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C Janson

Publications and source records attributed to C Janson.

At least 19 recordsLinked to original sources
PubMed2001

Insomnia in men-a 10-year prospective population based study.

STUDY OBJECTIVES: to prospectively analyze changes in the prevalence of insomnia and the relationship between insomnia, aging, lifestyle, and medical disorders DESIGN: a longitudinal population survey. PARTICIPANTS: a randomly selected population sample of 2,602 men (age 30-69 years) from Uppsala in Sweden. INTERVENTION: all participants answered a questionnaire on sleep disturbances, lifestyle factors, and medical disorders in 1984 and again in 1994. MEASUREMENTS AND RESULTS: The prevalence of INSOMNIA was 10.3% in 1984 and 12.8% in 1994. No significant correlation was found between age and insomnia in any of the two time periods. Insomnia in 1994 was independently related to having insomnia in 1984 (OR=6.45), being over-weight (BMI> 27 kg/m2) (OR=1.35), physical inactivity (OR=1.42), alcohol dependence (OR=1.75), psychiatric disorders (OR=8.27) and joint/low back disorders (OR=2.95). The number of subject with reported insomnia in 1984 but not 1994 was 149. Subjects that quit smoking during the time period had an increased likeliness of remission (OR=2.70) while men who were overweight were less likely to remit (OR=0.43). CONCLUSIONS: We conclude that in men insomnia is related to lifestyle factors such as obesity, physical inactivity and alcohol dependency but not to aging. Medical disorders such as joint and low back disorders and psychiatric illnesses also increase the risk of reporting insomnia. This study demonstrates the close relationship between quality of sleep and overall health status.

Adult↗
PubMed2001

Sleep-disordered breathing and glucose metabolism in hypertensive men: a population-based study.

OBJECTIVES: Diabetes mellitus and obstructive sleep apnoea (OSA) are two prevalent medical problems. Both are strongly associated with obesity and hypertension. The aim of this study was to investigate whether the association between OSA and diabetes is entirely dependent on obesity in hypertensive men. DESIGN: A population-based study. SETTING: The municipality of Uppsala, Sweden. Subjects and methods. In 1994, 2668 men aged 40-79 years answered a questionnaire regarding snoring, sleep disturbances and somatic diseases. An age-stratified sample of 116 hypertensive men was selected for a whole-night sleep study. Twenty-five of them had diabetes, defined as reporting regular medical controls for diabetes or having a fasting blood glucose > or =6.1 mmol L(-1). RESULTS: The prevalence of severe OSA, defined as apnoea-hypopnoea index (AHI) > or =20 h(-1) was significantly higher in diabetic patients than in normoglycaemic subjects (36 vs. 14.5%, P < 0.05). The sample was divided into four groups based on the presence or absence of severe OSA and the presence or absence of central obesity, defined as waist-to-hip ratio (WHR) > or =1.0. In a logistic regression model with the non-OSA, WHR <1.0 as the reference group, the adjusted odds ratio (95% confidence interval) for diabetes was 11.8 (2.0-69.8) in the OSA, WHR > or =1.0 group, whilst it was 3.6 (0.9-14.8) in the non-OSA, WHR > or =1.0 group and 5.7 (0.3-112) in the OSA, WHR <1.0 group. In a linear regression model, after adjustment for WHR, there was a significant relationship between variables of sleep-disordered breathing and fasting insulin, glucose and haemoglobin A1c. CONCLUSIONS: We conclude that, in hypertensive men, although obesity is the main risk factor for diabetes, coexistent severe OSA may add to this risk. Sleep breathing disorders, independent of central obesity, may influence plasma insulin and glycaemia.

Adult↗
PubMed2000

Different airway responsiveness profiles in atopic asthma, nonatopic asthma, and Sjögren's syndrome. BHR Study Group. Bronchial hyperresponsiveness.

BACKGROUND: Different mechanisms may underlie bronchial hyperresponsiveness (BHR) in different diseases. The aim of this study was to investigate the bronchial responsiveness profile produced by three different challenge tests, methacholine, a direct stimulus, and two indirect stimuli, adenosine 5'-monophosphate (AMP) and cold air, in subjects with asthma and patients with Sjögren's syndrome. METHODS: The study population comprised 40 adult patients with asthma, 18 subjects with Sjögren's syndrome, and 20 controls. Blood samples were collected before each challenge for measurements of serum eosinophil peroxidase (S-EPO) and eosinophil cationic protein (S-ECP). The investigated subjects recorded peak expiratory flow and kept a symptom diary. RESULTS: Atopic subjects with asthma were significantly more hyperresponsive to AMP than nonatopic subjects with asthma (P=0.01) and subjects with Sjögren's syndrome (P=0.02). No difference was seen between atopic and nonatopic subjects with asthma in the case of challenges with methacholine or cold air. In atopic subjects with asthma, a significant correlation was found between challenges with methacholine and AMP (r=0.91, P=0.0001) and methacholine and cold air (r=0.83, P=0.004), but, in nonatopic subjects with asthma, no significant correlation was seen between methacholine and AMP or cold air challenges. In atopic subjects with asthma, the dose-response slope for AMP was correlated to S-EPO (r= -0.56; P = 0.01) and S-ECP (r= -0.51, P = 0.02), while no correlation between BHR and inflammation markers was found in the two other patient groups. CONCLUSIONS: The results of this study suggest that patients with asthma and subjects with Sjögren's syndrome display different bronchial responsiveness profiles for different challenge agents. Atopic subjects with asthma are more hyperresponsive to AMP than nonatopic subjects and patients with Sjögren's syndrome. More than one challenge may be required to detect different aspects of bronchial responsiveness.

Adenosine Monophosphate↗
PubMed2000

The role of habitual snoring and obesity in the development of diabetes: a 10-year follow-up study in a male population.

OBJECTIVES: There are many similarities between diabetes (mainly type 2) and sleep breathing disturbances regarding risk factors, anthropometric criteria and consequences of morbidity and mortality. The aim of this study was to investigate whether the association between habitual snoring and diabetes is entirely dependent on obesity. DESIGN: A population-based prospective study. SETTING: The municipality of Uppsala, Sweden. SUBJECTS AND METHODS: In 1984 and in 1994, 2668 men aged 30-69 years at baseline answered questionnaires concerning sleep breathing disturbances and somatic diseases. RESULTS: Of those with habitual snoring in 1984, 5.4% reported that they had developed diabetes during the 10-year period compared with 2.4% of those without habitual snoring (P < 0.001). Amongst obese snorers, 13.5% developed diabetes compared with 8.6% of obese non-snorers (P = 0.17). In a multiple logistic regression model, the odds ratio (95% confidence interval) for development of diabetes was higher in obese snorers [7.0 (2.9-16.9)] than in obese non-snorers [5.1 (2.7-9.5)] after adjustment for age, weight gain, smoking, alcohol dependence and physical inactivity. CONCLUSIONS: We conclude that, in males aged 30-69 years, habitual snoring is associated with an increased incidence of diabetes within 10 years. Although obesity is the main risk factor for developing diabetes, coexistent habitual snoring may add to this hazard.

Adult↗
PubMed2000

Reported snoring--does validity differ by age?

Snoring is a major sign of obstructive sleep apnoea syndrome. Despite the frequent number of studies based on subjective reports of snoring, self-reported snoring has hardly been validated at all. In some previous epidemiological studies, a significant association between snoring and cardiovascular morbidity and mortality was found only below the age of 50-60 y. This study was performed to investigate whether this is due to a decrease in the validity of reported snoring with increasing age. In a population-based study, 2668 men aged 40-79 y answered a questionnaire including questions on snoring. Those who reported loud and disturbing snoring often or very often were regarded as habitual snorers. Without taking account of reported snoring, an age-stratified sample of these men was selected and their snoring was measured using a microphone for 1 night. Significant snoring was defined as recorded snoring sounds for >/= 10% of the night. The participants were divided into younger (age 40-59, mean +/- SD: 51.8 +/- 4.6 y, n=132) and older (age 60-79, 67.7 +/- 5.4 y, n=99) age groups. When analysing the validity of reported snoring, no significant differences were found between the younger and older age groups in terms of specificity [younger: 82% (95% CI 74-90%), older: 88% (81-95%)] or sensitivity [younger: 40% (26-54%), older: 35% (17-53%)]. These data indicate that, in men aged 40-79 y, the validity of reported snoring is similar in different age groups. The lack of an association between reported snoring and cardiovascular disease at higher ages can, therefore, not be explained by a decrease in the validity of reported snoring.

Age Factors↗
PubMed2000

What characterizes patients who are unable to tolerate continuous positive airway pressure (CPAP) treatment?

Continuous positive airway pressure (CPAP) is the treatment of choice for obstructive sleep apnoea syndrome (OSAS), but many patients find this treatment intolerable. The aim of this study was to characterize patients who were unable to tolerate CPAP treatment (non-complaint) as opposed to those who continued using CPAP (complaint). A case-control study was performed in which the cases comprised of 40 patients who had been started on CPAP treatment but had found the treatment unacceptable and had ceased to use CPAP. The controls comprised of 63 patients with OSAS who had been prescribed CPAP and were still using it (follow-up period 18 months to 10 yr). The patients who stopped CPAP treatment had a higher mean age, had more frequently undergone uvulopalatopharyngoplasty (UPPP) and had a lower mean oxygen desaturation index (ODI) than patients who continued using CPAP. ODI was an independent negative predictor of non-compliance (OR5units=0.6(0.4-0.8), P<0.01). The two most common reasons for non-compliance were problems in the nose or pharynx and lack of subjective effect by the treatment. High age was an independent risk factor for non-compliance because of problems in the nose or pharynx (OR10years=2.8(1.3-6.1), P<0.01), while having undergone UPPP was a risk factor for non-compliance because of lack of effect (OR=4.5 (1.1-19.1), P<0.05). In conclusion, patients with less severe OSAS are more likely to discontinue CPAP treatment. The risk of experiencing nasal and pharyngeal side-effects of such severity that the patient stops using CPAP increases with age and patients who have undergone UPPP are less likely to experience a clinical improvement after being started on CPAP therapy.

Case-Control Studies↗
PubMed2000

Lung volume and its correlation to nocturnal apnoea and desaturation.

The cross-sectional area of the upper airway is known to be lung volume dependent. If, and to what extent, lung volume variables correlate to nocturnal obstructive apnoeas and oxygen desaturations independently of other factors known to affect lung volumes and sleep disordered breathing is still unclear. A total of 92 subjects were examined by ambulatory recording of nocturnal obstructive apnoeas and desaturations. Sixty-nine of the subjects had a history of snoring and 23 were healthy subjects without complaints of snoring and daytime sleepiness. All subjects performed static and dynamic spirometry for measurements of lung volumes. To evaluate the correlation between lung volume variables and apnoea index (AI) and oxygen desaturation index (ODI), simple and multiple regression analysis was performed. Expiratory reserve volume (ERV) was found to be lower in subjects with snoring and apnoeas (ERV = 1.0 l) than in non-snoring subjects (ERV = 1.7 l), (P<0.001). Forced expiratory volume in 1 sec (FEV1)/vital capacity (VC) was slightly, but significantly (P = 0.031), lower in subjects with snoring and nocturnal apnoeas and desaturations. In the multiple regression analysis ERV was found to be independently correlated to both AI (R2=0.13; P=0.001) and ODI (R2 = 0.11; P = 0.002). Multiple regression analysis also revealed that ERV, body mass index (BMI) and habitual smoking together accounted for 43% of the variation in AI and 48% of the variation in ODI. We find a significant independent association between ERV and nocturnal obstructive apnoea and oxygen desaturation frequency. Our results indicate that ERV is correlated to these events to a similar extent, as is obesity.

Adult↗
PubMed2000

Lung function changes in relation to menstrual cycle in females with cystic fibrosis.

Oestrogen and progesterone have been shown to have impact on cystic fibrosis transmembrane conductance regulator (CFTR) gene expression, tone of smooth muscle in the airways, immune response, exhaled nitric oxide and cytology in the tracheobronchial epithelium. The aim of this investigation was to study the influence of menstrual cyclicity on airway symptoms among cystic fibrosis (CF) females. Twelve CF women (mean age 30 years, mean Shwachman score 85) kept daily records during three menstrual cycles of lung function, sputum quality and need for intravenous antibiotics. Paired t-test was used as a statistical method to compare the airway symptoms between the time of ovulation (high levels of oestrogen and low levels of progesterone), the luteal phase (high levels of oestrogen and progesterone) and menstruation (low levels of oestrogens and progesterone). Forced expiratory volume in 1 sec (FEV1) was significantly higher during the luteal phase (66% of predicted) compared to during ovulation (63%) and menstruation (61%) (P<0.01). Forced vital capacity (FVC) showed the same pattern, being significantly higher during the luteal phase compared with during menstruation (mean 75% vs. 70%, P<0.01). In conclusion, lung function changes were found during menstrual cycles in women with cystic fibrosis. These changes are probably related to changes in progesterone levels during the menstrual cycles. This result warrants further studies to understand the complexity of CF lung disease in women.

Adolescent↗
PubMed2000

Onset and remission of allergic rhinitis and asthma and the relationship with atopic sensitization and smoking.

The aim of this study was to assess the influence of some risk factors for onset and remission of allergic rhinitis and asthma in Swedish adults. A random sample of 1,370 subjects, age 20 to 44 yr was investigated by means of postal questionnaires in 1990 and 1993. Skin prick tests were conducted in 1991-1992. The association between risk factors and onset or remission of allergic rhinitis and asthma was estimated using multivariate logistic regression analysis. Onset of allergic rhinitis was associated with sensitization to birch (odds ratio [OR] = 6.5), Parietaria (OR = 7.4); and pets (OR = 3.0) and with female sex (OR = 1.9). Onset of asthma was associated with allergic rhinitis (OR = 4.9), sensitization to pets (OR = 2.4); and with smoking (OR = 3.0). Onset of asthma was strongly associated with allergic rhinitis among atopics (OR = 5.7), but onset of asthma and rhinitis also tended to be related among nonatopics (OR = 3.5). A strong association between smoking and onset of asthma was found among nonatopics (OR = 5.7). In conclusion, sensitization to pollens and pets were risk factors for onset of allergic rhinitis, whereas allergic rhinitis, sensitization to pets, and smoking were risk factors for onset of asthma.

Adult↗
PubMed2000

Inflammation and structural changes in the airways of patients with atopic and nonatopic asthma. BHR Group.

The aim of the present study was to compare the cellular pattern and structural changes in the airway walls of atopic and nonatopic patients with asthma. Bronchial biopsy specimens were obtained from 13 atopic subjects with asthma, nine nonatopic patients with asthma, and seven healthy control subjects and investigated using immunohistochemical methods. The number of eosinophils increased in both asthma groups, but significantly more in the atopic group. The number of mast cells increased similarly in the two asthma groups, whereas the number of neutrophils increased only in the nonatopic asthma group. The number of T-lymphocytes (CD3-, CD4-, CD8-, CD-25-positive cells) was higher in patients with atopic asthma compared with nonatopic asthma. Interleukin-4 (IL-4) and IL-5-positive cells were more frequently found in the atopic asthma group, whereas cells staining for IL-8 were more frequent in the nonatopic group. The degree of epithelial damage was significantly higher in the atopic asthma group compared with the control subjects and the nonatopic asthmatics. The tenascin and laminin layer was significantly thicker in the atopic group compared with the group of nonatopic asthmatics. In the atopic group, there was a significant negative correlation between epithelial integrity (defined as the relative length of intact epithelium) and the eosinophil count and also between the number of CD25-positive cells and epithelial integrity. The number of mast cells correlated positively with the thickness of tenascin- and laminin-positive layers. In conclusion, we provide evidence of different patterns of involvement of inflammatory cells in atopic and nonatopic patients with asthma. There were also structural differences in the bronchial mucous membrane between atopic asthma and nonatopic asthma. This suggests that there are differences in the extent of the immunopathologic response of these clinically distinct forms of asthma.

Adolescent↗
PubMed1999

Association between atopic sensitization and asthma and bronchial hyperresponsiveness in swedish adults: pets, and not mites, are the most important allergens.

BACKGROUND: Atopic sensitization is a well-known risk factor for asthma and bronchial hyperresponsiveness (BHR). Mites have been regarded as the most important allergens, but the prevalence of sensitization to mites is relatively low in Sweden. OBJECTIVE: The aim of the study was to investigate possible associations between sensitization to various allergens and asthma and BHR in adults. METHODS: A random sample of 1859 subjects, aged 20 to 46 years, was investigated in a cross-sectional study by using a questionnaire, skin prick tests (SPTs), specific and total IgE measurements, and methacholine bronchial challenge tests. Possible associations were analyzed univariately and by using multivariate logistic regression analysis and proportional hazard regression analysis. RESULTS: Positive SPT and specific IgE results were more common in subjects with asthma and BHR than in subjects without these conditions for all allergens. The independent associations between positive SPT responses and asthma and BHR are given as adjusted prevalence ratios (PRRs): pets and asthma, PRR = 3.6; pets and BHR, PRR = 2.0; grass and asthma, PRR = 2.0; grass and BHR, PRR = 1.7; mites and asthma, PRR = 1.4; and mites and BHR, PRR = 1.2. The use of specific IgE measurements instead of SPTs showed essentially similar results. CONCLUSION: Cats and dogs were the sensitizing allergens most closely associated with asthma and BHR. The relationships with sensitization to grass and mites were less pronounced.

Adult↗
PubMed1999

Inflammatory markers in acute exacerbations of obstructive pulmonary disease: predictive value in relation to smoking history.

The aim of this study was to investigate the relationship between the effect of emergency treatment and inflammatory markers in patients with acute exacerbations of obstructive pulmonary disease, especially with respect to smoking history. We investigated 50 unselected patients with acute bronchial obstruction. Blood, urine and sputum samples were taken and analysed for eosinophil and neutrophil markers. The patients were observed for at least 2 h and recordings of forced expiratory volume in 1 s (FEV1) were taken. They were re-examined after 1 and 4 weeks. The absolute levels of inflammatory markers did not differ significantly between non- or short-term smokers (< or = 5 pack-years) and long-term smokers (> 5 pack-years) with the exception of myeloperoxidase in serum (S-MPO), which was higher in long-term smokers. The patients with higher levels of eosinophil markers before emergency treatment experienced a greater improvement in lung function. In non- or short-term smokers this relationship was found in blood and urine, whereas in long-term smokers it was seen in sputum. No correlation was found between neutrophil markers and changes in lung function. We conclude that patients with obstructive pulmonary disease with acute exacerbations and high levels of eosinophil markers respond well to treatment.

Acute Disease↗
PubMed1999

Exhaled nitric oxide and its relationship to airway responsiveness and atopy in asthma. BHR-Study Group.

Exhaled nitric oxide (NO) has attracted increasing interest as a non-invasive marker of airway inflammation. The purpose of this study was to determine whether exhaled nitric oxide in subjects with asthma varied according to their atopic status and to examine its correlation with airway hyperresponsiveness and lung function measurements. Forty patients with asthma and 13 controls participated in the study. Nitric oxide was measured on three occasions with intervals of at least 3 days, using a chemiluminescence method. Airway responsiveness was assessed with methacholine challenge and lung function measurements were made. All subjects recorded peak expiratory flow and kept a symptom diary during a 17-day period. There was no significant difference in lung function measurements, peak expiratory flow or symptom score between the two asthma groups. Atopic patients with asthma had a significantly higher mean amount of exhaled NO than non-atopic subjects with asthma (162 +/- 68 vs. 113 +/- 55 nl min-1; P = 0.03) and the control group (88 +/- 52 nl min-1; P = 0.004). No significant difference was found in the amount of exhaled NO between non-atopic patients with asthma and the controls. In atopic subjects with asthma the mean exhaled NO was significantly correlated to the dose-response slope for methacholine (r = -0.52; P = 0.02), while no such correlation was found in the non-atopic group. In conclusion; in this study, atopic subjects with asthma had higher levels of exhaled NO than non-atopic subjects. Atopic status should be taken into account when measuring levels of exhaled NO in subjects with asthma.

Adolescent↗
PubMed1999

Sensitization to airborne and food allergens in Reykjavík (Iceland) and Uppsala (Sweden) - a comparative study.

BACKGROUND: The aim of this study was to compare the prevalence of atopic sensitization and possible risk factors for allergies in two ethnically similar but geographically widely separated urban populations. METHODS: Data from two centers of the European Community Respiratory Health Survey, Reykjavik, Iceland, and Uppsala, Sweden, were utilized. This included a structured interview, skin prick tests, and blood samples for total and specific IgE for common aeroallergens. Additional measurements of specific IgE antibodies to common food antigens were performed. Furthermore, data on social environment, lifestyle, air pollution, and meteorologic variables were compared. RESULTS: Skin prick tests were done on 540 individuals in Reykjavik and 527 in Uppsala. The overall prevalence of at least one positive prick test was 20.5% in Reykjavik and 34.2% in Uppsala (P<0.001). Total and specific IgE were measured in serum from 521 subjects in Reykjavik and 472 in Uppsala. The geometric mean value for total IgE was significantly lower in Reykjavik (13.4 kU/l) than in Uppsala (24.7 kU/l) (P<0.001). Similarly, the overall prevalence of at least one specific IgE to airborne allergens was 23.6% in Reykjavik and 32.3% in Uppsala (P<0.01). Specific IgE to a food panel (fx5) was measured in 502 subjects in Reykjavik, and 434 in Uppsala. In Reykjavik, 20 individuals (4.0%) were positive to one or more of the allergens in the food panel compared to 27 (6.0%) in Uppsala. When the single allergens present in the food panel were measured, altogether 16 positive reactions were found in Reykjavik compared to 47 in Uppsala (P<0.05). CONCLUSIONS: The prevalence of sensitization to both airborne and food allergens was lower in Reykjavik than in Uppsala. The difference may be due to environmental and/or dietary differences or to some yet undefined factor.

Adult↗
PubMed1999

Adult asthmatics sensitized to cats and dogs: symptoms, severity, and bronchial hyperresponsiveness in patients with furred animals at home and patients without these animals.

BACKGROUND: Domestic furred animals are important sources of allergens in asthma, but few clinical studies have investigated the effects of exposure to or elimination of these allergens. The objective of this study was to investigate whether pet-sensitized asthmatics with pets at home have worsened asthma, compared with similar asthmatics without pets. METHODS: In a cross-sectional epidemiologic study, 129 adult asthmatics sensitized to cats or dogs were investigated by interviews, skin prick tests, specific IgE, eosinophil counts, and bronchial methacholine challenge tests. Patients with a cat or dog at home (n=39) were compared with subjects without pets (n=90). RESULTS: More subjects with pets had symptoms, inhaled or oral steroids, abnormal peak-flow records, higher eosinophil counts, and a higher degree of bronchial hyperresponsiveness than subjects without pets. Asthmatics with pets more frequently ascribed their symptoms to their home environment, but fewer of them reported that their symptoms were elicited by contact with cats or dogs. CONCLUSIONS: This study strongly indicates that living with a cat or a dog aggravates symptoms and biomarkers of airway inflammation in asthmatics sensitized to cats or dogs. The study indicates that avoidance of these allergens may be an important measure in the treatment of sensitized asthmatics.

Adolescent↗
PubMed1999

Increased nitric oxide in expired air in patients with Sjögren's syndrome. BHR study group. Bronchial hyperresponsiveness.

Nitric oxide has an important role in the regulation of airway function and can have pro-inflammatory effects. Bronchial hyperresponsiveness (BHR) and respiratory symptoms are common in patients with Sjögren's syndrome (SS). The aim of this study was to determine whether patients with SS have an increased amount of exhaled NO and whether this NO correlates with respiratory symptoms and BHR. Exhaled NO was measured in 18 patients with SS and 13 normal subjects on three different occasions with intervals of at least 3 days using a chemiluminescence method. Airway responsiveness was assessed with methacholine provocation. Serum levels of myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) were measured. Exhaled NO was significantly higher in patients with SS than in controls (147+/-82 versus 88+/-52 nL x min(-1); mean+/-SD; p=0.041). Exhaled NO was correlated with age (partial r=0.52, p=0.006) and serum HNL (partial r=0.46, p=0.014). There were no significant correlations between exhaled NO and respiratory symptoms, BHR or serum MPO, ECP or EPO. Disease duration was negatively associated with serum MPO (r=-0.47, p=0.043). In patients with SS, a positive correlation was found between symptom score and serum ECP (partial r=0.65, p=0.003) and EPO (partial r=0.62, p=0.004) and a negative correlation with age (partial r=-0.60, p=0.005). In conclusion, elevated levels of exhaled nitric oxide in patients with Sjögren's syndrome were demonstrated. The mechanism underlying this increase in exhaled nitric oxide in Sjögren's syndrome is not known.

Breath Tests↗
PubMed1999

Comparison of two methacholine challenge methods using Spira-2 or Mefar dosimeter.

Two bronchial challenge protocols with breath-actuated dosimeters, Spira Elektro-2 and Mefar, with similar cumulative dose steps were compared in 28 patients with mild to moderate asthma. Methacholine challenges were performed after two different protocols at the same time of day in random order 3 or 4 days apart. The provocative dose of methacholine producing a 20% fall in forced expiratory volume in 1 second (PD20) was lower when determined by Spira than with the Mefar dosimeter (P < 0.05). Transition equations calculated by linear regression analysis were: PD20mefar = exp10[0.897 + 0.678(logPD20spira)] (P < 0.05; r = 0.62) and PD20spira = exp10[0.759 + 0.559 (log PD20mefar)] (P < 0.05; r = 0.62). The slopes were calculated by regressing the percentage fall in FEV1 on log10 (dose) and transformed as slope = 100/(regression coefficient + 10). The mean slope (95% CI) for Spira was 3.1 (2.6-3.7) and for Mefar 4.4 (3.6-5.1) (P < 0.005). Regression equations calculated by linear regression analysis were: slope(mefar) = 2.126 + 0.712 slope(spira) (P < 0.05; r = 0.51) and slope(spira) = 1.551 + 0.365 slope(mefar) (P < 0.05; r = 0.51). In conclusion, PD20 was smaller and the decline in FEV1/log(dose) curve steeper using the Spira compared with the Mefar protocol. The dose-response curves should be validated and transition equations calculated when bronchial reactivity to inhaled agents is compared, even while using apparently similar well-standardized dosimeter methods.

Adolescent↗