Effect of Chronic Athletic Activity on Brown Fat in Young Women

Background: The effect of chronic exercise activity on brown adipose tissue (BAT) is not clear, with some studies showing positive and others showing negative associations. Chronic exercise is associated with increased resting energy expenditure (REE) secondary to increased lean mass and a probable increase in BAT. Many athletes are in a state of relative energy deficit suggested by lower fat mass and hypothalamic amenorrhea. States of severe energy deficit such as anorexia nervosa are associated with reduced BAT. There are no data regarding the impact of chronic exercise activity on BAT volume or activity in young women and it is unclear whether relative energy deficiency modifies the effects of exercise on BAT. Purpose We assessed cold induced BAT volume and activity in young female athletes compared with non-athletes, and further evaluated associations of BAT with measures of REE, body composition and menstrual status. Methods: The protocol was approved by our Institutional Review Board. Written informed consent was obtained from all participants prior to study initiation. This was a cross-sectional study of 24 women (16 athletes and8 non-athletes) between 18–25 years of age. Athletes were either oligo-amenorrheic (n = 8) or eumenorrheic (n = 8).We used PET/CT scans to determine cold induced BAT activity, VMAX Encore 29 metabolic cart to obtain measures of REE, and DXA for body composition. Results: Athletes and non-athletes did not differ for age or BMI. Compared with non-athletes, athletes had lower percent body fat (p = 0.002), higher percent lean mass (p = 0.01) and trended higher in REE (p = 0.09). BAT volume and activity in athletes trended lower than in non-athletes (p = 0.06; p = 0.07, respectively). We found negative associations of BAT activity with duration of amenorrhea (r = -0.46, p = 0.02).BAT volume correlated inversely with lean mass (r = -0.46, p = 0.02), and positively with percent body fat, irisin and thyroid hormones. Conclusions: Our study shows a trend for lower BAT in young female athletes compared with non-athletes, and shows associations of brown fat with menstrual status and body composition. Brown fat may undergo adaptive reductions with increasing energy deficit

Comparing Outcomes of Two Types of Bariatric Surgery in an Adolescent Obese Population: Roux-en-Y Gastric Bypass vs. Sleeve Gastrectomy

Background: Obesity is prevalent among adolescents and is associated with serious health consequences. Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) are bariatric procedures that cause significant weight loss in adults and are increasingly being performed in adolescents with morbid obesity. Data comparing outcomes of RYGB vs. SG in this age-group are scarce. This study aims to compare short-term (1–6 months) and longer-term (7–18 months) body mass index (BMI) and biochemical outcomes following RYGB and SG in adolescents/young adults. Methods: A retrospective study using data extracted from medical records of patients 16–21 years who underwent RYGB or SG between 2012 and 2014 at a tertiary care academic medical center. Results: Forty-six patients were included in this study: 24 underwent RYGB and 22 underwent SG. Groups did not differ for baseline age, sex, race, or BMI. BMI reductions were significant at 1–6 months and 7–18 months within groups (p < 0.0001), but did not differ by surgery type (p = 0.65 and 0.09, for 1–6 months and 7–18 months, respectively). Over 7–18 months, within-group improvement in low-density lipoprotein (LDL) (−24 ± 6 in RYGB, p = 0.003, vs. −7 ± 9 mg/dl in SG, p = 0.50) and non-high-density lipoprotein (non-HDL) cholesterol (−23 ± 8 in RYGB, p = 0.02, vs. −12 ± 7 in SG, p = 0.18) appeared to be of greater magnitude following RYGB. However, differences between groups did not reach statistical significance. When divided by non-alcoholic steatohepatitis stages (NASH), patients with Stage II–III NASH had greater reductions in alanine aminotransferase levels vs. those with Stage 0–I NASH (−45 ± 18 vs. −9 ± 3, p = 0.01) after 7–18 months. RYGB and SG groups did not differ for the magnitude of post-surgical changes in liver enzymes. Conclusion: RYGB and SG did not differ for the magnitude of BMI reduction across groups, though changes trended higher following RYGB. Further prospective studies are needed to confirm these findings

Correction: Effect of Chronic Athletic Activity on Brown Fat in Young Women.

[This corrects the article DOI: 10.1371/journal.pone.0156353.]

Associations of Brown Fat with Clinical and Biochemical Characteristics.

<p>Associations of Brown Fat with Clinical and Biochemical Characteristics.</p

Brown Fat Activity Differences between Athletes and Non-Athletes.

<p><b>(1A)</b> Maximum Intensity Projection of an 18F-FDG PET-CT scan performed in a non-athlete shows multiple and bilateral foci of increased glucose uptake along the laterocervical, supraclavicular, axillary regions, corresponding to metabolically active BAT in these regions. (<b>1B)</b> Maximum Intensity Projection of an 18F-FDG whole body PET-CT scan performed in an athlete. Physiological glucose uptake is seen in the brain, salivary glands and myocardium. No active BAT is seen in this patient.</p

Baseline and Brown Fat Characteristics Athletes and Non-athletes (NA).

<p>Baseline and Brown Fat Characteristics Athletes and Non-athletes (NA).</p

Brown Fat Volume Differences between Athletes and Non-Athletes.

<p>Brown fat volume trended lower in athletes (dark grey) compared to non-athletes (light grey).</p

Comparing Outcomes of Two Types of Bariatric Surgery in an Adolescent Obese Population: Roux-en-Y Gastric Bypass versus Sleeve Gastrectomy

Background: Obesity is prevalent among adolescents and is associated with serious health consequences. Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) are bariatric procedures that cause significant weight loss in adults and are increasingly being performed in adolescents with morbid obesity. Data comparing outcomes of RYGB versus SG in this age-group are scarce. This study aims to compare short-term (1-6 months) and longer-term (7-18 months) body mass index (BMI) and biochemical outcomes following RYGB and SG in adolescents/young adults.Methods: A retrospective study using data extracted from medical records of patients 16-21 years who underwent RYGB or SG between 2012-2014 at a tertiary care academic medical center. Results: Forty-six patients were included in this study: 24 underwent RYGB and 22 underwent SG. Groups did not differ for baseline age, sex, race or BMI. BMI reductions were significant at 1-6 months and 7-18 months within groups (p<0.0001), but did not differ by surgery type (p= 0.65 and 0.09, for 1-6 months and 7-18 months, respectively). Over 7-18 months, within-group improvement in low density lipoprotein (LDL) (-24±6 in RYGB, p=0.003, vs. -7±9mg/dL in SG, p=0.50) and non-high density lipoprotein (non-HDL) cholesterol (-23±8 in RYGB, p=0.02, vs. -12±7 in SG, p=0.18) appeared to be of greater magnitude following RYGB. However, differences between groups did not reach statistical significance. When divided by non-alcoholic steatohepatitis stages (NASH), patients with Stage II-III NASH had greater reductions in ALT levels vs. those with Stage 0-I NASH (-45±18 vs -9±3, p=0.01) after 7-18 months. RYGB and SG groups did not differ for the magnitude of post-surgical changes in liver enzymes. Conclusion: RYGB and SG did not differ for the magnitude of BMI reduction across groups, though changes trended higher following RYGB. Further prospective studies are needed to confirm these findings