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Biomedical subjects

D P Strachan

Publications and source records attributed to D P Strachan.

At least 55 records · Page 3Linked to original sources
PubMed1999

The effects of adiposity and weight change on forced expiratory volume decline in a longitudinal study of adults.

OBJECTIVE: To investigate whether changes in anthropometric measures are related to lung function decline. DESIGN: A national 7-y follow up study in Great Britain. SUBJECTS: 3391 adults aged 18-73 y at baseline. MEASUREMENTS: The primary outcome measure was change in forced expiratory volume in one second (Delta FEV1), adjusted for age, height and sex. This was related to changes in weight, body mass index, waist circumference, hips circumference and waist to hip ratio. RESULTS: Changes in weight, body mass and waist circumference, adjusted for confounders including mean level, were all associated with changes in FEV1 (P<0.001), with all effects stronger in men than women (P<0.05). Change in waist to hip ratio was related in men (P=0.01), but not in women (P=0.34). A 10 kg weight increase induced an additional fall in FEV1 of 96 ml (95% confidence interval (95% CI 65-127 ml) in men, and 51 ml (95% CI. 27-75 ml) in women. In men, the effect increased with average weight and obesity and was more pronounced in middle age. This phenomenon was not present in women, possibly due to gender differences in weight distribution in later adult life. Smoking did not appear to influence the magnitude of effect in either sex. The detrimental effect of weight gain on FEV1 in subjects that stopped smoking between studies appeared small in comparison to the benefit of smoking cessation. CONCLUSION: Increases in adult body mass are predictors of FEV1 decline, especially among older and heavier men, where weight reduction may significantly slow lung function decline.

Adolescent↗
PubMed1999

Prevalence of rhinitis, pillow type and past and present ownership of furred pets.

BACKGROUND: There has been no previous work investigating the effects of furred pet ownership and pillow type on the risk of developing rhinitis. Recently, unexpected and unexplained associations of asthma with nonfeather pillows have been reported. OBJECTIVE: We developed a questionnaire-based cross-sectional survey to determine whether the past or present ownership of cats or dogs, or the use of nonfeather pillows contributes to the development of seasonal or perennial rhinitis. METHODS: We surveyed 2555 accompanying friends and relatives of patients attending the outpatients departments at one London hospital in 1996. Individuals with rhinitis were defined as those suffering with three or more symptoms of rhinitis either throughout the year (perennial) or for part of the year (seasonal). Present or childhood ownership of cats or dogs was recorded. RESULTS: A strong association was seen with nonfeather pillow use and both seasonal [odds ratio (OR) 1.85; 95% confidence interval (CI) 1.43-2.5] and perennial (OR 2.63; CI 1.67-5. 0) rhinitis. However, more than one-third of rhinitics had changed their pillow type. After restricting the data to exclude subjects who changed their pillow to avoid allergies, the strong association of nonfeather pillow use with perennial rhinitis remained (OR 2.44; CI 1.25-5.0). Adjusting the data to the extreme situation where all former pillow type was feather changes the apparent risk to 0.99 (CI 0.67-1.43). No associations for either seasonal or perennial rhinitis were seen for feather pillows. A weak association of current dog ownership is demonstrated for seasonal rhinitis (OR 1. 47; CI 1.01-2.14). No associations were seen for childhood dog ownership or cat ownership at any time with either type of rhinitis. CONCLUSIONS: Feather pillow use and the ownership of furred pets appears unlikely to increase the risk of developing perennial or seasonal rhinitis. In fact, in contrast with currently held views, there is evidence that the use of nonfeather pillows may increase the risk.

Animals↗
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

The epidemiology of childhood asthma.

Variability is the hallmark of childhood asthma. Conceptually defined as variable airflow obstruction, asthma affects individual children through a variety of clinical manifestations. Particular controversy surrounds the nature of wheezing in early infancy and its relationship to atopic asthma of later onset. Asthma prognosis is also highly variable and only to a limited extent predictable by clinical indicators in early childhood. Long-term follow-up studies suggest a complex pattern of remission and relapse as wheezy children are followed through adolescence into adult life. Similarly, the population burden of asthma is highly variable, both over time and between countries. The balance of evidence worldwide suggests a modest but sustained increase in the prevalence of asthma symptoms over the past three decades. Superimposed on this have been larger changes in diagnostic fashion and use of health services for childhood asthma in many countries. There is substantial international variation in the prevalence of asthma symptoms, and marked urban-rural differences have been reported from several African countries. These contrast with the more uniform distribution of the disease within industrialized countries, reflecting its ubiquity in affluent societies.

Asthma↗
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

Cytomegalovirus seropositivity and incident ischaemic heart disease in the Caerphilly prospective heart disease study.

OBJECTIVE: To assess the role of cytomegalovirus (CMV) infection in primary ischaemic heart disease. METHODS: Plasma specimens collected during 1979-83 from men in Caerphilly, south Wales, were analysed for IgG antibodies to CMV by enzyme linked immunosorbent assay and latex tests. Incident ischaemic heart disease events were ascertained after five and 10 years from death certificates, hospital records, and ECG changes; 195 incident ischaemic heart disease cases were compared with 216 controls of a similar age drawn from the rest of the cohort. RESULTS: 164 cases (84%) and 180 controls (83%) were seropositive for CMV. Optical density, an indicator of CMV antibody titre, was similar for cases and controls. Among controls, seropositivity was not associated with age, socioeconomic status currently or in childhood, smoking, height, body mass index, blood pressure, total cholesterol, fibrinogen, plasma viscosity, or leucocyte count. The unadjusted odds ratio relating CMV seropositivity to incident ischaemic heart disease was 1.06 (95% confidence interval 0.63 to 1.79) and was little changed (1.11, 0.63 to 1.97) after adjustment for age, smoking, body mass index, systolic blood pressure, total cholesterol, and socioeconomic status currently and in childhood. CONCLUSIONS: CMV infection is unlikely to be a strong risk factor for development of myocardial infarction in middle aged men.

Antibodies, Viral↗
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

Health effects of passive smoking-10: Summary of effects of parental smoking on the respiratory health of children and implications for research.

BACKGROUND: Two recent reviews have assessed the effect of parental smoking on respiratory disease in children. METHODS: The results of the systematic quantitative review published as a series in Thorax are summarised and brought up to date by considering papers appearing on Embase or Medline up to June 1998. The findings are compared with those of the review published recently by the Californian Environmental Protection Agency (EPA). Areas requiring further research are identified. RESULTS: Overall there is a very consistent picture with odds ratios for respiratory illnesses and symptoms and middle ear disease of between 1.2 and 1.6 for either parent smoking, the odds usually being higher in pre-school than in school aged children. For sudden infant death syndrome the odds ratio for maternal smoking is about 2. Significant effects from paternal smoking suggest a role for postnatal exposure to environmental tobacco smoke. Recent publications do not lead us to alter the conclusions of our earlier reviews. While essentially narrative rather than systematic and quantitative, the findings of the Californian EPA review are broadly similar. In addition they have reviewed studies of the effects of environmental tobacco smoke on children with cystic fibrosis and conclude from the limited evidence that there is a strong case for a relationship between parental smoking and admissions to hospital. They also review data from adults of the effects of acute exposure to environmental tobacco smoke under laboratory conditions which suggest acute effects on spirometric parameters rather than on bronchial hyperresponsiveness. It seems likely that such effects are also present in children. CONCLUSIONS: Substantial benefits to children would arise if parents stopped smoking after birth, even if the mother smoked during pregnancy. Policies need to be developed which reduce smoking amongst parents and protect infants and young children from exposure to environmental tobacco smoke. The weight of evidence is such that new prevalence studies are no longer justified. What are needed are studies which allow comparison of the effects of critical periods of exposure to cigarette smoke, particularly in utero, early infancy, and later childhood. Where longitudinal studies are carried out they should be analysed to look at the way in which changes in exposure are related to changes in outcome. Better still would be studies demonstrating reversibility of adverse effects, especially in asthmatic subjects or children with cystic fibrosis.

Adult↗
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

The effects of environmental tobacco smoke exposure on lung function in a longitudinal study of British adults.

Small effects of environmental tobacco smoke exposure on lung function have been demonstrated in many studies of children, but fewer studies have examined adults in this respect. We examined these relations in a 7-year longitudinal study of 1,623 British adults, age 18-73 years, who were nonsmokers throughout. Outcome was measured by forced expiratory volume in 1 second (FEV1) adjusted for sex, age, and height. Exposure was assessed by asking subjects whether they lived with a smoker (at both the initial and the follow-up studies) and by salivary cotinine measurements (follow-up study only). Cross-sectionally, subjects exposed at home showed tiny FEV1 deficits at both studies of -4 ml [95% confidence limits (CL) = -31, 23] and -5 ml (95% CL = -32, 22), respectively. Cotinine adjusted for potential confounders showed a stronger association with FEV1, with the highest quintile showing a -105-ml deficit (95% CL = -174, -37) in comparison with the lowest. Longitudinally, no clear relation was apparent between change in FEV1 and average exposure or change in exposure. These results indicate that environmental tobacco smoke is associated with small deficits in adult lung function, consistent with our meta-analysis estimate of a 2.7% deficit in exposed nonsmoking adults. The relations seen with cotinine but not with household exposure may reflect the importance of exposure outside the home.

Adolescent↗
PubMed1998

Relation of Helicobacter pylori infection to 13-year mortality and incident ischemic heart disease in the caerphilly prospective heart disease study.

BACKGROUND: Associations have been suggested between Helicobacter pylori seropositivity, cardiovascular risk factors, and ischemic heart disease (IHD). The effect of this common infection on mortality is uncertain. METHODS AND RESULTS: Plasma specimens collected during 1979 to 1983 from 1796 men in Caerphilly, South Wales, were analyzed for IgG antibodies to H pylori. Cause of death and occurrence of incident IHD events were ascertained over an average of 13.7 years from death certificates, hospital records, and ECG changes at 5-yearly follow-up examinations. Seventy percent of men were seropositive. The prevalence of IHD at entry was similar in men with and without H pylori antibodies (odds ratio [OR], 1.10; 95% CI, 0.87 to 1.40). Seropositivity was significantly (P<0.05) associated with poorer socioeconomic status currently and in childhood, shorter stature, and poorer ventilatory function at entry but not with age, smoking, body mass index, blood pressure, total cholesterol, HDL cholesterol, LDL cholesterol, fibrinogen, plasma viscosity, or heat shock protein antibodies. Thirteen-year incidence of IHD was not significantly associated with H pylori (OR, 1.05; 95% CI, 0.80 to 1.39), but there was a stronger relationship with all-cause mortality (OR, 1.46; 95% CI, 1.12 to 1.92) and fatal IHD (OR, 1.54; 95% CI, 1.03 to 2.30). After adjustment for cardiovascular risk factors and both adult and childhood socioeconomic status, ORs were slightly reduced and lost statistical significance (OR=1.32 [95% CI, 0.99 to 1.78] for all-cause mortality and OR=1.52 [95% CI, 0.99 to 2.34] for fatal IHD). CONCLUSIONS: H pylori infection is unlikely to be as strong a risk factor for IHD as some previous studies have suggested, but its relationship to mortality, including fatal IHD, deserves further investigation. The mechanism underlying these associations is unlikely to involve hypertension, circulating lipid profile, fibrinogen, or cross-reacting antibodies to bacterial heat shock proteins.

Helicobacter Infections↗
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

The natural history of childhood eczema: observations from the British 1958 birth cohort study.

The National Child Development Study (NCDS) is a birth cohort study whose longitudinal design makes it suitable for examining the natural history of common diseases in childhood such as atopic eczema. We have analysed the age of onset and clearance rates for examined and/or reported eczema in 6877 children born during the period 3-9 March 1958 for whom linked data were available at birth and at the ages of 7, 11, 16 and 23 years. Of the 870 cases with examined or reported eczema by the age of 16 years, 66% had age of onset by the age of 7 years. Of the 571 children with reported or examined eczema by the age of 7 years, the proportion of children who were clear in terms of examined eczema or reported eczema in the last year at ages 11 and 16 years was 65% and 74%, respectively. These 'apparent' or short-term clearance rates fell to 53% and 65%, respectively, after allowance for subsequent recurrences in adolescence and early adulthood. Age of onset of community-ascertained cases of atopic eczema may be later than that reported in hospital-based studies. The long-term prognosis of childhood eczema may be worse than some previous studies have suggested, especially when subsequent recurrences are taken into account.

Adolescent↗
PubMed1998

Non-gastrointestinal consequences of Helicobacter pylori infection.

Evidence relating H. pylori to non-gastrointestinal disease is sparse and inconclusive. Suggested mechanisms whereby infection might increase cardiovascular risk include release of acute-phase reactants including fibrinogen, reduction of HDL cholesterol, elevation of homocysteine levels and immunological cross-reactivity between bacterial and human heat shock proteins. Six published studies relating H. pylori seropositivity to various measures of ischaemic heart disease (IHD)-angiography, acute myocardial infarction, angina symptoms, or electro-cardiographic abnormalities-are all consistent with a modest (up to 2-fold) elevation in risk of IHD among infected subjects after adjustment for age, socioeconomic status and conventional cardiovascular risk factors. The pooled odds ratio from 1 longitudinal, 3 case-control and 2 cross-sectional studies is 1.4 (95% confidence interval 1.1-1.8). Further large-scale longitudinal studies are required to quantify the predictive value of seropositivity, to clarify the causal interpretation and to assess the underlying mechanisms for any link between H. pylori infection and ischaemic heart disease.

Child↗