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T Rice

Publications and source records attributed to T Rice.

At least 145 records · Page 8Linked to original sources
PubMed1991

Commingling analysis of generalized body mass and composition measures: the Québec Family Study.

Human body mass and composition are heterogeneous phenotypes resulting from the combined effects of genes, environmental factors, and their interactions. In order to gain an understanding of the individual genetic determinants leading to obesity, we have initiated a systematic analysis of several measures of fatness and its phenotypes including: the body mass index (wt/ht2), fat mass, fat-free (lean) mass, the ratio of fat mass over fat-free mass, percent body fat, and a fat mass index (fat mass/ht). In this report, we examine the distributions of these age and sex adjusted variables in a large family study from Québec in terms of evidence for commingling and skewness, and evaluate the inter-relationships among the measures. Fat mass, fat-free mass and the fat mass index conceptually represent primary variables in that they are quantitative measures of relevant components of total body weight; the hypothesis of a single distribution was inferred for each of these primary measures, with significant residual skewness except for fat mass. In general, offspring (8-26 years old) distributions were more positively skewed than parent (30-60 years old) distributions. The remaining variables (body mass index, fat mass to fat-free mass ratio, and percent body fat) are indexes combining information on fat and fat-free mass into single measures. Although offspring data were consistent with a single skewed distribution, commingling was found in the parents in each case. The prominent heterogeneity between generations suggests that there may be significant developmental (genetic or environmental) effects in the transition during growing years to adult pattern phenotypes, particularly for the complex indicators of body composition.

Adipose Tissue↗
PubMed1991

Private health insurance and medical care utilization: evidence from the Medicare population.

This paper examines the impact of supplemental health insurance policy ownership on the use of health care services by the elderly. It employs a data base consisting of Medicare claims data from over 2,000 beneficiaries in six states, actual copies of their supplemental insurance policies, and detailed survey information. The results show that policy ownership has a substantial, positive impact on service usage and costs, particularly for beneficiaries in fair or poor health. The greatest impact was found for policies that provide first-dollar coverage.

Aged↗
PubMed1991

Familial aggregation of lipids and lipoproteins in families ascertained through random and nonrandom probands in the Minnesota Lipid Research Clinic Family Study.

The familial aggregation of lipids [total cholesterol (CH) and triglyceride (TG)] and lipoproteins [high-density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL)] was investigated in families ascertained through both random and nonrandom probands in the Minnesota Lipid Research Clinic Family Study. Nonrandom proband ascertainment was based on single selection through truncation for hyperlipidemia at an earlier screening. A path model was used to investigate the nature of familial resemblance using appropriate adjustments for ascertainment and to determine whether random and hyperlipidemic samples are heterogeneous with regard to the multifactorial model. The results suggest that parameter estimates are consistent with those from previous studies in which only random families were used and that random and nonrandom samples are homogeneous with regard to the path model for CH and LDL. However, for TG and HDL the random and hyperlipidemic samples are significantly heterogeneous. This heterogeneity would be observed if familial hypertriglyceridemia and/or familial hypoalphalipoproteinemia segregates predominantly in the hyperlipidemic rather than in the random sample, as on might expect.

Chromosome Banding↗
PubMed1991

The effect of owning private long-term care insurance policies on out-of-pocket costs.

This article examines the effect of owning long-term care insurance policies on the amount of out-of-pocket costs incurred by the elderly during their nursing home stays, and the importance of different policy features and restrictions. Data were drawn from the 1985 National Nursing Home Survey, and from copies of long-term care insurance policies collected from 11 leading companies during the spring and summer of 1988. The study results show a great deal of uncertainty concerning amounts the policies are likely to pay toward nursing home stays. This implies that the policies collected did not adequately fulfill one of the primary purposes of insurance: a reduction in risk and uncertainty. To examine whether rapid policy changes in recent years have made a difference, we assessed each of seven policy features and found that the two most important restrictions in long-term care insurance policies are prior hospitalization and level-of-care requirements. Recently, the National Association of Insurance Commissioners (NAIC) recommended that states prohibit the sale of policies containing these restrictions. Our findings confirm the wisdom of this recommendation. We did find, however, that two other policy restrictions--policy maximums and lack of inflation adjustment--are problematic. We recommend that the NAIC expand its model regulations to require that policy maximums be a minimum of four years, and that some form of inflation protection be incorporated into policy benefit structures.

Aged↗
PubMed1991

The effectiveness of consumer choice in the Medicare supplemental health insurance market.

This article examines the factors that affect Medicare beneficiaries' choices in the supplemental health insurance market. Data include detailed survey information as well as copies of the health insurance policies owned by a sample of approximately 2,500 Medicare beneficiaries in six states during 1982. Logit analysis is employed to analyze the determinants of four dependent variables: whether a person owns (1) one or more private supplemental insurance policies, (2) two or more policies, (3) at least one policy that we define as "effective," and (4) a policy we define to be "less effective." Those who are better off from a socioeconomic standpoint appear to be making more effective choices in the supplemental health insurance market. However, there does not appear to be a relationship between consumer ignorance or vulnerability and the purchase of multiple supplemental insurance policies. Study results imply an important role for public policy in helping to provide the information necessary to ensure that the most vulnerable beneficiaries make insurance choices that are in their best interest.

Aged↗
PubMed1990

Heterogeneity in the familial aggregation of fasting serum uric acid level in five North American populations: the Lipid Research Clinics Family Study.

This study represents the first formal examination for heterogeneity in the familial aggregation of fasting serum uric acid (UA) levels. Data from 5 clinics (Cincinnati, Stanford, Iowa, Minnesota, and Oklahoma) participating in the Lipid Research Clinics (LRC) family study, which included a total of 685 nuclear families (N = 2,146), were analyzed. Heterogeneity among the clinics in familial resemblance was detected. However, this heterogeneity could not be attributed to differences in distributional properties (such as means and variances) or to path model parameters representing latent genetic or cultural (environmental) components associated with UA levels. Intergenerational differences in genetic heritabilities were found, with higher offspring (h2 = 43%) than parent (h2z2 = 16%) estimates, but no generational differences were detected for cultural heritability (c2 = 0.09). Equal maternal and paternal cultural transmission was found, and effects due to extra sibling environments and to marital resemblance were both significant. These results show no clear indication as to the source of the heterogeneity observed for familial resemblance of UA levels in randomly selected data. This question should be further investigated, especially in clinical samples such as dyslipoproteinemic families.

Adult↗
PubMed1990

Continuity and change in preferred provider organizations.

This paper presents the results from a national survey of preferred provider organizations (PPOs) that was conducted in 1988. It is based on telephone interviews conducted by the authors with executives in over 170 PPOs in the United States. We compare the survey results with those obtained from similar surveys conducted in 1985 and 1986, allowing us to assess the extent to which PPOs have grown and changed. We found that PPOs have continued to grow at an extremely rapid rate. During the Summer and Fall of 1988, the time in which the survey took place, 37.6 million people were eligible to use PPO benefits, compared to the 16.5 million figure we obtained two years earlier. We did not find, however, that PPOs are moving in the direction of providing more innovative forms of health care cost containment. Most PPOs still rely on discounts from providers and utilization review to achieve savings. There is little trend towards using incentive reimbursement techniques and choosing preferred providers that have shown themselves to be cost-efficient. We conclude that in the coming years PPOs must demonstrate the ability to control rising health care costs. To accomplish this, they will need to put more pressure on providers to use resources more sparingly. Otherwise, they may lose their market share to other forms of managed care.

Capitation Fee↗
PubMed1990

Heterogeneity in the familial aggregation of fasting plasma glucose in five North American populations: the Lipid Research Clinics Family Study.

Heterogeneity in the familial aggregation of plasma glucose in five samples of the Lipid Research Clinics Family Study (LRC) was investigated using path analysis. This study was deemed appropriate since recent investigations reported a wide range of estimates for genetic and cultural factors. The path model incorporated a measured index of the familial environment in order to separate the effects of genes and environments in the nuclear family design, genetic and environmental heritabilities, spouse resemblance, sibling environmental effects, and parental cultural transmission. The methodology was completely general in allowing sample-specific, as well as pooled-sample, estimation of all or any subset of the model parameters. Genetic heritability estimates were heterogeneous, ranging from zero to 33% across the clinics. Environmental heritability (7%), spouse resemblance, non-transmitted sibling environmental effects, and parental cultural transmission were homogeneous across samples. No support was found for specific maternal effects, nor for intergenerational differences in cultural or genetic heritability. We conclude that the genetic and environmental heritabilities for plasma glucose in the LRC are consistent with the diverse reports by earlier investigators. In addition, we were able to exclude methodological differences as a cause of this heterogeneity. Furthermore, formal hypothesis tests suggest that the aetiology of this heterogeneity is genetic (and not cultural), taking the form of two distinct homogeneous patterns (one for no genetic effect, and one for a moderate genetic effect). Only formal heterogeneity tests of the type described here can detect these effects, and allow pooling of separate studies in order to obtain more precise estimates of the parameters of interest.

Adult↗
PubMed1990

A genetic study of immunoglobulin E and atopic disease based on families ascertained through asthmatic children.

In order to investigate the modes of inheritance of serum immunoglobulin E (IgE) levels and atopic disease, serum IgE levels and data on allergic disease were obtained from 42 families ascertained through asthmatic children visiting an allergy clinic. Although the mean IgE levels were elevated (mean 637 U/ml), the prevalence of atopic disease in this population was surprisingly low. When the data were analyzed using complex segregation analysis, no major locus could be detected. Moreover, the polygenic heritability was unexpectedly small even though the correlation between serum IgE levels and the liability to atopic disease was around 0.4. Given this unusual set of findings, it is postulated that parasitic infections in this population have (in accordance with well-established results of parasitic disease) caused both elevated levels of serum IgE and a decreased prevalence of allergic disease with the possible masking of the various genetic components of serum IgE levels and atopic disease.

Asthma↗
PubMed1990

Volume performance standards: can they control growth in Medicare services?

Congress has adopted volume performance standards (VPSs), a system using collective incentives, as a means to control costs of physicians' services under the Medicare program. Past efforts to curb expenditures failed to focus sufficiently on providing direct incentives to individual providers or consumers, and did not achieve desirable results. West German and Canadian experiences suggest that mechanisms to contain costs may work best when their scope is regional rather than national, prompting the view that the VPS system should operate on a state level. The system's efficacy may also require Medicare officials to analyze utilization patterns assiduously, and states' medical and professional organizations to monitor physicians' practices and formulate due practice guidelines.

Cost Control↗
PubMed1990

Commingling and segregation analysis of blood pressure in a French-Canadian population.

Commingling and segregation of age-sex-adjusted systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial blood pressure (MBP) were examined in 1,560 individuals from 374 French-Canadian nuclear families. After correction for skewness, evidence in favor of two commingled distributions was found for SBP in the combined data (parents and offspring) and in parents, but not in offspring. Segregation analysis (using the computer program POINTER) suggested that a multifactorial contribution to all three phenotypes was greater in offspring than in parents, which could be the result of either polygenic or shared environmental components relevant to sibships, or both. Statistical evidence was found for a major effect on SBP. However, Mendelian transmission of the major effect was rejected, and no transmission of the major effect (equal tau's) was not. This is just the opposite to what would be expected if the major effect was due to a major gene, and it would ordinarily be considered as sufficient evidence to refute a major gene effect on SBP. However, the commingling in parents but not in offspring (who are all below 26 years of age), and the finding of equal transmission probabilities (nearly equal to 1), are compatible with an alternative interpretation. It is possible that there is a real major gene effect on SBP but that the genotype for elevated SBP has not yet expressed itself in the offspring as they have not yet gone through the risk period. Accordingly, this possibility needs to be evaluated further in additional studies involving older offspring.

Blood Pressure↗