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T Rice

Publications and source records attributed to T Rice.

At least 109 records · Page 6Linked to original sources
PubMed1994

An exploratory investigation of genetic linkage with body composition and fatness phenotypes: the Québec Family Study.

In the present investigation, we have attempted to identify regions of the genome in which "obesity genes" potentially reside using robust sib-pair linkage analysis. Data were collected on 1,628 individuals in 301 nuclear families residing in the environs of Québec City during the period 1978-1981. In addition to traditional blood group antigens and enzyme polymorphisms, several phenotypes in the obesity domain that are associated with increased morbidity were assessed, including measures relating to heaviness (i.e., the body mass index), body composition and nutrient partitioning (i.e., % body fat), and regional fat distribution without and with standardization for total fat mass (i.e., the sum of six skinfold thicknesses, and the ratio of the sums of trunk to extremity skinfold thicknesses). Three consistent patterns of potential linkage relationships with obesity phenotypes were revealed in these data, involving the marker loci adenosine deaminase, the Kell blood group antigen, and esterase D, which identify chromosomal regions 20q13, 7q33, and 13q14, respectively. Other potential linkages also were identified in the short arm of chromosome 1, interesting because of the presence of the db and fa loci on homologous regions of chromosome 1 in mouse and rat models of obesity, respectively. Each of the tentative linkage relationships reported here warrant follow-up using alternative methods and require replication in independent studies.

Adenosine Deaminase↗
PubMed1994

A re-examination of the meaning and importance of supplier-induced demand.

Despite twenty years of work on supplier-induced demand (SID) there has been little discussion or investigation of how inducement affects the health of patients. We develop a conceptual framework for SID which includes the clinical effectiveness of the health services utilized as well as the effectiveness of the agency relationship between the physician and the patient. The framework is used to identify several conceptually distinct types of utilization--each with its own policy implications--which have been intermingled in the SID literature. After examining each type of utilization, we conclude that a continued focus by health economists on the phenomenon of inducement (even within an extended conceptual framework) may be too limited for the development of policies regarding health service utilization.

Decision Making, Organizational↗
PubMed1994

Evidence for an association between dehydroepiandrosterone sulfate and nonfatal, premature myocardial infarction in males.

BACKGROUND: Several studies indicate that endogenous hormones play a role in the etiology of coronary artery disease, either as independent risk factors or indirectly, via an effect on lipids, lipoproteins, or other heart disease risk factors. METHODS AND RESULTS: The relation between endogenous hormone levels and premature (< 56-year-old patients) myocardial infarction was assessed in a retrospective study involving 49 male survivors of premature myocardial infarction and 49 age-matched, volunteer male controls. Serum samples were obtained for each subject the morning after a > or = 12-hour fast and frozen at -70 degrees C for subsequent hormonal analysis. Among the male patients, the average duration between the most recent myocardial infarction and blood sampling was 3.4 years (range, 0.7 to 19.2 years). Individuals reporting the use of any medications with the potential to alter lipid, lipoprotein, or hormone levels were excluded from these analyses. Dehydroepiandrosterone sulfate levels were significantly lower in the patients than in the control subjects. This association remained statistically significant even after accounting for the effects of total cholesterol, triglycerides, the ratio of total to high-density lipoprotein (HDL) cholesterol, HDL, apolipoprotein A-I, apolipoprotein A-II, apolipoprotein B, and body mass index. There were no significant differences in the levels of estradiol, testosterone, or free testosterone or the ratio of estradiol to testosterone between patients and control subjects. CONCLUSIONS: Our conclusions are limited by the retrospective nature of this study. However, these data indicate that serum dehydroepiandrosterone sulfate levels are inversely related to premature myocardial infarction in males and that this association is independent of the effects of several known risk factors for premature myocardial infarction.

Age Factors↗
PubMed1994

Should insurers pay the same fees under an all-payer system?

Medicare's use of diagnosis-related groups (DRGs) and the resource-based relative value scale (RBRVS) has led to interest in developing a national all-payer system in which insurers use the same payment methods and payment rates. Using data for 81 high-volume DRGs from 457 California hospitals, we conclude that a single set of rates for hospital care would not be appropriate. On average, Medicare patients were 11.7 percent more expensive than commercially insured patients, but less expensive in many DRGs. Further research is needed to determine if Medicare patients require more physician resources compared with non-Medicare patients, particularly for surgical procedures.

California↗
PubMed1994

Cross-trait familial resemblance for body fat and blood pressure: familial correlations in the Québec Family Study.

Cross-trait resemblance between body fat and blood pressure (BP) was examined among families in the Québec Family Study by using a bivariate familial correlation model assessing both intraindividual (e.g., comparison of father's body fat with his own BP) and interindividual (e.g., comparison of father's body fat with son's BP) cross-trait correlations. Each of six body-fat measures-(i) percent body fat, (ii) body-mass index, (iii) the sum of six skinfolds, (iv) the ratio of the sum of six skinfolds to total fat mass, (v) the ratio of the trunk skinfold sum to the extremity skinfold sum, and (vi) the regression of the trunk-extremity skinfold ratio on the sum of six skinfolds--was analyzed separately with systolic BP and with diastolic BP. Results showed that (1) upper-body fat was the strongest interindividual correlate of BP (especially the correlation of trunk-extremity ratio with diastolic BP), suggesting shared pleiotropic genetic and/or common familial environmental effects; (2) summary body-fat measures either were inconsistent (in the case of both percent body fat and sum of six skinfolds) or gave no evidence of interindividual cross-trait resemblance with BP (in the case of body-mass index); and (3) intraindividual resemblance between the sum of six skinfolds and BP largely vanished once the skinfold sum was adjusted for fat mass, suggesting that the intraindividual association may be mediated largely by the absolute amount of subcutaneous fat rather than by the subcutaneous proportion. Finally, the magnitude of the spouse resemblance for the trunk-extremity ratio with diastolic BP suggests that a significant proportion of the resemblance may be due to environmental influences. In summary, our investigation confirms a heritable link between BP and truncal-abdominal fat as predicted by the metabolic-syndrome hypothesis. That this result is obtained in primarily normotensive, nonobese families, suggests the connection involves normal metabolic paths.

Adipose Tissue↗
PubMed1994

Commingling analysis of adiposity in an Indian population.

The distributions of five adiposity phenotypes were assessed for the presence of commingling in a sample of 756 adults (> or = 30 years old), residing in the Chittoor district of Andhra Pradesh, India. Three measures of generalized fatness (body mass index, the sum of six skinfolds and the sum of three trunk skinfolds) and two indicators of fat patterning (the ratio of trunk to extremity subcutaneous fat and the ratio of the subscapular skinfold to the sum of the subscapular and the supra-iliac skinfolds) were analysed. Each phenotype was adjusted for the effects of (i) age within sex, and (ii) age, energy intake and energy expenditure within sex. The distribution of each phenotype, under both adjustment schemes, was assessed for evidence of commingling. The commingling analyses were performed separately for males (n = 397) and females (n = 359), and evidence for heterogeneity in the distribution of each phenotype, by sex, was evaluated. There is evidence of commingling in the distribution of each phenotype, under both adjustment schemes. Conclusions regarding the distributions of these phenotypes are, however, influenced by the specific adjustments made to the data. In general, the measures of generalized fatness are more sensitive than measures of fat patterning to the specific adjustments applied to the data. Interestingly, and in contrast with the majority of commingling analyses of adiposity, the smallest components of the commingled distributions often have the lowest mean phenotypic value.

Adipose Tissue↗
PubMed1993

Cincinnati myocardial infarction and hormone family study: family resemblance for testosterone in random and MI families.

Familial correlations for total testosterone and free testosterone were examined in both random and nonrandom families participating in the Cincinnati Myocardial Infarction and Hormone Family Study (CIMIH). The non-random families were ascertained through Caucasian males who had survived a myocardial infarction (MI) prior to age 56 years, while random families were recruited largely through an adolescent boy maturation study. Eight sex-specific familial correlations were estimated (father-mother, father-son, father-daughter, mother-son, mother-daughter, son-son, daughter-daughter, and son-daughter) for each of the MI and random samples using maximum likelihood methods with appropriate ascertainment correction. These familial correlations were examined for differences between the random and MI samples, as well as for sex-specific familial patterns. The results suggest that total testosterone levels may have a limited role in determining MI risk, as evidenced by the overall heterogeneity between samples, and lower serum levels in MI than random probands. The pattern of correlations for both androgens suggests that a simple genetic model appears unlikely; however, familiarity cannot be ruled out. Although possible covariate effects such as age and sex may have masked some potentially significant results, especially in males, familiarity in females is suggested (correlations ranging from .3-.9). The relative stability of these hormones in females as compared to that in males may have contributed to its identification, and suggests the familial transmissibility may be associated with adrenal production and/or metabolic clearance of testosterone.

Adolescent↗
PubMed1993

Assessment of adiposity in an Indian population: familial correlations.

Familial correlations for five measures of adiposity were assessed using data from 473 nuclear families residing in the Chittoor district of Andhra Pradesh, India. Fat patterning, measured as the ratio of trunk to extremity subcutaneous fat, and the ratio of the subscapular to the sum of the subscapular and suprailiac skinfolds, and three measures of generalized fatness: body mass index, the sum of six skinfolds and the sum of three trunk skinfolds were analyzed. Maximum likelihood estimates of the familial correlations were obtained for each phenotype, after adjusting for the effects of (1) age within sex, and (2) current levels of energy intake and expenditure, and age within sex. Hypotheses regarding sex-specific, and generational differences in these correlations were assessed for each phenotype, under both adjustment schemes. The strength and pattern of the familial correlations for the three measures of generalized fatness were markedly influenced by the specific adjustments applied to the data. In contrast, the familial correlations for the fat patterning phenotypes were quite similar under the two adjustment schemes. Comparison of our results with previously published data indicates that the familial correlations for a subset of these adiposity measures may be heterogeneous across populations.

Adipose Tissue↗
PubMed1993

Segregation analysis of body mass index in an unselected French-Canadian sample: the Québec Family Study.

Interest in a single gene etiology for obesity, as assessed by the body mass index (BMI), has been spurred recently by reports of a putative recessive major gene for extreme values, which accounts for as much as 40% of the variance. The major gene hypothesis was evaluated here in the Québec Family Study, a random sample of 375 French-Canadian volunteer families. This report represents one component in a more complete investigation of obesity in these families. In contrast to the recent studies, a major gene hypothesis for BMI was not verified here. Although there was a major effect, it did not conform to a Mendelian pattern of transmission. A multifactorial component (i.e., polygenic and/or common environmental factors) accounted for 42% of the phenotypic variance. In addition, evidence of heterogeneity between the generations was found. The heterogeneity was traced to the major non-Mendelian component (which accounted for 0.01% of the variance in parents and over 40% in offspring) rather than to the multifactorial one. These results would suggest that a simple recessive gene mixed model may not be sufficient to explain the familial distribution of the BMI. Several factors which may have contributed to these results include temporal trends and surrogate effects such as those related to variation in body composition and energy balance components.

Adipose Tissue↗
PubMed1993

The Cincinnati Myocardial Infarction and Hormone Family Study: family resemblance for dehydroepiandrosterone sulfate in control and myocardial infarction families.

Dehydroepiandrosterone sulfate (DHEAS) was examined in random (control) and nonrandom (case) families participating in the Cincinnati Myocardial Infarction and Hormone (CIMIH) family study. The case families were ascertained through white men who survived a myocardial infarction (MI) before the age of 56, whereas control families were recruited through advertisements and through an adolescent boy maturation study. Both familial correlations and genetic effects of DHEAS were investigated. First, maximum likelihood estimates of the sex-specific familial correlations (corrected for nonrandom ascertainment) suggested that there was significant heterogeneity between the two sampling types. This heterogeneity was isolated to the male sibling correlation, which was higher in the case than control families. Post hoc analyses suggested that the sibling group heterogeneity may be in part a function of age, since the control sample offspring were on average much younger than those in case families. No sex differences other than those for the siblings were noted in the familial correlations. Second, heritability was investigated in control families using a simple path model (TAU) that allowed for sex differences. The only significant model parameter was the sex-specific familiarity (combined polygenic and familial environmental effects), which was larger in females (74%) than in males (29%). In general, these analyses suggested that (1) DHEAS may play only a limited role in the increased risk for premature MI, and (2) the degree of heritable (familial) variation may be dependent on sex.

Adolescent↗
PubMed1993

Income-related cost sharing in health insurance.

The vast majority of health plans in the United States require patients to meet cost-sharing requirements that are unrelated to income. Because this is highly inequitable, the authors propose a new system in which cost sharing is explicitly linked to income levels. This proposal differs from earlier proposals to relate cost sharing to income, which relied on the federal income tax system. In this plan, employers and insurers (both public and private) would collect the information necessary to relate cost sharing amounts to income. The proposal could be applied to nearly any health system reform proposal currently under discussion. The authors examine the experience of a number of U.S. firms that have already incorporated income-related cost sharing, as possible models to apply to health insurance nationwide.

Cost Sharing↗