This article synthesizes two GIS-based accessibility measures into one framework, and applies the methods to examining spatial accessibility to primary healthcare in the Chicago 10-county region. The floating catchment area method defines the service area of physicians by a threshold travel time while accounting for the availability of physicians by their surrounded demands. The gravity-based method considers a nearby physician more accessible than a remote one and discounts a physician's availability by a gravity-based potential. The former is a special case of the latter. Based on the 2000 Census and primary care physician data, this research assesses the variation of spatial accessibility to primary care in the Chicago region, and analyzes the sensitivity of results by experimenting with ranges of threshold travel times in the floating catchment area method and travel friction coefficients in the gravity model. The methods may be used to help the U.S. Department of Health and Human Services and state Health Departments improve health professional shortage areas designation.

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Measures of Spatial Accessibility to Health Care in a GIS Environment: Synthesis and a Case Study in the Chicago Region:

From 1951 to 1955 serum cholesterol levels were measured in 1959 men and 2415 women aged between 31 and 65 years who were free of cardiovascular disease (CVD) and cancer. Under age 50 years, cholesterol levels are directly related with 30-year overall and CVD mortality; overall death increases 5% and CVD death 9% for each 10 mg/dL. After age 50 years there is no increased overall mortality with either high or low serum cholesterol levels. There is a direct association between falling cholesterol levels over the first 14 years and mortality over the following 18 years (11% overall and 14% CVD death rate increase per 1 mg/dL per year drop in cholesterol levels). Under age 50 years these data suggest that having a very low cholesterol level improves longevity. After age 50 years the association of mortality with cholesterol values is confounded by people whose cholesterol levels are falling—perhaps due to diseases predisposing to death. (JAMA1987;257:2176-2180)

https://jamanetwork.com/HttpHandlers/ArticlePdfHandler.ashx?journal=JAMA&articleId=365739&pdfFileName=jama_257_16_027.pdf

Cholesterol and Mortality: 30 Years of Follow-up From the Framingham Study

Serum gamma-glutamyl transferase (GGT) has been widely used as an index of liver dysfunction and marker of alcohol intake. The last few years have seen improvements in these areas and advances in understanding of its physiological role in counteracting oxidative stress by breaking down extracellular glutathione and making its component amino acids available to the cells. Conditions that increase serum GGT, such as obstructive liver disease, high alcohol consumption, and use of enzyme-inducing drugs, lead to increased free radical production and the threat of glutathione depletion. However, the products of the GGT reaction may themselves lead to increased free radical production, particularly in the presence of iron. There have also been important advances in the definition of the associations between serum GGT and risk of coronary heart disease, Type 2 diabetes, and stroke. People with high serum GGT have higher mortality, partly because of the association between GGT and other risk factors and partly because GGT is an independent predictor of risk. This review aims to summarize the knowledge about GGT's clinical applications, to present information on its physiological roles, consider the results of epidemiological studies, and assess how far these separate areas can be combined into an integrated view.

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Gamma Glutamyl Transferase

Although the literature on epidemiological associations between plasma triglyceride and CHD is not completely consistent, trends do emerge from the studies described here. First, the majority of observational studies demonstrate a significant univariate relation, although the results of case-control and cross-sectional studies are more uniform than those from prospective study designs. In many but not all studies, triglyceride remains a significant predictor of CHD in multivariate statistical analyses after controlling for TC or LDL-C. Perhaps the least consistent result is that the triglyceride association does not persist in some analyses controlling for HDL-C, while in other studies, the association remains significant. Although most studies have been conducted in men, the studies providing data on women, normocholesterolemic subjects, and diabetic subjects have generally found triglyceride to be, at the very least, a univariate risk factor. The results of intervention trials differ considerably, but no such study to date has been specifically designed to evaluate triglyceride-lowering effects on primary prevention of CHD. Important statistical properties must be taken into consideration in evaluating triglyceride as a risk factor for CHD. The large variability of triglyceride measurements and the correlation of triglyceride values with other lipid measures appears to result in the underestimation of the association between triglyceride and disease in multivariate analyses. Finally, individual genetic susceptibility may play an important role in the relation between plasma triglyceride levels and CHD. For example, risk of CHD clearly varies among the well-established familial forms of hypertriglyceridemia. A predominance of small, dense, LDL particles (LDL subclass pattern B) also appears to be a genetic trait associated with both increased risk of MI and increases in plasma triglyceride levels.

Plasma triglyceride and coronary heart disease.

The primary role of cellular gamma glutamyltransferase (GGT) is to metabolize extracellular reduced glutathione (GSH), allowing for precursor amino acids to be assimilated and reutilized for intracellular GSH synthesis. Paradoxically, recent experimental studies indicate that cellular GGT may also be involved in the generation of reactive oxygen species in the presence of iron or other transition metals. Although the relationship between cellular GGT and serum GGT is not known and serum GGT activity has been commonly used as a marker for excessive alcohol consumption or liver diseases, our series of epidemiological studies consistently suggest that serum GGT within its normal range might be an early and sensitive enzyme related to oxidative stress. For example, serum and dietary antioxidant vitamins had inverse, dose-response relations to serum GGT level within its normal range, whereas dietary heme iron was positively related to serum GGT level. More importantly, serum GGT level within its normal range positively predicted F2-isoprostanes, an oxidative damage product of arachidonic acid, and fibrinogen and C-reactive protein, markers of inflammation, which were measured 5 or 15 years later, in dose-response manners. These findings suggest that strong associations of serum GGT with many cardiovascular risk factors and/or events might be explained by a mechanism related to oxidative stress. Even though studies on serum and/or cellular GGT is at a beginning stage, our epidemiological findings suggest that serum GGT might be useful in studying oxidative stress-related issues in both epidemiological and clinical settings.

Is serum gamma glutamyltransferase a marker of oxidative stress

The health workforce has a dynamically changing nature and the regular documentation of the distribution of health professionals is a persistent policy concern. The aim of the present study was to examine available human medical resources in primary care and identify possible inequalities regarding the distribution of general practitioners in Albania between 2000 and 2004. With census data, we investigated the degree of inequality by calculating relative inequality indices. We plotted the Lorenz curves and calculated the Gini, Atkinson and Robin Hood indices and decile ratios, both before and after adjusting for mortality and consultation rates. The Gini index for the distribution of general practitioners in 2000 was 0.154. After adjusting for mortality it was 0.126, while after adjusting for consultation rates it was 0.288. The Robin Hood index for 2000 was 11.2%, which corresponds to 173 general practitioners who should be relocated in order to achieve equality. The corresponding figure after adjusting for mortality was 9.2% (142 general practitioners), while after adjusting for consultation rates the number was 20.6% (315). These figures changed to 6.3% (100), 6.3% (115) and 19.8% (315) in 2004. There was a declining trend in the inequality of distribution of general practitioners in Albania between 2000 and 2004. The trend in inequality was apparent irrespective of the relative inequality indicator used. The level of inequality varied depending on the adjustment method used. Reallocation strategies for general practitioners in Albania could be the key in alleviating the inequalities in primary care workforce distribution.

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Measuring health inequalities in Albania: A focus on the distribution of general practitioners

The causes of premature death and the associated risk factors were analysed in a cohort of 7935 middle aged men participating in a preventive population programme in Malmo. They were screened when aged 46-48 and then followed up for 3½-8 years. Two hundred and eighteen died, of whom 181 (83%) underwent necropsy. Three major causes of death were established: cancer in 61 (28%), deaths related to consumption of alcohol in 55 (25%), and coronary heart disease in 50 (23%). Distinctly different patterns of risk factors were found to be associated with each of the three main causes of premature death. In death due to coronary heart disease smoking (p=0·0062), serum cholesterol concentration (p=0·00014), serum triglyceride concentration (p=0·00013), systolic blood pressure (p=0·000012), and diastolic blood pressure (p=0·0021) were the strongest single determinants but diastolic blood pressure ceased to be a predictive factor in a multivariate analysis whereas all the other variables could be combined in a highly predictive logistic model. In death related to consumption of alcohol equal or even stronger associations were found for serum γ glutamyltransferase activity (p Malignant diseases and diseases related to consumption of alcohol were at least as prominent as cardiovascular disorders in causing premature death in the cohort of men studied. All three types of conditions are potentially avoidable and seem to be associated with significant and distinctive patterns of risk factors. These patterns should be used, as blood pressure and serum lipid concentrations already are, to predict the risk of premature death and indicate preventive measures.

https://www.bmj.com/content/bmj/288/6426/1264.full.pdf

Risk factors for premature death in middle aged men

Aerial distance from the dependent Primary Health Center is a crude but objective measure of geographical accessibility to Primary Health care facilities. This report describes a method for calculation of distances between the PHC and the population it serves using the data available from the local health authorities and the Swedish Central Statistical Bureau. The Swedish annual population registration records of 1991 and the property register available with the Central Statistical Bureau of Sweden formed the main data sources. By coupling the address in the population register to the property register each individual was mapped to the centroid of a property. The location of the PHCs as well as the areas covered by each were obtained from the local health authorities and mapped. By intersecting the population coverage with the PHC coverage the population for each PHC area was identified. Subsequently the distance to the PHC was calculated for each individual (property centroid). The population maps so generated can be linked to other databases to visualize and analyze the spatial dimension of health and disease. The methodology can be adapted for use with postal code districts, census enumeration tracts, or any other small area.

Distance from the primary health center: a GIS method to study geographical access to health care

Premature death and associated risk factors in urban middle-aged men☆

The total, consecutive mortality in a population of 10,353 middle-aged males invited to participate in a preventive medical population program in Malmo was followed up 1.5-6.5 years, mean 4.5 years, after the time of invitation and analyzed in relation to participation or nonparticipation, forensic or in-hospital autopsy and possible intervention effects. The total mortality was twice as high in the nonparticipants as in the participants, and the death rate due to alcohol-related diseases was five times higher. There were no significant differences in other causes of death, including cancer and cardiovascular diseases. In the nonparticipants autopsied at the Forensic Department the proportion of alcohol-related deaths was 60.5%, compared with 10.0% in participants autopsied in hospital. A history of alcohol abuse was present in 45.2% of the total sample, and in 61.0% of the group autopsied at the Forensic Department. In participants with increased screening gamma-glutamyltransferase, mortality at 48-72 months' follow-up was lower in an intervention group in comparison with a control group matched for sex, age and gamma-glutamyltransferase. The results support findings that alcohol-related deaths, nonparticipation in a preventive population program, and intervention effects in a public health strategy against alcohol and its complications are major determinants of premature mortality in middle-aged urban males.

Major determinants of premature mortality in middle-aged urban males: alcohol-related deaths and degree of participation in a preventive population program against alcohol and its complications

Erik Trell

Papers

Measuring health inequalities in Albania: A focus on the distribution of general practitioners

Risk factors for premature death in middle aged men

Distance from the primary health center: a GIS method to study geographical access to health care

Premature death and associated risk factors in urban middle-aged men☆

Major determinants of premature mortality in middle-aged urban males: alcohol-related deaths and degree of participation in a preventive population program against alcohol and its complications