<p>Plausible relationship between homocysteine and obesity risk via <em>MTHFR</em> gene: a meta-analysis of 38,317 individuals implementing Mendelian randomization</p>

Abstract

Objective Numerous studies have explored the role of methylenetetrahydrofolate reductase gene ( MTHFR ) C677T polymorphism and homocysteine (Hcy) concentration in obesity, but the results are inconsistent. Hence, we performed a meta-analysis implementing Mendelian randomization approach to test the assumption that the increased Hcy concentration is plausibly related to the elevated risk of obesity. Methods Eligible studies were selected based on several inclusion and exclusion criteria. Correlations between MTHFR C677T and obesity risk, MTHFR C677T and Hcy concentration in obesity, Hcy concentration, and obesity were estimated by ORs, effect size and standard mean difference with their corresponding 95% CIs, respectively. Furthermore, Mendelian randomization analysis was performed to estimate the relationship between Hcy level and obesity. Results Consequently, this meta-analysis implemented with Mendelian randomization approach was conducted among 8,622 cases and 29,695 controls. The results indicated that MTHFR C677T is associated with an increased risk of obesity (for T vs C: OR=1.06, 95% CI=1.02–1.10; for TT vs CC: OR=1.13, 95% CI=1.03–1.24). Moreover, in obese subjects, the pooled Hcy concentration in individuals of TT genotype was 2.91 mmol/L (95% CI: 0.27–5.55) higher than that in individuals of CC genotype. Furthermore, the pooled Hcy concentration in subjects with obesity was 0.74 mmol/L (95% CI: 0.36–1.12) higher than that in controls. The evaluated plausible OR associated with obesity was 1.23 for 5 μmol/L Hcy level increase. Conclusions Through this meta-analysis, we emphasize a strong relationship between Hcy level and obesity by virtue of MTHFR C677T polymorphism.

Homocysteine level, body mass index and clinical correlates in Chinese Han patients with schizophrenia

“…BMI, as a proxy for general obesity, cannot distinguish lean mass and adipose tissue, which may also confuse the relationship between obesity and HCY. Although the mechanism was still unclear, these results suggest that the Hcy metabolic pathway may play an important role in obesity 25 . In addition, we found that Hcy level was negatively correlated with blood glucose and HDL, which is consistent with previous reports 41 that hyperhomocysteinemia (HHcy) was associated with low levels of HDL.…”

“…However, results on the relationship between BMI and Hcy levels showed conflicting data 24 . A recent meta-analysis reported that Hcy was positively correlated with obesity 25 , while a recent study demonstrated opposite results in the general population 26 . A recent cross-sectional study showed that Chinese bipolar disorder (BD) patients with hyperhomocystinemia had elevated BMI 16 .…”

Impact of weight loss predictors in severe-morbid obesity patients in the Saudi population

“…Twin family and adoption studies indicates the heritability rate of BMI is high (i.e. ;40–70%) indicating as genetic factors have the pivotal role in pathophysiology of obesity ( Fu et al, 2019 ). Heritability in terms of parental obesity is found to be important risk factor for childhood and adolescent obesity ( Danielzik et al, 2002 ).…”

Commentary: Vitamin C and Metabolic Syndrome: A Meta-Analysis of Observational Studies

“…Vegetables and fruits contain a wide range of constituents with potential impact on human health. However, the discussion focused exclusively on the potential role of vitamin C itself, with no mention of any of the other potentially beneficial constituents of vegetables and fruits, such as nitrate ( 3 ), phytochemicals ( 4 ), and folate ( 5 ). There is no mention of the possibility that the vitamin C intake/plasma concentration might be simply a marker of intake of vegetables and fruits, in which case vitamin C itself may have only a minor role in the association or, maybe, none at all.…”