High serum total homocysteine levels accelerate hip bone loss in healthy premenopausal women and men

Association of high-density lipoprotein, triglycerides, and homocysteine with bone mineral density in young Indian tribal women

This study investigated association between lipids and homocysteine (Hcy) with bone mineral density (BMD) in young women as opposed to previous studies on elderly women. HDL, triglyceride, and Hcy are significantly associated with BMD in young women and tobacco and alcohol consumption have no effect on this association.

PURPOSE

The present study investigates whether the association of serum lipids and homocysteine (Hcy) with bone mineral density (BMD) reported mostly in elderly population can be generalized to young or premenopausal women, consequently suggesting screening of young women with low BMD for dyslipidemia or any cardiovascular events and vice versa.

METHODS

Women (n = 293, aged 20-47 years) from Northeast India belonging to Tibeto-Burman origin were enrolled. Information about their physical and clinical attributes were collected by a structured questionnaire. Their BMDs at lumbar spine and femur were measured by dual-energy X-ray absorptiometry (DXA) and sera were profiled for lipid parameters and Hcy by auto-analyzer and ELISA, respectively. Women consuming tobacco and/or alcohol were grouped as consumers and others as non-consumers for the analysis.

RESULTS

Positive correlation of BMD with HDL (spine and femur r = 0.38, p < 0.0001) and triglyceride (spine r = 0.534, p < 0.0001; femur r = 0.423, p < 0.0001) was observed, whereas Hcy correlated negatively with BMD (spine r = - 0.189, p = 0.0026; femur r = - 0.273, p < 0.0001). LDL showed a weak negative correlation with BMD (spine r = - 0.128, p = 0.0283; femur r = - 0.199, p = 0.0006). However, after adjusting for age, BMI, and consumption, HDL, triglyceride, and Hcy continued to show significant correlation with BMD at both the sites. Logistic regression analyses indicated that HDL, triglyceride, and Hcy were significant predictors of osteopenia and osteoporosis in our study cohort; however, consumption did not contribute to its prediction.

CONCLUSION

Low levels of HDL and triglyceride and high levels of Hcy are significantly associated with osteopenia and osteoporosis in young Northeast Indian women.

Impaired skeletal health in patients with chronic atrophic gastritis

OBJECTIVE

In chronic atrophic gastritis (CAG), destruction of gastric parietal cells causes anacidity and hypergastrinemia. Use of proton pump inhibitors, which also induces gastric anacidity, is associated with increased fracture rates. Our objectives were to study possible differences in bone mineral density (BMD) and bone quality in patients with CAG compared to controls.

MATERIAL AND METHODS

We performed a cross-sectional study on 17 CAG patients aged 54 ± 13 years and 41 sex- and age-matched controls. Lumbar and femoral BMD and bone quality assessed by lumbar trabecular bone score (TBS) were measured by DXA, and bone material strength (BMS) by microindentation of the tibia. Serum bone markers (CTX, P1NP, sclerostin, osteocalcin, OPG, RANKL) were analyzed.

RESULTS

We found lower lumbar BMD Z-score (-0.324 ± 1.096 versus 0.456 ± 1.262, p = 0.030), as well as a higher frequency of osteoporosis at the lumbar spine (p = 0.046) and osteopenia at total hip (p = 0.019) in patients compared to controls. In a post hoc subgroup analysis, we observed that the differences were confined to the male patients. TBS also tended to be lower in male patients (p = 0.059), while BMS did not differ between the groups. Osteocalcin, sclerostin, OPG, and OPG/RANKL ratio were lower in patients compared to controls, while CTX and P1NP did not differ between the groups.

CONCLUSIONS

We observed lower lumbar BMD, increased frequency of osteopenia and osteoporosis in male, but not female patients with CAG. Bone markers suggest a decrease in bone formation and increased bone resorption in CAG patients compared to controls.

Association between premature ovarian failure, polymorphisms in MTHFR and MTRR genes and serum homocysteine concentration

This study investigated the association between premature ovarian failure (POF), MTHFR C677T/A1298C and MTRR A66G genotypes and serum homocysteine (Hcy) concentration. A prospective study was conducted in Chinese women, which included POF patients (n = 180) and controls (n = 195). Peripheral blood samples were used to determine MTHFR C677T/A1298C and MTRR A66G genotypes, and serum Hcy and sex hormone concentrations. Results showed that serum Hcy concentrations of POF patients were significantly higher than those of controls (P < 0.0001). In POF patients, serum Hcy concentrations were significantly correlated with oestradiol and FSH concentrations (r = -0.174, P = 0.037 and r = +0.238, P = 0.006, respectively). There were no significant differences in the distributions of MTHFR C677T/A1298C or MTRR A66G genotypes between the two groups. However, these genetic variants influenced serum Hcy concentrations in POF patients, especially for MTRR 66 AA/AG/GG genotypes, which were significantly correlated with the patients' Hcy concentrations (τ = 0.166, P = 0.033). These results suggest that serum Hcy concentrations in Chinese POF patients are increased and correlated with serum oestradiol/FSH concentrations. In conclusion, MTHFR C667T/A1298C and MTRR A66G genotypes are not associated with POF development, but they affect the patients' serum Hcy concentrations.

B-vitamin status in relation to bone mineral density in treated celiac disease patients

OBJECTIVES

Patients with celiac disease (CD) are at increased risk of osteoporosis and compromised B-vitamin status. Emerging evidence supports a beneficial role of folate and the metabolically related B-vitamins in bone health in generally healthy adults, but no previous study has investigated this in CD patients. The aim of the current study was to examine the relationship of folate, vitamins B12, B6 and B2 (riboflavin), and the related metabolite homocysteine, with bone mineral density (BMD) in CD patients.

MATERIALS AND METHODS

Of the 400 treated adult CD patients invited to participate, 110 responded and met the eligibility criteria for study participation. BMD was measured using dual energy X-ray absorptiometry scanning at the lumbar spine (L1-L4), femoral neck, and total hip sites. Biomarker status of the relevant B-vitamins and homocysteine, and dietary B-vitamin intakes, were measured.

RESULTS

The significant predictors of low BMD were increasing age (B = 0.080, p < 0.001) and decreasing weight (B = 0.072, p = 0.004), whereas no significant relationship with serum 25-hydroxyvitamin D (B = 0.093, p = 0.928) was observed. Following adjustment for these predictors, serum vitamin B12 (but no other B-vitamin biomarker) was found to be a significant determinant of BMD at the femoral neck (β = 0.416, p = 0.011) and total hip (β = 0.327, p = 0.049) in men only. No significant relationships were found between any of the B-vitamin biomarkers investigated and BMD (at any measured site) in women.

CONCLUSION

These findings add to current evidence suggesting a potential role of vitamin B12 in BMD, particularly in men, and show such a relationship for the first time in CD patients.

Effect of B vitamin (folate, B6, and B12) supplementation on osteoporotic fracture and bone turnover markers: a meta-analysis

BACKGROUND

B vitamins (including folate, B6, and B12) supplementation can effectively and easily modify high plasma homocysteine (Hcy). However, the role of Hcy in the pathogenesis of osteoporotic fracture and bone turnover is still controversial. This meta-analysis aimed to assess the impact of B vitamin supplementation on occurrence of any osteoporotic fracture and bone turnover by pooling the results of previous studies.

MATERIAL AND METHODS

Relevant randomized controlled trials (RCTs) were searched in databases. Data integration and analysis were done by using Review Manager 5.3 (the Cochrane Collaboration). The risk ratio (RR) and corresponding 95% confidence intervals (CI) of fracture (intervention vs. control) were estimated. Changes in bone turnover indicators (continuous data), weighted mean difference (WMD), and corresponding 95% (CI) were pooled for estimation.

RESULTS

Based on the results of 4 RCTs, this meta-analysis failed to identify a risk-reducing effect of daily supplementation of B vitamins on osteoporotic fracture in patients with vascular disease and with relatively normal plasma Hcy. In addition, we also did not find any positive effects of B vitamin supplementation on bone turnover.

CONCLUSIONS

B vitamin supplementation might not be effective in preventing fracture and improving bone turnover. However, the possible benefits in selective populations, such as populations with very high plasma Hcy and from regions without B vitamin fortification should be explored in the future.

HDL-Associated Paraoxonase 1 as a Bridge between Postmenopausal Osteoporosis and Cardiovascular Disease

The association of postmenopausal osteoporosis (PMOP) with both atherosclerosis and vascular/valvular calcification is well known. Recently, ample evidence has suggested a common etiologic factor, namely, reduced HDL-associated paraoxonase 1 (PON1) activity, as a causative factor in the development of PMOP and cardiovascular disease (CVD). This common etiologic factor not only contributes to atherosclerotic diseases but also to PMOP following an almost identical mechanism including dysfunctional HDL and lipid oxidation. According to recent studies, lipid oxidation might improve osteoblastic transformation of vascular cells and obstruct such transformation in bone cells. The primary objective of this current review was to summarize the evidence revealing the role of HDL-associated PON1 enzyme in PMOP. Additionally, the review aimed to address some of the subjects that need further investigation in order to define whether hyperhomocysteinemia and sensitivity to lipid oxidation may be risk factors for PMOP.

Effect of folic acid on bone metabolism: a randomized double blind clinical trial in postmenopausal osteoporotic women

BACKGROUND

In spite of several studies, the impact of homocysteine level and folic acid supplementation on bone metabolism is yet to be recognized. In this registered clinical trial (IRCT2014042217385N1), we aimed to find out the power of 6-month folic acid supplementation on homocysteine level and bone metabolism.

METHODS

Forty postmenopausal osteoporotic women (50 to 87 years) were enrolled in the study. All participants were randomized to receive folic acid 1 mg (n = 17) or placebo (n = 14). At baseline, 3 months, and finally 6 months post intervention, the level of homocysteine, vitamin B12, and bone biomarkers were measured.

RESULTS

Both groups were similar at baseline. The homocysteine decreased in both groups but statistically non-significant (P > 0.05). The changes of the serum level of vitamin B12, osteocalcin, and β cross laps were significant between groups after 6 months (P ≤ 0.05).

CONCLUSION

The trend of changes of bone biomarkers after 6 months folic acid supplementation shows that homocysteine concentration and/or folic acid supplementation have impact on the rate of bone metabolism. However, further investigations by larger sample size and differentiating age and gender are still needed to clarify the exact role of folate, homocysteine and vitamin B12.

B-vitamins and bone in health and disease: the current evidence

Osteoporosis, a metabolic skeletal disease characterised by decreased bone mass and increased fracture risk, is a growing public health problem. Among the various risk factors for osteoporosis, calcium and vitamin D have well-established protective roles, but it is likely that other nutritional factors are also implicated. This review will explore the emerging evidence supporting a role for certain B-vitamins, homocysteine and the 677 C → T polymorphism in the gene encoding the folate-metabolising enzyme methylenetetrahydrofolate reductase, in bone health and disease. The evidence, however, is not entirely consistent and as yet no clear mechanism has been defined to explain the potential link between B-vitamins and bone health. Coeliac disease, a common condition of malabsorption, induced by gluten ingestion in genetically susceptible individuals, is associated with an increased risk both of osteoporosis and inadequate B-vitamin status. Given the growing body of evidence linking low bone mineral density and/or increased fracture risk with low B-vitamin status and elevated homocysteine, optimal B-vitamin status may play an important protective role against osteoporosis in coeliac disease; to date, no trial has addressed this possible link.

Mass spectrometry evidence for formation of estrogen-homocysteine conjugates: estrogens can regulate homocysteine levels

Homocysteine (HCys), a sulfur-containing amino acid, is formed during the metabolism of methionine. An imbalance between the rate of production and the use of HCys during methionine metabolism can result in an increase in the plasma and urinary levels of HCys. HCys has been shown to be toxic to vascular endothelial cells through several pathways. Many earlier clinical studies have revealed an association between plasma HCys and cardiovascular and other diseases. In contrast, estrogens are suggested to lower the risk of cardiovascular disease. Several studies indicate that estrogen metabolites could be responsible for cardiovascular protection. It has been demonstrated that electrophilic estrogen quinones, E1(E2)-2,3-Q and E1(E2)-3,4-Q, can alkylate DNA as well as form conjugates with glutathione. I hypothesize that estrogen quinones generated in situ by oxidative enzymes, metal ions, or molecular oxygen can interact with HCys to form conjugates. This in turn could lower the levels of toxic HCys as well as quenching the reactive estrogen quinones, resulting in cardiovascular protective effects. To test the feasibility of a protective estrogen-HCys pathway, estrogen quinones were treated with HCys. Tandem mass spectrometry analysis of the assay mixture shows the formation of estrogen-HCys conjugates. Furthermore, incubation of catechol estrogens with myeloperoxidase (MPO) in the presence of HCys resulted in the formation of respective estrogen-HCys conjugates. The identities of estrogen-HCys conjugates in MPO assay extracts were confirmed by comparing them to pure synthesized estrogen-HCys standards. I propose that through conjugation estrogens could chemically regulate HCys levels; moreover these conjugates could be used as potential biomarkers in determining health.