[The relationship between salt consumption and blood pressure; physiological model as opposed to demographic reality].
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Female↗
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Results for “Demographic modelling”
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Micro-history and the macro-models of the European demographic system in pre-industrial times: life course patterns in the Parish of Belm (Northwest Germany), seventeenth to the nineteenth centuries.
"Current models of the European demo-economic system in pre-industrial times are based on strong assumptions about the predominant patterns of individual life courses. Now recent micro-studies of individual communities make it possible to check whether the actual patterns of life fit these assumptions. The findings for Belm present an amazing blend of confirmations and contradictions. In particular, the connection between marriage and the formation of a new self-supporting household is subject to doubt. Together with the findings of other micro-studies, the evidence for Belm suggests that the assumptions about mechanisms linking marriage to economic resources should be reconsidered, and that there is need for a dialogue between macro-theories and micro-history."
Developed Countries↗
Model life table fitting by maximum likelihood estimation: a procedure to reconstruct paleodemographic characteristics from skeletal age distributions.
A procedure is presented that uses the regression coefficients for the Coale and Demeny west model life tables to model selected demographic characteristics from skeletal age-at-death distributions. Model death distributions were constructed and compared to a given skeletal distribution, using methods of maximum likelihood estimation to determine the best fit. Two chi-square tests are employed to evaluate the degree of fit. The resulting model includes estimates of demographic characteristics including gross reproductive rate, crude birth rate and life expectancy. The procedure is applied to three archaeological skeletal samples as test cases: two from eastern North America and one from Mexico. These display a range of correspondence (between the best fitting model and the data) from good to poor. The proposed procedure is a potentially powerful tool for both reconstructing paleodemographic rates and illuminating differences between typical human patterns and those found in archaeological populations.
Actuarial Analysis↗
A macro demographic and socioeconomic development model.
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Birth Rate↗
Prediction of the rate of decline in cognitive function in Alzheimer's disease: a model based on simple demographic data and widely used rating scales.
Dementia represents a significant burden on the resources of both the National Health Service and Social Services as well as a great strain on the caregivers. The ability to predict, at diagnosis, those dementia patients that will deteriorate rapidly would allow a more effective allocation of resources as well as enabling the families and caregivers to make appropriate preparations. We performed discriminant analysis on a placebo data set of over 5,000 patients with Alzheimer's disease in order to create a model that predicts the rate of cognitive decline in Alzheimer's disease from simple demographic data and the baseline score on the cognitive subscale of the Alzheimer's Disease Assessment Scale or the Mini Mental State Examination. This model has 96-97% sensitivity and 92-93% specificity. The potential benefits of this model argue for its validation in a prospective study.
Adult↗
Comparison of risk adjusters for medicaid-enrolled children with and without chronic health conditions.
OBJECTIVE: Several capitation payment systems have been developed and implemented recently by public and private insurers as well as by individual managed care organizations. Many pediatricians have expressed concern that methods for establishing capitation rates may not adequately account for the higher expected expenditures for children with chronic health conditions. In this study, we evaluate a demographic- and 4 diagnosis-based models, paying particular attention to their performance for children with chronic health conditions. METHODS: We selected children 18 years of age and under who were enrolled in the Maryland Medicaid Program in 1995 and 1996. We defined the population of children with chronic health conditions using ICD-9 codes. Individual and group-level analyses were utilized to measure the ability of the different risk adjustment models to predict expenditures in 1996 based upon information available in 1995. RESULTS: All 4 diagnosis-based models significantly outperformed the demographic model for children overall and for children with chronic health conditions. Differences between diagnosis-based models were small, especially as the size of test populations increased. CONCLUSIONS: Risk adjustment methods that account directly for health status promise to reduce incentives to exclude children with chronic illnesses from managed care plans and to provide a foundation for more appropriate payments to pediatricians who care for these children.
Adolescent↗
Posttraumatic stress, depression, and health among older adults in primary care.
OBJECTIVE: The authors examined 1) rates of trauma and posttraumatic stress (PTS) in older adults in primary care; 2) factors related to more posttraumatic stress symptoms; and 3) the influence of posttraumatic stress and depression on health perceptions and negative health behaviors (i.e., suicidal ideation, smoking, and at-risk drinking). METHODS: As part of participation in a study at the Philadelphia VAMC and the University of Pennsylvania, a random subset (N = 2,718) of older adults (age > or = 65 years) with scheduled primary care visits were screened concerning demographics, the General Health Questionnaire-12, suicidal thoughts, alcohol consumption, cigarette smoking, perceived health status, PTS, and cognitive impairment. RESULTS: The rate of trauma in older adult primary care patients was high in both the VA (37%) and university-based clinics (24%). Many older adults reported interference from at least one of the three posttraumatic stress items assessed (VA, 18%; university-based primary care, 8%). In a model including demographic factors, higher PTS and depression were uniquely related to more negative health perceptions. In a model including demographic factors, both higher PTS and depression were uniquely related to higher likelihood of suicidal ideation. In contrast, PTS no longer contributed to a model of smoking once depression was included. Neither PTS nor depression significantly contributed to a model of at-risk drinking. CONCLUSIONS: Trauma and posttraumatic stress are frequent and significant problems for older adults in primary care. Both posttraumatic stress and depression are related to more negative health perceptions and higher likelihood of suicidal ideation.
Aged↗
The cohort feedback model with symmetric net maternity.
"In this paper we consider the simplest and most widely used demographic feedback model, the birth-response cohort feedback model. In the case of symmetric net maternity, we put the model into a form in which one of the rare global bifurcation theorems in the mathematical literature can be brought to bear. As a consequence, we prove that the model has solutions with period exactly twice the mean age of net maternity for at least a specified range of parameter values which include cycles of non-infinitesimal amplitude." (SUMMARY IN FRE)
Age Factors↗
Test of a behavior-based individual-based model: response of shorebird mortality to habitat loss.
In behavior-based individual-based models (IBMs), demographic functions are emergent properties of the model and are not built into the model structure itself, as is the case with the more widely used demography-based IBMs. Our behavior-based IBM represents the physiology and behavioral decision making of individual animals and, from that, predicts how many survive the winter nonbreeding season, an important component of fitness. This paper provides the first test of such a model by predicting the change in winter mortality of a charadriid shorebird following removal of intertidal feeding habitat, the main effect of which was to increase bird density. After adjusting one calibration parameter to the level required to replicate the observed mortality rate before habitat loss, the model predicted that mortality would increase by 3.65%, which compares well with the observed increase of 3.17%. The implication that mortality was density-dependent was confirmed by predicting mortality over a range of bird densities. Further simulations showed that the density dependence was due to an increase in both interference and depletion competition as bird density increased. Other simulations suggested that an additional area of mudflat, equivalent to only 10% of the area that had been lost, would be needed by way of mitigation to return mortality to its original level. Being situated at a high shore level with the flow of water in and out impeded by inlet pipes, the mitigating mudflat would be accessible to birds when all mudflats in the estuary were covered at high tide, thus providing the birds with extra feeding time and not just a small replacement mudflat. Apart from providing the first, and confidence-raising, test of a behavior-based IBM, the results suggest (1) that the chosen calibration procedure was effective; (2) that where no new fieldwork is required, and despite being parameter rich, a behavior-based IBM can be parameterized quickly (few weeks), and thus cheaply, because so many of the parameter values can be obtained from the literature and are embedded in the model; and (3) that behavior-based IBMs can be used to explore system behavior (e.g., the role of depletion competition and interference competition in density-dependent mortality).
Animals↗
An econometric test of structural change in the demographic transition.
"The structural change model of the demographic transition developed by Easterlin and others is explored empirically by applying the Brown, Durbin and Evans test of structural change to annual data from the transitions of Sweden, Norway, England and Wales, and Finland. The evidence strongly supports the structural change model over traditional models (based on gradual changes in explanatory variables), indicating a supply response of fertility to declining illness and death during the early stages of transition, and a demand response to the death of children during the latter stages, when families are likely to have achieved desired size."
Demography↗
Developing a predictive model for vertigo using demographic and laboratory data: An evidence-based medicine approach.
CONCLUSION: The approach described in this paper may be helpful in establishing an early-warning, evidence-based mechanism for diagnosing vertigo, which can be utilized in medical education to reduce medical uncertainty. OBJECTIVE: To use an evidence-based medicine approach to evaluate the probability of having vertigo using laboratory and demographic data. MATERIAL AND METHODS: The study was conducted on 22 working days during July 2002. Targeted cases who visited a general hospital in southern Taiwan for routine physical examinations were asked to participate in the study and agreed to take additional tests during their visits. A total of 200 subjects were systematically and randomly selected from this data pool. We ran binary logistic regression on all these cases. RESULTS: The logistic regression model explained 71.3% of the variance in having vertigo or not. The equation for having vertigo was as follows: -21.855 + (1.132 x male gender) + (0.071 x age) + (-0.023 x systolic blood pressure) + (0.057 x diastolic blood pressure) + (0.048 x fasting glucose) + (0.051 x cholesterol) + (-0.005 x triglycerides) + (-0.361 x presence of cardiovascular diseases).
Adult↗
Use of diagnosis-based risk adjustment models to predict individual health care expenditure under the National Health Insurance system in Taiwan.
BACKGROUND AND PURPOSE: Diagnostic information has been extensively studied and employed in the prediction of risk adjusted capitation payments in some countries. Nevertheless, few studies have been dedicated to the development of diagnosis-based risk adjusters in Taiwan. The purposes of this study were to develop outpatient diagnosis-based risk adjusters for a model of Taiwan's National Health Insurance (NHI) system and to evaluate the predictability of the risk adjustment models generated utilizing these adjusters. METHODS: Using a 2% random sample of 371,620 NHI enrollees, 5 risk adjustment models--i.e., demographic, inpatient diagnostic information outpatient diagnostic information, full diagnostic information, and prior utilization models--were evaluated with respect to predictive R2 and predictive ratios. While inpatient diagnosis-based risk adjusters were borrowed from previous research, outpatient diagnosis-based risk adjusters, referred to as Taiwan Ambulatory Spending Groups (TASGs), were developed based on 1996 claims data. RESULTS: The values of predictive R2 for the 5 risk adjustment models showed that the inclusion of outpatient diagnostic information considerably improved the predictability of the risk adjustment models for Taiwan's NHI system. Moreover, the predictive ratios revealed that the full diagnostic information model would reimburse different risk subgroups more fairly than the demographic, inpatient diagnostic information, and outpatient diagnostic information models and also outperform the prior utilization model with respect to disease risk groups. CONCLUSIONS: The risk adjustment model including the TASG risk adjusters can significantly improve predictability and can be employed to assess the NHI's current and proposed reform measures.
Capitation Fee↗
Uncertainties in predicting the demographic impact of AIDS.
A model giving the demographic impact of AIDS is analysed to examine the sensitivity of the projections when various complicating features are included. The model deals with age and sexual partner change rate as continuous variables and uses a device to specify arbitrary correlations between the ages of the people who form sexual partnerships. The device ensures consistency, in that the amount of partner formation is the same regardless of whether the partnerships are counted from the point of view of males or females. Arbitrary correlation between partner change rate and fertility is also permitted. The results show the uncertainty in model predictions that population growth will reduce over the next 20 years to approximately zero in parts of East Africa severely affected by the AIDS epidemic. The main sources of uncertainty in the model predictions are assumptions concerning the correlation between ages in a partnership, the correlation between partner change rate and fertility, the incubation period of AIDS, and the variability of the female partner change rate.
Acquired Immunodeficiency Syndrome↗
Multiyear diagnostic information from prior hospitalization as a risk-adjuster for capitation payments.
As part of a move toward a more market-oriented health-care system, major changes have been implemented in the Dutch social health insurance system. The competing sickness funds now receive risk-adjusted capitation payments, currently based on the age-sex distribution of the insurance portfolios. These very crude health indicators do not reflect expected costs accurately. The authors examine whether the incorporation of inpatient diagnostic information over a multiyear period can increase the accuracy of the capitation model. Using a panel data set (n approximately 50,000) comprising annual costs and diagnostic information for 5 successive years, the authors compare demographic and diagnostic models in their ability to predict future health care costs. The predictive accuracy of an age-sex-based capitation formula improves substantially when diagnostic information from an individual's prior hospitalizations is used as an additional risk-adjuster. The longer the period over which diagnostic information is available, the better is the predictive accuracy. The expected loss in 1992 for insured persons with the highest costs in 1988 decreases from 88% (demographic model) to 62% (1-year diagnostic model) and to 43% (3-year diagnostic model). The use of diagnostic information from prior hospitalizations is a promising option for improving the capitation formulae. The authors' results are relevant not only for situations where competing insurers are capitated, as in the Netherlands, but also when providers (United Kingdom) or health maintenance organizations (United States) are capitated.
Adult↗
Comment on D. Loschky and W. Wilcox's "Demographic transition: a forcing model".
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Birth Rate↗
Sleep problems in the community elderly as predictors of death and nursing home placement.
In 1984-85, 1855 elderly residents of an urban community responded to a comprehensive baseline interview that included questions regarding an extensive set of sleep characteristics and problems. During the subsequent 3 1/2 years of follow-up, 16.7% of the respondents died and 3.5% were placed in nursing homes. The predictive significance of each sleep characteristic for mortality and for nursing home placement was determined separately for males and females, using Cox proportional hazards models. Selected demographic and psychosocial variables were also entered into the models. Age, problems with activities of daily living (ADL), self-assessed health, income, cognitive impairment, depression and whether respondents were living alone were controlled for statistically. Of the many variables analyzed, in males insomnia was the strongest predictor of both mortality and nursing home placement. For mortality, the relative hazard associated with insomnia exceeded the hazards associated with age, ADL problems, fair-poor health and low income. For nursing home placement, the hazard associated with insomnia exceeded that associated with cognitive impairment. The relationships of insomnia to mortality and nursing home placement were U-shaped, with a worse outcome if insomnia complaints over the preceding 2 weeks were either prominent (numerous or frequent) or absent. For females, insomnia was a borderline predictor of mortality and did not predict nursing home placement at all. Symptoms of the restless legs syndrome predicted mortality for females in some Cox regression models. Reported sleep duration, symptoms of sleep apnea and frequent use of hypnotic drugs did not predict mortality or nursing home placement in either sex.
Aged↗
The loglinear model as a tool for the analysis of demographic data.
The author discusses the use of loglinear models in demographic analysis, particularly with regard to the analysis of contingency tables. Their use is illustrated using data from the 1980 World Fertility Survey for Sudan to analyze the determinants of fifth-birth intervals. The results show "the ability of the technique to improve our understanding of the mechanism of fertility differentials using individual--instead of aggregate--data. It has shown how each variable affects the process when all other variables are held constant."
Africa↗
Predictors of dental pain and general anesthetic receipt for hospital dental procedures among New Zealand children.
OBJECTIVES: To predict experience of dental pain and hospital dental general anesthetic receipt among Mäori, Pacific and New Zealand European or Other (NZEO) children in New Zealand. METHODS: Data were from the 2002 National Child Nutrition Survey. Models representing demographic, socio-economic status (SES), lifestyle, dietary, food security and oral health paradigms were tested using logistic regression. RESULTS: Some 3275 children participated; 37.4% Mäori, 32.3% Pacific and 30.3% NZEO. Mäori children had higher odds of dental pain experience than NZEO children after adjusting for age, sex and length of time lived in New Zealand and with addition of household SES or physical factors. There were no differences in Pacific and NZEO child dental pain experience when the same factors were accounted for. The prevalence of dental general anesthetic receipt was similar among Mäori, Pacific and NZEO children after adjusting for demographic, lifestyle, dietary, food security and dental factors in separate models. When such factors were investigated together, Pacific children were less likely to have received a dental general anesthetic than NZEO children. CONCLUSIONS: Mäori children were more likely to experience dental pain and Pacific children were less likely to have received a dental general anesthetic than NZEO children after accounting for various behavioral and material factors. The latter may reflect issues pertaining to access and culturally insensitive services rather than demand for care per se.
Adolescent↗