B Kriz

SMALL AREA VARIATIONS IN AMBIENT NO2 CONCENTRATIONS IN FOUR EUROPEAN AREAS

Abstract Spatial variations in urban air pollution are of considerable significance both because of the growing evidence for associations between exposure and human health and because of the increasing requirement for action to control and reduce levels of air pollution. This study examines sources and patterns of variation in NO2, as a marker for traffic-related pollution, in four predominantly urban study areas: Amsterdam (Netherlands), Huddersfield (UK), Poznan (Poland) and Prague (Czech Republic). Data on pollution levels were collected using passive samplers, deployed in duplicate for 2 week periods on four occasions over one year. Mixed-effect modelling was used to explore the magnitude of between-survey, between-site and between-sampler and interaction effects, and to provide a measure of mean annual concentration at each sample site. Measured concentrations varied significantly between different surveys, with a tendency to be higher in winter months. Strong correlations were seen, however, between monitored concentrations in successive surveys, suggesting that the geographic pattern of variation in all areas was essentially stable over time. Between-sampler variation was seen to be small (CV generally 5–8%), indicating that the samplers provided consistent measures of NO2 concentrations. There were also strongly significant between-site and site–survey interaction effects. Between-site variation accounted for between 61% (Poznan) and 84% (Prague) of total observed variation; expressed as a coefficient of variation, between-site variation was least in Amsterdam, the smallest and most uniform study area (22%), and greatest in Prague (42%). The modelled mean annual NO2 concentration, derived from the mixed-effect model, gave a good prediction of mean annual concentration measured using passive samplers on a continuous basis, at 8–10 reference sites in each study area (r2>0.85). Based on the modelled results, it appears that WHO and national air quality standards for NO2 will be routinely exceeded at a number of sites in each study area. Given the apparent stability of the pollution surface in each area, these `hotspots’ are also likely to be persistent over time, implying the potential for relatively high risks of chronic exposure in local populations. Overall the results indicate the capability to characterise spatial variation in traffic-related pollution in urban areas using a small number of intensive surveys, with low-cost sampling devices.

Excess cardiovascular mortality associated with cold spells in the Czech Republic

BackgroundThe association between cardiovascular mortality and winter cold spells was evaluated in the population of the Czech Republic over 21-yr period 1986–2006. No comprehensive study on cold-related mortality in central Europe has been carried out despite the fact that cold air invasions are more frequent and severe in this region than in western and southern Europe.MethodsCold spells were defined as periods of days on which air temperature does not exceed -3.5°C. Days on which mortality was affected by epidemics of influenza/acute respiratory infections were identified and omitted from the analysis. Excess cardiovascular mortality was determined after the long-term changes and the seasonal cycle in mortality had been removed. Excess mortality during and after cold spells was examined in individual age groups and genders.ResultsCold spells were associated with positive mean excess cardiovascular mortality in all age groups (25–59, 60–69, 70–79 and 80+ years) and in both men and women. The relative mortality effects were most pronounced and most direct in middle-aged men (25–59 years), which contrasts with majority of studies on cold-related mortality in other regions. The estimated excess mortality during the severe cold spells in January 1987 (+274 cardiovascular deaths) is comparable to that attributed to the most severe heat wave in this region in 1994.ConclusionThe results show that cold stress has a considerable impact on mortality in central Europe, representing a public health threat of an importance similar to heat waves. The elevated mortality risks in men aged 25–59 years may be related to occupational exposure of large numbers of men working outdoors in winter. Early warnings and preventive measures based on weather forecast and targeted on the susceptible parts of the population may help mitigate the effects of cold spells and save lives.

Parental smoking, socioeconomic factors, and risk of invasive meningococcal disease in children: a population based case-control study

AIMS To investigate the effects of parental smoking, socioeconomic characteristics, and indoor environment on the risk of invasive meningococcal disease in children. METHODS Population based case-control study. A total of 68 incident cases of invasive meningococcal disease in children less than 15 years old were compared with 135 controls selected from the same school and matched for year of birth, sex, and place of residence. Information on exposures was obtained in interviews with parents. RESULTS Invasive meningococcal disease was strongly associated with parental smoking; rate ratios adjusted for socioeconomic factors were 3.5 (95% confidence interval 1.4–8.7) for smoking of mother, 3.2 (1.5–6.9) for smoking of father, and 2.7 (1.3–5.4) for every 20 cigarettes smoked at home on an average day. The risk of the disease was strongly inversely related to maternal education and, less strongly, to ownership of a car and of a weekend house, fathers education, crowding, and the number of siblings, but these associations were reduced or eliminated in multivariate models. The type of heating and cooking (used as proxies for indoor air pollution) were not associated with the disease. CONCLUSION The risk of invasive meningococcal disease in children is strongly influenced by parental smoking and unfavourable socioeconomic circumstances.

Outdoor Air concentrations of nitrogen dioxide and sulfur dioxide and prevalence of wheezing in school children

We report analysis of data on outdoor air pollution and respiratory symptoms in children collected in the Czech part of the international Small Area Variations in Air pollution and Health (SAVIAH) Project, a methodological study designed to test the use of geographical information systems (GIS) in studies of environmental exposures and health at small area level. We collected the following data in two districts of Prague: (1) individual data on 3,680 children (response rate 88%) by questionnaires; (2) census-based socio-demographic data for small geographical units; (3) concentrations of nitrogen dioxide (NO2) and sulfur dioxide (SO2) measured by passive samplers in three 2-week surveys at 80 and 50 locations, respectively. We integrated all data into a geographical information system. Modeling of NO2 and SO2 allowed estimation of exposure to outdoor NO2 and SO2 at school and at home for each child. We examined the associations between air pollution and prevalence of wheezing or whistling in the chest in the last 12 months by logistic regression at individual level, weighted least squares regression at small area (ecological) level and multilevel modeling. The results varied by the level of analysis and method of exposure estimation. In multilevel analyses using individual data, odds ratios per 10 microg/m3 increase in concentrations were 1.16 (95% CI = 0.95-1.42) for NO2, and 1.08 (95% CI = 0.97-1.21) for SO2. While mapping of spatial distribution of NO2 and SO2 in the study area appeared valid, the interpolation from outdoor to personal exposures requires consideration.

SOCIOECONOMIC-FACTORS AND HEIGHT OF PRESCHOOL-CHILDREN IN THE CZECH-REPUBLIC

The effect of socioeconomic factors on growth was investigated among 2275 children 3 to 6 years old attending nurseries in the Czech Republic. Measured heights of children were converted into height-for-age z scores. After adjustment for birthweight, parental height, and other socioeconomic variables, only mothers education was independently and significantly associated with childrens height; adjusted differences in z scores between children of secondary- and university-educated mothers and children of mothers with only primary education were 0.12 and 0.31, respectively. This is equivalent to 0.5 and 1.5 cm, respectively, for children 5 years old.

Trends in cardiovascular mortality and hospitalisations, and potential contribution of inhospital case-fatality rates to changes in national mortality in the Czech Republic 1994–2009

Objectives To analyse trends in cardiovascular disease (CVD) mortality and hospitalisations in the Czech Republic in 1994–2009 and to assess the contribution of inhospital case-fatality rates (CFR) to changes in national CVD mortality. Design National hospitalisation and mortality registers were used to estimate rates of hospital admissions and mortality for hypertension, angina pectoris, acute myocardial infarction (AMI), chronic ischaemic heart disease chronic (IHD), heart failure and stroke. Patients All hospitalisations and deaths from CVD during 1994–2009. Main Outcome Measures Average annual relative changes in age-standardised mortality, hospital admission and inhospital CFR. Results Between 1994 and 2009, 5 409 407 hospital admissions and 930 659 deaths from CVD were recorded. The age-standardised CVD mortality rate fell from 561 to 357 per 100 000 population (mean annual decline 3.1%) but hospitalisation rates remained relatively stable, with 2800 admissions per 100 000 per year (annual decline 0.7%). Inhospital CFR decreased significantly in all examined diagnoses but most rapidly for AMI (by 5.5% per year) and stroke (4.2% per year). The improvements were larger in the younger population than in elderly persons. Calculations based on unlinked mortality and hospitalisation data suggest that a decline in inhospital CFR may explain approximately 24%, 41% and 61% of the decline in national deaths from IHD, AMI and stroke, respectively. Conclusions During the study period, the overall CVD hospitalisation rates remained high but inhospital CFR declined considerably. The improved case-fatality seems to have made a substantial contribution to the decline in the national CVD mortality, particularly for AMI and stroke.

Meningococcal Meningitis in CSR: A Preepidemic Situation?

Meningococcal meningitis has become a problem in many European countries, with epidemics occurring during the past 10-15 years. There have also been outbreaks in some non-European countries. The latest meningococcal meningitis epidemic recorded in the CSR (Czech Socialist Republic) occurred in 1953, with the morbidity reaching 14.8 per 100 000 population. After the mid 1950s there was a gradual decline in morbidity, the lowest value (0.3 per 100 000 population) being reached in 1974. Since 1975 there has been a continual rise in morbidity, the value notified for 1982 was 1.2 per 100 000 population. An analysis of the epidemiological situation in meningococcal meningitis in CSR for the past 30 years was performed. Different indicators of the onset of epidemics were evaluated. Shift in the age distribution of patients was found to be the most valuable sign of changing epidemiological situtation. An attempt was made to prognosticate mathematically its further development. The analysis of the epidemiological data suggests that CSR is in a preepidemic situation. This finding is all the more important because a change has been found in the serogroup and serotype patterns of Neisseria meningitidis strains isolated from cerebrospinal fluid.