Search PubMed⌕ Search

Biomedical subjects

J Pekkanen

Publications and source records attributed to J Pekkanen.

At least 19 recordsLinked to original sources
PubMed2003

Effects of fine and ultrafine particles on cardiorespiratory symptoms in elderly subjects with coronary heart disease: the ULTRA study.

The ULTRA Study, a study investigating the association between fine and ultrafine particulate air pollution and cardiorespiratory health, was conducted during the winter of 1998-1999 in Amsterdam, the Netherlands; Erfurt, Germany; and Helsinki, Finland. At each study center, a panel of elderly subjects with coronary heart disease recorded cardiac and respiratory symptoms in a diary. Exposure to ambient air pollution was characterized by measuring daily mass concentrations of particles smaller than 10 micro m (PM(10)) and 2.5 micro m (PM(2.5)), number concentrations of ultrafine particles (NC(0.01-0.1)), and gases. Odds ratios for the relation of symptoms to air pollution, adjusted for time trend, respiratory infections, and meteorologic variables, were mostly homogeneous across the centers. No association was found between air pollution and chest pain. A 10- micro g/m(3) increase in PM(2.5) was positively associated with the incidence of shortness of breath (odds ratio (OR) = 1.12, 95% confidence interval (CI): 1.02, 1.24) and with avoidance of activities (OR = 1.09, 95% CI: 0.97, 1.22). NC(0.01-0.1) was only associated with the prevalence of avoidance of activities (OR = 1.10, 95% CI: 1.01, 1.19). In conclusion, PM(2.5) was associated with some cardiac symptoms in three panels of elderly subjects. PM(2.5 )was more strongly related to cardiorespiratory symptoms than ultrafine particles were.

Aged↗
PubMed2003

Which factors explain the lower prevalence of atopy amongst farmers' children?

BACKGROUND: The inverse association between farming and atopy in children has been attributed to microbial exposure, especially through livestock. Very little is known about other potential explanatory factors. OBJECTIVE: To explore potential differences in lifestyle and environmental factors between farmer and non-farmer families, and whether these factors could explain the association between farming and childhood atopy. METHODS: A cross-sectional study, including 366 farmers' and 344 non-farmers' children in eastern Finland. Information regarding exposure and background characteristics was gathered by a written questionnaire. Atopy was defined as having one or more positive skin prick test reactions (> 3 mm) against the six common aeroallergens. RESULTS: Regardless of the current farming type, atopy was less frequent among the farmers' children than the non-farmers' children (aOR 0.56, 95% CI 0.40-0.78). Remarkable differences were seen in many lifestyle factors (including diet) between the farmer and non-farmer families, but only a few of the explored factors were associated with atopy. The frequency of current livestock contacts seemed to have an inverse, dose-dependent association with atopy (aOR 0.46, 95% CI 0.22-0.97 for daily vs. no contact). Having lived on a dairy farm in infancy (aOR 0.51, 95% CI 0.28-0.93), or having had cats or dogs in infancy (aOR 0.60, 95% CI 0.42-0.85), decreased the risk of atopy at school age. The inverse association between farming and atopy was not explained by the sociodemographic factors, or by differences in conventional risk factors of atopy. Animal contacts explained partially, but not completely, the association. CONCLUSION: Higher frequency of animal contacts is one factor, but probably not the only one, explaining the inverse association of farming and atopy in children. The importance of early life exposures may have recently been over-emphasized, and current exposures discounted, when studying the risk factors of childhood atopy.

Agriculture↗
PubMed2003

Pet- and pollen-induced upper airway symptoms in farmers and in nonfarmers.

The effect of farming on the risk of upper airway symptoms is not clear. In this cross-sectional, population-based study, 198 female farmers, 50 nonfarmers living on a farm, and 218 nonfarmers not living on a farm, filled in a symptom questionnaire and underwent skin-prick testing with common and agricultural allergens. In the logistic regression analysis, the latter group served as a control. Several adjustments were made, including childhood farming environment. Current farming was found to decrease the risks of pet- and pollen-induced upper airway symptoms, dose-dependently with the intensity and duration of animal husbandry. Including skin-test positivity to pets in the regression models did not affect the negative association between farming and pet-induced symptoms. In contrast, animal husbandry increased the risk of farm work-induced upper airway symptoms. Animal husbandry often induces work-related upper airway symptoms. However, the present study among female adults suggests that it may also decrease the risk of pet- and pollen-induced upper airway symptoms.

Agricultural Workers' Diseases↗
PubMed2002

Does heredity modify the association between farming and allergy in children?

AIM: It has been suggested that living on a farm decreases the risk of childhood allergy, especially if farming involves livestock. The aim of this study was to examine the association between farming and allergy in children, and the influence of atopic heredity in this association. METHODS: The cross-sectional data of the 7981 children aged 13-14 y who participated in the Finnish ISAAC study between the years 1994 and 1995 were used to evaluate the association between farming and allergy. RESULTS: Living on a farm was associated with a decreased risk of current symptoms of allergic rhinoconjunctivitis among all children (aOR 0.79; 95% CI 0.63, 0.99), and with a decreased risk of hay fever, especially among those children with a parental history of hayfever (aOR 0.60; 95% CI 0.40-0.89, p = 0.072 for interaction). The children of farmers with a history of hay fever also had a decreased risk of current wheeze (aOR 0.38; 95% CI 0.12-1.24, p = 0.040 for interaction). No significant association was found between farming and either asthma or eczema. Children living on a farm with livestock had the lowest risk of allergic rhinoconjunctivitis (aOR 0.69), followed by those living on a farm without livestock (aOR 0.89) compared with the non-farming children (p-value for trend 0.024). CONCLUSION: Our results support the recent findings on a decreased risk of allergy among the children living on farms. A possible differential effect of parental history of hay fever on the relation of farming environment and the risk of allergic symptoms warrant further investigation.

Adolescent↗
PubMed2002

Effects of air pollution on changes in lung function induced by exercise in children with chronic respiratory symptoms.

OBJECTIVE: To investigate how daily variations in ambient air pollution, especially in particles, during the cold of winter affect repeated measurements of baseline lung function and exercise induced bronchial responsiveness among primary school children with chronic respiratory symptoms. METHODS: During alternate school weeks (maximum five) from February to April 1994, 33 children took part in exercise challenge tests (n=141 tests). The exercise challenges were conducted outdoors in a school yard in the centre of Kuopio, Finland. Spirometric lung functions were measured indoors before the exercise, and 3 and 10 minutes after. Daily mean concentrations of PM(10), black smoke (BS), NO(2), CO, SO(2), and particle size and numbers were monitored at a nearby fixed monitoring site. RESULTS: Daily variations in ambient air pollution were not associated with enhanced bronchial responsiveness. However, increased concentrations of BS, PM(10), particle numbers, NO(2), and CO were consistently associated with an impairment of baseline lung functions. The reductions in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)) were 0.5% and 0.6%, respectively, for each 10 microg/m(3) increase in BS (lag 2). CONCLUSION: Particles derived from combustion affect baseline lung function rather than bronchial responsiveness among children with chronic respiratory symptoms.

Air Pollution↗
PubMed2002

In search of childhood asthma: questionnaire, tests of bronchial hyperresponsiveness, and clinical evaluation.

BACKGROUND: The definition or diagnosis of asthma is a challenge for both clinicians and epidemiologists. Symptom history is usually supplemented with tests of bronchial hyperresponsiveness (BHR) in spite of their uncertainty in improving diagnostic accuracy. METHODS: To assess the interrelationship between respiratory symptoms, BHR, and clinical diagnosis of asthma, the respiratory symptoms of 1633 schoolchildren were screened using a questionnaire (response rate 81.2%) and a clinical study was conducted in a subsample of 247 children. Data from a free running test and a methacholine inhalation challenge test were available in 218 children. The diagnosis of asthma was confirmed by a paediatric allergist. RESULTS: Despite their high specificity (>0.97), BHR tests did not significantly improve the diagnostic accuracy after the symptom history: area under the receiver operator characteristic (ROC) curve was 0.90 for a logistic regression model with four symptoms and 0.94 for the symptoms with free running test and methacholine inhalation challenge results. On the other hand, BHR tests had low sensitivity (0.35-0.47), whereas several symptoms had both high specificity (>0.97) and sensitivity (>0.7) in relation to clinical asthma, which makes them a better tool for asthma epidemiology than BHR. CONCLUSIONS: Symptom history still forms the basis for defining asthma in both clinical and epidemiological settings. BHR tests only marginally increased the diagnostic accuracy after symptom history had been taken into account. The diagnosis of childhood asthma should not therefore be overlooked in symptomatic cases with no objective evidence of BHR. Moreover, BHR should not be required for defining asthma in epidemiological studies.

Asthma↗
PubMed2002

Non-eosinophilic asthma: importance and possible mechanisms.

There is increasing evidence that inflammatory mechanisms other than eosinophilic inflammation may be involved in producing the final common pathway of enhanced bronchial reactivity and reversible airflow obstruction that characterises asthma. A review of the literature has shown that, at most, only 50% of asthma cases are attributable to eosinophilic airway inflammation. It is hypothesised that a major proportion of asthma is based on neutrophilic airway inflammation, possibly triggered by environmental exposure to bacterial endotoxin, particulate air pollution, and ozone, as well as viral infections. If there are indeed two (or more) subtypes of asthma, and if non-eosinophilic (neutrophil mediated) asthma is relatively common, this would have major consequences for the treatment and prevention of asthma since most treatment and prevention strategies are now almost entirely focused on allergic/eosinophilic asthma and allergen avoidance measures, respectively. It is therefore important to study the aetiology of asthma further, including the underlying inflammatory profiles.

Asthma↗
PubMed2001

Comparison of two-level and three-level classifications of moisture-damaged dwellings in relation to health effects.

A total of 630 randomly selected dwellings were surveyed for visible signs of moisture damage by civil engineers, and questionnaire responses were collected from the occupants (a total of 1,017 adults) to analyse the association between moisture damage and occupant health. A three-level grading system was developed, which took into account the number of damage sites in buildings and estimated the severity of the damage. In the present study, this grading system was tested as an improved model of moisture damage-related exposure in comparison to a conventional two-category system: based on independent, technical criteria it also allowed dose-response to be estimated. The questionnaire probed 28 individual health symptoms, based on earlier reported associations with building moisture and mould-related exposure. Criteria in evaluating the goodness of the selected exposure model were (1) dose-responsiveness and (2) higher risk compared to a two-level classification. Dose-responsiveness was observed with the three-level classification in 7, higher risk in 10, and both criteria in 5 out of 28 health symptoms. Two-level classification had higher risk in 4 health symptoms. Dose-dependent risk increases for respiratory infections and lower respiratory symptoms, and recurrent irritative and skin symptoms were observed with the three-level classification using symptom score variables. Although the results did not unambiguously support the three-level model, they underline the importance of developing more accurate exposure models in assessing the severity of moisture damage.

Adult↗
PubMed2001

Caesarean section and risk of asthma and allergy in adulthood.

This study evaluated the relationship of caesarean section to the risk of asthma in adulthood. The data were based on a prospective birth cohort born in northern Finland in 1966. In 1997, when the members of the cohort were 31 years old, information on current doctor-diagnosed asthma and other allergic disorders was obtained from 1953 subjects by a self-administered questionnaire and skin prick test. Caesarean section had a strong effect on current doctor-diagnosed asthma in adulthood with an adjusted odds ratio (OR) of 3.23 (95% CI 1.53, 6.80). However, no substantial effects were observed for atopy, hay fever, and atopic eczema.

Adult↗
PubMed2001

Confounding and effect modification in the short-term effects of ambient particles on total mortality: results from 29 European cities within the APHEA2 project.

We present the results of the Air Pollution and Health: A European Approach 2 (APHEA2) project on short-term effects of ambient particles on mortality with emphasis on effect modification. We used daily measurements for particulate matter less than 10 microm in aerodynamic diameter (PM10) and/or black smoke from 29 European cities. We considered confounding from other pollutants as well as meteorologic and chronologic variables. We investigated several variables describing the cities' pollution, climate, population, and geography as potential effect modifiers. For the individual city analysis, generalized additive models extending Poisson regression, using a smoother to control for seasonal patterns, were applied. To provide quantitative summaries of the results and explain remaining heterogeneity, we applied second-stage regression models. The estimated increase in the daily number of deaths for all ages for a 10 microg/m3 increase in daily PM10 or black smoke concentrations was 0.6% [95% confidence interval (CI) = 0.4-0.8%], whereas for the elderly it was slightly higher. We found important effect modification for several of the variables studied. Thus, in a city with low average NO2, the estimated increase in daily mortality for an increase of 10 microg/m3 in PM10 was 0.19 (95% CI = 0.00-0.41), whereas in a city with high average NO2 it was 0.80% (95% CI = 0.67-0.93%); in a relatively cold climate the corresponding effect was 0.29% (95% CI = 0.16-0.42), whereas in a warm climate it was 0.82% (95% CI = 0.69-0.96); in a city with low standardized mortality rate it was 0.80% (95% CI = 0.65-0.95%), and in one with a high rate it was 0.43% (95% CI = 0.24-0.62). Our results confirm those previously reported on the effects of ambient particles on mortality. Furthermore, they show that the heterogeneity found in the effect parameters among cities reflects real effect modification, which is explained by specific city characteristics.

Aged↗
PubMed2001

Small area estimation of incidence of cancer around a known source of exposure with fine resolution data.

OBJECTIVES: To describe the small area system developed in Finland. To illustrate the use of the system with analyses of incidence of lung cancer around an asbestos mine. To compare the performance of different spatial statistical models when applied to sparse data. METHODS: In the small area system, cancer and population data are available by sex, age, and socioeconomic status in adjacent "pixels", squares of size 0.5 km x 0.5 km. The study area was partitioned into sub-areas based on estimated exposure. The original data at the pixel level were used in a spatial random field model. For comparison, standardised incidence ratios were estimated, and full bayesian and empirical bayesian models were fitted to aggregated data. Incidence of lung cancer around a former asbestos mine was used as an illustration. RESULTS: The spatial random field model, which has been used in former small area studies, did not converge with present fine resolution data. The number of neighbouring pixels used in smoothing had to be enlarged, and informative distributions for hyperparameters were used to stabilise the unobserved random field. The ordered spatial random field model gave lower estimates than the Poisson model. When one of the three effects of area were fixed, the model gave similar estimates with a narrower interval than the Poisson model. CONCLUSIONS: The use of fine resolution data and socioeconomic status as a means of controlling for confounding related to lifestyle is useful when estimating risk of cancer around point sources. However, better statistical methods are needed for spatial modelling of fine resolution data.

Adolescent↗
PubMed2001

Ultrafine particles in urban air and respiratory health among adult asthmatics.

Airborne particles are associated with adverse health effects and contribute to excess mortality in epidemiological studies. A recent hypothesis proposes that the high numbers of ultrafine (<0.1 microm diameter) particles in ambient air might provoke alveolar inflammation and subsequently cause exacerbations in pre-existing cardiopulmonary diseases. To test the hypothesis adult asthmatics were followed with daily peak expiratory flow (PEF) measurements and symptom and medication diaries for six months, while simultaneously monitoring particulate pollution in ambient air. The associations between daily health endpoints of 57 asthmatics and indicators of air pollution were examined by multivariate regression models. Daily mean number concentration of particles, but not particle mass (PM10 (particle mass <10 microm), PM2.5-10, PM2.5, PM1), was negatively associated with daily PEF deviations. The strongest effects were seen for particles in the ultrafine range. However, the effect of ultrafine particles could not definitely be separated from other traffic generated pollutants, namely nitric oxide, nitrogen dioxide and carbon monoxide. No associations were observed with respiratory symptoms or medication use. Particle mass measurements can be strongly influenced by mechanically produced, soil-derived particles, which may not be associated with adverse health effects. Therefore, air quality monitoring should include particle number concentrations, which mainly reflect ultrafine particles.

Adult↗
PubMed2001

Environmental epidemiology: challenges and opportunities.

Epidemiology is struggling increasingly with problems with correlated exposures and small relative risks. As a consequence, some scholars have strongly emphasized molecular epidemiology, whereas others have argued for the importance of the population context and the reintegration of epidemiology into public health. Environmental epidemiology has several unique features that make these debates especially pertinent to it. The very large number of environmental exposures require prioritization, and the relative risks are usually very low. Furthermore, many environmental exposures can be addressed only by comparing populations rather than individuals, and the disruption of both local and global ecosystems requires us to develop new methods of study design. The population context is also very important to consider in risk management decisions because of the involuntary nature of most environmental exposures and the diversity of possible outcomes, both health- and nonhealth-related. Studies at the individual or molecular level tend to focus the research hypotheses and subsequent interventions at that level, even when research and interventions at other levels may be more appropriate. Thus, only by starting from the population and ecosystem levels can we ensure that these are given appropriate consideration. Although better research is needed at all levels, it is crucially important to choose the most appropriate level, or levels, of research for a particular problem. Only by conducting research at all these levels and by developing further methods to combine evidence from these different levels can we hope to address the challenges facing environmental epidemiology today.

Ecosystem↗
PubMed2001

Number concentration and size of particles in urban air: effects on spirometric lung function in adult asthmatic subjects.

Daily variations in ambient particulate air pollution are associated with variations in respiratory lung function. It has been suggested that the effects of particulate matter may be due to particles in the ultrafine (0.01-0.1 microm) size range. Because previous studies on ultrafine particles only used self-monitored peak expiratory flow rate (PEFR), we assessed the associations between particle mass and number concentrations in several size ranges measured at a central site and measured (biweekly) spirometric lung function among a group of 54 adult asthmatics (n = 495 measurements). We also compared results to daily morning, afternoon, and evening PEFR measurements done at home (n = 7,672-8,110 measurements). The median (maximum) 24 hr number concentrations were 14,500/cm(3) (46,500/cm(3)) ultrafine particles and 800/cm(3) (2,800/cm(3)) accumulation mode (0.1-1 microm) particles. The median (maximum) mass concentration of PM(2.5) (particulate matter < 2.5 microm) and PM(10) (particulate matter < 10 microm in aerodynamic diameter) were 8.4 microg/m(3) (38.3 microg/m(3)) and 13.5 microg/m(3) (73.7 microg/m(3)), respectively. The number of accumulation mode particles was consistently inversely associated with PEFR in spirometry. Inverse, but nonsignificant, associations were observed with ultrafine particles, and no associations were observed with large particles (PM(10)). Compared to the effect estimates for self-monitored PEFR, the effect estimates for spirometric PEFR tended to be larger. The standard errors were also larger, probably due to the lower number of spirometric measurements. The present results support the need to monitor the particle number and size distributions in urban air in addition to mass.

Adult↗
PubMed2001

Gestational age and occurrence of atopy at age 31--a prospective birth cohort study in Finland.

BACKGROUND: It has been suggested that main risk factors for development of allergic diseases operate already during pregnancy and in early childhood. OBJECTIVE: To study the association between gestational age, birth weight, parity and parental farming with the risk of atopy and asthma in young adults. METHODS: In a prospective birth cohort study, 5192 subjects born in Northern Finland in 1966 were followed up at the age of 31. Skin prick tests were done to three of the most common allergens in Finland and to house dust mite. Data on doctor-diagnosed asthma was obtained from questionnaires. Perinatal data had already been collected during pregnancy. RESULTS: The risk of atopy increased linearly with increasing length of pregnancy among babies born in the 35th weak of gestation or later. Gestational age equal to, or over 40 weeks compared with less than 36 weeks was associated with an increased risk of atopy (multivariate odds ratio 1.65, 95% CI 1.16, 2.34). The association was stronger among farmers' children (P for interaction 0.01). High parity and being a farmer's child (multivariate odds ratio 0.50, 95% CI 0.42-0.60) was associated with decreased risk of atopy. In contrast, no associations were observed for doctor-diagnosed asthma. CONCLUSIONS: The results underline the importance of pregnancy and very early childhood in the development of atopy, and suggest that timing of the environmental exposure is of importance for the immune system. No association was observed for asthma, which may be due to the multifactorial origins of asthma.

Adult↗