Low Bone Mineral Density in Young Patients Newly Diagnosed with Inflammatory Bowel Disease

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.

Causal effects from inflammatory bowel disease on liver function and disease: a two-sample Mendelian randomization study

Background

Accumulating evidence has shown that patients with inflammatory bowel disease (IBD) have liver function abnormalities and are susceptible to liver diseases. However, the existence of a causal relationship between IBD and liver function or disease remains unclear.

Methods

A two-sample Mendelian randomization (MR) analysis was performed using genetic associations from publicly available genome-wide association studies (GWAS). These associations encompass ulcerative colitis (UC), Crohn's disease (CD), liver function traits, and liver disease phenotypes. The liver function traits comprised hepatic biochemistries, percent liver fat, and liver iron content from the UK Biobank. Furthermore, the liver disease phenotypes included cholelithiasis, non-alcoholic fatty liver disease (NAFLD), primary sclerosing cholangitis (PSC), and primary biliary cholangitis (PBC) in cohorts of European ancestry. The primary estimation used the inverse-variance weighted method, with GWAS of C-reactive protein (CRP) in the UK Biobank serving as a positive control outcome.

Results

Genetically predicted UC is causally associated with decreased levels of albumin (ALB) and liver iron content, while genetically predicted CD is causally associated with increased levels of alkaline phosphatase (ALP). Moreover, genetically predicted UC or CD increases the risk of PSC, and CD increases the risk of PBC. Neither UC nor CD causally increases the risk of cholelithiasis and NAFLD.

Conclusion

UC affects the levels of ALB and liver iron content, while CD affects the levels of ALP. Both UC and CD increase the risk of PSC, and CD increases the risk of PBC.

Risk Factors of Low Bone Mineral Density in Newly Diagnosed Pediatric Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract with an increasing worldwide incidence. IBD is frequently diagnosed during childhood in the adolescent period of ongoing growth and development, and it can affect patients' linear growth, puberty, nutrition, and bone health. Therefore, its treatment and monitoring are critical to prevent secondary outcomes. However, few studies have highlighted the association between pediatric IBD and skeletal outcomes in Asian populations. We aimed to identify the prevalence and risk factors for low bone mineral density (BMD) in Korean children and adolescents with newly diagnosed IBD. Patients aged 10-18 years diagnosed with either Crohn's disease (CD) or ulcerative colitis (UC) who underwent lumbar spine bone mineral density (LSBMD) and femoral bone mineral density (FBMD) analyses via dual-energy X-ray absorptiometry at the time of IBD diagnosis were included. Low BMD was considered when the age- and sex-matched BMD Z-score was <-1.0. The LSBMD and FBMD Z-scores were correlated with clinical parameters, including general characteristics, anthropometry, and IBD-associated laboratory markers. Regression analyses were performed to identify the risk factors for low BMD. Although the general characteristics between CD (n = 42) and UC (n = 9) groups did not differ, the mean Z-scores of LSBMD and FBMD of the 51 subjects were -0.11 ± 1.24 and -0.58 ± 1.38, respectively. Furthermore, 7.8% and 18% of the study subjects had LSBMD and FBMD Z-scores < -2.0, whereas more than 50% had scores of 0--1.0. Among the clinical factors, body mass index (BMI) Z-score, duration of clinical manifestations, and serum alanine aminotransferase and selenium levels were associated with LSBMD Z-scores in the final multivariate regression analyses. Odds ratios of BMI < -2.0 standard deviation for low LSBMD and FBMD Z-scores were 31.97 and 41.45, respectively. A BMI Z-score < -0.93 was determined as the best cut-off for predicting low BMD. In newly diagnosed pediatric IBD, a substantial number of children are likely to have low BMD in prior to initial treatment while lower BMI, longer duration of clinical manifestation, and higher selenium concentration could affect initial BMD status. Routine bone health surveillance from initial IBD diagnosis throughout the treatment's completion is recommended for preventing the early development of secondary osteoporosis.

Bone mineral density and its influential factors in Chinese patients with newly diagnosed Crohn's disease

OBJECTIVES

Bone loss is a common morbidity in patients with inflammatory bowel disease (IBD). Bone mineral density (BMD) measurement is recommended for IBD patients at a high risk of osteoporosis. However, there is a lack of evidence in the need of BMD measurement in patients who are young at the first disease onset. In this study we aimed to investigate the prevalence of low BMD in patients with newly diagnosed Crohn's disease (CD) at 20-50 years of age and the potential risk factors.

METHODS

A single-center, retrospective cross-sectional study was conducted. Medical records of the patients were reviewed and their demographics, clinical characteristics and laboratory test results were collected. Dual energy X-ray absorptiometry (DEXA) scan was performed for BMD measurements; low BMD was defined as Z-score or T-score <-1.0 standard deviation (SD). Univariate and multivariate logistic regression analyses were used to determine the risk factors for low BMD.

RESULTS

A total of 221 patients with CD were included; osteopenia and osteoporosis were identified in 23.1% and 8.6%, and 39.4% and 7.2% of the patients using Z-score and T-score, respectively. Female gender and a higher BMI at diagnosis were protective factors for low BMD.

CONCLUSIONS

Low BMD is common in patients with newly diagnosed CD aged 20-50 years. Female gender and a higher BMI at diagnosis might protect CD patients from bone loss. Therefore, BMD measurement and early intervention with calcium and vitamin D are recommended for these patients.

The genetically predicted causal relationship of inflammatory bowel disease with bone mineral density and osteoporosis: evidence from two-sample Mendelian randomization

Background

Many existing studies indicated that patients with inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), tend to have the risk of low total body bone mineral density (BMD), and are more likely to have osteoporosis (OS). To determine the causal relationship between IBD and bone metabolic disorders, we herein performed a two-sample Mendelian randomization analysis (TSMR) using publicly available summary statistics.

Methods

Summary statistics of total body BMD, OS and IBD were downloaded from the Open Genome-Wide Association Study (GWAS), FinnGen consortium and International Inflammatory Bowel Disease Genetics Consortium (IIBDGC). The European and East Asian populations have consisted in this Mendelian Randomization (MR) work. A range of quality control procedures were taken to select eligible instrument SNPs closely associated with total body BMD, OS and IBD. To make the conclusions more reliable, we applied five robust analytical methods, among which the inverse variance weighting (IVW) method acted as the major method. Besides, heterogeneity, pleiotropy and sensitivity were evaluated.

Results

In the European population, the genetic association of UC on total body BMD (OR=0.97, 95%CI=0.96,0.99, P<0.001) and overall IBD on total body BMD (OR=0.98, 95%CI=0.97,1.00, P=0.013) were significant, while the effect of CD on total body BMD was not significant enough (OR=0.99, 95%CI=0.98,1.00, P=0.085). All of UC, CD and overall IBD can be the genetic risk factor of having OS with pathological fracture (UC: OR=1.13, 95%CI=1.02,1.26, P=0.024, CD: OR=1.14, 95%CI=1.05,1.25, P=0.003, overall IBD: OR=1.13, 95%CI=1.02,1.24, P=0.015). In East Asian groups, only CD had a causal relationship with OS (OR=1.04, 95% CI=1.01,1.07, P=0.019).

Conclusion

Our study revealed genetically predicted associations between IBD on total body BMD and OS in European and East Asian populations. This work supplemented the results of previous retrospective studies and demonstrated the necessity of BMD monitoring in patients with IBD.

Risk Factors for Worsening of Bone Loss in Patients Newly Diagnosed with Inflammatory Bowel Disease

Background. Bone loss is common in patients with inflammatory bowel disease (IBD). The aim of the present study was to determine the prevalence of metabolic bone disease in patients newly diagnosed with IBD and to identify the risk factors for bone loss over time. Methods. We performed a retrospective, both cross-sectional and longitudinal, study to extract the risk factors of bone loss (including osteopenia and osteoporosis) in patients newly diagnosed with IBD, using dual-energy X-ray absorptiometry (DXA). Results. A total of 639 patients newly diagnosed with IBD that had at least one DXA were included in the cross-sectional study. Osteopenia and osteoporosis were diagnosed in 24.6% and 5.4% of patients, respectively. Age at diagnosis, body mass index, and serum phosphorus were identified as independent factors associated with bone loss at baseline. A total of 380 of the 639 IBD patients (including 212 CD patients and 168 UC patients) with at least a second DXA scan were included in the longitudinal study. 42.6% of the patients presented a worsening of bone loss in the follow-up study. Menopause, albumin, and use of corticosteroids were identified as independent factors associated with worsening of bone loss. Conclusions. Metabolic bone disease is common in IBD patients, and there is a significant increase in prevalence of bone loss over time. Postmenopausal female, malnourished patients, and those requiring corticosteroid treatment are at risk for persistent bone loss. Therefore, BMD measurements and early intervention with supplementation of calcium and vitamin D are recommended in IBD patients with high-risk factors.