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.

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.

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.

IgE-mediated allergy to Lepidoglyphus destructor in an urban population--an epidemiologic study

BACKGROUND

The aim of this study was to estimate the prevalence of IgE-mediated allergy to Lepidoglyphus destructor and its clinical importance in Reykjavik, Iceland.

METHODS

All Icelandic participants in the European Community Respiratory Health Survey in Reykjavik and suburbs were skin prick tested (SPT) for L. destructor. They also participated in a structured interview including questions about exposure to hay and symptoms related to hay exposure. Spirometry and methacholine tests were also performed.

RESULTS

Altogether, 540 individuals underwent SPT with 12 allergens. Among them, 137 (25.4%) had positive skin tests, defined as at least one mean wheal reaction of > or =1 mm. By this definition, 34 (6.3%) were positive to L. destructor. These 34 individuals were significantly (P < 0.001) more often allergic to D. pteronyssinus (24/34), grass (14/34), cat (13/34), dog (12/34), Alternaria (11/34), Cladosporium (9/34), horse (8/34), and olive (8/34) than those not allergic to L. destructor. Those SPT positive to L. destructor had a higher total IgE (geometric mean: 40.9 kU/I vs 12.3 kU/I, P < 0.001) than those who were negative to L. destructor, but their lung function was comparable to that of the others. Asthma during the preceding 12 months or asthma ever suffered was not overrepresented among those SPT-positive to L. destructor. Individuals with symptoms associated with hay exposure were more often SPT positive to L. destructor than those not having symptoms (P < 0.01).

CONCLUSIONS

In a random urban population, 6.3% showed IgE-mediated allergy to L. destructor. These were often polysensitized atopics with a high prevalence of clinical symptoms associated with exposure to hay.

Evolution of sleep apnea syndrome in sleepy snorers: a population-based prospective study

This study followed a small number of men previously studied polysomnographically 10 yr earlier to investigate the relationship between the development of sleep-disordered breathing and age, weight gain, and smoking. In 1984, 3,201 men answered a questionnaire including questions about snoring and excessive daytime sleepiness (EDS). Of those reporting symptoms related to obstructive sleep apnea syndrome (OSAS), a random sample of 61 men was investigated using whole-night polysomnography in 1985. Ten years later, 38 men participated in the present follow-up, which included a structured interview and polysomnography. During the 10-yr period, nine men had been treated for OSAS. Of the 29 untreated subjects, the number of men with OSAS, defined as an apnea-hypopnea index (AHI) of >/= 5/h, increased from four in 1985 to 13 in 1995 (p < 0.01). In this small sample, no significant associations were found between DeltaAHI (i.e., AHI 1995 - AHI 1985) and age, weight gain, or smoking. We conclude that, among this small group of individuals who were selected for original polysomnographic study and follow-up because they were thought to have symptoms of sleep apnea, sleep-disordered breathing became significantly worse over time.

Chronic bronchitis in Icelandic males: prevalence, sleep disturbances and quality of life

OBJECTIVE

To study the prevalence of chronic bronchitis in Iceland and some aspects of quality of life among those suffering from chronic bronchitis.

DESIGN

Postal questionnaires. SETTING, SUBJECTS: All Icelandic males born in the years 1913 and 1943 who were alive on 1 November 1993. Altogether 1175 (69.7%) responded.

MAIN OUTCOME MEASURES

Physical symptoms of chronic bronchitis, stress symptoms, symptoms of dyspnea and sleep disturbances.

RESULTS

7.1% of those 50 years old and 16.7% of those 80 years old and a history of daily sputum expectoration for at least 3 months during the preceding 2 years. These individuals with chronic bronchitis had a higher prevalence of other respiratory symptoms than did the others, such as "wheezing or whistling" (59.6% vs. 7.2%), and "awakened by breathlessness" (35.2% vs. 6.0%). Complaints of dyspnea were more common among those with symptoms of chronic bronchitis, e.g. "dyspnea when walking" (19.4% vs. 1.4%) and "stops walking because of dyspnea" (22% vs. 1.6%). They also complained more often of insomnia and daytime sleepiness and found themselves more stressed than those without chronic bronchitis. These symptoms were all more common among the 80-year-old men.

CONCLUSION

Our study indicates that chronic bronchitis is a frequent illness among Icelandic males. Men with chronic bronchitis often have decreased quality of life, difficulties in moving and frequently sleep complaints.

A 10-year follow-up of snoring in men

STUDY OBJECTIVES

Little is known about the natural development of snoring, and this survey was conducted to study the development of snoring in men over a 10-year period.

DESIGN

Population-based prospective survey.

SETTING

The Municipality of Uppsala, Sweden.

PARTICIPANTS AND MEASUREMENTS

In 1984, 3,201 randomly selected men aged 30 to 69 years answered a questionnaire on snoring and sleep disturbances. Of the 2,975 survivors in 1994, 2,668 (89.7%) answered a new questionnaire with identical questions to those used at baseline. Questions about smoking habits, alcohol, and physical activity were also added.

RESULTS

Habitual snoring was reported by 393 men (15.0%) in 1984 and by 529 (20.4%) 10 years later. In both 1984 and 1994, the prevalence of snoring increased until age 50 to 60 years and then decreased. Risk factors for being a habitual snorer at the follow-up were investigated using multiple logistic regression with adjustments for previous snoring status, age, body mass index (BMI), weight gain, smoking habits, and physical activity. In men aged 30 to 49 years at baseline, the predictors of habitual snoring at the follow-up, in addition to previous snoring status, were as follows: persistent smoking (adjusted odds ratio, 95% confidence interval) (1.4, 1.1 to 1.9), BMI 1984 (1.1, 1.02 to 1.1/kg/m2) and weight gain (1.1, 1.03 to 1.2/kg/m2). Among men aged 50 to 69 years, after adjustments for previous snoring status and age, weight gain was the only significant risk factor for developing habitual snoring (1.2, 1.05 to 1.4/kg/m2).

CONCLUSIONS

In men, the prevalence of snoring increases up to the age of 50 to 60 years and is then followed by a decrease. Weight gain is a risk factor for snoring in all age groups, while smoking is mainly associated with snoring in men <60 years of age.

Increased mortality among sleepy snorers: a prospective population based study

BACKGROUND

The long term health consequences of snoring and sleep apnoea syndrome are still uncertain. This study was conducted to assess the mortality risk associated with snoring and excessive daytime sleepiness (EDS), the two main symptoms of sleep apnoea syndrome, in men.

METHODS

In 1984 a sample of 3100 men aged 30-69 responded to a postal questionnaire including questions about snoring, EDS, and the prevalence of various diseases (response rate 77.1%). Mortality data for the period 1985-1995 were collected for the complete sample.

RESULTS

During the 10 year follow up period 213 men died, 88 of cardiovascular diseases. Compared with subjects with no snoring or EDS in 1984, men with isolated snoring or EDS displayed no significantly increased mortality. The combination of snoring and EDS was associated with a significant increase in mortality. However, the relative rates decreased with increasing age, and in men aged 60 and above no effect on mortality was found. Men below the age of 60 with both snoring and EDS had an age adjusted total death rate which was 2.7 times higher than men with no snoring or EDS (95% CI 1.6 to 4.5). The corresponding age adjusted hazard ratio for cardiovascular mortality was 2.9 (95% CI 1.3 to 6.7) for subjects with both snoring and EDS. Further adjustment for body mass index and reported hypertension, cardiac disease, and diabetes reduced the relative mortality risk associated with the combination of snoring and EDS to 2.2 (95% CI 1.3 to 3.8) and the relative risk of cardiovascular mortality to 2.0 (95% CI 0.8 to 4.7).

CONCLUSION

Snoring without EDS does not appear to carry an increased risk of mortality. The combination of snoring and EDS appears to be associated with an increased mortality rate, but the effects seems to be age dependent. The increased mortality is partly explained by an association between "snoring and EDS" and cardiovascular disease.

Snoring and hypertension: a 10 year follow-up

In many cross-sectional studies an association has been found between snoring and hypertension. However, differing results have been obtained when confounding factors have been taken into account. To establish whether snoring is a risk factor for developing hypertension, a population-based, prospective survey was performed. In 1984 and 1994, 2,668 males, aged 30-69 yrs at baseline, answered questionnaires concerning sleep disturbances and somatic disease. Of the habitual snorers in 1984, 12.5% reported that they had developed hypertension during the period, compared with 7.4% of the remaining subjects (p<0.001). In a multiple logistic regression model persistent snoring, i.e., reported habitual snoring in both 1984 and 1994, was found to be an independent predictor for the development of hypertension among males aged 30-49 yrs (odds ratio 2.6, 95% confidence interval 1.5-4.5) after adjustments for age, body mass index (BMI), weight gain, smoking, alcohol dependence, and physical inactivity. Among the subjects aged 50-69 yrs in 1984, no association between snoring and development of hypertension was found. Although based only on reported data, the results indicate that persistent snoring is an independent risk factor for the development of hypertension among males aged <50 yrs. Prospective surveys, including whole-night sleep recordings, are needed to establish whether this is due to a higher prevalence of obstructive sleep apnoea syndrome among snorers or whether nonapnoeic snorers with increased upper airway resistance also have an increased risk of developing hypertension.

[Allergic and pseudo-allergic reactions to drugs in an Icelandic urban population 20-44 years of age.]

OBJECTIVE

Allergic or pseudo-allergic reactions to drugs are common complaints. The symptoms vary from mild to life threatening. Although the mechanisms for most drug reactions are unknown or uncertain such reactions are believed to be more common among atopic individuals. Our goal was: 1) To estimate the prevalence of allergic and pseudo-allergic drug reactions in a random urban Icelandic population 20-44 years of age. 2) To search for the characteristics of symptoms and which drugs were involved in such reactions, 3) their association to atopy and atopic diseases and 4) to find possible risk factors.

MATERIAL AND METHODS

In the second stage of the European Community Respiratory Health Survey an urban population 20-44 years of age was invited to participate. In Iceland altogether 545 answered an additional question: Have you at any time had allergic reaction to drugs? Those who answered yes to this question were contacted later by telephone and asked further about drug allergy.

RESULTS

Altogether 77 (14%) replied yes to the question, more females (19%) than males (9%) (p<0.001). Atopic individuals (with one or more positive prick tests) and those with nasal allergies, eczema, urticaria and illness caused by eating a particular food or foods reported allergic drug reactions more often (p<0.05). IgE geometric mean value was 17.5 kU/L for those who reported allergic drug reaction compared to 12.6 kU/L among the others (p=0.08). The most common symptoms associated with drugs were skin symptoms (urticaria, angioneurotic edema), symptoms from respiratory organs and fever. With further inquiries by telephone 13/64 denied drug allergy. Thus 51/64 (80%) withheld their questionnaire answers. Antibiotics were most often blamed for drug reactions, followed by anaesthetics, NSAID and opiates.

CONCLUSION

There was a correlation between reported drug reactions and atopy and/or atopic diseases. The drug reactions were more than twice as common in women as in men. The only comparable study we know of, shows the prevalence of drug reactions on the same level as in Iceland.

Users of antiasthma drugs in Iceland: a drug utilization study

There has been an increasing consensus worldwide on how to treat asthma, and, simultaneously, an increase in the sales of antiasthma drugs. However, little is known about actual drug use, dosage, combinations of drugs, etc., or about the clinical characteristics of patients using these drugs. All individuals with prescriptions for antiasthma drugs, who came to Icelandic pharmacies during March 1994, were invited to participate. By means of questionnaires, the pharmacists recorded the age and gender of the patient, the specialty of the prescribing doctor, as well as the name of the drug, total amount prescribed, and dosage. The patients were asked to answer another questionnaire on their clinical diagnosis, usage of other antiasthma drugs, etc. The pharmacists registered 2,026 individuals, with 2,687 prescriptions: 1,574 for beta2-agonists, 838 for inhaled corticosteroids, 208 for theophylline, 48 for anticholinergic drugs, and 19 for cromoglycates. One thousand, three hundred and fifty one patients answered the questionnaires. The majority (67%) claimed to have asthma, 18% chronic bronchitis, 11% emphysema and 5% other diseases or symptoms. Among those aged > or = 16 yrs with asthma, 93% used beta2-agonists, 62% inhaled corticosteroids, 19% theophylline, and very few used other drugs. The most commonly used combination (57%) was beta2-agonists with inhaled corticosteroids. Thirty one per cent used beta2-agonists as monotherapy, and 5% used only inhaled corticosteroids. Theophylline was used mainly in combination with beta2-agonists and inhaled corticosteroids. In conclusion, our data suggest that two thirds of antiasthma drug users have asthma and that most are treated according to present guidelines. The use of inhaled corticosteroids, however, seems somewhat less than optimal.

Sleep disturbances in a young adult population: can gender differences be explained by differences in psychological status?

To study the prevalence of reported sleep disturbances and the association between these complaints and psychological status, 529 randomly selected subjects aged 20-45 years were questioned about their sleep symptoms and psychological status by means of questionnaires. In this young population, feeling refreshed in the morning almost every day was reported by only 15.3%. Females reported a significantly longer mean total sleep time (TST) than males (F: 425 +/- 58 minutes, M: 403 +/- 50 minutes; p < 0.01). Despite this, the difference compared with the reported need of sleep was greater in females (56 +/- 62 minutes) than in males (40 +/- 51 minutes) (p < 0.05). Difficulties maintaining sleep (DMS, > or = 3/week) (F: 20.1%, M: 10.4%; p < 0.01), the absence of feeling refreshed in the morning (F: 36.2%, M: 26.8%; p < 0.05), and excessive daytime sleepiness (EDS) (F: 23.3%, M: 15.9%; p < 0.05) were significantly more common among females. According to the Hospital Anxiety and Depression scale, females suffered from anxiety more frequently than males (F: 32.8%, M: 18.9%; p < 0.001). An association was found between anxiety and many sleep disturbances. After making adjustments for age, smoking, snoring, gender and psychological status by means of multiple regression, the gender differences mentioned above remained significant. We conclude that despite a longer TST, females report insufficient sleep, EDS, DMS, and the absence of feeling refreshed in the morning more frequently than males. The higher prevalence of anxiety among females alone cannot explain the gender differences in sleep disturbances seen in this population.

[Bronchial asthma and respiratory symptoms among Icelanders 20-44 years of age.]

OBJECTIVE

To estimate the prevalence of asthma and respiratory symptoms in an urban population.

MATERIAL

Eight hundred men and women aged 20-44 years, living in the capital Reykjavik and suburbs.

METHODS

Participants answered a questionnaire, underwent skin prick testing for atopy, spirometry and a test for bronchial hyperresponsiveness (BHR) by methacholine challenge.

RESULTS

There was 77% attendance. Altogether 16.6% reported wheezing or whistling at any time in the last 12 months. Altogether 32 (5.6%)answered yes to "Have you ever had asthma?" and the diagnosis had been confirmed by a doctor in all but four. Fourteen (2.5%) had suffered from an attack of asthma in the last 12 months wheras only 0.9% were currently using anti asthmatic drugs. BHR was found among 8.7% and atopy on skin testing among 20.5%. BHR was more common among those with airflow obstruction and three times more common among the atopic participants (18% vs. 6%, p%lt;0.01). By using a history of wheezing during the last 12 months together with BHR and/or a history of doctor confirmed asthma the prevalence of current asthma was found to be 5% in our sample. The main predictive factors for asthma were a history of breathlessness and nighttime breathing symptoms, but also atopy, airflow obstruction and a maternal history of asthma.

CONCLUSION

Even by using a conservative defination, asthma is a common disorder among 20-44 years old Icelanders whereas the use of asthma medication is rather uncommon in this population.

Long-term follow-up of patients with obstructive sleep apnea treated with uvulopalatopharyngoplasty

OBJECTIVE

To study the long-term outcome after treatment with uvulopalatopharyngoplasty (UPPP).

DESIGN

Long-term follow-up (4-8 years) with polysomnography.

SETTING

Referral center for patients with sleep-disordered breathing.

PATIENTS

Thirty-four consecutive patients of whom 25 (22 men and 3 women; mean age, 49 years) participated in the follow-up. All patients had obstructive sleep apnea syndrome.

INTERVENTION

Uvulopalatopharyngoplasty.

MAIN OUTCOME MEASURES

Symptoms and apnea-hypopnea index (AHI) before and after UPPP. Response to treatment defined as a 50% or more reduction in AHI and a postoperative AHI of 10 or less.

RESULTS

Reduced prevalence of snoring and daytime sleepiness and reduction in AHI (mean [+/-SD], 40 +/- 26 to 21 +/- 21) at follow-up (P < .001). Sixteen patients (64%) were responders after 6 months and 12 (48%) at the long-term follow-up. Responders had a lower preoperative AHI (25 +/- 7) than did nonresponders (48 +/- 29) (P < .05). None of the 7 patients with preoperative AHI of more than 40 were responders (P < .01). No difference was seen in preoperative body mass index, lung function, ventilatory response to carbon dioxide, computed tomography scan of upper airways, or change in body mass index between responders and nonresponders.

CONCLUSIONS

Four to 8 years after UPPP, about half of our patients were clinically and objectively improved. Uvulopalatopharyngoplasty should be reserved for patients with mild or moderate obstructive sleep apnea. After UPPP, long-term follow-up is recommended because some initially successfully treated patients will relapse in the long term.

Medical risk factors amongst drivers in single-car accidents

OBJECTIVES

To estimate medical risk factors amongst drivers in single-car accidents with special reference to sleepiness and alcohol abuse.

DESIGN

An epidemiological survey by means of multiple-choice questionnaires that were mailed to drivers and a random control group.

SETTING

Iceland.

SUBJECTS

All drivers in single-car accidents (n = 471) during 1989-91 and a control group from the general population (n = 1000).

MAIN OUTCOME MEASURE

Medical health profile and answers to questions concerning sleep disorders and alcohol abuse.

RESULTS

Compared to the controls the drivers were younger and there were three times more males. The drivers abused alcohol more often. Chronic disorders such as epilepsy, diabetes mellitus, and cardiac disorders were not over-represented. Altogether, 15.4% claimed that sleepiness had caused their traffic accident, logistic regression analyses revealed that these 'sleepy' drivers more often had alcohol abuse and a history of 'almost falling a sleep whilst driving'.

CONCLUSIONS

Compared to controls, drivers in single-car accidents are more likely to be young, male, have a history of sleepiness whilst driving, and also have a history suggestive of alcoholism. Chronic disorders like epilepsy and diabetes mellitus were not over-represented amongst the single-car accidents drivers. These results raise the question of how drivers with a high probability of causing an accident (sleepiness and alcoholism) can be identified in time and proper measures taken to prevent 'accidents waiting to happen'.

[Can finasteride reverse the progress of benign prostatic hyperplasia? A two-year placebo-controlled study.]

OBJECTIVE

To study if placebo-induced improvement in men with symptomatic benign prostatic hyperplasia (BPH) is maintained over two years, and to study the efficacy and safety from intervention with finasteride 5 mg for 24 months.

METHODS

This was a multicenter, double-blind, placeba-controlled study involving 707 patients with moderate symptoms of BPH enrolled at 59 centers in five Scandinavian countries. Following enrollment and a four-week single-blind placebo run-in period, patients were randomized to receive finasteride 5 mg once daily or placebo for 24 months. Urinary symptoms, urinary flow rate, prostate volume, postvoiding residual urinary volume, and serum concentrations of prostate-specific antigen together with laboratory safety parameters were measured at entry and at months 12 and 24. Interim physical and laboratory examinations were performed when indicated clinically.

RESULTS

In finasteride-treated patients the total symptom score improved throughout the study, with a significant difference between the two groups at 24 months (p<0.01) whereas in placebo-treated patients, there was an initial improvement in the symptom score but no change from baseline at 24 months. The maximum urinary flow rate decreased in the placebo group, but improved in the finasteride group, resulting in a between-group difference of 1.8 mL/s at 24 months (p<0.01). The mean change in prostate volume was +12% in the placebo group versus -19% in the finasteride-treated group (p%lt;0.01). Finasteride was generally well tolerated throughout the two-year study period.

CONCLUSIONS

The efficacy of therapy with finasteride 5 mg in improving both symptoms and maximum urinary flow rate and reducing prostate volume has been shown to be maintained during 24 months while patients receiving placebo experienced a return to baseline or deterioration of these parameters during the study. These results demonstrate that finasteride can reverse the natural progression of BPH.

Increased prevalence of sleep disturbances and daytime sleepiness in subjects with bronchial asthma: a population study of young adults in three European countries

The aim of this study was to investigate whether asthma is associated with decreased quality of sleep and increased daytime sleepiness. The study involved a random population of 2,202 subjects supplemented by 459 subjects with suspected asthma, aged 20-45 yrs. The subjects were from Reykjavik (Iceland), Uppsala and Göteborg (Sweden) and Antwerp (Belgium), and participated in the European Community Respiratory Health Survey. The investigation included a structured interview, methacholine challenge, skinprick tests and a questionnaire on sleep disturbances. Participants in Iceland and Sweden also estimated their sleep times and made peak expiratory flow (PEF) recordings during a period of 1 week. Asthma was defined as self-reported physician-diagnosed asthma with current asthma-related symptoms (n = 267). Difficulties inducing sleep (DIS) and early morning awakenings (EMA) were about twice as common, and daytime sleepiness 50% more common, in asthmatics compared with subjects without asthma. After adjusting for possible confounders, a positive association was found between asthma and: DIS (odds ratio (OR) = 1.8); EMA (OR = 2.0); daytime sleepiness (OR = 1.6); snoring (OR = 1.7); and self reported apnoeas (OR = 3.7). Allergic rhinitis, which was reported by 71% of subjects with asthma, was independently related to DIS (OR = 2.0) and daytime sleepiness (OR = 1.3). A significant correlation was found between the number of asthma-related symptoms and sleep disturbances (p < 0.001). Asthma is associated with decreased subjective quality of sleep and increased daytime sleepiness. Concurrent allergic rhinitis may be an important underlying cause of sleep impairment in asthmatic patients.

[Chronic bronchitis among 50 and 80 years old males in Iceland. Prevalence and quality of life.]

OBJECTIVE

The mortality from chronic bronchitis has been increasing in Iceland during the last decades. Little is however known about the prevalence of this disease and the objective of this study was to find the prevalence of chronic bronchitis in Iceland.

MATERIAL AND METHODS

In this study a postal questionnaire was sent to all Icelandic males born in the years 1913 (N=388) and 1943 (N=1297) who were alive on the 1st November 1993, asking about several physical symptoms, including symptoms of chronic bronchitis. The response rate was 69.7%.

RESULTS

Altogether 7.1% of 50 years old males and 16.7% of 80 years old males had a history of daily sputum expectoration for at least three months during the last two years. These individuals with chronic bronchitis had a higher prevalence of other respiratory symptoms, such as coughing, wheezing or whistling. History of dyspnea was much higher among those with symptoms of chronic bronchitis. They also complained more often of sleep disturbances and found themselves more stressed than those without symptoms of chronic bronchitis.

CONCLUSION

Our study indicates that chronic bronchitis is a frequent illness among Icelandic males. Men with chronic bronchitis frequently have a decreased quality of life, difficulties to move and frequently sleep complaints.

[Antiasthmatic drugs in Iceland - an epidemiological survey.]

The use of antiasthmatic drugs in Iceland has increased considerably during the last 15 years. The aim of this study was to assess in a well-defined epidemiological population the characteristics of those using antiasthmatic drugs; age, gender, speciality of prescribing doctor, dosage and combinations of drugs. Also their clinical diagnosis and symptoms. All individuals with prescriptions for antiasthmatic drugs that came to Icelandic pharmacies during March 1994 were invited to participate. Altogether 2026 individuals accepted (2687 prescriptions). There were proportionally more young males and middle aged females (p<0.0001). The prescriptions for beta2-adrenergic drugs were 1574, 838 for inhaled corticosteroids, 208 for theofylline, 49 for anticholinergic drugs and 19 for natrium chromoglycate. General practitioners had prescribed 68% of the drugs, 16.3% were from pulmonary physicians and/or allergists, 6.4% from pediatricians and 9.3% from other doctors. The treatment had been started by specialists other than general practitioners in more than 60% of cases. Among those using inhaled drugs 95% had been tought how to do so. The majority (66.9%) claimed that they were using the drugs because of asthma, 17.8% because of chronic bronchitis, 10.7% because of emphysema and 4.6% for other reasons. There were altogether 591 individuals (2=16 years) with asthma who answered the questionnaire. Among them 93% used beta2-adrenergic drugs, 62% inhaled corticoseroids, 19% theofylline and very few used other drugs. The most commonly used combination (57%) was beta-adrenergic drugs and inhaled corticoseroids. Altogether 31% used beta2-adrenergic drugs as monotherapy and 5% had only inhaled corticosteroids. Theofylline is mainly used in combination with beta-adrenergic drugs and inhaled corticosteroids. Its use as monotherapy is infrequent (2%). Among those 209 asthma patients who had used oral corticosteroids the last 12 months, 73% were using some kind of inhaled corticosteroids and 27% not.

Prevalence of sleep disturbances among young adults in three European countries

The aim of this investigation was to study the geographic variation in sleep complaints and to identify risk factors for sleep disturbances in three European countries: Iceland (Reykjavik), Sweden (Uppsala and Göteborg) and Belgium (Antwerp). The study involved a random population of 2,202 subjects (age 20-45 years) who participated in the European Community Respiratory Health Survey. The subjects answered a questionnaire on sleep disturbances. Participants in Iceland and Sweden also estimated their sleep habits and sleep times during a period of 1 week in a sleep diary. Habitual (> or = 3/week) difficulties inducing sleep (DIS) were reported by 6-9% and early morning awakenings by 5-6% of the subjects. The estimated number of awakenings and the prevalence of nightmares was significantly lower in Reykjavik. Participants in Reykjavik went to bed at night and woke in the morning approximately 1 hour later than participants at the Swedish centers (p < 0.001). Symptoms of gastroesophageal reflux (GER) were associated with DIS (odds ratio [OR] = 2.7), nightmares (OR = 4.4), longer sleep latency and frequent nocturnal awakenings. Smoking correlated positively to DIS (OR = 1.8) and estimated sleep latency. We conclude that the prevalence of DIS was fairly similar at these four European centers but that there was a variation in the prevalence of nightmares and nocturnal awakenings. The significant correlation between reported GER and subjective quality of sleep should be followed up in studies using objective measurements.

[Atopic allergy in an Icelandic urban population 20-44 years of age.]

This is a part of a second stage of EC Respiratory Health Survey and the aim of this study is to estimate the prevalence of atopic allergy among urban population of men and women aged 2CM4 years, living in the capital Reykjavik and suburbs. Altogether 800 individuals were invited of whom 570 participated (77%). All participants answered questionnaire and 540 individuals were skin prick tested by 12 allergens. 20.5% had positive skin tests, defined as at least one allergen positive by a weal reaction of 5=3 mm, 20.1% male and 20.9% female. The highest prevalence of allergy was in the agegroup 20-24 years. Results of single allergens: timothy grass 8.5%, cat 7.6%, dog 6.3%, D. pteronyssinus 6.1%, Lepidoglyphus destructor 3.2%, birch 3.0% and Cladosporium 1.1%. Other allergens reacted positive in less than 1% each; altogether 11.2% were positive to one or more animals and 10.6% to timothy and/or birch. RAST tests were done by five allergens. RAST results =50.35 ku/1 (RAST class 5=1) to timothy was 11.9%, to cat 7.5%, to D pteronyssinus 9.2%, to birch 5.9% and to cladosporium 6.5%. The only statistically significant risk factor for allergy was mothers history of allergy symptoms. Compared to already published data from other EC Respiratory Health Survey countries, the prevalence of atopic allergy appear to below in Iceland.

Epidemiological aspects of snoring and hypertension

Previous studies have reported a great difference in snoring prevalence in different populations. In a recent study on men and women 20-45 y old, living in Sweden (Uppsala, Gothenbourg), Iceland (Reykjavík) and Belgium (Antwerp), data concerning snoring, etc., were collected using the same questions and scales in all the countries. In all four areas the prevalence of snoring was the same: 5% of men and 2-3% of women reported snoring every night. In all areas snoring was positively correlated with age, male sex and body mass index. It was therefore assumed that the previous difference in snoring prevalence is probably an artifact of different methodologies. The connection between snoring and systemic hypertension has been much disputed during the last decade. The high prevalence of hypertension in the sleep apnoea syndrome has been explained by obesity/age/male gender/sleep apnoea and/or snoring. In one recent study snoring did not contribute independently to the prediction of hypertension, while other studies indicate that snoring is an independent risk factor for hypertension. After reviewing some of the epidemiological literature it was found that these studies are bound to identify almost entirely different subgroups of the population as snorers since the prevalence of snoring is rated on different types of frequency scales with words like 'never', 'often' or the number of nights per week. The questions used are also different. In general it can be stated that the smaller the proportion of the population identified as snorers the more often there is a statistically significant association with hypertension. The relationship between snoring and hypertension is considered to be unclear due to the different research methods used, and to the uncertain role played by confounding factors such as obesity. There is a need for population-based, prospective, studies with more uniform definitions of the term 'snoring' based on objective measurements of upper airway resistance during sleep, together with haemodynamic studies.

Continuous intrathoracic pressure monitoring with a new esophageal microchip catheter in sleep-related upper airway obstructions

A new small-diameter microchip catheter, especially developed for continuous intrathoracic pressure monitoring to assess the degree of respiratory obstruction and effort in patients with sleep-related upper airway obstructions, was investigated. The technical performance and clinical applicability of the catheter was tested in a simplified screening study comprising 122 sleep recordings in patients with varying complaints of snoring and daytime tiredness. In six obese snorers, sensitivity of the catheter to apneas, hypopneas, and nonapneic snoring was compared to the traditional assessment of respiratory events by conventional polysomnography. The catheter was found to be easy to handle and introduce, with technical qualities meeting the demands for overnight recordings of intrathoracic pressure variations. Patient tolerance was high (93%), and sensitivity to apneas and hypopneas was equivalent to that of traditional polysomnography. Periods with upper airway obstruction and increased respiratory effort on the borderline between asymptomatic obstructions and obstructions resulting in significant blood-gas changes could be detected primarily with intrathoracic pressure monitoring. Monitoring the intrathoracic pressure variations in the esophagus has been shown previously to reflect respiratory effort. Increased respiratory effort might be one of the explanations for the fragmented sleep patterns and sleep related daytime symptoms sometimes seen in patients without a pathologic respiratory index. In addition to being applicable for the detection of apneas and hypopneas, continuous nocturnal monitoring of the intrathoracic pressure variations also detects small increases in respiratory effort and thus may constitute a valuable tool for the understanding and diagnosis of upper airway resistance syndrome and obstructive sleep apnea syndrome.

Basic Nordic Sleep Questionnaire (BNSQ): a quantitated measure of subjective sleep complaints

Sleep-related breathing disturbances, especially obstructive sleep apnoea syndrome (OSAS), are commonly encountered. Epidemiological studies from different countries have shown that poor sleep and complaints about insufficient sleep or poor sleep are often related to poor health. Different studies are, however, difficult to compare with each other. One of the main reasons for this is the frequent methodological differences between questionnaires. There is a need for uniform methods: we need to know the prevalence and incidence of sleep disorders, judged using the same criteria, and also the severity of each problem, i.e. how often a problem or a symptom happens/occurs. In 1988 the Scandinavian Sleep Research Society formed a task group for developing a standardized questionnaire that could be used as a basis for questionnaires used in the Nordic countries. In this article we describe the Basic Nordic Sleep Questionnaire (BNSQ). The main change compared to many previous questionnaires is the five-point scale (scale from 1 to 5) stressing on how many nights/days per week something happens. The basic scale is: 1, 'never or less than once per month'; 2, 'less than once per week'; 3, 'on 1-2 nights per week'; 4, 'on 3-5 nights per week'; and 5, 'every night or almost every night'. For questions about specific rare events the first category may be divided into 'never' and 'less than once per month'. Habitually occurring events such as 'habitual snoring' are defined here as snoring every night or almost every night. The BNSQ has been used widely in a variety of studies performed in Nordic countries during the last years, and it has proven to be a valid tool.

Snoring, apneic episodes, and nocturnal hypoxemia among children 6 months to 6 years old. An epidemiologic study of lower limit of prevalence

STUDY OBJECTIVE

To identify a lower limit of the prevalence of sleep-related breathing disturbances among preschool children.

DESIGN

A cross-sectional epidemiologic study in two stages, first by questionnaires and second by whole-night investigation of children symptomatic of the sleep apnea syndrome.

SETTING

Gardabaer, a small town, 10 km south of Reykjavìk, Iceland.

PARTICIPANTS

All children in Gardabaer, 6 months to 6 years old (n = 555).

MEASUREMENTS

Symptom score estimated by questionnaire and respiratory events based on overnight oximetry, thermistors, and a static charge sensitive bed.

RESULTS

The response rate was 81.8%. Snoring was reported as often or very often among 14 (3.2%) and occasionally by 73 (16.7%). Apneic episodes were reported often or very often among seven (1.6%). Altogether 18 children were highly suspected of the sleep apnea syndrome because of habitual snoring or apneic episodes. The girls (n = 9) were older than the boys (mean age: 46 +/- 21 months vs 20 +/- 12 months, p < 0.001). Eventually 11 children came for a whole-night investigation and 8 of them showed more than three respiratory events per hour of sleep, associated with > or = 4% oxygen desaturation. The lower limit of the sleep apnea syndrome prevalence among these children was thus 2.9% (SE, 0.5%).

CONCLUSIONS

Among children, symptoms such as snoring and apneic episodes are reported relatively seldom, but a high proportion of the children with these symptoms have hypoxic respiratory events.