Biomedical subjects

P Corey

Publications and source records attributed to P Corey.

At least 19 recordsLinked to original sources

PubMed2001

Psychological features of subjects with idiopathic environmental intolerance.

OBJECTIVES: Idiopathic environmental intolerance (IEI) is associated with unexplained symptoms attributed to non-noxious levels of environmental substances. Clinically, some of the symptoms of IEI overlap with those of panic disorder (PD). We have recently reported a link between IEI and panic responses to a single inhalation of 35% carbon dioxide (CO(2)), a reliable panic induction challenge. This study assessed depression, stress, anxiety, and agoraphobic symptoms among IEI subjects from our previous study versus healthy controls. METHODS: Thirty-six IEI and 37 control subjects with no preexisting psychiatric history were compared on self-report psychological questionnaires. RESULTS: IEI subjects scored significantly higher than controls on the Agoraphobic Cognitions Questionnaire (ACQ), Depression Anxiety Stress Scales (DASS), and Mobility Inventory for Agoraphobia (MI) (Student's t, P<.05). CONCLUSIONS: IEI subjects represent a group with morbidity significantly higher than a control population but less than what would be expected for a clinical psychiatric population.

Adult↗

PubMed2001

Effect of a very-high-fiber vegetable, fruit, and nut diet on serum lipids and colonic function.

We tested the effects of feeding a diet very high in fiber from fruit and vegetables. The levels fed were those, which had originally inspired the dietary fiber hypothesis related to colon cancer and heart disease prevention and also may have been eaten early in human evolution. Ten healthy volunteers each took 3 metabolic diets of 2 weeks duration. The diets were: high-vegetable, fruit, and nut (very-high-fiber, 55 g/1,000 kcal); starch-based containing cereals and legumes (early agricultural diet); or low-fat (contemporary therapeutic diet). All diets were intended to be weight-maintaining (mean intake, 2,577 kcal/d). Compared with the starch-based and low-fat diets, the high-fiber vegetable diet resulted in the largest reduction in low-density lipoprotein (LDL) cholesterol (33% +/- 4%, P <.001) and the greatest fecal bile acid output (1.13 +/- 0.30 g/d, P =.002), fecal bulk (906 +/- 130 g/d, P <.001), and fecal short-chain fatty acid outputs (78 +/- 13 mmol/d, P <.001). Nevertheless, due to the increase in fecal bulk, the actual concentrations of fecal bile acids were lowest on the vegetable diet (1.2 mg/g wet weight, P =.002). Maximum lipid reductions occurred within 1 week. Urinary mevalonic acid excretion increased (P =.036) on the high-vegetable diet reflecting large fecal steroid losses. We conclude that very high-vegetable fiber intakes reduce risk factors for cardiovascular disease and possibly colon cancer. Vegetable and fruit fibers therefore warrant further detailed investigation.

Adult↗

PubMed2001

The role of symptomatic colds in asthma exacerbations: Influence of outdoor allergens and air pollutants.

BACKGROUND: Both air pollutants and respiratory viral infections have been recognized to be important triggers of asthma exacerbations, but the possible interaction of these has not been assessed in an epidemiologic study. OBJECTIVE: In this study, we aimed to assess the possible associations of symptomatic colds with outdoor allergens and air pollutants in exacerbating asthma. METHODS: A total of 57 adults and children with asthma participated in a 1-year study in Vancouver, British Columbia. Diary cards recording symptoms of asthma and colds, medication usage, and peak expiratory flow rates were completed twice daily. Outdoor air pollutant levels and levels of pollen and fungal spores were measured. Levels were examined for associations with exacerbations of asthma with symptoms of a cold, as compared with asthma exacerbations with no cold symptoms and colds in the absence of asthma exacerbations. RESULTS: Of 130 asthma exacerbations, 47% were associated with cold symptoms (accounting for 44% of episodes of colds). Asthma exacerbations with colds were associated with higher levels of sulfur dioxide, and nitric oxide during March to November in comparison with asthma exacerbations without cold symptoms (P <.018). Cold-symptom days overall were more common in winter and were significantly associated with lower temperatures, lower ozone levels, and higher sulfur dioxide, nitrogen dioxide, nitrogen oxide (NO and NO(x)), and carbon monoxide levels. CONCLUSIONS: Asthma exacerbations are commonly associated with cold symptoms. These episodes are associated with higher levels of sulfur dioxide and nitrogen oxides from March to November in comparison with asthma exacerbations without cold symptoms.

Adolescent↗

PubMed2000

Expanding the epidemiologic profile: risk factors for active tuberculosis in people immigrating to Ontario.

BACKGROUND: Many people immigrating to Canada come from countries with a high burden of tuberculosis. The aim of this study was to develop a detailed epidemiologic profile of foreign-born people with tuberculosis living in Ontario. METHODS: In this population-based case-control study, cases of tuberculosis diagnosed in 1994-1995 were identified from the database of the Ontario Reportable Disease Information Service and were considered eligible for analysis if a record of landing (receipt of permission to establish residence in Canada) from the period 1986-1995 was found in the Citizenship and Immigration Canada (CIC) database, if the person was at least 11 years of age at the time their visa was issued, and if the person had not been diagnosed with tuberculosis before becoming legally landed in Canada. Control subjects, who met the same criteria as the case subjects but who did not have tuberculosis in 1994-1995, were identified from a CIC database for landed immigrants. RESULTS: A total of 1341 cases of tuberculosis in foreign-born people were reported in Ontario in 1994-1995. A record of landing was found in CIC databases for 1099 of these people, 224 of whom were not legally landed at the time of diagnosis. In total, 602 cases met the inclusion criteria. The 2 strongest determinants of risk among those who had become landed within the preceding 10 years were referral for medical surveillance by immigration officials (odds ratio [OR] 3.8, 95% confidence interval [CI] 2.6-6.0) and world region of origin (Somalia [OR 67.7, 95% CI 31.3-154.9], Vietnam [OR 25.0, 95% CI 12.5-50.0], the Philippines [OR 11.9, 95% CI 6.0-23.3], other sub-Saharan African countries [OR 11.6, 95% CI 5.7-23.2], India [OR 9.7, 95% CI 4.9-18.9], China [OR 6.1, 95% CI 3.1-12.1], other Asian countries [OR 4.7, 95% CI 2.4-9.1], the Middle East [OR 4.1, 95% CI 2.0-8.3], Latin America [OR 1.9, 95% CI 0.9-3.8), and the former socialist countries of Europe [OR 1.8, 95% CI 0.8-3.8]; the reference category was countries with established market economies). Low socioeconomic status was an independent risk factor. INTERPRETATION: The risk of tuberculosis in groups of people migrating to Ontario is highly variable and is influenced by several factors. Successful population-based tuberculosis prevention strategies will need to accommodate this variability.

Adolescent↗

PubMed2000

Hospitalization for community-acquired, rotavirus-associated diarrhea: a prospective, longitudinal, population-based study during the seasonal outbreak. The Greater Toronto Area/Peel Region PRESI Study Group. Pediatric Rotavirus Epidemiology Study for Immunization.

OBJECTIVES: To determine the age-specific hospitalization rate for rotavirus-associated diarrhea in Canadian children during the seasonal outbreak, and to characterize children and their households, for assessment of the need for a rotavirus vaccine. DESIGN: Prospective multisite cohort study. SETTINGS AND PARTICIPANTS: Children with an admission diagnosis of diarrhea admitted to 18 hospitals serving 132 study census tracts of a major urban region, from November 1, 1997, through June 30, 1998. Prospective centralized testing of stools was performed; research nurses administered a follow-up questionnaire to parents. MAIN OUTCOME MEASURE: Age-specific diarrhea and rotavirus-associated hospitalization rates. RESULTS: Of 224160 children younger than 5 years, the diarrhea hospitalization rate was 4.8 in 1000 (n = 1086) during the seasonal epidemic. Based on testing of 65% of the hospitalized children, the rotavirus-associated diarrhea hospitalization rate was 1.3 in 1000; the cumulative incidence to 5 years of age was 1 in 160. Rotavirus-associated diarrhea was reported in 37% of the 1001 hospitalized children undergoing testing inside and outside of the census tracts; in children aged 6 to 35 months, this rose to more than 70% during April and May. Ages of children with rotavirus-associated diarrhea were 0 to 2 months (2%), 3 to 5 months (5%), 6 to 23 months (60%), 24 to 35 months (15%), and 36 months or older (19%). Of children aged 0 to 5 and 6 to 11 months, 4 (19%) of 21 and 6 (10%) of 59, respectively, had been born prematurely; 20 (24%) of 83 younger than 1 year were breastfed at the time of illness. Of children younger than 36 months, 77% were cared for in their homes; 13%, in family day care homes; and 8%, in child care centers. The mean (+/- SD) duration of rotavirus hospitalization based on hospital records and parental questioning was 2.4 +/- 1.7 and 3.1 +/- 1.6 days, respectively; it was significantly longer (P < or = .001) in children with an underlying medical condition. One child required intensive care unit hospitalization. Diarrhea occurred concurrently in 74% of household contacts younger than 3 years; 38%, aged 3 to 18 years; and 29%, older than 18 years. Seventy-six percent of parents were married. Household incomes in Canadian dollars in the 81% reporting were less than $20000 in 20%, $20000 to $60000 in 44%, and greater than $60000 in 36%. Ethnicity was reported as 53% white, 15% black, 10% Asian, 12% East Indian, and 11% other. CONCLUSIONS: Based on testing of 65% of children with diarrhea, rotavirus resulted in hospitalization in a minimum of 1 in 160 children by 5 years of age during the seasonal outbreak. Had 100% of young children with diarrhea undergone testing, the extrapolated cumulative incidence of rotavirus-associated diarrhea by 5 years of age may have been 1 in 106.

Acute Disease↗

PubMed2000

Rotavirus-associated diarrhea in outpatient settings and child care centers. The Greater Toronto Area/Peel Region PRESI Study Group. Pediatric Rotavirus Epidemiology Study for Immunization.

OBJECTIVES: To determine the prevalence of rotavirus infection in outpatient and child care center (CCC) settings during the seasonal rotavirus outbreak and to describe associated health care utilization. DESIGN: Prospective, multisite cohort study in various ambulatory settings. SETTINGS AND PARTICIPANTS: Participants were children with diarrhea (1) presenting to hospital emergency departments (EDs) and receiving intravenous (IV; n = 8) or oral (n = 1) hydration, (2) seen in pediatric practices (n=4), or (3) attending CCCs (n = 19) between November 1, 1997, and June 30, 1998. Prospective centralized testing of stool samples for rotavirus was performed using enzyme-linked immunosorbent assay and electron microscopy. Study nurses administered follow-up parent questionnaires for rotavirus-positive children. MAIN OUTCOME MEASURE: Prevalence of rotavirus-associated diarrhea. RESULTS: During the 8-month study, rotavirus was identified in 92 children with diarrhea: ED-IV, 20 (44%) of 45; ED-oral, 9 (47%) of 19; pediatric practices, 30 (20%) of 147; and CCCs, 33 (18%) of 186. Of 226 children with diarrhea in pediatric practices, all 5 who progressed to ED-IV hydration or hospitalization were tested, and 3 (60%) were rotavirus positive. Of 211 children in CCCs with diarrhea, 84% who required no health care visits were tested, and of these 10% were positive; of 56 who went on to require a health care visit and 8 who required ED-IV hydration or hospitalization, all were tested, and 27% and 75%, respectively, were rotavirus positive. Among 16 children with rotavirus followed up with ED-IV hydration, 4 (25%) returned and were hospitalized. Maximal health care intervention among 29 children with rotavirus enrolled in pediatric practices included 22 (76%) seeing the pediatrician only, 5 (17%) seeking further care in the ED, 1 (3%) receiving further ED-IV hydration, and 1 (3%) being hospitalized briefly. Maximal health care intervention for 33 children with rotavirus enrolled in CCCs included 13 (39%) who did not visit a physician, 11 (33%) who did, 3 (9%) who sought care in the ED, 1 (3%) who received ED-IV hydration, and 5 (15%) who were hospitalized. In CCCs, rates of diarrhea per 100 child-months of observation were as follows: ages 0 to 23 months, 6.6 episodes; ages 24 to 35 months, 1.9 episodes; and 3 years and older, 0.07 episodes; rates of rotavirus-associated diarrhea were as follows: ages 0 to 23 months, 1.1 episodes (28 of 2547); ages 24 to 35 months, 0.23 episodes (5 of 2185); and 3 years and older, 0 episodes (0 of 4124). CONCLUSION: Across a variety of outpatient and CCC settings, rotavirus is an important cause of diarrhea and a major cause of health care utilization.

Child↗

PubMed2000

Carbon dioxide inhalation challenges in idiopathic environmental intolerance.

BACKGROUND: Idiopathic environmental intolerance (IEI) is associated with unexplained physical symptoms, which overlap considerably with those of panic disorder (PD). OBJECTIVE: This study tested the hypothesis that patients with symptoms to suggest IEI exhibit features of PD in response to nonnoxious environmental stimuli. METHODS: A single-blind, case-control 35% carbon dioxide inhalation challenge was conducted at a university-based occupational health unit with the use of standardized psychologic questionnaires involving 36 patients with IEI and 37 healthy control subjects. The main outcome measures included panic attack symptoms and scores on the Anxiety Sensitivity Index, a measure of panic-related anxiety. RESULTS: Patients with IEI scored significantly higher on the Anxiety Sensitivity Index than control subjects did (P <.05). Significantly more patients with IEI (71%) than control subjects (26%) fulfilled panic attack criteria after carbon dioxide (P <.001). Physiologic responses to the challenge were not significantly different between groups. CONCLUSIONS: Results suggest that, similar to patients with PD, patients with IEI display high anxiety sensitivity and in response to carbon dioxide inhalation tend to experience heightened anxiety and panic attacks.

Administration, Inhalation↗

PubMed2000

Cyclooxygenase metabolites play a different role in ozone-induced pulmonary function decline in asthmatics compared to normals.

Indomethacin has been used to demonstrate that cyclooxygenase (COX) metabolites of arachidonic acid play a mechanistic role in ozone-induced spirometric decline in normals (Nm). Since the weight of evidence suggests that asthmatics (Asth) do not differ substantially from Nm subjects in the magnitude of their spirometric response to ozone, we sought to determine whether COX metabolites play a similar role in the asthmatic response to ozone. Thirteen (n = 13) Asth and nine (n = 9) Nm volunteers were pretreated with indomethacin or placebo (3 days, 75 mg/day), then exposed for 2 h to 400 ppb ozone or clean air while performing mild intermittent exercise (Vi(min) = 30 L/min.). Baseline changes in spirometry (FVC, FEV(1), FEF(25), FEF(50), FEF(60p), FEF(75)) and soluble markers of COX metabolism (prostaglandin [PG] F2-alpha) were measured from induced sputum samples. Results showed similar reductions in FVC (Asth = 12%, Nm = 10%) and FEV(1) (Asth = 13%, Nm = 11%) in Asth and Nm following ozone. Variables representing small-airways function demonstrated the greatest ozone-induced decline in Asth (FEF(75) = 25%). Indomethacin pretreatment significantly attenuated ozone-induced decreases in FVC and FEV(1) in Nm, but not in Asth. Marked attenuation of ozone-induced decrements in FEF(75) and FEF(60p) was observed in Asth but not in Nm. PGF2-alpha levels were similar in both groups prior to ozone exposure with indomethacin (Asth = 65 pg/ml, Nm = 59 pg/ml), but postexposure levels in Asth were significantly elevated (118 pg/ml) compared to Nm (54 pg/ml). We conclude that COX metabolites, such as PGF2-alpha, play an important but different role in asthmatics than normals with respect to ozone-induced pulmonary function decline. Specifically, COX metabolites contribute to restrictive-type changes in normals and obstructive-type changes in small airways in asthmatics.

Adolescent↗

PubMed2000

Etiology of community-acquired pediatric viral diarrhea: a prospective longitudinal study in hospitals, emergency departments, pediatric practices and child care centers during the winter rotavirus outbreak, 1997 to 1998. The Pediatric Rotavirus Epidemiology Study for Immunization Study Group.

OBJECTIVE: To determine the viral etiology of community-acquired diarrhea in children admitted to hospitals and presenting in emergency departments, pediatric practices and child care centers from November 1, 1997, to June 30, 1998. STUDY DESIGN: Children with diarrhea were identified in a prospective multisite cohort study and analyzed according to age, gender and duration of hospitalization. Stools were tested for rotavirus by enzyme immunoassay and for all other enteric viruses by electron microscopy. RESULTS: Of the 2524 children identified with diarrhea, stools of 1386 (55%) were tested by enzyme immunoassay for rotavirus, and of these 1365 (54%) were screened by electron microscopy for all identifiable enteric viruses. Rotavirus was found in 32% (n = 437), adenovirus in 4% (n = 55), torovirus in 3% (n = 44), Norwalk-like viruses in 2% (n = 25) and astrovirus (n = 14) and calicivirus (n = 7) in fewer than 1% of the specimens tested. The proportion of rotavirus was significantly higher in children 12 to 23 months of age (43% of tested stools, n = 159) and 24 to 35 months of age (38% of tested stools, n = 64) (P < 0.001) than in any other age group. Toroviruses were found to approximately the same extent in children > or =36 months of age (6% of tested stools, n = 19) as those <36 months of age. Rotavirus (36% of tested stools, n = 375, P < 0.0005) and torovirus (4% of tested stools, n = 43, P < 0.004) were most often found in hospitalized patients. In contrast Norwalk-like viruses (P < 0.001) and astroviruses (P < 0.01) were more commonly detected in specimens from patients who presented to physicians' offices and who were symptomatic for gastroenteritis in child care centers. CONCLUSION: This study demonstrates that although all known gastroenteritis viruses were diagnosed in symptomatic children, rotavirus was the etiologic agent in most cases of diarrhea managed in the community and in the hospital.

Child Day Care Centers↗

PubMed2000

Health-adjusted life expectancy at the local level in ontario.

Health expectancy measures are becoming a common method of combining information on mortality and health-related quality of life into one summary population health measure. However, health expectancy measures are infrequently measured at the local level, despite a shift toward health service planning to that level. Using a modified Sullivan method, we calculated health-adjusted life expectancy (HALE) for the 42 public health units in Ontario using life tables that were derived from mortality and population data for 1988-1992 and the Health Utilities Index from the 1990 Ontario Health Survey. There were large variations among health units in HALE at age 15 for both men (range: 51.3-58.2 years) and women (range: 56.6-62.9 years). Generally, rural and northern areas had the lowest HALE. Local differences in male HALE were greater than for life expectancy (7.1 versus 6.0 years). Despite a relatively large health survey (45,583 respondents, range: 729-1,746 per health unit), few HALE differences deviated significantly from the Ontario mean, raising concerns about the feasibility of estimating local health expectancy measures with adequate precision. Nevertheless, the wider local differences and different geographic distribution of local HALE compared with mortality measures, along with the additional benefit of being able to model the complex interaction of mortality and morbidity, suggest that HALE may be a useful population health measure.

Adolescent↗

PubMed1999

Clinical utility of quantitative cytomegalovirus viral load determination for predicting cytomegalovirus disease in liver transplant recipients.

BACKGROUND: The early detection of cytomegalovirus (CMV) after liver transplantation may form the basis of a preemptive strategy for prevention of active CMV disease. METHODS: We prospectively analyzed the clinical use of weekly quantitative polymerase chain reaction-(PCR) based plasma viral load determinations and the antigenemia assay for predicting the development of active CMV disease in 97 consecutive liver transplant recipients. RESULTS: CMV disease occurred in 21/97 patients. Using a positive cut-off of >400 copies/ml plasma, PCR had a sensitivity of 100%, specificity 47.4%, positive predictive value 34.4% and negative predictive value 100% for prediction of CMV disease. Respective values for a positive antigenemia (>0 positive cells/slide) were 95.2, 55.3, 37.0, and 97.7%. Different cut-off points for a positive test were analyzed using receiver-operating characteristic (ROC) curves. The optimal cut-off for viral load was in the range of 2000-5000 copies/ml (sensitivity 85.7%, specificity 86.8%, PPV 64.3%, NPV 95.7% for >5000 copies/ml). The optimal cut-off for antigenemia was in the range of four to six positive cells/slide. Mean peak viral load in symptomatic patients was 73,715 copies per/ml versus 3615 copies/ml in patients with asymptomatic CMV reactivation (P<0.001). In a multivariate logistic regression analysis of risk factors for CMV disease (CMV serostatus, acute rejection, and induction immunosuppression), peak viral load and peak antigenemia emerged as the only significant independent predictors of CMV disease (for PCR, odds ratio=1.40/1000 copy/ml increase in viral load, P=0.0001; for antigenemia odds ratio=1.17/1 positive cell/slide). CONCLUSIONS: Plasma viral load by quantitative PCR is useful for predicting CMV disease and could be used in a preemptive strategy.

Adolescent↗

PubMed1999

Convergent discriminitive, and predictive validity of the Prostate Cancer Specific Quality of Life Instrument (PROSQOLI) assessment and comparison with analogous scales from the EORTC QLQ-C30 and a trial-specific module. European Organisation for Research and Treatment of Cancer. Core Quality of Life Questionnaire.

The Prostate Cancer Specific Quality of Life Instrument (PROSQOLI) is a measure of health-related quality of life (HRQL) that was designed to be an outcome measure for clinical trials in advanced hormone-resistant prostate cancer. The cross-sectional validity of the PROSQOLI was assessed using baseline data from a randomized trial in which HRQL was also assessed with the European Organisation for Research and Treatment of Cancer (EORTC) Core Quality of Life Questionnaire (QLQ-C30) and a trial-specific quality of life module (QLM-P14). Convergent validity was assessed with the multitrait-multimethod matrix approach; discriminative validity was assessed according to conventional clinical criteria; and predictive validity was assessed by the ability to predict survival duration. These assessments provided strong support for the validity of all PROSQOLI scales except those for family/marriage relationships and passing urine; modifications of these two scales are under evaluation. The strength, consistency, and independence of the prognostic information provided by the HRQL scales were striking. Differences between the instruments were generally subtle. These data support validity of the PROSQOLI and the analogous scales from the QLQ-C30 and QLM-P14 in symptomatic men with advanced hormone resistant prostate cancer. The PROSQOLI is a short, simple, and valid measure of HRQL in this setting.

Analysis of Variance↗

PubMed1998

Responsiveness to change in health-related quality of life in a randomized clinical trial: a comparison of the Prostate Cancer Specific Quality of Life Instrument (PROSQOLI) with analogous scales from the EORTC QLQ-C30 and a trial specific module. European Organization for Research and Treatment of Cancer.

INTRODUCTION: The Prostate Cancer Specific Quality of Life Instrument (PROSQOLI) was developed to be a pragmatic outcome measure for clinical trials in symptomatic men with advanced hormone-resistant prostate cancer. DESIGN AND SETTING: A comparative assessment of responsiveness was made with longitudinal data from a positive multicenter randomized trial of palliative chemotherapy in 161 symptomatic men with advanced hormone-resistant prostate cancer. INSTRUMENTS: The PROSQOLI, the European Organisation for Research and Treatment of Cancer (EORTC) core quality of life questionnaire (QLQ-C30), and a specific quality of life module for advanced prostate cancer [QLM-P14] were administered every 3 weeks while patients received their allocated treatment. FINDINGS: Sixteen of the 19 health-related quality of life (HRQL) scales demonstrated improvements in palliative responders. All three pain scales detected a beneficial effect of palliative chemotherapy. The relative efficiency statistics favored the PROSQOLI for physical symptoms and physical function but the QLQ-C30 for emotional function, social function, and global perceptions. The PROSQOLI linear analog scale was the most responsive measure of pain. Bootstrap confidence intervals for the relative efficiency statistics were wide. CONCLUSIONS: Both the PROSQOLI and the analogous scales from the QLQ-C30 were responsive to improvements in HRQL. Differences between the instruments were generally subtle. The PROSQOLI is a short, simple, responsive measure of HRQL in men receiving systemic treatment for advanced hormone-resistant prostate cancer.

Aged↗

PubMed1998

Effect of exposure to low levels of ozone on the response to inhaled allergen in allergic asthmatic patients.

STUDY OBJECTIVES: In a previous study published by our group, six out of nine subjects with mild allergic asthma were shown to have an enhanced response to allergen challenge following a 1-h exposure in an 0.8-m3 exposure chamber (modified from a body plethysmograph) to an average of 120 parts per billion (ppb) ozone at rest. Other studies failed to confirm this effect. In the present study, using a similar design, we reexamined this effect using a larger group of asthmatics and a larger chamber allowing minimal fluctuations in ozone levels during exposures. DESIGN: Prospective, randomized single-blinded crossover study. SETTING: Pulmonary function laboratory equipped with an exposure chamber. SUBJECTS: Fifteen subjects had mild allergic asthma; 9 men and 6 women; the mean (SD) age was 32.5 (10) years; FEV1 was 3.4 (0.8) L; baseline methacholine provocation concentration causing a 20% fall in FEV1 was (PC20) 3.28 (4.1) mg/mL. INTERVENTIONS: Each participant was exposed, at rest, on 1 day to filtered air and on another day to ozone (mean level=120 ppb) in a larger exposure chamber than the one used in our first study with less variability in ozone level (110 to 130 vs 85 to 175 ppb) using a random, single-blinded design. After each exposure, the subject was challenged with allergen (nine with grass pollen extract and six with ragweed extract) and allergen PC15 was measured. RESULTS: Ozone preexposure did not affect allergen PC15 when compared with clean air preexposure (allergen PC15 dilution 1/114 vs 1/119, respectively). Ozone vs air preexposure resulted in an allergen PC15 that was lower in five subjects, higher in six, and unchanged (within one doubling dose) in four. CONCLUSIONS: At this low level with less variability and lower peaks than our previous study, ozone had no significant effect on airway allergen responsiveness.

Administration, Inhalation↗

PubMed1998

The impact of excluding non-leisure energy expenditure on the relation between physical activity and mortality in women.

The purpose of this study was to examine the relation between physical activity and mortality in a 7-year follow-up of a sample of women more than 30 years of age (N = 6,620) from the Canada Fitness Survey cohort, which was initiated in 1981. Age-adjusted relative risks relating quartiles of average daily energy expenditure (kilocalories per kilogram of body weight per day) to mortality were estimated using logistic regression. Compared with the least active, the risk of all-cause mortality was 0.73 for those in the highest quartile (P for trend = 0.03). The associations were stronger for cardiovascular disease mortality (odds ratio = 0.51; P for trend = 0.01) and fatal myocardial infarction (odds ratio = 0.61; P for trend = 0.04) for those in the highest quartile. These relations were due mainly to the contribution of non-leisure (household chores) energy expenditure, which represented, on average, 82% of women's total activity. The accompanying study on the same cohort by Villeneuve et al reported estimates based on a subset of leisure-time physical activity only, which underestimates the activity of many women (Villeneuve PJ, Morrison HI, Craig CL, Schaubel DE. Physical activity, physical fitness, and risk of dying. Epidemiology 1998;9;632-635). The resulting bias illustrates the importance of including non-leisure energy expenditure in the assessment of total activity. These data support the hypothesis that physical activity is inversely associated with risk of death in women.

Adult↗

PubMed1997

Expectations of life and health among spinal cord injured adults.

While our understanding of aging and mortality in spinal cord injury is evolving, precise estimates are still not available for expectations of life and health following a spinal cord injury. In order to derive these estimates, information about mortality and health must be combined into a single estimate. Health expectancy estimates have been widely used in the literature of the last decade to try to understand the relationship between population health and survival, both in the general population and in special populations. This study brought the benefit of this methodology to the question of long-term survival following spinal cord injury. Specifically, the study aimed to calculate life and health expectancy in a population of spinal cord injured individuals; and to estimate the effect of factors associated with survival and health. The study involved a retrospective cohort, all of whom sustained a spinal cord injury between the ages of 25 and 34 years, and between 1945 and 1990. The study predicted a median survival time of 38 years post-injury, with 43% surviving at least 40 years. These findings suggest an increase in life expectancy of about 5 years over previous research on the same cohort. Factors affecting survival were age at injury, level and completeness of lesion. Expectations of health found in the present study are similar to those found in studies of the general population. This study showed seven remaining years of poor health expected at injury, and five remaining years expected at 40 years post injury, presumably occurring at the end of life.

Adult↗

PubMed1995

A workers' compensation claim population for occupational asthma. Comparison of subgroups.

STUDY OBJECTIVE: (1) To compare patients with claims submitted to the Ontario Workers' Compensation Board (WCB) for occupational asthma, in relation to the WCB decisions reached of occupational asthma (OA); aggravation of asthma from irritant exposures (AA); unrelated asthma; no asthma; and (2) to assess determinants of outcome of WCB accepted claims at permanent disability assessments. DESIGN: A retrospective review of 609 claims submitted to the WCB 1984 to 1988. RESULTS: The WCB decision reached was OA in 39% of claims, mostly attributed to isocyanates (57% of these). A further 39% were accepted for AA. Exposure to a known sensitizer occurred in 91% with OA and to an irritant in 67% with AA. Forty percent with AA were attributed to a spill or accidental exposure and 68% had preceding asthma. Those with AA were more likely to have clearing of symptoms by the time of their main assessment (43% vs 20% with OA) and were more likely to have remained in the same work (35% vs 20% with OA). Of 200 OA accepted claims reviewed at a mean of 1.9 years later, clearing of asthma occurred in 19% and milder asthma in 47%. Outcome was best with early diagnosis (p < 0.05), and milder impairment of pulmonary function at initial assessment (p < 0.05). CONCLUSIONS: Patients with asthma induced by a workplace sensitizer demonstrate some differences from those related to workplace irritants. Accurate categorization and early removal of those with OA offers the best prognosis.

Adult↗

PubMed1993

The apolipoprotein E gene and the serum low-density lipoprotein cholesterol response to dietary fiber.

Our goal was to determine whether differences in apolipoprotein E (apo E) influenced the response to dietary changes aimed at reducing serum cholesterol levels, especially increases in fiber. Apo E phenotype and genotype were determined in 43 men and 24 women who had previously taken part in parallel 2-week metabolic dietary studies involving either wheat bran or oat bran supplementation at a level of 6.8 g fiber/1,000 kcal. Fasting blood lipid measurements had been made at the beginning and end of the 2-week metabolic period. Reductions in low-density lipoprotein (LDL) cholesterol levels across both oat and wheat bran diets were significantly different depending on the E allele (P = .048). The LDL cholesterol level reduction for E2 carriers (0.60 +/- 0.14 mmol/L, n = 13) was greater than that for E3 homozygotes (0.21 +/- 0.07 mmol/L, n = 38; P = .014) and E4 carriers (0.28 +/- 0.12 mmol/L, n = 16; P = .09). Only the change in dietary fiber on the oat bran diet was related significantly to the decrease in LDL cholesterol levels (r = -.47, P = .007; n = 32). No such relationship was seen on the wheat bran diet (r = -.010, P = .59; n = 33). Carriers of the E2 allele appear to be more responsive than noncarriers to a dietary change involving increased fiber intake. The data also support a lipid-lowering advantage of oat bran over wheat bran. Current dietary recommendations to reduce serum lipid levels may vary in effectiveness depending on distribution of apo E alleles in the different populations studied.

Adult↗