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Biomedical subjects

T Slater

Publications and source records attributed to T Slater.

At least 19 recordsLinked to original sources
PubMed2006

Pine dust, atopy and lung function: A cross-sectional study in sawmill workers.

An increased risk of asthma symptoms has previously been shown in 772 pine sawmill workers. The aim of the current study was to assess the association between dust exposure, lung function and atopy. Subjects with (n = 59) and without (n = 167) asthma symptoms were randomly selected from the previous survey. Lung function and atopy were determined using spirometry and skin-prick tests, respectively. Inhalable dust levels were measured on the same day. The geometric mean dust concentration was 0.52 mg x m(-3). Exposure to dry but not to green dust was associated with asthma symptoms. Green dust was associated with atopic sensitisation, particularly against outdoor allergens; no association was found for dry dust. Forced vital capacity, forced expiratory volume in one second and peak expiratory flow were significantly lower in workers exposed to high levels of green dust (-350 mL, -260 mL and -860 mL x s(-1), respectively) and dry dust (-230 mL, -190 mL and -850 mL x s(-1), respectively). These associations were observed both in subjects with and without asthma symptoms. No associations with cross-shift changes in lung function were found. Exposure to green pine sawdust may be a risk factor for atopy. Both green and dry dust were associated with obstructive as well as restrictive pulmonary effects.

Adult↗
PubMed2001

Asthma and other respiratory symptoms in New Zealand pine processing sawmill workers.

BACKGROUND: To study respiratory symptoms in pine sawmill workers. METHODS: A respiratory health questionnaire was administered to 772 pine sawmill workers and the association between symptoms and job-title-based exposure was studied. RESULTS: Asthma in exposed workers (18%, n = 704) was more common than in the general population (12.1%, n = 592; adjusted OR (95% CI): 1.6 (1.1-2.3)). Asthma was also more common in the low exposure group (15.6%, n = 294) and high exposure groups (high exposure to 'green dust'; 20.4%, n = 212 and high exposure to 'dry dust'; 18.8%, n = 198) than in the non-exposed workers (9.2%, n = 65). Adjusted odds ratios were 1.9 (0.7-4.9), 2.7 (0.9-7.6), and 2.1 (0.8-5.7), respectively. Adjusted odds ratios for symptoms of cough were 2.7 (1.2-6.5) for the low, 5.2 (2.1-13.0) for the high 'green dust' and 3.3 (1.4-7.9) for the high 'dry dust' exposure groups. Moreover, eye and nose irritations were significantly more prevalent in the high and low exposure groups. CONCLUSIONS: Working in pine sawmilling is associated with an increased prevalence of asthma and cough symptoms and eye and nose irritation.

Adult↗
PubMed2001

A case-control study of risk factors for asthma in New Zealand children.

OBJECTIVE: As in other English-speaking countries, asthma is a major and increasing health problem in New Zealand. This study examined the risk factors for asthma in children aged 7-9. METHODS: Cases and controls were randomly selected from participants in the Wellington arm of the International Study of Asthma and Allergies in Childhood (ISAAC). Cases were children with a previous diagnosis of asthma and current medication use (n=233), and controls were children with no history of wheezing and no diagnosis of asthma (n=241). RESULTS: After controlling for confounders, factors significantly associated with asthma were maternal (OR=3.36, 95% CI 1.88-5.99) and paternal asthma (OR-2.67, 95% CI 1.42-5.02), and male sex (OR=1.81, 95% CI 1.17-2.81). Children from social classes 5 and 6 or with unemployed parents (OR=2.32, 95% CI 1.22-4.44) were significantly more likely to have asthma than children in social classes 1 and 2. There was no significant association between having polio vaccination (OR=2.48, 95% CI 0.83-7.41), hepatitis B vaccination (OR=0.66, 95% CI 0.42-1.04) or measles/mumps/rubella vaccination (OR=1.43, 95% CI 0.85-2.41) and asthma. CONCLUSIONS: This study has confirmed the associations of family history and lower socio-economic status with current asthma in 7-9 year old children. The role of vaccinations requires further research.

Asthma↗
PubMed2000

Changes in work practice after a respiratory health survey among welders in New Zealand.

AIMS: To assess changes in work practice among eight New Zealand engineering sites, following a study of occupational respiratory symptoms in welders two years previously. METHODS: In 1996, we found that an acute decrease in lung function was more common in welders working without local exhaust ventilation. Findings were reported back to management, study participants and the media. Two years later we re-visited the eight welding sites. RESULTS: Of the eight engineering sites, two had local exhaust ventilation present in both Study 1 and Study 2, one site had installed local exhaust ventilation in part of the site since Study 1 and one site had moved to larger premises. The remaining four sites had no exhaust ventilation or change to the workplace between studies. Five welders (12.8%) used respiratory protection in both Study 1 and Study 2, seven welders (18%) used respiratory protection in Study 1 but not Study 2, four welders (10.3%) did not have respiratory protection in Study 1 but did in Study 2 and nine welders (23.1%) did not use respiratory protection at all in Study 1 or Study 2. CONCLUSION: Further effort is required to ensure that such studies lead to significant improvements in the work environment.

Air Pollutants, Occupational↗
PubMed2000

Asthma morbidity 6 yrs after an effective asthma self-management programme in a Maori community.

A 6-month Maori community-based asthma self-management programme, involving a "credit card" asthma self-management plan, has previously been shown to be an effective and acceptable system for reducing asthma morbidity. The effectiveness of the asthma self-management programme and participants' self-management behaviour was assessed 6 yrs after the formal end of the programme. Participants were surveyed at the time of enrollment, and 1, 2, and 6 yrs after completing the programme. In each survey, participants were questioned on markers of asthma morbidity and use of medical services during the previous 12 months. Self-management behaviour was assessed using a questionnaire at 2 years and 6 yrs. Of the 69 original participants, 47 (68%) were surveyed after 6 yrs. They generally had reduced severe asthma morbidity and emergency use of health services from baseline. In particular, the proportion who had an emergency visit to a general practitioner had decreased from 41% to 18% (p=0.02). However, the percentage of nights woken due to asthma had returned to preintervention levels, and the proportion of participants taking prescribed regular inhaled steroid had decreased from 91% to 53% (p<0.001). Compared with 2 yrs after completion of the asthma programme, self-management behaviour had also deteriorated, with 29% versus 73% (p<0.001) using their peak flow meter daily when their asthma was "getting bad" and 41% versus 86% (p<0.001) using the "credit card" plan to increase the amount of inhaled steroids in the last year. Although the programme participants were still experiencing reduced morbidity from their asthma 6 yrs after the end of the self-management programme, the benefits were less than those observed at 2 yrs. These findings suggest that under-recognition and under-treatment of asthma with appropriate amounts of inhaled steroids is a major factor contributing to asthma morbidity in this indigenous rural community. To obtain enduring benefits from a self-management system of care continued reinforcement of self-management skills seems to be an essential component of any follow-up.

Adult↗
PubMed2000

Occupational respiratory symptoms in New Zealand hairdressers.

BACKGROUND: A study of occupational respiratory symptoms in hairdressers was carried out in 26 salons in New Zealand. METHODS: A questionnaire was administered to 100 hairdressers and 106 office and shop workers, recording respiratory symptoms, demographic data, and smoking habits. Pulmonary function was measured before each shift. RESULTS: Hairdressers had a higher prevalence of asthma symptoms, diagnosed asthma, and asthma attacks in the previous 12 months, but these differences reduced markedly when adjusted for age, gender and smoking. Hairdressers had a significantly lower pulmonary function, even after adjustment for smoking, but this difference was entirely due to differences between hairdressers and office workers and there were no such differences between hairdressers and shop workers. CONCLUSIONS: The excess symptom prevalence in hairdressers was largely due to the high smoking rates. Mean pulmonary function was lower in hairdressers but this finding requires further study.

Adolescent↗
PubMed1999

Asthma and allergy in New Zealand farmers.

AIMS: To examine the prevalence of symptoms of asthma and allergy in different farming groups in New Zealand. METHODS: A postal questionnaire was sent to a random sample of 2,500 farmers throughout New Zealand. RESULTS: The response rate was 77% (1,706 of 2,203 eligibles). The 12-month period prevalence of current asthma was 11.8% overall, compared with 15% in the general population. Asthma prevalence was higher for horse breeders/groomers (16.5%), pig farmers (18.2%), poultry farmers (17.4%), and those working with oats (17.4%). Asthma was also significantly elevated among those working with cleaning powders (14.7%). Women were more likely to report current asthma than were men (OR 1.8, 95% CI 1.3-2.5). Hay fever was significantly higher in deer and crop farmers, and farmers working with horses and goats; eczema was higher for goat and deer farmers. CONCLUSIONS: The lower overall prevalence of asthma in farmers may be due to the healthy worker effect. Among farmers, the types of farming associated with an elevated prevalence of asthma and allergy in New Zealand are deer and goat farming, working with horses, poultry, pigs, and crop farming. Females reported more current asthma than males.

Adolescent↗
PubMed1999

Indoor environment, atopy and the risk of the asthma in children in New Zealand.

The objective of this study was to examine the relationship between the indoor environment, atopy and asthma in 7-9-year-old children. Cases and controls were randomly selected from children who participated in the International Study of Asthma and Allergies in Childhood (ISAAC) in Wellington, New Zealand. Cases were children with a previous diagnosis of asthma and current medication use (n = 233) and controls were children with no history of wheezing and no diagnosis of asthma (n = 241). Information was recorded about the indoor environment during the first year of life and currently. Dust was sampled from floors and beds and Der p 1 and Fel d 1 measured using enzyme-linked immunosorbent assays. Skin-prick tests were performed with eight common allergens. Sensitization to Dermatophagoides farinae (OR = 3.19; 95% CI 1.74-5.84), Dermatophagoides pteronyssinus (OR = 2.06; 95% CI 1.16-3.65) and cat (OR = 3.89; 95% CI 1.06-14.30) were independently associated with current asthma. The use of a sheepskin in the first year of life (OR = 1.91; 95% CI 1.11-3.33) was also independently associated with current asthma but current Der p 1 levels showed no association with current asthma. Exposures in early life may be more important than current exposures in determining asthma at age 7-9 years. Prospective studies are needed in New Zealand to determine the relative importance of early life exposures to Der p 1 and other risk factors for asthma.

Air Pollution, Indoor↗
PubMed1999

Long-term benefits for Mäori of an asthma self-management program in a Mäori community which takes a partnership approach.

BACKGROUND: In 1991, an intervention trial of the efficacy of an asthma self-management plan was carried out in partnership with a rural Mäori community. The program relied on Mäori community health workers and other health professionals working in partnership, was delivered through clinics in traditional Mäori community centres and Mäori processes were followed throughout. The plan was shown to be effective in reducing asthma morbidity. OBJECTIVE: To assess whether the long-term benefits of the program extent beyond reduced asthma morbidity and the extent to which any additional benefits may be related to the partnership approach employed by the program. METHOD: Forty-seven (68%) of the original program participants were surveyed in August 1997. Participants were questioned on the program's impact in areas such as cultural development, health service access and lifestyle. RESULTS: In addition to the improvements in asthma morbidity, the program was found to have four key benefits: cultural affirmation; improved access to other health services; a greater sense of control for participants; and positive impacts on the extended family. CONCLUSIONS: The program's benefits extended beyond reduced asthma morbidity and were not due simply to the introduction of the asthma self-management plan but also to the partnership approach employed by the program. IMPLICATIONS: The study provides support for providing public health services for indigenous communities that take a partnership approach, utilise community expertise and are delivered in a way that is consistent with each community's cultural processes.

Adult↗
PubMed1999

Two year follow up of pulmonary function values among welders in New Zealand.

OBJECTIVES: To examine whether welding is a risk factor for an accelerated decline in pulmonary function. METHODS: 2 Year follow up of pulmonary function and respiratory symptoms among 54 welders and 38 non-welders in eight New Zealand welding sites. RESULTS: There were no significant differences in age, height, smoking habits, ethnicity, or total time in industrial work between welders and non-welders. No overall differences were noted in the changes of pulmonary function variables between the two study groups. However, when the comparison was restricted to smokers, welders had a significantly greater (p = 0.02) annual decline (88.8 ml) in FEV1 than non-welders, who had a slight non-significant annual increase (34.2 ml). Also, welders without respiratory protection or local exhaust ventilation while welding had a greater annual decline both in forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) than welders with protection (p = 0.001 and 0.04, respectively). Among welders a significant association was found between the acute across shift change and the annual decline in FEV1. Chronic bronchitis was more common among welders (24%) than non-welders (5%). Only one welder (2%) but eight non-welders (21%) reported having asthma. CONCLUSIONS: Welders who smoked and welders working without local exhaust ventilation or respiratory protection have an increased risk of accelerated decline in FEV1.

Adult↗
PubMed1998

Chronic bronchitis, work related respiratory symptoms, and pulmonary function in welders in New Zealand.

OBJECTIVES: A cross sectional study of respiratory symptoms and lung function in welders was performed at eight New Zealand welding sites: 62 current welders and 75 non-welders participated. METHODS: A questionnaire was administered to record demographic data, smoking habit, and current respiratory symptoms. Current and previous welding exposures were recorded to calculate a total lifetime welding fume exposure index. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) were measured before the start of the shift. RESULTS: There were no significant differences in ethnicity, smoking habits, or years of work experience between welders and non-welders. Symptoms of chronic bronchitis were more common in current welders (11.3%) than in non-welders (5.0%). Of those workers with a cumulative exposure index to welding fume > or = 10 years, 16.7% reported symptoms of chronic bronchitis compared with 4.7% of those with a cumulative exposure index < 4 years (odds ratio (OR) 4.1, 95% confidence interval (95% CI) 0.90 to 17.6). Workers with chronic bronchitis had significantly lower measures of baseline PEF (p = 0.008) and FEV/FVC ratio (p = 0.001) than workers without chronic bronchitis. Multivariate analysis showed that current smoking (OR 9.3, 1.0 to 86.9) and total exposure index to welding fumes > 10 years (OR 9.5, 1.3 to 71.9) were independent risk factors for chronic bronchitis. The report of any work related respiratory symptom was more prevalent in welders (30.7%) than non-welders (15.0%) and workers with these symptoms had significantly lower FEV, (p = 0.004) and FVC (p = 0.04) values. Multivariate analysis identified a high proportion of time spent welding in confined spaces as the main risk factor for reporting these symptoms (OR 2.8, 1.0 to 8.3). CONCLUSION: This study has documented a high prevalence of symptoms of chronic bronchitis and other work related respiratory symptoms in current welders. Also, workers with chronic bronchitis had reduced PEF and FEV/FVC compared with those without chronic bronchitis. These symptoms related both to cigarette smoking and a measure of lifetime exposure to welding fume.

Adolescent↗
PubMed1998

Prevalence of adult asthma symptoms in relation to climate in New Zealand.

We conducted an ecological study linking prevalence of adult asthma symptoms with climate in the 93 New Zealand general electorates. For each electorate, the 12-month period prevalence of self-reported asthma symptoms was determined using a random sample of adults aged 20-44 on the 1991 New Zealand electoral roll. Long-term average climate was estimated using a national climate database and a geographic information system. Asthma prevalence was calculated within quartiles of the exposure variables. Independent effects of climate variables were assessed using linear regression models, with adjustment for confounding by climate, social deprivation, and geographic variables. There was a statistically significant association between asthma prevalence and mean temperature, with the lowest quartile of mean temperature having an approximately 2% lower asthma prevalence. After adjusting for confounding, there was a monotonic increase in asthma prevalence within quartiles of temperature. The results of this study are in agreement with other research suggesting a lower prevalence of asthma at low temperatures. Although on short (day-to-day) time scales, low temperatures may have a direct effect resulting in acute exacerbations of asthma symptoms, warmer average temperatures are associated with increased asthma prevalence. The reasons for this are unclear, although it is possible that on longer term (annual) time scales, higher temperatures are associated with higher levels of allergen exposure.

Adult↗
PubMed1997

Respiratory questionnaire responses: how they change with time.

AIM: Responses to respiratory questionnaires are often used to identify individuals with asthma symptoms and may also be used to identify asymptomatic individuals. This study investigates the repeat responses over four years to such a questionnaire in a population of adult New Zealanders. METHODS: Seven hundred and twenty three asthmatics were sent two almost identical questionnaires in three areas of New Zealand, separated by approximately four years. All of them had answered yes to at least one of the three questions under study in the first survey. RESULTS: Following the second asthma questionnaire only 487 (67.4%) answered yes to at least one of the survey questions. Similarly, 51.1% of those who had reported having nocturnal shortness of breath in the first survey did so in the second survey, 69.9% of those who reported having had an asthma attack in the first survey did so in the second survey, and finally 74.8% of those who reported using asthma medication in the first survey did so in the second survey. CONCLUSION: Even in a previously identified symptomatic asthmatic group, a large proportion did not report respiratory symptoms and asthma medication use four years later. This implies that the true prevalence pool of susceptibles is likely to be far greater than is identified in surveys of the 12-month period prevalence of asthma symptoms. This has implications not only for the design of epidemiological studies (e.g., it poses problems for the selection of a control group of non-asthmatics in prevalence case-control studies), but also for the planning of health services and educational programmes for people with asthma.

Adult↗
PubMed1997

Geographical variation in the prevalence of asthma symptoms in New Zealand.

AIMS: To examine geographical variations in the prevalence of asthma symptoms in a random population sample of New Zealand adults aged 20-44 years. METHODS: A one page asthma symptom questionnaire was sent to 31470 people aged 20-44 years. The questionnaire asked about respiratory symptoms, asthma attacks and asthma treatment. Those who had not responded after two reminder postcards were followed with a telephone call where possible. RESULTS: A response rate of 82% (25664) was achieved. The 12 month period prevalence of asthma (defined as woken by shortness of breath, or an attack of asthma in the past year, or current asthma medication) was 15.2% overall, but was higher in females (17.0%) than in males (13.2%); the prevalence was 22.1% in Maori, 20.6% in Pacific Islanders and 14.3% in non Polynesians. In North Island electorates, the highest age and ethinicity standardised prevalences were found in some of the electorates in the Auckland and Wellington urban regions although prevalence was also high in some rural electorates including Raglan (18.0%), Horowhenua (18.4%) and Wairarapa (18.4%); the lowest prevalences were found in other rural electorates including King Country (5.5%), Matamata (10.1%) and Rotorua (10.3%). In South Island electorates, the highest prevalences were found in some electorates in the Christchurch and Dunedin urban areas, and the lowest prevalences were again found in rural electorates including Clutha (11.3%), Rangiora (9.5%) and Wallace (9.4%). CONCLUSIONS: This study confirms the previously reported high frequency of asthma symptoms in New Zealand adults, with higher symptom prevalence in Maori and in women. It shows significant urban/rural differences, as well as marked differences in prevalence between various rural areas. The reasons for these patterns are unclear and require further study.

Adult↗
PubMed1997

Under the volcano: fire, ash and asthma?

AIMS: To investigate the prevalence of respiratory symptoms in known asthmatics, following exposure to airborne volcanic ash particles caused by the eruptions of Mount Ruapehu, New Zealand, commencing September 1995. METHOD: A one page postal questionnaire was sent to 1392 previously identified asthmatics 2 months after the first major eruption. RESULTS: Two hundred and thirty seven subjects had moved from the area, died or gone overseas since the original contact 4 years previously; therefore the target population was 1155 subjects of whom 361 lived in the exposed area and 794 in the nonexposed areas. The response rates were 246 (68.1%) in the exposed group and 477 (60.1%) in the nonexposed group making a total of 723 individuals. The prevalence of nocturnal shortness of breath in the last two months was 29.3% in the exposed group and 24.7% in the nonexposed (OR = 1.26, 95% CI; 0.83-1.78). Similarly 30.9% of the exposed group had an asthma attack in the last 2 months compared to 31.9% of the nonexposed group (OR = 0.96, 95% CI; 0.69-1.33). Finally, 48.4% of the exposed group used asthma medication in the 2 months following the eruption in comparison to 53% of the nonexposed group (OR = 0.83, 95%, CI; 0.61-1.12). CONCLUSIONS: The study showed no association between living in an area exposed to volcanic ash particles and either asthma symptoms or the use of asthma medication. There was a small but nonsignificant increase in nocturnal shortness of breath in the exposed group.

Acute Disease↗
PubMed1997

Further follow-up of New Zealand participants in United Kingdom atmospheric nuclear weapons tests in the Pacific.

We previously reported a study of deaths and cancer incidence in Royal New Zealand (RNZ) Navy personnel who participated in atmospheric nuclear weapons tests conducted by the United Kingdom in the Pacific in 1957-58. The study involved 528 men known to have participated in the tests, and a control group of 1,504 men who were in the RNZ Navy during the same period but were not involved in the tests. The original follow-up was carried out for the period 1957-87 with an observed increase in risk of leukemia and other hematologic cancers, but little or no increase of non-hematologic cancers or non-cancer deaths in test participants. Follow-up now has been extended for the period 1988-92. For the total follow-up period, there were 97 deaths in test participants and 256 deaths in controls, a relative risk (RR) of 1.1 (90 percent confidence interval [CI] = 0.9-1.3). The RR of death from causes other than cancer was 1.0 (CI = 0.8-1.3), whereas the RR of cancer death was 1.2 (CI = 0.8-1.7) and that of cancer incidence was 1.0 (CI = 0.8-1.4). For cancers other than hematologic malignancies, the RR was 1.0 (CI = 0.7-1.5) for mortality, and 1.0 (CI = 0.7-1.3) for incidence. However, there were eight deaths from hematologic cancers in test participants (RR = 3.8, CI = 1.4-10.8), including four leukemias (RR = 5.6, CI = 1.0-41.7). The RR for incidence of hematologic cancers was 1.9 (CI = 0.8-4.3), and that for leukemia was 5.6 (CI = 1.0-41.6). We concluded that the evidence is still consistent with the hypothesis that some leukemias and other hematologic cancers may have resulted from participation in the nuclear weapons test program, but the further follow-up strengthens the evidence that there is no increased risk for non-hematologic cancers or for causes of death other than cancer in the test participants.

Confidence Intervals↗
PubMed1997

Determinants of house dust mite allergen in homes in Wellington, New Zealand.

OBJECTIVES: To measure levels of the major Dermatophagoidespteronyssinus allergen (Der p 1) in homes in Wellington, New Zealand, and to examine factors which affect these levels. METHODS: As part of a study of risk factors for asthma among 474 8-10-year-old children, standard procedures were used to collect reservoir dust and to measure Der p 1 levels on the living room floor and child's bedroom floor and bedding. Der p 1 levels were analysed both as geometric mean microg/g of fine dust and as microg/m2. Questionnaires collected information about factors which might influence these levels, and an average relative humidity in the bed and on the bedroom floor was also measured. RESULTS: Similar geometric mean levels of Der p 1 were found at each floor site - 25.5 microg/g (95% CI: 22.8-28.5) in the living room and 26.4 microg/g (95% CI: 23.7-29.3) on the child's bedroom floor. The geometric mean level of Der p 1 in the child's bed was 46.6 microg/g (95% CI: 42.3-51.3). After controlling for possible confounders, geometric mean living room and bedroom floor Der p 1 levels were significantly higher in households with older carpet than households with no carpets or newer carpets, and higher in the autumn. Households with three or more children had higher levels of Der p 1 than households with fewer children. Bedding levels were significantly higher in beds with kapok or inner sprung mattresses, or wool underlays and at relative humidities above the mean (51%). CONCLUSION: The very high levels of house dust mite allergen (Der p 1) found in Wellington are likely to be due to a variety of life-style and climatic factors. However, the type and age of floor covering appears to be the single most important factor.

Allergens↗