Objectives-To examine the relations of race, sex, adiposity, adipokines and physical activity to telomere length in adolescents.Study design-Leukocyte telomere length (T/S ratio) was assessed cross-sectionally in 667 adolescents (aged 14-18 years, 48% blacks, 51% girls) using a quantitative PCR method. Generalized Estimating Equations analyses were performed.Results-Black adolescents had longer telomeres than white adolescents (age and sex adjusted T/S ratio ± SE: 1.32 ± 0.01 vs. 1.27 ± 0.01, p=0.014) and girls had longer telomeres than boys (age and race adjusted T/S ratio ± SE: 1.31 ± 0.01 vs. 1.27 ± 0.01, p=0.007). None of the adiposity or adipokine measures explained a significant proportion of the variance in telomere length. Vigorous physical activity was positively associated with telomere length (adjusted R 2 =0.019, p=0.009) and accounted for 1.9% of the total variance only in girls.Conclusion-This study, conducted in a biracial adolescent cohort, demonstrated that: (1) race and sex differences in telomere length have already emerged during adolescence; (2) adiposity and adipokines are not associated with telomere length at this age; and (3) the anti-aging effect of vigorous physical activity may begin in youth especially in girls. KeywordsTelomere length; race; sex; adiposity; adipokines; physical activity; adolescents © 2010 Mosby, Inc. All rights reserved. * Address for correspondence: Haidong Zhu MD PhD, Georgia Prevention Institute, Department of Pediatrics, Medical College of Georgia, Augusta, GA, USA, 1120 15 th Street, HS-1640, Augusta, GA 30912-3715, Phone: (706) 721 5470, hzhu@mail.mcg.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.The authors declare no conflicts of interest. In contrast to the considerable information available in adult literature, the knowledge about LTL in adolescent populations is limited. Therefore, the present study aimed to examine the relations of race, sex, adiposity, adipokines and physical activity to telomere length in a relatively large sample of healthy white and black adolescents. NIH Public Access MethodsHealthy adolescents aged 14-18 years including 348 whites and 319 blacks (324 boys) were previously recruited from local public high schools. Written informed consent was obtained from these 18 year olds. For 14-17 year olds, parental consent and subject assent were obtained. Race was determined by self-report of each subject, and by a parent if subject was under 18 years of age. The adolescents were apparently healthy, had no contraindications to any of the study procedures and were taking no medication t...

Though adolescents consume more fructose than any other age group, the relationship between fructose consumption and markers of cardiometabolic risk has not been established in this population. We determined associations of total fructose intake (free fructose plus one-half the intake of free sucrose) with cardiometabolic risk factors and type of adiposity in 559 adolescents aged 14-18 y. Fasting blood samples were measured for glucose, insulin, lipids, adiponectin, and C-reactive protein. Diet was assessed with 4-7 24-h recalls and physical activity (PA) was determined by accelerometry. Fat-free soft tissue (FFST) mass and fat mass were measured by DXA. The s.c. abdominal adipose tissue (SAAT) and visceral adipose tissue (VAT) were assessed using MRI. Multiple linear regression, adjusting for age, sex, race, Tanner stage, FFST mass, fat mass, PA, energy intake, fiber intake, and socioeconomic status, revealed that fructose intake was associated with VAT (β = 0.13; P = 0.03) but not SAAT (P = 0.15). Significant linear upward trends across tertiles of fructose intake were observed for systolic blood pressure, fasting glucose, HOMA-IR, and C-reactive protein after adjusting for the same covariates (all P-trend < 0.04). Conversely, significant linear downward trends across tertiles of fructose intake were observed for plasma HDL-cholesterol and adiponectin (both P-trend < 0.03). When SAAT was added as a covariate, these trends persisted (all P-trend < 0.05). However, when VAT was included as a covariate, it attenuated these trends (all P-trend > 0.05). In adolescents, higher fructose consumption is associated with multiple markers of cardiometabolic risk, but it appears that these relationships are mediated by visceral obesity.

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