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Biomedical subjects

N Pearce

Publications and source records attributed to N Pearce.

At least 55 records · Page 3Linked to original sources
PubMed1990

Follow up of New Zealand participants in British atmospheric nuclear weapons tests in the Pacific.

OBJECTIVE: To study the health of Royal New Zealand Navy personnel who participated in atmospheric nuclear weapons tests conducted by the United Kingdom at Malden Island and Christmas Island in 1957 and 1958. DESIGN: Blinded, controlled follow up of up to 30 years. SETTING: New Zealand. SUBJECTS: 528 Men known to have participated in the tests and a control group of 1504 men who were in the Royal New Zealand Navy during the same period but did not participate in the tests. MAIN OUTCOME MEASURES: Mortality and incidence of cancer. RESULTS: Follow up for the period 1957-87 was 94% complete in test participants and 91% complete in the controls. There were 70 deaths among test participants and 179 deaths among controls, yielding a relative risk of 1.08 (90% confidence interval 0.85 to 1.38, p = 0.29). The relative risk of death from causes other than cancer was 0.96 (0.71 to 1.29, p = 0.59) whereas the relative risk of death from cancer was 1.38 (0.90 to 2.10, p = 0.09) and of the incidence of cancer was 1.12 (0.78 to 1.60, p = 0.29). For cancers other than haematological malignancies the relative risk was 1.14 (0.69 to 1.83, p = 0.31) for mortality and 1.01 (0.67 to 1.50, p = 0.48) for incidence. There were seven deaths from haematological cancers among test participants (relative risk 3.25, 90% confidence interval 1.12 to 9.64, p = 0.02), including four leukaemias (5.58, 1.04 to 41.6, p = 0.03). The relative risk for incidence of haematological cancers was 1.94 (0.74 to 4.84, p = 0.10) and that for leukaemia was 5.51 (1.03 to 41.1, p = 0.03). There were no cases of multiple myeloma in the test participants during the follow up period, but the expected number was only 0.3. CONCLUSIONS: Although the numbers are small, the findings for leukaemia are similar to those for British participants in the nuclear weapons test programme. Some leukaemias, and possibly some other haematological cancers, may have resulted from participation in this programme. There is little evidence of an increased risk for non-haematological cancers, and there is no evidence of an increased risk for causes of death other than cancer.

Cause of Death↗
PubMed1990

Epidemiologic studies of cancer in agricultural workers.

The incidence of cancer in agricultural workers is generally low, in part due to the low prevalence of cigarette smoking in this group. However, agricultural workers have elevated risks for several specific cancer types including leukemia, Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, and cancers of the lip, stomach, prostate, brain, and connective tissue. Two major groups of risk factors have been proposed as causes of hematologic malignancies in agricultural workers. The first group includes various agricultural chemicals. In particular, several studies have found increased risks of malignant lymphoma and soft tissue sarcoma in persons exposed to phenoxy herbicides. However, the evidence is inconsistent and there is a wide variation in relative risk estimates. The second group of risk factors includes various animal viruses. There is currently little evidence concerning the zoonotic nature or human carcinogenicity of these viruses. However, leads have been suggested by recent evidence of increased risks of hematologic malignancies in abattoir workers, veterinarians, and meat inspectors. A third hypothesis, for which little evidence is currently available, is that agricultural work may involve prolonged antigenic stimulus leading to lymphoproliferation. The factors responsible for the increased risks for cancers other than hematologic malignancies are not well understood but may also involve exposure to chemicals or viruses.

Abattoirs↗
PubMed1990

The pulmonary and extrapulmonary effects of inhaled beta-agonists in patients with asthma.

The cardiovascular, respiratory, and hypokalemic effects of repeated inhalation of fenoterol, albuterol, and isoproterenol were compared in 12 subjects with stable asthma according to a double-blind, crossover design. Ipratropium bromide served as a control providing bronchodilatation without extrapulmonary effects. Subjects inhaled the beta-agonists on an equal-weight basis (400 micrograms) at 0, 30, 40, and 45 minutes. Measurements of heart rate, blood pressure, total electromechanical systole (measure of inotropic activity), preejection period, QTc interval, plasma potassium levels, and forced expiratory volume in 1 second were made 5 minutes after each dose and again at 60 and 75 minutes. There were no differences in the bronchodilating effect between the beta-agonists. However, both fenoterol and isoproterenol resulted in greater positive inotropic stimulation than did albuterol, and fenoterol caused a greater fall in plasma potassium levels than did the other beta-agonists.

Adolescent↗
PubMed1990

White swans, black ravens, and lame ducks: necessary and sufficient causes in epidemiology.

Several authors have used Popper's "white swan" example to support arguments for a falsificationist approach to epidemiology. The statement "all swans are white" cannot be verified by finding even a large number of white swans, but can be falsified by finding a single black swan. An analogous epidemiologic example that has been proposed is the hypothesis that a particular virus is a necessary cause of acquired immunodeficiency syndrome (AIDS). Such examples, however, have little relevance to science since scientific theories are not generalizations of facts; rather, they involve an understanding of the underlying processes that cause certain facts to occur. Furthermore, the "white swan" example is particularly inapplicable to epidemiology, since most factors of scientific or public health importance are neither necessary nor sufficient causes of disease. Nevertheless, epidemiologic research has achieved success in the understanding and prevention of disease. These points are exemplified by applying Rothman's model of causal constellations, which provides a conceptual basis for the development of epidemiologic theories.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Cancer risks in painters: study based on the New Zealand Cancer Registry.

Painters are exposed to a range of complex chemical mixtures which include organic solvents and dye products with known carcinogenic and mutagenic potential. Trade painters or those manufacturing paints and coatings have increased rates of non-malignant diseases and cancers; including lung cancer, acute leukaemia, bladder cancer, and cancers of the oesophagus, larynx, biliary system, liver, skin, and large bowel. A series of case-control studies of painters, based on the New Zealand Cancer Registry, are presented. These concerned 19,904 male patients registered for the period 1980-4 who were aged 20 or older at the time of registration. For each cancer site studied, the registrants for all other cancer sites formed the control group. Three cancer sites were associated with work as a painter--namely, bladder tumours (odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.00-2.31), kidney and other urothelial tumours (OR 1.45, 95% CI 0.85-2.50), and multiple myeloma (OR 1.95, 95%, CI 1.05-3.65). Risks for multiple myeloma were greater among car or spray painters and signwriters (OR 2.81) compared with construction and general painters (OR 1.80). No increased risk was found for leukaemia or for respiratory, biliary, skin, or gastrointestinal cancers.

Adult↗
PubMed1990

Reduced selenium in asthmatic subjects in New Zealand.

Selenium is an essential component of glutathione peroxidase, an enzyme that helps protect cells against oxidation damage and modulates the lipoxygenase pathway of arachidonic acid metabolism. Low selenium concentrations might therefore influence the inflammatory process in asthma by reducing the activity of glutathione peroxidase. Whole blood and plasma selenium concentrations and glutathione peroxidase activity have been measured in 56 asthmatic patients and 59 non-asthmatic control subjects in New Zealand, a country with a low dietary selenium intake and a high prevalence of asthma. When compared with control subjects the asthmatic patients had lower values for whole blood selenium concentrations (-4.9, 95% confidence interval -10.2 to 0.4 ng/ml) and glutathione peroxidase activity (-3.3, 95% CI -5.8 to -0.8 units/g Hb). There was a 1.9 and 5.8 fold increased risk of asthma in subjects with the lowest range of whole blood selenium concentration and glutathione peroxidase activity respectively (95% CI 0.6 to 5.6 and 1.6 to 21.2). Levels were lower in patients and control subjects without an atopic predisposition, but were not affected by prednisone use. Similar differences between the asthmatic and control subjects were not observed for selenium concentration or glutathione peroxidase activity measured in plasma, which reflects short term rather than long term selenium content. These findings are consistent with the hypothesis that low selenium concentrations may have a role in the pathogenesis of asthma in New Zealand.

Adolescent↗
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↗