Bone mineral density in patients taking H2-receptor antagonist

Medications as a Risk Factor for Fragility Hip Fractures: A Systematic Review and Meta-analysis

Fragility hip fractures and their associated morbidity and mortality pose a global healthcare problem. Several pharmaceutical products have been postulated to alter bone architecture and contribute to fragility hip fractures. We searched four electronic databases from inception to September 2017. Inclusion criteria were the following: (1) adult patients with fragility hip fractures, (2) full text in English, (3) minimum one-year follow-up, and (4) reporting of at least one risk factor. To minimize heterogeneity among the studies, we performed subgroup analyses. Whenever heterogeneity remained significant, we employed random effect meta-analysis for data pooling. Thirty-eight studies were included, containing 1,244,155 subjects and 188,966 cases of fragility hip fractures. Following medications were significantly associated with fragility hip fractures: Antidepressants (OR 2.07, 95% CI 1.98-2.17), antiparkinsonian drugs (OR 2.21, 95% CI 1.15-4.24), antipsychotic drugs (OR 2.0, 95% CI 1.50-2.66), anxiolytic drugs (OR 1.44, 95% CI 1.19-1.75), benzodiazepines (OR 1.84, 95% CI 1.26-2.69), sedatives (OR 1.33, 95% CI 1.14-1.54), systemic corticosteroids (OR 1.65, 95% CI 1.37-1.99), H₂ antagonists (OR 1.21, 95% CI 1.18-1.24), proton pump inhibitors (OR 1.41, 95% CI 1.16-1.71), and thyroid hormone (OR 1.29, 95% CI 1.13-1.47). Hormone replacement therapy with estrogen (HRT) was associated with decreased risk of hip fracture (OR 0.80, 95% CI 0.65-0.98). There are several medications associated with sustaining a fragility hip fracture. Medical interventions should be considered for patients on these medications, including information about osteoporosis and fracture prevention.

The Association Between Prolonged Proton Pump Inhibitors Use and Bone Mineral Density

Background and study aim

Chronic use of proton-pump inhibitors (PPIs) has become a mainstay of therapy in common gastrointestinal diseases. A causal relationship between chronic PPI use and development of osteoporosis remains unproven. The aim of this study was to determine whether PPI users are more likely to develop alterations in bone density.

Patients and methods

In an analytical cross sectional study, patients who used PPIs for more than 2 years because of long-term gastroesophageal reflux disease (GERD) were recruited. PPI users were healthy people except for GERD. The compression group was randomly derived from an age-, sex- and physical activity-matched group from a healthy population in the National Registry of Osteoporosis who had not used PPIs in the previous 2 years. Bone mineral density was measured with dual-energy X-ray absorptiometry. Data regarding BMD and bone mineral content (BMC) of three regions: femoral neck, total hip, and the lumbar spine (L1-L4) were gathered and recorded. The World Health Organization (WHO) classification was used for definition of osteopenia and osteoporosis.

Results

A total of 394 participants (133 PPI users and 261 comparison group) were enrolled. The median duration of PPI use was 6.7 (2–31) years. The mean age ± SD of PPI users and comparison group was 48.38 ± 11.98 and 47.86 ± years, respectively (P = 0.681). There was no significant difference in baseline characteristics and age distribution between the two groups. The BMC levels were significantly lower in PPI users in all three regions: lumbar spine, total hip, and femoral neck (P<0.001). There were no significant differences in the T-scores between the two groups except for femoral neck (P<0.001). Osteoporosis in femoral neck was significantly higher in PPI users than in comparison group.

Conclusion

This study showed that long-term use of PPIs is associated with lower BMC and higher rate of osteoporosis in the femoral neck. However, more studies with longitudinal evaluation should be performed to clarify this causal relationship. Until then, it is advised not to overuse PPIs because of the possible increase in risk of osteoporosis and the risk of fractures. We also recommend using the BMC levels as a quantitative measure in addition to T scores in analysis and reporting similar studies.

Deficiency of micronutrients in patients affected by chronic atrophic autoimmune gastritis: A single-institution observational study

BACKGROUND

Chronic atrophic autoimmune gastritis (CAAG) leads to vitamin B₁₂ deficiency, but other micronutrient deficiencies are largely understudied.

AIMS

To investigate the prevalence of micronutrient deficiencies in CAAG patients and their potential relationship with the grading of gastric atrophy or entero-chromaffin-like cells hyperplasia or body mass index (BMI).

METHODS

From 2005 to 2016 a number of CAAG patients underwent regular follow-up with annual blood testing and upper gastrointestinal tract endoscopy every years.

RESULTS

Out of the 122 CAAG patients checked (100 F; median age 65 years), 76 presented nutritional deficiencies, single in 24 and multiple in 52 cases: a deficiency of B₁₂ and iron showed in 42 patients, 25-OH vitamin D lacked in 76 and folic acid in 6 cases. 25-OH vitamin D levels directly correlated with B₁₂ levels and were significantly lower in patients with macronodular than in those with linear or micronodular hyperplasia. No significant correlation was observed between B₁₂, folic acid or ferritin levels and BMI, blood gastrin levels, the grading of gastric atrophy or ECL cells hyperplasia.

CONCLUSIONS

25-OH vitamin D deficiency was the main one in CAAG patients: its correlation with B₁₂ deficiency may indicate underlying shared pathogenic mechanisms, although further studies are needed to confirm this hypothesis.

Relevance of vitamin D deficiency in patients with chronic autoimmune atrophic gastritis: a prospective study

Background

Chronic autoimmune atrophic gastritis (CAAG) is an autoimmune disease characterized by hypo/achlorhydria. A role of CAAG in the pathogenesis of nutritional deficiencies has been reported, therefore we hypothesized a possible association between CAAG and 25-OH-Vitamin D [25(OH)D] deficiency. Aim of the present study is to evaluate the prevalence of 25(OH)D deficiency in CAAG patients. Methods: 87 CAAG patients (71 females; mean age 63.5 ± 12.8 years) followed at our Centre from January 2012 to July 2015 were consecutively evaluated. 25(OH)D, vitamin B₁₂, parathormone, and calcium were measured in all the CAAG patients. The results were compared with a control group of 1232 healthy subjects.

Results

In the CAAG group the mean 25(OH)D levels were significantly lower than in the control group (18.8 vs. 27.0 ng/ml, p < 0.0001). 25(OH)D levels < 20 ng/ml was observed in 57 patients, while levels < 12.5 ng/ml in 27 patients. A significant correlation between vitamin B₁₂ values at diagnosis and 25(OH)D levels was observed (r_s = 0.25, p = 0.01). Interestingly, the CAAG patients with moderate/severe gastric atrophy had lower 25(OH)D values as compared to those with mild atrophy (11.8 vs. 20 ng/ml; p = 0.0047). Moreover, the 25(OH)D levels were significantly lower in CAAG patients with gastric carcinoid as compared to those without gastric carcinoid (11.8 vs. 19.8 ng/ml; p = 0,0041).

Conclusion

Data from the present study showed a significant reduction of 25(OH)D levels in CAAG patients and a possible impairment of vitamin D absorption in CAAG may be postulated. Any implication to the genesis of gastric carcinoids remains to be elucidated.

Spatial distribution of osteoblast activating peptide in the rat stomach

Osteoblast activating peptide (OBAP) was previously reported to be expressed in the rat stomach and to have a vital role in osteogenesis, but its distribution in rat stomach has not been determined. Thus, the aim of the present study was to identify the cell types expressing OBAP in the rat stomach. The stomachs of twelve 10-to-11-week-old male Jc1:SD rats were used. Samples were collected for immunohistochemistry, immunoelectron microscopy and dot blot assay. Immunohistochemical investigation revealed that OBAP was distributed mainly in parietal cells without any expression in chief cells, X/A-like cells or enterochromaffin-like cells. Moreover, OBAP-immunopositive cells were observed mainly in the upper and lower parts of the gastric gland. Significantly high optical density of immunopositive cells was observed in the upper and lower gastric gland regions. The dot blot assay confirmed that OBAP is secreted by parietal cells and that it is present in the gastric gland lumen. Immunoelectron microscopy demonstrated that OBAP was confined to the mitochondrial inner membrane within parietal cells and that the number of mitochondria in the upper and lower parts of the gastric epithelium was significantly larger than the number in the middle part of the gastric epithelium. Based on the results, it was concluded that OBAP is mainly produced by mitochondria of parietal cells in the upper and lower parts of the gastric epithelium. Moreover, the presence of OBAP in the gastric gland lumen suggests an exocrine mechanism of release.

A high-calcium diet failed to rescue an osteopenia phenotype in claudin-18 knockout mice

We have recently demonstrated that mice with disruption of claudin‐18 (Cldn‐18) gene exhibited osteopenia due to increased bone resorption (BR). In this study, we found that gastric pH was significantly higher in Cldn‐18 knockout (KO) mice compared to heterozygous control mice at 10 weeks of age. To test the possibility that the increased BR in the Cldn‐18 KO mice fed a normal‐Ca diet is a consequence of decreased Ca absorption caused by increased stomach pH, we subjected KO and control mice to a normal‐Ca and high‐Ca diet at birth. Serum Ca levels were significantly lower in Cldn‐18 KO mice compared to control mice at a normal‐Ca diet but not at high‐Ca diet. Dual energy X‐ray absorptiometry revealed that a high‐Ca diet significantly increased lumbar bone mineral density (BMD), but had no effect on femur/tibia BMD in both Cldn‐18 KO and control mice compared to a normal‐Ca diet. While a high‐Ca diet did not affect volumetric BMD, trabecular, and cortical parameters of the lumbar vertebra (LV) as measured by μCT, the size of the LV did increase, in both genotypes due to reduced BR. Comparison of the skeletal phenotype of high‐Ca Cldn‐18 KO and control mice revealed that an osteopenia phenotype seen at a normal‐Ca diet was still maintained at different skeletal sites in the KO mice till 10 weeks of age. In conclusion, our findings suggest that increased BR is likely caused by direct effects of a lack of Cldn‐18 on osteoclasts rather than gastric pH changes.

In this study, we examined if calcium deficiency caused by low‐gastric acidity was the cause of osteopenia phenotype observed in claudin‐18 (Cldn‐18) knockout (KO) mice. Our findings that high‐calcium diet did not rescue the osteopenia phenotype in Cldn‐18 KO mice suggest that increased bone resorption is likely caused by direct effects of a lack of Cldn‐18 on osteoclasts rather than gastric pH changes.

Fracture risk and bone mineral density reduction associated with proton pump inhibitors

Many patients receive prolonged proton pump inhibitor (PPI) therapy for upper gastrointestinal disorders, but the long-term safety of PPIs, particularly increased risk of hip and nonhip fractures, has been questioned. To summarize the current literature on the risk of bone mineral density (BMD) reduction and fracture associated with PPI therapy, we conducted a literature search to identify all pertinent studies from 1980-February 2011. A total of 14 observational studies were included in this review. Most studies evaluated the risk of fracture associated with prolonged PPI exposure. Eight studies found an increased fracture risk at the hip, and five studies found an increased fracture risk at the spine associated with PPIs. Three studies showed reduction in fracture risk associated with PPIs after discontinuation for 1 month-1 year. Three studies evaluated the risk of BMD reduction associated with PPIs but did not find consistent changes in baseline or subsequent BMD. The current data suggest a modest increase in the risk of hip fracture and vertebral fracture associated with PPIs, although some studies showed conflicting results. Further studies will be needed to determine whether the increased risk of fracture is due to PPI exposure or residual confounding.

Risk of fracture and pneumonia from acid suppressive drugs

A recently published systematic review and meta-analysis, incorporating all relevant studies on the association of acid suppressive medications and pneumonia identified up to August 2009, revealed that for every 200 patients, treated with acid suppressive medication, one will develop pneumonia. They showed the overall risk of pneumonia was higher among people using proton pump inhibitors (PPIs) [adjusted odds ratio (OR) = 1.27, 95% CI: 1.11-1.46, I² = 90.5%] and Histamine_-2 receptor antagonists (H₂RAs) (adjusted OR = 1.22, 95% CI: 1.09-1.36, I² = 0.0%). In the randomized controlled trials, use of H₂RAs was associated with an elevated risk of hospital-acquired pneumonia (relative risk 1.22, 95% CI: 1.01-1.48, I² = 30.6%). Another meta-analysis of 11 studies published between 1997 and 2011 found that PPIs, which reduce stomach acid production, were associated with increased risk of fracture. The pooled OR for fracture was 1.29 (95% CI: 1.18-1.41) with use of PPIs and 1.10 (95% CI: 0.99-1.23) with use of H₂RAs, when compared with non-use of the respective medications. Long-term use of PPIs increased the risk of any fracture (adjusted OR = 1.30, 95% CI: 1.15-1.48) and of hip fracture risk (adjusted OR = 1.34, 95% CI: 1.09-1.66), whereas long-term H₂RA use was not significantly associated with fracture risk. Clinicians should carefully consider when deciding to prescribe acid-suppressive drugs, especially for patients who are already at risk for pneumonia and fracture. Since it is unnecessary to achieve an achlorhydric state in order to resolve symptoms, we recommend using the only minimum effective dose of drug required to achieve the desired therapeutic goals.

Use of acid-suppressive drugs and risk of fracture: a meta-analysis of observational studies

PURPOSE

Previous studies have reported inconsistent findings regarding the association between the use of acid-suppressive drugs such as proton pump inhibitors (PPIs) and histamine 2 receptor antagonists (H(2)RAs) and fracture risk. We investigated this association using meta-analysis.

METHODS

We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library from inception through December 2010 using common key words. We included case-control, nested case-control, and cohort studies. Two evaluators independently reviewed and selected articles. We determined pooled effect estimates by using random-effects meta-analysis, because of heterogeneity.

RESULTS

Of 1,809 articles meeting our initial inclusion criteria, 5 case-control studies, 3 nested case-control studies, and 3 cohort studies were included in the final analyses. The pooled odds ratio (OR) for fracture was 1.29 (95% confidence interval [CI], 1.18-1.41) with use of PPIs and 1.10 (95% CI, 0.99-1.23) with use of H(2)RAs when compared with nonuse of the respective medications. Long-term use of PPIs increased the risk of any fracture (adjusted OR = 1.30; 95% CI, 1.15-1.48) and hip fracture risk (adjusted OR = 1.34; 95% CI, 1.09-1.66), whereas long-term H(2)RA use was not significantly associated with fracture risk.

CONCLUSIONS

We found possible evidence linking PPI use to an increased risk of fracture, but no association between H(2)RA use and fracture risk. Widespread use of PPIs with the potential risk of fracture is of great importance to public health. Clinicians should carefully consider their decision to prescribe PPIs for patients already having an elevated risk of fracture because of age or other factors.

Adverse effects of long-term proton pump inhibitor therapy

Proton pump inhibitors have an excellent safety profile and have become one of the most commonly prescribed class of drugs in primary and specialty care. Long-term, sometimes lifetime, use is becoming increasingly common, often without appropriate indications. This paper is a detailed review of the current evidence on this important topic, focusing on the potential adverse effects of long-term proton pump inhibitor use that have generated the greatest concern: B12 deficiency; iron deficiency; hypomagnesemia; increased susceptibility to pneumonia, enteric infections, and fractures; hypergastrinemia and cancer; drug interactions; and birth defects. We explain the pathophysiological mechanisms that may underlie each of these relationships, review the existing evidence, and discuss implications for clinical management. The benefits of proton pump inhibitor use outweigh its risks in most patients. Elderly, malnourished, immune-compromised, chronically ill, and osteoporotic patients theoretically could be at increased risk from long-term therapy.

The expression of PTHLH in human gastric mucosa enterochromaffin-like cells

BACKGROUND

Gastrectomy may disturb the body's mineral homeostasis, with osteopenia and osteoporosis being among the late outcomes. Parathyroid hormone-like hormone (PTHLH) was detected in rat gastric enterochromaffin-like (ECL) cells in 2005, and some researchers suggested that it was the hypothetical hormone gastrocalcin that is believed to lead to osteoporosis.

AIMS

Our objective was to learn whether PTHLH is expressed in human gastric ECL cells and to form a basic understanding about the relationship between PTHLH and gastrin.

METHODS

We collected normal human gastric mucosa specimens and serum samples from 28 patients.

RESULTS

RT-PCR and immunohistochemical analysis demonstrated weak expression of PTHLH in ECL cells at the RNA and protein levels. A low level of PTHLH expression was also found in the serum. Serum gastrin did have a significant positive correlation with the relative ratio of PTHLH mRNA to β-actin levels in gastric mucosa (rs=0.569, p=0.002).

CONCLUSIONS

This indicates that PTHLH has a low signal expression in human gastric ECL cells and that serum gastrin levels correlate with PTHLH RNA levels in gastric mucosa. Further work is needed to evaluate the functional role of PTHLH in ECL cells and to determine whether PTHLH is gastrocalcin.

Proton pump inhibitors and fracture risk: true effect or residual confounding?

Fracture is a major contributor to human morbidity and mortality, especially in the elderly. It has been discussed in the literature that conditions associated with decreased stomach acidity may lead to a decrease in intestinal calcium absorption and, consequently, to an increased fracture risk. In recent years, several observational studies reported a slightly increased fracture risk in association with the use of proton pump inhibitors (PPIs) and/or histamine H(2) receptor antagonists. It was the objective of this review to critically assess the available evidence linking PPI use to an increased fracture risk. A MEDLINE and EMBASE search from 1960 to June 2010 was performed to identify the relevant articles using predefined search terms. Because (i) there is no proven mechanism, (ii) the reported magnitude of the risk elevation associated with the use of PPIs was only weak, and (iii) the likelihood of residual confounding despite adjustment for known co-morbidities and drug use cannot be ruled out, we conclude that the currently available literature does not support the notion that the use of PPIs is causally related to a materially increased fracture risk in humans.

Hypochlorhydric stomach: a risk condition for calcium malabsorption and osteoporosis?

Malabsorption of dietary calcium is a cause of osteoporosis. Dissolution of calcium salts (e.g. calcium carbonate) in the stomach is one step in the proper active and passive absorption of calcium as a calcium ion (Ca(2+)) in the proximal small intestine. Stomach acid markedly increases dissolution and ionization of poorly soluble calcium salts. If acid is not properly secreted, calcium salts are minimally dissolved (ionized) and, subsequently, may not be properly and effectively absorbed. Atrophic gastritis, gastric surgery, and high-dose, long-term use of antisecretory drugs markedly reduce acid secretion and may, therefore, be risk conditions for malabsorption of dietary and supplementary calcium, and may thereby increase the risk of osteoporosis in the long term.

Effects of extracts of oxyntic mucosa in rat on the biological activity of osteoblasts

We explored the relationship between extracts of oxyntic mucosa (EOM) and the biological activity of osteoblasts in rats. We found that EOM could enhance the activity of bone formation in osteoblast. Our results suggest that EOM likely play a role in the cases of osteopenia induced by gastrectomy.

INTRODUCTION

Surgical removal of the stomach (gastrectomy) leads to osteopenia in animals and in humans. It was demonstrated that EOM could induce transient hypocalcaemia and stimulate an uptake of Ca(2+) into bone in rats. The main aim of this study has been to clarify whether this procedure was performed through osteoblast, which is responsible for bone formation.

METHODS

Osteoblasts were isolated, cultured, and identified in vitro. Preparing the rats' EOM and diluting into low, middle, and high concentrations, respectively. After osteoblasts were treated by different concentration EOMs or saline (for control), the intracytoplasm [Ca(2+)]i was measured by laser scanning confocal microscopy; the proliferation of osteoblast cells were detected with cell counting kit 8 (CCK-8); and the expressions of collagen type I and osteocalcin were assayed by reverse transcriptase polymerase chain reaction and Western blot.

RESULTS

EOMs were found to induce a dose-related rapid increase of intracytoplasm [Ca(2+)]i in osteoblasts and could stimulate osteoblasts to enhance proliferation and upregulate the expressions of collagen type I and osteocalcin significantly (p < 0.05) compared with the control group.

CONCLUSIONS

It was confirmed that EOM could stimulate osteoblasts to elevate the cytoplasm [Ca(2+)]i and promote the multiplication and the activity of bone formation in osteoblasts.

Proton pump inhibitors, osteoporosis, and osteoporosis-related fractures

Proton pump inhibitors (PPIs) are among the most commonly prescribed medications today with an excellent short-term safety profile. Recently, a number of studies from a variety of data sources have reported an association between PPI use and hip fractures. However, there is not yet any direct evidence of a causal link between PPI use and the development of hip fracture. In the following paper, we will review the recent studies which have described this association between PPI use and hip fracture, and discuss the evidence supporting the likelihood of this association being causal, using data from previous work on the effects of surgical and pharmacological inhibition of gastric acid secretion on calcium absorption and bone mineral density. We will conclude by summarizing the current state of evidence on the relationship between gastric acid inhibition and the risk of fracture, and suggest management strategies for patients who require the long-term use of gastric acid inhibiting medications who also may be at risk for metabolic bone disease and fracture.

The effect of proton pump-inhibiting drugs on mineral metabolism

Two recent studies have reported increased hip fracture rates with long-term proton pump inhibitor (PPI) use raising concerns about adverse effects of this class of drugs on mineral metabolism. One plausible mechanism by which PPIs could affect calcium economy and skeletal homeostasis is by impairing intestinal calcium absorption. In the long term, this could potentially lead to a negative whole body calcium balance, resulting in higher rates of bone loss and a greater risk of fragility fractures.

Increase in vertebral fracture risk in postmenopausal women using omeprazole

Proton pump inhibitors are taken by millions of patients for prevention and treatment of gastroesophageal diseases. Case-control studies have suggested that use of omeprazole is associated with an increased risk of hip fractures. The aim of this prospective study was to assess the risk of vertebral fractures in postmenopausal women using omeprazole. We studied 1,211 postmenopausal women enrolled in the Osteoporosis and Ultrasound Study from the general population. Information on omeprazole and other risk factors for fractures including prevalent fractures and bone mineral density was obtained at baseline. Vertebral fractures were assessed on X-rays obtained at baseline and at the end of the 6-year follow-up and analyzed centrally. At baseline, 5% of this population was using omeprazole. Age-adjusted rates for vertebral fractures were 1.89 and 0.60 for 100 person-years for omeprazole users and nonusers, respectively (P = 0.009). In the multivariate analysis, omeprazole use was a significant and independent predictor of vertebral fractures (RR = 3.50, 95% CI 1.14-8.44). The other predictors were age higher than 65 years (RR = 2.34, 95% CI 1.02-5.34), prevalent vertebral fractures (RR = 3.62, 95% CI 1.63-8.08), and lumbar spine T score </= -2.5 (RR = 2.38, 95% CI 1.03-5.49). Omeprazole use is associated with an increased risk of vertebral fractures in postmenopausal women. Further studies are required to determine the mechanism of the association between the underlying gastric disease, omeprazole use, and risk of osteoporotic fractures.

Antihistamine therapy and bone mineral density: analysis in a population-based US sample

BACKGROUND

Histamine may play an important role in bone turnover. The data regarding histamine 1 receptor antagonist (H1RA), histamine 2 receptor antagonist (H2RA), and bone mineral density in humans are sparse. We examined bone mineral density in subjects using histamine receptor antagonists in a representative US population-based sample from the Third National Health and Nutrition Examination Survey (1988-1994).

METHODS

Adult subjects aged 60 years and more using H1RA or H2RA who underwent dual energy x-ray absorptiometry scanning in the Third National Health and Nutrition Examination Survey were identified. We compared the femoral neck bone mineral density among users of these agents with nonusers in adjusted linear regression models that included known demographic, anthropometric, and medical risk factors for osteoporosis.

RESULTS

The mean age of the study subjects was 72.6 years; 52% were women and 59% were white. Among subjects with femoral neck bone mineral density measured, 199 used H1RAs, 297 used H2RAs, and 4162 were nonusers of histamine receptor antagonists. Femoral neck bone mineral density adjusting for age and gender and other covariates was slightly higher in H1RA users (0.74 g/cm(2)) versus nonusers (0.72 g/cm(2); P=.037). H2RA users showed slightly lower adjusted bone mineral density compared with nonusers (0.69 g/cm(2) vs 0.72 g/cm(2); P=.003), but bone densities were similar between H2RA users and nonusers when daily calcium intake exceeded 800 mg per day.

CONCLUSION

Femoral neck bone mineral density may be higher in H1RA users than nonusers among older adults. H2RA users with reduced calcium intake had lower bone mineral density than nonusers.

Proton pump-inhibiting drugs, calcium homeostasis, and bone health

Proton pump inhibitors (PPIs) are commonly used drugs, several of which are available without a prescription. Two recent studies have demonstrated increased hip fracture rates associated with PPI use. Theoretically, PPIs could impair intestinal calcium absorption resulting in increased rates of bone loss and a greater risk of fragility fracture.

Proton pump inhibitors, histamine H2 receptor antagonists, and other antacid medications and the risk of fracture

We studied the effect of proton pump inhibitors, histamine H(2) receptor antagonists, and other types of antacid drugs on fracture risk. All cases were subjects with any fracture sustained during the year 2000 (n = 124,655). For each case, three controls (n = 373,962) matched on age and gender were randomly drawn from the background population. The primary exposure variables were use of proton pump inhibitors, histamine H(2) antagonists, and other antacid drugs. Adjustments were made for several confounders, including diagnosis of an ulcer, nonsteroidal anti-inflammatory drug use, use of histamine H(1) antagonists, stomach resection, previous fracture, and use of corticosteroids. The effect of dose was examined by stratifying for cumulated dose (defined daily dose). Use of proton pump inhibitors was associated with an increase in fracture risk for use within the last year [odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.12-1.43 for overall fracture risk; OR = 1.45, 95% CI 1.28-1.65 for hip fractures; and OR = 1.60, 95% CI 1.25-2.04 for spine fractures). Histamine H(2) antagonists were associated with a decreased fracture risk if they had been used within the last year (OR = 0.88, 95% CI 0.82-0.95 for any fracture, OR = 0.69, 95% CI 0.57-0.84 for hip fractures). Other antacids were not associated with overall fracture risk but were associated with hip and spine fractures. Proton pump inhibitors appeared to be associated with a limited increase in fracture risk, in contrast to histamine H( 2 ) antagonists, which seemed to be associated with a small decrease in fracture risk. In all cases, the changes in risk estimates were small and the clinical significance was limited.

The pathophysiology of bone disease in gastrointestinal disease

Reduced bone mass and the increased risk of fracture in gastrointestinal diseases have a multifactorial pathogenesis. Undoubtedly, genetics play an important role, but other factors such as systemic inflammation, malnutrition, hypogonadism, glucocorticoid therapy in inflammatory bowel disease (IBD) and other lifestyle factors, such as smoking or being sedentary, may contribute to reduced bone mass. At a molecular level the proinflammatory cytokines that contribute to the intestinal immune response in IBD and probably also in coeliac disease are also known to enhance bone resorption. The discovery of the role of the receptor to activated NFkappaB (RANK) interaction with its ligand RANKL in orchestrating the balance between bone resorption and formation may link mucosal and systemic inflammation with bone remodelling, since RANK-RANKL are also involved in lymphopoiesis and T-cell apoptosis. Low circulating leptin in response to weight loss in any gastrointestinal disease may be an important factor in reducing bone mass. This report will summarize current concepts regarding gastrointestinal diseases (primarily IBD, coeliac disease and postgastrectomy states) and low bone mass and fracture.

Vagus-sparing gastric fundectomy in the rat: development of osteopenia, relationship to urinary phosphate and net acid excretion, serum gastrin and vitamin D

In man and experimental animals, partial and total gastrectomy and gastric vagotomies disturb extracellular mineral homeostasis, osteopenia being among the late outcomes. The sequence of events is complex and insufficiently understood. We report on the long-term effects of gastric fundectomy (FX; FX-1, n=11; sham-operated controls, n=14) sparing gastric vagal fibers at the lesser curvature in the rat, a procedure eliminating gastric acid production but preserving gastric reservoir function. After FX-1 there was a marked increase of gastrinemia [FX-1: 590 (SE 95); controls: 82 (5) pg-equiv/ml; P<0.001], serum 1,25-dihydroxyvitamin D [FX-1: 188 (17); controls: 86 (6) pg/ml; P<0.001], phosphaturia [FX-1: 32 (2); controls 23 (2) micromol/h; P<0.001] due to increased fractional phosphate clearance, elevated urinary net acid [FX-1: 21 (2); controls: 16 (1) micromol/h; P=0.03], and low urinary pH. The urinary excretion of hydroxyproline was increased [FX-1: 137 (15); controls: 99 (8) micromol/h; P=0.01], and crosslinks were also high. These changes were associated with a significant decrease of bone ash calcium, magnesium, and phosphorus. Bone histomorphometry revealed signs of high bone turnover. No signs of hyperparathyroidism were detectable. Acute stimulation of serum gastrin by gastric acid abolishing omeprazole failed to provoke extra-osseous changes, as seen in the long-term after fundectomy. It was concluded that the described type of fundectomy disturbs gastrinemia, acid-base and phosphorus metabolism, thereby initiating osteopenia. This animal model may be suitable for research into post-gastrectomy bone disease.

Bone abnormalities in gastrointestinal and hepatic disease

Bone is a dynamic tissue that undergoes constant remodeling in response to local and environmental stimuli. Bone mass is maintained by this delicate equilibrium between bone formation and bone resorption. In growing children, the balance is tilted toward bone formation until peak bone mass is achieved in the second decade of life. Alterations in bone metabolism can result in decreased bone mass (osteopenia and osteoporosis) or impaired mineralization of the bone protein matrix (rickets and osteomalacia). Diseases of the alimentary tract such as celiac disease, inflammatory bowel diseases, gastrectomy, cholestatic liver diseases, liver transplantation, and hepatitis C can affect bone mineralization, remodeling, or bone mass. This article presents a summary of recent reports concerning bone disorders associated with disorders of the liver and gastrointestinal tract.

Low bone mineral density after total gastrectomy in males: a preliminary report emphasizing the possible significance of urinary net acid excretion, serum gastrin and phosphorus

The bone mineral density (BMD) and the associated extracellular status of mineral and acid-base metabolism were evaluated in 11 males, 3-18 years after total gastrectomy (GX). In the lumbar spine, but not in the femoral neck, BMD was decreased in seven, normal in three, and falsely high in one individual. Relative to the limits of normalcy, fasting serum levels of gastrin were low, but normal for calcium, phosphorus, parathyroid hormone, calcitonin and vitamin D, while the level of total alkaline phosphatase was elevated; fasting urine pH and calcium were low, while phosphorus and net acid were high. Regression analyses revealed serum gastrin and phosphorus, and urinary net acid as possible predictors of BMD. It was concluded that over the long-term GX evokes low BMD, but not hyperparathyroidism and deranged vitamin D metabolites. Future studies may focus on gastrin, parathyroid hormone-independent hyperphosphaturia and disturbed acid-base metabolism as indicators of a new extra-cellular equilibrium of minerals.