Publications (50) View all
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Article: The influence of ethnicity and gender on the association between measured obesity and cardiorespiratory fitness with self-rated overweight, physical activity and health.
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ABSTRACT: Background:Little is known about how ethnicity may influence how self-rated physical activity (PA) and obesity relates to measured obesity, cardiorespiratory fitness and self-rated health.Aims:To examine the influence of ethnicity on the association between: (1) self-rated and measured obesity; (2) self-reported PA and cardiorespiratory fitness; and (3) obesity and PA with self-rated health.Methods:Data from NHANES 1999-2004 (2,981 adults) was used.Results:Compared to white and overweight black men, Hispanic men were less likely to consider themselves overweight (OR = 0.36-0.56). Compared to white men, black active men were more likely to report being more active than their peers (OR = 1.44) but were less likely to be fit (OR = 0.74). Black active women and non-white overweight women were less likely to self-rate as having very good or excellent health as compared to white women with similar self-reported and measured health factors.Conclusions:Ethnicity and gender influence how self-rated and measured health factors interrelate.Perspectives in Public Health 03/2013; · 1.09 Impact Factor -
Article: Relationship Between Obesity and Obesity-Related Morbidities Weakens With Aging.
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ABSTRACT: BACKGROUND: A weak relationship exists between obesity and mortality risk in older populations, however, the influence of age on the relationship between obesity and morbidity is unclear. The objective of this study was to determine the influence of age on the relationship between obesity and cardiovascular disease, type 2 diabetes, dyslipidemia, and hypertension. METHODS: Data from the Third National Health and Nutrition Examination Survey (1988-1994) were used. Individuals were classified into specific age (young: 18-40; middle: 40-65; old: 65-75; and very old: ≥75 years) and body mass index (BMI; 18.5-24.9, >25-29.9, ≥ 30kg/m(2)) categories. Cardiovascular disease, type 2 diabetes, dyslipidemia, and hypertension were categorized using measured metabolic risk factors, physician diagnosis, or medication use. RESULTS: Age modified the relationship between BMI and cardiovascular disease (Age × BMI interaction, p = .049), dyslipidemia (Age × BMI interaction, p = .035 for men, p < .001 for women), and hypertension (Age × BMI interaction, p = .023) in women but not in men (p = .167). However, age did not modify the relationship between BMI and type 2 diabetes (Age × BMI interaction, p = .177). BMI was strongly associated with increased relative risk of cardiovascular disease, dyslipidemia, type 2 diabetes, and hypertension in the young and middle aged, however, the association between BMI and these metabolic conditions were much more attenuated with increasing age. CONCLUSION: A stronger association between obesity and prevalent metabolic conditions exists in young and middle-aged populations than in old and very old populations. Longitudinal studies are needed to verify these findings and to confirm the benefits of weight loss on health across the life span.The Journals of Gerontology Series A Biological Sciences and Medical Sciences 03/2013; · 4.60 Impact Factor -
Article: Changes in fat and skeletal muscle with exercise training in obese adolescents: comparison of whole-body MRI and dual energy X-ray absorptiometry.
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ABSTRACT: OBJECTIVE: We examined skeletal muscle (SM) and fat distribution using whole-body MRI in response to aerobic (AE) versus resistance exercise (RE) training in obese adolescents and whether DXA provides similar estimates of fat and SM change as MRI. DESIGN AND METHODS: Thirty-nine obese boys (12-18 yr) were randomly assigned to one of three 3-month interventions: AE (n=14), RE (n=14) or a control (n=11). RESULTS: At baseline, MRI-measured total fat was significantly greater than DXA-measured total fat [Δ=3.1 kg (95% CI: -0.4 to 7.4 kg, P<0.05)], wherein underestimation by DXA was greatest in those with the highest total fat. Overall, the changes in total fat were not significantly different between MRI and DXA [Δ= -0.4 kg (95% CI: -3.5 to 2.6 kg, P>0.05)], but DXA tended to overestimate MRI fat losses in those with larger fat losses. MRI-measured SM and DXA-measured LBM (lean body mass) were significantly correlated, but as expected the absolute values were different at baseline [Δ= -28.4 kg (95% CI: -35.4 to -21.3 kg, P<0.05)]. Further, DXA overestimated MRI gains in SM in those with larger SM gains. CONCLUSIONS: Although DXA and MRI-measured total and regional measures tended to be correlated at baseline and changes with exercise, there were substantial differences in the absolute values derived using DXA versus MRI. Further, there were systemic biases in the estimation between the methods wherein DXA tended to overestimate fat losses and SM gains compared to MRI. Thus, the changes in body composition observed are influenced by the method employed.Obesity 03/2013; · 4.28 Impact Factor -
Article: Effects of an overnight intravenous lipid infusion on intramyocellular lipid content and insulin sensitivity in African-American versus Caucasian adolescents.
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ABSTRACT: OBJECTIVE: To explain the predisposition for insulin resistance among African American (AA) adolescents, this study aimed to: 1) examine changes in intramyocellular lipid content (IMCL), and insulin sensitivity with intralipid (IL) infusion; and 2) determine whether the increase in IMCL is comparable between AA and Caucasian adolescents. MATERIALS AND METHODS: Thirteen AA and 15 Caucasian normal-weight adolescents (BMI <85th) underwent a 3-h hyperinsulinemic-euglycemic clamp, on two occasions in random order, after an overnight 12-h infusion of: 1) 20% IL and 2) normal saline (NS). IMCL was quantified by (1)H magnetic resonance spectroscopy in tibialis anterior muscle before and after IL infusion. RESULTS: During IL infusion, plasma TG, glycerol, FFA and fat oxidation increased significantly, with no race differences. Hepatic insulin sensitivity decreased with IL infusion with no difference between the groups. IL infusion was associated with a significant increase in IMCL, which was comparable between AA (Δ 105%; NS: 1.9±0.8 vs. IL: 3.9±1.6 mmol/kg wet weight) and Caucasian (Δ 86%; NS: 2.8±2.1 vs. IL: 5.2±2.4 mmol/kg wet weight), with similar reductions (P<0.01) in insulin sensitivity between the groups (Δ -44%: NS: 9.1±3.3 vs. IL: 5.1±1.8 mg/kg/min per μU/ml in AA) and (Δ -39%: NS: 12.9±6.0 vs. IL: 7.9±3.8 mg/kg/min per μU/ml in Caucasian) adolescents. CONCLUSIONS: In healthy adolescents, an acute elevation in plasma FFA with IL infusion is accompanied by significant increases in IMCL and reductions in insulin sensitivity with no race differential. Our findings suggest that AA normal-weight adolescents are not more susceptible than Caucasians to FFA-induced IMCL accumulation and insulin resistance.Metabolism: clinical and experimental 11/2012; · 2.59 Impact Factor -
Article: Underestimating a serving size may lead to increased food consumption when using Canada's Food Guide.
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ABSTRACT: It is unclear whether Canadians accurately estimate serving sizes and the number of servings in their diet as intended by Canada's Food Guide (CFG). The objective of this study was to determine if participants can accurately quantify the size of 1 serving and the number of servings consumed per day. White, Black, South Asian, and East Asian adults (n = 145) estimated the quantity of food that constituted 1 CFG serving, and used CFG to estimate the number of servings that they consumed from their 24-h dietary recall. Participants estimated 1 serving size of vegetables and fruit (+43%) and grains (+55%) to be larger than CFG serving sizes (p ≤ 0.05); meat alternatives (-33%) and cheese (-31%) to be smaller than a CFG serving size (p ≤ 0.05); and chicken, carrots, and milk servings accurately (p > 0.05). Serving size estimates were positively correlated with the amount of food participants regularly consumed at 1 meal (p < 0.001). From their food records, all ethnicities estimated that they consumed fewer servings of vegetables and fruit (-15%), grains (-28%), and meat and alternatives (-14%) than they actually consumed, and more servings of milk and alternatives (+26%, p ≤ 0.05) than they actually consumed. Consequently, 68% of participants believed they needed to increase consumption by greater than 200 kcal to meet CFG recommendations. In conclusion, estimating serving sizes to be larger than what is defined by CFG may inadvertently lead to estimating that fewer servings were consumed and overeating if Canadians follow CFG recommendations without guidance. Thus, revision to CFG or greater public education regarding the dietary guidelines is warranted.Applied Physiology Nutrition and Metabolism 07/2012; 37(5):923-30. · 2.13 Impact Factor
