Polymorphisms in the vitamin D receptor and risk of gout in Chinese Han male population

Association of serum 25-hydroxyvitamin D concentrations with all-cause and cause-specific mortality among individuals with gout and hyperuricemia

BACKGROUND

We aimed to probe the association of serum 25-hydroxyvitamin D [25(OH)D] concentrations with all-cause and cause-specific mortality among patients with gout and hyperuricemia (HUA).

METHODS

The study included 1169 gout patients and 7029 HUA patients from the National Health and Nutrition Examination Survey (NHANES) 2007-2018 and 2001-2018, respectively. The association between serum 25(OH)D and mortality was evaluated by Cox proportional hazard and restricted cubic spline models.

RESULTS

Among participants with gout and HUA, the weighted mean concentrations of serum 25(OH)D were 71.49 ± 30.09 nmol/L and 64.81 ± 26.92 nmol/L, respectively. Vitamin D deficiency occurred in 29.68% of gout patients and 37.83% of HUA patients. During 6783 person-years of follow-up among gout patients, 248 all-cause deaths occurred, among which 76 died from cardiovascular disease (CVD) and 49 died from cancer. 1375 HUA patients were recorded for all-cause mortality during 59,859 person-years of follow-up, including 427 CVD deaths and 232 cancer deaths. After multifactorial adjustment, per one-unit increment in natural log-transformed 25(OH)D was associated with lower risk of 55% all-cause mortality and 61% CVD mortality among gout patients, and a 45% reduced risk of cancer mortality among HUA patients. Restricted cubic splines showed a U-shaped relationship with all-cause and CVD mortality among HUA patients, with inflection points of 72.7 nmol/L and 38.0 nmol/L, respectively. The results were robust in subgroup and sensitivity analyses.

CONCLUSIONS

Serum 25(OH)D was negatively linearly correlated with mortality among gout patients, whereas U-shaped correlated with mortality in HUA patients. These results indicate that adequate vitamin D status could prevent premature death.

The rs11568820 Variant in the Promoter Region of Vitamin D Receptor Gene Is Associated with Clinical Remission in Rheumatoid Arthritis Patients Receiving Tumor Necrosis Factor Inhibitors

The vitamin D receptor (VDR), binding to the active form of the vitamin, promotes the transcription of numerous genes involved in the proliferation of immune cells, cytokine production and lymphocyte activation. It is known that vitamin D deficiency can influence the risk of developing rheumatoid arthritis (RA) or modulate its disease activity. The aim of this study was to investigate a possible association between the rs11568820 (C > T) polymorphism in the promoter region of VDR gene and the response to therapy with anti-TNF drugs in patients with RA. A total of 178 consecutive Italian patients with RA treated with anti-TNF, naïve for biological therapy, were recruited. Disease activity data were evaluated using specific indices such as DAS28, CDAI and SDAI, measured at the start of therapy and subsequently at 22, 52, 104 and 240 weeks. A statistically significant association emerged between the rs11568820 variant allele of VDR gene and failure to remission assessed by CDAI and SDAI at 52 weeks, and by DAS28, CDAI and SDAI at 104 weeks of follow-up. Furthermore, the variant allele of this polymorphism was observed more frequently in patients who did not undergo sustained remission calculated by CDAI and SDAI. The variant T allele of rs11568820 in VDR gene is associated with a reduced remission rate with anti-TNFα drugs. These data suggest the role of VDR genetic variability in the response to therapy and in the achievement of remission.

Association between Gout and Erectile Dysfunction: A Systematic Review and Meta-Analysis

Background

The aim of this systematic review and meta-analysis was to assess the possible association between gout and erectile dysfunction (ED).

Methods

Studies were identified by extensively searching EMBASE, Pubmed, CENTRAL and ISI Web of Science. Four electronic databases were searched from their inception date to the latest issue (March 2016), without language restriction. Each reviewer screened articles independently and was blinded to the findings of the other reviewer. Data was extracted in adherence to the predetermined data collection form and meta-analysis was conducted via RevMan 5.3.

Results

Five studies involving 56465 patients (mean age: 49.11 years) with gout and 155636 non-gout subjects (mean age: 48.76 years) were selected. The combination of unadjusted odds ratio (OR) showed that patients with gout were 1.44 times more likely to be diagnosed with ED when compared with control (95% confidence interval (95%CI) 1.20, 1.72). After adjustment for age and comorbidities, the heightened risk to develop ED was still present (1.18, 95%CI 1.02, 1.38). Subgroup-analysis by age showed statistically significant association of gout and ED in all age groups. However, evidence supporting a causal effect of gout on ED was insufficient.

Conclusion

The findings of this review indicated a positive association of gout and ED, but this work is hampered by the heterogeneity among included studies, to some extent. Future studies with larger community-based homogeneous population and randomized controlled trials aimed to evaluate the effect of gout treatment on ED associated outcomes are needed at this point.

Single nucleotide polymorphisms in the vitamin D pathway associating with circulating concentrations of vitamin D metabolites and non-skeletal health outcomes: Review of genetic association studies

Polymorphisms in genes encoding proteins involved in vitamin D metabolism and transport are recognised to influence vitamin D status. Syntheses of genetic association studies linking these variants to non-skeletal health outcomes are lacking. We therefore conducted a literature review to identify reports of statistically significant associations between single nucleotide polymorphisms (SNP) in 11 vitamin D pathway genes (DHCR7, CYP2R1, CYP3A4, CYP27A1, DBP, LRP2, CUB, CYP27B1, CYP24A1, VDR and RXRA) and non-bone health outcomes and circulating levels of 25-hydroxyvitamin D (25[OH]D and 1,25-dihydroxyvitamin D (1,25[OH]₂D). A total of 120 genetic association studies reported positive associations, of which 44 investigated determinants of circulating 25(OH)D and/or 1,25(OH)₂D concentrations, and 76 investigated determinants of non-skeletal health outcomes. Statistically significant associations were reported for a total of 55 SNP in the 11 genes investigated. There was limited overlap between genetic determinants of vitamin D status and those associated with non-skeletal health outcomes: polymorphisms in DBP, CYP2R1 and DHCR7 were the most frequent to be reported to associate with circulating concentrations of 25(OH)D, while polymorphisms in VDR were most commonly reported to associate with non-skeletal health outcomes, among which infectious and autoimmune diseases were the most represented.