Treatment of Paget's disease of bone: a survey of clinical practice in Australia.

Consensus guidelines for the treatment of Paget's disease of bone have been published, but it is not known how closely these reflect clinical practice. We conducted a multi-centre, stratified, retrospective review of case notes of 531 subjects treated for Paget's disease of bone between 2000 and 2005 in 29 Australian centres. The subjects received 1072 courses of bisphosphonate treatment (pamidronate 363, alendronate 324, risedronate 208, tiludronate 103, zoledronic acid 69, and etidronate 5). The most recent treatment received was oral therapy in 57% of patients (alendronate 29%, risedronate 24%, and tiludronate 4%) and intravenous in 43% (pamidronate 33%, and zoledronic acid 10%). For oral bisphosphonates, the percentages of courses which were at the recommended dosage and duration were: alendronate 33%, risedronate 60% and tiludronate 29%. Pamidronate was administered in a wide range of dosing schedules, most commonly 60 mg every 3 months (18%), 6 months (17%) or annually (12%), whereas zoledronic acid was mainly given as a 4 mg infusion (98%) as a single dose (52%) or annually (19%). Most clinicians reported taking into account symptoms, plasma alkaline phosphatase activity and anatomical location of disease in determining the need for treatment. Patient preference, intolerance of oral therapy and compliance were ranked highest in determining the choice between oral and intravenous therapy. We conclude that oral and intravenous bisphosphonate dosing regimens are both commonly used to treat Paget's disease of bone in Australia. Only a minority of courses of oral bisphosphonate treatment are at the recommended dosage and duration, and there is a lack of consensus on regimens for intravenous treatment.

Improving response rates to primary and supplementary questionnaires by changing response and instruction burden: cluster randomised trial.

OBJECTIVE: Supplementary questionnaires provide additional information from subgroups, but may have an attritional effect on response rates. We examined the effects of different instruction methods on response rates to a two-part questionnaire. METHODS: The ACT Kindergarten Health Survey comprises a health questionnaire for all school-entry children. A supplementary questionnaire targets children with respiratory symptoms. We cluster-randomised 109 schools in the ACT (4,494 children) to two instruction groups. Group 1 (instruction burden) had instructions to complete the supplementary questionnaire if certain questions in the primary questionnaire were answered. Group 2 (response burden) had instructions to complete both questionnaires irrespective of answers to the primary questionnaire. RESULTS: Instructing all respondents to complete both questionnaires regardless of eligibility resulted in a statistically significantly lower primary questionnaire response rate (82% vs. 87%), but a statistically significantly higher response rate to the supplementary questionnaire (99% vs. 91%). The net effect was a small overall gain (82% vs. 79%) for the response burden group. CONCLUSION: Increasing the response burden had a minor impact on response rate to the primary questionnaire, but increased the response rate for most items to the supplementary questionnaire. IMPLICATIONS: Large surveys may be broken into primary and supplementary questionnaires, if strategies to maximise response rates are used. Questionnaires may need to be modified to take into account the likely attrition on response to either questionnaire resulting from instruction and response burdens.

The relationship between low level nitrogen dioxide exposure and child lung function after cold air challenge.

BACKGROUND: Nitrogen dioxide (NO(2)) or home gas appliance use has been inconsistently associated with adverse respiratory outcomes in childhood. OBJECTIVES: (i) To examine the contribution of home gas appliance type and personal NO(2) exposure. (ii) To examine the relationship between NO(2) exposure and child lung function and respiratory history. (iii) To assess whether these relationships vary by house dust mite sensitization status. METHODS: A cross-sectional survey of 344 children (71% of the eligible group) with a mean age of 9.1 years from four randomly selected schools in the Australian Capital Territory from July to September 1999. Study measurements included a parental questionnaire, NO(2) exposure by passive gas samplers, skin prick testing for 10 aeroallergens and lung function at rest and after cold air challenge. RESULTS: Total NO(2) exposure was low with a mean concentration of 10.1 ppb. No associations were found between NO(2) exposure or gas appliance use and asthma, wheeze or baseline lung function. Personal NO(2) exposure was associated with a reduction in forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) after cold air challenge (adjusted difference - 0.12% (- 0.23% to - 0.01%) per 1 ppb increase). After exclusion of children who had home heating changed because of asthma, gas heater use was also significantly associated with a reduction in this measure (adjusted difference - 2.0% (- 3.7% to - 0.2%)). There was some evidence that these reductions were greater among the non-mite-sensitized children. CONCLUSIONS: The effect of low-level NO(2) exposure on these respiratory outcomes was not marked. The possible effect of low-level NO(2) exposure on non-specific bronchial reactivity requires confirmation. Future studies on NO(2) and respiratory health should include measures of house dust mite sensitization and bronchial hyper-responsiveness.

Asthma screening as part of a routine school health assessment in the Australian Capital Territory.

OBJECTIVE: To determine the feasibility and performance of a routine screen for childhood asthma in new entrants to primary school relative to diagnosis by a paediatrician. DESIGN: Cross-sectional study with a validation substudy. PARTICIPANTS AND SETTING: All 4539 new primary school entrants (mean age, 5.72 years; 95% CI, 5.71-5.74) in the Australian Capital Territory (ACT) in 1999; 180 of these children (73% of the 248 contacted) participated in the validation substudy. MAIN OUTCOME MEASURE: Performance of the screening test relative to a paediatrician's diagnosis of current asthma (defined as a history of wheeze suggestive of a clinical diagnosis of asthma within the past 12 months) based on history and examination. RESULTS: 3748 of the 4539 new primary school entrants (83%) returned completed asthma and respiratory questions. The screening test was positive in 38% of children. Estimated sensitivity was 92% (95% CI, 75%-99%); specificity, 76% (95% CI, 72%-80%); positive predictive value, 51% (95% CI, 41%-63%); negative predictive value, 98% (95% CI, 90%-100%); positive likelihood ratio, 3.8 (95% CI, 2.8-4.8); and negative likelihood ratio, 0.14 (95% CI, 0.02-0.33). CONCLUSIONS: It is feasible to conduct population screens for asthma that have good diagnostic test performance against a specialist paediatrician's diagnosis through school health programs. This approach could facilitate monitoring changes in asthma prevalence over time.

Bicycle helmet efficacy: a meta-analysis.

Bicycle helmet efficacy was quantified using a formal meta-analytic approach based on peer-reviewed studies. Only those studies with individual injury and helmet use data were included. Based on studies from several countries published in the period 1987-1998, the summary odds ratio estimate for efficacy is 0.40 (95% confidence interval 0.29, 0.55) for head injury, 0.42 (0.26, 0.67) for brain injury, 0.53 (0.39, 0.73) for facial injury and 0.27 (0.10, 0.71) for fatal injury. This indicates a statistically significant protective effect of helmets. Three studies provided neck injury results that were unfavourable to helmets with a summary estimate of 1.36 (1.00, 1.86), but this result may not be applicable to the lighter helmets currently in use. In conclusion, the evidence is clear that bicycle helmets prevent serious injury and even death. Despite this, the use of helmets is sub-optimal. Helmet use for all riders should be further encouraged to the extent that it is uniformly accepted and analogous to the use of seat belts by motor vehicle occupants.

Middle ear effusion: rate and risk factors in Australian children attending day care.

There have been no previous longitudinal studies of otitis media conducted in non-Aboriginal Australian children. This paper describes the rate and risk factors for middle ear effusion (MEE) in children attending day care in Darwin, Australia. A prospective cohort study of 252 children under 4 years was conducted in 9 day care centres over 12 fortnights between 24 March and 15 September 1997. Tympanometry was conducted fortnightly and multivariate analysis used to determine risk factors predicting MEE. The outcome of interest was the rate of type B tympanograms per child detected in either ear at fortnightly examinations. After adjusting for clustering by child, MEE was detected on average 4.4 times in 12 fortnights (37% of all examinations conducted). Risk factors associated with presence of effusion were younger age, a family history of ear infection, previous grommets (tympanostomy tubes), ethnicity and the day care centre attended. A history of wheeze appeared protective. These effects were modest (RR 0.57-1.70). Middle ear effusion is very common in children attending day care in Darwin. This has clinical importance, since MEE during early childhood may affect optimal hearing, learning and speech development. There is little scope for modification for many of the risk factors for MEE predicted by this model. Further study of the day care environment is warranted.

Cyanobacterial (blue-green algae) contamination in drinking water and perinatal outcomes.

OBJECTIVE: The aim of this ecological study was to examine the relationship between potential cyanobacterial exposure through drinking water during pregnancy and birth outcomes. METHOD: One hundred and fifty-six communities in South-Eastern Australia were involved, providing 32,700 singleton live newborn during the period 1992-94. Cyanobacterial occurrence and cell density (alert level) in drinking water sources during the first trimester, the total gestational period for premature births or limited to 36 weeks in term infants, and the last 12 weeks prior to preterm births or up to and including 36 weeks in term infants were used as estimates of exposure. RESULTS: There were statistically significant differences between the proportion of time during the first trimester with cyanobacterial occurrence and the percentage of births that were low birth weight (LBW) and very low birth rate (VLBW). Significant differences were also found among various categories of first trimester exposure based on average cell density and LBW, prematurity and congenital defects. However, the pattern of these results does not suggest a causal link to cyanobacteria. There were no clear dose-response relationships. Analyses based on exposure during the last 12 weeks and total gestation also showed no significant dose-response effects. CONCLUSION: The results of this study provide no clear evidence for an association between cyanobacterial contamination of drinking water sources and adverse pregnancy outcomes.

Postoperative prognosis in craniopharyngioma with respect to cardiovascular mortality, survival, and tumor recurrence.

Specific causes of death, survival, and recurrence rates were assessed in a cohort of 60 patients who had undergone surgery for craniopharyngioma between 1951 and 1988. Compared to the general population, the standardized mortality ratio (SMR) was increased [5.55; 95% confidence interval (CI), 3.68-8.22], and it was higher among females (SMR, 11.4) than males (SMR, 4.79). The risk of cardio- and cerebrovascular mortality (SMR, 3.21; 95% CI, 1.29-6.61) was also enhanced. The cumulative survival rates 10 and 15 yr after the initial operation were 68% (95% CI 54-78) and 59% (95% CI 30-63), respectively. A multivariate survival analysis adjusting for age showed a protective effect of radiotherapy (hazard ratio, 0.3; 95% CI, 0.1-0.8) and an increased risk of death after recurrence (hazard ratio, 4.4; 95% CI, 1.4-14), but no obvious effect of radicality at surgery. However, when patients who had died within 6 months after surgery were excluded, no significant protective effect of radiotherapy remained. The cumulative frequency of recurrence after 10 yr was 33% (95% CI, 22-48%), and that after 15 yr was 40% (95% CI, 28-56%). The incidence of recurrence did not differ significantly with respect to age, radicality at surgery, or postoperative radiotherapy. The determinants for long term outcome in patients with craniopharyngioma are interrelated in a complex way, which calls for strict selection criteria in follow-up studies and the use of multivariate statistical models.

Mixed feelings: satisfaction and disillusionment among Australian GPs.

BACKGROUND AND AIMS: Medical practitioners' satisfaction with their work impacts on quality of care for their patients and on their own sense of fulfillment. Reforms introduced in the early 1990s into Australian general practice have led to concerns over the morale of GPs. This study examines satisfaction and dissatisfaction of GPs with regard to the reform strategy. METHOD: GPs throughout Australia were approached via a popular GP magazine to express their views in a questionnaire comprising closed-end and open-ended questions enquiring about satisfaction with their current role and sources of satisfaction (and dissatisfaction) of working in general practice. Factor analysis was used to identify different sources of satisfaction (and dissatisfaction), which were intercorrelated and which together represented underlying factors. Logistic regression modelling was used to determine which sources were most strongly associated with being satisfied (or not satisfied), and to explore GP characteristics associated with satisfaction. RESULTS: A total of 2186 questionnaires were returned, representing the opinions of 14-18% of Australian GPs. Two-thirds (68%) of respondents reported being satisfied, most frequently with the variety of work and establishing relationships with patients and their families. Six satisfaction factors were identified on factor analysis, the most important characterizing social and interpersonal roles. Leading sources of dissatisfaction related to perceived interference by the government. Six dissatisfaction factors were identified on factor analysis, the most important characterizing governmental issues. However, on logistic regression other sources of dissatisfaction (reflecting disillusionment) were most strongly associated with not being satisfied. CONCLUSIONS: The main sources of satisfaction are those which typify the long-term caring role of the community GP. While the reform strategy aimed to address problems with the organization and financing of general practice, the resulting intervention is the focus of dissatisfaction. Among dissatisfied GPs these attitudes may arise primarily from a sense of disillusionment.

The relationship between childhood sexual abuse and alcohol abuse in women--a case-control study.

AIMS: The aim of this paper was to examine the association between reporting childhood sexual abuse (CSA) and alcohol abuse in a community sample of women using multivariate analysis which took into account a range of potential confounding variables (such as a family history of alcoholism) and effect modifiers (such as having an alcoholic partner). DESIGN: A two-stage retrospective case-control study was used to investigate the relationship between reporting CSA and alcohol abuse in women. PARTICIPANTS: Seven hundred and ten women randomly selected from the Australian federal electoral rolls. MEASUREMENTS: The Alcohol Use Disorders Identification Test (AUDIT) was used to measure alcohol abuse. A series of questions based on those developed by Wyatt (1985) were used to ascertain the prevalence of CSA. FINDINGS: The final model showed that the relationship between a history of CSA and alcohol abuse reflected a complex interaction between CSA and a range of other factors in a woman's background. CSA was not by itself a significant predictor of alcohol abuse (OR = 0.61; 95% CI = 0.31-1.20). However, a history of CSA became significant in combination with co-factors which included: having a mother who was perceived as cold and uncaring; having an alcoholic partner; and believing that alcohol is a sexual disinhibitor. CONCLUSION: This study indicates that CSA alone is not a causative factor in the development of alcohol abuse among women and highlights the importance of examining the family background of women with alcohol problems.

Respiratory effects associated with indoor nitrogen dioxide exposure in children.

BACKGROUND: The human health effects of exposure to indoor nitrogen dioxide (NO2) are unclear, and few studies have examined the effects of short-term peak levels of exposure. METHODS: The association between indoor exposure to NO2 and respiratory illness was examined in 388 children aged 6-11 years. The NO2 levels were monitored during winter in 41 classrooms, from four schools with unflued gas heating and four schools with electric heating. Each classroom was monitored daily with 6-hour passive diffusion badge monitors over nine alternate weeks, and with hourly monitors over two of those weeks. Children living in homes with unflued gas appliances were also monitored daily over four evenings during times of gas use. RESULTS: Exposure to NO2 at hourly peak levels of the order of > or = 80 ppb, compared with background levels of 20 ppb, was associated with a significant increase in sore throat, colds and absences from school. An increase in cough with phlegm was marginally significant. Significant dose-response relationships were demonstrated for these four measures with increasing levels of NO2 exposure. CONCLUSIONS: Short-term peak levels of exposure are important to consider in relation to adverse respiratory effects associated with NO2 exposure.

Characteristics of longer consultations in Australian general practice.

OBJECTIVE: To assess the association between general practitioner (GP) billing for "longer" consultations, patient factors linked with health care need, and other consultation characteristics. DESIGN: Retrospective analysis of data from Medicare (1984-1992), Australian Morbidity and Treatment Survey (1990-1991) and Australian Capital Territory Record Linkage Study (1988-1992). SETTING: Australian general practice, 1984 (introduction of Medicare) to 1992. MAIN OUTCOME MEASURES: Consultations billed as longer (> or = 20 or > 25 minutes) compared with standard; type of billing (bulk or private); patient health care need (defined as health and sociodemographic factors linked to worse health outcomes); consultation continuity, type of care given and number of problems managed. RESULTS: Longer billed consultations increased between 1984 and 1992, from 2.8% to 6.7% of all standard and longer consultations. Longer consultations were more likely to be bulk-billed than privately billed (odds ratio [OR], 1.74). They were more likely than standard consultations to deal with psychological diagnoses (OR, 2.06; 95% confidence interval [95% Cl], 1.83-2.32) or multiple problems (OR for four versus one diagnosis, 5.18; 95% Cl, 4.31-6.22) and to involve patients aged under 50 years, new to the practice or with new problems, but not chronic disease. In the ACT, those billed for longer consultations were more commonly tertiary educated (OR, 1.99; 95% Cl, 1.35-2.94), bulk-billed (OR, 2.75; 95% Cl, 2.51-3.10), aged 40-49 years and non-obese. CONCLUSION: Longer billed consultations were not associated with greater patient need, other than psychosocial need, but with bulk billing and patient socioeconomic advantage. However, evaluation was complicated by the effects of continuity of care and number of problems managed in the consultation.

Health effects of exposure to cyanobacteria (blue-green algae) during recreational water-related activities.

The aim of this study was to investigate effects on health of exposure to cyanobacteria as a result of recreational water activities. Participants, who were aged six years and over, were interviewed at water recreation sites in South Australia, New South Wales and Victoria on selected Sundays during January and February 1995. Telephone follow-up was conducted two and seven days later to record any subsequent diarrhoea, vomiting, flu-like symptoms, skin rashes, mouth ulcers, fevers and eye or ear irritations. On the Sundays of interview, water samples from the sites were collected for cyanobacterial cell counts and toxin analysis. There were 852 participants, of whom 75 did not have water contact on the day of interview and were considered unexposed. The 777 who had water contact were considered exposed. No significant differences in overall symptoms were found between the unexposed and exposed after two days. At seven days, there was a significant trend to increasing symptom occurrence with duration of exposure (P = 0.03). There was a significant trend to increasing symptom occurrence with increase in cell count (P = 0.04). Participants exposed to more than 5000 cells per mL for more than one hour had a significantly higher symptom occurrence rate than the unexposed. Symptoms were not correlated with the presence of hepatotoxins. These results suggest symptom occurrence was associated with duration of contact with water containing cyanobacteria, and with cyanobacterial cell density. The findings suggest that the current safety threshold for exposure of 20,000 cells per mL may be too high.

Repetitive industrial work and neck and upper limb disorders in females.

A cross-sectional study was performed in which physical examinations of the neck and upper limbs were conducted on 82 currently working female industrial workers with exposure to repetitive work tasks and on 64 currently working referent subjects without exposure to repetitive work tasks. Associations between results of symptom questions and physical examination were sought with variables related to the work environment and to the individuals. In a multivariate model, there were statistically significant associations between exposure to repetitive work and diagnoses in both the neck/shoulders (prevalence odds ratio, POR = 4.6) and elbows/hands (POR = 3.5). In addition, age (POR = 1.9, 75th vs. 25th percentiles), tendencies towards subjective muscular tension (POR = 2.3), and stress/worry (POR = 1.9) were also associated with diagnoses in the neck/shoulders; however, there was not an association between these variables and the prevalence of diagnoses in elbows/hands. Standardized evaluation of videotape recordings in 74 of the industrial workers revealed significant associations between neck flexion, and elevation and abduction of the arm and the prevalence of neck/shoulder diagnoses. In the multivariate model, neck flexion was significantly associated with diagnoses in the neck/shoulders (p = 0.005). In addition, low muscle strength, lack of emotional well-being at work, and a variety of psychosomatic symptoms were associated with diagnoses in the neck/shoulders (all p < 0.001). Lack of strength was also associated with disorders of elbows/hands (p = 0.007). This study demonstrated a substantial prevalence of neck and upper limb disorders associated with repetitive work performed with a flexed neck and elevated and abducted arms, as well as a possible potentiation of these ergonomic factors by certain personal traits in some workers.

An assessment of neck and upper extremity disorders by questionnaire and clinical examination.

To study the usefulness of a screening questionnaire for neck/upper extremity complaints, 165 women in either repetitive industrial, or mobile and varied work, were studied by the questionnaire and by a detailed clinical physical examination. A total of 94 subjects recorded complaints in the questionnaire. In 140 subjects findings were recorded at the examination. Most subjects with findings at the clinical examination of shoulders reported complaints in the questionnaire (sensitivity 80%). For the other anatomical regions, the sensitivity was rather low (42-65%). For all regions, most subjects without findings reported no complaints (specificity 77-97%). A total of 75 subjects were given clinical diagnoses according to a set of predetermined diagnostic criteria. The capacity of the questionnaire to identify diagnoses of shoulders was higher (sensitivity 92%) than for the other regions (66-79%). Of subjects who did not qualify for diagnosis, a majority (specificity 71-81%) did not report complaints in the questionnaire. We conclude that the questionnaire approach gives a fairly good picture of the neck/upper extremity status of a working female population. However, a clear view of the size of a problem is obtained only by a detailed clinical examination, particularly as regards the neck, elbows and hands, for which the questionnaire gave an underestimate.

Retention patterns of asbestos fibres in lung tissue among asbestos cement workers.

Retention patterns in lung tissue (determined by transmission electron microscopy and energy dispersive spectrometry) of chrysotile, tremolite, and crocidolite fibres were analysed in 69 dead asbestos cement workers and 96 referents. There was an accumulation of tremolite with time of employment. Among workers who died within three years of the end of exposure, the 13 with high tremolite concentrations had a significantly longer duration of exposure than seven in a low to intermediate category (medians 32 v 20 years; p = 0.018, one sided). Crocidolite showed similar patterns of accumulation. In workers who died more than three years after the end of exposure, there were no correlations between concentrations of amphibole fibres and time between the end of exposure and death. Chrysotile concentrations among workers who died shortly after the end of exposure were higher than among the referents (median difference in concentrations 13 million fibres (f)/g dry weight; p = 0.033, one sided). No quantitative differences in exposure (duration or intensity) could be shown between workers with high and low to intermediate concentrations. Interestingly, all seven workers who had had a high intensity at the end of exposure (> 2.5 f/ml), had low to intermediate chrysotile concentrations at death, whereas those with low exposure were evenly distributed (31 subjects in both concentration categories); hence, there was a dependence between last intensity of exposure and chrysotile concentration (p = 0.014). Among 14 workers with a high average intensity of exposure, both those (n = 5) with high tissue concentrations of chrysotile and those (n = 10) with high tissue concentrations of tremolite fibres had more pronounced fibrosis than those with low to intermediate concentrations (median fibrosis grades for chrysotile: 2 v 1, p = 0.021; for tremolite: 2 v 0.5, p = 0.012). Additionally, workers who died shortly after the end of exposure with high concentrations of chrysotile and crocidolite had smoked more than those with low intermediate concentrations (medians for chrysotile 35 v 15 pack-years, p = 0.030; for crocidolite 37 v 15 pack-years, p = 0.012). The present data indicate that chrysotile has a relatively rapid turnover in human lungs, whereas the amphiboles, tremolite and crocidolite, have a slower turnover. Further, chrysotile retention may be dependent on dose rate. Chrysotile and crocidolite deposition and retention may be increased by tobacco smoking; chrysotile and tremolite by fibrosis.

In vivo measurements of lead in bone in long-term exposed lead smelter workers.

In-vivo measurements of lead concentrations in calcaneus (mainly trabecular bone) and tibia (mainly cortical bone) were performed by x-ray fluorescence (XRF) in 70 active and 30 retired lead smelter workers who had long-term exposure to lead. Comparison was made with 31 active and 10 retired truck assembly workers who had no known occupational exposure to lead. After physical examination, all participants provided blood and urine samples and answered a computerized questionnaire. Since 1950, blood lead has been determined repeatedly in lead workers at the smelter, which made it possible to calculate a time-integrated blood lead index for each worker. Lead concentrations in blood, urine, calcaneus, and tibia in active and retired lead workers were significantly higher than in the corresponding control groups (p < .001). The highest bone lead concentrations were found among retired lead workers (p < .001), which was the result of considerably higher lead exposure during 1940 to 1960. Lead concentrations in calcaneus in active lead workers were significantly higher than in tibia when expressed in ug of lead per gram of bone mineral, which suggests a quicker absorption over time in this mainly trabecular bone. The estimated biological half-times were 16 y in calcaneus (95% confidence interval [95% CI] = 11-29 y) and 27 y in tibia (95% CI = 16-98 y). A strong positive correlation was found between lead concentrations in calcaneus and tibia for all lead workers (r = 0.54; p < .001). A strong positive correlation was also found between the bone lead concentrations and the cumulative blood lead index. Blood lead, at the time of study, correlated well with bone lead concentrations in retired--but not in active--workers, reflecting the importance of the endogenous (skeletal) lead exposure. The findings in this study indicate that bone lead measurements by XRF can give a good index of long-term lead exposure. Tibia measurements offer a higher precision than calcaneus measurements. The method is of particular interest in epidemiologic studies of adverse health effects caused by long-term lead exposure.

Mortality and tumour morbidity among Swedish market gardeners and orchardists.

In order to investigate possible effects of exposure to pesticides, mainly fungicides and insecticides, we studied a cohort of 2370 subjects, who, during the period 1965-1982, had been members of a horticulturists' trade association (market gardeners and orchardists). Compared to a regional reference population, total mortality (542 deaths; standardized mortality morbidity ratio, SMR = 0.8; 95% confidence limits, CLs = 0.7, 0.9) and mortality due to malignant tumours (133 deaths, SMR = 0.9; CLs = 0.7, 1.0), and cardiovascular and respiratory deaths were somewhat decreased. Suggestive excesses in mortality were seen for mental disorders and tumours of the stomach, skin and nervous system. The tumours of the nervous system were in particular excess in the young and middle-aged horticulturists (below age 60; six cases, SMR = 2.9; CLs = 1.1, 6.2). During the period 1965-1986, the total tumour morbidity was slightly decreased (255 cases; SMR = 0.9; CLs = 0.8, 1.0), as were gastrointestinal and respiratory tract tumours. The incidence of melanomas was increased (15 cases, SMR = 2.1; CLs = 1.2, 3.5), and tumours of the female genital organs, myelomas, and brain tumours (12 cases, SMR = 1.5; CLs = 0.8, 2.7) were slightly numerically elevated. Brain tumours in the young and middle-aged horticulturists (11 cases, SMR = 3.2; CLs = 1.6, 5.7), including meningiomas (four observed, SMR = 6.8; CLs = 1.9, 17.4), were increased, especially in the period 1975-1979. The mortality and tumour morbidity patterns in gardeners and orchardists, analysed separately, were similar to the patterns in all the horticulturists.(ABSTRACT TRUNCATED AT 250 WORDS)

Indoor radon-daughter concentration and gamma radiation in urban and rural homes on geologically varying ground.

The radon (Rn)-daughter level (track film, 3 months) was lower in 129 urban than in 197 rural houses (geometric means, (GM) 18 versus 40 Bq/m3; P < 0.001; range 3-416). In rural dwellings higher levels were found in those built over deposits of alum shale occurrences (P = 0.04; 12 on porous glaciofluvial cover 94 Bq/m3; 127 others 43 Bq/m3; significant interaction, P = 0.01), than in 158 others (37 Bq/m3). There was no systematic effect of the type of water supply, neither of indoor smoking. One hundred twenty three homes with a complete cellar were lower than 200 with no or part cellar (18 versus 40 Bq/m3; P < 0.001). There was only a weak association between log-transformed gamma radiation (GM 10, range 33-50 microR/h) and Rn-daughter levels (r = 0.18; 95% confidence interval 0.07-0.28). Our results show the importance for indoor Rn-daughter levels of the bedrock and cover beneath the house, and the need for Rn-daughter measurements in epidemiological studies.