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Biomedical subjects

R E Dales

Publications and source records attributed to R E Dales.

At least 37 records · Page 2Linked to original sources
PubMed1997

Indoor air quality and health: validity and determinants of reported home dampness and moulds.

BACKGROUND: Questionnaire-based surveys from several countries have consistently detected adverse health associated with home dampness and mould growth. METHODS: To test the validity of questions commonly used to indicate the presence of indoor mould, questionnaires were administered in 403 homes where dust samples were taken for viable fungi and air samples for ergosterol. RESULTS: Geometric mean concentrations of the total viable fungi were 255 (SE 116) x 10(3) CFU/g when mouldy odours were reported and 155 (SE 55) when odours were not reported (P = 0.01). Similarly, reported water damage was associated with a 50% increase (P = 0.06). Geometric mean concentrations of the predominantly indoor-source fungi, Aspergillus plus Penicillium, were twice as high when mould or mildew was reported than when not mentioned (P = 0.01). The presence of reported mould or water damage was unrelated to the presence of detectable levels of ergosterol. There was evidence for reporting bias: in the presence of low concentrations of viable fungi in dust, respondents reporting allergies were more likely to report visible mould growth (odds ratio [OR] = 1.8, 95% confidence interval [CI]: 0.9-3.5, P = 0.10. In the presence of elevated concentrations of dust fungi, respondents who smoked were less likely to report visible mould growth, (OR = 0.4, 95% CI: 0.2-0.7, P = 0.005). CONCLUSIONS: Reported mould, water damage, and mouldy odours were associated with elevated levels of indoor fungi. However, inaccuracy was high and there was evidence of a systematic reporting bias. Future research should concentrate on developing accurate objective measures of exposure to fungi, and then use this information to develop valid questionnaires. Currently, objective measures not questionnaires, are recommended to clarify the health effects of indoor fungi.

Adult↗
PubMed1997

Association between ambient carbon monoxide levels and hospitalizations for congestive heart failure in the elderly in 10 Canadian cities.

We examined the role that ambient air pollution plays in exacerbating cardiac disease by relating daily fluctuations in admissions to 134 hospitals for congestive heart failure in the elderly to daily variations in ambient concentrations of carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, and the coefficient of haze in Canada's 10 largest cities for the 11-year period 1981-1991 inclusive. We adjusted the hospitalization time series for seasonal, subseasonal, and weekly cycles and for hospital usage patterns. The logarithm of the daily high-hour ambient carbon monoxide concentration recorded on the day of admission displayed the strongest and most consistent association with hospitalization rates among the pollutants, after stratifying the time series by month of year and adjusting simultaneously for temperature, dew point, and the other ambient air pollutants. The relative risk for a change from 1 ppm to 3 ppm, the 25th and 75th percentiles of the exposure distribution, was 1.065 (95% confidence interval = 1.028-1.104). The regression coefficients of the other air pollutants were much more sensitive to simultaneous adjustment for either multiple pollutant or weather model specifications.

Aged↗
PubMed1997

The radiographic prevalence of hilar and mediastinal adenopathy in adult cystic fibrosis.

BACKGROUND: It has been stated that the hilar and mediastinal lymph nodes in adults with cystic fibrosis are invariably enlarged from chronic inflammation. However, until correlation with computed tomography and magnetic resonance imaging became possible, the visualization of this feature on plain chest radiographs received very little attention, and even the advent of these modalities, little has been written on the subject. OBJECTIVE AND METHODS: To determine the frequency of positive radiographic evidence of hilar and mediastinal adenopathy, the chest radiographs of 48 adult patients with cystic fibrosis were reviewed. RESULTS: Adenopathy was found in a total of 25 (52%) of the patients hilar in 22 (46%) and mediastinal in 21 (44%). The adenopathy was chronic and slowly progressive in all of the patients, and in no case did it resolve. The distribution of the adenopathy resembled sarcoidosis in 19 of the 25 patients and lymphoma in another patient. CONCLUSIONS: The diagnosis of adenopathy was thought to be acceptably accurate: among patients for whom CT scans were also available, CT confirmed the radiographic diagnosis of abnormality in 22 of 24 sets of hilar lymph nodes and all 14 sets of mediastinal lymph nodes. When observed on chest radiography, mediastinal adenopathy was invariably widespread throughout the mediastinum. The presence of adenopathy was correlated with more severe pulmonary involvement, as assessed by the Brasfield scoring system. However, the importance of observing adenopathy radiographically lies in allaying concerns about the development of sarcoidosis or systemic lymphatic disease in these patients and preventing unnecessary concern and investigation.

Adolescent↗
PubMed1996

Framing effects on expectations, decisions, and side effects experienced: the case of influenza immunization.

OBJECTIVE: To examine the effects of using positive or negative frames to describe influenza vaccine benefits and side effects on patients' expectations, decisions, decisional conflict, and reported side effects. METHODS: 292 previously unimmunized patients with chronic respiratory or cardiac disease were randomly assigned to receive benefit/risk information that was framed: (1) positively as the percentage who remain free of influenza and have no vaccine side effects, or (2) negatively as the percentage who acquire influenza and have vaccine side effects. Questionnaires elicited expectations, decisions, and decisional conflict. Vaccines were telephoned 3 days later for a self-report of local and systemic side effects and work absenteeism. RESULTS: Both groups had similar immunization rates and decisional conflict scores. The positive frame group had lower and more realistic expectations of vaccine side effects, fewer systemic side effects, and less work absenteeism (p < 0.05). CONCLUSION: In contrast to previous studies of health care workers, framing did not influence patients' decisions, possibly due to the patients' awareness of their higher risk of influenza complications and greater desire to follow recommendations. The common practice of using negative frames when describing probabilities of side effects may need to be reexamined, considering its deleterious influence on self-reported side effects and work absenteeism.

Aged↗
PubMed1996

Respiratory infections and the autumn increase in asthma morbidity.

Unexplained autumn increases in hospital admissions for asthma have been reported in many countries, including the United States, Canada, England and Wales. To investigate the role of infection, the association was tested between hospital admissions for asthma and respiratory infections among preschool children in Metropolitan Toronto, Canada during the period 1981 to 1989. The seasonal pattern in overall hospital utilization was assessed by admissions for nonrespiratory diseases. Time series analysis was used to remove potentially confounding temporal trends and the influence of correlated errors. A fourfold increase in asthma admissions occurred between July and October unaccompanied by similar increases in nonrespiratory admissions. Admissions began increasing during the third week of August, peaked during the third week in September, and slowly decreased during November and December. After adjusting for serial correlation, trends, climate, ambient air pollution and aeroallergens, the seasonal pattern of respiratory infection explained 14% of the variance in asthma admissions. Based on seasonal patterns, respiratory infection is the major identifiable risk factor for the large autumnal increase in asthma admissions.

Air Pollutants↗
PubMed1995

Risk factors for recurrent emergency department visits for asthma.

BACKGROUND: Patients presenting with asthma to emergency departments have lost control of their disease, have significant airways obstruction, and frequently require admission to hospital. Although even one visit is not desirable, there is a more disturbing subgroup who repeatedly visit the emergency department. METHODS: To investigate the reasons for multiple emergency visits, a questionnaire was given to 448 consecutive patients presenting to the two largest adult emergency departments in Ottawa, Canada between November 1989 and April 1991. Within this cohort, those who had made at least three visits in the past year were compared with controls (only one visit in the past year). RESULTS: Although inhaled corticosteroid use increased with multiple visits (indicating increased asthma severity), only 60% of those visiting at least three times in the past year were taking inhaled corticosteroids. Chronic undermedication relative to disease severity was apparent among the cases. The number of visits was associated with nocturnal asthma on a regular basis, work and school absenteeism, frequent visits to their regular physician, and frequent admissions to hospital. Visits were not related to psychological health, environmental allergens/irritants, or lack of perceived asthma severity. CONCLUSIONS: The recommendations of current asthma guidelines are not reaching these patients. The issue of translating guidelines from paper to practice must be addressed before highly effective medications can have an important impact on the frequency of emergency department visits.

Adrenal Cortex Hormones↗
PubMed1994

Cystic fibrosis carrier screening in a high-risk population. Participation based on a traditional recruitment process.

OBJECTIVE: Recent advances in molecular genetic (DNA) technology have permitted identification of previously undetectable cystic fibrosis (CF) carriers. Although research has been initiated in the general population, to our knowledge no published studies have looked at the utilization of DNA-based carrier screening in the high-risk CF population (family history of CF). DESIGN: Cross-sectional, diagnostic open trial. SETTING: Carrier testing was offered to a high-risk CF population via adult patients with CF or parents of pediatric patients with CF attending two regional CF clinics over a 3-year period. PARTICIPANTS: Consecutive sample of virtually all patients with CF (n = 118) from a population of 1 million. MAIN RESULTS: Despite free services, written follow-up, and counseling for 99% of patients attending the CF clinic, there was less than 10% participation from high-risk family members (168 blood relatives and 26 spouses of identified carriers or patients with CF; 38 and 156 persons from the adult and pediatric clinic families, respectively). Nevertheless, we identified 91 CF carriers among the 168 high-risk relatives. This is comparable to the number of carriers detected in general population carrier screening that has tested substantially more individuals (> 3000 per study). CONCLUSIONS: Our results suggest that research concerning CF carrier screening not only focus on data about fundamental program resources and numbers of carriers detected but also investigate how information about the availability of carrier screening is disseminated, the motivation behind testing, and the perceived relevance of test results by those tested in the high-risk population. These issues are increasingly relevant as screening becomes feasible using DNA testing for far more prevalent disorders (such as breast cancer and diabetes).

Adolescent↗
PubMed1994

Effects of low ambient levels of ozone and sulfates on the frequency of respiratory admissions to Ontario hospitals.

To investigate the acute respiratory health effects of ambient air pollution, the number of emergency of urgent daily respiratory admissions to 168 acute care hospitals in Ontario were related to estimates of exposure to ozone and sulfates in the vicinity of each hospital. Ozone levels were obtained from 22 monitoring stations maintained by the Ontario Ministry of the Environment for the period January 1, 1983 to December 31, 1988. Daily levels of sulfates were recorded at nine monitoring stations representing three different networks operated by the Ontario Ministry of the Environment and Environment Canada. Positive and statistically significant associations were found between hospital admissions and both ozone and sulfates recorded on the day of admission and up to 3 days prior to the date of admission. Five percent of daily respiratory admissions in the months of May to August were associated with ozone, with sulfates accounting for an additional 1% of these admissions. Ozone was a stronger predictor of admissions than sulfates. Positive and statistically significant (P < 0.05) associations were observed between the ozone-sulfate pollution mix and admissions for asthma, chronic obstructive pulmonary disease, and infections. Positive associations were also found in all age groups, with the largest impact on infants (15% of admissions associated with the ozone-sulfate pollution mix) and the least effects on the elderly (4%). Temperature had no effect on the air pollution-admission relationship. Ozone (lagged 1 day) and sulfates (lagged 1 day) displayed a positive association with respiratory admissions for 91 and 100% of the 168 acute care hospitals, respectively. Air pollution was not related to a class of nonrespiratory admissions, which served as a negative control, nor was it related to admissions in the winter months of December to March, when ozone and sulfate levels are low and when people spend a considerable amount of time indoors.

Adolescent↗
PubMed1994

Quality-of-life following thoracotomy for lung cancer.

Contrary to the issues of perioperative morbidity and survival following surgery for lung cancer, little attention has been given to quality-of-life. To address this, quality-of-life was assessed preoperatively and 1, 3, 6 and 9 months postoperatively in a cohort of 117 consecutive subjects who underwent thoracotomy with a certain or presumptive diagnosis of lung cancer. Those with cancer (n = 91) confirmed at thoracotomy were contrasted to those without (n = 26). Moderate to severe dyspnea, reported in 14% preoperatively, increased to 34% at 1 and 3 months (p < 0.005) but returned to approximately 10% at 6 and 9 months. Similarly, activities of daily living were impaired in 11% preoperatively; this disability increased to 21% at 1 month (p < 0.005), and returned to baseline at 6 and 9 months. Those with cancer compared to those without a postoperative diagnosis of cancer had similar quality-of-life preoperatively but deteriorated more in the postoperative period. This study demonstrates that important deterioration in quality-of-life occurs during the first 3 months postoperatively in those with a final diagnosis of cancer but improvement back to baseline can be expected thereafter.

Activities of Daily Living↗
PubMed1994

Prevalence of childhood asthma across Canada.

BACKGROUND: A large cross-sectional study provided an opportunity to estimate the prevalence of childhood asthma in several regions across Canada. METHODS: In 1988, approximately 18,000 questionnaires were distributed to the families of 5-8 year old children in 30 communities from the following six regions across Canada: the interior of British Columbia, southeastern Saskatchewan, southwestern Ontario, the central region of Ontario, southern Quebec, and the Maritimes (Nova Scotia and Prince Edward Island). These communities were free of point-source air pollutants and selected to represent a range of ambient sulphate concentrations. In all 14,948 questionnaires were returned representing an 83% response rate. RESULTS: Currently present, physician-diagnosed asthma was reported for 4.7% of children by their parents. Persistent wheezing was reported for 13% and persistent cough for 5.9%. Asthma was most common in the two Maritime provinces (7.4%), and least common in British Columbia (3.3%) and Quebec (3.4%). Similar regional differences were seen for persistent cough, persistent wheeze, and also hospital separation rates for asthma which were approximately 800 per 100,000 for the Maritimes and 396 per 100,000 for British Columbia. Differences persisted despite adjustments for several host and environmental (indoor and outdoor) characteristics. CONCLUSIONS: The east coast of Canada may be an endemic area of asthma in Canada. If confirmed by objective measures of asthma, a detailed aetiologic investigation could enhance understanding of this phenomenon and the major environmental determinants of asthma morbidity in general.

Age Factors↗
PubMed1993

Preoperative prediction of pulmonary complications following thoracic surgery.

The ability of preoperative quality-of-life and physiologic variables to predict postoperative complications was tested in 117 consecutive patients undergoing thoracotomy for possible or definite lung cancer. Preoperatively, quality of life was globally assessed by the QLI and Sickness Impact Profile. Dyspnea was assessed by the Clinical Dyspnea Index and a modified Pneumoconiosis Research Unit question. Spirometry and maximal exercise testing were carried out in 115 and 46 subjects, respectively. Thirty-seven percent experienced at least one respiratory complication (eg, pneumonia, atelectasis prompting bronchoscopy, pulmonary embolism). Twofold or greater increases in respiratory complications were associated with current smoking (p < 0.05), cancer as the final pathologic condition (p < 0.10), at least moderate dyspnea (p < 0.10), FEV 1 < 60 percent of predicted (p < 0.05), ventilatory reserve < 25 L (p < 0.05), and VO2max < 1.25 L (p < 0.05). Twofold increases in the incidence of any complication (respiratory, cardiac, etc) were associated with age > or = 75 years (p < 0.05) and cancer as the final pathologic condition (p < 0.05). We conclude that simple historic information (age, smoking status, cancer status, dyspnea) indicates the risk of postoperative morbidity. General quality-of-life measures were not good predictors of morbidity. Our findings corroborate the few studies supporting the value of VO2max and suggest that the usefulness of the ventilatory reserve deserves further attention.

Activities of Daily Living↗
PubMed1992

Does forced air heating exacerbate asthma?

Asthma morbidity increases in the Canadian autumn coincident with the beginning of home heating. To test the hypothesis that forced air heating exacerbates asthma, 51 subjects were randomly assigned to one of two groups: the intervention (off1-on2) group was instructed to keep their home forced air heating off from September 9 to 17 and then to set the thermostat to 22 degrees C from 8 PM to 8 AM between September 18 and 25. The concurrent control (off1-off2) group was instructed to keep their forced air heating off during the entire study period. Forty-eight of the 51 subjects randomized recorded morning peak flows, asthma symptoms, and bronchodilator use during the study period. For the intervention group, results before compared with during home heating, respectively, were as follows: mean nocturnal awakenings 0.36 versus 0.36; any breathing difficulties an awakening 82% versus 73%; mean morning peak flows 406 lpm versus 409 lpm, a difference of 3.3% +/- 6.7% (SEM), p = 0.6. There was a 95% probability that the true change in peak flows with forced air was less than 2%. For the control group, the comparable results were as follows: mean nocturnal awakening 0.40 versus 0.47; breathing difficulties on awakening 40% versus 47%; mean morning peak flows 400 lpm versus 399 lpm (p = 0.9). The commencement of forced air heating did not exacerbate asthma in this clinical population and is therefore unlikely to be an important problem for most people suffering from asthma.

Adolescent↗
PubMed1992

Asthma management preceding an emergency department visit.

BACKGROUND: The burden of illness from asthma in North America has not decreased despite advancements in understanding disease pathogenesis and improved pharmacotherapeutics. This study examined the adequacy of preventive measures applied to asthma. METHODS: Using a standardized self-administered questionnaire, 111 consecutive patients presenting to the emergency department because of asthma were surveyed about their "usual" level of disability from asthma, usual medications, self-management plans to deal with an asthma attack, and environmental control measures. RESULTS: Twenty-five percent of subjects suffered sleep disturbance more than 15 days per month, had work/school attendance affected more than 14 days per year, and previously visited an emergency department twice in the past year. Thirty-seven percent had no effective plans to deal with an attack and another 32% had plans that were never discussed with a physician. Although 78% reported that cigarette smoke aggravated their asthma, one third of these were exposed at home. CONCLUSIONS: For a significant proportion of adults requiring emergency health services for asthma, preexisting management was poor by current standards. We recommend that patients be screened by emergency physicians and those with identifiable inadequacies in usual care be referred to physicians with expertise in asthma management.

Adult↗
PubMed1992

Chronic cough responsive to ibuprofen.

A 57-year-old woman believed that ibuprofen, prescribed for back pain, improved her idiopathic chronic cough that had been resistant to inhaled and oral corticosteroids. To confirm this observation, we performed an n-of-1 clinical trial with four treatment periods, each separated by a 4-day washout. Ibuprofen 1800 mg/day for 6 days or placebo was randomly allocated in a double-blind fashion with a block size of 4. The number of coughs during the first 30 minutes after awakening were counted daily throughout the study using a tape recorder. Sixty-two coughs/hour occurred while taking ibuprofen, compared with 164 with placebo. We conclude that ibuprofen may be effective in idiopathic chronic cough, and suggest that prostaglandins may be pathogenic factors in some patients.

Chronic Disease↗
PubMed1991

Respiratory health effects of home dampness and molds among Canadian children.

In 1988, the authors conducted a questionnaire-based study on the health effects of the indoor environment in 30 Canadian communities. This paper focuses on the association between the respiratory health of young children and home dampness and molds. A total of 17,962 parents or guardians of schoolchildren received a questionnaire, and 14,948 (83.2%) questionnaires were returned. Children living in mobile homes, tents, and boats were excluded as were those with cystic fibrosis, leaving 13,495 children included in the study group. The housing stock was distributed as follows: 81% were one-family detached homes, 6% were one-family attached homes, and 13% were buildings for two or more families. Molds were reported in 32.4%, flooding in 24.1%, and moisture in 14.1% of the homes. Prevalences of all respiratory symptoms were consistently higher in homes with reported molds or dampness; i.e., adjusted odds ratios ranged from 1.32 (95% confidence interval 1.06-1.39) for bronchitis to 1.89 (95% confidence interval 1.58-2.26) for cough. The prevalence of home dampness or molds, 37.8%, indicates that it is an important public health issue. Further studies are required to elucidate the pathogenesis.

Canada↗
PubMed1991

Adverse health effects among adults exposed to home dampness and molds.

To investigate the association between home dampness and mold and health, questionnaires were administered through the primary school system to parents of school-aged children in six regions of Canada. The present report focuses on the symptoms of the 14,799 adults at least 21 yr of age. The overall response rate was 83%, and missing values for individual variables ranged from 3 to 8%. The presence of home dampness and/or molds (that is, damp spots, visible mold or mildew, water damage, and flooding) was reported by 38% of respondents. The prevalence of lower respiratory symptoms (any cough, phlegm, wheeze, or wheeze with dyspnea) was increased among those reporting dampness or mold compared with those not reporting dampness or mold as follows: 38 versus 27% among current smokers, 21 versus 14% among exsmokers, and 19 versus 11% among nonsmokers (all p values less than 0.001). This association persisted after adjusting for several sociodemographic variables (including age, sex, and region) and several other exposure variables (including active and passive cigarette smoke, natural gas heating, and wood stoves). The odds ratio between symptoms and dampness was 1.62 (95% confidence interval, 1.48 to 1.78) in the final model chosen. This association persisted despite stratification by the presence of allergies or asthma. Exposure to home dampness and mold may be a risk factor for respiratory disease in the Canadian population.

Adult↗