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The fat mass (FM) and obesity-associated (FTO) gene is the first obesity-susceptibility gene identified by genome-wide association scans and confirmed in several follow-up studies. Homozygotes for the risk allele (A/A) have 1.67 times greater risk of obesity than those who do not have the allele. However, it is not known whether regular exercise-induced changes in body composition are influenced by the FTO genotype. The purpose of our study was to test whether the FTO genotype is associated with exercise-induced changes in adiposity. Body composition was derived from underwater weighing before and after a 20-week endurance training program in 481 previously sedentary white subjects of the HERITAGE Family Study. FTO single-nucleotide polymorphism (SNP) rs8050136 was genotyped using Illumina GoldenGate assay. In the sedentary state, the A/A homozygotes were significantly heavier and fatter than the heterozygotes and the C/C homozygotes in men (P = 0.004) but not in women (P = 0.331; gene-by-sex interaction P = 0.0053). The FTO genotype was associated with body fat responses to regular exercise (P < 0.005; adjusted for age, sex, and baseline value of response trait): carriers of the C allele showed three times greater FM and %body fat losses than the A/A homozygotes. The FTO genotype explained 2% of the variance in adiposity changes. Our data suggest that the FTO obesity-susceptibility genotype influences the body fat responses to regular exercise. Resistance to exercise-induced reduction in total adiposity may represent one mechanism by which the FTO A allele promotes overweight and obesity. [ABSTRACT FROM AUTHOR]

Objective. To describe the prevalence of time spent in sedentary behaviors (e.g., TV/video and computer use) among youth in the US. Methods. The National Health and Nutrition Examination Survey (2001–06) provided data to examine sedentary behavior across age groups (2–5, 6–11, and 12–15 years of age), ethnic groups (European [EA], African [AA], and Mexican American [MA]), and body mass index (BMI) categories (normal weight, overweight, obese). Results. The sample included 8 707 (50.7% boys) children aged 2 to 15 years. Seventy percent of the sample was normal weight, 18.1% was overweight, and 11.5% was obese. The total proportion of young people engaged in TV/video viewing, computer use, and total screen time ≥ 2 hours daily was 33.0%, 6.7%, and 47.3%, respectively. More boys (49.4%) than girls (45.0%); older (12–15 years: 56.0%) versus younger children (2–5 years: 35.3% and 6–11 years: 49.1%); AA (66.1%) versus EA (42.5%) and MA (46.1%); obese (58.5%) versus overweight (50.8%) versus normal weight (44.6%); and low and middle income (<$25 K: 51.4% and $25–45 K: 51.2%) versus high income (>$45 K: 42.6%) children spent ≥ 2 hours daily in screen time. Conclusion. Nearly half (47%) of US children exceed ≥ 2 hours/day of time in sedentary behavior. Further, it appears there are gender, age, ethnic, BMI-defined weight status, and income differences in exceeding ≥ 2 hours/day in sedentary behavior. These results will be useful in planning targeted interventions at those populations with a higher prevalence of sedentary behavior. [ABSTRACT FROM AUTHOR]

This article discusses findings of a study which examined the importance of lipin 1 (LPIN1) gene variation in energy and glucose metabolism. This gene variation was identified as the mutated gene in the fatty liver dystrophy mouse. Several variables that have been tested for association with LPIN1 polymorphisms include resting metabolic rate, fat oxidation, fasting plasma insulin and glucose concentration, and obesity-related phenotypes.

Regular aerobic exercise has the potential to induce several beneficial health effects, including a decrease in blood pressure level, especially in hypertensive patients and in subjects with high-normal blood pressure. However, it is also well documented that some people show more pronounced blood pressure responses to endurance training than others, despite identical training programs and similar initial blood pressure levels. This kind of variation is an example of normal biologic diversity and most likely originates from interactions with genetic factors. Data from genetic epidemiologic studies indicate that there is a genetic component that affects both resting blood pressure and blood pressure responses to acute exercise. Evidence from molecular genetic studies is scarce, but the first reports suggest that DNA sequence variation in the hypertension candidate genes, such as angiotensinogen, also modify blood pressure responses to endurance training. The current knowledge regarding the role of genetic factors in the modification of blood pressure responses to endurance training will be summarized and discussed. [ABSTRACT FROM AUTHOR]

The fat mass and obesity-associated (FTO) gene was genotyped for the participants in the Dose-Response to Exercise in postmenopausal Women (DREW) trial and analyses were performed to determine whether an FTO variant was associated with adiposity and cardiorespiratory fitness (CRF) before and after 6 months of moderate intensity exercise in white women (n = 234). The A/A homozygotes for rs8050136 had a higher BMI (kg/m2) compared to C/C homozygotes at baseline (32.8 (0.6) vs. 31.0 (0.4), respectively; P < 0.05) and at follow-up (31.9 (0.6) vs. 30.4 (0.5), respectively; P < 0.05). Weight loss occurred after exercise, but there was no significant genotype by exercise interaction over time. Exploratory analyses among women exposed to moderate intensity exercise meeting, or exceeding, the physical activity recommendation found that those homozygous A/A lost significantly more weight than the C allele carriers (−3.3 (0.7) kg vs. −1.4 (0.4) kg and −1.5 (0.5) kg, respectively; P < 0.05). CRF, defined as VO2peak (oxygen consumption), increased after exercise and the magnitude of the increase was similar for each genotype. In conclusion, women genetically predisposed to being obese experienced weight loss and CRF benefits with moderate intensity exercise, with additional weight loss observed when the women met or exceeded the physical activity recommendations. [ABSTRACT FROM AUTHOR]

Physical activity level is an important component of the total daily energy expenditure and as such contributes to body weight regulation. A body of data indicates that the level of physical activity plays a role in the risk of excessive weight gain, in weight loss programs, and particularly in the prevention of weight regain. Most studies dealing with potential gene-physical activity interaction effects use an exercise and fitness or performance paradigm as opposed to an obesity-driven model. From these studies, it is clear that there are considerable individual differences in the response to an exercise regimen and that there is a substantial familial aggregation component to the observed heterogeneity. Few studies have focused on the role of specific genes in accounting for the highly prevalent gene-exercise interaction effects. Results for specific genes have been inconsistent with few exceptions. Progress is likely to come when studies will be designed to truly address gene-exercise or physical activity interaction issues and with sample sizes that will provide adequate statistical power. [ABSTRACT FROM AUTHOR]

The sodium bicarbonate cotransporter gene (SLC4A5) has been associated with cardiovascular phenotypes in two large studies. We investigated the associations between SLC4A5 polymorphisms and cardiovascular and metabolic traits in the HERITAGE Family Study. Five single nucleotide polymorphisms (SNPs) rs1667627, rs828853, rs7571842, rs2034454 and rs6731545 were analyzed in 276 Black and 503 White healthy, sedentary subjects. In Whites, haplotypes 2 and 5, defined by SNPs rs7571842, rs2034454, and rs6731545, were associated with resting and submaximal exercise systolic blood pressure and pulse pressure (0.048>p>0.0003). In addition, oxygen consumption, CO2 production and minute ventilation during submaximal exercise showed strong associations with haplotype 2 (p<0.0009). Haplotype 2 homozygotes had lower phenotype levels than subjects with other haplotypes. Haplotype 2 explained from about 1 to 3.5% of the variance in these phenotypes. Haplotype associations were confirmed in single marker analysis. No significant associations were found in Blacks. These results in the HERITAGE Family Study confirm previous studies on cardiovascular phenotypes at rest and extend them to observations at submaximal exercise. A novel finding is the strong association between the SLC4A5 genotypes and submaximal exercise metabolic traits. [ABSTRACT FROM AUTHOR]