Association of the MTHFR C677T polymorphism and bone mineral density in postmenopausal women: a meta-analysis

Genetic variants of MTHFR gene in relation to folic acid levels and bone mineral density in Polish patients with inflammatory bowel disease

Lower bone mineral density (BMD) constitutes a common issue in inflammatory bowel disease (IBD). Studies often explore the association between BMD and folic acid level. The presented study aimed to evaluate the impact of MTHFR gene polymorphism and folic acid levels on BMD in patients with IBDs: Crohn's disease (CD) and ulcerative colitis (UC). The study group comprised IBD patients and a healthy control group. BMD, T-score, and Z-score of the lumbar spine (L1-L4) and femoral neck (FN) were assessed using dual-energy X-ray absorptiometry. Folic acid level was determined using direct chemiluminescence, and the MTHFR 677C > T (rs1801133) and 1298A > C (rs1801131) genotyping were performed by HRMA. Our study found no significant differences in the folic acid levels between the groups. Patients with CD and UC presented a lower BMD, T-score, and Z-score of the FN and L1-L4 than the CG. UC patients who were homozygotes AA in loci c.1298A>C presented lower than controls lumbar spine L1-L4 BMD and T-score values. Regarding MTHFR 677 polymorphism, we found that IBD patients carrying CC genotype demonstrated lower than controls femoral neck Z-score, lumbar spine L1-L4 BMD, T-score and Z-score. MTHFR polymorphisms were found to have no impact on folic acid concentrations. IBD patients presented a higher risk of low BMD than the healthy controls, regardless of MTHFR 677 and 1298 genotypes. However, MTHFR polymorphism may influence on bone in IBD patients. Nevertheless, it appears essential to conduct further studies.

Influence of homocysteine and its major genetic and nutritional determinants on bone mineral density

INTRODUCTION

A potential role of hyperhomocysteinemia in bone metabolism has been considered from the observation of high prevalence of osteoporosis in subjects with homocystinuria about 50 years ago.

AIM

To examine the association of homocysteine level and its determinants Methylenetetrahydrofolate Reductase [MTHFR] C677T Polymorphism, folates and vitamin B12 levels with bone mineral density [BMD] and the prevalence of vertebral fractures [VF] on postmenopausal women.

METHODS

Through a cross-sectional study, one hundred and twenty-two healthy postmenopausal women gave their informed consent to participate in this study. Women were recruited through advertisements and mouth to ear between January 2017 and May 2017. One serum tube and one EDTA tube were collected from fasting patients. Bone mineral density was determined by a Lunar Prodigy® Vision DXA system®. Vertebral fracture [VF] assessment image was inspected visually by 2 clinicians.

RESULTS

We found that a high level of homocysteine and low vitamin B12 and folate levels are not associated with bone mineral density and are not risk factors for VF in healthy postmenopausal women. Whereas, the presence of VF was associated with the number of years since menopause and with the osteocalcin levels.

CONCLUSION

The MTHFR C677T polymorphism, the high levels of HCY, or low levels of folate and vitamin B12 would not be risk factors for osteoporosis and VF in healthy postmenopausal women.

Does Folic Acid Protect Patients with Inflammatory Bowel Disease from Complications?

Folic acid, referred to as vitamin B9, is a water-soluble substance, which participates in the synthesis of nucleic acids, amino acids, and proteins. Similarly to B12 and B6, vitamin B9 is involved in the metabolism of homocysteine, which is associated with the MTHFR gene. The human body is not able to synthesize folic acid; thus, it must be supplemented with diet. The most common consequence of folic acid deficiency is anemia; however, some studies have also demonstrated the correlation between low bone mineral density, hyperhomocysteinemia, and folic acid deficiency. Patients with inflammatory bowel disease (IBD) frequently suffer from malabsorption and avoid certain products, such as fresh fruits and vegetables, which constitute the main sources of vitamin B9. Additionally, the use of sulfasalazine by patients may result in folic acid deficiency. Therefore, IBD patients present a higher risk of folic acid deficiency and require particular supervision with regard to anemia and osteoporosis prevention, which are common consequences of IBD.

Experimental study of the effect on bone metabolism and bone histomorphometry of osteoporosis rats with birdpecking and revolving moxibustion on twelve back-shu points

The aim of the study was to explore the effect of birdpecking and revolving moxibustion on twelve back shenshu points on the bone metabolism and bone histomorphometry of osteoporosis rats. The 50 female rats of 8 months old that did not pregnant were collected and randomly divided into sham-operation group, model group, moxibustion group, moxibustion and estrogen group, and estrogen group. All the rats, except for the rats in the sham-operation group, received ovarian surgery to establish the models. After 10 days postoperatively (healing), the rats received moxibustion and estrogen therapy. According to the different groups, the rats received rat femur in vivo bone mineral density assessment at 90 days after surgery. After that, the rats were sacrificed, and then the left femoral bones were collected for bone histomorphometry test; blood was taken for bone alkaline phosphatase (BALP) testing, and urine was collected for hydroxyproline testing. The urine hydroxyproline was tested once at 24 h after ovarian surgery. At 24 h after ovarian surgery, the urine hydroxyproline in the ovariectomy group was significantly higher than that in the sham-operation group (P < 0.05), indicating that after ovarian surgery, the collagen broke down which accelerated the process of osteoporosis. After the intervention therapy with moxibustion and estrogen, the BALP, urinary hydroxyproline and femoral bone histomorphometry were comparatively analyzed, and the results showed that the intervention groups were higher than the model group (P < 0.05). But when compared with the sham-operation group, the indexes in the intervention groups were decreased, and the differences were significant (P < 0.05), indicating that intervention could only delay the incidence of osteoporosis. The Chinese traditional measure of "birdpecking and revolving moxibustion on twelve back-shu points" can effectively prevent the recession of bone metabolism of osteoporosis rats, and slow down the degeneration of bone morphology, which can be used to delay the incidence of osteoporosis.

Vitamin B12, folic acid, and bone

Vitamin B12 and folic acid deficiency are associated with a higher serum concentration of homocysteine. A high serum homocysteine is a risk factor for fractures. Both vitamins play a role in the remethylation of homocysteine to methionine. The pathophysiology from a high serum homocysteine to fractures is not completely clear, but might involve bone mineral density, bone turnover, bone blood flow, DNA methylation, and/or physical function and fall risk. Genetic variation, especially polymorphisms of the gene encoding for methylenetetrahydrofolate reductase may play a role in homocysteine metabolism and fracture risk. It is uncertain whether supplementation with vitamin B12 and folate can decrease fracture incidence. One double blind clinical trial in post-stroke patients showed that these B vitamins could decrease hip fracture incidence, but the results of further clinical trials should be awaited before a definite conclusion can be drawn.