Role of bronchial responsiveness testing in asthma prevalence surveys.
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Asthma↗
Biomedical subjects
J Pekkanen
Publications and source records attributed to J Pekkanen.
Maternal age at menarche and atopy among offspring at the age of 31 years.
BACKGROUND: Influences of female hormones on the occurrence of allergic disorders have been suggested. Age at menarche may be a marker of endogenous oestrogen levels. Data from a Finnish birth cohort followed to adulthood were analysed to determine whether there is any association between maternal age at menarche and the occurrence of atopy among offspring. METHODS: The study was conducted in 5188 subjects born in northern Finland for whom data collections were started during pregnancy and a follow up examination was completed at the age of 31 years. Atopy was determined by skin prick tests with cat, birch, grass, and mite extracts, and doctor diagnosed asthma was ascertained by questionnaire at follow up. Maternal age at menarche was obtained from perinatal data. Logistic regression models were used to adjust for maternal age, parity, smoking, season of birth, parental allergy, and measures of adiposity and socioeconomic status. RESULTS: The prevalence of atopy at the age of 31 years was lower in children whose mothers reached menarche at a later age, especially after age 15. Compared with children whose mothers started menarche at the age of 16 or over, the adjusted odds ratios of being atopic for children whose mothers started menarche younger than or at 12, 13, 14 and 15 years were 1.43 (95% CI 1.12 to 1.83), 1.29 (95% CI 1.03 to 1.60), 1. 15 (95% CI 0.93 to 1.42), and 1.19 (95% CI 0.95 to 1.48), respectively. Among girls, the offspring's own age at menarche was not significantly associated with atopy. CONCLUSION: Our results encourage further evaluation of the potential effect of maternal age at menarche on the later development of atopy and possible biological mechanisms.
Adolescent↗
Respiratory effects of environmental tobacco smoke in a panel study of asthmatic and symptomatic children.
The effect of environmental tobacco smoke (ETS) on respiratory health was investigated among 7- to 12-yr-old children with asthmatic (n = 74) or cough (n = 95) symptoms. For 3 mo the children measured their peak expiratory flow rate (PEFR) every morning and evening, and kept a daily diary of respiratory symptoms. They also noted daily whether they had used respiratory medication and whether someone had smoked inside their home. Eleven percent of the asthmatic children and 14% of the children with cough had exposure to ETS at home during the study. In multiple regression and analyses controlling for potential confounders, any exposure to ETS during the study was associated with a reduction of 42 L/min (95% confidence interval [CI]: 10 to 74 L/min) in morning and 41 L/min (95% CI: 8 to 74 L/min) in evening PEFR among asthmatic children. Among these children, a dose-dependent increase in the effect of ETS was also seen. Daily variation in ETS exposure was only weakly (-9.2 L/min; 95% CI: 2.9 to 21.2 L/min) associated with PEFR, but the previous day's ETS exposure was a risk factor for bronchodilator use (relative risk [RR]: 10.3; 95% CI: 1.3 to 83.7), as well as for cough (RR: 12.4; 95% CI: 2.4 to 63.3) and phlegm production (RR: 7. 8; 95% CI: 1.4 to 41.7), on any given day. Among children with cough only, there was only a weak suggestion of any possible ETS effect. In conclusion, we found that exposure to ETS was associated with a decline in peak flow and increases in respiratory symptoms and use of bronchodilator drugs among asthmatic children.
Asthma↗
Obstetric complications and asthma in childhood.
Studies have shown that perinatal factors are associated with childhood asthma. The current analyses examined the association between obstetric complications and risk of asthma at the age of 7 years using a prospectively population-based birth cohort in northern Finland. Results indicated that obstetric complications were associated with a higher risk of asthma among children. Those children who were administered special procedures at birth, i.e., cesarean section, vacuum extraction, and other procedures, including use of forceps, manual auxiliary, and extraction breech, had an adjusted odds ratio (OR) for asthma of 1.38 (95% confidence interval [CI] 1.00-1.92), 1.32 (95% CI 0.80-2.19), and 2.14 (95% CI 1.06-4.33), respectively, as compared to children who were delivered normally. Children who had a lower Apgar score at the first and the fifth minute after birth also had a higher risk as compared to those who had an Apgar score of 9-10. The results encourage further evaluation of the association between obstetric complications and risk of asthma among children in other populations, and further exploration of possible mechanisms underlying the association.
Adult↗
Exposure to natural fluoride in well water and hip fracture: a cohort analysis in Finland.
In the retrospective cohort study based on record linkage, the authors studied a cohort of persons born in 1900-1930 (n = 144,627), who had lived in the same rural location at least from 1967 to 1980. Estimates for fluoride concentrations (median, 0.1 mg/liter; maximum, 2.4 mg/liter) in well water in each member of the cohort were obtained by a weighted median smoothing method based on ground water measurements. Information on hip fractures was obtained from the Hospital Discharge Registry for 1981-1994. No association was observed between hip fractures and estimated fluoride concentration in the well water in either men or women when all age groups were analyzed together. However, the association was modified by age and sex so that among younger women, those aged 50-64 years, higher fluoride levels increased the risk of hip fractures. Among older men and women and younger men, no consistent association was seen. The adjusted rate ratio was 2.09 (95% confidence interval: 1.16, 3.76) for younger women who were the most exposed (>1.5 mg/liter) when compared with those who were the least exposed (< or =0.1 mg/liter). The results suggest that fluoride increases the risk of hip fractures only among women.
Aged↗
Age of entry to nursery and allergies in later life.
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Adolescent↗
Prenatal factors and occurrence of rhinitis and eczema among offspring.
BACKGROUND: It has recently been suggested that an atopic phenotype may already be programmed in utero. We examine here the association between prenatal factors and the subsequent development of allergic rhinitis and eczema among offspring. METHODS: The analyses were based on 8088 children in a population-based prospective birth cohort started in northern Finland in 1985-6. RESULTS: The prevalences of allergic rhinitis and allergic eczema by the age of 7 years among 8088 children were 3.3% and 6.7%, respectively. The results indicate that low parity, febrile infections in pregnancy, and the use of contraceptives before pregnancy increased the risk of allergic disorders among children. Bleeding in the first trimester and a greater weight gain during pregnancy appeared to be risk factors for rhinitis only. Children whose mothers experienced infections in the first trimester had ORs of 2.65 (95% CI 1.50-4.69) for rhinitis and 1.63 (95% CI 1.00-2.69) for eczema after adjustment for potential confounders. CONCLUSIONS: Obstetric complications and infection in pregnancy may increase the risk of allergic disorders among the offspring.
Adult↗
Fine particulate air pollution, resuspended road dust and respiratory health among symptomatic children.
The short-term association of particulate air pollution with peak expiratory flow rate (PEF) and respiratory symptoms was examined. Forty-nine children with chronic respiratory symptoms aged 8-13 yrs were followed daily for six weeks in spring, 1995, in Kuopio, Finland. Daily concentrations of particulate material with a 50% cut-off aerodynamic diameter < or = 10 microm and < or = 2.5 microm (PM10 and PM2.5, respectively), black carbon, and the number concentrations of particles from 0.01-10 microm diameter were measured. During the study period, PM10 were mainly resuspended soil and street dust, and the concentration was estimated using aluminum content of PM10 samples. No consistent effect of particles was found as the associations varied by lag. Of the lags examined, only 1-day lagged PM2.5 was statistically significantly associated with morning PEF (beta=-1.06, SE=0.52 (per interquartile increase in pollutant)). Evening PEF was significantly associated with the 1-day lagged number of particles in the size range 0.1-1.0 microm (beta=-1.56, SE=0.72). One-day lagged PM10, PM2.5-10, PM2.5 and resuspended PM10, and 4-day average of PM2.5 were significantly associated with increased risk of cough. Given the short duration of the study, separating the effects of different types of particles was difficult. The present study demonstrates the highly variable size and number distribution and chemical composition of particles in Finland, and underlines the importance of measuring the size and chemical composition of particles to determine which types of particles are associated with health effects.
Adolescent↗
Personally measured weekly exposure to NO2 and respiratory health among preschool children.
Nitrogen dioxide is known as a deep lung irritant. The aim of this study was to find out whether the relatively low ambient air NO2 concentrations in the northern city of Helsinki had an impact on the respiratory health of children. The association between personal exposure to ambient air NO2 and respiratory health was investigated in a 13-week follow-up study among 163 preschool children aged 3-6 yrs. Personal weekly average exposure to NO2 was measured by passive diffusion samplers attached to the outer garments. Symptoms were recorded daily in a diary by the parents. Among 53 children, peak expiratory flow (PEF) was measured at home in the mornings and evenings. The association between NO2 exposure and respiratory symptoms was examined with Poisson regression. The median personal NO2 exposure was 21.1 microg x m(-3) (range 4-99 microg x m(-3)). An increased risk of cough was associated with increasing NO2 exposure (risk ratio = 1.52; 95% confidence interval 1.00-2.31). There was no such association between personal weekly NO2 exposure and nasal symptoms, but a nonsignificant negative association was found between the exposure and the weekly average deviation in PEF. In conclusion, even low ambient air NO2 concentrations can increase the risk of respiratory symptoms among preschool children.
Child↗
Defining asthma in epidemiological studies.
It has been suggested that, in epidemiological studies, asthma should be defined as symptomatic bronchial hyperresponsiveness (BHR). This paper critically examines the validity of this and alternative methods of defining asthma by reviewing population-based studies validating BHR and symptom questionnaires against asthma defined on the basis of a clinical assessment. It is emphasized that a single definition of asthma will not be applicable to all studies. When the aim of a study is to compare differences in prevalence of asthma between populations, Youden's Index (sensitivity + specificity - 1) is the best single measure of validity. BHR has similar or better specificity, but much worse sensitivity, and therefore a worse Youden's Index, than symptom questionnaires. When the aim is to estimate relative risks, the validity of the definition of asthma depends more on its positive predictive value. Therefore, more specific methods of detecting asthmatics, such as severe symptoms, diagnoses of asthma, or symptomatic BHR may be most useful in cohort and case-control studies. In contrast, conversely, the method of choice for the first phase of prevalence comparisons is standardized written or video symptom questionnaires. In order to explore reasons for the differences in asthma prevalence, and to estimate possible differential symptom reporting, questionnaires can be supplemented with bronchial hyperresponsiveness and other testing in subsamples of the symptomatic and nonsymptomatic subjects. However, symptoms and bronchial hyperresponsiveness should usually be analysed separately rather than combined due to the poor agreement between bronchial hyperresponsiveness and clinical asthma.
Asthma↗
Infections in early childhood and risk of atopic disease.
Having more siblings has been shown to be associated with lower risk of atopic diseases. This might be due to the higher number of infections in larger families. Because children attending day care centres have more respiratory infections, we analysed the association of number of siblings and day care attendance in children aged 1-3 y with atopic disease in a cross sectional survey of 8387 schoolchildren aged 13-14 y and their parents in four regions of Finland. Having no siblings, compared to three or more siblings, was associated with significantly higher risk of lifetime history of hay fever (odds ratios (OR) 1.53, 95% confidence interval (CI) 1.25-1.86) and atopic eczema (OR 1.28, 95%CI 1.04-1.56), and higher risk (ns) of doctor-diagnosed asthma ever (OR 1.26, 95%CI 0.85-1.88). Less strong associations were observed with the number of older siblings (birth order). No associations were observed with current symptoms of these diseases during the last 12 mo. Attending a day care centre at the age of 1-3 y was not associated with decreased risk of any of the atopic diseases studied, but, in contrast to the hypothesis, was associated with slightly increased risk of current symptoms of hay fever (OR 1.34, 95%CI 1.12-1.60). The present results suggest that other factors than early childhood respiratory infections explain the association between number of siblings and future risk of atopic disease.
Age Factors↗
Maternal infections in pregnancy and the development of asthma among offspring.
BACKGROUND: Previous studies have suggested that asthma phenotype could probably be programmed before birth. The current study examined the impact of maternal vaginitis and febrile infections during pregnancy on the subsequent development of asthma among children. METHODS: The analyses were based on 8088 children from the northern Finland birth cohort, 1985-1986. RESULTS: The prevalence of asthma at age 7 was 3.5%. Children had a higher risk of asthma if their mothers experienced vaginitis and febrile infections during pregnancy, odds ratio (OR) = 1.41, (95% CI: 1.08-1.84) and 1.65 (95% CI: 1.25-2.18), respectively, after adjusting for other covariates. There was a clear time trend in risk of childhood asthma corresponding to the timing of maternal febrile infections in pregnancy. The adjusted OR for the first, second and third trimesters were 2.08 (95% CI: 1.13-3.82), 1.73 (95% CI: 1.09-2.75) and 1.44 (95% CI: 0.97-2.15), respectively. Maternal history of allergic diseases, birthweight <2500 g and male gender also seemed to be risk factors for childhood asthma. CONCLUSIONS: Our results suggest that further investigation of the relation of maternal infections during pregnancy to asthma among children seems warranted.
Adolescent↗
Inhomogeneity in response to air pollution in European children (PEACE project).
OBJECTIVES: The PEACE study is a multicentre panel study of the acute effects of particles with a 50% cut off aerodynamic diameter of 10 microns (PM10), black smoke (BS), sulphur dioxide (SO2), and nitrogen dioxide (NO2) on respiratory health of children with chronic respiratory symptoms. In the complete panels no consistent association between air pollution and respiratory health was found. The study evaluated whether potentially more sensitive subgroups in the panels did show effects of air pollution. METHODS: To evaluate heterogeneity in response to air pollution, effect estimates of air pollution on peak expiratory flow (PEF) and respiratory symptoms were calculated in subgroups based on presence of chronic respiratory symptoms, use of respiratory medication, atopy, sex, and baseline lung function. RESULTS: The association between PEF and air pollution was positive in asthmatic children who used respiratory medication whereas the associations tended to be negative in children who did not use respiratory medication selected only on cough. No consistent association was found among asthmatic children who did not use medication. The association between daily prevalence of symptoms and concentrations of air pollution was not different between these subgroups. CONCLUSION: None of the predefined potentially more sensitive subgroups showed a consistent association between air pollution, PEF, and respiratory symptoms.
Air Pollutants↗
How much asthma is really attributable to atopy?
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Asthma↗
Arsenic concentrations in well water and risk of bladder and kidney cancer in Finland.
We assessed the levels of arsenic in drilled wells in Finland and studied the association of arsenic exposure with the risk of bladder and kidney cancers. The study persons were selected from a register-based cohort of all Finns who had lived at an address outside the municipal drinking-water system during 1967-1980 (n = 144,627). The final study population consisted of 61 bladder cancer cases and 49 kidney cancer cases diagnosed between 1981 and 1995, as well as an age- and sex-balanced random sample of 275 subjects (reference cohort). Water samples were obtained from the wells used by the study population at least during 1967-1980. The total arsenic concentrations in the wells of the reference cohort were low (median = 0.1 microg/L; maximum = 64 microg/L), and 1% exceeded 10 microg/L. Arsenic exposure was estimated as arsenic concentration in the well, daily dose, and cumulative dose of arsenic. None of the exposure indicators was statistically significantly associated with the risk of kidney cancer. Bladder cancer tended to be associated with arsenic concentration and daily dose during the third to ninth years prior to the cancer diagnosis; the risk ratios for arsenic concentration categories 0.1-0.5 and [Greater/equal to] 0.5 microg/L relative to the category with < 0.1 microg/L were 1.53 [95% confidence interval (CI), 0.75-3.09] and 2.44 (CI, 1.11-5.37), respectively. In spite of very low exposure levels, we found some evidence of an association between arsenic and bladder cancer risk. More studies are needed to confirm the possible association between arsenic and bladder cancer risk at such low exposure levels.
Arsenic↗
[An international epidemiologic comparison of allergies].
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Environmental Exposure↗
The effect of particulate air pollution on life expectancy.
Two recent US cohort studies suggest that current levels of particulate pollution in urban air are associated not only with short-term, but also with long-term increases in cardiorespiratory morbidity and mortality. The aim of the present analyses was to evaluate the change in life expectancy assuming the long-term increase in mortality rates as suggested by these studies. The method of competing causes of death was used and the effect of particulate air pollution on life expectancy was found to be notable in countries with high cardiovascular mortality like the US.
Adolescent↗
Serum cholesterol distribution and coronary heart disease risk: observations and predictions among middle-aged population in eastern Finland.
BACKGROUND: The purpose of the present study was to assess the implications of cholesterol distribution and its change on coronary heart disease (CHD) mortality and disease prevention at a population level. METHODS AND RESULTS: In five independent risk factor surveys (1972, 1977, 1982, 1987, and 1992) in eastern Finland, serum cholesterol was measured in 27721 randomly selected men and women aged 30 to 59 years. The association between cholesterol level and CHD risk and the prediction of the effect of different prevention strategies was estimated by use of logistic regression models. The entire cholesterol distribution of the population shifted markedly toward lower levels between 1972 and 1992. The proportion of subjects with a very high cholesterol level (> or =8.0 mmol/L), also decreased markedly, from 16% to 3%. The risk of CHD death among subjects with cholesterol > or =8.0 mmol/L was approximately 5-fold that of those individuals having cholesterol <5.0 mmol/L. Nevertheless, because CHD risk increases continuously as serum cholesterol increases, and because the number of people having only slightly or moderately increased serum cholesterol was large, most CHD deaths occurred among them. A 10% reduction in cholesterol levels in the entire population would subsequently reduce CHD mortality by 20%, as much as an effective treatment as a 25% decrease in serum cholesterol among all subjects with cholesterol >6.5 mmol/L and four times more than similar treatment of all subjects with cholesterol > or =8.0 mmol/L. CONCLUSIONS: The community-based population strategy in cardiovascular disease prevention was effective in decreasing cholesterol levels among the entire population, including the subjects with the highest cholesterol values. The balanced application of both high-risk and population strategies is needed for the effective prevention of CHD.
Adult↗