Biomedical subjects

S J Dutton

Publications and source records attributed to S J Dutton.

4 recordsLinked to original sources

PubMed2001

Indoor pollutant levels from the use of unvented natural gas fireplaces in Boulder, Colorado.

High CO and NO2 concentrations have been documented in homes with unvented combustion appliances, such as natural gas fireplaces. In addition, polycyclic aromatic hydrocarbons (PAH) are emitted from incomplete natural gas combustion. The acute health risks of CO and NO2 exposure have been well established for the general population and for certain high-risk groups, including infants, the elderly, and people with heart disease or asthma. Health effects from PAH exposure are less well known, but may include increased risk of cancer. We monitored CO emissions during the operation of unvented natural gas fireplaces in two residences in Boulder, CO, at various times between 1997 and 2000. During 1999, we expanded our tests to include measurements of NO2 and PAH. Results show significant pollutant accumulation indoors when the fireplaces were used for extended periods of time. In one case, CO concentrations greater than 100 ppm accumulated in under 2 hr of operation; a person at rest exposed for 10 hr to this environment would get a mild case of CO poisoning with an estimated 10% carboxyhemoglobin level. Appreciable NO2 concentrations were also detected, with a 4-hr time average reaching 0.36 ppm. Similar time-average total PAH concentrations reached 35 ng/m3. The results of this study provide preliminary insights to potential indoor air quality problems in homes operating unvented natural gas fireplaces in Boulder.

Air Pollution, Indoor↗

PubMed1995

Controlling for socioeconomic confounding using regression methods.

STUDY OBJECTIVE: To describe the advantages of using Poisson regression methods as an alternative to standardisation when computing expected numbers of disease occurrences adjusted for possible confounding factors. The problem of assessing the adequacy of model fit when the expectations are small is addressed by analytical calculations and by simulation. The method is illustrated with data from the national register of childhood tumours. DESIGN: The tumour data are recorded in a national register. SETTING: England, Scotland, and Wales. SUBJECTS: The cases considered are all children registered with leukaemia or non-Hodgkin lymphoma under the age of 15 years between 1966-87. MAIN RESULTS: The methods show a significant variation of leukaemia incidence in relation to the Register General's standard region and a negative association with socioeconomic deprivation, as measured by the Townsend index. After allowing for these variables, the incidence seems to be reasonably homogeneous throughout the population, in the sense that the residual deviance does not seem to be much larger than would be expected by chance. CONCLUSIONS: The methods described have major advantages over standardisation in controlling for confounding, both in terms of flexibility of factor selection and assessment and also in the ability to determine whether there is residual variability of incidence after allowing for these factors.

Child, Preschool↗

PubMed1991

Ascertainment of congenital malformations: a comparative study of two systems.

STUDY OBJECTIVE: The aim was to compare the Office of Population Censuses and Surveys (OPCS) notification system for congenital malformation surveillance and the Liverpool Congenital Malformations Registry (LCMR) with respect to efficiency and uniformity of ascertainment, diagnostic accuracy, and overreporting of minor malformations. DESIGN: Manual matching of computer listings was done, using date of birth, sex, birthweight, and health district of residence. Maternal age was used to confirm the match. SETTING: Data were collected in the English health districts of Liverpool, St Helens and Knowsley, Southport and Formby, South Sefton, and Wirral over the years 1980-1985. SUBJECTS: 1959 malformed children notified to OPCS and 2649 notified to LCMR were assessed. MAIN RESULTS: 35.5% of malformed children ascertained by LCMR within seven days of birth were not notified to OPCS; 35.7% of cases reported to OPCS were exclusions from the LCMR protocol as being trivial malformations according to EUROCAT (European Registry of Congenital Anomalies) guidelines. Misclassification was infrequent but in 11.2% of cases the additional malformations present were not notified to OPCS. Conditions readily diagnosed at birth, such as neural tube defects, exomphalos, and facial clefts, were well ascertained by OPCS but others such as oesophageal atresia and Down's syndrome were not. CONCLUSIONS: It is important that national surveillance of congenital malformations should continue. However, several modifications to the present OPCS monitoring system are necessary, including greater standardisation of data collection, the exclusion of trivial and clinically non-significant malformations, and the inclusion of data on therapeutic abortions performed for fetal abnormality. These issues are being addressed by OPCS.

Congenital Abnormalities↗

PubMedDate not supplied

Distribution of childhood leukaemias and non-Hodgkin's lymphomas near nuclear installations in England and Wales.

OBJECTIVE: To examine the relation between the risk of childhood leukaemia and non-Hodgkin's lymphoma and proximity of residence to nuclear installations in England and Wales. DESIGN: Observed and expected numbers of cases were calculated and analysed by standard methods based on ratios of observed to expected counts and by a new statistical test, the linear risk score test, based on ranks and designed to be sensitive to excess incidence in close proximity to a putative source of risk. SETTING: Electoral wards within 25 km of 23 nuclear installations and six control sites that had been investigated for suitability for generating stations but never used. SUBJECTS: Children below age 15 in England and Wales, 1966-87. MAIN OUTCOME MEASURE: Registration of any leukaemia or non-Hodgkin's lymphoma. RESULTS: In none of the 25 km circles around the installations was the incidence ratio significantly greater than 1.0. The only significant results for the linear risk score test were for Sellafield (P = 0.00002) and Burghfield (P = 0.031). The circles for Aldermaston and Burghfield overlap; the incidence ratio was 1.10 in each. One of the control sites gave a significant linear risk score test result (P = 0.020). All the tests carried out were one sided with P values estimated by simulation. CONCLUSION: There is no evidence of a general increase of childhood leukaemia or non-Hodgkin's lymphoma around nuclear installations. Apart from Sellafield, the evidence for distance related risk is very weak.

Adolescent↗