcium and vitamin D yielded greater and more significant effects on all variables (except ALP) than either treatment alone. We suggest that calcium may elevate serum 25OHD by prolonging its half-life and that it may have an inhibitory effect on bone resorption independent of, or in addition to, its suppression of PTH.