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Biomedical subjects

S Heshka

Publications and source records attributed to S Heshka.

At least 37 records · Page 2Linked to original sources
PubMed1995

Systematic organization of body-composition methodology: an overview with emphasis on component-based methods.

The field of body-composition research currently lacks a systematic organization of methods used to quantitate components at the atomic, molecular, cellular, tissue-system, and whole-body levels of body composition. In this report we propose a classification system for body-composition methodology that proceeds in steps, beginning with division of methods into in vitro and in vivo categories, advances to organization by measurable quantity (property, component, or combined), and ends with grouping of methods by mathematical function (types I and II). Important characteristics of component-based methods are then developed, including a classification of component relationship types, the role of ratios and proportions in type II component-based methods, and the basis of simultaneous equations in multicomponent methods. This classification system, the first founded on a conceptual basis, explains similarities and differences between the many diverse methods, provides a framework for teaching body-composition methodology theories to students, and suggests future research opportunities.

Body Composition↗
PubMed1995

A randomised placebo-controlled clinical trial of an acupressure device for weight loss.

OBJECTIVE: To provide a randomized placebo-controlled trial to determine the efficacy of an auricular acupressure device. DESIGN: Subjects were randomly assigned to either treatment or placebo. The treatment group received the acupressure device and were instructed to use the device in their dominant ear. The placebo group received an acupressure device for their wrist. Participants were followed for 12 weeks. SETTING: Outpatient core of the New York Obesity Research Center. SUBJECTS: 96 obese adult volunteers, 80 females and 16 males, between 19 and 70 years of age. MEASUREMENTS: Weight, body fat, and blood pressure measured every two weeks. RESULTS: All subjects combined lost, on average, 0.96 kg. There was no significant difference between the two groups on weight loss (mean wt loss = 1.28 [s.d. = 2.74] kg for treatment and 0.63 [s.d. = 3.26] kg for placebo) regardless of whether all subjects were examined or only the most compliant subjects were examined. Similarly, there were no significant differences between the two groups regarding fat loss or blood pressure reduction. CONCLUSION: The acupressure device appears to be a safe device (did not cause any harmful side effects). However, it did not promote significantly greater weight or fat loss, or declines in blood pressure than placebo.

Acupressure↗
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

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

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↗
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

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↗
PubMed1992

Discrepancy between self-reported and actual caloric intake and exercise in obese subjects.

BACKGROUND AND METHODS: Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet--low total energy expenditure and underreporting of caloric intake--in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance. RESULTS: Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic effects of food and exercise. Low energy expenditure was thus excluded as a mechanism of self-reported diet resistance. In contrast, the subjects in group 1 underreported their actual food intake by an average (+/- SD) of 47 +/- 16 percent and overreported their physical activity by 51 +/- 75 percent. Although the subjects in group 1 had no distinct psychopathologic characteristics, they perceived a genetic cause for their obesity, used thyroid medication at a high frequency, and described their eating behavior as relatively normal (all P < 0.05 as compared with group 2). CONCLUSIONS: The failure of some obese subjects to lose weight while eating a diet they report as low in calories is due to an energy intake substantially higher than reported and an overestimation of physical activity, not to an abnormality in thermogenesis.

Calorimetry↗
PubMed1992

Combination therapy for NIDDM with biosynthetic human insulin and glyburide.

OBJECTIVE: TO investigate the effects of the addition of glyburide to the regimen of insulin-treated non-insulin-dependent diabetes mellitus (NIDDM) patients with regard to their overall insulin requirement and dosage schedule and to assess persistence of these effects. RESEARCH DESIGN AND METHODS: A double-blind randomized parallel-groupo, placebo-controlled, 20-wk outpatient trial at the Clinical Research Unit (CRU) at St. Luke's/Roosevelt Hospital (New York). Subjects were 20 insulin-dependent NIDDM patients previously managed on insulin alone. After a baseline period of satisfactory diabetes control on biosynthetic human insulin alone, insulin dosage was halved, and patients were placed on a combination with either glyburide or placebo. Diabetes control equivalent to baseline was reestablished by adjusting insulin as required on subsequent visits to the CRU. RESULTS: Insulin requirements in the glyburide group decreased by 29 U at 14 wk compared with 9 U in the placebo group (P less than 0.05). At 20 wk, the decreases remained significant (25 vs. 11 U, respectively; P less than 0.05). The mean +/- SD reduction in insulin requirement in the glyburide group was relatively constant (25 +/- 10 U) and was not related to premedication insulin requirement. Successful response to glyburide was inversely correlated with initial serum alkaline phosphatase level. CONCLUSIONS: Glyburide reduces insulin requirements for 20 wk of combination therapy in NIDDM patients. Patients whose initial insulin requirement is less than or equal to 25 U have a 50% chance of achieving equivalent glycemic control on glyburide alone.

Aged↗
PubMed1991

Toward an empirically derived typology of obese persons.

The MMPI, medical, anthropomorphic, and laboratory evaluations were completed by 260 obese patients (211 females, 49 males) at a New York hospital. Biological and psychological variables were separately subjected to principal components analyses. Fifteen biological and five psychological components were extracted. A three-cluster solution was selected from a K-means clustering on biological components, replicated via Ward's method, and validated via a discriminant analysis on psychological components. Cluster 1, 'android obesity', contained 75 percent of the males and was characterized by 'masculine phenotypy', 'poor conditioning' and 'adverse serum lipids', and less 'feminine' responding on the MMPI. Cluster 2, 'gynoid obesity', was low on components measuring physical stress and masculine phenotypy, was 95 percent female, moderately obese compared to clusters 1 and 3, and had a relatively healthy profile. Cluster 3 had elevations on overall fatness and physiological and psychological stress, and low scores on a 'healthy blood synthesis' component. This cluster, labeled 'morbidly obese', was the most obese and had profiles suggesting adverse effects of obesity.

Adult↗
PubMed1990

Weight loss and change in resting metabolic rate.

The relation between change in resting metabolic rate (RMR) and change in fat-free mass (FFM) after weight loss is not well understood and is often inappropriately expressed in kilocalories per unit of FFM. We measured RMR and FFM in 35 obese patients enrolled in a conservative weight-loss program. RMR per kilogram FFM was not different after weight loss. However, the regression of delta RMR on delta FFM revealed that the decline in RMR tended to be greater than could be accounted for by loss of FFM. At initial test and retest, body fat (Fat) was not a predictor of RMR after FFM had been taken into account but delta Fat significantly contributed to the prediction of delta RMR when added to the equation after delta FFM. Thus, people losing larger amounts of weight had declines in RMR greater than could be accounted for by loss of FFM. Self-reported age of onset of obesity was not related to delta RMR.

Adipose Tissue↗
PubMed1990

Childhood onset (age less than 10) obesity has high familial risk.

We assessed risk for obesity in 1743 first-degree relatives (parents and siblings) of 566 obese patients at three sites in the USA and one in Argentina. Onset of obesity prior to adulthood, and especially by age 10, significantly increased relative risk (2.14) for obesity in adult first-degree relatives. This increase in risk was consistent across four different patient samples from two different countries. Higher levels of obesity in patients were also associated with increased familial risk. Age of onset of obesity may be used to select obese adults with high genetic loading--an approach that should facilitate the identification of specific genes for human obesity. The enhanced ability to identify persons at high genetic risk for obesity provided by this study should increase the effectiveness of efforts to prevent obesity.

Adolescent↗