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Biomedical subjects

D P Strachan

Publications and source records attributed to D P Strachan.

136 records · Page 8Linked to original sources
PubMed1989

Damp housing and childhood asthma; respiratory effects of indoor air temperature and relative humidity.

In a questionnaire survey of a random sample of 1000 children aged 7 years, a significantly greater proportion of those living in homes reported as damp were affected by wheeze (22% v 11%), day cough, night cough, and chesty colds. Simultaneous estimation of relative humidity in the bedrooms of 778 children and continuous 7 day recordings of ambient temperature and humidity in a stratified sample of 317 bedrooms showed no association with the same respiratory symptoms. No correlation was found between bedroom conditions and baseline ventilatory function or exercise induced reduction in FEV1. These results run counter to the widely held belief that indoor temperature and humidity are important determinants of respiratory ill health, although they do not directly exclude effects due to mites or moulds, whose survival is determined by the humidity of their respective microenvironments.

Asthma↗
PubMed1989

Repeatability of ventilatory function measurements in a population survey of 7 year old children.

The within subject variability of forced vital capacity (FVC), forced expiratory volumes in one second (FEV1) and half a second (FEV0.5), peak expiratory flow (PEF), and flow rates at 25-75%, 75-85%, 25%, 50%, and 75% of expired FVC were assessed among 7 year old children from the general population. Within occasion variability in 232 children was lowest for FVC (coefficient of variation (CV) 5%) and FEV1 (CV 4%), and greatest for end expiratory flow rates. The precision of measurement for FEV1 supports its use for bronchial provocation tests, particularly those using a graded challenge. In this context the value of PEF (CV 7%) and mid expiratory flow rates (CV 11%) is limited by their poorer repeatability. Between occasion variability was assessed in 171 children tested at an interval of one to four weeks. The difference between the variances between occasions and within occasions was attributed to biological variation; this accounted for a substantial component of the between occasion variance in all indices, particularly FEV1 (73%) and PEF (66%). Together, within subject variability, sex, and height accounted for about half of the measured variance between subjects for all indices except FVC (68%). These results have implications for epidemiological studies.

Child↗
PubMed1988

Damp housing and childhood asthma: validation of reporting of symptoms.

The relations among parental reports of respiratory symptoms, bronchospasm measured after exercise, and the presence of visible fungal mould in the home was assessed in a population sample of 7 year old children (n = 873). Wheeze in the past year was the symptom most closely associated with reported dampness and particularly with mould. The unadjusted odds ratio relating mould and wheeze was 3.70 (95% confidence interval 2.22 to 6.15), and after adjustment for housing tenure, number of people per room, number of smokers in the household, and gas cooking this remained highly significant (odds ratio 3.00 (1.72 to 5.25)). The reduction in forced expiratory volume in one second after six minutes of free running was used to validate reporting of wheeze. At all levels of measured bronchial lability wheeze was reported more commonly in the children from homes with mould. There was no significant difference in the degree of bronchospasm measured among children from homes with and without mould. Awareness of dampness or mould in the home may be a determinant of parental reporting of symptoms and may account for much of the observed association between mould and respiratory symptoms.

Asthma↗
PubMed1988

Asthma as a link between chest illness in childhood and chronic cough and phlegm in young adults.

The link between chest illnesses in childhood to age 7 and the prevalence of cough and phlegm in the winter reported at age 23 was investigated in a cohort of 10,557 British children born in one week in 1958 (national child development study). Both pneumonia and asthma or wheezy bronchitis to age 7 were associated with a significant excess in the prevalence of chronic cough and phlegm at age 23 after controlling for current smoking. This excess was largely attributable to the association of cough and phlegm at age 23 with a history of asthma or wheezy bronchitis from age 16. When adjustment was made for recent wheezing, current cigarette consumption, previous smoking habit, and passive exposure to smoke the relative odds of cough or phlegm, or both, in subjects with a history of childhood chest illness was 1.11 (95% confidence interval 0.97 to 1.27). When analysed separately asthma, wheezy bronchitis, and pneumonia up to age 7 did not significantly increase the prevalence of either cough or phlegm. The explanation for the observed continuity between chest illness in childhood and respiratory symptoms in later life may lie more in the time course of functional disturbances related to asthma than in the persistence of structural lung damage.

Asthma↗
PubMed1987

Antenatal booking and perinatal mortality in Scotland 1972-1982.

Data from Scottish maternity hospital discharge returns (SMR2) were analysed to determine the relationship between gestational age at antenatal booking and perinatal mortality during 1972-82, controlling for maternal age, parity, socioeconomic and marital status. Maternal youth, multiparity and unmarried status were independently associated with both a high perinatal mortality and a low proportion of maternities booked before 17 weeks gestation. However, among primiparae and mothers aged 30 years or more relatively high perinatal mortality rates were associated with high proportions booking early for antenatal care. Socioeconomic status amongst married women, independent of age and parity, influenced perinatal mortality but had little effect on booking behaviour. Between 1972-75 and 1980-82, there was a general increase in the proportion of maternities booked before 17 weeks gestation, but no significant difference was found between the standardized perinatal mortality rates for pregnancies booked before and after 17 weeks gestation. More detailed analysis for different gestational ages at booking during 1980-82 revealed no trend of increasing risk with later booking. Despite technological advances, antenatal care during the first half of pregnancy is unlikely to have made a substantial contribution to the fall in perinatal mortality over this period.

Adult↗
PubMed1986

Relationship between respiratory morbidity in children and the home environment.

The relationships between 12 features of the home environment and respiratory morbidity as reported by parents, and as recorded in general practice records, were studied in 165 children aged seven to eight years. Parental reports of wheeze, nocturnal cough and school absence owing to chest trouble were significantly more common among children with a family history of wheeze, and those from damp or mouldy housing. There were associations between coal fires and nocturnal cough and between an open window and wheeze. Multivariate analyses confirmed these associations to be independent of each other, and of the child's sex and seven other features of the home environment, including gas appliances and parental smoking. These same environmental variables were not consistently related to general practice consultations for wheeze or lower respiratory illness. Damp and mouldy housing, coal fires and open bedroom windows should be investigated further as potentially remediable causes of respiratory disease in childhood.

Child↗
PubMed1985

Wheezing presenting in general practice.

General practice records of 1058 children were studied to determine the incidence, prevalence, natural history, diagnosis, and treatment of wheezing presenting in the first 21 years of life. Up to 7 years of age, boys were more likely to present with wheeze and to have recurrent episodes. Later there was a higher incidence in girls and a substantial rate of remission among boys, both contributing to changes in prevalence during later childhood and adolescence. All those diagnosed as asthmatic and two thirds of those with recurrent wheeze received bronchodilator treatment.

Adolescent↗
PubMed1985

The prevalence and natural history of wheezing in early childhood.

The general practice records of 437 children were reviewed at seven years of age. Of 369 children with complete records, 115 (31 per cent) had some record of wheeze. Over half of these had first presented before the age of three years. In terms of consultations for wheezing or lower respiratory tract illness at the ages of five to seven years, the earlier the onset of wheeze the better the prognosis.Comparison of data from parental questionnaires with the general practice records of 174 children suggested that parental recall of early episodes of wheeze is incomplete and biassed by the severity and persistence of the symptoms of the child. Questionnaire surveys may therefore have excluded many mild cases of wheezing in early childhood, thus underestimating the prevalance of wheezing in infancy, and overestimating the proportion of such cases who progress to persistent wheezing in later childhood.

Age Factors↗
PubMedDate not supplied

Short-term associations between emergency hospital admissions for respiratory and cardiovascular disease and outdoor air pollution in London.

There are concerns about the possible short-term effects of outdoor air pollution on health in the United Kingdom. In a study conducted during the time period between 1987 and 1992, investigators determined that ozone had small, but significant effects on emergency respiratory admissions. In the current study, the authors investigated associations between emergency admissions and outdoor air pollution for the time period from 1992 to 1994, inclusive, and compared the results with those obtained in the earlier study. The authors also examined particulate matter less than 10 microm in diameter (PM10) and carbon monoxide in the current study. Appropriate confounding factors, such as seasonal patterns, temperature, and humidity, were controlled for, and the authors used Poisson regression to estimate the association between daily emergency admissions for respiratory and cardiovascular diseases and ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, particles measured as Black Smoke, and PM10. Significant positive associations were found between emergency hospital admissions for respiratory disease and PM10 and sulfur dioxide, but such an association did not exist for ozone. The results were not significantly different from earlier results from London and were comparable with those determined in North America and Europe. Cardiovascular disease was associated with carbon monoxide and Black Smoke, but weaker associations existed with the other pollutants studied.

Adolescent↗