Admixture/fine-mapping in Brazilians reveals a West African associated potential regulatory variant (rs114066381) with a strong female-specific effect on body mass and fat mass indexes

Association of adiposity evaluated by anthropometric and bioelectrical impedance analysis measures with cognitive performance in the ELSA-Brasil study

BACKGROUND

While midlife obesity is linked to cognitive decline, this association is inconsistent in older adults, possibly due to the limitations of body mass index (BMI) in accurately assessing adiposity at older ages. Most studies focused on White or Asian populations, did not include other adiposity measures besides BMI, adjusted the analyses for mediators, and did not investigate potential subgroup-specific associations. We compared the associations of adiposity measured by anthropometrical and bioelectrical impedance analysis (BIA) with cognitive performance in a diverse population, examining modifications by age, sex, and race, and investigating the mediating effects of obesity-related comorbidities.

METHODS

Cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) cohort (n = 12,636). Adiposity was evaluated using BMI, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), and body fat percentage (BFP). A composite global cognition score was derived from immediate, delayed recall, and word recognition word list, phonemic and semantic verbal fluency, and trail-making tests. Adjusted linear regression models were used to investigate associations. We included an interaction term in the regression models to verify if age, sex, and race were modifiers of these associations and used causal mediation methods to assess the mediating role of obesity-related comorbidities.

RESULTS

Among 10,725 participants [mean age (SD): 58.9 (8.6) years; 55.8% women, 54.4% White], larger WHR and WHtR were associated with worse global cognitive performance. These associations were not modified by age, sex, or race. An association of BFP with cognition was observed only in younger adults. Mediation analysis identified only indirect effects of these adiposity measures on cognitive performance and no direct effects.

CONCLUSION

WHR and WHtR were more consistently associated with cognitive performance than BMI. BIA measures of adiposity were associated with cognition only in younger adults. Obesity-related comorbidities fully mediated the associations of adiposity with cognition.

New insights from GWAS on BMI-related growth traits in a longitudinal cohort of admixed children with Native American and European ancestry

Body-mass index (BMI) is a hallmark of adiposity. In contrast with adulthood, the genetic architecture of BMI during childhood is poorly understood. The few genome-wide association studies (GWAS) on children have been performed almost exclusively in Europeans and at single ages. We performed cross-sectional and longitudinal GWAS for BMI-related traits on 904 admixed children with mostly Mapuche Native American and European ancestries. We found regulatory variants of the immune gene HLA-DQB3 strongly associated with BMI at 1.5 - 2.5 years old. A variant in the sex-determining gene DMRT1 was associated with the age at adiposity rebound (Age-AR) in girls (P = 9.8 × 10 - 9 ). BMI was significantly higher in Mapuche than in Europeans between 5.5 and 16.5 years old. Finally, Age-AR was significantly lower (P = 0.004 ) by 1.94 years and BMI at AR was significantly higher (P = 0.04 ) by 1.2 kg/m 2 , in Mapuche children compared with Europeans.

FTO and ADRB2 Genetic Polymorphisms Are Risk Factors for Earlier Excessive Gestational Weight Gain in Pregnant Women with Pregestational Diabetes Mellitus: Results of a Randomized Nutrigenetic Trial

Excessive gestational weight gain (GWG) is associated with increased risk of maternal and neonatal complications. We investigated obesity-related polymorphisms in the FTO gene (rs9939609, rs17817449) and ADRB2 (rs1042713, rs1042714) as candidate risk factors concerning excessive GWG in pregnant women with pregestational diabetes. This nutrigenetic trial, conducted in Brazil, randomly assigned 70 pregnant women to one of the groups: traditional diet (n = 41) or DASH diet (n = 29). Excessive GWG was the total weight gain above the upper limit of the recommendation, according to the Institute of Medicine guidelines. Genotyping was performed using real-time PCR. Time-to-event analysis was performed to investigate risk factors for progression to excessive GWG. Regardless the type of diet, AT carriers of rs9939609 (FTO) and AA carriers of rs1042713 (ADRB2) had higher risk of earlier exceeding GWG compared to TT (aHR 2.44; CI 95% 1.03-5.78; p = 0.04) and GG (aHR 3.91; CI 95% 1.12-13.70; p = 0.03) genotypes, respectively, as the AG carriers for FTO haplotype rs9939609:rs17817449 compared to TT carriers (aHR 1.79; CI 95% 1.04-3.06; p = 0.02).