Vitamin D status after total gastrectomy

Influencing factors on serum 25-hydroxyvitamin D3 levels in Japanese chronic hepatitis C patients

Background

Serum 25-hydroxyvitamin D₃ levels are generally lower in chronic hepatitis C patients than in healthy individuals. The purpose of this study is to clarify the factors which affect serum 25-hydroxyvitamin D₃ levels using data obtained from Japanese chronic hepatitis C patients.

Methods

The subjects were 619 chronic hepatitis C patients. Serum 25-hydroxyvitamin D₃ levels were measured by using double-antibody radioimmunoassay between April 2009 and August 2014. Serum 25-hydroxyvitamin D₃ levels of 20 ng/mL or less were classified as vitamin D deficiency, and those with serum 25-hydroxyvitamin D₃ levels of 30 ng/mL or more as vitamin D sufficiency. The relationship between patient-related factors and serum 25-hydroxyvitamin D₃ levels was analyzed.

Results

The cohort consisted of 305 females and 314 males, aged between 18 and 89 years (median, 63 years). The median serum 25-hydroxyvitamin D₃ level was 21 ng/mL (range, 6–61 ng/mL). On the other hand, the median serum 25-hydroxyvitamin D₃ level in the healthy subjects was 25 ng/mL (range, 7–52), being significantly higher than that those in 80 chronic hepatitis C patients matched for age, gender, and season (p = 1.16 × 10⁻⁸). In multivariate analysis, independent contributors to serum 25-hydroxyvitamin D₃ deficiency were as follows: female gender (p = 2.03 × 10⁻⁴, odds ratio = 2.290, 95 % confidence interval = 1.479–3.545), older age (p = 4.30 × 10⁻⁴, odds ratio = 1.038, 95 % confidence interval = 1.017–1.060), cold season (p = 0.015, odds ratio = 1.586, 95 % confidence interval = 1.095–2.297), and low hemoglobin level (p = 0.037, odds ratio = 1.165, 95 % confidence interval = 1.009–1.345). By contrast, independent contributors to serum 25-hydroxyvitamin D₃ sufficiency were male gender (p = 0.001, odds ratio = 3.400, 95 % confidence interval = 1.635–7.069), warm season (p = 0.014, odds ratio = 1.765, 95 % confidence interval = 1.117–2.789) and serum albumin (p = 0.016, OR = 2.247, 95 % CI = 1.163–4.342).

Conclusions

Serum 25-hydroxyvitamin D₃ levels in chronic hepatitis C Japanese patients were influenced by gender, age, hemoglobin level, albumin and the season of measurement.

Serum 25(OH)D3 levels affect treatment outcomes for telaprevir/peg-interferon/ribavirin combination therapy in genotype 1b chronic hepatitis C

BACKGROUND

Close relationships between chronic hepatitis C and vitamin D levels have been reported. For genotype 1b infection, the current standard of care is pegylated interferon/ribavirin therapy combined with a protease inhibitor. The present study analyzed the relationship between outcomes of triple therapy and serum 25(OH)D3 levels.

METHODS

Factors contributing to sustained virological response were investigated in 177 patients with chronic hepatitis C who received telaprevir-based triple therapy in this prospective study.

RESULTS

The sustained virological response rate was 86.9% in patients with 25(OH)D3 levels of >18 ng/ml; this was higher than the 66.7% in patients with 25(OH)D3 levels of ≤ 18 ng/ml (P=0.003). 25(OH)D3 levels and IL28B genotype were identified as significantly independent factors contributing to sustained virological response. The sustained virological response rate did not differ according to 25(OH)D3 levels in patients with the IL28B major genotype. The sustained virological response rate was 64.9% in patients with the IL28B minor genotype and 25(OH)D3 levels of >18 ng/ml, and was 38.5% in those with decreased 25(OH)D3 levels (P=0.045).

CONCLUSIONS

In triple therapy, 25(OH)D3 levels were an independent factor contributing to sustained virological response. Of particular note, the sustained virological response rate was significantly lower in patients with the IL28B minor genotype.

Does bone change after biliopancreatic diversion?

This prospective study evaluated bone changes after biliopancreatic diversion (BPD) consisting of a distal gastrectomy, a 250 cm alimentary channel, and a 50 cm common channel. Thirty-three consecutive patients had clinical, biochemical, and bone mineral density analysis before surgery and 4 and 10 years after surgery. Iliac crest bone biopsies and special tests including parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25-OH(2)-D), bone-specific alkaline phosphatase (BAP), and osteocalcin were obtained at surgery and 4 years postoperatively. Over the years, with close metabolic surveillance, additional calcium and vitamin D were given as indicated. After BPD, serum levels of calcium and vitamin D were decreased and serum levels of PTH, BAP, and osteocalcin were increased. Bone turnover and mineralization were both increased. Mean osteoid volume (P < 0.0007) and bone formation rate in relation to bone volume (P < 0.02) were increased. Static measures of bone were altered as follows: cortical thickness decreased (P < 0.01) and trabecular bone volume increased (P < 0.01). Ten years after surgery, overall bone mineral density was unchanged at the hip and was decreased by 4% at the lumbar spine. Overall fracture risk, based on the Z score, was unchanged. Preoperative factors predicting bone loss included menopause, smoking, and preexisting osteopenia. An elevated level of 1,25-OH(2)-D was also found to be a predictor of future bone loss (r = 0.40; P < 0.002). After surgery, a greater increase in bone markers and bone turnover was associated with an increased risk of bone loss. Although elevated osteocalcin levels were associated with overall bone loss (r = 0.52; P < 0.002), lower albumin levels were associated only with bone loss at hip level (r = 0.44; P < 0.02), whereas lower calcium levels were associated only with the loss at the lumbar spine (r = 0.39; P < 0.02). Ten years after surgery, bone loss at the hip continued to depend on albumin levels (r = 0.37; P < 0.03). We concluded that bone was relatively tolerant to the metabolic changes due to BPD. Provided that there is close surveillance for metabolic disturbances, the use of appropriate supplements, and the avoidance of malnutrition, the beneficial effects of surgery far outweigh the risk of postoperative bone disease.

Calcium regulation and bone mass loss after total gastrectomy in pigs

OBJECTIVE

Total gastrectomy often results in postgastrectomy bone disease with decreased bone mass and increased fracture risk. To further elucidate the mechanisms of postgastrectomy bone disease, the authors investigated calcium metabolism and bone mineral density after total gastrectomy in pigs.

SUMMARY BACKGROUND DATA

Postgastrectomy bone disease can present as osteomalacia, osteoporosis in excess of normal aging, or a combination of both. The underlying mechanisms are insufficiently understood and need further investigation.

METHODS

Growing minipigs were gastrectomized and compared with fed-matched, sham-operated control p gs for 1 year. Calcium absorption, serum calcium, parathyroid hormone, 25-(OH)-vitamin D, 1,25-(OH)2-vitamin D, alkaline phosphatase, and computed tomography bone mineral density were measured in three monthly intervals.

RESULTS

Total gastrectomy resulted in impaired calcium absorption, reduced serum calcium and 25-(OH)-vitamin D, increased parathyroid hormone and 1,25-(OH)2-vitamin, and reduced bone mineral density compared with fed-matched, sham-operated control pigs.

CONCLUSIONS

The authors data indicate that a reduced serum calcium activates counter-regulatory mechanisms, resulting in calcium mobilization from the bone. Possibly, calcium and vitamin D supplementation after total gastrectomy might prevent postgastrectomy bone mass loss.

Long-term changes in bone mass after partial gastrectomy in a well-defined population and its relation to tobacco and alcohol consumption

We studied the long-term effect of partial gastrectomy on bone metabolism in a well defined population of gastrectomized patients compared to an age- and sex-matched group with unoperated peptic ulcers (controls). We selected 61 individuals between 61 and 70 years old at the time of investigation who had been operated on at the same surgical department an average of 20 years earlier. Compared to unoperated ulcer patients, we found reduced bone mass of the distal forearm in the operated groups. The serum level of calcidiol was significantly reduced in Billroth I (BI) operated women and insignificantly lower in the other operated groups. In men, ionized and total calcium was reduced, and 24-hour excretion of hydroxyproline in the urine as increased (p < 0.05). Biochemical signs of osteomalacia were found in one gastrectomized patient only. There were no significant differences between operated and unoperated patients in serum levels of alkaline phosphatases, iPTH, calcitriol, or the 24-hour urine calcium/creatinine excretion, even though there was a trend toward lower 24-hour urine calcium/creatinine ratio and increased levels in iPTH in the operated groups. There was no correlation between the daily alcohol consumption or cumulative tobacco consumption and bone mineral content in each group. Gastrectomized women smoked much more than control women, and smoking may be a determinant factor for the bone loss, as it is in healthy persons. Operated patients had a lower intake of milk products. All patients were exposed to sunlight for more than 3 hours/week. It is suggested that osteopenia after gastrectomy might be caused by calcium depletion rather than lack of vitamin D. The consumption of tobacco but not of alcohol was connected to bone loss.

Bone disorders following total gastrectomy

Bone disorders following gastrectomy were studied by measuring absolute and relative bone mineral density of the Wards triangle, serum 1,25-(OH)2-D, alkaline phosphatase, and total serum calcium. The subjects were 20 males who had undergone total gastrectomy not more than three months previously (group A1). Seventeen of these patients were reviewed three years later (group A2). Absolute and relative bone density were significantly lower in group A2 than in A1 (0.52 +/- 0.011 g/cm2 versus 0.6 +/- 0.014 g/cm2, P < 0.01 and 85.5 +/- 1.4% age-matched control versus 95 +/- 1.3%, P < 0.01). 1,25-(OH)2-D was significantly lower in group A2 than in group A1 (14.3 +/- 0.97 pg/ml versus 20.6 +/- 1.02 pg/ml, P < 0.01). There was no difference in alkaline phosphatase and calcium serum concentration. The mean weight loss was 6.26 +/- 0.57% over the follow-up period, and weight loss correlated with absolute and relative bone density (r = -0.74, P < 0.01). There was a positive correlation between 1,25-(OH)2-D and absolute or relative bone density (r = 0.67, r = 0.62 and P < 0.01). These data suggest that bone density decrease has already occurred three years after total gastrectomy and is positively correlated to 1,25-(OH)2-D deficiency. As no differences in serum alkaline phosphatase and serum calcium concentration were found, these factors are of little value for the early detection of postgastrectomy bone disorders, whereas weight loss is a valuable screening parameter.

Calcium regulating hormones and bone mineral content in patients after subtotal gastrectomy

Twenty-nine men who had undergone Billroth I gastrectomy and 19 men who had undergone Billroth II gastrectomy were studied to examine the changes in their calcium regulating hormones and bone mineral content following surgery. The serum calcium and phosphate concentrations in the patients with Billroth I and Billroth II were normal. The Billroth II group had an elevated level of serum alkaline phosphatase and reduced bone mineral content. The 24,25(OH)2D concentration was reduced (P < 0.01) and 25(OH)D and 1,25(OH)2D concentrations were increased (P < 0.01, P < 0.05, respectively) in the Billroth II group. It was suggested by our study that the Billroth II patients had a reduced bone mineral content and an elevated 1,25(OH)2D concentration. Therefore, the pathophysiology of postgastrectomy bone metabolic disease is not due to vitamin D deficiency, but may instead be due to reduced calcium absorption in the intestine.

The role of 1,25-dihydroxyvitamin D in the mechanism of acquired vitamin D deficiency

OBJECTIVE

We wished to assess the effect of changes in the plasma concentration of 1,25-dihydroxyvitamin D on the plasma elimination half-time for 25-hydroxyvitamin D in man.

DESIGN

The turnover of 25-hydroxyvitamin D in plasma was investigated after intravenous doses of the radioactively labelled metabolite had been given to a group of patients (n = 17) with disorders of bone and mineral metabolism before and after oral treatment with calcium or 1,25-dihydroxyvitamin D.

PATIENTS

Seven patients with post-menopausal osteoporosis, five with hypoparathyroidism, three with hypophosphataemic osteomalacia, one with renal osteodystrophy and one patient with coeliac disease were studied.

MEASUREMENTS

Intravenous injections of 3H-labelled 25-hydroxyvitamin D were given and plasma elimination half-time assessed over periods of 4-14 days during which frequent measurements of plasma calcium, phosphate, parathyroid hormone, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were made. Changes in the plasma elimination half-time for 3H-25-hydroxyvitamin D before and after treatment with calcium and 1,25-dihydroxyvitamin D were evaluated by non-parametric statistical analysis.

RESULTS

The elimination half-time for 3H-25-hydroxyvitamin D in plasma was significantly shortened by raising the circulating concentration of 1,25-dihydroxyvitamin D. Conversely, in a patient with intestinal malabsorption of calcium, the metabolic clearance of 3H-25-hydroxyvitamin D was prolonged when the concentration of 1,25-dihydroxyvitamin D in plasma was decreased by suppressing secondary hyperparathyroidism with large calcium supplements. In the longer-term studies (n = 10) there was a highly significant inverse relation (r = -0.88, P < 0.001) between the change in the plasma concentration of 1,25-dihydroxyvitamin D and the induced change in the elimination half-time of 3H-25-hydroxyvitamin D. There was also a significant correlation (r = 0.66, p < 0.0025) between the observed fall in the plasma concentration of unlabelled 25-hydroxyvitamin D and the predicted fall calculated from the measured value for the half-time of the 3H-labelled metabolite. In acute studies in patients with post-menopausal osteoporosis (n = 7), enhanced metabolic inactivation of 3H-25-hydroxyvitamin D was detectable within 24 hours of oral administration of 1,25-dihydroxyvitamin D.

CONCLUSIONS

The effect of 1,25-dihydroxyvitamin D on the catabolism of 25-hydroxyvitamin D can contribute to the development of vitamin D deficiency in many clinical disorders. When the natural supply of vitamin D is limited by sunlight deprivation, a sustained increase in the plasma concentration of 1,25-dihydroxyvitamin D due to primary or secondary hyperparathyroidism will lead to accelerated depletion of vitamin D stores.

Metabolic bone disease in asymptomatic men after partial gastrectomy with Billroth II anastomosis

We sought to determine whether gastric surgery might be associated with metabolic bone disease in a well-characterized population, and if so to explore its etiology. Sixteen asymptomatic middle-aged men who had had partial gastrectomy with Billroth II anastomosis but no other risk factors for metabolic bone disease were compared with unoperated healthy controls. Studies included a dietary survey, biochemical tests of bone and mineral metabolism, radiographs of the spine, determinations of bone mineral content, and bone histomorphometry. The gastric surgery subjects exhibited frequent vertebral fractures and an unusual constellation of bone abnormalities characterized by decreased bone mineral content and hyperosteoidosis without evidence of osteomalacia. Although serum immunoreactive parathyroid hormone and 25-hydroxyvitamin D levels were not different, 1,25-dihydroxyvitamin D levels were significantly higher (p = 0.037), and 24,25-dihydroxyvitamin D levels were significantly lower (p less than 0.0001) in subjects than in controls. Partial gastrectomy with Billroth II anastomosis may be associated with asymptomatic but clinically important metabolic bone disease. The pathophysiology is uncertain, but appears to involve alterations in vitamin D metabolism.

The physiology and pathophysiology of vitamin D

The vitamin D endocrine system plays an important role in the maintenance of normal calcium homeostasis. Abnormalities of this system occur in many conditions, such as rickets, osteomalacia, hypoparathyroidism, and hyperparathyroidism. The diagnosis and treatment of these disorders will be facilitated if the clinician understands the general mechanisms by which defects in vitamin D metabolism and action occur. We review this information and discuss the use and limitations of vitamin D metabolite assays for diagnosis of clinical disorders of mineral metabolism.