Biomedical subjects

D B Allison

Publications and source records attributed to D B Allison.

At least 145 records · Page 8Linked to original sources

PubMed1995

Decreased resting metabolic rate among persons with Down Syndrome.

OBJECTIVE: To compare the resting metabolic rates (RMRs) of adults with and without DS while controlling for potential confounds. DESIGN: Observational, cross-sectional study. SETTING: Outpatient core of the New York Obesity Research Center. SUBJECTS: Thirteen adults (nine males and four females) with DS were compared to 77 adults without DS. MEASUREMENTS: RMR was measured by indirect calorimetry. Fat mass (FM) and fat free mass (FFM) were determined using dual energy X-ray absorptiometry (DXA). Thyroid function (thyroxin, T3 uptake, and free T4) were determined from fasting blood samples for all DS subjects and a subset of the controls. RESULTS: An analysis of covariance was conducted in which DS status was the independent variable. Covariates were sex, FFM, FM, age, and T4. After controlling for sex, FFM, FM, age, and height, persons with DS had lower RMRs than persons without DS (F(1,83) = 7.697, P = 0.007; eta = 0.29). In terms of kcalories, the adjusted means were 1333.5 for DS subjects and 1670.1 for non-DS subjects, a difference of 20.8% relative to the grand mean. When thyroxine was added to the regression the effect of DS on RMR was of questionable significance. CONCLUSION: This research demonstrates that persons with DS have lower RMRs than do persons without DS. This difference persists after controlling for obvious confounds and was of a moderate magnitude.

Absorptiometry, Photon↗

PubMed1994

Columbia respiratory-chamber indirect calorimeter: a new approach to air-flow modelling.

A new air-flow modelling approach for respiratory-chamber indirect calorimetry is introduced. Based on thermodynamic theory, differential equations describing the dynamics of the calorimeter are derived. These equations are then developed into a linear state space model that can be conceptualized as a modern control system. Furthermore, both the system/output noises and input/output delays are considered in the model in the context of real applications. Finally, system accuracy is analysed so that the parameters in the calorimeter can be selected to minimise the error in estimating energy expenditure in humans.

Basal Metabolism↗

PubMed1994

A genetic analysis of relative weight among 4,020 twin pairs, with an emphasis on sex effects.

This study replicated previous findings showing a high heritability of obesity, as measured by body mass index (kg/m2), using a measure of relative weight that does not assume a constant regression of height on weight across different populations, and evaluated whether there are sex-limited genetic effects. Subjects were 4,020 adult twin pairs. Alternative causal structural equation models were fitted to variance-covariance matrices. The ADE model (additive genetic effects, dominant/nonadditive genetic effects, and unique environment) fit best. Allowing for sex-specific effects (common sex-limitation model) significantly improved the fit, X2(6) = 230.5, p < .001. The heritability of that portion of weight unrelated to height was large: .61 for men and .73 for women.

Adolescent↗

PubMed1994

Reduced risk of liver-function-test abnormalities and new gallstone formation with weight loss on 3350-kJ (800-kcal) formula diets.

Weight loss in obese subjects ingesting very-low-energy (VLE; < 2510 kJ/d), low-fat (< or = 1 g/d) formula diets is associated with liver-function-test abnormalities and gallstone formation. It is unknown whether these abnormalities develop during treatment with diets higher in energy and fat. We prospectively studied liver-function tests and gallstone formation in 73 obese patients ingesting approximately 3500 kJ and 15-25 g fat daily for 10 wk. Two of 53 patients completing the protocol developed ultrasonographic gallstones during weight loss, a rate substantially lower than that observed with VLE diets. Trend analysis demonstrated significant increases in AST and ALT activities, but changes were less than those observed with VLE diets. Patients who developed gallstones had a significantly greater weight loss rate and larger increases in AST and ALT than did nonstone-forming patients. These results suggest that the risk of developing hepatobiliary abnormalities with dieting is lowered when subjects ingest greater amounts of energy and fat than that administered in earlier VLE-diet studies. Our results also highlight potential risk factors and markers of new gallstone formation.

Adult↗

PubMed1994

Differences between young and old females in the five levels of body composition and their relevance to the two-compartment chemical model.

BACKGROUND: Body composition differs between young and old females, although the magnitude of these age-related changes remains uncertain. This uncertainty persists because methodology applied in earlier studies required assumptions that may be age-dependent and also because studies included young and old subjects who differed substantially in body size and health status. METHODS: To resolve these earlier concerns we examined components at the atomic, molecular, cellular, tissue-system, and whole body levels of body composition in 19 weight- and height-matched pairs of young (age 19-35 yrs) and old (age > 65 yrs) healthy White females. Isotope dilution, dual photon, whole-body counting, hydrodensitometry, and anthropometric methods were used either alone or in combination to produce multicomponent models. RESULTS: Old females had significantly more fat, greater truncal skinfolds and circumferences, and significantly less fat-free body mass (FFM), total body potassium (TBK), total body water (TBW), and bone mineral than did their young matched counterparts. Skeletal muscle mass was less in the old females, although the magnitude of the difference from young females varied between the three indices examined. The main assumptions (i.e., TBW/FFM = 0.73 kg/kg and density of FFM = 1.100 g/cc) which the widely used two-compartment TBW and hydrodensitometry methods are based on were not significantly different in young and old females. In contrast, the main assumed steady-state value for the two-compartment TBK method (TBK/FFM = 64.2 mmol/kg) was significantly lower (p < .001) in the old females. CONCLUSION: New approaches thus allow for a critical reexamination of body composition in elderly subjects, and these methods also give new insight into less complex widely used body composition techniques.

Adipose Tissue↗

PubMed1994

On constructing the disorder of hysteria.

The concept of hysteria is traced from Hippocrates, where it was though to be caused by a wandering uterus, through Galen and up to Freud. Throughout the history of medicine from the early Greeks up to the end of the nineteenth century, the definition and diagnosis of hysteria had a function similar to that found in the persecution of witchcraft: it sought to eradicate the outbursts of nonconforming and emotionally threatening conduct of women. At the beginning of the twentieth century, however, the category virtually disappears from psychiatric nosologies.

Attitude to Health↗

PubMed1994

Race effects in the genetics of adolescents' body mass index.

Although the genetics of relative weight have been investigated in several studies, most of these have been done primarily, if not exclusively, with whites. This study examined the heritability of body mass index (BMI) in 238 pairs of adolescent black and white male and female twins. BMIs were residualized for age and transformed to approximate normality. Hierarchically nested structural equation models were tested. An AE model (A = additive gene effects, E = unique environmental influences) in which the degree to which genetic and environmental factors influence BMI varies by race provided the best fit. Both the genotype and the environment exerted a greater influence on the BMI of black than white adolescents. Thus, although the variances in BMI are greater for blacks, the heritabilities were the same for blacks and whites. Implications for future research are discussed.

Adolescent↗

PubMed1994

Body composition and two-compartment model assumptions in male long distance runners.

Long distance running increases bone mineral mass, skeletal muscle weight, and extracellular fluid volume. Each of these changes may have an impact on classic two-compartment body composition methods that assume a constant fat-free body mass (FFM) density (1.100 g.cc-1), potassium content (65 mmol.kg-1 FFM), and hydration (0.73 kg H2O.kg-1 FFM). The aims of the present study were: to use newly developed multi-component methods to evaluate the validity of two-compartment methods in white male recreational long-distance runners (N = 10); and to compare the body composition of these runners to sedentary controls (N = 10) of similar age, body weight, and body mass index. Runners had a significantly smaller fraction of body weight as fat (P = 0.001) and a larger fraction of FFM as lower extremity skeletal muscle (P = 0.045) and bone (P = 0.049). Although FFM constituted a larger proportion of body weight in the runners, the fractional contributions of water, protein, and mineral were similar to those in the control group. There were no significant differences between the two groups in density of FFM, total body potassium/FFM, and total body water/FFM. New methods thus allow in-depth analyses of body composition in athletes, with results suggesting that classic two-compartment methods are valid in white recreational long-distance runners.

Absorptiometry, Photon↗

PubMed1993

Evidence of a major gene with pleiotropic action for a cardiovascular disease risk syndrome in children younger than 14 years.

OBJECTIVE: To test the plausibility of the existence of a genetically based syndrome involving obesity, hypertension, and a central deposition of body fat. DESIGN: Survey of a random stratified sample of the US population. PARTICIPANTS: Male and female children aged 13 years or younger (mean, 5.3 years; SD, 3.7 years; median, 4.0 years; range, 6 months to 13 years) were chosen from National Health and Nutrition Examination Survey II data. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: Using multivariate commingling analysis, we evaluated the hypothesis that a major gene produces a syndrome involving the phenotypic indicators of body mass index (in kilograms per square meter), subscapular-to-triceps skinfold thickness ratio, systolic blood pressure, and diastolic blood pressure. Maximum likelihood estimation was used to test competing models. A model with three component distributions and unequal variance-covariance matrices fit significantly better than any competing model. CONCLUSIONS: Our findings support the existence of a distinct cardiovascular disease risk syndrome in children and suggest that it may be the result of a major gene with pleiotropic effects.

Adolescent↗

PubMed1993

Toward an empirically derived typology of obese persons: derivation in a nonclinical sample.

The purpose of this research was to empirically derive a typology of obese persons and validate a typology derived in earlier research (Allison & Heshka [1991] International Journal of Obesity). Biological, behavioral, and psychological variables were assessed through survey among 719 (641 females, 78 males) obese members of The National Association to Advance Fat Acceptance (NAAFA). All variables were subjected to principal components analyses which extracted 12 biological and 12 psychological components. A two-cluster solution from a k-means clustering on biological components was replicated via Ward's method. Agreement between the solutions was significant (Phi = .33, Kappa = .19, p < .05). The solution was validated through entering psychological component scores into discriminant analysis. One significant function (p < .001) substantially separated the clusters. A component measuring early onset/familial history powerfully discriminated between the clusters. Early onset obese were more obese, more active, and restricted caloric intake to a greater degree. Late onset obese were more likely to be "settled down," engage in substance abuse, eat at night, and have diabetes (p < .05). Results were substantially consistent with those of prior research.

Adult↗

PubMed1993

Emotion and eating in obesity? A critical analysis.

Psychosomatic theories hold that the obese abnormally increase eating in response to emotional distress. Empirical support for this assertion has come mainly from self-report studies. A review of the literature for methodological rigor reveals that many studies previously considered supportive are substantially flawed with regard to control groups, failure to control Type-I error rate, and the possibility of confounding of social desirability and other response sets with self-reports of emotional eating. Five alternative conceptualization of the obesity-emotional eating association are presented along with suggested research which would elucidate the nature of this frequently reported connection.

Emotions↗

PubMed1993

Evidence of commingling in human eating behavior.

This investigation tested whether distributions of certain aspects of eating behavior were consistent with the notion of a "mixture model;" that is, two or more distinct commingled component distributions, consistent with the possibility of major gene action. Undergraduates (n=901) completed self-report trait measures of hunger, disinhibition, and dietary restraint. Variables were residualized for gender and age and transformed to remove skewness. Residualized transformed distributions were tested for departure from unimodality with Hartigan's dip statistic. The distributions of all three aspects of eating behavior were significantly non-unimodal. Next, component multivariate normal distributions were estimated via maximum likelihood. Likelihood ratio tests were employed to compare nested models. A mixture of four distributions with unequal variance-covariance matrices fit significantly better than any more parsimonious model. In sum, these data strongly suggest that the distributions of several measures of eating behavior are composed of four component distributions. This finding is consistent with the possibility of major gene effects for eating behavior.

Adolescent↗

PubMed1993

Can ethnic differences in men's preferences for women's body shapes contribute to ethnic differences in female adiposity?

In the United States, obesity is more common among black and Hispanic than white women. One putative cause of this difference is different cultural norms for attractiveness. Two studies assessed ethnic differences in men's perceptions of the attractiveness of females of varying sizes. In the first, 108 men recruited on the New York subway were shown sets of silhouettes depicting female bodies varying in fatness and were asked to pick the silhouette they found most attractive. They were also asked to indicate the thinnest and fattest figures they would consider dating. A measure of "latitude of acceptance" was computed as the difference between the thinnest and fattest figures considered. Results indicated no relationship between ethnicity and preference (F = 1.383, p = .257) or "latitude" (F = .102, p = .903). In Study 2, "personal advertisements" placed by 373 black, 1915 white, 110 Hispanic, and 30 Asian men from 35 newspapers and magazines were coded as: 1) thinness preferred; 2) no information on weight preference; 3) fatness preferred; or 4) states weight or looks unimportant. Results indicated a statistically significant but small association between ethnicity and preference (chi2 = 49.55, df = 9, p < .00001). Relative to white and Asian men, black and Hispanic men more frequently requested fat women, Hispanic men less frequently requested thin women, and black men more frequently stated that looks or weight did not matter. Ethnicity explained only 2.1% of the variance in preference. Thus, it seems unlikely that ethnic differences in men's preferences for women's body shapes contribute substantially to ethnic differences in female adiposity.

Adipose Tissue↗

PubMed1993

Resting energy expenditure in the obese: a cross-validation and comparison of prediction equations.

OBJECTIVE: To examine the accuracy and precision of 12 equations or tables for predicting resting metabolic rate (RMR) in obese persons. DESIGN: Observational (correlational) study. SETTING: Obesity Research Center, St Luke's/Roosevelt Hospital, New York, NY. SUBJECTS/SAMPLES: One hundred twenty-six (73 women, 53 men) healthy, obese subjects recruited through the Obesity Research Center's Weight Control Unit. MEASURES: RMR by indirect calorimetry. Weight and height were measured to the nearest 0.1 kg and to the nearest 1 cm. STATISTICAL ANALYSES PERFORMED: Bivariate regression of predicted RMR on measured RMR; paired t tests for the difference between means of predicted RMR and measured RMR. RESULTS: Of the 12 prediction equations, 6 had intercepts or slopes that were significantly different from 0 and 1, respectively. With two exceptions, the equations accounted for between 56% and 63% of the variance in measured RMR. The Robertson and Reid (1952) equation and the Fleisch (1951) equation performed best with our obese sample. APPLICATIONS/CONCLUSIONS: The Robertson and Reid (1952) and the Fleisch (1951) equations are recommended for clinical use with obese patients.

Adult↗

PubMed1993

Calculating effect sizes for meta-analysis: the case of the single case.

This paper reviews methods for deriving measures of effect for interrupted time-series (single case) designs. Limitations of prior models are described. Modifications of a regression approach developed by Center, Skiba, and Casey (1985-86, Journal of Special Education, 19, 387-400) which can simultaneously account for treatment effects on level and slope while controlling for effects of trend are advocated and a step-by-step computational algorithm is provided. The primary modification entails computing the initial estimate of trend only on baseline data. Implementation of the method with various forms of single case designs is described.

Algorithms↗

PubMed1993

Treatment of non specific dyssomnia with simple stimulus control procedures in a child with Down's syndrome.

Nonaversive behavioural interventions were used successfully to treat a disrupted sleep pattern in a child with Down's syndrome. A quasi-experimental single-case design was employed to evaluate the treatment efficacy. During the first phase of treatment, the mother implemented a structured bedtime routine and the child was no longer allowed to engage in activities while in bed. During the second phase, a stimulus control paradigm was employed in which a nearly life-sized rag doll was substituted for the mother in bed. Finally, the mother gradually withdrew from the child's bed and room. During baseline, the child spent an average of only six percent of the night sleeping alone. By the second phase, this rose to a mean of 26%. By the end of treatment this was increased to a mean of 78.2%. The increase was accompanied by collateral decreases in crying and distress. Improvements were maintained at follow-up.

Arousal↗

PubMed1992

Adiposity in children: is mental retardation a critical variable?

Several authors have suggested that obesity is more prevalent amongst children with mental retardation than non-mentally retarded children. However, studies on which this suggestion is based typically lack adequate control groups. The current research compared adiposity amongst mentally retarded versus non-mentally retarded children. Study 1 compared 110 mentally retarded children with 107 non-mentally retarded children (162 males, 61 females; age range 11 months-20 years). The independent (predictor) variables included IQ and mental retardation. Dependent (criteria) variables were BMI and age-corrected BMI. Study 2, using the National Health and Nutrition Examination Survey-II data bank compared 20 children with reported mental retardation with 4015 control children on three variables: BMI, age-corrected BMI, and subscapular to triceps skinfold ratio. Results of both studies found no significant difference in adiposity or body fat distribution between mentally retarded and non-mentally retarded children. Moreover, no significant difference emerged when either age or gender were controlled and no curvilinear or interaction effects were observed.

Adipose Tissue↗

PubMed1992

A combined behavioral/pharmacological treatment of sleep-wake schedule disorder in Angelman syndrome.

Angelman syndrome (AS) is a genetic disorder associated with a deletion on chromosome 15. Behavior problems among children with AS include sleep difficulties. Data are presented on the successful treatment of a sleep-wake schedule disorder (SWSD) in a 9-year-old boy with AS. The treatment program included behavioral and pharmacological components. During baseline, the child slept a mean of 1.9 hours per night and 1.3 hours during the day; night sleep was increased to a mean of 8.3 hours and day sleep was reduced to a mean of .08 hours after introduction of the full-treatment program. Medication was discontinued subsequently, and the child slept a mean of 7.8 hours during the night and .07 hours during the day. At 45-day follow-up, night sleep was maintained at 7.1 hours and day sleep remained stable at .29 hours. This is the first known report of an effective treatment of a SWSD in a child with AS.

Behavior Therapy↗