Risk variants of obesity associated genes demonstrate BMI raising effect in a large cohort

Genetic variants in the MC4R gene and risk of obesity/overweight: A systematic review and meta-analysis

AIM

Obesity is a significant health issue worldwide, progressing due to genetic factors and lifestyle. Melanocortin 4 receptor (MC4R) gene polymorphisms have been identified as a cause of overweight and obesity risk. The aim of this study was a comprehensive assessment of MC4R polymorphism effects on overweight/obesity risk.

METHODS

All retrieved literature from PubMed, Web of Science and Scopus according to PRISMA guidelines up to June 2022 was reviewed. Inclusion criteria are restricted to English-language, human case-control/cohort studies with genotype distributions of MC4R polymorphisms and their association with obesity and overweight in any geographic regions and age. The heterogeneity using the I-squared statistic (I2), the Q-test and Prediction Interval (PI) and publication bias using Begg's and Egger's tests were examined, and the pooled odds ratios in different genetic models were estimated using a random effect model. Subgroup analysis was performed by the geographic regions and age groups. Risk of bias for individual studies was not assessed. The review is limited by restricted racial diversity and exclusion of environmental factors, incomplete data and limited access to certain articles. This work received no specific funding, and the review was not prospectively registered.

RESULTS

In our study, 39 eligible studies with 43 697 overweight and obese cases and 52 272 normal weights were included. In mixed-age populations, rs17700633, rs17782313, rs11872992, rs12970134, rs2229616 and rs571312 were evaluated. The remarkable association was seen by rs17782313 and rs12970134 in the Homozygous model (OR = 1.73; 95% CI: 1.51, 1.98 and 1.74; 95% CI: 1.29; 2.35, respectively). In addition, rs17782313 and rs12970134 were found to be more strongly linked to overweight and obesity in Asian and European population groups, as determined by a subgroup analysis of the geographic regions.

CONCLUSION

The present study confirms the high association of rs17782313 and rs12970134 with obesity and overweight in all age groups and geographic regions. However, further functional studies and high-population research on other MC4R SNPs must validate their role.

Distinct Roles of Common Genetic Variants and Their Contributions to Diabetes: MODY and Uncontrolled T2DM

Type 2 diabetes mellitus (T2DM) encompasses a range of clinical manifestations, with uncontrolled diabetes leading to progressive or irreversible damage to various organs. Numerous genes associated with monogenic diabetes, exhibiting classical patterns of inheritance (autosomal dominant or recessive), have been identified. Additionally, genes involved in complex diabetes, which interact with environmental factors to trigger the disease, have also been discovered. These genetic findings have raised hopes that genetic testing could enhance diagnostics, disease surveillance, treatment selection, and family counseling. However, the accurate interpretation of genetic data remains a significant challenge, as variants may not always be definitively classified as either benign or pathogenic. Research to date, however, indicates that periodic reevaluation of genetic variants in diabetes has led to more consistent findings, with biases being steadily eliminated. This has improved the interpretation of variants across diverse ethnicities. Clinical studies suggest that genetic risk information may motivate patients to adopt behaviors that promote the prevention or management of T2DM. Given that the clinical features of certain monogenic diabetes types overlap with T2DM, and considering the significant role of genetic variants in diabetes, healthcare providers caring for prediabetic patients should consider genetic testing as part of the diagnostic process. This review summarizes current knowledge of the most common genetic variants associated with T2DM, explores novel therapeutic targets, and discusses recent advancements in the pharmaceutical management of uncontrolled T2DM.

The accuracy of anthropometric indices in detecting hypertension in Sudanese adults: a cross-sectional study

BACKGROUND

Hypertension is an increasing health problem; hence, efforts have been made to promote the disease's early detection and modify prognoses. We aim to evaluate the accuracy of body mass index (BMI), waist circumference (WC), and waist-height ratio (WHtR) in detecting hypertension among adults in Northern Sudan.

METHODS

Adults were recruited for a multi-stage sampling survey in Northern Sudan. Sociodemographic and anthropometric index (BMI, WC, and WHtR) information were collected. A receiver operating characteristic (ROC) curve with its area under the curve (AUC) was obtained, and a multivariate binary analysis was performed.

RESULTS

Of the 301 included adults, 113 (37.5%) were females and 188 (62.5%) were males. The median (interquartile range, IQR) age was 45.0 (32.0‒59.0) years. The median (IQR) of BMI, WC, and WHtR was 25.6 (21.9‒29.7) kg/m2, 83.0 (73.0‒94.8) cm, and 0.51 (0.43‒0.58), respectively; these values were significantly higher in adults with hypertension compared with adults without hypertension. A total of 166 (55.1%) adults had hypertension. BMI (AUC = 0.69 at the cutoff 22.5 kg/m2, sensitivity = 0.89, specificity = 0.53, YI = 0.35) and WHtR for both males and females (AUC = 0.68 at the cutoff 0.48, sensitivity = 0.75, specificity = 0.60, YI = 0.35) were more accurate than WC (AUC = 0.66 at the cutoff 77.5 cm, sensitivity = 0. 77, specificity = 0.56, YI = 0.33). The multivariate binary analysis revealed that being female (adjusted odds ratio [AOR] = 2.23, 95.0% CI = 1.25‒3.97), having increased age (AOR = 1.04, 95% CI = 1.02‒1.05), and having a higher BMI (AOR = 1.10, 95% CI = 1.04‒1.16) were associated with hypertension.

CONCLUSION

BMI, WC, and WHtR showed moderate predictive power, suggesting that these indices have a limited role in diagnosing hypertension at the individual level and are more appropriate for population screening than for individual diagnosis. BMI performs better than WC in terms of hypertension detection.

Single nucleotide polymorphisms (SNPs) that are associated with obesity and type 2 diabetes among Asians: a systematic review and meta-analysis

Single nucleotide polymorphisms (SNPs) could increase the susceptibility of individuals to develop obesity and type 2 diabetes (T2DM). Obesity and T2DM are closely related pathophysiologically, thus similar SNPs could mediate both these diseases, but this is rarely reported. Furthermore, limited studies have been performed to summarize SNP data in the Asian population compared to the Western population. In this study, we aimed to summarize SNPs that are associated with the development of obesity and T2DM among Asian populations. We searched six literature databases and Review Manager (RevMan) was used for meta-analysis. The pooled odds ratios (ORs) and 95% CIs were calculated with a random effects model for the heterogeneity among studies. The pooled analysis showed that rs9939609 (FTO gene) and rs17782313 and rs571312 (MC4R gene) are associated with obesity with an odd ratio (OR) of 1.37, 1.36 and 1.29 respectively. For T2DM, five SNPs, rs7903146 and rs12255372 (TCF7L2 gene), rs13266634 and rs11558471 (SLC30A8 gene) and rs2283228 (KCNQ1 gene) have also shown strong associations with T2DM at OR of 1.64, 1.61, 1.22, 1.29 and 1.60 respectively. This data could be used to develop a gene screening panel for assessing obesity and T2DM susceptibility.

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of type 2 diabetes mellitus and dyslipidemia, but not coronary artery disease in a Chinese Han population

Background

Relationships of the polymorphisms in fat mass and obesity-associated gene (FTO) and peroxisome proliferator-activated receptor delta gene (PPARD) with metabolic-related diseases remain to be clarified.

Methods

One thousand three hundred and eighty-one subjects were enrolled. Metabolic-related diseases including obesity, dyslipidemia, hyperhomocysteinemia, hyperuricemia, hypertension, type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) were defined based on diagnostic criteria. FTO rs9939609 and rs17817449, and PPARD rs2016520 and rs2267668 polymorphisms were genotyped by using polymerase chain reaction-restricted fragment length polymorphism method.

Results

Patients with T2DM or dyslipidemia had a higher frequency of AA, AT or AA + AT genotypes as well as A allele of FTO rs9939609 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.04 for all). Patients with T2DM or dyslipidemia had a higher frequency of GG, GT or GG + GT genotypes as well as G allele of FTO rs17817449 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.03 for all). Multivariate logistic regression analyses showed that FTO rs9939609 and rs17817449 polymorphisms were independently associated with T2DM as well as dyslipidemia after adjustment for age, sex, smoking and other metabolic diseases. FTO rs9939609 and rs17817449 polymorphisms were not associated with obesity, hyperhomocysteinemia, hyperuricemia, hypertension and CAD. Obese or T2DM carriers of the AA or AT genotype of the FTO rs9939609 polymorphism had a higher prevalence of dyslipidemia compared to non-obese or non-T2DM carriers of the AA or AT genotype (P = 0.03 for both). Among the carriers of GG or GT genotype of the FTO rs17817449 polymorphism, the prevalence of dyslipidemia in obese patients was higher than that in non-obese subjects (P < 0.01). PPARD rs2016520 and rs2267668 polymorphisms were not correlated with any of the metabolic-related diseases in the study population.

Conclusion

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of T2DM and dyslipidemia, and the risk is further increased among obese individuals. PPARD rs2016520 and rs2267668 polymorphisms are not associated with metabolic-related diseases.