in Sivas, Turkey
Levent ÖZDEMİR1, İbrahim AKKURT2, Haldun SÜMER1, Selma ÇETİNKAYA1, Uğur GÖNLÜGÜR2, Sefa Levent ÖZŞAHİN2, Naim NUR1, Ömer DOĞAN2
1Cumhuriyet Üniversitesi Tıp Fakültesi, Halk Sağlığı Anabilim Dalı,
2Cumhuriyet Üniversitesi Tıp Fakültesi, Göğüs Hastalıkları Anabilim Dalı, Sivas.
ÖZET
Sivas’ta uyku ile ilişkili bozuklukların sıklığı
Türkiye’de erişkinlerde uyku ile ilişkili bozuklukların sıklığı bilinmemektedir. Çalışmamızın ana amacı Sivas’ta uyku ile ilişkili bozuklukların sıklığını ölçmekti. Çalışma, Türkiye’de İç Anadolu’nun bir ili olan Sivas’ta yaşayan 20-107 yaş arası erişkinlerde, 2701 (%50.6)’i kadın 2638 (%49.4)’i erkek toplam 5339 kişide uygulanmıştır. Uykusuzluk, horlama hastalığı, obstrüktif uyku apnesi, gündüz uykuya meyil sıklığı sırasıyla %40.3, %37.0, %6.4, %24.0 idi. Narkolepsi ve nokturnal myoklonus sıklığı sırasıyla %30.6, %40.1 idi. Altmış yaş üzeri grupla diğer yaş grupları arasında istatistiksel olarak anlam- lı farklılık tespit edildi. Uyku ile ilgili bozukluk sıklığı açısından hem sigara içenler ve içmeyenler hem de erkek ve kadın- lar arasında farklılık bulmadık (p> 0.05). Bununla beraber, hipertansiflerde uyku apnesi sıklığı hipertansif olmayanlara gö- re dokuz kat, şişmanlarda da 12 kat fazla idi. Çalışmamız ülkemizde uykuda solunum bozuklukları sıklığının diğer ülke- ler kadar, belki de daha yaygın olduğunu göstermektedir.
Anahtar Kelimeler: Sıklık, uyku bozukluğu, Türkiye.
SUMMARY
The prevalence of sleep related disorders in Sivas, Turkey
Ozdemir L, Akkurt I, Sumer H, Cetinkaya S, Gonlugur U, Ozsahin SL, Nur N, Dogan O Department of Public Health, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey.
The prevalence of sleep-related disorders (SRD) in adults in Turkey is unknown. The main objective of our study was to as- sess the prevalence of SRD in Sivas, Turkey. Adults living in Sivas, a city of Turkey from the central region of Anatolia at 20-107 years of age, in both genders, of the 5339 persons, who attended the survey 2638 (49.4%) were male and 2701 (50.6%) were female. The prevalence of insomnia, habitual snoring, obstructive sleep apnea (OSA) and day time hyper somnolence was 40.3%, 37.0%, 6.4%, 24.0% respectively. The prevalence rates of narcolepsy and nocturnal myoclonus was 30.6%, 40.1% respectively. There was a statistical significance between the persons of above 60 years old and another age groups (p< 0.05). But we did not find any significant difference between smokers and non-smokers, also between males
Yazışma Adresi (Address for Correspondence):
Dr. Levent ÖZDEMİR, Cumhuriyet Üniversitesi Tıp Fakültesi, Halk Sağlığı Anabilim Dalı, SİVAS - TURKEY e-mail: lozdemir@cumhuriyet.edu.tr
Sleep related disorder (SRD) is an extremely common medical disorder that is associated with considerable morbidity. Sleep apnea has been recognized as an important clinical condi- tion only for the past 30 years (1). Various stu- dies have reported community prevalence of ha- bitual snoring in adults to be about 11.0-15.0%.
About 30-50% of adult habitual snorers are esti- mated to have sleep apnea/hypopnoea, which is estimated to occur in 2.0-4.0% of the general population (2-4). Habitual snoring has been shown to be independently associated with the development of stroke, hypertension, and myo- cardial infarction in the general population (5-7).
Under diagnosed SRD represents a major public health burden (8). Excessive sleepiness has be- en increasingly recognized as an important pub- lic health problem, estimated to affect at least 12 to 20% of the general adult population and contributing to both motor-vehicle and work-re- lated accidents, impaired social functioning, and reduced quality of life (9,10). Although cases of SRD have been documented in most of countri- es, in our knowledge, its prevalence is unknown in Turkey. So, in this study, we attempted to de- termine the prevalence of symptoms related to SRD in the adult population in Sivas, Turkey by a questionnaire survey.
MATERIALS and METHODS
The study population included the inhabitants of Sivas, at or above 20 years of age, selected ran- domly and gave consent to the study. The study region was Sivas, far from Ankara nearly 450 ki- lometres, in the north-eastern region of central Anatolia, with a population of 272.846. The po- pulation of 20 years or above of age was 182.926 (1997 national census, and yearly he- alth statistic findings). When expected prevalen- ce of SRD was thought to be 10.0%, statistically expected population to reach was calculated
from known formulation as 5846 persons who consist of a simple random sample of clusters of individuals. The study region was Sivas, has a dry and cold climate, and the air pollution level is much higher especially at winter like other Turkish cities. This was a cross-sectional study including a questionnaire survey. Turkish-langu- age version of the modified Sleep and Health Questionnaire is a modified version of the Speci- alised Centres of Research Sleep Questionnaire, which has been shown previously to be a valid means of characterising symptom distribution in population surveys of sleep apnea. The questi- onnaire contains 47 questions grouped into five factors (demographic characteristics/smoking habits, insomnia, sleep apnea, narcolepsy, and nocturnal myoclonus) that have been shown to be useful in predicting the occurrence of SRD (11-14). Questionnaire forms were given to the subjects by face to face interviewing method.
From totally 5846 forms, 5339 (91.3%) were answered while the others were rejected or not found. The answers to the related SRD questions utilized either “yes” or “no”. These questions are shown in the Results’ tables. Findings of the study are presented as the mean ± SD for the numbers and the prevalence rate for the frequ- encies. In the statistical comparisons t-test, Fis- her exact Chi-Square test and Mantel-Haenszel for estimated common Odds Ratio were used.
Statistical significance was assumed for a value of p< 0.05.
RESULTS
From totally 5846 persons, 5339 (91.3%) were included into the study. Of the 5339 adults, who attended the survey, 2638 (49.4%) were male and 2701 (50.6%) were female. Table 1 shows the age, gender, and smoking behaviour of the study population. The age range of the survey population was 20 to 107 years with the mean and females about SRD prevalence (p> 0.05). However, sleep apnea prevalence was about 9 times higher in the persons suffering from hypertension than without hypertension. Also sleep apnea prevalence was 12 times higher in the persons suffering from overweight. This study has shown that sleep-disordered breathing (SDB) prevalence in Turkey is as high as in other countries and may be more common.
Key Words: Prevalence, sleep disorder, Turkey.
age of 38.4 years (SD= 12.6 years). Almost half of the study population were at or below 40 ye- ars of age. There were 1297 (49.2%) men and 374 (13.8%) women who admitted that they ha- ve smoked. The prevalence of ever smoking among the men were statistically higher than women (p< 0.001). The questions and answers of the cases related to insomnia are shown on Table 2. The prevalence of insomnia was 40.3%
(2152). The prevalence rates of habitual sno- ring, obstructive sleep apnea (OSA) and day ti- me hyper somnolence were 37.0% (1977), 6.4%
(342) and 24.0% (1280) respectively. When we take into account at least 3 “yes” answers to these questions related to sleep apnea, the pre- valence was found 43.7% (2331) (Table 3). The prevalence of narcolepsy was 30.6% (1633) (Table 4). The questions and answers of the ca- ses related to nocturnal myoclonus have been shown on Table 5. The prevalence rate of noc- turnal myoclonus was 40.1% (2139). Table 6 shows the prevalence of SRD according to age groups. There was a statistical significance bet-
ween the persons of above 60 years old and another age groups (p< 0.05). But we did not find any significant difference between smokers and non-smokers, also between males and fe- males about SRD prevalence rate (p> 0.05). Ho- wever, sleep apnea prevalence was about 9 ti- mes higher in the persons suffering from hyper- tension than the subjects without hypertension.
Also sleep apnea prevalence was 12 times hig- her in the persons suffering from overweight (Table 7).
DISCUSSION
Obstructive sleep apnea syndrome (OSAS) is the most common organic disorder of excessive daytime somnolence. In cross-sectional studies the minimum prevalence of OSAS among adult men is about 1%. Prevalence is the highest among men aged 40-65 years. The highest figu- res for this age group indicate that their preva- lence of clinically significant OSAS may be 8.5%
or higher. The most significant risk factor for OSAS is obesity, especially upper body obesity.
Table 1. Gender, age and smoking behaviour of the study population.
Men Women Total
n (%) 2638 (49.4) 2701 (50.6) 5339 (100.0)
Mean age (SD) 40.0 (12.0)* 36.9 (13.1)* 38.4 (12.6)
Ever smoked n (%) 1297 (49.2)* 374 (13.8)* 1671 (31.3)
* p< 0.001.
Table 2. The questions and answers of the cases related to insomnia (n= 5339).
Yes
Questions n %
Do you have difficulty to sleep? 1494 28.0
Do you feel like you can not sleep due to your constant thoughts? 1634 30.6 Are you afraid that something bad will happen when you are sleeping? 412 7.7
Do you occupy yourself with worriment for everything? 1979 37.1
Do you wake up feeling that you did not get enough sleep? 2056 38.5
Is it taking you at least half an hour to fall asleep? 2751 51.5
Are you upset and unhappy? 840 15.7
Do you have problem of waking in the night and not being able to sleep again? 1422 26.6
INSOMNIA (at least 3 “yes” answers to these questions) 2152 40.3
Table 3. The questions and answers of the cases related to sleep apnea (n= 5339).
Yes
Questions n %
Did anybody tell you that you are snoring whenever you sleep? 1977 37.0
Did anybody tell you that you stop breathing when you sleep? 342 6.4
Do you have high blood pressure? 733 13.7
Did anybody tell you that there are changes in your attitude? 540 10.1
Did you put on too much weight lately? 1524 28.5
Do you sweat a lot during night? 1224 22.9
Does your heart beat irregularly during night? 608 11.4
Do you wake up with headache in the morning? 1256 23.5
Do you have difficult sleeping when you have flu? 2476 46.4
Do you wake up in the night with shortness of breath? 568 10.6
Are you overweight? 683 12.8
Do you think there is a decrease in your sexual performance? 638 11.9
Do you feel sleepy during the day although you get enough sleep during the night? 1280 24.0
SLEEP APNEA (at least 3 “yes” answers to these questions) 2331 43.7
Table 4. Narcolepsy related questions and answers (n= 5339).
Yes
Questions n %
Are you having difficulty to concentrate? 1218 22.8
Do you feel numb when you are nervous? 2177 40.8
Do you feel sleepy when you drive? 108 2.0
Do you feel dazed sometimes? 1789 33.5
Do you see any image that seems alive when you were falling sleep or waking up? 550 10.3
Do you feel sleepy when you work? 459 8.6
Do you hear or see anything unreal when you fall asleep? 529 9.9
Do you feel you need to finish all day work in an hour and get frustrated? 1365 25.6
Do you fall asleep when you laugh or cry? 223 4.2
Do you think that you are unsuccessful in your work since you are sleepy most of the time? 251 4.7
Do you see any nightmares right after you fall asleep? 502 9.4
Do you feel sleepy all day long? 414 7.8
Do you feel it is difficult to stay awake and you can sleep under any circumstance? 489 9.2 Do you feel your actions/motions are blocked when you fall asleep or wake up? 563 10.5
NARCOLEPSY (at least 3 “yes” answers to these questions) 1633 30.6
Table 5. The questions and answers of cases related to nocturnal myoclonus (n= 5339).
Yes
Questions n %
Do you feel that your leg muscles are strecthed even when you are rested? 1462 27.4
Do you feel shivering in your body? 959 18.0
Have you ever been told that you are kicking while you are sleeping? 504 9.4
Do you have any pain or feel numb in your legs? 2055 38.5
Do you suffer from leg pain during night? 1456 27.3
Do you need to move your legs while sleeping at night? 1151 21.6
Do you wake up with muscle pain? 1045 19.6
Do you feel sleepy during the day even when you get enough sleep? 899 16.8 NOCTURNAL MYOCLONUS (at least 2 “yes” answers to these questions) 2139 40.1
Table 6. Prevalence of SRD according to age groups.
Age Sleep Nocturnal
groups Insomnia apnea Narcolepsy myoclonus Total
(years) n % n % n % n % n %
20-29 603 38.2 583 37.0 505 32.0 570 36.1 1577 29.5
30-39 611 40.3 624 41.2 490 32.3 635 41.9 1516 28.4
40-49 460 36.7 553 44.1 307 24.5 467 37.2 1254 23.5
50-59 284 43.5 336 51.5 188 28.8 274 42.0 653 12.3
60+ 194 57.2* 235 69.3* 143 42.2* 193 56.9* 339 6.3
Total 2152 40.3 2331 43.7 1633 30.6 2139 40.1 5339 100.0
p< 0.05.
Table 7. The risk factors related to sleep-disordered breathing (SDB).
With healthy Without healthy p: Overweight Not overweight p:
persons persons OR*: persons persons OR:
(n= 733) (n= 4606) (95% CI)** (n= 683) (n= 4656) (95% CI)
Insomnia n (%)
464 (63.0) 1688 (36.6) 0.001 381 (55.8) 1771 (38.0) 0.001
2.9 2.1
(2.5-3.5) (1.7-2.4)
Sleep apnea n (%)
622 (84.6) 1711 (37.1) 0.001 599 (87.7) 1732 (37.2) 0.001
9.3 12.0
(7.5-11.4) (9.5-15.2)
Narcolepsy n (%)
363 (49.5) 1270 (27.6) 0.001 314 (46.0) 1319 (28.3) 0.001
2.6 2.2
(2.2-3.0) (1.8-2.5)
Nocturnal myoclonus
n (%) 448 (61.1) 1691 (36.7) 0.001 402 (58.9) 1737 (37.3) 0.001
2.7 2.4
(2.3-3.2) (2.0-2.8)
* OR: Odds ratio.
** 95% CI: Confidence Interval 95%.
Other risk factors for snoring, and for OSAS, are male gender, age between 40 and 65 years, ci- garette smoking, use of alcohol, and poor physi- cal fitness (15). Ulfberg et al. reported that sle- ep related complaints were more frequent among the restless leg syndrome (RLS) suffe- rers (16). Although questionnaires have been developed to assess symptoms of obstructive sleep apnea (OSA), their overall reliability and utility have not been established. Kump et al.
had evaluated the ability of a questionnaire to identify increased apnea activity in 465 partici- pants in an epidemiological study of OSA and shown that questionnaire data provide a valid means of characterizing symptom distributions in population surveys of OSA (11). This study confirms that SRD may be very prevalent in the general population. The present results are strengthened by the very high response rate of 91.3%. Our findings of habitual snoring in 37.0%
of the population, breathing pause in 6.4%, and day time hyper somnolence in 24.0% are nearly consistent with those found by others and indi- cate that symptoms of SRD are common in the general population (8,17-19). The sleep history is essential to recognize clinically important sle- ep disorders (20). Recent epidemiological ob- servations suggest that approximately 90.0% of persons with clinically significant OSA have not been recognized (21). If potentially treatable sle- ep problems are to be recognized and managed, then the barriers to optimal health-care provider behaviours must be defined and addressed.
Further prospective study may require not only a large cohort but also a refined prompt that more emphatically promotes a response by the caregiver. The low frequency of action may ref- lect physicians’ suboptimal knowledge and atti- tudes about sleep disorders and suggest an im- portant educational need (20). The American Sleep Disorders Association Taskforce 2000 Survey has confirmed that physicians receive, on average, only 2.1 h of education in the area of sleep disorders after 4 years of medical edu- cation (22). In our knowledge, in Turkey, physi- cians receive, on average, only one hour of edu- cation in the area of sleep disorders after 6 ye- ars of medical education. Namen and colleagu-
es believe that chest clinicians active in the eva- luation and management of patients with SRD must have a major role in this educational effort.
We have been set up polysomniagraphy (PSG) unit in our chest clinic, but firstly we established this questionnaire survey to detect general po- pulation in our region by symptoms, demograp- hic characteristics, and risk factors. Hui et al.
analyzed the potential factors that may predict snoring and SRD. They reported that male gen- der is significantly related with snoring (12). Du- ran et al. reported that the prevalence of habitu- al snoring is 35.0%, and they concluded that there is a link between hypertension and obst- ructive sleep apnea-hypopnoea (OSAH) in the general population (8). Carmelli et al. reported that, the prevalence of self-reported snoring is 26.0%, excessive daytime sleepiness (EDS) is 18.0%. By using structural equation modelling, they estimated that genetic factors accounted for 64.0% of the variance in obesity, 40.0% of the variance in daytime sleepiness, and 23.0% of the variability in self-reports of snoring. And they concluded that self-reported symptoms of sno- ring and daytime sleepiness in older men have a genetic basis (23). Ng et al. reported that mar- ked ethnic differences in snoring and sleep bre- athing-related disorders were observed in Chi- nese, Malays and Indians in Singapore, which were only partly explained by known factors of sex, age and body habitus (24). Habitual sno- ring was reported as 23.0% by Ip et al. and was associated with EDS; hypertension, witnessed abnormal breathing pattern, body mass index (BMI), and leg movements during sleep (25). In our study, the prevalence of habitual snoring was 37.0% (1977), and OSA was 6.4% (342), day time hyper somnolence was 24.0% (1280).
When we take into account at least 3 “yes” ans- wers to these questions related to sleep apnea, the prevalence was found as 43.7% (2331) (Table 3). The prevalence of narcolepsy, and nocturnal myoclonus was 30.6%, 40.1% respec- tively (Table 4, 5). Although OSA is associated with chronic hypertension, not all subjects with SRD are hypertensive (26-28). A form of SRD is upper airway resistance syndrome (UARS). Gu- illeminault et al. concluded that approximately
one fifth of subjects with UARS have low blood pressure and complain of orthostatic intolerance (29). In our study, sleep apnea prevalence was about 9 times higher in the persons suffering from hypertension than people without hyper- tension. Klink et al. found that among subjects with no respiratory symptoms, 28.0% reported insomnia (difficulty initiating or maintaining sle- ep) and 9.0% reported daytime sleepiness.
Among subjects with respiratory symptoms the rates were 52.8% and 22.8%, respectively (30).
In our questionnaire survey, the prevalence of insomnia was 40.3% (2152). Schmitt et al. were demonstrated the variety of sleep disorders oc- curring in a working population in Switzerland using a questionnaire. They found that the pre- valence rates of OSA, RLS, disorders of initiating and maintaining sleep, and narcolepsy were 6.0%, 4.0%, 19.0%, and 0.5% respectively (31).
Köktürk et al have reported that the frequency of OSA was determined in 15 (%27.3) of 55 pa- tients with habitual snoring (32). Ganguli et al.
reported the prevalence and persistence of sle- ep complaints in a rural older community samp- le. They found that the prevalence of snoring was 40.0%, and snoring was significantly more common among men (33). Ulfberg et al. had re- ported that the specificity of the questions abo- ut snoring as 83.0% and the sensitivity as 42.0%.
The risk ratios for reporting EDS at work were 4- fold for snorers in the general population, 20- fold for snoring patients, and 40-fold for patients with OSA as compared with no snoring men in the general population (34). Van Kralingen et al.
investigated sleep-related complaints and frequ- ency of SRD in a group of obese persons as part of a preoperative workup for weight reduction surgery and found that the prevalence of SRD in obese patients was 35.0% (35). In our study, sle- ep apnea prevalence was 12 times higher in the persons suffering from overweight than others (Table 7). Tachibana et al. examined the preva- lence of insomnia among Japanese male indust- rial workers and found that insomnia within the month preceding the survey was present in 27.7% of the workers (36). Recently, Krakow et al. assessed the prevalence of insomnia symp- toms in patients with objectively diagnosed as
sleep-disordered breathing (SDB) and conclu- ded that problematic insomnia symptoms were reported by 50.0% of a representative sample of patients with objectively diagnosed as SRD (37).
In our study, the prevalence of insomnia was fo- und as 40.3%. This study has shown that SDB prevalence in Turkey is as high as in other co- untries and may be more common. In fact, PSG is the gold-standard test for the diagnosis of SRD. However, our results have shown that in large populations questionnaires can also give some knowledge about SRD. By questionnaire assessment, SRD prevalence is high among adult people in Sivas, Turkey. We believe that further studies are required to determine the morbidity, mortality, and economic loss associ- ated with SRD in general population, especially in risk groups.
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