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H R Anderson

Publications and source records attributed to H R Anderson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Particulate matter and daily mortality and hospital admissions in the west midlands conurbation of the United Kingdom: associations with fine and coarse particles, black smoke and sulphate.

OBJECTIVES: There is considerable evidence linking ambient particles measured as particulate matter with aerodynamic diameter <10 microm (PM(10)) to daily mortality and hospital admissions but it is not clear which physical or chemical components of the particle mixture are responsible. The relative effects of fine particles (PM(2.5)), coarse particles (PM(2.5-10)), black smoke (mainly fine particles of primary origin) and sulphate (mainly fine particles of secondary origin) were investigated, together with ozone, SO(2), NO(2), and CO, on daily mortality and hospital admissions in the west Midlands conurbation of the United Kingdom. METHODS: Time series of health outcome and environmental data were obtained for the period 1994-6. The relative risk of death or hospital admission was estimated with regression techniques, controlling for long term time trends, seasonal patterns, influenza epidemics, effects of day of the week, and temperature and humidity. Models were adjusted for any remaining residual serial correlation and overdispersion. The sensitivities of the estimates for the effects of pollution to the inclusion of a second pollutant and seasonal interactions (warm or cool) were also examined. RESULTS: Daily all cause mortality was not associated with any gaseous or particulate air pollutant in the all year analysis, although all measures of particles apart from PM(2.5-10) showed significant positive effects of the warm season. Neither respiratory nor cardiovascular admissions (all ages) were associated with any air pollutant, and there were no important seasonal interactions. However, analysis of admissions by age found evidence for various associations-notably between PM(10), PM(2.5), black smoke, SO(2,) and ozone (negative) and respiratory admissions in the 0-14 age group. The coarse fraction, PM(2.5-10) differed from PM(2.5) in having smaller and less consistent associations (including several large significant negative associations) and a different lag distribution. The results for black smoke, an indicator of fine primary carbonaceous particles, were very similar to those for PM(2.5), and tended to be more robust in two pollutant models. The effects of sulphate, an indicator of secondary particles, also showed some similarities to those of PM(2.5). CONCLUSIONS: Clear effects of air pollution on mortality and hospital admissions were difficult to discern except in certain age or diagnostic subgroups and seasonal analyses. It was also difficult to distinguish between different measures of particles. Within these limitations the results suggest that the active component of PM(10) resides mostly in the fine fraction and that this is due mainly to primary particles from combustion (mainly vehicle) sources with a contribution from secondary particles. Effects of the coarse fraction cannot be excluded.

Adolescent↗
PubMed2001

Investigating regional differences in short-term effects of air pollution on daily mortality in the APHEA project: a sensitivity analysis for controlling long-term trends and seasonality.

Short-term effects of air pollution on daily mortality in eight western and five central-eastern European countries have been reported previously, as part of the APHEA project. One intriguing finding was that the effects were lower in central-eastern European cities. The analysis used sinusoidal terms for seasonal control and polynomial terms for meteorologic variables, but this is a more rigid approach than the currently accepted method, which uses generalized additive models (GAM). We therefore reanalyzed the original data to examine the sensitivity of the results to the statistical model. The data were identical to those used in the earlier analyses. The outcome was the daily total number of deaths, and the pollutants analyzed were black smoke (BS) and sulfur dioxide (SO(2)). The analyses were restricted to days with pollutant concentration < 200 microg/m(3) and < 150 microg/m(3) alternately. We used Poisson regression in a GAM model, and combined individual city regression coefficients using fixed and random-effect models. An increase in BS by 50 microg/m(3) was associated with a 2.2% and 3.1% increase in mortality when analysis was restricted to days < 200 microg/m(3) and < 150 microg/m(3), respectively. The corresponding figures were 5.0% and 5.6% for a similar increase in SO(2). These estimates are larger than the ones published previously: by 69% for BS and 55% for SO(2). The increase occurred only in central-eastern European cities. The ratio of western to central-eastern cities for estimates was reduced to 1.3 for BS (previously 4.8) and 2.6 for SO(2) (previously 4.4). We conclude that part of the heterogeneity in the estimates of air pollution effects between western and central-eastern cities reported in previous publications was caused by the statistical approach used and the inclusion of days with pollutant levels above 150 microg/m(3). However, these results must be investigated further.

Adolescent↗
PubMed2001

Immunization and symptoms of atopic disease in children: results from the International Study of Asthma and Allergies in Childhood.

OBJECTIVES: This study tested the hypothesis that immunization is related to the prevalence of atopic disease in childhood. METHODS: We used data from the International Study of Asthma and Allergies in Childhood to perform an ecologic analysis of national and local immunization rates for tuberculosis, diphtheria and tetanus toxoids and pertussis (DTP), and measles and prevalence of atopic disease symptoms (asthma, allergic rhinoconjunctivitis, and atopic eczema). RESULTS: In 13- to 14-year-old children, there were significant negative associations with local birth-year immunization rates for DTP and measles but none with rates for tuberculosis. No associations were found in 6- to 7-year-old children. No associations with national immunization rates were found. CONCLUSIONS: International variations in childhood atopic diseases are unlikely to be explained by variations in immunization.

Adolescent↗
PubMed2000

Daily concentrations of air pollution and plasma fibrinogen in London.

OBJECTIVES: The reason for the association between air pollution and risk of cardiovascular diseases is unknown. The hypothesis was examined that daily concentrations of air pollution are associated with daily concentrations of fibrinogen, a risk factor for cardiovascular disease. METHODS: Data on concentrations of plasma fibrinogen for 4982 male and 2223 female office workers, collected in a cross sectional survey in London between September 1991 and May 1993, were combined with data on concentrations of air pollution during the day of blood sampling and during the 3 preceding days. RESULTS: After adjustment for weather and other confounding factors, an increase in the 24 hour mean NO(2) during the previous day from the 10th to the 90th percentile (61.7 microg/m(3)) was associated with a 1.5% (95% confidence interval (95% CI) 0.4% to 2.5%) higher fibrinogen concentration. The respective increase for CO (1.6 mg/m(3)) was 1.5% (95% CI 0.5%, 2.5%). These associations tended to be stronger in the warm season (April to September). Significant associations were found for black smoke and particulate matter of diameter 10 microm (PM(10)) only in the warm season. No association with fibrinogen was found for SO(2) or ozone. CONCLUSIONS: The short term association between air pollution, possibly from traffic, and risk of cardiovascular events may be at least partly mediated through increased concentrations of plasma fibrinogen, possibly due to an inflammatory reaction caused by air pollution.

Adult↗
PubMed2000

Comparison of asthma prevalence in the ISAAC and the ECRHS. ISAAC Steering Committee and the European Community Respiratory Health Survey. International Study of Asthma and Allergies in Childhood.

International and regional prevalence comparisons are required to test and generate hypotheses regarding the causes of increasing asthma prevalence in various age groups worldwide. The International Study of Asthma and Allergies in Childhood (ISAAC) is the first such study in children and the European Community Respiratory Health Survey (ECRHS) is the first such study in adults. Therefore, a comparison of the findings of these two surveys was conducted, for the 17 countries in which both surveys were undertaken. There was a strong correlation between the ISAAC and ECRHS prevalence data, with 64% of the variation at the country level, and 74% of the variation at the centre level, in the prevalence of "wheeze in the last 12 months" in the ECRHS phase I data being explained by the variation in the ISAAC phase I data. There was also generally good agreement in the international patterns observed in the two surveys for self-reported asthma (74% of country level and 36% of centre level variation explained), self-reported asthma before age 14 yrs (64 and 26%), hay fever (61 and 73%) and eczema (41 and 50%). Thus although there were differences in the absolute levels of prevalence observed in the two surveys, there is good overall agreement between the International Study of Asthma and Allergies in Childhood and European Community Respiratory Health Survey study findings with regard to international prevalence patterns. These findings, therefore, add support to the validity of the two studies, which provide a new picture of global patterns of asthma prevalence from child- to adulthood, and identify some of the key phenomena which future research must address.

Adolescent↗
PubMed1999

Fresh fruit intake and asthma symptoms in young British adults: confounding or effect modification by smoking?

Antioxidant vitamins have been postulated as a protective factor in asthma. The associations between the frequency of fresh fruit consumption in summer, and the prevalence of self-reported asthma symptoms were investigated. The analysis was based on 5,582 males and 5,770 females, born in England, Wales and Scotland between March 3-9, 1958 and aged 33 yrs at the time of survey. The 12-month period prevalence of wheeze and frequent wheeze were inversely associated with frequent intakes of fresh fruit and salad/raw vegetables and positively associated with smoking and lower social class. After adjustment for mutual confounding and sex, associations with smoking persisted, but those with social class and salad/raw vegetable consumption lost significance. The frequency of fresh fruit intake was no longer associated with wheeze after adjustment, but was inversely associated with frequent wheeze and speech-limiting attacks. The association with frequent wheeze differed significantly between smoking groups (never, former, current) and appeared to be confined to exsmokers and current smokers. These findings support postulated associations between infrequent fresh fruit consumption and the prevalence of frequent or severe asthma symptoms in adults. Associations appeared to be restricted to smokers, with effect modification as a more likely explanation of this pattern than residual confounding by smoking.

Adult↗
PubMed1999

Effects of exposure to gas cooking in childhood and adulthood on respiratory symptoms, allergic sensitization and lung function in young British adults.

BACKGROUND: There is evidence that people who use gas for cooking have reduced lung function and experience more respiratory symptoms than those who use other fuels for cooking. OBJECTIVES: To study the effect of the presence of a gas cooker in the home, during both childhood and adulthood, on respiratory symptoms, allergic sensitization and ventilatory function among young adults. METHODS: A sample of 1449 young adults born in Britain 3-9 March 1958, who have been followed from birth to ages 7, 11, 16, 23 and 33 years, were examined at home at age 34-35 years. FEV1 and FVC were measured before and 20 min after inhalation of 400 microg salbutamol, and skin prick tests performed with three allergen extracts (grass, Der p 1 and cat). An interview on respiratory symptoms and indoor environmental exposures was included. RESULTS: No association was found between gas cooking in childhood or adulthood and incidence or prognosis of asthma/wheeze, allergic sensitization or current severity of respiratory symptoms. Subjects who currently used gas for cooking had a significantly reduced FEV1 (- 70 mL, 95% CI +/- 56) but not FVC (- 35 mL, 95% CI +/- 61) compared with those who used electricity for cooking. This reduction in FEV1 was concentrated among men and current asthmatics. CONCLUSION: The use of gas for cooking is unlikely to be a major influence on respiratory morbidity in young adults.

Adult↗
PubMed1999

Hay fever, eczema, and wheeze: a nationwide UK study (ISAAC, international study of asthma and allergies in childhood).

OBJECTIVES: To describe the prevalence of atopic symptoms in children throughout the UK. METHOD: A questionnaire survey of 12-14 year olds throughout England, Wales, Scotland, and the Scottish Islands using the international study of asthma and allergies in childhood (ISAAC) protocol. RESULTS: A total of 27 507 (86%) children took part. Recent rhinoconjunctivitis was reported by 18.2%, with 6.2% reporting symptoms between March and September; 16.4% reported itchy flexural rash in the past 12 months. The prevalence of atopic symptoms was higher in girls and subjects born within the UK. The prevalence of severe wheeze was highest in subjects reporting perennial rhinoconjunctivitis, as opposed to summertime only symptoms. Winter rhinoconjunctivitis was associated with severe wheeze and severe flexural rash. One or more current symptoms were reported by 47.6% of all children and 4% reported all three symptoms. CONCLUSION: In general, geographical variations were small but the prevalence of symptoms was significantly higher in Scotland and northern England. The study demonstrates the importance of atopic diseases both in their own right and in association with asthma.

Adolescent↗
PubMed1999

Short-term associations between outdoor air pollution and mortality in London 1992-4.

OBJECTIVES: A previous study of the short term effects of air pollution in London from April 1987 to March 1992 found associations between all cause mortality and black smoke and ozone, but no clear evidence of specificity for cardiorespiratory deaths. London data from 1992 to 1994 were analysed to examine the consistency of results over time and to include particles with a mean aerodynamic diameter of 10 microns (PM10) and carbon monoxide. METHODS: Poisson regression was used of daily mortality counts grouped by age and diagnosis, adjusting for trend, seasonality, calendar effects, deaths from influenza, meteorology, and serial correlation. The pollutants examined were particles (PM10 and black smoke), nitrogen dioxide, ozone, sulphur dioxide, and carbon monoxide with single and cumulative lags up to 3 days. RESULTS: No significant associations were found between any pollutant and all cause mortality, but, with the exception of ozone, all estimates were positive. Each pollutant apart from ozone was significantly associated with respiratory mortality; PM10 showed the largest effect (4% increase in deaths of all ages for a 10th-90th percentile increment). The pollutants significantly associated with cardiovascular deaths were nitrogen dioxide, ozone, and black smoke but there was no evidence of an association with PM10. In two pollutant models of respiratory deaths, the effect of black smoke, which in London indicates fine particles of diesel origin, was independent of that of PM10, but not vice versa. CONCLUSION: These results from a new data set confirm a previous report that there are associations between various air pollutants and daily mortality in London. This new study found greater specificity for associations with respiratory and cardiovascular deaths, and this increases the plausibility of a causal explanation. However, the effects of ozone found in the earlier study were not replicated. The fraction of PM10 which comprises black smoke accounted for much of the effect of PM10.

Adolescent↗
PubMed1999

Respiratory symptoms and home environment in children: a national survey.

BACKGROUND: Respiratory diseases are common in childhood and may lead to chronic disease in adult life; environmental factors probably play an important part in their causation. METHODS: A survey of respiratory symptoms in children aged 12-14 years was conducted throughout Great Britain as part of the International Study of Asthma and Allergies in Childhood (ISAAC). Information was obtained on certain aspects of the home environment in order to assess their importance as risk factors. RESULTS: The response rate was 79.3%, and 25,393 children in 93 schools participated. In a multiple regression analysis, wheeze was reported more often in nonmetropolitan areas and in association with active smoking, passive smoking, the presence of a furry pet, bottled gas, paraffin, and other unusual heating fuels; small regional differences persisted. Current smoking, previous smoking, and passive smoking accounted for 10.4%, 6.8%, and 6.5%, respectively, of wheezing in the past 12 months, and furry pets accounted for 5.0%. Cough and phlegm were associated with active and passive smoking and with the miscellaneous fuels; similar associations were found for rhinitis, but were less consistent for rhinitis occurring in spring and summer. Gas cooking showed little association with respiratory symptoms. CONCLUSIONS: Passive as well as active smoking is an important cause of respiratory symptoms in adolescence. Pets seem to increase the risk of wheeze and rhinitis, and fumes from certain unusual heating fuels may have adverse effects. Home environment and geographical location have independent effects on the prevalence of respiratory symptoms.

Adolescent↗
PubMed1999

Association of air pollution with daily GP consultations for asthma and other lower respiratory conditions in London.

BACKGROUND: Very few published studies have looked at the effects of air pollution on health in the primary care setting. As part of a large study to examine the association between air pollution and a number of health outcomes, the relationship between daily GP consultations for asthma and other lower respiratory diseases (LRD) and air pollution in London was investigated. METHODS: Time-series analysis of daily numbers of GP consultations controlling for time trends, seasonal factors, day of week cycles, influenza, weather, pollen levels, and serial correlation was performed. Consultation data were available from between 268 718 and 295 740 registered patients from 45-47 London practices contributing to the General Practice Research Database during 1992-4. RESULTS: Positive associations, weakly significant and consistent across lags, were observed between asthma consultations and nitrogen dioxide (NO2) and carbon monoxide (CO) in children and particulate matter of less than 10 microm in diameter (PM10) in adults, and between other LRD consultations and sulphur dioxide (SO2) in children. A consistently negative association with ozone in children was observed in both disease categories. The effect estimates of most pollutants were much larger when analysed separately by season, particularly in the children: percentage change in asthma consultations during the warm season (April-September) for a 10-90th percentile increase in 24 hour NO2 lagged by one day = 13.2% (95% CI 5.6 to 21.3), with CO = 11.4% (95% CI 3.3 to 20.0), and with SO2 = 9.0% (95% CI 2.2 to 16.2). In adults the only association consistent over different lag periods was with PM10 = 9.2% (3.7 to 15.1). The associations of pollution and consultations for LRD were increased mainly in the winter months: percentage change in consultations by children in winter with NO2 = 7.2% (95% CI 2.8 to 11.6), CO = 6.2% (95% CI 2.3 to 10.2), and SO2 = 5.8% (95% CI 1.6 to 10.2). CONCLUSIONS: There are associations between air pollution and daily consultations for asthma and other lower respiratory disease in London. The most significant associations were observed in children and the most important pollutants were NO2, CO, and SO2. In adults the only consistent association was with PM10.

Adolescent↗
PubMed1999

Short-term associations between outdoor air pollution and visits to accident and emergency departments in London for respiratory complaints.

Many epidemiological studies have shown positive short-term associations between health and current levels of outdoor air pollution. The aim of this study was to investigate the association between air pollution and the number of visits to accident and emergency (A&E) departments in London for respiratory complaints. A&E visits include the less severe cases of acute respiratory disease and are unrestricted by bed availability. Daily counts of visits to 12 London A&E departments for asthma, other respiratory complaints, and both combined for a number of age groups were constructed from manual registers of visits for the period 1992-1994. A Poisson regression allowing for seasonal patterns, meteorological conditions and influenza epidemics was used to assess the associations between the number of visits and six pollutants: nitrogen dioxide, ozone, sulphur dioxide, carbon monoxide, and particles measured as black smoke (BS) and particles with a median aerodynamic diameter of <10 microm (PM10). After making an allowance for the multiplicity of tests, there remained strong associations between visits for all respiratory complaints and increases in SO2: a 2.8% (95% confidence interval (CI) 0.7-4.9) increase in the number of visits for a 18 microg x (-3) increase (10th-90th percentile range) and a 3.0% (95% CI 0.8-5.2) increase for a 31 microg x m(-3) increase in PM10. There were also significant associations between visits for asthma and SO2, NO2 and PM10. No significant associations between O3 and any of the respiratory complaints investigated were found. Because of the strong correlation between pollutants, it was difficult to identify a single pollutant responsible for the associations found in the analyses. This study suggests that the levels of air pollution currently experienced in London are linked to short-term increases in the number of people visiting accident and emergency departments with respiratory complaints.

Adolescent↗
PubMed1999

Recommendations for the monitoring of short-term health effects of air pollution: lessons from the APHEA Multi Centre European Study.

Accumulating evidence from European cities indicates that current levels of ambient air pollution are likely to be associated with detectable effects on daily mortality and hospital admissions. Public health authorities everywhere are concerned about the possible effects of air pollution on the health of their populations but there are no guidelines for how these effects can efficiently be monitored. Furthermore, decisions about air pollution monitoring tend to be made without reference to the epidemiological requirements of health monitoring. The APHEA project (Air Pollution and Health a European Approach) investigated the short-term health effects of air pollution in 15 European cities. Experience gained in this project provides a basis for recommendations to public health and environmental authorities concerning the requirements for a basic health monitoring system. This paper considers the theoretical and practical aspects of a monitoring system and makes recommendations concerning 1) the minimum data set required, 2) the methods of statistical analysis and presentation and 3) Europe-wide coordination of monitoring.

Air Pollution↗
PubMed1998

Effect of pneumonia and whooping cough in childhood on adult lung function.

BACKGROUND: Previous studies have suggested that respiratory infection during childhood is associated with respiratory disease in adulthood, but the link is unclear because of retrospective ascertainment of childhood infection, selection bias, and confounding factors. METHODS: We studied the effects of childhood pneumonia and whooping cough in 1392 British adults followed from birth in 1958. Of these, 193 had a history of pneumonia and 215 a history of whooping cough by the age of seven years. When the subjects were 34 or 35 years old, their forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were measured before and after they inhaled albuterol. RESULTS: A history of pneumonia was associated with deficits (+/-95 percent confidence limits) in both FEV1 (102+/-73 ml, P=0.006) and FVC (173+/-70 ml, P=0.001) when the analysis was adjusted for sex, height, and smoking, with no change in the ratio of FEV1 to FVC. These deficits persisted after inhalation of albuterol. In subjects with no history of wheezing, the deficit in FEV1 was 155+/-122 ml (P=0.01), in those with past wheezing it was 41+/-128 ml (P=0.53), and in those with current wheezing it was 119+/-133 ml (P=0.08). The effect was no greater for the subjects who had pneumonia at less than two years of age than for those who had it between the ages of two and seven years and was not diminished after control for multiple confounding factors. The deficits associated with whooping cough were smaller (FEV1, 41+/-70 ml; P=0.25; FVC, 81+/-76 ml; P=0.04). CONCLUSIONS: Childhood pneumonia is associated with reduced ventilatory function in adults. This reduction is independent of a history of wheezing and is not explained by other confounding factors.

Adult↗
PubMed1998

Prevalence of asthma symptoms, diagnosis, and treatment in 12-14 year old children across Great Britain (international study of asthma and allergies in childhood, ISAAC UK)

OBJECTIVE: To investigate variations in the prevalence of self reported symptoms, diagnosis, and treatment of asthma in 12-14 year old children. DESIGN: Self completion questionnaire. SETTING: Great Britain. SUBJECTS: All pupils aged 12-14 years in a stratified cluster sample of 93 large mixed secondary schools in 1995. MAIN OUTCOME MEASURES: Self reported prevalence of symptoms, diagnosis, and treatment of asthma at four geographical levels. RESULTS: 27,507 questionnaires were completed (85.9% response rate). The national 12 month prevalence of any wheezing, speech limiting wheeze, four or more attacks of wheeze, and frequent night waking with wheeze was 33.3% (n = 9155), 8.8% (2427), 9.6% (2634), and 3.7% (1023) respectively. The prevalence of ever having had a diagnosis of asthma was 20.9% (5736). In total, 19.8% (5438/27,507) of pupils reported treatment with anti-asthma drugs in the past year, but, of pupils reporting frequent nocturnal wheeze in the past year, 33.8% (342/1012) had no diagnosis of asthma and 38.6% (395/1023) denied receiving inhaler therapy. The 12 month prevalence of wheeze was highest in Scotland (36.7%, 1633/4444), but in England and Wales there was no discernible north-south or east-west gradient. Wheeze prevalence was slightly higher in non-metropolitan areas (35.0%, 6155/17,605) than in metropolitan areas (30.3%, 3000/9902). The prevalence of self reported asthma diagnosis and inhaler use showed no discernible national, regional, north-south, or east-west geographical pattern but was higher in non-metropolitan areas. CONCLUSION: Prevalence of self reported symptoms, diagnosis, and treatment of asthma was high among 12-14 year olds throughout Great Britain with little geographical or urban-rural variation. Underdiagnosis and undertreatment were substantial.

Adolescent↗
PubMed1998

Inappropriate use of daily mortality analyses to estimate longer-term mortality effects of air pollution.

BACKGROUND: To avoid the usual problems of multi-population correlation studies of air pollution and mortality, and for reasons of convenience, daily time-series mortality studies within single populations have recently become popular in air pollution epidemiology. Such studies describe how the short-term distribution of deaths relates to short-term fluctuations in air pollution levels. The regression-based risk coefficients from these acute-effects studies have been widely used to estimate the excess annual mortality within a population with a specified average level of air pollution. Such calculations are inappropriate. Since daily time-series data provide no simple direct information about the degree of life-shortening associated with the excess daily deaths (many of which are thought to be due to exacerbation of well-advanced disease, especially cardiovascular disease), such data cannot contribute to the estimation of the effects of air pollution upon chronic disease incidence and long-term death rates. Yet it is that category of effect that is of most public health importance. CONCLUSION: Such effects are best estimated from long-term cohort studies that incorporate good knowledge of local (or personal) exposure to air pollutants and of potential confounders. Time-series studies, properly evaluated, can identify the existence of acute toxic effects of transient peak levels of air pollution; they are thus useful for monitoring acute toxicity and for identifying the most noxious pollutants. However, to quantify the long-term health impacts of air pollution we cannot use acute-effects data.

Air Pollution↗