Population age structure and the cost of municipal waste collection. A case study from the Czech Republic.

Waste management is a common public service whose provision is the responsibility of local governments. As is usual with public services, the question of its efficiency naturally arises. The majority of studies focus on such efficiency from the perspective of the provider. This is based on the assumption that waste collection expenditure is a function of available equipment and municipal characteristics. In our opinion this approach has its limitations, and therefore we have used a novel approach based on the demand from municipal citizens for waste collection services. We build on previous results obtained from data concerning social and demographic characteristics, and focus on the relationship between age and expenditure on municipal solid waste, concentrating specifically on the ageing of the population. The ageing of societies in general is a very topical issue, but there is rather little focus in research on the effects of ageing on the demand for various public services. The research that does exist in the area of waste management that takes the age factor into account typically only makes a very rough division of the population into age categories such as children, people of working age and elderly people. Such wide groups naturally contain people with a large variety of needs, and therefore often lead to ambiguous results. The goal of our paper is to examine this topic in more detail, and to estimate the effects of various age categories of municipal citizens on municipal waste expenditure. We use models with age categories differentiated by decades, an approach which provides significantly more detailed information than the age variables used in other studies in this area. We use population age and waste management expenditure data collected from more than 6100 municipalities in the Czech Republic in 2011 and 2014. The results of our investigation have shown that senior citizens of a certain age (approximately at the onset of retirement) have a surprisingly strong influence on waste management expenditure.

Serum leptin in the development of insulin resistance and other disorders in the metabolic syndrome.

The metabolic syndrome mostly represented by obesity and hyperinsulinaemia connected with insulin resistance, presents the main mechanism in the pathogenesis of cardiovascular disease. The aim of this study was to analyze the interrelations between several metabolic variables (including leptin) and factors related to insulin resistance in groups of both normal and non-diabetic hyperlipemic postmenopausal women and men of appropriate age, and to attempt to elucidate the gender differences. Two groups of patients (20 men, 20 women) with hypertriglyceridemia were compared with 30 individuals (10 men, 20 women) with normal serum triacylglycerols. Fasting serum leptin concentration, lipid parameters (triacylglycerols, HDL cholesterol, LDL cholesterol) and BMI were measured and compared with changes in insulin parameters influencing insulin resistance (HOMA IR, insulin, intact proinsulin, C-peptide). Statistical analysis was performed using SAS/STAT software including unpaired Student's t-test, Kolmogorov-Smirnov's test, Spearman's rank-order correlation and multiple regression analysis. In men, the insulin sensitivity correlates with leptin only. In women insulin sensitivity is markedly influenced by a complex of factors: leptin and lipid parameters. Increased insulin resistance in men is followed mainly by the increased correlations between leptin, HOMA IR and insulin parameters. In women correlations between leptin, HOMA IR and insulin parameters were smaller, but the inverse correlation with HDL cholesterol was stronger. In postmenopausal women and also in men, serum leptin concentration contributes to insulin resistance. However in women the effect of increase in serum triacylglycerols in contribution of insulin resistance seems to be more dominant.

TNF-alpha in the development of insulin resistance and other disorders in metabolic syndrome.

Insulin resistance and obesity are very frequent disorders and are described as the dominant risk factors for cardiovascular disease. The aim of this study was to analyze the interrelations between several metabolic variables (including TNF-alpha) and factors related to insulin resistance in groups of both normal and hyperlipidemic postmenopausal women and men of appropriate age, and to attempt to elucidate the gender differences. The study was carried out on 70 out-patients of the Metabolic Center. From these, 40 patients (20 men and 20 women) were selected with mild hyperlipidemia. Two other groups (10 men and 20 women) with approximately normal serum lipids parameters were taken as "controls". In hyperlipidemic women the mean serum concentration of the TNF-alpha was no different from that in the control group in spite of the fact that values of HOMA IR, insulin, proinsulin and lipid parameters increased significantly. In hyperlipidemic men we have found the decrease in TNF-alpha in comparison with the control group. In all four groups the statistical analysis showed correlations between metabolic parameters (including TNF-alpha) and parameters related to insulin resistance. Also differences in relation to the gender have been found. Multiple regression analysis demonstrated the important role of TNF-alpha in the regulation of both the insulin resistance and in the secretion of insulin in women. In men, BMI and HDL-cholesterol played a dominant role, while the role of TNF-alpha seemed to be minimal.

Gender differences in factors influencing insulin resistance in elderly hyperlipemic non-diabetic subjects.

BACKGROUND: The increase in the prevalence of insulin resistance-related metabolic syndrome, a disorder that greatly increases the risk of diabetes, heart attack and stroke, is alarming. One of the most frequent and early symptoms of metabolic syndrome is hypertriglyceridemia. We examined the gender differences between various metabolic factors related to insulin resistance in elderly non-diabetic men and postmenopausal women of comparable age suffering from hypertriglyceridemia, and compared them with healthy subjects of equal age. RESULTS: The indexes of insulin resistance HOMA IR and QUICKI were significantly higher in both hyperlipemic men and women than in controls; 95% confidence limits of hyperlipemic subjects did not overlap with controls. In both normolipemic and hyperlipemic men and women serum leptin correlated significantly with insulin resistance, while HDL-cholesterol correlated inversely with HOMA-IR only in women (both normo- and hyperlipemic), and serum tumor necrosis factor alpha (TNFalpha) only in hyperlipemic women. According to results of multiple regression analysis with HOMA-IR as a dependent variable, leptin played a significant role in determining insulin resistance in both genders, but--aside from leptin--triglycerides, TNFalpha and decreased HDL-cholesterol were significant determinants in women, while body mass index and decreased HDL-cholesterol were significant determinants in men. The coefficient of determination (R2) of HOMA IR by above mentioned metabolic variables was in women above 60%, in men only about 40%. CONCLUSION: The significant role of serum leptin in determination of insulin resistance in both elderly men and postmenopausal women of equal age was confirmed. However, the study also revealed significant gender differences : in women a strong influence of triglycerides, TNFalpha and decreased HDL-cholesterol, in men only a mild role of BMI and decreased HDL-cholesterol.

Detection of insulin resistance by simple quantitative insulin sensitivity check index QUICKI for epidemiological assessment and prevention.

The aim of the present study was to evaluate the recently defined simple insulin sensitivity check index QUICKI (Katz et al. 2000) for insulin resistance diagnostics in common clinical and epidemiological practice. Both the QUICKI (1/log insulin + log glycemia in mg/dL) and HOMA (insulin * glycemia in micromol/L/22.5) indexes were calculated from fasting values in 259 adult healthy volunteers and patients, and in 47 healthy and obese children of prepubertal age of both sexes. In adults, a fall in the QUICKI index (mean +/- SEM in healthy subjects = 0.366 +/- 0.029) as well as an increase in the HOMA index (in healthy subjects 1.57 +/- 0.87) corresponded to metabolic and clinical manifestations of insulin resistance in various groups of outpatients. The QUICKI index had lower dispersion variances and the 95% confidence limits displayed a higher discrimination capacity. Patients with glucose intolerance or diabetes, hyperlipidemia typical for insulin resistance, or with combination of these metabolic disorders were characterized by QUICKI index values that were significantly lower than those of healthy volunteers. The QUICKI index in healthy prepubertal children indicated a higher insulin resistance compared to adults (mean 0.339 +/- 0.020); an increase in the QUICKI index in obese children with BMI over 25 was not significant, although obese children showed a significant increase of serum leptin and triglycerides and a decrease of HDL-cholesterol. Adult patients with QUICKI index below 0.357 (which is at the lower limit of 95% confidence limits in healthy persons) represented a group with typical manifestations of metabolic syndrome, differing in these parameters significantly from the group of patients of comparable age with a QUICKI index greater than 0.357. The present study suggests suitability of the QUICKI index for diagnosis of insulin resistance in clinical and epidemiological practice. However, a normal QUICKI index range needs to be established for each laboratory with an appropriate control group because of significant interlaboratory variations in insulin determinations and/or possible differences in various populations.