Prevalence of snoring and the risk of sleep apnea in hospital staff

Abstract

BACKGROUND: Untreated Obstructive sleep apnea syndrome (OSAS) as a common breathing sleep disorder results in impaired work performance. The economic burden of untreated OSAS accounts for billions of dollars per year.

OBJECTIVE: The aim of this study was to evaluate the prevalence of snoring and the risk of OSAS in healthcare system staff.

METHODS: This cross-sectional study was performed on 715 staff of Dr. Masih Daneshvari Hospital in 2012. The Berlin questionnaire was used to identify the prevalence of snoring and the risk of sleep apnea. Additional information, including demographic characteristics, night work, night sleep less than 4 hours, smoking, underlying disease, and quality of sleep were evaluated as well. The information was analyzed using SPSS 15.

RESULTS: 12.6% reported snoring. 6.9% and 93.1% were categorized into the high and low risk groups for OSAS respectively. There was an association between the risk of OSAS and age group (P-value = 0.007), gender (P-value = 0.028), marital status (P-value = 0.008), educational level (P-value = 0.035), chronic disease (P-value = 0.008), night sleep less than 4 hours (P-value = 0.001), difficulty in staying asleep (P-value = 0.000) and waking up too early (P-value = 0.006). Even logistic regression analysis demonstrated the relationship between the risk of OSAS and night sleep less than 4 hours (P-value = 0.019) and difficulty in staying asleep (P-value = 0.009).

CONCLUSIONS: The results showed that the risk of OSAS is significant in healthcare system staff. Hope to provide a special screening program for OSAS in a regular occupational examination.

Keywords

Obstructive sleep apnea syndrome healthcare center worker Berlin questionnaire

1 Introduction

The risk of obstructive sleep apnea syndrome in Iran has been reported to be low compared to Western countries in some studies, but other studies have shown that this risk in Iran is significant [1, 2]. Sleep apnea is one of the most common sleep breathing disorders that cause sleepiness during the day [3]. Daytime sleepiness is very important in healthcare system staff as they are vulnerable to sleepiness due to night shift work. Sleep deprivation is not only caused by night shift work, but also occurs as a result of sleep disorders including sleep apnea.

It is crucial to determine the prevalence of sleep apnea as sleep apnea can affect health of hospital staff and make complications such as hypertension [4]. In total, sleep deprivation reduces health-related quality of life [5]. OSAS has received special attention in some professions such as drivers and there have been reports regarding daytime sleepiness and while driving [6]. In healthcare system staff, medical errors occur due to sleep deprivation. Several studies have indicated night shift and sleep deprivation as important causes of medical errors such as drug administration errors, incorrect operation of medical equipment, needle stick injuries, surgical errors and patient falls [7, 8].

Polysomnography is required to determine the prevalence of sleep apnea as one of the sleep disorders. Polysomnography is an overnight test to evaluate sleep disorders and includes monitoring of the patient’s airflow through the nose and mouth, blood pressure, electrocardiographic activity, blood oxygen level, brain wave pattern, eye movement and the movement of respiratory muscle and limbs. However, the Berlin questionnaire is also used to assess symptoms and the risk of sleep apnea in clinical and community-based samples [9]. This study is one of the few studies to investigate the risk and symptoms of obstructive sleep apnea in healthcare system employees.

Studies have indicated that symptoms of obstructive sleep apnea could be important predictors of absenteeism and permanent disability [10]. Several studies have been conducted on the risk of sleep apnea in some jobs, but a comprehensive study to identify the risk of sleep apnea in healthcare system employees has not been done. According to previous research, socioeconomic status and occupation have little impact on the risk of obstructive sleep apnea. However, some occupational groups have shown increased emergence of the risk of obstructive sleep apnea [11]. Untreated obstructive sleep apnea syndrome increases healthcare utilization and results in impaired performance at work. The economic burden of untreated obstructive sleep apnea syndrome accounts for billions of dollars per year [12]. In the case of staff members of healthcare systems, this is even more important due to the nature and importance of their job. Healthcare system staff are required to be alert and focused due to the nature of the job they do. However, alertness and focus, as the two major characteristics required for healthcare system staff, are sometimes affected by shift work. If sleep disorders, such as obstructive sleep apnea syndrome, affect awareness and focus in this occupational group, the probability of reduced performance at work may increase.

The objective of this study was to investigate the prevalence of snoring and the risk of sleep apnea in healthcare system staff.

2 Methodology

This cross-sectional study was conducted by the Research Institute of Tuberculosis and Lung Diseases, Dr. Masih Daneshvari Hospital in 2012. The study population included all the staff of Dr. Masih Daneshvari Hospital who accepted to participate in the study. The hospital staff responded to the Berlin questionnaire plus additional data. Staff responses to the translation of the Berlin questionnaire and additional data including demographic information, smoking habit, underlying disease, night shift work, and night sleep less than 4 hours and some questions about the quality of sleep were studied. It should be noted that the Berlin questionnaire was used after it underwent a process of translation and back translation followed by being compared to the original copy by experts who were fluent in both English and Persian.

2.1 Instrument

The instrument was Berlin questionnaire plus additional data including age, sex, marriage status, smoking status, education, income, night shift, chronic disease, history of night sleep less than 4 hours, trouble in beginning of sleep or sleep continuing and early waking up. The Berlin questionnaire consists of three parts including 10 questions. The questions and available answers to the questions of the instrument are shown in Table 2. Different parts of the Berlin questionnaire include:

Part I: Presence or absence of snoring and its characteristics, breathing interruption during sleep noticed by family

Part II: fatigue after sleep, fatigue and sleepiness during the day and falling asleep while driving

Part III: history of hypertension and BMI over 30

The participants that scored positive in two out of the three parts of the defined criteria mentioned in the questionnaire were considered to be high-risk in terms of developing obstructive sleep apnea; otherwise they were considered low-risk [9]. The questionnaire was evaluated in terms of validity and reliability by many experts in the field. After completion of the questionnaire by 30 people (the pilot project) a Cronbach’s alpha 0.87 was obtained.

2.2 Data collection

When the staffs were referred for annual periodic health examinations, the questionnaire was anonymously completed by those who agreed to participate in the research. The respondents were reminded about the importance of being accurate in responding to the questions. The questionnaire was completed by an expert if the participant was not able to complete the questionnaire by themselves.

2.3 Data analysis

The data were analyzed statistically using SPSS 15 and the risk of sleep apnea as well as its association with sociodemographic factors and other probable factors were studied. Level of significance was set at 0.05. The study was approved by the ethics committee of National Research Institute of Tuberculosis and Lung Diseases, Dr. Masih Daneshvari Hospital. According to the Declaration of Helsinki, ethical considerations such as voluntary participation, participant informed consent, and confidentiality was respected.

3 Results

3.1 Participant demographics

Out of 800 questionnaires, 715 were completed by the hospital staff and entered the study for a response rate of 89.4%. Demographic information of participants is shown in Table 1. Average age of the participants was 33.51 years old (SD = 7.65). Four hundred and six (56.8%) had the experience of night shift, whereas 309 (43.2%) did not report night work shift. One hundred ninety one (26.7%) reported a history of chronic disease. However, 522 (73%) did not report a history of chronic disease and 2 (0.3%) did not answer the question.

3.2 Sleep apnea

Mean BMI was 25.17 kg/m2 (SD = 8.85). Of the sample, 90 (12.6%) reported a history of snoring; response of the employees to other parts of the Berlin questionnaire is demonstrated in Table 2. In terms of the risk of sleep apnea, 49 (6.9%) and 666 (93.1%) were categorized into the high-risk and low-risk groups, respectively.

Table 3 shows the relationship between the risk of sleep apnea and demographic factors and other probable factors. The risk of sleep apnea in the age group over 35 was shown to be higher, as compared to that in those younger than 35 years old (OR = 2.190, CI = 1.220–3.933, P-value = 0.007). Similarly, it was reported to be higher in men than in women (OR = 1.914, CI = 1.063–3.449, P-value = 0.028). The risk of sleep apnea was also shown to be higher in married people, as compared to single ones (OR = 2.545, CI = 1.249–5.187, P-value = 0.008). Likewise, it was reported to be higher in those who have Undergraduate degree, as compared to those having done postgraduate studies (OR = 1.861, CI = 1.035–3.345, P-value = 0.035).

The respondents having a history of chronic disease developed a higher risk of sleep apnea in comparison with those with no chronic disease (OR = 2.179, CI = 1.206–3.940, P-value = 0.008). The individuals with a history of less than 4 hours night sleep reported to be at a higher risk of developing sleep apnea, as compared to those who did not have the experience of sleep less than 4 hours (OR = 2.803, CI = 1.460–5.380, P-value = 0.001). The risk of sleep apnea was shown to be higher in people who had trouble staying asleep in comparison with those without this problem (OR = 3.578, CI = 1.968–6.506, P-value = 0.000). Also in those who woke up early in the morning, the risk of sleep apnea was noted to be higher in comparison with those without this problem (OR = 2.278, CI = 1.256–4.131, P-value = 0.006). Association of sleep apnea risk with smoking, night shift, monthly income and difficulty in sleeping was not statistically significant (Table 2).

Logistic regression analysis was used to assess the association between the risk of sleep apnea and demographic and other probable factors (Table 4). Based on this analysis, even after adjusting for confounding factors, the association between the risk of sleep apnea and night sleep less than 4 hours (OR = 2.273, CI = 1.142–4.523, P-value = 0.019) and difficulty in staying asleep (OR = 2.515, CI = 1.258–5.031, P-value = 0.009) showed to be statistically significant.

4 Discussion

The results of the current study indicated that 6.9% of the sample of healthcare workers were considered to be high-risk for developing sleep apnea and risk of sleep apnea was associated with age, sex, marriage status, educational level, chronic disease, low night sleep and some sleep problems.

Using the Berlin questionnaire, Amra et al. and Khazaei et al., reported the risk of sleep apnea to be 4.98% and 27.3%, respectively [1, 2]. The current study included a particular occupational group. However, the studies conducted by Amra et al. and Khazaei et al. were carried out on Iranian general population.

Using the Berlin questionnaire, 24% of nurses who had 12 hours of night shift were considered to be at high-risk in terms of developing sleep apnea [9]. However, our study was conducted on all the staff of the hospital and not only on nurses. Moreover, the current study included a bigger sample size. In addition, mean age in the study by Geiger-Brown was 40 years old, whereas in the current study, mean age was 33.51 years old. Studies have shown that the risk of sleep apnea increases as the age increases [13, 14]. In our study, the risk of sleep apnea was directly associated with the age group above 35 too. In present study, the history of snoring was reported to be 12.6%, whereas in the study by Geiger-Brown, it was reported to be 42.8% [9]. These differences could be related to lower mean age in our sample.

In the recent study, a direct statistically significant relationship was observed between the risk of sleep apnea and being male. This result is in accordance with those obtained in the previous studies [13 –16].

According to the results of the study carried out on adults in Turkey, using the Berlin questionnaire, the risk of sleep apnea in married individuals was higher than that in single ones [17]. In this study, the risk of sleep apnea was higher in married respondents, as compared to that in unmarried individuals. Higher risk of sleep apnea in married participants can be attributed to two factors: Firstly, married participants are more likely to be in a higher age group; secondly, as a married person, the chances of getting noticed for snoring and breathing stoppage during sleep are higher. Therefore further reports are available by married individuals.

Studies have reported smoking-associated sleep apnea caused by inflammation of the airways due to smoking [13 , 17]. However, in the current study, although the risk of developing obstructive sleep apnea was higher among smokers (10.3%) than that among non-smokers (6.7%), this association was not statistically significant. Perhaps this issue could be attributable to the tobacco-free policy at the hospital that could have caused some employees to deny smoking; as a result, some smokers fell into the category of non-smokers.

The risk of sleep apnea in the participants enjoying higher level of education (postgraduates) was lower than that in those having BSc. This indirect relationship between the risk of sleep apnea and educational level was demonstrated in the study conducted by Amra as well [1]. This may occur due to higher BMI in people with lower educational levels [18, 19] and that according to the Berlin questionnaire, high BMI is one of the factors that cause an individual to fall into the high-risk group.

In addition, several studies have shown the relationship between some chronic diseases such as COPD, chronic kidney disease and atherosclerosis and obstructive sleep apnea [20 –22]. In this study, the association between the risk of sleep apnea and chronic diseases was shown to be statistically significant. There are several hypotheses about the causes of the association between chronic diseases and sleep apnea that have not been proven and are under investigation. In people aged 55 to 84, it has been shown that obesity, arthritis, diabetes, lung disease, heart stroke and osteoporosis are associated with interrupted respiration and snoring [23].

In the recent study, the risk of sleep apnea and night shift did not show a statistically significant relationship. In the study carried out by Soylu conducted on nurses and doctors (residents of a university hospital), as well as the study carried out by Yazdi et al. on textile factory employees, no relationship was observed. [24, 25].

Demir and colleagues indicated the higher risk of sleep apnea among low-income individuals [17]. This finding was confirmed by the present study. But as shown in some studies in Iranian society, there is a direct relationship between socio-economic status and the risk of obesity [26]. Increased risk of sleep apnea in low-income individuals should be further investigated.

The association between inadequate night sleep and BMI and high blood pressure has been shown in previous studies [27, 28]. According to the Berlin questionnaire, high BMI and blood pressure are significant factors to cause an individual to fall into the high-risk group. Hence, night sleep less than 4 hours, difficulty staying asleep, and waking up early that each results in getting insufficient sleep at night are the factors that can justify the higher risk of sleep apnea in this study.

On the other hand, obstructive sleep apnea can cause the person to wake up frequently during the night and may result in insomnia [29, 30]. This relationship is demonstrated in the recent study. Both Insufficient night sleep and sleep apnea impair daytime performance [31, 32]. The latter is very important for healthcare system staff. The associations of sleep apnea risk with night sleep less than 4 hours and difficulty staying asleep even after adjusting for other factors showed to be still significant.

In general, studies have shown that obstructive sleep apnea increases cardiometabolic morbidity and mortality [14, 33], moderate to severe sleep apnea is related to the increased risk of mortality in general [34] and economic loss caused by obstructive sleep apnea is significant [12]. Overall, the direct and indirect economic cost of sleep disorders is high [35]. Sleep disorders such as obstructive sleep apnea especially in some specific occupational groups such as healthcare system require special attention.

Although this study was done in a particular occupational group, the sample size was acceptable. Moreover, the idea of the current study, assessment of the risk of sleep apnea in a particular occupational group (hospital staff) was also novel.

Inability to accurately determine whether or not the participants suffer from sleep apnea by using the Berlin questionnaire was a major limitation of the study. Due to the high cost of using accurate methods such as polysomnography for this big sample size, we could only assess the risk of sleep apnea. In order to determine the exact prevalence of obstructive sleep apnea in the staff of healthcare systems, it is hoped that in the future the possibility of using accurate methods such as polysomnography will be provided.

5 Conclusion

The results of the study indicated that the risk of sleep apnea is significant among the staff of healthcare systems and that sleep apnea is a major issue with regard to the health of the staff. Also it was shown that the risk of sleep apnea is associated with certain factors. It is hoped that in the future, a special screening programme will be provided for detection of symptoms and risk factors of sleep apnea. Screening tests are recommended to be conducted in a regular professional examination basis and the appropriate treatment is also suggested.

Conflict of interest

None to report.

Footnotes

Acknowledgments

The authors would like to thank NRITLD for supporting this project and the staff of Dr. Masih Daneshvari Hospital for the cooperation in collecting data.

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