Adiponectin Gene Variant rs266729 Interacts with Different Macronutrient Distribution of Two Different Hypocaloric Diets

Novel single nucleotide polymorphisms in gestational diabetes mellitus

The association between gestational diabetes mellitus (GDM) and single nucleotide polymorphisms (SNPs) has attracted global research attention. Exploring SNPs can help us further understand the pathogenesis of GDM, predict the risk of GDM, and guide the management of GDM patients. In this review, we summarized the studies on the association between SNPs and GDM, focusing on novel SNPs published in the last 10 years. The SNPs identified to be associated with GDM included HMG20A (rs7178572), CDKAL1 (rs7756992, rs7754840, and rs7747752), ADIPOQ (rs266729 and rs17300539), MTHFR (rs1801133), IL10 (rs3021094), CDKN2B (rs1063192), and TRPM5 (rs35197079). However, the role of SNPs in the prediction, diagnosis, treatment, and prognosis of GDM, as a polygenic disease, needs to be further explored in multiple ethnic populations.

Low-carbohydrate versus balanced-carbohydrate diets for reducing weight and cardiovascular risk

BACKGROUND

Debates on effective and safe diets for managing obesity in adults are ongoing. Low-carbohydrate weight-reducing diets (also known as 'low-carb diets') continue to be widely promoted, marketed and commercialised as being more effective for weight loss, and healthier, than 'balanced'-carbohydrate weight-reducing diets.

OBJECTIVES

To compare the effects of low-carbohydrate weight-reducing diets to weight-reducing diets with balanced ranges of carbohydrates, in relation to changes in weight and cardiovascular risk, in overweight and obese adults without and with type 2 diabetes mellitus (T2DM).

SEARCH METHODS

We searched MEDLINE (PubMed), Embase (Ovid), the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science Core Collection (Clarivate Analytics), ClinicalTrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) up to 25 June 2021, and screened reference lists of included trials and relevant systematic reviews. Language or publication restrictions were not applied.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in adults (18 years+) who were overweight or living with obesity, without or with T2DM, and without or with cardiovascular conditions or risk factors. Trials had to compare low-carbohydrate weight-reducing diets to balanced-carbohydrate (45% to 65% of total energy (TE)) weight-reducing diets, have a weight-reducing phase of 2 weeks or longer and be explicitly implemented for the primary purpose of reducing weight, with or without advice to restrict energy intake.  DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles and abstracts and full-text articles to determine eligibility; and independently extracted data, assessed risk of bias using RoB 2 and assessed the certainty of the evidence using GRADE. We stratified analyses by participants without and with T2DM, and by diets with weight-reducing phases only and those with weight-reducing phases followed by weight-maintenance phases. Primary outcomes were change in body weight (kg) and the number of participants per group with weight loss of at least 5%, assessed at short- (three months to < 12 months) and long-term (≥ 12 months) follow-up.

MAIN RESULTS

We included 61 parallel-arm RCTs that randomised 6925 participants to either low-carbohydrate or balanced-carbohydrate weight-reducing diets. All trials were conducted in high-income countries except for one in China. Most participants (n = 5118 randomised) did not have T2DM. Mean baseline weight across trials was 95 kg (range 66 to 132 kg). Participants with T2DM were older (mean 57 years, range 50 to 65) than those without T2DM (mean 45 years, range 22 to 62). Most trials included men and women (42/61; 3/19 men only; 16/19 women only), and people without baseline cardiovascular conditions, risk factors or events (36/61). Mean baseline diastolic blood pressure (DBP) and low-density lipoprotein (LDL) cholesterol across trials were within normal ranges. The longest weight-reducing phase of diets was two years in participants without and with T2DM. Evidence from studies with weight-reducing phases followed by weight-maintenance phases was limited. Most trials investigated low-carbohydrate diets (> 50 g to 150 g per day or < 45% of TE; n = 42), followed by very low (≤ 50 g per day or < 10% of TE; n = 14), and then incremental increases from very low to low (n = 5). The most common diets compared were low-carbohydrate, balanced-fat (20 to 35% of TE) and high-protein (> 20% of TE) treatment diets versus control diets balanced for the three macronutrients (24/61). In most trials (45/61) the energy prescription or approach used to restrict energy intake was similar in both groups. We assessed the overall risk of bias of outcomes across trials as predominantly high, mostly from bias due to missing outcome data. Using GRADE, we assessed the certainty of evidence as moderate to very low across outcomes.  Participants without and with T2DM lost weight when following weight-reducing phases of both diets at the short (range: 12.2 to 0.33 kg) and long term (range: 13.1 to 1.7 kg).  In overweight and obese participants without T2DM: low-carbohydrate weight-reducing diets compared to balanced-carbohydrate weight-reducing diets (weight-reducing phases only) probably result in little to no difference in change in body weight over three to 8.5 months (mean difference (MD) -1.07 kg, (95% confidence interval (CI) -1.55 to -0.59, I2 = 51%, 3286 participants, 37 RCTs, moderate-certainty evidence) and over one to two years (MD -0.93 kg, 95% CI -1.81 to -0.04, I2 = 40%, 1805 participants, 14 RCTs, moderate-certainty evidence); as well as change in DBP and LDL cholesterol over one to two years. The evidence is very uncertain about whether there is a difference in the number of participants per group with weight loss of at least 5% at one year (risk ratio (RR) 1.11, 95% CI 0.94 to 1.31, I2 = 17%, 137 participants, 2 RCTs, very low-certainty evidence).  In overweight and obese participants with T2DM: low-carbohydrate weight-reducing diets compared to balanced-carbohydrate weight-reducing diets (weight-reducing phases only) probably result in little to no difference in change in body weight over three to six months (MD -1.26 kg, 95% CI -2.44 to -0.09, I2 = 47%, 1114 participants, 14 RCTs, moderate-certainty evidence) and over one to two years (MD -0.33 kg, 95% CI -2.13 to 1.46, I2 = 10%, 813 participants, 7 RCTs, moderate-certainty evidence); as well in change in DBP, HbA1c and LDL cholesterol over 1 to 2 years. The evidence is very uncertain about whether there is a difference in the number of participants per group with weight loss of at least 5% at one to two years (RR 0.90, 95% CI 0.68 to 1.20, I2 = 0%, 106 participants, 2 RCTs, very low-certainty evidence).  Evidence on participant-reported adverse effects was limited, and we could not draw any conclusions about these.  AUTHORS' CONCLUSIONS: There is probably little to no difference in weight reduction and changes in cardiovascular risk factors up to two years' follow-up, when overweight and obese participants without and with T2DM are randomised to either low-carbohydrate or balanced-carbohydrate weight-reducing diets.

A circadian rhythm-related MTNR1B genetic variant (rs10830963) modulates glucose metabolism and insulin resistance after body weight loss secondary to biliopancreatic diversion surgery

Introduction

Objective: the rs10830963 SNP of the MTNR1B gene may be related with biochemical changes after weight loss induced by caloric restriction. We investigated the role of this SNP on biochemical parameters after biliopancreatic diversion (BPD) surgery in morbid obese subjects. Patients and methods: one hundred and fifty-four patients with morbid obesity, without diabetes mellitus type 2, were enrolled. Their biochemical and anthropometric parameters were recorded before the procedure and after one, two, and three years of follow-up. All subjects were genotyped (rs10830963) at baseline. Results: the decrease in fasting insulin levels seen after the first year (delta: -3.9 ± 1.2 mIU/L vs. -1.8 ± 1.1 mIU/L; p = 0.03), the second year (delta: -5.0 ± 0.3 mIU/L vs. -2.3 ± 0.2 mIU/L; p = 0.01) and the third year (delta: -5.1 ± 1.9 mIU/L vs. -2.8 ± 1.1 mIU/L; p = 0.02) was higher in non-G-allele carriers than in G-allele carriers. Additionally, the improvement of HOMA-IR levels at year one (delta: -0.7 ± 0.2 mIU/L vs. -0.2 ± 0.2 mIU/L; p = 0.03), year two (delta: -1.0 ± 0.3 mIU/L vs. -0.5 ± 0.2 mIU/L; p = 0.01) and year three (delta: -1.2 ± 0.3 mIU/L vs. -0.4 ± 0.2 mIU/L; p = 0.03) was also higher in non-G-allele carriers than in G-allele carriers. Finally, basal glucose levels after the first year (delta: -10.1 ± 2.4 mg/dL vs. -3.6 ± 1.8 mg/dL; p = 0.02), the second year (delta: -16.0 ± 2.3 mg/dL vs. -8.4 ± 2.2 mg/dL; p = 0.01) and the third year (delta: -17.4 ± 3.1 mg/dL vs. -8.8 ± 2.9 mg/dL; p = 0.03) were higher in non-G-allele carriers than in G-allele carriers, too. Improvements seen in comorbidities were similar in both genotype groups. Conclusion: our study showed an association of the rs10830963 MTNR1B polymorphism after massive weight loss with lower glucose response, insulin resistance, and fasting insulin levels in G-allele carriers.

Quantile-dependent expressivity of plasma adiponectin concentrations may explain its sex-specific heritability, gene-environment interactions, and genotype-specific response to postprandial lipemia

Background

"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g. adiponectin) is high or low relative to its distribution. We have previously shown that the heritability (h² ) of adiposity, lipoproteins, postprandial lipemia, pulmonary function, and coffee and alcohol consumption are quantile-specific. Whether adiponectin heritability is quantile specific remains to be determined.

Methods

Plasma adiponectin concentrations from 4,182 offspring-parent pairs and 1,662 sibships from the Framingham Heart Study were analyzed. Quantile-specific heritability from offspring-parent (β _OP,h² = 2β _OP/(1 + r_spouse)) and full-sib regression slopes (β _FS, h² = {(1 + 8r_spouse β _FS)^0.05-1}/(2r_spouse)) were robustly estimated by quantile regression with nonparametric significance assigned from 1,000 bootstrap samples.

Results

Quantile-specific h² (± SE) increased with increasing percentiles of the offspring's age- and sex-adjusted adiponectin distribution when estimated from β _OP (P _trend = 2.2 × 10^-6): 0.30 ± 0.03 at the 10th, 0.33 ± 0.04 at the 25th, 0.43 ± 0.04 at the 50th, 0.55 ± 0.05 at the 75th, and 0.57 ± 0.08 at the 90th percentile, and when estimated from β _FS (P _trend = 7.6 × 10^-7): 0.42 ± 0.03 at the 10th, 0.44 ± 0.04 at the 25th, 0.56 ± 0.05 at the 50th, 0.73 ± 0.08 at the 75th, and 0.79 ± 0.11 at the 90th percentile. Consistent with quantile-dependent expressivity, adiponectin's: (1) heritability was greater in women in accordance with their higher adiponection concentrations; (2) relationships to ADIPOQ polymorphisms were modified by adiposity in accordance with its adiponectin-lowering effect; (3) response to rosiglitazone was predicted by the 45T> G ADIPOQ polymorphism; (4) difference by ADIPOQ haplotypes increased linearly with increasing postprandial adiponectin concentrations.

Conclusion

Adiponectin heritability is quantile dependent, which may explain sex-specific heritability, gene-environment and gene-drug interactions, and postprandial response by haplotypes.

ADIPQ gene polymorphism rs266729 (-11377 C>G) and metabolic syndrome risk in a Mexican population of western Mexico

Introduction

Introduction: obesity often leads to deregulation and disrupting of the function of adipokines, which leads to various altered conditions, including metabolic syndrome (MetS). Adiponectin is one of the main adipokines secreted by adipocytes. The ADIPQ gene polymorphism rs266729 (-11377 C>G) is significantly associated with metabolic alterations related to obesity in different populations. Mexico has a high prevalence of obesity and risk factors associated with MetS. We investigated the association of the ADIPQ gene polymorphism rs266729 (-11377 C>G) with MetS in a Mexican population of western Mexico. Methods: a total of 101 MetS patients and 70 unrelated healthy subjects were genotyped for ADIPQ polymorphism rs266729 using the restriction fragment length polymorphism method. Results: we found a higher frequency of the minor allele G in MetS patients, as compared to that observed in the control group (OR = 2.17; 95 % CI, 1.26-3.70; p = 0.003). Also, the GG genotype was significantly associated with MetS risk under codominant (OR = 4.0; 95 % CI, 1.32-11.71; p = 0.014), dominant (OR = 2.16; 95 % CI, 1.12-4.03; p = 0.018), and recessive (OR = 3.33; 95 % CI, 1.14-9.45; p = 0.033) genetic models. Conclusion: our findings suggest that the minor allele G in the ADIPQ gene polymorphism rs266729 constitutes a risk factor for the development of MetS in a Mexican population of western Mexico.