Gas cooking is associated with small reductions in lung function in children.

Inconsistent effects of gas cooking on lung function have been reported. In a previous study from Austria, we demonstrated a significant, though small, reduction of lung function parameters in children living in homes with gas stoves. We used a larger international database to check if this finding can be generalised. To study the relative impact of cooking with gas on lung function parameters of primary school children in a wide range of geographical settings, we analysed flow and volume data of approximately 24,000 children (aged 6-12 yrs) from nine countries in Europe and North America. Exposure information was obtained by comparable questionnaires and spirometry according to an American Thoracic Society/European Respiratory Society protocol. Linear regressions were used, controlling for individual risk factors and study area. Heterogeneity between study-specific results and mean effects were estimated using meta-analytical tools. On average, gas cooking reduced lung function parameters. Overall effects were small (-0.1-0.7%) and only significant for forced vital capacity and forced expiratory volume in 1 s. There was some indication that allergic children were more affected by gas cooking. Under current housing conditions, gas cooking is associated with only small reductions in lung function.

The effect of some N solutions for parenteral nutrition on gastric and pancreatic secretion.

In patients without pancreatic disease Aminofusin L forte infused for 1 h did not stimulate gastric or pancreatic secretion. On the other hand, infusion of casein by hydrolysate led to a significant increase in the concentration and total output of HCl. 4 h intravenous infusion of Aminofusin L forte caused a transient but significant rise of the bicarbonate concentration, amylase activity and above all trypsin activity and output. The results show that N solutions used for parenteral protein nutrition influence in a different way both gastric and pancreatic secretion.

Childhood respiratory symptoms, hospital admissions, and long-term exposure to airborne particulate matter.

The effects of long-term exposure to air pollution on respiratory symptoms and respiratory hospitalization (for asthma, bronchitis or pneumonia) were assessed in a cross-sectional study of children (ages 7--11 years, N=667) living in a moderately industrialized city in Central Slovakia. Individual health, residence and family history data obtained through the CESAR study were coupled, using Geographic Information System (GIS) technologies, with total suspended particulate (TSP) exposure estimates derived from dispersion modeling of almost all local stationary sources. These data were used to assess, at the intra-city level and child-specific level, the potential for TSP as a risk factor for respiratory disease in children. TSP, PM10, and PM2.5 monitored ambient concentrations are highly correlated in the study location. Modeled TSP concentrations resulting from local source emissions are dominated by a large wood processing facility, suggesting variation in exposures among children. The prevalence of respiratory non-asthmatic symptoms and hospitalizations was associated with increased TSP. No association between long-term exposure to TSP and asthma diagnosis or wheeze symptoms was found. Logistic regression modeling indicated a significant increase in hospital admissions for asthma, bronchitis or pneumonia associated with increasing air pollution (OR 2.16, CI, 1.01--4.60), doctor-diagnosed bronchitis (OR 1.53, CI, 1.02-2.30), and parent-reported chronic phlegm (OR 3.43, CI, 1.64--7.16), expressed as odds for a 15 microg/m3 increase in estimated TSP exposure, and these increases are not due to differences in socio-economic, health care or other identified factors.

Personal exposure to particles in Banská Bystrica, Slovakia.

Epidemiological studies have associated adverse health impacts with ambient concentrations of particulate matter (PM), though these studies have been limited in their characterization of personal exposure to PM. An exposure study of healthy nonsmoking adults and children was conducted in Banska Bystrica, Slovakia, to characterize the range of personal exposures to air pollutants and to determine the influence of occupation, season, residence location, and outdoor and indoor concentrations on personal exposures. Twenty-four-hour personal, at-home indoor, and ambient measurements of PM10, PM2.5, sulfate (SO4(2-)) and nicotine were obtained for 18 office workers, 16 industrial workers, and 15 high school students in winter and summer. Results showed that outdoor levels of pollutants were modest, with clear seasonal differences: outdoor PM10 summer/winter mean = 35/45 microg/m3; PM2.5 summer/winter mean = 22/32 microg/m3. SO4(2-) levels were low (4-7 microg/m3) and relatively uniform across the different sample types (personal, indoor, outdoor), areas, and occupational groups. This suggests that SO4(2-) may be a useful marker for combustion mode particles of ambient origin, although the relationship between personal exposures and ambient SO4(2-) levels was more complex than observed in North American settings. During winter especially, the central city area showed higher concentrations than the suburban location for outdoor, personal, and indoor measures of PM10, PM2.5, and to a lesser extent for SO4(2-), suggesting the importance of local sources. For PM2.5 and PM10, ratios consistent with expectations were found among exposure indices for all three subject groups (personal>indoor>outdoor), and between work type (industrial>students>office workers). The ratio of PM2.5 personal to indoor exposures ranged from 1.0 to 3.9 and of personal to outdoor exposures from 1.6 to 4.2. The ratio of PM10 personal to indoor exposures ranged from 1.1 to 2.9 and the ratio of personal to outdoor exposures from 2.1 to 4.1. For a combined group of office workers and students, personal PM10/PM2.5 levels were predicted by statistically significant multivariate models incorporating indoor (for PM2.5) or outdoor (for PM10) PM levels, and nicotine exposure (for PM10). Small but significant fractions of the overall variability, 15% for PM2.5 and 17% for PM10, were explained by these models. The results indicate that central site monitors underpredict actual human exposures to PM2.5 and PM10. Personal exposure to SO4(2-) was found to be predicted by outdoor or indoor SO4(2-) levels with 23-71% of the overall variability explained by these predictors. We conclude that personal exposure measurements and additional demographic and daily activity data are crucial for accurate evaluation of exposure to particles in this setting.

Methodological approaches to the analysis of hierarchical studies of air pollution and respiratory health--examples from the CESAR study. Central European Study on Air pollution and Respiratory Health.

OBJECTIVES: Many studies of air pollution and health are carried out over several geographical areas, and sometimes over several countries. This paper explores three approaches to analysis in such studies: a non hierarchical model, a two-stage analysis, and multilevel modelling. Illustrations are given using a preliminary subset of data from the CESAR study. DESIGN: The Central European Study on Air pollution and Respiratory Health (CESAR) was conducted in 25 areas within six Central European countries, enrolling 20,271 schoolchildren. Pollution averages were calculated for each area. Associations between pollution and health outcomes were estimated under different models. MAIN RESULTS: A regression analysis of log FVC (forced vital capacity) on PM10, ignoring the geographical hierarchy, estimated a significant mean drop in FVC (adjusted for confounders) of 2.2% (95% CI 0.5% to 1.3%), p=0.007, from the area with the lowest PM10 to that with the highest. A multilevel model (mlm), using data for all children, but with random effects at area and country level, estimated a drop of 2.8% (-0.6% to 6.1%), p=0.110. A two-stage analysis (mean log FVC, adjusted for confounders, was estimated for each area using regression, and these means then regressed on PM10) estimated a drop of 2.6% (-0.5% to 5.5%), p=0.101. Simulation exercises showed the non hierarchical method to be very inadequate in the context of the CESAR study, with only half of all 95% confidence intervals for the estimated PM10 slope containing the true value (i.e., that used to create the simulated data). The two-stage and multilevel modelling methods gave results which were substantially better, though both underperformed slightly. All three methods appeared to give unbiased slope estimates. CONCLUSIONS: Acknowledgement of hierarchical structures is essential in statistical inference--standard errors can be substantially incorrect when they are ignored. Multilevel, random-effects models correctly address hierarchical structures, though having few units at higher levels can cause problems in convergence, especially where complex modelling is required. Two-stage analyses, acknowledging hierarchy, provide simple alternatives to random-effects models.

Effect of hyper- and hypothyroidism on the alpha-tocopherol concentration in serum and some organs of growing rats.

The finding of a raised alpha-tocopherol concentration in the heart muscle, liver, skeletal muscle and serum during experimental hyperthyroidism, lasting 30 days, made the authors assume that this cumulation is a transient phenomenon which would disappear during a prolonged metabolic disorder as a result of energetic breakdown of the organism. The purpose of the paper was to verify this view. The investigation with experimental hyper- and hypothyroidism was made in 120 rats with a mean weight of 160 g. To 60 animals daily 100 mug thyroxin were administered by the i.p. route, 48 animals were given 2.5 Carbimazol daily by mouth to induce hypothyroidism and 12 animals served as controls. The animals were fed the same diet. The effect of the administered preparations was examined after 20, 30, 40, 50 and 60 days. In hypothyroid animals the 50th day was omitted. The results revealed: 1. In hyperthyroid animals the body weight was almost constant to the end of the experiment. However these animals had a significantly raised weight of the heart muscle and liver, as compared with the remaining two groups. 2. In hyperthyroid animals the highest alpha-tocopherol concentration in the heart muscle and skeletal muscle was recorded after 20 days. During subsequent time intervals the alpha-tocopherol concentration in the heart muscle declined gradually. In the skeletal muscle a dramatic decline occurred after 40 days and proceeded to the end of the investigation when the recorded values were at the borderline of detectability. This finding confirmed the authors view that the alpha-tocopherol cumulation in muscle exposed to an increased work load is a transient phenomenon and disappears during prolonged hyperthyroidism before the breakdown of the organism. 3. In hyperthyroidism no correlation was found between the alpha-tocopherol concentration and the lipid content of organs and skeletal muscle. This correlation was found in hypothyroidism. 4. The alpha-tocopherol serum level in hyperthyroidism was significantly higher than in hypothyroidism. 5. In hyperthyroidism the alpha-tocopherol cumulation in liver increased gradually, and reached its maximum after 50 days. At a time when the alpha-tocopherol concentration in the heart muscle and skeletal muscle declined already, its liver concentration increased. This phenomenon may be associated with the increasing protein synthesis in the liver during hyperthyroidism, or with other phenomena which call for further investigation.

Effect of ascorbic acid on plasma cholesterol in humans in a long-term experiment.

During the period of a low vitamin C intake (approximately equal to 20 mg per day) ascorbic acid in a dose of 2 x 500 mg per day was administered to 82 men and women aged 50-75 years. A correlation of plasma cholesterol levels determined before and after a three months' administration of ascorbic acid showed the effect of vitamin C to be dependent on the starting concentration of plasma cholesterol: the higher the initial cholesterolemia, the greater the hypocholesterolemic effect of ascorbic acid. On restricting the experimental group to subjects with an initial cholesterolemia above 230 mg%, the effect of the same dose of ascorbic acid on cholesterolemia was followed in three-month periods for a further 9 months. In all these time intervals, ascorbic acid was found significantly to depress cholesterolemia and its effects persisted 6 weeks after termination of the experiment. The administration of 2 x 500 mg ascorbic acid daily during one year resulted in an abrupt increase of ascorbemia and a marked accumulation of ascorbic acid in the leucocytes. Six weeks following interruption of ascorbic acid intake, vitamin C concentration in the leucocytes significantly declined but still continued to be twice higher than in the control receiving no ascorbic acid supplement.

Hypocholesterolemic effect of ascorbic acid in maturity-onset diabetes mellitus.

A significantly lower vitamin C concentration has been found in the blood and particularly in the leukocytes of hypercholesterolemic diabetic patients than of healthy blood donors. Ascorbic acid administered in a dose of 500 mg per day for 12 months to metabolically stabilized hypercholesterolemic subjects with maturity-onset diabetes mellitus (diabetic diet without insulin or diabetic drugs) brought about a striking decline of cholesterolemia and a moderate decline of triglyceridemia. The serum lipid level in the control group given placebo remained unaltered. A daily administration of 500 mg of ascorbic acid for six months failed to affect the fasting level of serum immunoreactive insulin. It is assumed that the long-term administration of ascorbic acid to maturity-onset diabetics removed the tissue ascorbate deficiency and improved the liver ability to compensate the increased endogenous synthesis of cholesterol by its enhanced transformation to bile acids.

Health risk assessment for inhalation exposure to arsenic.

Health risk assessment was used as the formal process to estimate the likelihood and magnitude of the health effects occurring in humans as a result of environmental and occupational exposure to polluting agents. This study was focused at estimating the human health risk of the general and working population living in the region polluted by arsenic for more than 40 years, from combustion of coal with high arsenic content in the power plant. The exposure to arsenic from inhalation was under investigation. A study period of 40 years (1973-1993) was chosen. The study period was defined taking into account, besides the availability of data, the temporal patterns of the technological processes and the trends over time of environmental concentrations. The results from the arsenic risk assessment study were used for the evaluation of the health risk for different population groups in the polluted areas and for different professions of workers exposed to As in a power plant. The results are applicable for the evaluation of risk in real conditions, for health surveillance and for remedial changes and a potential suggestion on technological improvement.

Immune system parameters in children of Central and Eastern Europe: the CESAR study.

OBJECTIVE: of this paper is to compare observed values of immune parameters obtained in the CESAR study (The Central Europe Study of Air Pollution and Respiratory Health, funded by EC PHARE program) with ranges derived from other large population-based studies. STUDY DESIGN: Data were collected in healthy school children aged 9-11 years, in 6 countries: Bulgaria, the Czech Republic, Hungary, Poland, Romania and the Slovak Republic with the same standard approach in 1996. Random samples of 85 children per country, from 19 communities were selected from children having completed the health questionnaire, in total 495 children were analyzed. Lymphocyte subsets were determined by two-colour flow cytometric immunophenotyping using the lysed whole blood method (Becton-Dickinson). For determination of immunoglobulin concentration in sera nephelometric method (Behring Nephelometer system) was used. RESULTS: Medians, (5th-95th percentiles) of the lymphocyte subsets absolute count (x 10(9)/l) were as follows: CD19+ B cells 0.36 (0.13-0.66), total CD3+ T cells 1.74 (0.98-2.90), CD3+CD4+ helper-inducer T cells 0.95 (0.47-1.78), CD3+CD8+ suppressor/cytotoxic T cells 0.71 (0.38-1.22), CD3-CD16+56+ NK cells 0.36 (0.14-0.78), and for CD3+CD4+/CD3+CD8+ ratio 1.4 (0.8-2.4). Medians, (5th-95th percentiles) of percentages of lymphocyte subpopulations (%) were as follows: CD19+ B 13 (7-22), CD3+ T 70 (59-80), CD3+CD4+ T 38 (27-48), CD3+CD8+ T 28 (20-39), CD3-CD16+56+ NK cells 14 (6-27). Medians, (2.5th-97.5th percentiles) of the total immunoglobulin [g/l] were 11.7 (7.4-18.2) for IgG, 1.2 (0.5-2.5) for IgM, and 1.5 (0.5-3.4) for IgA. Based on the aspects of the size of the CESAR immune biomarker study and on the use of the standardized protocols we recommend to use the reference ranges on lymphocyte subsets and immunoglobulin in Europe as provided by this study.

[Vitamin C and psychomotor reactivity]. / Vitamin C i psikhomotornaia reaktivnost'.

The effect of vitamin C on the activity of the brain was studied. In groups of workers well provided for with vitamin C allowances a reduced number of industrial traumas was noted, which can be attributed to a greater concentration of attention and better reactivity. This could be achieved by administering daily doses of 100-150 mg of vitamin C. Workers engaged in night shifts were found to show improved psychotechnical test results with an ascorbinemia level of over 0.5 mg%. In a group of volunteers aged 16 to 18 years the results of psychomotor tests improved after a 14-day daily taking of 1000 mg of the vitamin C.