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Biomedical subjects

N Pearce

Publications and source records attributed to N Pearce.

At least 145 records · Page 8Linked to original sources
PubMed1990

Case-control study of prescribed fenoterol and death from asthma in New Zealand, 1977-81.

A previous New Zealand case-control study of asthma deaths in the 5-45 year age group during 1981-3 found that prescription of fenoterol (by metered dose inhaler) was associated with an increased risk of death in patients with severe asthma. One major criticism of this study was that drug data for the cases and controls came from different sources. A new case-control design has been used to evaluate the same hypothesis, with a different set of asthma deaths, the same source for drug information being used for both cases and controls. This depended on identifying deaths from asthma during 1977-81 from national mortality records, and ascertaining which patients from those who died had been admitted to a major hospital for asthma during the 12 months before death. The study was confined to this subgroup, which accounted for about 20% of all asthma deaths in the areas served by a major hospital. For each of the eligible patients who died four age matched controls were selected from patients admitted to hospital for asthma during the year that the death occurred who had also had an admission for asthma in the previous 12 months. For the 58 cases and 227 control subjects information on prescribed drugs was collected from the hospital records relating to the previous admission. The odds ratio of asthma death in patients prescribed inhaled fenoterol was 1.99 (95% confidence interval 1.12-3.55, p = 0.02). As in the previous study, subgroups defined by markers of chronic asthma severity were also considered. The inhaled fenoterol odds ratio was 2.98 (95% CI 1.15-7.70, p = 0.02) in patients prescribed three or more categories of asthma drugs, 3.91 (95% CI 1.79-8.54, p less than 0.01) in patients with a previous admission for asthma in the past 12 months, and 5.83 (95% CI 1.62-21.0, p = 0.01) in patients prescribed oral corticosteroids at the time of admission. In patients with the most severe asthma (defined by a previous admission for asthma during the past 12 months and prescribed oral corticosteroids at time of admission) the inhaled fenoterol odds ratio was 9.82 (95% CI 2.23-43.4, p less than 0.01). These findings add further support to the hypothesis that inhaled fenoterol increases the risk of death in patients with severe asthma.

Administration, Inhalation↗
PubMed1989

A New Zealand Cancer Registry-based study of cancer in wood workers.

Wood workers have been previously reported to be at higher risk for the development of cancers of certain sites, including the nasal cavity, paranasal sinuses, lung, stomach, and lymphatic and hemopoietic tissues. Wood work involves exposure to a variety of potential carcinogens, including wood dust itself, chemicals applied to the wood, and other carcinogenic agents that are associated with wood work. We report a series of case-control studies based on the New Zealand Cancer Registry. These studies involved 19,904 male patients registered with cancer from 1980 to 1984 who were 20 years of age or older at the time of registration. For each cancer site studied, the registrants for all other sites (except lung cancer) formed the control group. The following four cancer sites were found to be associated with wood work: lip, nasopharynx, lung, and liver. There was little evidence of increased risks for other cancer sites. Among wood workers, sawmillers experienced the highest risks for lung cancer (odds ratio, 1.76; 95% confidence interval, 1.23 to 2.52) and liver cancer (odds ratio, 3.55; 95% confidence interval, 1.09 to 0.14). Carpenters showed increased risks for lip cancer (odds ratio, 2.28; 95% confidence interval, 1.23 to 4.14) and lung cancer (odds ratio, 1.27; 95% confidence interval, 1.05 to 1.54). The increased risk of nasopharyngeal cancer was strongest for foresters and loggers (odds ratio, 6.02; 95% confidence interval, 1.01 to 28.41).

Adult↗
PubMed1989

Bladder cancer and occupational exposure to polycyclic aromatic hydrocarbons.

The association between occupational exposure to polycyclic aromatic hydrocarbons (PAH) and bladder cancer development was investigated in a population-based case-control study carried out in the Bormida valley, Italy. One hundred and twenty-one male cases and 342 male controls, matched age, were collected from local hospitals. Occupational exposure to PAH and aromatic amines (AA) was evaluated by means of a job exposure matrix, constructed specifically for this study. Subjects considered as sharing a "definite exposure to PAH" showed an increased risk even after adjustment for cigarette smoking and exposure to AA (OR = 2.14, 95% CL 0.82-5.60). No elevation in risk was found for the category "possible exposure to PAH" (OR = 1.05, 95% CL 0.45-2.44). The findings of this study are consistent with previous studies indicating PAH as a risk factor for bladder cancer. A possible residual confounding effect due to AA impurities is discussed.

Case-Control Studies↗
PubMed1989

Modes of hepatitis B virus transmission in New Zealand.

We review some of the current literature on modes of transmission of hepatitis B virus (HBV) and report a descriptive study of lifestyle practices of children in the eastern Bay of Plenty and east coast of New Zealand. We also report a small case-control study of possible HBV infection risk factors in a group of central North Island school children, with a hepatitis B surface antigen (HBsAg) seroprevalence of 1.5%, and an HBV immune seroprevalence of 16%. Toothbrush, bathtowel and bed sharing were found to be risk factors for HBV infection in this group. The primary mode of HBV transmission in New Zealand is currently unknown, although it appears that direct contact by parenteral means (through blood and sores) may be the most likely route of spread. Direct contact by non parenteral means, including sharing food contaminated with blood, may also be important. Environment-mediated spread may play a role, particularly as a means of spread between cuts and sores. Avenues for further research are also suggested.

Carrier State↗
PubMed1989

Prescribed fenoterol and death from asthma in New Zealand, 1981-83: case-control study.

A case-control study was conducted to examine the hypothesis that fenoterol by metered dose inhaler (MDI) increases the risk of death in patients with asthma. The case group comprised 117 patients aged 5-45 who died of asthma between August, 1981, and July, 1983. For each case, 4 controls, matched for age and ethnic group, were selected from asthma admissions to hospitals to which the cases themselves would have been admitted, had they survived. The relative risk of asthma death in patients prescribed fenoterol by MDI was 1.55 (95% CI 1.04-2.33, p = 0.03). The possibility of confounding or effect modification by severity was assessed by consideration of subgroups defined by markers of asthma severity. The fenoterol MDI relative risk was 2.21 (95% CI 1.26-3.88, p = 0.01) in patients prescribed three or more categories of asthma drugs, 2.16 (95% CI 1.14-4.11, p = 0.02) in patients with a hospital admission for asthma during the previous 12 months, and 6.45 (95% CI 2.72-15.3, p less than 0.01) in patients prescribed oral corticosteroids at time of death or admission. In the group of patients with the most severe asthma (defined by a hospital admission during the previous year and prescription of oral corticosteroids) the fenoterol MDI relative risk was 13.29 (95% CI 3.45-51.2, p less than 0.01). After adjustment for severity, no other asthma treatment commonly used in New Zealand seemed to be associated with an increased risk of asthma death. Not all sources of bias can be definitely excluded; however, when considered together with other epidemiological and experimental evidence, these findings are consistent with the hypothesis that use of fenoterol by MDI increases the risk of death in severe asthma.

Acute Disease↗
PubMed1989

Soft-tissue sarcoma, non-Hodgkin's lymphoma and other cancers in New Zealand forestry workers.

Several studies have suggested that forestry workers are at increased risk for certain types of cancer including soft-tissue sarcoma (STS) and non-Hodgkin's lymphoma (NHL). We now report a series of national case-control studies based on the New Zealand Cancer Registry (NZCR). These involved 19,904 male patients with cancer for the period 1980-1984 who were aged 20 years or more at the time of registration. For each cancer site, the registrations for the remaining sites formed the control group. Current or most recent occupational titles were coded. There was an increased risk for STS (OR = 3.24) in forestry workers which was confined to men under 60 years of age at registration. An elevation in risk for NHL (OR = 1.84) was due to an increase in risk for lymphosarcoma and reticulosarcoma (ICD 200) (OR = 3.18). Acute myeloid leukemia was also associated with forestry work, although the estimate of risk was imprecise (OR = 2.24). Among other cancer sites, an increase in risk of neoplasia of the upper gastro-intestinal tract (ICD 150, 151, 152) was demonstrated. Odds ratios were elevated for cancer of the esophagus (OR = 1.77), stomach (OR = 2.22), small intestine (OR = 5.22), gall-bladder (OR = 4.13) and pancreas (OR = 1.79), as well as for nasopharyngeal cancer (OR = 5.56). These increases in cancer risk were not present in sawmill workers in New Zealand during the same period. The factors responsible for the increased cancer risks in forestry workers remain unclear and require further study.

Adult↗
PubMed1989

Design and conduct of occupational epidemiology studies: I. Design aspects of cohort studies.

Cohort and case-control studies are two standard approaches for investigating the etiology of occupational diseases. This paper, which is the first of a four-part series, contains a review of the design features of occupational cohort studies. Topics discussed include the basic features of prospective and historical cohort studies, options for defining the cohort, disease incidence ascertainment, and considerations involved in planning an occupational cohort study. Subsequent papers in this series will focus on data analysis of occupational cohort studies and the design and analysis of occupational case-control studies.

Cohort Studies↗
PubMed1989

Design and conduct of occupational epidemiology studies: II. Analysis of cohort data.

This paper reviews strategies and statistical methods for analyzing data from occupational cohort studies. Emphasis is placed on the common methods for grouped data analysis involving external and internal comparison populations. Analysis procedures reviewed are standardized mortality ratio, standardized rate ratio, and Mantel-Haenszel techniques for estimating relative risks. Methods for control of confounding, assessment of effect modification, and allowance for disease latency are discussed. These concepts and procedures are illustrated with data from an historical cohort mortality study of workers from an asbestos textile plant.

Biometry↗
PubMed1989

Design and conduct of occupational epidemiology studies: III. Design aspects of case-control studies.

Currently available approaches for the design of occupational case-control studies are reviewed. An accompanying paper reviews methods of analysis. We commence by drawing a distinction between cohort-based and registry-based studies. Methods for selecting cases and controls are then reviewed, including cumulative incidence and incidence density sampling, matching, sources of controls, and issues in control selection. Finally, the advantages and disadvantages of the case-control approach are summarized.

Cohort Studies↗
PubMed1989

Design and conduct of occupational epidemiology studies: IV. The analysis of case-control data.

This paper reviews the basic methods of analysis of data from case-control studies. The standard analytic methods are outlined first for a single stratum. The discussion is then extended to stratified analysis, multiple exposure levels, and analyses allowing for disease induction and latency periods. Finally, logistic regression is discussed as an extension of the more basic forms of analysis. The methods are illustrated with data from a study of lung cancer among asbestos textile plant workers.

Biometry↗