Background: Recent genome wide association studies (GWAS) and previous positional linkage studies have identified more than 50 single nucleotide polymorphisms (SNPs) associated with obesity, mostly in Europeans. We aimed to assess the contribution of some of these SNPs to obesity risk and to the variation of related metabolic traits, in Mexican children. Methods: The association of six European obesity-related SNPs in or near FTO, NPC1, ENPP1, NEGR1, GNPDA2 and MC4R genes with risk of obesity was tested in 1,463 school-aged Mexican children (N _cases = 514; N _controls = 949). We also assessed effects of these SNPs on the variation of body mass index (BMI), fasting serum insulin levels, fasting plasma glucose levels, total cholesterol and triglyceride levels, in a subset of 1,171 nonobese Mexican children. Results: We found a significant effect of GNPDA2 rs10938397 on risk of obesity (odds ratio [OR] = 1.30; P = 1.34 × 10^-3). Furthermore, we found nominal associations between obesity risk or BMI variation and the following SNPs: ENPP1 rs7754561, MC4R rs17782313 and NEGR1 rs2815752. Importantly, the at-risk alleles of both MC4R rs17782313 and NPC1 rs1805081 showed significant effect on increased fasting glucose levels (β = 0.36 mmol/L; P = 1.47 × 10^-3) and decreased fasting serum insulin levels (β = −0.10 μU/mL; P = 1.21 × 10^-3), respectively. Conclusion: Our present results suggest that some obesity-associated SNPs previously reported in Europeans also associate with risk of obesity, or metabolic quantitative traits, in Mexican children. Importantly, we found new associations between MC4R and fasting glucose levels, and between NPC1 and fasting insulin levels.

Objective: Several cutoff points of the homeostasis model assessment of insulin resistance (HOMA-IR; varying from 2.5 to 4.0) have been suggested for diagnosing IR in youth. In this study, we determined the distribution of the HOMA-IR in Mexican children and adolescents.Design and methods: A total of 6132 children and adolescents from San Luis Potosi, León, Queretaro, and Durango, which are cities in central and northern Mexico, were enrolled in a population-based cross-sectional study. Eligible participants were apparently healthy children and adolescents aged 6–18 years. Pregnancy and the presence of chronic illnesses were exclusion criteria.Results: A total of 3701 (60.3%) girls and 2431 (39.7%) boys were included in this study. In the overall population, the mean body mass index, insulin levels, and fasting glucose levels were 21.8±1.3 kg/m², 7.1±3.2 μU/ml, and 86.2±10.0 mg/dl respectively. The concentrations of insulin and fasting glucose gradually increased from 6 to 12 years of age, whereas the concentrations tended to plateau in the 13- to 18-year-old population. The absolute mean of the HOMA-IR was 2.89±0.7. The HOMA-IR gradually increased with age and reached a plateau at 13 years of age.Conclusions: Because the insulin concentrations, glucose levels, and HOMA-IR exhibited a gradual increase with age that was not related to obesity, our results suggested that the evaluation of IR in children should be based on percentiles of the HOMA-IR rather than a dichotomous value derived from a single cutoff point.

Background: Peripheral arterial disease (PAD) is an important cardiovascular disorder of the peripheral arteries. Chronic infections, such as periodontitis, may play an important role in the etiology and pathophysiology of PAD and other cardiovascular conditions. Recently, Streptococcus mutans has been found with high frequency in atheromatous plaques. The aim of this study is to evaluate the possible clinical and microbiologic association between PAD and periodontitis and dental caries.Methods: Thirty patients with PAD and 30 control individuals were selected. PAD and its severity were established by the use of the ankle‐branchial index (ABI). Clinical attachment loss (AL); probing depth; decayed, missing, and filled teeth (DMFT) index; and C‐reactive protein (CRP) levels were evaluated. The presence of bacterial DNA from Streptococcus mutans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Treponema denticola, and Aggregatibacter actinomycetemcomitans was identified by polymerase chain reaction in subgingival biofilm and serum.Results: Patients with ≥30% AL ≥ 4 mm had six‐fold increased risk of having PAD (odds ratio = 8.18; 95% confidence interval = 1.21 to 35.23; P = 0.031). There was statistical difference in the CRP (P = 0.0413) and DMFT index (P = 0.0002), with elevated number of missing teeth (P = 0.0459) in the PAD group compared with the control group. There were no significant differences in the frequency of bacteria in serum and subgingival plaque.Conclusion: There was a positive relationship between periodontitis based on AL and PAD determined by the ABI (odds ratio = 8.18).

To determine whether the association between family history of diabetes (FHD) and impaired fasting glucose (IFG) is independent of body mass index (BMI) in children and adolescents. In all 443 (11.9%) children and adolescents with FHD, and 3280 (88.1%) without FHD were enrolled in a population-based cross-sectional study. Eligible subjects to participate were apparently healthy children and adolescents aged 7-15 yr from Middle and Northern Mexico. Obesity was defined by age- and gender-specific BMI >or= 95th percentile. FHD was defined as positive if at least one first degree relative had diabetes. The IFG was defined by fasting plasma glucose >or= 100 mg/dL and < 126 mg/dL. IFG was identified in 390 (88.0%) and 62 (1.9%) children and adolescents with and without FHD, respectively. In the group with positive FHD, IFG was diagnosed in 146 (37.4%), 79 (20.2%), and 165 (42.3%) children and adolescents who were obese, overweight, and normal-weight, respectively. On the other hand, in the group without FHD, IFG was identified in 21 (33.9%), 14 (22.6%), and 27 (43.5%) children and adolescents who were obese, overweight, and normal-weight, respectively. In the overall population, the age-, sex-, and BMI-adjusted logistic regression analysis showed a strong and independent association between FHD and IFG [odds ratio (OR) -11.7; 95% CI 9.5-21.2]. This association remained strong for girls and boys in a subsequent analysis stratified for BMI category. The presence of FHD in a first degree relative is associated with IFG, even in the absence of obesity.