Showing papers by "Neil Pearce published in 1994"

Risk factors for asthma symptoms in kawerau children

Abstract: AIMS To study risk factors for asthma prevalence in Kawerau children aged 8-13 years. METHODS Questionnaires on asthma symptoms and risk factors were completed in 1992 by parents of 708 Kawerau schoolchildren aged 8-13 years, a response rate of 82.0%; for a subgroup of children, stored serum samples from a 1984 survey were also analysed. RESULTS The overall prevalence of current wheeze (21.3%) was similar to that observed in other New Zealand surveys. The prevalence of current wheeze was elevated in males (odds ratio (OR) = 1.7, 95% CI 1.2-2.5), in those who had been passively exposed to cigarette smoke from the primary caregiver (OR = 1.4, 95% CI 1.0-2.1), in those who had had pets in the home at age 0-5 years (OR = 1.9, 95% CI 1.2-2.9) and in those with one or more birth parents with asthma (OR = 2.1, 95% CI 1.4-3.1); current wheeze was less common in those with older children living in the same household (for 2 or more older children in the same household, OR = 0.5, 95% CI 0.2-1.0). In a small nested case-control study it was found that current wheeze was more common in those with high levels of IgE (OR = 6.4, 95% CI 1.3-36.4) or low levels of selenium (OR = 3.1, 95% CI 0.9-11.8) in stored serum collected 8 years previously. There was no difference in the proportions with current wheeze, or with diagnosed asthma between Maori and European children, but Maori children were more likely to have current frequent nocturnal wheeze (OR = 2.2, 95% CI 1.0-5.1), current severe wheeze (OR = 1.8, 95% CI 0.8-3.7) or to have been admitted to hospital with asthma (OR = 2.4, 95% CI 1.2-4.8). Passive exposure to tobacco smoke was more common among Maori children, but this only partially accounted for the greater asthma severity in Maori children, and the lower prescribing of prophylactic medications in this group may also have contributed. CONCLUSIONS Multiple factors were associated with asthma symptoms in children in this age-group, including a family history of asthma, male gender, environmental tobacco smoke, environmental allergen exposure, atopy, and low selenium status. Further studies are required to assess the relative contributions of these factors to the prevalence of asthma in New Zealand.

Exposure to magnetic fields among electrical workers in relation to leukemia risk in Los Angeles County.

Abstract: To address the hypotheses that electrical workers are exposed to higher magnetic fields and are at higher risk of leukemia than nonelectrical workers, we performed a registry-based case-control study among men aged 20-64 years with known occupation who were diagnosed with cancer in Los Angeles County between 1972 and 1990. Controls were men with cancers other than those of the central nervous system or leukemia. Magnetic field measurements on workers in each electrical occupation and in a random sample of occupations presumed to be nonelectrical were used to estimate magnetic field exposures for each occupation. Among men in electrical occupations, 121 leukemias were diagnosed. With the exception of electrical engineers, magnetic field exposures were higher among workers in electrical occupations than in nonelectrical occupations. A weakly positive trend in leukemia risk across average occupational magnetic field exposure was observed (odds ratio [OR] per 10 milligauss increase in average magnetic field = 1.2, 95% confidence interval [CI] 1.0-1.5). A slightly stronger association was observed for chronic myloid leukemia, although only 28 cases occurred among electrical workers (OR 10 milligauss increase = 1.6, 95% CI = 1.2-2.0). The results were not materially altered by adjustment for exposure to several agents known or suspected to cause leukemia. Although not conclusive, these results are consistent with findings from studies based on job title alone that electrical workers may be at slightly increased risk of leukemia.

The self reported prevalence of asthma symptoms amongst adult New Zealanders.

Abstract: Aims To examine the prevalence of asthma symptoms in a random population sample of New Zealand adults aged 20-44 years drawn from the general and Maori electoral rolls as phase I of an international study of asthma prevalence Methods Subjects aged 20-44 years in Auckland, Hawkes Bay, Wellington and Christchurch, were selected randomly from the electoral rolls and sent a one page screening questionnaire, asking about respiratory symptoms, asthma attacks and asthma treatment They were also asked to record their ethnic affiliation Nonresponders were subsequently sent two written reminders followed by a telephone questionnaire where possible Results A response rate of 84% was achieved The study found a high prevalence of asthma symptoms, with 26% reporting wheezing in the last year, 8% experiencing an attack of asthma in the last year and 9% currently using asthma medication Females were more likely to have had wheezing in the last year (266%) and be on treatment for asthma (98%) compared with males (247% and 75% respectively) Small regional differences were found with more reported symptoms and asthma treatment in Wellington and Christchurch, compared with Auckland and Hawkes Bay Maori were more frequently symptomatic (352%) than nonPolynesian (248%) but were no more likely to report an attack of asthma (Maori 90%, nonPolynesian 77%) or be currently receiving asthma treatment (Maori 100%, nonPolynesian 86%) Asthma symptoms tended to decline with age in non Maori but increased with age in Maori Adjustment of prevalence rates by two independent methods suggests that nonresponse bias has not significantly inflated these rates Conclusions The symptoms of asthma and their treatment are common in young New Zealanders, affecting one in three Maori and one in four nonMaori One in ten of this adult population currently receive asthma treatment

Confounding by severity does not explain the association between fenoterol and asthma death

Abstract: Summary. Three recent case-control studies from New Zealand, and one from Saskatchewan, Canada, have found that fenoterol increases the risk of death in patients with severe asthma. It has been suggested that these findings may be due to confounding by severity, if fenoterol was selectively prescribed to more severe asthmatics. This ‘confounding by severity’ hypothesis has now been investigated in further analyses of data from the New Zealand case-control studies. This analysis found that among patients whose asthma was severe enough to require hospital admission (the population in whom the case-control studies were conducted), fenoterol was not preferentially prescribed to the more severe asthmatics. There was greater co-prescribing of other drugs with fenoterol (compared with salbutamol) during the later years of the epidemic, but these differences did not explain the excess risk associated with fenoterol, and there was little evidence of greater co-prescribing during the earlier years of the New Zealand epidemic of asthma deaths. There was no association between the prescription of fenoterol and markers of acute asthma severity or psychosocial problems. Patients were not selectively changed to fenoterol as a result of a severe attack resulting in a hospital admission. Most importantly, in the case-control studies of asthma deaths, the inhaled fenoterol relative risk increased when the analysis was restricted to sub-groups defined by markers of chronic asthma severity; whereas the relative risk would have decreased towards 1.0 in these sub-group analyses if the overall elevated risk for fenoterol was due to confounding by severity. We conclude that in patients whose asthma is severe enough to require hospital admission, there is little evidence that fenoterol was selectively prescribed to the more severe patients and that the findings in the most severe sub-groups effectively exclude the ‘confounding by severity’ hypothesis as an explanation for the recent case-control findings.

Prescribed drug therapy and near-fatal asthma attacks.

Abstract: Inhaled fenoterol has been associated with an increased risk of death in severe asthmatics, when compared to other adrenoceptor agonists It is plausible that fenoterol may also increase the risk of near-fatal attacks We have conducted a case-control study to investigate this hypothesis The cases comprised Intensive Care Unit (ICU) admissions for asthma in the Wellington region during 1977-1988 For each of these cases, two age-matched controls were selected from asthma admissions to the same hospital during the same period For the 155 cases and 305 controls, information on prescribed drug therapy was collected from the hospital admission records The relative risk of a near-fatal asthma attack in patients prescribed inhaled fenoterol was 200 (95% confidence interval (CI) 135-297) An increased risk was also observed for oral theophylline (odds ratio (OR) = 188; 95% CI 126-279) For the 65 cases and 104 controls who had a previous admission for asthma in the previous 12 months, information relating to the previous admission was also collected; an increased risk was once again observed for inhaled fenoterol (OR = 218; 95% CI 110-433) and for oral theophylline (OR = 118; 95% CI 099-357) No other asthma drugs showed significantly increased risks Although the ICU admission cases had generally been prescribed more asthma drugs than the hospital admission controls, and appeared to have more severe asthma, it is possible that the findings reported here are influenced by confounding by severity We nevertheless estimate that our findings are consistent with the hypothesis that fenoterol increases the risk of near-fatal asthma attacks, and that they complement previous findings on fatal asthma attacks(ABSTRACT TRUNCATED AT 250 WORDS)

Occupational exposures to carcinogens in developing countries.

Abstract: There have been very few studies of exposure to occupational carcinogens in developing countries, and even fewer studies of the health consequences of such exposures. However, all industrial chemicals, occupations and industrial processes classified by the International Agency for Research on Cancer (IARC) as Group 1 or Group 2A (carcinogenic or possibly carcinogenic to humans) have been described in developing countries, and there is growing concern that the health impact of many chemicals used in the developing world has been underestimated. In all regions a very large workforce is employed in the construction industry, in which substantial exposure to asbestos may occur, and there has been a rapid increase in production in countries such as Brazil and India. There is, for instance, a similar pattern for tyre production with a large increase in production in developing countries in the 1980s. Thus, the number of workers in industries entailing a carcinogenic risk is increasing in developing countries, partly as a result of the transfer of hazardous industry from industrialized countries. There is much that could be achieved in the prevention of occupational cancer in developing countries, and there have been a number of successful initiatives. However, the greatest progress in the prevention of occupational cancer in developing countries is most likely to come from political and economic changes.

Beta-agonist use and death from asthma.

Abstract: To the Editor —We read with interest the meta-analysis of Mullen et al1of case-control studies of β-agonists and asthma death, and we are in agreement with its methodology and general conclusions The meta-analysis shows that the results of Spitzer et al2are significantly different from those reported by all other researchers, whereas the finding of our New Zealand case-control studies3-5are consistent with those of other researchers6,7Mullen et al1suggest that the findings of Spitzer et al2may be different because they focused on an older age-group An alternative explanation is that the findings of Spitzer et al2are inconsistent because of methodological flaws in the study Their study was based on patients who had received 10 or more prescriptions for one or more asthma drugs during a 10-year period, and patient medication was then assessed for the previous 12 months

Community-based a asthma c care: trial o of a a ""credit c card" a asthma s self-management p plan

Abstract: Although asthma self-management plans are widely recommended as essential in the long-term treatment of adult asthma, there have been few studies examining their use. Our objective was to assess the effect of a "credit card" adult asthma self-management plan in a community experiencing major health problems from asthma, by means of a before and after intervention trial of the efficacy of the "credit card" plan, when introduced through community-based asthma clinics. The participants were 69 Maori people with asthma. The "credit card" plan consisted of written guidelines for the self-management of asthma, based on self- assessment of asthma severity, printed on a plastic card. On one side, management guidelines were based on the interpretation of peak expiratory flow rate (PEFR) recordings, whilst the reverse side was based on symptoms. The outcome measures used were before and after comparison of markers of asthma morbidity and requirement for acute medical treatment; and a structured questionnaire assessing the acceptability and use of the credit card plan. Following the introduction of the plan, the mean PEFR increased from 347 to 389 l·min-1, the percentage of nights woken fell from 30.4 to 16.9%, and the number of days "out of action" fell from 3.8 to 1.7%. The requirements for acute medical treatment also fell during the intervention period. Most participants commented favourably on the content and usefulness of the plan. In the situation of worsening asthma, 28% of subjects found the peak flow side of the card most helpful, 7% the symptoms side, and 48% found both sides equally helpful. The credit card asthma self-management plan, when introduced in a programme of community-based clinics, is both an effective and acceptable system for self- managing asthma.