Genetic and environmental influences on systolic (SBP), diastolic (DBP), and mean arterial (MBP) blood pressure were examined using an expanded version of a path model in which parents and their singleton, twin, and adopted offspring were incorporated, and which also included an environmental index as an estimate of the underlying familial environmental component. Estimates of genetic heritability are lower in parents (10-15%) than in offspring (40-50%). Cultural heritability was significant for SBP (0.31) and MBP (0.40), and an intergenerational effect was found for DBP, with higher estimates in parents (0.42) than in offspring (0.21). Marital resemblance was significant, and no support was found for differential maternal and paternal cultural transmission. Two novel results arising from this study are 1) gender-specific sibling effects, with greater female than male resemblance for SBP and MBP and the opposite pattern for DBP, and 2) the suggestion of extra twin resemblance arising on account of additional shared environments and resulting in greater like-sex than opposite-sex twin resemblance. The major conclusions drawn from this study are that 1) parameter estimates are stable with or without the use of extensive environmental indices, and 2) the addition of twins and adoptees did not significantly impact the results, with the exception of a possible influence of the adoptees in estimates of cultural heritability for DBP. Combining both these features (i.e., extended relatives and environmental indices) enables testing for additional sources of familial aggregation, which is not possible using the traditional nuclear family approach and results in a more accurate assessment of the relative roles of heredity and environment on blood pressure than has been previously possible.

Adolescent↗

PubMed1989

Multivariate path analysis of specific cognitive abilities in the Colorado Adoption Project: conditional path model of assortative mating.

A multivariate path model of genetic and environmental transmission employing a conditional path representation of assortative mating was fitted to specific cognitive abilities data from the Colorado Adoption Project and evaluated using a maximum-likelihood estimation procedure. In agreement with results obtained from a previous analysis of a smaller data set, significant genetic covariation among the cognitive variables was indicated and evidence for a general genetic factor was found. However, cultural transmission parameters are nonsignificant and environmental correlations among the measures are relatively small.

Adoption↗

PubMed1989

The use, cost, and economic burden of nursing-home care in 1985.

Nursing-home expenses constitute one of the greatest financial risks for elderly Americans. This study, based largely on the 1985 National Nursing-Home Survey, examines the economic burden posed by nursing-home care during 1985. The results indicate that nursing-home expenses constitute by far the largest out-of-pocket burden of all health care services. It was found that nursing-home care expenses constituted 82.5% of the out-of-pocket expenditures among the elderly who incurred $3,000 or more in such expenditures during 1985. Surprisingly, though, it was found that the frequency in which those in nursing homes "spend-down" their assets and income, thus becoming eligible for Medicaid, is much lower than others have calculated. This may be due in part to the fact that a large proportion of the elderly are already eligible for Medicaid when they begin their nursing-home stays.

Aged↗

PubMed1989

Heterogeneity in the biological and cultural determinants of high-density lipoprotein cholesterol in five North American populations: the Lipid Research Clinics Family Study.

Heterogeneity in the source of familial resemblance for high-density lipoprotein (HDL) cholesterol in 5 different Lipid Research Clinics (Cincinnati, Iowa, Minnesota, Oklahoma and Stanford) was assessed using a general linear model for cultural and biological inheritance. No evidence of heterogeneity was found in any of the parameters of the model. Under the most parsimonious hypothesis, using data pooled over all clinics, genetic and cultural heritability were both significant and were estimated to be 0.52 +/- 0.04 and 0.09 +/- 0.02, respectively; there was cultural transmission but no maternal effects; marital and nontransmitted sibship environmental resemblance were significant.

Cholesterol, HDL↗

PubMed1989

PPOs: the employer perspective.

This paper reports the results of a national survey on employer experiences with preferred provider organizations (PPOs). The survey, conducted in 1987, included information from almost 700 telephone interviews with employee benefit managers. We found that 11 percent of employees are in PPOs. PPOs now have a strong presence among employers of all sizes. However, whereas they are a major force in the West, where almost one-third of employees are members, they have garnered only a 1 percent market share in the East. We examine the impact of PPOs on health insurance premiums and on employer satisfaction. The results show that in 1987, the year of the survey, PPOs appeared to provide mild cost savings compared to conventional insurance, and that employers were very satisfied with almost all aspects of PPOs, whereas they were surprisingly critical of their HMOs.

Consumer Behavior↗

PubMed1989

Paying physicians in Canada: minding our Ps and Qs.

Explore the source record for details and available documents.

Canada↗

PubMed1989

Trading off access to enhance welfare.

Explore the source record for details and available documents.

Aged↗

PubMed1989

Cardiovascular risk factors in a French-Canadian population: resolution of genetic and familial environmental effects on blood pressure by using extensive information on environmental correlates.

Genetic and environmental influences on systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial blood pressure (MBP) were examined in 371 French-Canadian families by using path analysis. Familial environment was estimated with environmental indices constructed from as many as 14 (of a pool of more than 100) correlates of blood pressure (BP). Approximately 20% of the variance in BP can be accounted for by the composite index, and the types of variables and the direction of their effects vary as a function of age and of the multivariate context. Path analysis of the family data suggests that genetic heritability is relatively high in children (from 0.49 for SBP to 0.56 for MBP) but much smaller in adults (from 0.08 for DBP to 0.18 for SBP). The proportion of variability explained by familial environment is estimated to be the same in children and adults and is much higher than reported to date (from 0.30 for SBP to 0.42 for DBP). In addition, sibships share significant nontransmitted environmental effects, and there is no evidence to suggest specific maternal effects in the aggregation of BP. Two unique findings emerge from this study. First, unlike in most earlier studies, we were able to arrive at the same parsimonious model for each of the BP variables. Second, the familial environment accounts for a substantial proportion of the variability in BP, which has been considerably underestimated in earlier studies.

Blood Pressure↗

PubMed1988