A foodborne outbreak due to Cryptosporidium parvum in Helsinki, November 2008.

We report the first foodborne outbreak caused by Cryptosporidium parvum in Finland. The outbreak occurred among personnel of the Public Works Department in Helsinki, who had eaten in the same canteen. 72 persons fell ill with diarrhoea, none was hospitalised. Four faecal samples obtained from 12 ill persons were positive for Cryptosporidium by an antigen identification assay and microscopy. The vehicle of infection could not be identified with certainty but a salad mixture was suspected.

Campylobacter enteritis in 188 hospitalized patients.

The clinical picture and epidemiologic characteristics of infection due to Campylobacter fetus subspecies jejuni were studied in 188 patients hospitalized in Finland during a three-year period. All but two patients had diarrhea; 90% had abdominal pain, fever, and fatigue; half had vomiting and headache; one third experienced electrolyte disturbances; and one fifth of the patients had other complications, most commonly pancreatitis (6%) and arthritis (5%). All age groups were affected, most usually those who were 0 to 9 years old and 20 to 29 years old. The incidence of domestic cases increased during the summer months. With only three exceptions (1.3%), all jejuni strains were sensitive to erythromycin. Among Finns who visited ten popular tourist countries, the incidence of hospitalized C jejuni enteritis cases varied from 0 to 63 per 100,000 travelers.

Increased incidence of cancer and asthma in houses built on a former dump area.

Twelve blockhouses were built in Helsinki in the 1970s on a former dump area containing industrial and household waste. We investigated whether the exposure to landfill caused cancer or other chronic diseases in the inhabitants of these houses. From the Population Register, we identified 2,000 persons who had ever lived in houses built on the dump area and a similar reference cohort from similar houses elsewhere in Helsinki. We identified their cancer cases from the Cancer Registry, and the other chronic diseases eligible for free medication from the Finnish Social Insurance Institution. At the end of 1998, 88 cases of cancer had been diagnosed, whereas the expected number based on the incidence rates among all inhabitants of Helsinki was 76.1. The excess cases were entirely attributable to males and to follow-up >or= 5 years after moving into the dump area [standardized incidence ratio (SIR) in this category, 1.61; 95% confidence interval (CI), 1.11-2.24], and they were distributed evenly over primary sites. The relative risk increased slightly with the number of years lived in the area. The relative risk of cancer between the dump area and reference houses was 1.50 (1.08-2.09), similar in both sexes. Of the other chronic diseases, the SIRs for asthma (1.63; CI, 1.27-2.07) and chronic pancreatitis (19.3; CI, 2.34-69.7) were significantly increased. The possibility of a causal association between dump exposure and incidence of cancer and asthma cannot be fully excluded. The Helsinki City Council decided to demolish the houses in the dump area, and most houses have already been destroyed.

Asthma and ambient air pollution in Helsinki.

OBJECTIVE: To study whether ambient air levels of sulphur dioxide (SO2), nitrogen dioxide (NO2), total suspended particulates (TSP), and ozone (O3) affect the number of hospital admissions for asthma. DESIGN: The associations between the daily number of admissions and air pollutants were analysed with Poisson regression, taking into account potential confounding factors by using the standardised protocol of the APHEA project. SETTING: Helsinki, Finland, 1987-89. PATIENTS AND MEASUREMENTS: Patients admitted to hospitals through emergency rooms because of asthma (n = 2421). The daily mean concentration was 13-25 micrograms/m3 for SO2, 33-41 micrograms/m3 for NO2, 19-41 micrograms/m3 for O3, and 58-109 micrograms/m3 for TSP during the different seasons. Values are means for various stations. The daily mean temperature during the three year period was +5.4 degrees C (range -37-27 degrees C). MAIN RESULTS: Positive associations with admissions were observed for O3 levels in all children under 14 years, and for SO2 levels in 15-64 year olds and among those older than 64. Significant associations were also seen between admissions for digestive tract diseases (the control) and O3 levels. This suggests that the modelling, which proved to be problematic, was unsatisfactory, or it may be a statistical coincidence. A rise in temperature was associated with a low number of admissions for asthma among 0-14 year olds and among 15-64 year olds, whereas humidity did not have a significant effect on the number of admissions. CONCLUSIONS: It is possible than even low level pollution may increase hospital admissions for asthma. However, definitive conclusions will be justified only after meta-analysis comprising several studies. The methodology was seen to have a strong effect on the results and standardised methods, possibly differing from those for the study concerning mortality, are needed to investigate the association between morbidity and ambient air pollutants.

Short term effects of air pollution on health: a European approach using epidemiologic time series data: the APHEA protocol.

BACKGROUND AND OBJECTIVES: Results from several studies over the past five years have shown that the current levels of pollutants in Europe and North America have adverse short term effects on health. The APHEA project aims to quantifying these in Europe, using standardised methodology. The project protocol and analytical methodology are presented here. DESIGN: Daily time series data were gathered for several air pollutants (sulphur dioxide; particulate matter, measured as total particles or as the particle fraction with an aerodynamic diameter smaller than a certain cut off, or as black smoke; nitrogen dioxide; and ozone) and health outcomes (the total and cause specific number of deaths and emergency hospital admissions). The data included fulfilled the quality criteria set by the APHEA protocol. SETTING: Fifteen European cities from 10 different countries with a total population over 25 million. METHODOLOGY: The APHEA collaborative group decided on a specific methodological procedure to control for confounding effects and evaluate the hypothesis. At the same time there was sufficient flexibility to allow local characteristics to be taken into account. The procedure included modelling of all potential confounding factors (that is, seasonal and long term patterns, meteorological factors, day of the week, holidays, and other unusual events), choosing the "best" air pollution models, and applying diagnostic tools to check the adequacy of the models. The final analysis used autoregressive Poisson models allowing for overdispersion. Effects were reported as relative risks contrasting defined increases in the corresponding pollutant levels. Each participating group applied the analyses to their own data. CONCLUSIONS: This methodology enabled results from many different European settings to be considered collectively. It represented the best available compromise between feasibility, comparability, and local adaptibility when using aggregated time series data not originally collected for the purpose of epidemiological studies.

Methodological issues in studies of air pollution and daily counts of deaths or hospital admissions.

STUDY OBJECTIVE: To review the issues and methodologies in epidemiologic time series studies of daily counts of mortality and hospital admissions and illustrate some of the methodologies. DESIGN: This is a review paper with an example drawn from hospital admissions of the elderly in Cleveland, Ohio, USA. MAIN RESULTS: The central issue is control for seasonality. Both over and under control are possible, and the use of diagnostics, including plots, is necessary. Weather dependence is probably non-linear, and adequate methods are necessary to adjust for this. In Cleveland, the use of categorical variables for weather and sinusoidal terms for filtering season are illustrated. After control for season, weather, and day of the week effects, hospital admission of persons aged 65 and older in Cleveland for respiratory illness was associated with ozone (RR = 1.09, 95% CI 1.02, 1.16) and particulates (PM10 (RR = 1.12, 95% CI 1.01, 1.24), and marginally associated with sulphur dioxide (SO2) (RR = 1.03, 95% CI = 0.99, 1.06). All of the relative risks are for a 100 micrograms/m3 increase in the pollutant. CONCLUSIONS: Several adequate methods exist to control for weather and seasonality while examining the associations between air pollution and daily counts of mortality and morbidity. In each case, care and judgement are required.

Microbiological quality in Finnish public swimming pools and whirlpools with special reference to free living amoebae: a risk factor for contact lens wearers?

To assess the possible risk of microbial keratitis associated with swimming or bathing in public pools, the microbiological quality as well as the presence of free living amoebae in 16 halogenated swimming pools and whirlpools, located in Helsinki, Finland, was determined. Five additional whirlpools situated in the ferries cruising from Finland to Sweden were included in the study. Other parameters investigated were the total bacterial count, identification of Pseudomonas aeruginosa and Staphylococcus aureus, measurement of free residual and combined chlorine, potassium permanganate index, urine, pH, and turbidity. Amoebae were detected in 41% of the pool water samples studied. Seven of 11 whirlpools and four of 10 swimming pools were shown to contain amoebae. An Acanthamoeba species was isolated from only one outdoor swimming pool; the other amoebae belonged to the genera Vexillifera, Flabellula, Hartmannella, and Rugipes. Although not a single verified case of Acanthamoeba keratitis has been found in Finland, the findings show that there is a theoretical risk of amoebic and bacterial keratitis associated with swimming or bathing in properly cleaned public pools. Consequently, we do not recommend swimming or bathing with contact lenses.

Lead in the ambient air and blood of children in Helsinki.

Lead concentrations have been measured in the ambient air of Helsinki since 1978. The mean air concentrations at various stations reached maximum values in 1980 of 333-1150 ng/m3. From 1980 to 1996 the concentrations decreased to one-hundredth, from 745 to 7 ng/m3, at the two centrally situated stations where measurements were made continuously. Concomitantly, the estimated annual emissions of lead in Helsinki decreased from 78 tons to < 1 ton, mainly owing to the cessation of lead emissions in exhaust gases from road traffic. The reduction in lead levels in the ambient air has been reflected by the lead levels in the blood of children in a centrally situated day-care centre. The mean concentration of lead in the blood of children in the day-care centre was 46 micrograms/l in 1983, 30 micrograms/l in 1988 and 26 micrograms/l in 1996.

Insensitivity of the routine dimethylglyoxime test for detecting release of nickel from earrings.

The Helsinki City Centre of the Environment tested two methods, dimethylglyoxime (DMG) and atomic absorption spectrometry (AAS), for detecting nickel release in piercing earrings. The DMG screening test was performed in two slightly different ways, with and without ethanol and heat prehandling. All 30 pairs of earrings tested, totalling 66 objects, were negative. However, according to our AAS test, 25 of the 66 objects (38%) released > or = 0.05% of nickel, the mean amount being 2.1% and the maximum 12%. When measured by AAS after artificial sweat treatment, 11 objects released more than 0.5 microgram/cm2 per week of nickel, the mean amount being 3.4 micrograms/cm2 and the range < 0.1-84 micrograms/cm2. After this sweat treatment, nine of the objects (14%) were positive in DMG tests. These findings indicate that the DMG test is unreliable for detecting nickel release from jewelry. Quality control of consumer items should be performed by laboratories that have quantitative analysis methods for such investigations.

Lead in the ambient air and blood specimens of children in Helsinki.

Ambient air lead concentrations have been measured in Helsinki since 1978. The mean concentrations at various stations reached maximum values in 1980, being then 209-1150 ng/m3. From 1980 to 1991 the concentrations decreased to one-eighth (335-41 ng/m3) at the three stations where measurements were made continuously. Concomitantly the estimated annual lead emissions in Helsinki decreased from 78 to 9 tons, mainly owing to the reduced emissions of lead in exhaust gases from road traffic. The mean concentration of lead in the blood of children in day-care centres was 46 micrograms/l in 1983 and 30 micrograms/l 5 years later. Similar concentrations were found in blood samples from a day-care centre beside a street with heavy traffic and in those from an area with less traffic.

Outbreak oof calicivirus gastroenteritis associated with eating frozen raspberries.

Small round structured viruses (SRSVs - for example, calici-, astro-, and entero-viruses) are the commonest causes of outbreaks of non-bacterial gastroenteritis worldwide. Transmission of SRSVs by water and by various foods - including salads, bakery prod

Asthma and low level air pollution in Helsinki.

The effects of relatively low levels of air pollution and weather conditions on the number of patients who had asthma attacks and who were admitted to a hospital were studied in Helsinki during a 3-y period. The number of admissions increased during cold weather (n = 4,209), especially among persons who were of working age but not among children. Even after standardization for temperature, all admissions, including emergency ward admissions, were significantly correlated with ambient air concentrations of nitrogen dioxide (NO2), nitric oxide (NO), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), and total suspended particulates (TSP). Regression analysis revealed that NO and O3 were most strongly associated with asthma problems. Effects of air pollutants and cold were maximal if they occurred on the same day, except for O3, which had a more pronounced effect after a 1-d lag. The associations between pollutants, low temperature, and admissions were most significant among adults of working age, followed by the elderly. Among children, only O3 and NO were significantly correlated with admissions. Levels of pollutants were fairly low, the long-term mean being 19.2 micrograms/m3 for SO2, 38.6 micrograms/m3 for NO2, 22.0 micrograms/m3 or O3, and 1.3 mg/m3 for CO. In contrast, the mean concentration of TSP was high (76.3 micrograms/m3), and the mean temperature was low (+ 4.7 degrees C). These results suggest that concentrations of pollutants lower than those given as guidelines in many countries may increase the incidence of asthma attacks.

Mortality and air pollution in Helsinki.

In Helsinki, Finland, from 1987 to 1993, the authors studied the associations between daily concentrations of sulphur dioxide, nitrogen dioxide, ozone, total suspended particulates, and particulates with aerodynamic diameters less than 10 microm (PM10), and the daily number of deaths from all causes and from cardiovascular causes. Investigators used Poisson regressions to conduct analyses in two age groups, and they controlled for temperature, relative humidity, day of the week, month, year, long-term trend, holidays, and influenza epidemics. The PM10 levels were associated significantly with all-cause and cardiovascular mortality among persons under the age of 65 y of age. In the less-than-65-y age group, sulfur dioxide and ozone were also associated significantly with cardiovascular mortality. The effect of ozone was independent of the PM10 effect, whereas sulfur dioxide became nonsignificant when modeled with PM10. An increase of 10 microg/m3 in PM10 resulted in increases in total mortality and cardiovascular mortality of 3.5% (95% confidence interval=1.0, 5.8) and 4.1% (95% confidence interval=0.4, 10.3), respectively. A 20 microg/m3 increase in ozone was associated with a 9.9% (95% confidence interval=1.1, 19.5) increase in cardiovascular mortality; however, ozone results were inconsistent. Moreover, in addition to their separate effects, high concentrations of PM10, ozone, and nitrogen dioxide had a further harmful additive effect. Typically, PM10 was a better indicator of particulate pollution than total suspended particulates. The authors' findings suggest that (a) even low levels of particulates are related to an increase in cardiovascular mortality; (b) ozone--even in low concentrations--is associated, independently, with cardiovascular mortality; and (c) PM10, ozone, and nitrogen dioxide--the essential components of summertime pollution--have harmful interactions at high concentrations.

Short-term effects of air pollution on hospital admissions of respiratory diseases in Europe: a quantitative summary of APHEA study results. Air Pollution and Health: a European Approach.

The Air Pollution and Health: a European Approach (APHEA) project is a coordinated study of the short-term effects of air pollution on mortality and hospital admissions. Five West European cities (i.e., London, Amsterdam, Rotterdam, Paris, Milano) contributed several years of hospital admissions data for all respiratory causes. In the current study, the authors describe the results obtained from the quantitative pooling (meta-analysis) of local analyses. The diagnostic group was defined by ICD 460-519. The age groups studied were 15-64 y (i.e., adults) and 65+ y (elderly). The air pollutants studied were sulfur dioxide; particles (i.e., Black Smoke or total suspended particles); ozone; and nitrogen dioxide. The pollutants were obtained from existing fixed-site monitors in a standardized manner. We used Poisson models and standardized confounder models to examine the associations between daily hospital admissions and air pollution. We conducted quantitative pooling by calculating the weighted means of local regression coefficients. We used a fixed-effects model when no heterogeneity could be detected; otherwise, we used a random-effects model. When possible, the authors investigated the factors correlated with heterogeneity. The most consistent and strong finding was a significant increase of daily admissions for respiratory diseases (adults and elderly) with elevated levels of ozone. This finding was stronger in the elderly, had a rather immediate effect (same or next day), and was homogeneous over cities. The elderly were affected more during the warm season. The Sulfur dioxide daily mean was available in all cities, and it was not associated consistently with an adverse effect. Effects were present in areas in which more than one station was used in the assessment of daily exposure. Some significant associations were observed, although no conclusion that related to an overall particle effect could be drawn. The effect of Black Smoke was significantly stronger with high nitrogen dioxide levels on the same day, but nitrogen dioxide itself was not associated with admissions. The ozone results were in good agreement with the results of similar U.S. studies. The coherence of the results of this study and other results gained under different conditions strengthens the argument for causality.

Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomised trial.

OBJECTIVE: To examine whether long term consumption of a probiotic milk could reduce gastrointestinal and respiratory infections in children in day care centres. DESIGN: Randomised, double blind, placebo controlled study over seven months. SETTING: 18 day care centres in Helsinki, Finland. PARTICIPANTS: 571 healthy children aged 1-6 years: 282 (mean (SD) age 4.6 (1.5) years) in the intervention group and 289 (mean (SD) age 4.4 (1.5) years) in the control group. INTERVENTION: Milk with or without Lactobacillus GG. Average daily consumption of milk in both groups was 260 ml. MAIN OUTCOME MEASURES: Number of days with respiratory and gastrointestinal symptoms, absences from day care because of illness, respiratory tract infections diagnosed by a doctor, and course of antibiotics. RESULTS: Children in the Lactobacillus group had fewer days of absence from day care because of illness (4.9 (95% confidence interval 4.4 to 5.5) v 5.8 (5.3 to 6.4) days, 16% difference, P=0.03; age adjusted 5.1 (4.6 to 5.6) v 5.7 (5.2 to 6.3) days, 11% difference, P=0.09). There was also a relative reduction of 17% in the number of children suffering from respiratory infections with complications and lower respiratory tract infections (unadjusted absolute % reduction -8.6 (-17.2 to -0.1), P=0.05; age adjusted odds ratio 0.75 (0.52 to 1.09), P=0.13) and a 19% relative reduction in antibiotic treatments for respiratory infection (unadjusted absolute % reduction -9.6 (-18.2 to -1.0), P=0.03; adjusted odds ratio 0.72 (0.50 to 1.03), P=0.08) in the Lactobacillus group. CONCLUSIONS: Lactobacillus GG may reduce respiratory infections and their severity among children in day care. The effects of the probiotic Lactobacillus GG were modest but consistently in the same direction.

Short-term effects of ambient sulphur dioxide and particulate matter on mortality in 12 European cities: results from time series data from the APHEA project. Air Pollution and Health: a European Approach.

OBJECTIVES: To carry out a prospective combined quantitative analysis of the associations between all cause mortality and ambient particulate matter and sulphur dioxide. DESIGN: Analysis of time series data on daily number of deaths from all causes and concentrations of sulphur dioxide and particulate matter (measured as black smoke or particles smaller than 10 microns in diameter (PM10)) and potential confounders. SETTING: 12 European cities in the APHEA project (Air Pollution and Health: a European Approach). MAIN OUTCOME MEASURE: Relative risk of death. RESULTS: In western European cities it was found that an increase of 50 micrograms/m3 in sulphur dioxide or black smoke was associated with a 3% (95% confidence interval 2% to 4%) increase in daily mortality and the corresponding figure for PM10 was 2% (1% to 3%). In central eastern European cities the increase in mortality associated with a 50 micrograms/m3 change in sulphur dioxide was 0.8% (-0.1% to 2.4%) and in black smoke 0.6% (0.1% to 1.1%). Cumulative effects of prolonged (two to four days) exposure to air pollutants resulted in estimates comparable with the one day effects. The effects of both pollutants were stronger during the summer and were mutually independent. CONCLUSIONS: The internal consistency of the results in western European cities with wide differences in climate and environmental conditions suggest that these associations may be causal. The long term health impact of these effects is uncertain, but today's relatively low levels of sulphur dioxide and particles still have detectable short term effects on health and further reductions in air pollution are advisable.