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1.
Obesity (Silver Spring) ; 19(5): 1083-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21372804

RESUMO

Obesity is a growing problem in the United States and throughout the world. It is a risk factor for many chronic diseases. The BMI has been used to assess body fat for almost 200 years. BMI is known to be of limited accuracy, and is different for males and females with similar %body adiposity. Here, we define an alternative parameter, the body adiposity index (BAI = ((hip circumference)/((height)(1.5))-18)). The BAI can be used to reflect %body fat for adult men and women of differing ethnicities without numerical correction. We used a population study, the "BetaGene" study, to develop the new index of body adiposity. %Body fat, as measured by the dual-energy X-ray absorptiometry (DXA), was used as a "gold standard" for validation. Hip circumference (R = 0.602) and height (R = -0.524) are strongly correlated with %body fat and therefore chosen as principal anthropometric measures on which we base BAI. The BAI measure was validated in the "Triglyceride and Cardiovascular Risk in African-Americans (TARA)" study of African Americans. Correlation between DXA-derived %adiposity and the BAI was R = 0.85 for TARA with a concordance of C_b = 0.95. BAI can be measured without weighing, which may render it useful in settings where measuring accurate body weight is problematic. In summary, we have defined a new parameter, the BAI, which can be calculated from hip circumference and height only. It can be used in the clinical setting even in remote locations with very limited access to reliable scales. The BAI estimates %adiposity directly.


Assuntos
Absorciometria de Fóton/métodos , Adiposidade , Gordura Intra-Abdominal/diagnóstico por imagem , Circunferência da Cintura , Relação Cintura-Quadril , Adolescente , Adulto , Idoso , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estados Unidos , Adulto Jovem
2.
Diabetes ; 60(2): 477-85, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21228310

RESUMO

OBJECTIVE: Metformin can decrease adiposity and ameliorate obesity-related comorbid conditions, including abnormalities in glucose homeostasis in adolescents, but there are few data evaluating the efficacy of metformin among younger children. Our objective was to determine whether metformin treatment causes weight loss and improves obesity-related comorbidities in obese children, who are insulin-resistant. RESEARCH DESIGN AND METHODS: This study was a randomized double-blind placebo-controlled trial consisting of 100 severely obese (mean BMI 34.6 ± 6.6 kg/m(2)) insulin-resistant children aged 6-12 years, randomized to 1,000 mg metformin (n = 53) or placebo (n = 47) twice daily for 6 months, followed by open-label metformin treatment for 6 months. All children and their parents participated in a monthly dietitian-administered weight-reduction program. RESULTS: Eighty-five percent completed the 6-month randomized phase. Children prescribed metformin had significantly greater decreases in BMI (difference -1.09 kg/m(2), CI -1.87 to -0.31, P = 0.006), body weight (difference -3.38 kg, CI -5.2 to -1.57, P < 0.001), BMI Z score (difference between metformin and placebo groups -0.07, CI -0.12 to -0.01, P = 0.02), and fat mass (difference -1.40 kg, CI -2.74 to -0.06, P = 0.04). Fasting plasma glucose (P = 0.007) and homeostasis model assessment (HOMA) insulin resistance index (P = 0.006) also improved more in metformin-treated children than in placebo-treated children. Gastrointestinal symptoms were significantly more prevalent in metformin-treated children, which limited maximal tolerated dosage in 17%. During the 6-month open-label phase, children treated previously with placebo decreased their BMI Z score; those treated continuously with metformin did not significantly change BMI Z score further. CONCLUSIONS: Metformin had modest but favorable effects on body weight, body composition, and glucose homeostasis in obese insulin-resistant children participating in a low-intensity weight-reduction program.


Assuntos
Composição Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Metformina/uso terapêutico , Obesidade/tratamento farmacológico , Criança , Método Duplo-Cego , Feminino , Humanos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Resistência à Insulina , Masculino , Metformina/farmacologia , Resultado do Tratamento
3.
J Clin Endocrinol Metab ; 94(12): 4828-34, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19837941

RESUMO

CONTEXT: Some studies suggest the presence of metabolic syndrome before adulthood may identify those at high risk for later cardiovascular morbidity, but there are few data examining the reliability of pediatric metabolic syndrome. OBJECTIVE: To examine the short- and long-term stability of pediatric metabolic syndrome. DESIGN: Metabolic syndrome was defined as having at least three of the following: waist circumference, blood pressure, and fasting serum triglycerides in the 90th or higher percentile for age/sex; high-density lipoprotein-cholesterol 10th or lower percentile for age/sex; and fasting serum glucose of at least 100 mg/dl. Short-term metabolic syndrome stability (repeated measurements within 60 d) was assessed in obese youth ages 6-17 yr. Long-term metabolic syndrome stability (repeated measurements more than 1.5 yr apart) was studied in 146 obese and nonobese children age 6-12 yr at baseline. PATIENTS AND SETTING: Convenience samples of obese and nonobese youth ages 6-17 yr participating in research studies were collected at a clinical research hospital. RESULTS: Short-term metabolic syndrome stability (repeat measurements performed 19.7 +/- 13.1 d apart) was assessed in 220 children. The diagnosis of metabolic syndrome was unstable in 31.6% of cases. At their short-term follow-up visit, incidence of metabolic syndrome among participants who did not have metabolic syndrome at baseline was 24%. In the long term (repeat measurements performed 5.6 +/- 1.9 yr apart), the diagnosis of metabolic syndrome was unstable in 45.5% of cases. CONCLUSIONS: Cutoff-point-based definitions for pediatric metabolic syndrome have substantial instability in the short and long term. The value of making a cutoff-point-based diagnosis of metabolic syndrome during childhood or adolescence remains in question.


Assuntos
Síndrome Metabólica/metabolismo , Adolescente , Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Peso Corporal/fisiologia , Criança , Estudos de Coortes , Feminino , Seguimentos , Humanos , Lipídeos/sangue , Masculino , Obesidade/metabolismo , Fatores de Risco , Triglicerídeos/sangue , Circunferência da Cintura
4.
Ann Intern Med ; 150(12): 821-9, W145-6, 2009 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-19528561

RESUMO

BACKGROUND: Some data suggest that increasing calcium intake may help prevent weight gain. OBJECTIVE: To test the hypothesis that calcium supplementation can prevent weight gain in persons who are overweight or obese. DESIGN: Randomized, placebo-controlled trial. Randomization was computer-generated, and allocation was assigned by pharmacy personnel who prepared intervention and placebo capsules. Participants, providers, and those who assessed outcomes were blinded to study group assignment. SETTING: Single research center. PARTICIPANTS: 340 overweight (body mass index [BMI], 25 to <30 kg/m(2)) and obese (BMI > or =30 kg/m(2)) adults (mean age, 38.8 years [SD, 10.5]). INTERVENTION: Calcium carbonate (elemental calcium, 1500 mg/d) (n = 170) or placebo (n = 170) with meals for 2 years. MEASUREMENTS: Changes in body weight and fat mass (primary outcomes). RESULTS: Seventy-five percent of participants completed the trial (78% received calcium; 73% received placebo). There were no statistically or clinically significant differences between the calcium and placebo groups in change in body weight (difference, 0.02 kg [95% CI, -1.64 to 1.69 kg]; P = 0.98), BMI (difference, 0.32 kg/m(2) [CI, -0.41 to 1.02 kg/m(2)]; P = 0.39), or body fat mass (difference, 0.39 kg [CI, -1.04 to 1.92 kg]; P = 0.55). Parathyroid hormone concentrations decreased in the calcium group compared with the placebo group (difference, -0.71 pmol/L [CI, -1.28 to -0.13 pmol/L]). LIMITATION: The study took place at a research center, and its sample was mostly women. CONCLUSION: Dietary supplementation with elemental calcium, 1500 mg/d, for 2 years had no statistically or clinically significant effects on weight in overweight and obese adults. Calcium supplementation is unlikely to have clinically significant efficacy as a preventive measure against weight gain in such patients.


Assuntos
Carbonato de Cálcio/administração & dosagem , Cálcio da Dieta/administração & dosagem , Suplementos Nutricionais , Obesidade/dietoterapia , Sobrepeso/dietoterapia , Adiposidade , Adolescente , Adulto , Idoso , Índice de Massa Corporal , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , Sensibilidade e Especificidade , Inquéritos e Questionários , Redução de Peso , Adulto Jovem
5.
Obesity (Silver Spring) ; 16(2): 428-34, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18239655

RESUMO

OBJECTIVE: African Americans (AAs) have less visceral and more subcutaneous fat than whites, thus the relationship of adiponectin and leptin to body fat and insulin sensitivity in AA may be different from that in whites. METHODS AND PROCEDURES: Sixty-nine non-diabetic AA (37 men and 32 women), aged 33 +/- 1 year participated. The percent fat was determined by dual-energy X-ray absorptiometry, abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) volume by computerized tomography (CT), and insulin sensitivity by homeostasis model assessment (HOMA). RESULTS: VAT was greater in men (1,619 +/- 177 cm(3) vs. 1,022 +/- 149 cm(3); P = 0.01); women had a higher percentage of body fat (34.1 +/- 1.4 vs. 24.0 +/- 1.2; P < 0.0001), adiponectin (15.8 +/- 1.2 microg/ml vs. 10.4 +/- 0.8 microg/ml; P = 0.0004) and leptin (23.2 +/- 15.8 ng/ml vs. 9.2 +/- 7.2 ng/ml; P < 0.0001). SAT and HOMA did not differ because of the sex. Adiponectin negatively correlated with VAT (r = -0.41, P < 0.05) in men, and with VAT (r = -0.55, P < 0.01), and SAT (r = -0.35, P < 0.05) in women. Adiponectin negatively correlated with HOMA in men (r = -0.38, P < 0.05) and women (r = -0.44, P < 0.05). In multiple regression, sex (P = 0.02), HOMA (P = 0.03) and VAT (P = 0.003) were significant predictors of adiponectin (adj R (2) = 0.38, P < 0.0001). Leptin positively correlated with VAT, SAT, percent fat and HOMA in men (r = 0.79, r = 0.86, r = 0.89, and r = 0.53; P < 0.001) and women (r = 0.62, r = 0.75, r = 0.83, and r = 0.55; P < 0.01). In multiple regression VAT (P = 0.04), percent body fat (P < 0.0001) and sex (P = 0.01), but not HOMA were significant predictors of serum leptin (adj R (2)= 0.82, P < 0.0001). DISCUSSION: The relationship of adiponectin and leptin to body fat content and distribution in AA is dependent on sex. Although VAT and insulin sensitivity are significant determinants of adiponectin, VAT and percent body fat determine leptin.


Assuntos
Adiponectina/sangue , Tecido Adiposo/metabolismo , Negro ou Afro-Americano , Leptina/sangue , Tecido Adiposo/patologia , Adulto , Negro ou Afro-Americano/etnologia , Feminino , Humanos , Resistência à Insulina/fisiologia , Gordura Intra-Abdominal/metabolismo , Gordura Intra-Abdominal/patologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Análise de Regressão , Caracteres Sexuais , Gordura Subcutânea/metabolismo , Gordura Subcutânea/patologia
6.
Obesity (Silver Spring) ; 16(4): 841-6, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18292752

RESUMO

Total body size and central fat distribution are important determinants of insulin resistance. The BMI and waist circumference (WC) thresholds in African Americans that best predict insulin resistance are unknown. Our goal was to determine the BMI and WC values in African Americans, which optimally predict insulin resistance. The subjects were African Americans (68 men, 63 women), aged 35 +/- 8 years (mean +/- s.d.), with a BMI of 30.9 +/- 7.5, in the range of 18.5-54.7 kg/m(2), and with a WC of 98 +/- 18, in the range of 69-173 cm. Insulin resistance was defined by the lowest tertile of the insulin sensitivity index (S(I)). The Youden index was calculated to determine the WC and BMI thresholds that predict insulin resistance with an optimal combination of sensitivity and specificity. In men the thresholds that optimally predicted insulin resistance were a BMI > or =30 kg/m(2) or a WC > or =102 cm. For women, insulin resistance was best predicted by a BMI > or =32 kg/m(2) or a WC > or =98 cm. In African Americans, insulin resistance (in men) was best predicted by a WC > or =102 cm, and in women by a WC > or =98 cm, or by a BMI value that fell in the obese category (men: > or =30 kg/m(2), women: > or =32 kg/m(2)).


Assuntos
Negro ou Afro-Americano/estatística & dados numéricos , Intolerância à Glucose/diagnóstico , Intolerância à Glucose/etnologia , Resistência à Insulina , Obesidade/diagnóstico , Obesidade/etnologia , Relação Cintura-Quadril , Adulto , Índice de Massa Corporal , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Sobrepeso/diagnóstico , Sobrepeso/etnologia , Valor Preditivo dos Testes , Sensibilidade e Especificidade
7.
J Am Diet Assoc ; 108(1): 145-8, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18156002

RESUMO

Hypoferremia is more prevalent in obese than nonobese adults, but the reason for this phenomenon is unknown. To elucidate the role dietary factors play in obesity-related hypoferremia, the intake of heme and nonheme iron and the intake of other dietary factors known to affect iron absorption were compared cross-sectionally from April 2002 to December 2003 in a convenience sample of 207 obese and 177 nonobese adults. Subjects completed 7-day food records, underwent phlebotomy for serum iron measurement, and had body composition assessed by dual-energy x-ray absorptiometry, during a 21-month period. Data were analyzed by analysis of covariance and multiple linear regression. Serum iron (mean+/-standard deviation) was significantly lower in obese than nonobese individuals (72.0+/-61.7 vs 85.3+/-58.1 microg/dL [12.888+/-11.0443 vs 15.2687+/-10.3999 micromol/L]; P<0.001). The obese cohort reported consuming more animal protein (63.6+/-34.5 vs 55.7+/-32.5 g/day; P<0.001) and more heme iron (3.6+/-2.8 vs 2.7+/-2.6 mg/day; P<0.001). Groups did not differ, however, in total daily iron consumption, including supplements. Obese subjects reported consuming less vitamin C (77.2+/-94.9 vs 91.8+/-89.5 mg/day; P=0.01), which may increase absorption of nonheme iron, and less calcium (766.2+/-665.0 vs 849.0+/-627.2 mg/day; P=0.038), which may decrease nonheme iron absorption, than nonobese subjects. Groups did not significantly differ in intake of other dietary factors that can impact absorption of iron, including phytic acid, oxalic acid, eggs, coffee, tea, zinc, vegetable protein, or copper. After accounting for demographic covariates and dietary factors expected to affect iron absorption, fat mass (P=0.007) remained a statistically significant negative predictor of serum iron. This cross-sectional, exploratory study suggests that obesity-related hypoferremia is not associated with differences in reported intake of heme and nonheme iron or intake of dietary factors that can affect iron absorption.


Assuntos
Ácido Ascórbico/administração & dosagem , Dieta , Deficiências de Ferro , Ferro da Dieta/farmacocinética , Ferro/sangue , Obesidade/sangue , Absorciometria de Fóton , Tecido Adiposo/metabolismo , Adulto , Antioxidantes/administração & dosagem , Antioxidantes/metabolismo , Ácido Ascórbico/farmacologia , Composição Corporal/fisiologia , Cálcio da Dieta/administração & dosagem , Cálcio da Dieta/farmacologia , Estudos Transversais , Registros de Dieta , Feminino , Humanos , Absorção Intestinal/efeitos dos fármacos , Absorção Intestinal/fisiologia , Ferro da Dieta/administração & dosagem , Ferro da Dieta/metabolismo , Masculino , Avaliação Nutricional , Obesidade/metabolismo
8.
Arch Intern Med ; 167(21): 2329-36, 2007 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-18039992

RESUMO

BACKGROUND: An increased prevalence of low bone mineral density (BMD) has been reported in patients with major depressive disorder (MDD), mostly women. METHODS: Study recruitment was conducted from July 1, 2001, to February 29, 2003. We report baseline BMD measurements in 89 premenopausal women with MDD and 44 healthy control women enrolled in a prospective study of bone turnover. The BMD was measured by dual-energy x-ray absorptiometry at the spine, hip, and forearm. Mean hourly levels of plasma 24-hour cytokines, 24-hour urinary free cortisol, and catecholamine excretion were measured in a subset of women. We defined MDD according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition). RESULTS: The prevalence of low BMD, defined as a T score of less than -1, was greater in women with MDD vs controls at the femoral neck (17% vs 2%; P = .02) and total hip (15% vs 2%; P = .03) and tended to be greater at the lumbar spine (20% vs 9%; P = .14). The mean +/- SD BMD, expressed as grams per square centimeters, was lower in women with MDD at the femoral neck (0.849 +/- 0.121 vs 0.866 +/- 0.094; P = .05) and at the lumbar spine (1.024 +/- 0.117 vs 1.043 +/- 0.092; P = .05) and tended to be lower at the radius (0.696 +/- 0.049 vs 0.710 +/- 0.055; P = .07). Women with MDD had increased mean levels of 24-hour proinflammatory cytokines and decreased levels of anti-inflammatory cytokines. CONCLUSIONS: Low BMD is more prevalent in premenopausal women with MDD. The BMD deficits are of clinical significance and comparable in magnitude to those resulting from established risk factors for osteoporosis, such as smoking and reduced calcium intake. The possible contribution of immune or inflammatory imbalance to low BMD in premenopausal women with MDD remains to be clarified.


Assuntos
Densidade Óssea , Transtorno Depressivo/fisiopatologia , Pré-Menopausa/fisiologia , Absorciometria de Fóton , Adulto , Doenças Ósseas/etiologia , Doenças Ósseas/fisiopatologia , Catecolaminas/urina , Transtorno Depressivo/complicações , Transtorno Depressivo/diagnóstico , Feminino , Humanos , Hidrocortisona/urina , Interleucina-10/sangue , Interleucina-13/sangue , Interleucina-1beta/sangue , Interleucina-2/sangue , Interleucina-6/sangue , Pré-Menopausa/sangue , Pré-Menopausa/urina , Estudos Prospectivos , Fator de Necrose Tumoral alfa/sangue
9.
J Am Diet Assoc ; 107(5): 752-9, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17467370

RESUMO

OBJECTIVE: To assess the accuracy of three self-administered food frequency questionnaires (FFQs) to measure dietary calcium intake in healthy adults. DESIGN: Estimates of dietary calcium intake from one previously validated and two recently developed FFQs were compared with those from 7-day food records. SUBJECTS/SETTING: Healthy adults enrolled in an outpatient study of calcium supplementation completed the 36-page Dietary History Questionnaire (DHQ), a 3-page Calcium Questionnaire, and a 1-page Short Calcium Questionnaire. Subjects then completed a 7-day food record. MAIN OUTCOME MEASURES: Differences between calcium intake reported on FFQs and calcium intake from food records were compared. STATISTICAL ANALYSES: Spearman correlations were used to measure associations among variables; Bland-Altman pairwise comparisons were conducted to assess systematic and magnitude biases. RESULTS: We studied 341 subjects, 74.5% female, mean (+/-standard deviation) age of 38+/-11 years and body mass index (calculated as kg/m(2)) of 31.8+/-7.1. Mean (+/-standard deviation) food record calcium intake was 896+/-380 mg/day; data from all three FFQs were positively related to food record calcium intake, but accounted for <40% of the variance in food record dietary calcium intake (DHQ: r(2)=0.21; Calcium Questionnaire: r(2)=0.33; Short Calcium Questionnaire: r(2)=0.37; all P<0.001). The DHQ underestimated daily calcium intake (systematic bias: -94 mg/day, P<0.001; magnitude bias r=-0.40; P<0.001), whereas the Calcium Questionnaire overestimated calcium intake (systematic bias +177 mg/day, P<0.001), but had no significant magnitude bias (r=-0.09; P=0.11). The Short Calcium Questionnaire showed minimal systematic bias (+34 mg/day, P=0.09), but had magnitude bias (r=-0.33; P<0.001). CONCLUSIONS: All three FFQs performed reasonably well at estimating dietary calcium intake compared to food records; each may be appropriate for use in select clinical and research settings.


Assuntos
Cálcio da Dieta/administração & dosagem , Avaliação Nutricional , Autorrevelação , Inquéritos e Questionários/normas , Adulto , Idoso , Índice de Massa Corporal , Registros de Dieta , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Classe Social , Estatísticas não Paramétricas
10.
Clin Endocrinol (Oxf) ; 64(5): 523-9, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16649971

RESUMO

CONTEXT: Both obesity (body mass index, BMI > or = 30 kg/m2) and Black race are associated with a higher risk of vitamin D deficiency and secondary hyperparathyroidism. We hypothesized the risk of hypovitaminosis D would therefore be extraordinarily high in obese Black adults. OBJECTIVE: To study the effects of race and adiposity on 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (iPTH). DESIGN, SETTING AND PARTICIPANTS: Cross-sectional study of 379 Black and White adults from the Washington D.C. area. BMI ranged from 19.9 to 58.2 kg/m2. MAIN OUTCOME MEASURES: Prevalence of hypovitaminosis D [25(OH)D < 37.5 nmol/l] and secondary hyperparathyroidism [25(OH)D < 37.5 nmol/l with iPTH > 4.2 pmol/l]. RESULTS: Obese Black subjects had lower mean 25(OH)D, 40.3 (SD, 20.3) nmol/l, compared with obese Whites, 64.5 (29.7), P < 0.001, nonobese Blacks, 53.3 (26.0), P = 0.0025 and nonobese Whites, 78.0 (33.5), P < 0.001. The prevalence of hypovitaminosis D increased with increasing BMI, and was greater (P < 0.001) in Blacks than Whites within all BMI categories examined. Among subjects with BMI > or = 35 kg/m2, 59% of Blacks vs 18% of Whites had hypovitaminosis D (odds ratio 6.5, 95% confidence interval 3.0-14.2). iPTH was negatively correlated with 25(OH)D (r = -0.31, P < 0.0001), suggesting those with hypovitaminosis D had clinically important vitamin D deficiency with secondary hyperparathyroidism. For secondary hyperparathyroidism 35.2% of Blacks met the criteria, compared to 9.7% of Whites (OR 3.6, CI 1.5-98.8). CONCLUSIONS: Obese Black Americans are at particularly high risk for vitamin D deficiency and secondary hyperparathyroidism. Physicians should consider routinely supplementing such patients with vitamin D or screening them for hypovitaminosis D.


Assuntos
Negro ou Afro-Americano , Hiperparatireoidismo Secundário/etnologia , Obesidade/etnologia , Deficiência de Vitamina D/etnologia , Adulto , Idoso , Estudos Transversais , Registros de Dieta , Feminino , Humanos , Hiperparatireoidismo Secundário/sangue , Hiperparatireoidismo Secundário/complicações , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Obesidade/sangue , Obesidade/complicações , Prevalência , Vitamina D/análogos & derivados , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/complicações , População Branca
11.
Diabetes ; 54(9): 2663-7, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16123355

RESUMO

Both human linkage studies and MC3R knockout mouse models suggest that the MC3R may play an important role in energy homeostasis. Here we show that among 355 overweight and nonoverweight children, 8.2% were double homozygous for a pair of missense MC3R sequence variants (Thr6Lys and Val81Ile). Such children were significantly heavier (BMI and BMI SD score: P < 0.0001), had more body fat (body fat mass and percentage fat mass: P < 0.001), and had greater plasma leptin (P < 0.0001) and insulin concentrations (P < 0.001) and greater insulin resistance (P < 0.008) than wild-type or heterozygous children. Both sequence variants were more common in African-American than Caucasian children. In vitro expression studies found the double mutant MC3R was partially inactive, with significantly fewer receptor binding sites, decreased signal transduction, and less protein expression. We conclude that diminished MC3R expression in this double MC3R variant may be a predisposing factor for excessive body weight gain in children.


Assuntos
Obesidade/genética , Receptor Tipo 3 de Melanocortina/genética , Tecido Adiposo , Adolescente , Negro ou Afro-Americano/genética , Peso Corporal/genética , Criança , Pré-Escolar , Feminino , Expressão Gênica , Ligação Genética , Genótipo , Humanos , Insulina/sangue , Insulina/genética , Leptina/sangue , Leptina/genética , Masculino , Mutação de Sentido Incorreto , Polimorfismo Genético , População Branca/genética
12.
Obes Res ; 12(8): 1352-9, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15340119

RESUMO

OBJECTIVE: The contribution of visceral adipose tissue (VAT) to insulin resistance is well-established; however, the role of subcutaneous abdominal adipose tissue (SAT) in insulin resistance remains controversial. Sex may determine which of these two components of abdominal obesity is more strongly related to insulin resistance and its consequences. The aim of this study was to determine whether both VAT and SAT contribute to insulin resistance in African Americans and to examine the effects of sex on this relationship. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional study of 78 nondiabetic African-American volunteers (44 men, 35 women; age 33.8 +/- 7.3 years; BMI 30.9 +/- 7.4 kg/m2). VAT and SAT volumes were measured using serial computerized tomography slices from the dome of the diaphragm to the iliac crest. The insulin sensitivity index (SI) was determined from the minimal model using data obtained from the frequently sampled intravenous glucose tolerance test. RESULTS: In men, both VAT and SAT were negatively correlated with SI (r for both correlations = -0.57; p < 0.01). In women, the correlation coefficient between VAT and SI was -0.50 (p < 0.01) and between SAT and SI was -0.67 (p < 0.01). In women, the correlation coefficient for SI with SAT was significantly greater than the correlation coefficient with VAT (p = 0.02). DISCUSSION: Both SAT and VAT are strongly correlated with insulin resistance in African Americans. For African-American women, SAT may have a greater effect than VAT on insulin resistance.


Assuntos
Tecido Adiposo , População Negra , Composição Corporal , Resistência à Insulina , Tela Subcutânea , Vísceras , Adulto , Índice de Massa Corporal , Feminino , Intolerância à Glucose/epidemiologia , Teste de Tolerância a Glucose , Humanos , Masculino , Obesidade/epidemiologia , Análise de Regressão , Caracteres Sexuais , Tomografia Computadorizada por Raios X
13.
Am J Clin Nutr ; 80(1): 64-9, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15213029

RESUMO

BACKGROUND: Little is known about how simpler and more available methods to measure change in body fatness compare with criterion methods such as dual-energy X-ray absorptiometry (DXA) in children. OBJECTIVE: Our objective was to determine the ability of air-displacement plethysmography (ADP) and formulas based on triceps skinfold thickness (TSF) and bioelectrical impedance analysis (BIA) to estimate changes in body fat over time in children. DESIGN: Eighty-six nonoverweight and overweight boys (n = 34) and girls (n = 52) with an average age of 11.0 +/- 2.4 y underwent ADP, TSF measurement, BIA, and DXA to estimate body fatness at baseline and 1 +/- 0.3 y later. Recent equations were used to estimate percentage body fat by TSF measurement (Dezenberg equation) and by BIA (Suprasongsin and Lewy equations). Percentage body fat estimates by ADP, TSF measurement, and BIA were compared with those by DXA. RESULTS: All methods were highly correlated with DXA (P < 0.001). No mean bias for estimates of percentage body fat change was found for ADP (Siri equation) compared with DXA for all subjects examined together, and agreement between body fat estimation by ADP and DXA did not vary with race or sex. Magnitude bias was present for ADP relative to DXA (P < 0.01). Estimates of change in percentage body fat were systematically overestimated by BIA equations (1.37 +/- 6.98%; P < 0.001). TSF accounted for only 13% of the variance in percentage body fat change. CONCLUSION: Compared with DXA, there appears to be no noninvasive and simple method to measure changes in children's percentage body fat accurately and precisely, but ADP performed better than did TSF or BIA. ADP could prove useful for measuring changes in adiposity in children.


Assuntos
Tecido Adiposo/metabolismo , População Negra , Composição Corporal , Obesidade/metabolismo , População Branca , Absorciometria de Fóton/métodos , Absorciometria de Fóton/normas , Adolescente , Ar , Criança , Impedância Elétrica , Feminino , Humanos , Estudos Longitudinais , Masculino , Pletismografia/métodos , Pletismografia/normas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Dobras Cutâneas
14.
J Pediatr Endocrinol Metab ; 17(3): 307-19, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15112907

RESUMO

This pilot study compared the efficacy of orlistat as an adjunctive treatment for obesity between African American and Caucasian adolescents. Twenty obese adolescents with obesity-related co-morbid conditions underwent measurements of body composition, glucose homeostasis by frequently sampled intravenous glucose tolerance test (FSIGT), and fasting lipids before and after 6 months treatment with orlistat 120 mg tid in conjunction with a comprehensive behavioral program. Weight (p < 0.05), BMI (p < 0.001), total cholesterol (p < 0.001), LDL cholesterol (p < 0.001), fasting insulin (p < 0.02) and fasting glucose (p < 0.003) were lower after treatment. Insulin sensitivity, measured during the FSIGT, improved significantly (p < 0.02), as did fasting indices such as the homeostasis model assessment for insulin resistance (p < 0.01). African American subjects exhibited significantly less improvement in weight (p < 0.05), BMI (p < 0.01), waist circumference (p = 0.03), and insulin sensitivity (p = 0.05). Improvements in cholesterol were not significantly different between African Americans and Caucasians. We conclude that Caucasians lost more weight and had greater improvements in insulin sensitivity than African Americans, but both exhibited improvements in plasma lipids. The true benefit of orlistat treatment over a comprehensive behavioral program remains to be determined in placebo-controlled trials.


Assuntos
Terapia Comportamental/métodos , Negro ou Afro-Americano , Lactonas/uso terapêutico , Obesidade/tratamento farmacológico , Resultado do Tratamento , População Branca , Administração Oral , Adolescente , Glicemia/química , Glicemia/efeitos dos fármacos , Glicemia/fisiologia , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Cápsulas , LDL-Colesterol/sangue , LDL-Colesterol/efeitos dos fármacos , Ensaios Clínicos como Assunto , Comorbidade , Esquema de Medicação , Metabolismo Energético/efeitos dos fármacos , Feminino , Humanos , Resistência à Insulina/fisiologia , Lactonas/metabolismo , Lactonas/farmacologia , Leptina/sangue , Leptina/fisiologia , Masculino , Obesidade/sangue , Obesidade/complicações , Orlistate , Projetos Piloto
15.
Am J Clin Nutr ; 76(5): 975-9, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12399268

RESUMO

BACKGROUND: Men are believed to have more visceral adipose tissue (VAT) than women have, but studies in African Americans that measured VAT from a single computed tomography (CT) slice found no sex difference. OBJECTIVE: We used a serial-slice CT scan to investigate whether there is a sex difference in VAT volume among African Americans. DESIGN: Single-slice CT measurements of VAT area at lumbar spine L2-3 and L4-5 levels were taken in 110 African Americans (44 men, 66 women). In 59 subjects (24 men, 35 women), VAT volume was also measured with contiguous CT slices from the diaphragm to the iliac crest. Fat mass was determined by dual-energy X-ray absorptiometry. RESULTS: Men and women had similar ages (x +/- SD: 36.1 +/- 7.8 and 35.6 +/- 7.8 y, respectively) and body mass indexes in kg/m(2) (29.5 +/- 6.9 and 32.0 +/- 8.9). The percentage of body fat was lower (P < 0.0001) in men (21.8 +/- 7.3%) than in women (37.4 +/- 7.9%). The VAT volume was greater (P = 0.01) in men (1443 +/- 931 cm(3)) than in women (940 +/- 821 cm(3)). There was no sex difference in unadjusted VAT area at L2-3 (men, 88.6 +/- 63.5 cm(2); women, 57.2 +/- 45.4 cm(2)) or L4-5 (men, 65.6 +/- 53.3 cm(2); women, 55.0 +/- 38.3 cm(2)). After adjustment for percentage of body fat or fat mass, men had larger VAT area at both levels (P < 0.01). After adjustment for body mass index, the sex difference in VAT area was detectable at L2-3 (P < 0.001) but not at L4-5 (P = 0.22). CONCLUSIONS: VAT volume is greater in men than in women. Detection of sex differences in VAT area among African Americans on single-slice CT requires adjustment for body fat content. At L2-3, adjustment for body mass index alone is adequate to detect sex differences in VAT.


Assuntos
Absorciometria de Fóton , Tecido Adiposo/diagnóstico por imagem , População Negra , Caracteres Sexuais , Tomografia Computadorizada por Raios X , Vísceras/diagnóstico por imagem , Negro ou Afro-Americano , Feminino , Humanos , Masculino
16.
Obes Res ; 10(7): 642-50, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12105286

RESUMO

OBJECTIVE: To study the safety, tolerability, and potential efficacy of orlistat in adolescents with obesity and its comorbid conditions. RESEARCH METHODS AND PROCEDURES: We studied 20 adolescents (age, 14.6 +/- 2.0 years; body mass index, 44.1 +/- 12.6 kg/m(2)). Subjects were evaluated before and after taking orlistat (120 mg three times daily) and a multivitamin for 3 months. Subjects were simultaneously enrolled in a 12-week program emphasizing diet, exercise, and strategies for behavior change. RESULTS: Participants who completed treatment (85%) reported taking 80% of prescribed medication. Adverse effects were generally mild, limited to gastrointestinal effects observed in adults, and decreased with time. Three subjects required additional vitamin D supplementation despite the prescription of a daily multivitamin containing vitamin D. Weight decreased significantly (-4.4 +/- 4.6 kg, p < 0.001; -3.8 +/- 4.1% of initial weight), as did body mass index (-1.9 +/- 2.5 kg/m(2); p < 0.0002). Total cholesterol (-21.3 +/- 24.7 mg/dL; p < 0.001), low-density lipoprotein-cholesterol (-17.3 +/- 15.8 mg/dL; p < 0.0001), fasting insulin (-13.7 +/- 19.0 microU/mL; p < 0.02), and fasting glucose (-15.4 +/- 7.4 mg/dL; p < 0.003) were also significantly lower after orlistat. Insulin sensitivity, assessed by a frequently sampled intravenous glucose-tolerance test, improved significantly (p < 0.02). DISCUSSION: We conclude that, in adolescents, short-term treatment with orlistat, in the context of a behavioral program, is well-tolerated and has a side-effect profile similar to that observed in adults, but its true benefit versus conventional therapy remains to be determined in placebo-controlled trials.


Assuntos
Lactonas/efeitos adversos , Lactonas/uso terapêutico , Obesidade/tratamento farmacológico , Adolescente , Glicemia/análise , Índice de Massa Corporal , Colesterol/sangue , LDL-Colesterol/sangue , Suplementos Nutricionais , Jejum , Feminino , Teste de Tolerância a Glucose , Humanos , Insulina/sangue , Masculino , Obesidade/sangue , Obesidade/complicações , Orlistate , Projetos Piloto , Resultado do Tratamento , Vitamina D/administração & dosagem , Vitaminas/administração & dosagem , Redução de Peso
17.
Int J Eat Disord ; 31(4): 430-41, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-11948648

RESUMO

OBJECTIVE: To investigate the relationship between loss of control over eating, adiposity, and psychological distress in a nontreatment sample of overweight children. METHOD: Based on self-reports of eating episodes, 112 overweight children, 6-10 years old, were categorized using the Questionnaire of Eating and Weight Patterns-Adolescent Version into those describing episodes of loss of control over eating (LC), and those with no loss of control (NoLC). Groups were compared on measures of adiposity, dieting, and eating behavior, and associated psychological distress. RESULTS: LC children (33.1%) were heavier and had greater amounts of body fat than NoLC children. They also had higher anxiety, more depressive symptoms, and more body dissatisfaction. 5.3% met questionnaire criteria for BED. Episodes of loss of control occurred infrequently, were often contextual, and involved usual meal foods. DISCUSSION: As in adults, overweight children reporting loss of control over eating have greater severity of obesity and more psychological distress than those with no such symptoms. It remains unknown whether children who endorse loss of control over eating before adolescence will be those who develop the greatest difficulties with binge eating or obesity in adulthood.


Assuntos
Bulimia/complicações , Controle Interno-Externo , Obesidade/psicologia , Estresse Psicológico/complicações , Análise de Variância , Imagem Corporal , Índice de Massa Corporal , Criança , Ingestão de Energia , Feminino , Humanos , Masculino , Maryland
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