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1.  Meal Skipping Linked to Increased Visceral Adipose Tissue and Triglycerides in Overweight Minority Youth 
Obesity (Silver Spring, Md.)  2013;22(5):E77-E84.
Objective
To investigate the impact of eating frequency on dietary intake, physical activity (PA), metabolic, and adiposity measures in minority youth.
Design and Methods
This analysis included 185 overweight (≥85th BMI percentile) Hispanic and African American youth (8–18 years) with the following cross-sectional measures: height, weight, BMI, dietary intake, body composition, metabolic parameters, PA, visceral adipose tissue (VAT), and subcutaneous adipose tissue. Each eating occasion (EO) was defined as ≥50 calories and ≥15 minutes from any previous EO. Participants were dichotomized based on EOs per 24-h into meal skippers <3 EO (MS; n=27) or normal/frequent eaters ≥3 EO (NFE; n=158). ANCOVAs were used to assess dietary intakes, metabolic outcomes, adiposity, and PA between eating frequency groups.
Results
MS compared to NFE consumed 24% fewer calories per 24-h (p≤0.01), 21% more calories per EO (p≤0.01), ate 40% less often (p≤0.01), had 18% higher triglycerides (p=0.03), and 26% more VAT (p=0.03), with no differences in PA.
Conclusions
Although meal skipping was associated with decreased energy intake, it was linked to increased calories per EO and higher triglycerides and VAT, which are strong indicators of deleterious metabolic profiles. These findings elucidate that meal skipping may be associated with increased VAT and related metabolic diseases in high-risk minority youth.
doi:10.1002/oby.20487
PMCID: PMC3759606  PMID: 23613461
Eating Behaviors; Life Styles; Minorities; Visceral Fat; Triglyceride
2.  Increasing Physical Activity Decreases Hepatic Fat and Metabolic Risk Factors 
This study assessed the changes in time spent in moderate to vigorous physical activity (MVPA) on fat depots, insulin action, and inflammation. Longitudinal data were generated from 66 Hispanic adolescents (15.6±1.1 yr; BMI percentile 97.1±3.0) who participated in a 16-wk nutrition or nutrition+exercise intervention. There were no effects of the intervention on PA, but there were inter-individual changes in PA. For purposes of this analysis, all intervention groups were combined to assess how changes in PA during 16 wk affected changes in adiposity, insulin action, and markers of inflammation. MVPA was assessed by 7-day accelerometry, total body fat via DXA, liver fat by MRI, and insulin, glucose and HOMA-IR via a fasting blood draw. A repeated measures ANCOVA was used to assess the effect of MVPA on fat depots, insulin action, and inflammatory markers. Sixty-two percent of participants increased MVPA (mean increase, 19.7±16.5 min/day) and 38% decreased MVPA (mean decrease, 10.7±10.1 min/day). Those who increased MVPA by as little as 20 min per day over 16 wk, compared to those who decreased MVPA, had significant reductions in liver fat (−13% vs. +3%; P=0.01), leptin levels (−18% vs. +4%; P=0.02), and fasting insulin (−23% vs. +5%; P=0.05). These findings indicate that a modest increase in MVPA can improve metabolic health in sedentary overweight Hispanic adolescents.
PMCID: PMC3695481  PMID: 23814456
Moderate-to-Vigorous Physical Activity; Obesity
3.  Effects of a randomized maintenance intervention on adiposity and metabolic risk factors in overweight minority adolescents 
Pediatric Obesity  2012;7(1):16-27.
Objective
To assess the effects of a maintenance program (monthly newsletters versus monthly group classes and telephone behavioral sessions) on obesity and metabolic disease risk at one year in overweight minority adolescents.
Methods
After a 4-month nutrition and strength training intervention, 53 overweight Latino and African American adolescents (15.4 ±1.1 yrs) were randomized into one of two maintenance groups for 8 months: monthly newsletters (n=23) or group classes (n=30; monthly classes + individualized behavioral telephone sessions). The following outcomes were measured at months 4 (immediately following the intense intervention) and month 12: height, weight, blood pressure, body composition via BodPod™, lipids and glucose/insulin indices via frequently sampled intravenous glucose tolerance test (FSIVGTT).
Results
There were no significant group by time interactions for any of the health outcomes. There were significant time effects in several outcomes for both groups from month 4 to 12: bench press and leg press decreased by 5% and 14% (p=0.004 & p=0.01), fasting insulin and acute insulin response decreased by 26% and 16% (p<0.001 & p=0.046); while HDL cholesterol and insulin sensitivity improved by 5% and 14% (p=0.042 and p=0.039).
Conclusions
Newsletters as opposed to group classes may suffice as follow-up maintenance programs to decrease type 2 diabetes and cardiovascular risk in overweight minority adolescents.
doi:10.1111/j.2047-6310.2011.00002.x
PMCID: PMC3313084  PMID: 22434736
Maintenance; Obesity Intervention; Type 2 Diabetes; Cardiovascular risk factors; Latino and African American adolescents
4.  Association of Breakfast Skipping With Visceral Fat and Insulin Indices in Overweight Latino Youth 
Obesity (Silver Spring, Md.)  2009;17(8):1528-1533.
Few studies have investigated the relationship between breakfast consumption and specific adiposity or insulin dynamics measures in children. The goal of this study is to determine whether breakfast consumption is associated with adiposity, specifically intra-abdominal adipose tissue (IAAT), and insulin dynamics in overweight Latino youth. Participants were a cross-sectional sample of 93 overweight (≥85th percentile BMI) Latino youth (10–17 years) with a positive family history of type 2 diabetes. Dietary intake was assessed by two 24-h recalls, IAAT, and subcutaneous abdominal adipose tissue (SAAT) by magnetic resonance imaging, body composition by dual-energy X-ray absorptiometry, and insulin dynamics by a frequently sampled intravenous glucose tolerance test and minimal modeling. Participants were divided into three breakfast consumption categories: those who reported not eating breakfast on either day (breakfast skippers; n = 20), those who reported eating breakfast on one of two days (occasional breakfast eaters; n = 39) and those who ate breakfast on both days (breakfast eaters; n = 34). Using analyses of covariance, breakfast omission was associated with increased IAAT (P = 0.003) independent of age, Tanner, sex, total body fat, total body lean tissue mass, and daily energy intake. There were no significant differences in any other adiposity measure or in insulin dynamics between breakfast categories. Eating breakfast is associated with lower visceral adiposity in overweight Latino youth. Interventions focused on increasing breakfast consumption are warranted.
doi:10.1038/oby.2009.127
PMCID: PMC2836758  PMID: 19424166
5.  Modifying Influence of Dietary Sugar in the Relationship Between Cortisol and Visceral Adipose Tissue in Minority Youth 
Obesity (Silver Spring, Md.)  2013;22(2):474-481.
Objective
Cortisol has been associated with preferential visceral adipose tissue (VAT) deposition; however findings in humans are mixed, which may be clarified when diet is considered.
Design and Methods
Participants included 165 African American and Latino, overweight adolescents (BMI% 97.2±3.2%, ages 13-18, 67% Latino, 66% female). Body composition was determined by DEXA, abdominal fat depots (VAT, subcutaneous (SAT)) by multiple-slice MRI, time-controlled serum sample to measure cortisol, and 2-day multi-pass 24-hour dietary recall. Linear regression analysis examined the cross-sectional relationship between cortisol, and the interaction of diet and cortisol on adiposity measures. Sex, race, age and total body fat were a priori covariates.
Results
There was a significant interaction between cortisol and sugar (total and added) in the prediction of VAT (pinteraction<=0.05). Amongst participants with high total or added-sugar intake, cortisol was significantly associated with VAT (β=0.031 p<0.001; β=0.026 p<0.001), with no relationship in low consumers of total or added-sugar.
Conclusion
Dietary sugar may play an important role in modifying the relationship between cortisol and VAT, such that cortisol is significantly associated with elevated VAT under conditions of high sugar intake.
doi:10.1002/oby.20594
PMCID: PMC3946447  PMID: 23929660
Adolescence; Cortisol; Omega-3 fatty acids; Sugar; visceral fat
6.  The impact of gestational diabetes mellitus on pubertal changes in adiposity and metabolic profiles in Latino offspring 
The Journal of pediatrics  2012;162(4):741-745.
Objective
To examine the impact of maternal gestational diabetes mellitus (GDM) status on longitudinal changes in adiposity and metabolic variables in overweight Latino offspring (from age 8– 20 years) across puberty.
Study design
This is a longitudinal cohort of 210 overweight Latino children who were measured annually for 3 ± 1 years for: Tanner stage via physical examination, adiposity via dual-energy X-ray absorptiometry and magnetic resonance imaging, lipids, glucose and insulin action via oral glucose tolerance test and frequently sampled intravenous glucose tolerance test. Linear mixed-effects modeling estimated the impact of maternal GDM status on baseline and changes in adiposity and metabolic variables across puberty.
Results
Twenty-two percent of offspring were from GDM pregnancies. At baseline, GDM offspring were heavier at birth, had more family history of type 2 diabetes, and were less likely to have been breastfeed (any duration). GDM offspring compared with non-GDM offspring had greater increases in total body fat (+6.5% vs +4.5%; p=0.03) and steeper declines in acute insulin response (−39% vs. −17%; p<0.001) and disposition index (−57% vs. −35%; p<0.001) across Tanner stages, independent of ethnicity, sex, breastfeeding status, family history of diabetes, and baseline and changes in body composition.
Conclusion
These findings confirm the elevated risk for excess adiposity and type 2 diabetes in GDM offspring, and further highlight the need for interventions targeting Latino GDM and their offspring.
doi:10.1016/j.jpeds.2012.10.001
PMCID: PMC3578029  PMID: 23149173
Longitudinal study; Hispanics; overweight and obesity; Gestional diabetes; type 2 diabetes risk; puberty
7.  Objective Habitual Physical Activity and Estradiol Levels in Obese Latina Adolescents 
Background
Lifetime physical activity (PA) is associated with decreased breast cancer (BC) risk; reports suggest that PA during adolescence contributes strongly to this relationship. PA lowers production of sex hormones, specifically estradiol, or decreases insulin resistance (IR), thereby lowering risk. Overweight Latina adolescents are insulin resistant and exhibit low levels of PA, potentially increasing their future BC risk.
Methods
37 obese Latina adolescents (15.7 ±1.1 yrs) provided measures of PA using accelerometry; plasma follicular phase estradiol, sex-hormone binding globulin, total and free testosterone, dehydroepiandrosterone-sulfate (DHEAS); IR using HOMA-IR; body composition via DEXA. Partial correlations and stepwise linear regressions assessed cross-sectional relationships between sex hormones, IR and PA. Body composition, and age were included a priori as covariates.
Results
Estradiol was negatively associated with accelerometer counts per minute (CPM) (r= −0.4; p=0.02), percent time spent in moderate PA (%MPA) (r= −0.5; p=0.006), and percent time in moderate or vigorous PA (%MVPA) (r= −0.5; p=0.007). DHEAS was positively associated with CPM (r=0.4, p=0.009), %MPA (r=0.3, p=0.04), and %MVPA (r=0.3, p=0.04). Other sex hormones and IR were not associated with PA measures.
Conclusion
This study is the first to show that higher habitual PA was inversely associated with estradiol in obese adolescents.
PMCID: PMC3779056  PMID: 23038707
Accelerometer; insulin resistance; sex hormones; breast cancer
8.  Subclinical atherosclerosis in Latino youth: Progression of carotid intima media thickness (CIMT) and its relationship to cardiometabolic risk factors 
The Journal of pediatrics  2011;158(6):935-940.
Objective
To assess carotid artery intima media thickness (CIMT) change over two years in overweight Latino adolescents and examine its relationship to cardiometabolic risk.
Study design
72 healthy overweight male and female Latino adolescents (mean age: 14.5±1.7 yrs; mean BMI: 31.5±6.9 kg/m2) were evaluated at baseline and 2 years later for: CIMT by high resolution B-mode ultrasound, the metabolic syndrome and its features, body composition by DEXA and MRI, and glucose/insulin measures by fasting blood, and oral and intravenous glucose tolerance tests.
Results
Baseline CIMT did not differ from 2-year follow-up; however 38 participants increased CIMT (0.017±0.003mm; +2.8%) and 34 decreased (-0.019±0.002mm; −3.1%). ANCOVA analyses showed that participants with CIMT progression had higher baseline LDL-cholesterol and total cholesterol (91.3±3.4 and 150.3±3.9mg/dL) compared with those with CIMT regression (78.1±3.6 and 135.6±4.2mg/dL, p<0.05), independent of sex, baseline CIMT, age, and height. In multivariate regression, LDL-cholesterol was the sole predictor of CIMT progression, but the effect was small (odds of CIMT progression increased by 3% for each 1 mg/dL higher baseline LDL-cholesterol [95% CI: 1.004-1.006, p=0.03].
Conclusions
These results indicate a high variability in the magnitude of CIMT change in growing overweight Latino youth and support the use of LDL-cholesterol to assess sub-clinical atherosclerosis risk in this population.
doi:10.1016/j.jpeds.2010.12.008
PMCID: PMC3767153  PMID: 21238987
Obesity; Cardiovascular disease risk; Ultrasound imaging
9.  Persistence of the metabolic syndrome over 3 annual visits in overweight Latino children: Association with progressive risk for type 2 diabetes 
The Journal of pediatrics  2009;155(4):535-541.
Objective
To examine whether persistent Metabolic syndrome (MetS) was associated with risk for type 2 diabetes in overweight Latino children.
Study design
73 participants (age 11.0±1.7 years) from a longitudinal study were classified as: NEVER (negative for MetS at all 3 visits); INTERMITTENT (positive for MetS at 1 or 2 visits); or PERSISTENT (positive for MetS at all 3 visits). Measures included DEXA, MRI, 2-h oral glucose tolerance test, and frequently sampled intravenous glucose tolerance test.
Results
The PERSISTENT group had a faster rate of fat mass gain than the NEVER group (20% vs. 15% gain of baseline value, p<0.05 for time*group interaction (time= visit)). Independent of body composition, the PERSISTENT group increased by 70% in insulin incremental area under the curve, and the other groups decreased (p<0.05 for time*group interaction). Despite no time*group interactions for insulin sensitivity, acute insulin response, or disposition index, the PERSISTENT maintained 43% lower insulin sensitivity (p<0.01) and by visit 2 had a 25% lower disposition index (p<0.05) compared with the NEVER group.
Conclusion
Participants with persistent MetS had accelerated fat gain, increasing insulin response to oral glucose, and lower insulin sensitivity and beta cell function, indicators of progressively greater risk for type 2 diabetes.
doi:10.1016/j.jpeds.2009.04.008
PMCID: PMC3709847  PMID: 19555970
longitudinal; beta cell function; insulin sensitivity; insulin resistance; insulin IAUC
10.  Sociocultural and Socioeconomic Influences on Type 2 Diabetes Risk in Overweight/Obese African-American and Latino-American Children and Adolescents 
Journal of Obesity  2013;2013:512914.
Purpose. It is unclear whether sociocultural and socioeconomic factors are directly linked to type 2 diabetes risk in overweight/obese ethnic minority children and adolescents. This study examines the relationships between sociocultural orientation, household social position, and type 2 diabetes risk in overweight/obese African-American (n = 43) and Latino-American (n = 113) children and adolescents. Methods. Sociocultural orientation was assessed using the Acculturation, Habits, and Interests Multicultural Scale for Adolescents (AHIMSA) questionnaire. Household social position was calculated using the Hollingshead Two-Factor Index of Social Position. Insulin sensitivity (SI), acute insulin response (AIRG) and disposition index (DI) were derived from a frequently sampled intravenous glucose tolerance test (FSIGT). The relationships between AHIMSA subscales (i.e., integration, assimilation, separation, and marginalization), household social position and FSIGT parameters were assessed using multiple linear regression. Results. For African-Americans, integration (integrating their family's culture with those of mainstream white-American culture) was positively associated with AIRG (β = 0.27 ± 0.09, r = 0.48, P < 0.01) and DI (β = 0.28 ± 0.09, r = 0.55, P < 0.01). For Latino-Americans, household social position was inversely associated with AIRG (β = −0.010 ± 0.004, r = −0.19, P = 0.02) and DI (β = −20.44 ± 7.50, r = −0.27, P < 0.01). Conclusions. Sociocultural orientation and household social position play distinct and opposing roles in shaping type 2 diabetes risk in African-American and Latino-American children and adolescents.
doi:10.1155/2013/512914
PMCID: PMC3666294  PMID: 23762538
11.  Randomized Controlled Trial to Improve Adiposity, Inflammation, and Insulin Resistance in Obese African-American and Latino Youth 
Obesity (Silver Spring, Md.)  2011;20(4):811-818.
The purpose of this study was to examine ethnic differences in the metabolic responses to a 16-week intervention designed to improve insulin sensitivity (SI), adiposity, and inflammation in obese African-American and Latino adolescents. A total of 100 participants (African Americans: n = 48, Latino: n = 52; age: 15.4 ± 1.1 years, BMI percentile: 97.3 ± 3.3) were randomly assigned to interventions: control (C; n = 30), nutrition (N; n = 39, 1×/week focused on decreasing sugar and increasing fiber intake), or nutrition + strength training (N+ST; n = 31, 2×/week). The following were measured at pre- and postintervention: strength, dietary intake, body composition (dual-energy X-ray absorptiometry/magnetic resonance imaging) and glucose/insulin indexes (oral glucose tolerance test (OGTT)/intravenous glucose tolerance test (IVGTT)) and inflammatory markers. Overall, N compared to C and N+ST reported significant improvements in SI (+16.5% vs. −32.3% vs. −6.9% respectively, P < 0.01) and disposition index (DI: +15.5% vs. −14.2% vs. −13.7% respectively, P < 0.01). N+ST compared to C and N reported significant reductions in hepatic fat fraction (HFF: −27.3% vs. −4.3% vs. 0% respectively, P < 0.01). Compared to N, N+ST reported reductions in plasminogen activator inhibitor-1 (PAI-1) (−38.3% vs. +1.0%, P < 0.01) and resistin (−18.7% vs. +11.3%, P = 0.02). There were no intervention effects for all other measures of adiposity or inflammation. Significant intervention by ethnicity interactions were found for African Americans in the N group who reported increases in total fat mass, 2-h glucose and glucose incremental areas under the curve (IAUC) compared to Latinos (P’s < 0.05). These interventions yielded differential effects with N reporting favorable improvements in SI and DI and N+ST reporting marked reductions in HFF and inflammation. Both ethnic groups had significant improvements in metabolic health; however some improvements were not seen in African Americans.
doi:10.1038/oby.2010.343
PMCID: PMC3106142  PMID: 21293446
12.  Fasting Indicators of Insulin Sensitivity: Effects of Ethnicity and Pubertal Status 
Diabetes Care  2011;34(4):994-999.
OBJECTIVE
To examine the relationship of fasting indicators of insulin sensitivity with a more invasive measure of insulin sensitivity (frequently sampled intravenous glucose tolerance test [FSIVGTT]) and the effect of Tanner stage and ethnicity on that relationship.
RESEARCH DESIGN AND METHODS
Data were analyzed from 149 overweight girls (97 Hispanic and 52 African American) who were either in the early stages of maturation defined by Tanner stages 1 or 2 (52 Hispanic and 18 African American) or in the later stages of maturation defined by Tanner stages 4 and 5 (45 Hispanic and 34 African American). Fasting indicators of insulin sensitivity (IS) included fasting insulin and glucose and the homeostasis model assessment of insulin resistance (HOMA-IR). IS was derived from an FSIVGTT with minimal modeling.
RESULTS
In Tanner stages 1 and 2, all fasting indicators were significantly associated with IS: (fasting insulin: r = −0.67, P < 0.01; HOMA: r = −0.66, P < 0.01) with no significant influence of ethnicity on these relationships. In Tanner stages 4 and 5, however, all fasting indicators were associated with IS in African American girls (fasting insulin: r = −0.55, P < 0.01; HOMA: r = −0.47, P < 0.01), but none of the indicators were significantly associated with IS in Hispanic girls.
CONCLUSIONS
Fasting indicators were reflective of IS for girls in Tanner stages 1 and 2, regardless of ethnicity and may provide a clinical measure of future risk for type 2 diabetes. In the latter stages of maturation, however, more invasive measures are warranted to adequately determine IS in clinical practice.
doi:10.2337/dc10-1593
PMCID: PMC3064063  PMID: 21357795
13.  Ethnic Differences in Pancreatic Fat Accumulation and Its Relationship With Other Fat Depots and Inflammatory Markers 
Diabetes Care  2011;34(2):485-490.
OBJECTIVE
Visceral adipose tissue (VAT) and hepatic fat are associated with insulin resistance and vary by sex and ethnicity. Recently, pancreatic fat fraction (PFF) has also been linked with increasing obesity. Our aim was to assess ethnic and sex differences in PFF and its relationship to other fat depots, circulating free fatty acids (FFA), insulin secretion and sensitivity, and inflammation in obese adolescents and young adults.
RESEARCH DESIGN AND METHODS
We examined 138 (40 males, 98 females) obese Hispanics and African Americans (13–25 years). Subcutaneous adipose tissue and VAT volumes, hepatic fat fraction (HFF), and PFF were determined by magnetic resonance imaging. Insulin sensitivity and β-cell function were assessed during an intravenous glucose tolerance test.
RESULTS
Hispanics had higher PFF than African Americans (7.3 ± 3.8 vs. 6.2 ± 2.6%, P = 0.03); this ethnic difference was higher in young adults compared with children and adolescents (ethnicity × age: P = 0.01). Males had higher PFF than females (P < 0.0001). PFF was positively correlated with VAT (r = 0.45, P < 0.0001), HFF (r = 0.29, P < 0.0001), and FFA (r = 0.32, P = 0.001). PFF positively correlated with inflammatory markers but lost significance when adjusted for VAT. In multiple stepwise regression analysis, VAT and FFA were the best predictors of PFF (adjusted R2 = 0.40). There were no significant correlations between PFF and markers of insulin sensitivity or β-cell function.
CONCLUSIONS
PFF is higher in Hispanics than African Americans, and this difference increases with age. In young obese individuals, PFF is related to VAT, HFF, and circulating FFA, thus possibly contributing to their increased risk for type 2 diabetes and related metabolic disorders.
doi:10.2337/dc10-0760
PMCID: PMC3024373  PMID: 21270204
14.  Effects of PNPLA3 on Liver Fat and Metabolic Profile in Hispanic Children and Adolescents 
Diabetes  2010;59(12):3127-3130.
OBJECTIVE
A genome-wide study of adults identified a variant of PNPLA3 (rs738409) associated with ∼twofold higher liver fat. The purpose of this study was to examine the influence of PNPLA3 genotype on liver fat and other related metabolic outcomes in obese Hispanic children and adolescents.
RESEARCH DESIGN AND METHODS
Three hundred and twenty-seven Hispanics aged 8–18 years were genotyped for rs738409. One hundred and eighty-eight subjects had measures of visceral (VAT) and subcutaneous (SAT) adipose tissue volume and hepatic (HFF) and pancreatic (PFF) fat fraction by magnetic resonance imaging. One hundred and thirty-nine subjects did not have HFF measures but had extensive measures of insulin sensitivity and fasting lipids.
RESULTS
Liver fat in GG subjects was 1.7 and 2.4 times higher than GC and CC (11.1 ± 0.8% in GG vs. 6.6 ± 0.7% in GC and 4.7 ± 0.9% in CC; P < 0.0001), and this effect was observed even in the youngest children (8–10 years of age). The variant was not associated with VAT, SAT, PFF, or insulin sensitivity or other glucose/insulin indexes. However, Hispanic children carrying the GG genotype had significantly lower HDL cholesterol (40.9 ± 10.9 in CC vs. 37.0 ± 8.3 in CG vs. 35.7 ± 7.4 in GG; P = 0.03) and a tendency toward lower free fatty acid levels (P = 0.06).
CONCLUSIONS
These results provide new evidence that the effect of the PNPLA3 variant is apparent in Hispanic children and adolescents, is unique to fat deposition in liver as compared with other ectopic depots examined, and is associated with lower HDL cholesterol.
doi:10.2337/db10-0554
PMCID: PMC2992774  PMID: 20852027
15.  Increased physical activity and reduced adiposity in overweight Hispanic adolescents 
Purpose
Objectives of this study were to examine 1) whether changes in total PA (counts/minute, cpm) and time spent in moderate to vigorous PA (MVPA) are associated with changes in adiposity and 2) whether energy intake influences the relationship between changes in PA and changes in adiposity in overweight Hispanic adolescents.
Methods
Analysis included 38 overweight (BMI ≥ 85th %ile) Hispanic adolescents with complete pre- and post-test data on relevant variables after participating in a 16-week intervention. The intervention treatment did not influence physical activity, so the sample was combined and randomization group was adjusted for in the analysis. Body composition by DEXA, 7-day physical activity by accelerometry, and dietary intake by 3-day diet records were assessed pre- and post-intervention.
Results
Within individuals, the mean increase of PA (n=19) and mean decrease of PA (n=19) was approximately 105 cpm. A 100 cpm increase in total PA was associated with a decrease of 1.3 kg fat mass and 0.8% body fat after adjusting for pre-test adiposity, PA, age, sex, and treatment (p < 0.05). Controlling for energy intake modestly strengthened the relationships between total PA and fat mass and percent body fat. Changes in MVPA were not related to changes in adiposity after controlling for total PA (p>0.05).
Conclusion
Increasing total PA by 28% (100 cpm) was associated with a decrease of 1.4 kg of fat mass and 1% body fat over 16 weeks in overweight Hispanic adolescents independent of intervention group assignment. Increases in total physical activity, as compared to MVPA, may be sufficient to improve body composition in overweight Hispanic adolescents.
doi:10.1249/MSS.0b013e3181b9c45b
PMCID: PMC3163456  PMID: 19952807
Obesity; children; Hispanic; accelerometer; youth; DEXA
16.  Dietary Intake and the Metabolic Syndrome in Overweight Latino Children 
Little is known about the relationship between diet and metabolic health in Latino children, a population at increased risk for diabetes. The present study evaluates diet composition and the metabolic syndrome in a cross-sectional sample of 109 overweight Latino children aged 10 to 17 years with a family history of type 2 diabetes. Dietary intake was assessed by two 24-hour recalls. Associations between nutrients and features of the metabolic syndrome were examined using multiple linear regression and analysis of covariance. Log cholesterol intake was positively associated with log systolic blood pressure (β=0.034, P=0.017) and log soluble dietary fiber intake was inversely associated with log waist circumference (β=−0.069, P=0.036). Log soluble fiber intake was significantly higher in participants with 0 features compared to those with 3+ features of the metabolic syndrome (P=0.046), which translates to 5.2 g vs 4.1 g soluble fiber daily. No other significant associations were found between dietary variables and either the individual features of the metabolic syndrome or the clustering of metabolic syndrome components. Increases in soluble fiber through the daily consumption of fruits, vegetables, and beans may improve metabolic health in Latino children.
doi:10.1016/j.jada.2008.05.006
PMCID: PMC2882193  PMID: 18656576
17.  A high sugar, low fiber meal leads to higher leptin and physical activity levels in overweight Latina females as opposed to a low sugar, high fiber meal 
Acute effects of high sugar, low fiber meals (HS) versus low sugar, high fiber meals (LS) on hormones and behavior were studied in 10 overweight Latina females, age 11-12, using a crossover design. In this exploratory pilot study, articipants arrived fasted at an observation laboratory on two occasions, and randomly received either a HS meal or a LS meal at each visit. Glucose, insulin, and leptin were assayed from serum drawn at 0, 15, 30, 60, 90 and 120 minutes. Ad-libitum snacks were provided at 120 minutes. Physical activity was measured using an observational system that provides data on time spent lying down, sitting, standing, walking, and in vigorous activity. Data was collected between March, 2005 and July, 2006. In the HS condition, glucose and leptin levels decreased more slowly, glucose levels were higher at 60 minutes (111.2 mg/dl vs 95.4 mg/dl, P = .03), leptin levels were higher at 90 minutes (49.3 vs 46.7 ng/ml, P = .017) than in the LS condition. Meals did not effect insulin or ad-libitum dietary intake. Sitting, standing, lying down and vigorous activity differed by condition, but not walking. Participants were significantly more active in the first 30-60 post-HS minutes, but after 60 minutes there was a trend for activity to be lower after the HS meal vs. the LS meal. High sugar meals sustain glucose and leptin levels longer, which may play an important role in modulating levels of physical activity in this group at high risk of obesity-related disease.
doi:10.1016/j.jada.2009.03.013
PMCID: PMC2768570  PMID: 19465188
18.  A brief dietary screener: Appropriate for overweight Latino adolescents? 
To assess whether a brief dietary screener designed to assess fast food and beverage consumption in a primarily Caucasian, adolescent population, is also valid and reliable in an overweight, adolescent, Latina population. This screener was developed by University of Minnesota to assess beverage consumption (9 items) and fast food consumption (13 items) in normal weight, primarily Caucasian, adolescents (ages 11–18). Thirty-five at risk for overweight (BMI ≥85th percentile), adolescent (ages 14–17), Latina females were recruited from East Los Angeles and completed the screener twice, approximately seven to 14 days apart, during the fall of 2007. Dietary intake was also assessed by three-day diet records. Spearman correlation and simple Kappas were employed for test-retest assessment and comparisons between the screener and the records. Test-retest assessment yielded a mean Spearman or Kappa statistic of 0.49 with 17 of the 21 responses being significant (P<0.05). Validity was much lower and yielded a Kappa statistic of only 0.08 and no responses were significant. Although this screener appeared to be a valid and reliable measure to assess beverage and fast food consumption in a primarily Caucasian, adolescent population, it does not appear to be appropriate for an overweight Latina female adolescent population.
doi:10.1016/j.jada.2008.12.025
PMCID: PMC2684875  PMID: 19328270
Validation and Reliability; Brief Dietary Screener; Overweight Latino Adolescents
19.  Reduction in Added Sugar Intake and Improvement in Insulin Secretion in Overweight Latina Adolescents 
Background
To date, no study has assessed the effects of modifying carbohydrate intake (specifically decreasing added sugar and increasing fiber) on insulin secretion, nor has any study used an overweight Latino adolescent population. The objective of this study was to examine whether changes in dietary intake, specifically reductions in added sugar and/or increases in fiber, following a 12-week, modified carbohydrate dietary intervention, were associated with changes in insulin secretion and other metabolic risk factors for type 2 diabetes.
Methods
Participants were 16 overweight (≥85th percentile BMI) Latina adolescent females (12–17 years) who completed a 12-week modified carbohydrate intervention. Dietary intake was assessed by 3-day diet records, body composition by dual-energy X-ray absorptiometry, and insulin dynamics by an extended 3-hour oral glucose tolerance test (OGTT) at baseline and post-intervention.
Results
There was a trend for unadjusted change in reported added sugar intake (% of kcals) to be associated with change in insulin secretion, i.e. IAUC (r = 0.47; p = 0.075), and this relationship became significant after controlling for age, baseline insulin secretion, added sugar and adiposity, and change in adiposity (r = 0.85; p < 0.05). No other changes in dietary variables were related to changes in insulin secretion or other metabolic risk factors for type 2 diabetes.
Conclusions
Participants with greater reductions in added sugar intake showed significantly greater improvements in insulin secretion following a modified carbohydrate nutrition intervention. These findings suggest that interventions focused on decreasing added sugar intake have the potential to reduce type 2 diabetes risk in overweight youth.
doi:10.1089/met.2006.0038
PMCID: PMC2847394  PMID: 18370826
20.  Randomized Control Trial to Improve Adiposity and Insulin Resistance in Overweight Latino Adolescents 
Obesity (Silver Spring, Md.)  2009;17(8):1542-1548.
Few randomized trials attempt to improve insulin sensitivity and associated metabolic risks in overweight Latino youth. The purpose of this study is to examine the effects of a modified carbohydrate nutrition program combined with strength training on insulin sensitivity, adiposity, and other type 2 diabetes risk factors in overweight Latino adolescents. In a 16-week randomized trial, 54 overweight Latino adolescents (15.5 ± 1.0 years) were randomly assigned to: (i) Control (C; n = 16), (ii) Nutrition (N; n = 21), or (iii) Nutrition + Strength training (N+ST; n = 17). The N group received modified carbohydrate nutrition classes (once per week), while the N+ST received the same nutrition classes plus strength training (twice per week). The following were measured at pre- and postintervention: strength by 1-repetition maximum, dietary intake by 3-day records, body composition by dual-energy X-ray absorptiometry, glucose/insulin indices by oral glucose tolerance test (OGTT) and intravenous glucose tolerance test with minimal modeling. Across intervention group effects were tested using analysis of covariance with post hoc pairwise comparisons. A significant overall intervention effect was found for improvement in bench press (P < 0.001) and reductions in energy (P = 0.05), carbohydrate (P = 0.04) and fat intake (P = 0.03). There were no significant intervention effects on insulin sensitivity, body composition, or most glucose/insulin indices with the exception of glucose incremental area under the curve (IAUC) (P = 0.05), which decreased in the N and N+ST group by 18 and 6.3% compared to a 32% increase in the C group. In conclusion, this intense, culturally tailored intervention resulted in no significant intervention effects on measured risk factors with the exception of a beneficial effect on glycemic response to oral glucose.
doi:10.1038/oby.2009.19
PMCID: PMC2846423  PMID: 19247280
21.  Aerobic and Strength Training Reduces Adiposity in Overweight Latina Adolescents 
Purpose
To date, no study has examined the synergistic effects of a nutrition and combination of aerobic and strength training (CAST) on both adiposity and metabolic parameters in overweight Latina adolescent females. The goal was to assess if a 16-wk nutrition plus CAST pilot study had stronger effects on reducing adiposity and on improving glucose/insulin indices compared with control (C), nutrition only (N), and a nutrition plus strength training (N + ST) groups.
Methods
In a 16-wk randomized trial, 41 overweight Latina girls (15.2 ± 1.1 yr) were randomly assigned to C (n = 7), N (n = 10), N + ST (n = 9), or N + CAST (n = 15). All intervention groups received modified carbohydrate nutrition classes (once a week), whereas the N + ST also received strength training (twice a week) and the N + CAST received a combination of strength and aerobic training (twice a week). The following were measured before and after intervention: strength by one repetition maximum, physical activity by the 7-d accelerometry and the 3-d physical activity recall, dietary intake by 3-d records, body composition by dual-energy x-ray absorptiometry (DEXA), glucose/insulin indices by oral glucose tolerance test, and intravenous glucose tolerance test with minimal modeling. Across intervention group, effects were tested using ANCOVA with post hoc pairwise comparisons.
Results
There were significant overall intervention effects for all adiposity measures (weight, body mass index [BMI], BMI z-scores, and DEXA total body fat), with a decrease of 3% in the N + CAST group compared with a 3% increase in the N + ST group (P ≤ 0.05). There was also an intervention effect for fasting glucose with the N group increasing by 3% and the N + CAST group decreasing by 4% (P ≤ 0.05).
Conclusion
The CAST was more effective than nutrition alone or nutrition plus strength training for reducing multiple adiposity outcomes and fasting glucose in overweight Latina girls. However, further research investigating and identifying intervention approaches that improve both adiposity and insulin indices, particularly in high-risk populations, are warranted.
doi:10.1249/MSS.0b013e31819b6aea
PMCID: PMC2836768  PMID: 19516150
EXERCISE; NUTRITION; INTERVENTION; OVERWEIGHT; TEENAGERS
22.  Cardiorespiratory fitness predicts changes in adiposity in overweight Hispanic boys 
Obesity (Silver Spring, Md.)  2008;16(5):1072-1077.
We have previously shown that cardiorespiratory fitness predicts increasing fat mass during growth in white and African-American youth, but limited data are available examining this issue in Hispanic youth. Study participants were 160 (53% boys) overweight (BMI ≥ 85th percentile for age and gender) Hispanic children (mean ± SD age at baseline =11.2 ± 1.7 yrs). Cardiorespiratory fitness, or VO2max, was measured via a maximal effort treadmill test at baseline. Body composition by dual-energy x-ray absorptiometry and Tanner stage by clinical exam were measured at baseline and annually thereafter for up to four years. Linear mixed models were used to examine the gender specific relationship between VO2max and increases in adiposity (change in fat mass independent of change in lean tissue mass) over four years. The analysis was adjusted for changes in Tanner stage, age, and lean tissue mass. In boys, higher VO2max at baseline was inversely associated with the rate of increase in adiposity (β= -0.001, p=0.03); this effect translates to a 15% higher VO2max at baseline resulting in a 1.38kg lower fat mass gain over four years. However, VO2max was not significantly associated with changes in fat mass in girls (β=0.0002, p=0.31). In overweight Hispanic boys, greater cardiorespiratory fitness at baseline was protective against increasing adiposity. In girls however, initial cardiorespiratory fitness was not significantly associated with longitudinal changes in adiposity. These results suggest that fitness may be an important determinant of changes in adiposity in overweight Hispanic boys but not in girls.
doi:10.1038/oby.2008.16
PMCID: PMC2780237  PMID: 18309303
Children; Youth; Longitudinal; Gender
23.  The relation of sugar intake to β cell function in overweight Latino children123 
Background
Few studies have investigated the association between sugar intake and insulin dynamics in children, and none have examined this association in overweight Latino youth.
Objective
We aimed to examine the relation between dietary components, especially sugar intake, and insulin dynamics in overweight Latino youth.
Design
We examined 63 overweight Latino children aged 9–13 y. Dietary intake was determined by 3-d records, and body composition was measured with dual-energy X-ray absorptiometry. Insulin sensitivity (SI), acute insulin response (AIR), and disposition index (an index of β cell function) were measured by using a frequently sampled intravenous-glucose-tolerance test and minimal modeling. Hierarchical regression analysis ascertained the potential independent relation between insulin dynamics and dietary components.
Results
The relation between macronutrient intake and any variable related to insulin dynamics was not significant. However, higher total sugar intake, although not related to SI, was significantly associated with lower AIR (β = −0.296, P = 0.045) and lower β cell function (β = −0.421, P = 0.043), independent of the covariates age, sex, body composition, Tanner stage, and energy intake. Sugar-sweetened beverage intakes trended toward inverse association with lower AIR (β = −0.219, P = 0.072) and β cell function (β = −0.298, P = 0.077).
Conclusions
In overweight Latino children, higher intakes of sugar and sugar-sweetened beverages were associated with lower AIR and disposition index, which suggested that these children already have early signs of poor β cell function. These results emphasize the need for early nutritional interventions to reduce daily sugar intake in overweight Latino children and potentially reduce their risk for type 2 diabetes.
PMCID: PMC2538439  PMID: 16280431
Latino adolescents; overweight; obesity; sugar; sugary beverages; β cells; disposition index; type 2 diabetes
24.  Interventions for improving metabolic risk in overweight Latino youth 
This review highlights various components of interventions that reduced obesity and type 2 diabetes risk factors among overweight Latino youth. A total of 114 overweight Latino adolescents completed one of four randomized controlled trials: 1) strength training (ST; boys only); 2) modified carbohydrate nutrition program (N); 3) combination of N+ST; or 4) N + Combination of Aerobic and ST (N+CAST; girls only). Measures included: strength by 1-repetition max, dietary intake by 3-d records, body composition by DEXA/MRI, glucose/insulin indices by oral and IV glucose tolerance tests. ST improved insulin sensitivity by 45% in Latino boys, and N, N+ST, and N+CAST improved glucose control in Latino boys and girls. The CAST approach reduced all adiposity measures by ∼3% in Latina girls. Participants who decreased added sugar, increased dietary fiber, and had increased parental attendance, regardless of intervention group, improved insulin action and reduced visceral adipose tissue. In conclusion, ST, CAST, and a modified carbohydrate nutrition program with separate parental classes were all successful components of the interventions that decreased obesity and related metabolic diseases.
doi:10.3109/17477161003770123
PMCID: PMC3752963  PMID: 20387989
Latino adolescents; randomized controlled trials; insulin sensitivity and secretion; diet and exercise interventions; adiposity

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