Genetic determinants of cardiometabolic risk factors in rural families in Brazil.

OBJECTIVES: The purpose of this study was to estimate the heritability of genetic and environmental correlations between cardiometabolic risk factors in extended pedigrees. METHODS: The Jequitinhonha Community Family Study Cohort (JCFSC) consists of individuals aged ≥18 years living in rural villages. Family pedigrees were constructed of the cohort. The following data were collected: demographic and socioeconomic status, lifestyle variables, anthropometrics, and lipid traits. RESULTS: The JCFSC consists of 931 individuals distributed into 69 pedigrees with 4,907 members in total. The heritabilities were 0.47 for total cholesterol (TC), 0.44 for triglycerides (TG) and 0.42 for high-density lipoprotein cholesterol (HDLc), 0.49 for metabolic syndrome, approximately 0.60 for anthropometric traits and 0.30 for blood pressure/hypertension. Significant genetic correlations (ρg ) were found mainly between TG and TC (ρg = 0.58) and hypertension and TG (ρg = 0.52). Systolic blood pressure (SBP) was correlated with TG (ρg = 0.39) and HDLc (ρg = -0.30). Diastolic blood pressures correlated with TG (ρg =0.56) and TC (ρg =0.30). Genetic correlations were also found between anthropometric traits, including: body mass index (BMI) and TG (ρg =0.34), waist circumference (WC) and TG (ρg =0.42), and WC and HDLc (ρg =-0.33). Household effects were found for HDLc (c(2) = 0.19), SBP (c(2) = 0.14) and Hypertension (c(2) = 0.14). CONCLUSIONS: To some phenotypes, including lipids, hypertension, blood pressure, and anthropometric traits, genetic contribution is important in the determination of cardiometabolic risk factors. This study provides a foundation for future studies. These will mainly focus on rare variants that could describe the genetic mechanisms influencing cardiometabolic risk. Am. J. Hum. Biol. 28:619-626, 2016. © 2016 Wiley Periodicals, Inc.

Heritability of phenotypes associated with glucose homeostasis and adiposity in a rural area of Brazil.

We aimed to estimate the heritability and genetic correlation between glucose homeostasis and adiposity traits in a population in a rural community in Brazil. The Jequitinhonha Community Family Study cohort consists of subjects aged ≥18 years residing in rural areas in Brazil. The data on the following traits were assembled for 280 individuals (51.7% women): body mass index (BMI), body fat percentage, waist and mid-upper arm circumferences, triceps skinfold, conicity index, insulin, glucose, high-density lipoprotein cholesterol (HDLc), triglycerides and C-reactive protein. Extended pedigrees were constructed up to the third generation of individuals using the data management software PEDSYS. The heritability and genetic correlations were estimated using a variance component method. The age- and sex-adjusted heritability values estimated for insulin (h(2) = 52%), glucose (h(2) = 51%), HDLc (h(2) = 58%), and waist circumference (WC; h(2) = 49%) were high. Significantly adjusted genetic correlations were observed between insulin paired with each of the following phenotypes; (BMI; ρg = 0.48), WC (ρg = 0.47) and HDLc (ρg = -0.47). The homeostasis model assessment of insulin resistance (HOMA-IR) was genetically correlated with BMI (ρg = 0.53) and HDLc (ρg = -0.58). The adjusted genetic correlations between traits were consistently higher compared with the environmental correlations. In conclusion, glucose metabolism and adiposity traits are highly heritable and share common genetic effects with body adiposity traits.

Physical activity is associated with malignant and benign breast diseases in low-income Brazilian women.

We compared the relationships among percentage of body fat (%BF) and physical activity with breast cancer (BC) and benign breast diseases (BBD) in low-income Brazilian women. A case-control study including 106 incident BC cases, 178 incident BBD cases, and 181 control women recruited from a public hospital-based screening center was conducted. Logistic regression models showed that sedentary women have a higher odds of developing BC in the age adjusted model [odds ratio (OR) = 2.39, 95% confidence interval (CI) 1.43-3.99]. After adjusting for hormonal-related risk factors and family history of breast cancer (OR = 2.94, 95% CI 1.50-5.79) and also for the % BF (OR = 2.71, 95% CI 1.36-5.37) the odds remained high. Independent of the adjustments made, %BF did not affect the odds for developing BC. When the same models were tested for women with BBD, we found a significant association with sedentary lifestyle in all models tested, with an OR = 3.03 (95% CI 1.69-5.42) in the fully adjusted model. In the same way, in the fully adjusted model %BF was significantly associated to risk for BBD (OR = 0.54, 95% CI 0.30-0.98). Similar to results found in other populations, our data suggest that physical activity is an important, independent protective factor for the risk of developing BC and BBD in low-income women from an admixed population.