Role of metabolic syndrome and its components as mediators of the genetic effect on type 2 diabetes: A family-based study in China

Healthy Lifestyles Modify the Association of Melatonin Receptor 1B Gene and Ischemic Stroke: A Family-Based Cohort Study in Northern China

Limited research has reported the association between MTNR1B gene polymorphisms and ischemic stroke (IS), and there is insufficient evidence on whether adopting a healthy lifestyle can mitigate genetic risks in this context. This study aimed to investigate the associations between MTNR1B gene variants (rs10830963 and rs1387153) and IS, examining the potential effect of gene-lifestyle interactions on IS risk. Conducted in northern China, this family-based cohort study involved 5116 initially IS-free subjects. Genotype data for rs10830963 and rs1387153 in MTNR1B were collected. Eight modifiable lifestyle factors, including body mass index (BMI), smoking, alcohol consumption, dietary habits, physical activity, sedentary time, sleep duration, and chronotype, were considered in calculating healthy lifestyle scores. Multilevel Cox models were used to examine the associations between MTNR1B variants and IS. Participants carrying the rs10830963-G and rs1387153-T alleles exhibited an elevated IS risk. Each additional rs10830963-G allele and rs1387153-T allele increased the IS risk by 36% (HR = 1.36, 95% CI, 1.12-1.65) and 32% (HR = 1.32, 95% CI, 1.09-1.60), respectively. Participants were stratified into low, medium, and high healthy lifestyle score groups (1537, 2188, and 1391 participants, respectively). Genetic-lifestyle interactions were observed for rs10830963 and rs1387153 (p for interaction < 0.001). Notably, as the healthy lifestyle score increased, the effect of MTNR1B gene variants on IS risk diminished (p for trend < 0.001). This study underscores the association between the MTNR1B gene and IS, emphasizing that adherence to a healthy lifestyle can mitigate the genetic predisposition to IS.

Relationship Between the Single Nucleotide Polymorphism rs11558471 in the SLC30A8/ZnT8 Gene and Cardiometabolic Markers in Postmenopausal Women

Postmenopausal women have more risk factors for metabolic syndrome, and genetic alterations in SLC30A8 (zinc transporter 8 [ZnT8]) are directly related to these factors. Our aim was to assess the relationship of the single nucleotide polymorphism (SNP) rs11558471 in the SLC30A8/ZnT8 gene with cardiometabolic markers in postmenopausal women. This cross-sectional study included 53 postmenopausal women divided into two groups according to the SNP genotype (AG + GG [n = 25] and AA [n = 28]). Anthropometric, dietary, and biochemical (glycemic, lipidic, hepatic, renal, and hormonal markers) variables were evaluated and compared between groups. No differences in glycemic, hepatic, renal, and hormonal markers were found between groups. However, the group with the polymorphic allele (AG + GG) had a better lipid profile than non-carriers (total cholesterol, p = 0.041; low-density lipoprotein cholesterol [LDL-c], p = 0.035; non-high-density lipoprotein cholesterol [non-HDL-c], p = 0.043). Logistic regression showed that the group with polymorphic allele had lower chances of increasing levels of LDL-c (odds ratio [OR] = 0.225, p = 0.012) and non-HDL-c (OR = 0.316, p = 0.045). After adjusting for age, body mass index, physical activity, and use of diabetes and dyslipidemia drugs, only LDL-c remained associated (OR = 0.218; p = 0.017). The variant allele of SNP rs11558471 in the SLC30A8 gene was associated with better LDL-c levels, which helps reduce the risks for cardiovascular diseases in postmenopausal women.

Impaired Melatonin Secretion, Oxidative Stress and Metabolic Syndrome in Night Shift Work

Metabolic syndrome has been associated in many studies with working in shifts. Even if the mechanistic details are not fully understood, forced sleep deprivation and exposure to light, as happens during night shifts, or irregular schedules with late or very early onset of the working program, lead to a sleep-wake rhythm misalignment, metabolic dysregulation and oxidative stress. The cyclic melatonin secretion is regulated by the hypothalamic suprachiasmatic nuclei and light exposure. At a central level, melatonin promotes sleep and inhibits wake-signals. Beside this role, melatonin acts as an antioxidant and influences the functionality of the cardiovascular system and of different metabolic processes. This review presents data about the influence of night shifts on melatonin secretion and oxidative stress. Assembling data from epidemiological, experimental and clinical studies contributes to a better understanding of the pathological links between chronodisruption and the metabolic syndrome related to working in shifts.

Association of Metabolic Syndrome With Prevalence of Obstructive Sleep Apnea and Remission After Sleeve Gastrectomy

Obesity is an important risk factor for metabolic syndrome and obstructive sleep apnea (OSA). Bariatric surgery has been shown to effectively reduce weight and obesity-related comorbidities. However, the prevalence and severity of OSA in obese patients with different baseline metabolic states and the improvements of OSA after bariatric surgery remain unknown. The main aims of this study were to ascertain the prevalence of OSA in young Chinese obese patients with different metabolic states and to evaluate their respective OSA remission after laparoscopic sleeve gastrectomy. We first performed a cross-sectional study involving 123 metabolically healthy obese patients and 200 metabolically unhealthy obese patients (who had the same age and BMI ranges) to estimate the prevalence of OSA at baseline. Then we performed a retrospective study, which was registered at ClinicalTrials.gov (ref. NCT02653430) of 67 patients who underwent laparoscopic sleeve gastrectomy to evaluate the remission of OSA. Metabolically healthy and unhealthy obese patients had similar apnea-hypopnea index levels (16.6 ± 22.0 vs. 16.7 ± 18.7 events/h, P = 0.512) and prevalence of OSA (66.7% vs. 69.0%, P = 0.662). Male sex, age, waist circumference and lower liver-to-spleen ratio were independent risk factors for OSA. After laparoscopic sleeve gastrectomy, no difference was found in the decrease in body mass index (BMI) change (10.8 ± 4.8 vs. 10.8 ± 3.0 kg/m², P = 0.996) or the decrease in the apnea-hypopnea index (18.9 ± 24.6 vs. 17.0 ± 24.0 events/h, P = 0.800). The remission of moderate-to-severe OSA was observed in the MHO (36.3%; 54.5-18.2%, P = 0.125) and MUO (32.2%; 66.1-33.9%, P = 0.001) patients. These results suggest that, in patients with obesity, metabolic syndrome does not add extra risk for the prevalence or severity of OSA. Both metabolically healthy and unhealthy obese patients could benefit equally from laparoscopic sleeve gastrectomy in terms of weight loss and obstructive sleep apnea remission.