Search

(YGd)(VP)AlO:0.06Eu (0 ≤ x ≤ 1.0 and 0 ≤ y ≤ 0.02) phosphors are synthesized by the solution combustion process. In this study, structural and photoluminescence properties of the (YGd)(VP)AlyO:0.06Eu phosphors are reported. The emission characteristics of the (YGd)VO:0.06Eu phosphor under vacuum ultraviolet (VUV) excitation are greatly improved with the incorporation of Al ions and partial substitution of P for V. The red emission intensity of the (YGd)(VP)AlO:0.06Eu phosphor is 151% stronger than that of the (YGd)(V0.25P0.75)O:0.06Eu phosphor. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Background/objectives: The relationship between obesity and circulating levels of antioxidants is poorly understood. Most studies that have examined the association of adiposity with blood or tissue concentrations of antioxidant micronutrients have been cross-sectional, and few have compared the associations for indices of overall obesity and central obesity. Our aim was to prospectively examine the longitudinal association of body mass index (BMI), waist circumference (WC), waist circumference-height ratio (WCHtR) and waist-hip ratio (WHR) with major serum antioxidants in a population of postmenopausal women.Subjects/methods: We used a subsample of participants in the Women's Health Initiative aged 50-79 years at entry with available fasting blood samples and anthropometric measurements obtained at multiple time points over 12.8 years of follow-up (N=2672). Blood samples were used to measure α-carotene, β-carotene, β-cryptoxanthin, lutein+zeaxanthin, α-tocopherol, γ-tocopherol and retinol at baseline, and at years 1, 3 and 6. We used mixed-effects linear regression analyses to examine associations between anthropometric measures and serum antioxidants at baseline and over time, controlling for covariates.Results: In longitudinal analyses, carotenoids, and particularly β-carotene, were strongly and inversely associated with BMI, WC and WCHtR and less so with WHR. α-Tocopherol showed a strong positive association with WHR but not with other anthropometric measures, whereas γ-tocopherol was positively and strongly associated with BMI, WC, WCHtR and less so with WHR. Retinol was positively associated with WHR. The inverse association of several carotenoids with anthropometric measures was stronger in never and former smokers compared with current smokers and in women without the metabolic syndrome. The inverse association of carotenoids with obesity measures may reflect reduced micronutrient concentrations owing to inflammation associated with obesity.Conclusions: In the present study, the strongest observed associations between anthropometric variables and micronutrients were an inverse association of WC with serum β-carotene and a positive association of WC with γ-tocopherol. [ABSTRACT FROM AUTHOR]

Objective:Four body mass index (BMI) metrics-BMI, BMI z-score, BMI percentile and BMI%-are commonly used as proxy measures for children's adiposity. We sought to determine a BMI metric that is most strongly associated with measured percentage of body fat (%BF) in the US pediatric population stratified by sex, age and race/ethnicity, and to determine cutoffs that maximize the association for each BMI metric.Subjects, Design and Methods:%BF was measured by dual-energy X-ray absorptiometry among N=6120 US boys and girls aged 8.0-17.9 years old from the National Health and Nutrition Examination Survey 1999-2004. We fit piecewise linear regression models with cutoffs to %BF data using each BMI metric as the predictor stratified by sex, race/ethnicity and age. The slopes were modeled differently before and after the cutoffs which were determined on the basis of grid searches.Results:BMI z-score was in general most strongly associated with %BF for both boys and girls. The associations of the four BMI metrics were lowest for boys aged 12-13.9 years and girls aged 16-17.9 years, and strongest for Mexican-American boys and for non-Hispanic Black girls. Overall, the associations were stronger for girls than for boys. In boys, BMI had the lowest association with %BF (R2=0.39) for all ages combined. The fold changes in slopes before and after cutoffs were greatest in general for BMI percentiles regardless of age, sex and race/ethnicity. BMI z-score cutoffs were 0.4 for both boys and girls for all ages combined. Except for BMI, the slopes after the cutoffs were in general greater than those before.Conclusions:All BMI metrics were strongly associated with %BF when stratified by age and race/ethnicity except that BMI was the least associated with %BF in boys for all ages combined. Overall, BMI z-score was superior for evaluation of %BF, and its cutoff of 0.4 can also serve as a threshold for careful monitoring of weight status. [ABSTRACT FROM AUTHOR]

BACKGROUND:Body mass index (BMI; weight (Wt)/height (Ht) (in kg m−2) and waist circumference (WC) are widely used as proxy anthropometric measures for total adiposity. Little is known about what scaling power of 'x' in both Wt(kg)/Ht(m)x and WC(m)/Ht(m)x is maximally associated with measured total body fat mass (TBFM). Establishing values for x would provide the information needed to create optimum anthropometric surrogate measures of adiposity.OBJECTIVE:To estimate the value of 'x' that renders Wt/Htx and WC/Htx maximally associated with DXA-measured TBFM.SUBJECTS:Participants of the NHANES 1999-2004 surveys, stratified by sex (men, women), race/ethnicity (non-Hispanic whites, non-Hispanic blacks, Mexican-Americans), and age(18-29, 30-49, 50-84years).METHODS:We apply a grid search by increasing x from 0.0-3.0 by increments of 0.1 to the simple regression models, TBFM=b0+b1*(Wt/Htx) and TBFM=b0+b1*(WC/Htx) to obtain an estimate of x that results in the greatest R2, taking into account complex survey design features and multiply imputed data.RESULTS:R2's for BMI are 0.86 for men (N=6544) and 0.92 for women (N=6362). The optimal powers x for weight are 1.0 (R2=0.90) for men and 0.8 (R2=0.96) for women. The optimal power x for WC is 0, that is, no scaling of WC to height, for men (R2=0.90) or women (R2=0.82). The optimal powers for weight across nine combinations of race/ethnicity and age groups for each sex vary slightly (x=0.8-1.3) whereas the optimal scaling powers for WC are all 0 for both sexes except for non-Hispanic black men aged 18-29y (x=0.1). Although the weight-for-height indices with optimal powers are not independent of height, they yield more accurate TBFM estimates than BMI.CONCLUSION:In reference to TBFM, Wt/Ht and Wt/Ht0.8 are the optimal weight-for-height indices for men and women, respectively, whereas WC alone, without Ht adjustment, is the optimal WC-for-height index for both sexes. Thus, BMI, an index independent of height, may be less useful when predicting TBFM. [ABSTRACT FROM AUTHOR]

Objective:Body mass index (BMI) is the surrogate measure of adiposity most commonly employed in children and adults. Waist circumference (WC) and the waist circumference-to-height ratio (WCHt) have been proposed as markers of adiposity-related morbidity in children. However, no study to date has compared WCHt, WC, BMI and skinfolds thickness for their ability to detect body adiposity.Aim:To compare WCHt, WC, BMI and skinfolds for their accuracy in predicting percent body fat (PBF), percent trunk fat (PTF) and fat mass index (FMI) in a large sample of children and adolescents.Design, setting and participants:We studied 2339 children and adolescents aged 8-18 years from the US National Health and Nutrition Examination Survey 2003/2004. Body fat was measured using dual-energy X-ray absorptiometry. Multivariable regression splines were used to model the association between PBF, PTF, FMI and the predictors of interest.Results:WCHt alone explained 64% of PBF variance as compared with 31% for WC, 32% for BMI and 72% for the sum of triceps and subscapular skinfolds (SF2) (P<0.001 for all). When age and gender were added to the predictors, the explained variance increased to 80% for the WCHt model, 72% for the WC model, 68% for the BMI model and 84% for the SF2 model. There was no practical advantage to add the ethnic group as further predictor. Similar relationships were observed with PTF and FMI.Conclusions:WCHt is better than WC and BMI at predicting adiposity in children and adolescents. It can be a useful surrogate of body adiposity when skinfold measurements are not available. [ABSTRACT FROM AUTHOR]

Objective:Children differ greatly in their ability to self-regulate food intake for reasons that are poorly understood. This laboratory-based twin study tested the genetic and environmental contributions to self-regulatory eating and body fat in early childhood.Methods:A total of 69 4-7 year-old same-sex twin pairs, including 40 monozygotic and 29 dizygotic pairs, were studied. Self-regulatory eating was operationalized as the percentage compensation index (COMPX%), assessed by a 'preload' challenge in which lunch intake was measured following a low- (3 kcal) or high-calorie (159 kcal) drink. Body fat indexes also were measured. The familial association for COMPX% was estimated by an intraclass correlation, and biometric analyses estimated heritability.Results:Children ate more at lunch following the low- compared with high-energy preload (P<0.001), although variability in COMPX% was considerable. Compensation was significantly poorer among African American and Hispanic compared with European American children, and among girls compared with boys. There was a familial association for self-regulatory eating (ρ=0.23, P=0.03) but no significant genetic component. In all, 22% of the variance in COMPX% was due to shared environmental 'household' factors, with the remaining variance attributable to child-specific 'unique' or 'random' environments. Poorer self-regulatory eating was associated with greater percent body fat (r=−0.21, P=0.04).Conclusions:Self-regulatory eating was influenced by environmental factors, especially those differing among siblings. The absence of a significant genetic effect may reflect the age of the sample or could be artifactual due to measurement issues that need to be considered in future studies. [ABSTRACT FROM AUTHOR]

High-quality (GdZn)PO: xTb (0.06≤x≤0.15) green phosphors were synthesized by ultrasonic spray pyrolysis. With an increase of Tb content, the emission intensities caused by the D→ (J = 3, 4, 5, and 6) and D→F (J = 4, 5, and 6) transitions of Tb increased and decreased, respectively, allowing a purer green emission. The emission intensity of (GdZn)PO:0.15Tb at 544 nm was 53.0% stronger than that of (GdZn)PO:0.06Tb. The emission intensity and the green color purity were remarkably improved by increasing Tb content in (GdZn)PO: xTb. [ABSTRACT FROM AUTHOR]

Objective:Sustained depressive mood is a gateway symptom for a major depressive disorder. This paper investigated whether the association between depressive mood and obesity differs as function of sex, age, and race in US adults after controlling for socio-economic variables of martial status, employment status, income level and education level.Methods:A total of 44 800 nationally representative respondents from the 2001 Behavioral Risk Factor Surveillance Survey were studied. Respondents were classified as having experienced a depressive mood if they felt sad, blue, or depressed at least for 1 week in the previous month. The depressive mood was operationalized in terms of duration and sustenance, both defined based on number of days with depressive mood: 7+ and 14+ days. Age groups were classified as young (18–64 years) and old (65+ years). Obesity status was classified as: not overweight/obese (BMI<25); overweight (25BMI<30); obese (BMI30).Results:Prevalence of prior-month depressive mood was 14.3 and 7.8% for 7+ and 14+ days, respectively. Controlling for race and socio-economic variables, both young overweight and obese women were significantly more likely to have experienced depressive mood than nonoverweight/nonobese women. Young overweight, but not obese, men were significantly more likely to have experienced depressive mood than nonoverweight/nonobese men. Young obese women were also significantly more likely to have a sustained depressive mood than nonoverweight/nonobese women. For old respondents, depressive mood and its sustenance were not associated with obesity in either sex.Discussion:The relationship between the depressive mood and obesity is dependent upon gender, age, and race. Young obese women, Hispanics in particular, are much more prone to depressive mood than nonobese women. Future studies testing associations between depression and obesity should be sensitive to the influence of these demographic and socio-economic variables.International Journal of Obesity (2006) 30, 513–519. doi:10.1038/sj.ijo.0803122; published online 15 November 2005 [ABSTRACT FROM AUTHOR]

Background: Weight control programs for obese children monitor change in body mass index (BMI) adjusted for age. However, change can be measured in several ways: raw (kg/m2) units, percentage, z-scores or centiles. The suitability of the different measures is not known.Aim: To identify the optimal BMI measure for change, whose short-term variability is most consistent for children across the spectrum of adiposity.Setting: An Italian kindergarten.Subjects: A total of 135 (66 female) children aged 29-68 months at baseline, with BMI measured three times over a 9-month period.Methods: Each child's short-term variability in adiposity was summarized by the standard deviation (s.d.) of BMI and BMI % adjusted for age, and BMI z-score and BMI centile. The s.d.'s were then compared in obese and nonobese children, and also correlated with each child's baseline BMI z-score.Results: The within-child s.d.s of BMI z-score and BMI centile were significantly smaller in obese than nonobese children, while the s.d.s of BMI and BMI % were similar in the two groups. Also, the within-child s.d.s of z-score and centile, and to a lesser extent BMI %, were significantly inversely correlated with baseline z-score, whereas the s.d. of BMI was not. The changes in adiposity over time, as assessed by the four measures, were very highly correlated with each other, particularly for BMI with BMI %.Discussion: Even though BMI z-score is optimal for assessing adiposity on a single occasion, it is not necessarily the best scale for measuring change in adiposity, as the within-child variability over time depends on the child's level of adiposity. Better alternatives are BMI itself or BMI %. Our results underscore the importance of using a relatively stable method to assess adiposity change when following children at risk of obesity. [ABSTRACT FROM AUTHOR]

BACKGROUND: The energy content of weight change is assumed to be sex- and age-neutral at 3500 kcal/pound or 32.2 MJ/kg. OBJECTIVES: As sexual dimorphism in body composition generally exists in mammals, the primary hypothesis advanced and tested was that the energy content of weight change differs between men and women. DESIGN: The energy content of 129 adult men and 287 women was measured by neutron activation analysis. Cross-sectional energy content prediction models were developed and then evaluated in two longitudinal samples: one that used the same methods in 26 obese women losing weight; and the other a compilation of 18 previously reported weight change-body composition studies. RESULTS: Multiple regression modeling identified weight, sex, age and height as total energy content predictor variables with significant sex × weight (P < 0.001) and age × weight (P < 0.001) interactions; total model r² and s.e.e, were 0.89 and 107.3 MJ, respectively. The model's predictive value was supported in both longitudinal evaluation samples. Model calculations using characteristics of representative adults gaining or losing weight suggested that the energy content of weight change in women (∼ 30.1 - 32.2 MJ/kg) is near to the classical value of 32.2 MJ/kg and that in men the value is substantially lower, ∼21.823.8 MJ/kg. The predicted energy content of weight change increases by about 10% in older (age ∼ 70 y) vs younger (∼ 35 y) men and women. CONCLUSIONS: Sexual dimorphism and age-dependency appears to exist in the estimated energy content of weight change and these observations have important clinical and research implications. [ABSTRACT FROM AUTHOR]

METHOD: We analyzed data pooled from nine studies on the human leptin receptor (LEPR) gene for the association of three alleles (K109R, Q223R and K656N) of LEPR with body mass index (BMI; kg/m²) and waist circumference (WC). A total of 3263 related and unrelated subjects from diverse ethnic backgrounds including African-American, Caucasian, Danish, Finnish, French Canadian and Nigerian were studied. We tested effects of individual alleles, joint effects of alleles at multiple loci, epistatic effects among alleles at different loci, effect modification by age, sex, diabetes and ethnicity, and pleiotropic genotype effects on BMI and WC. RESULTS: We found that none of the effects were significant at the 0.05 level. Heterogeneity tests showed that the variations of the non-significant effects are within the range of sampling variation. CONCLUSION: We conclude that, although certain genotypic effects could be population-specific, there was no statistically compelling evidence that any of the three LEPR alleles is associated with BMI or WC in the overall population. [ABSTRACT FROM AUTHOR]

OBJECTIVE: As a result of efforts to isolate obesity-promoting genes, the Trp64Arg polymorphism in the β3 adrenergic receptor locus, has been studied by many investigators. Results of the studies have varied in statistical significance and magnitude of the association of the polymorphism with body mass index (BMI: kg/m2). This has led to controversy about whether this polymorphism is associated with meaningful changes in BMI. To clarify the possible association, we conducted a meta-analysis. DESIGN: Meta-analytic study. MEASUREMENTS: For each genotype of the β3 adrenergic receptor (Trp/Trp; Trp/Arg; Arg/Arg), we extracted the number of subjects, mean and standard deviation of BMI from 23 studies, including 36 different subgroups with a total of 7399 subjects. Other indices and obesity-related variables were not considered. RESULTS: No significant association of the Trp64Arg polymorphism with BMI was found. The weighted mean BMI difference beween Trp/Trp homozygotes and Trp/Arg heterozygotes was 0.19 (s.e.=0.11; P=0.07). In addition, the distribution of effect sizes was not significantly heterogeneous (χ2=38.68; df 35; P=0.31) suggesting that the variation of the effect sizes across the subgroups is not significant. A further weighted regression analysis, utilizing all three genotypes and adjusting for the random subgroup effect, also showed the effect of the polymorphism on BMI is not significant (F=1.72, df=(2,54), P=0.19). CONCLUSION: Based on existing data, the Trp64Arg polymorphism does not appear to be significantly associated with BMI. Moreover, we found no evidence for effect heterogeneity, suggesting that the effect of the polymorphism is not moderated by ethnicity or diabetic status. [ABSTRACT FROM AUTHOR]

Numerous weight loss trials show that maintenance of weight loss is extremely difficult to sustain over time in adulthood. Using general population sample of adults whose weights were longitudinally tracked across several decades, we quantified resistance of weight to change by means of body mass index autocorrelation across a series of paired time points. Equations for ageadjusted sex-specific body mass index autocorrelation were developed. We found that body weight is quite resistant to change over years and decades. This finding partially de-mystifies the weight regain observed following intervention that last weeks or months. [ABSTRACT FROM AUTHOR]