A total population of 304 patients (223 male and 81 female) with mean ages of 47.72 ± 12.68 in males and 49.70±12.15 in females was studied. Mean BMI was 30.26 ± 5.16 in males and 30.88±6.17 in females (Table 1). Mean age, sex and BMI did not differ among the four groups Total sleep duration was 380.16 ± 67.37 in males and 397,28 ± 58.0 in females (p=0.0501). We found that one season did not differ from the others, although patient AHIs were lowest in the spring and highest in the winter (Table 2, Figure 1). AHIs were highest in male patients with sleep apnea than female patients with sleep apnea (Figure 2).

Table 1


Table 2

Figure 1


Figure 2

In the present study, we have shown that patients with OSAS are not affected by the seasons. Although not statistically significant, we found that AHIs were lowest in the spring and highest in the winter. This runs contrary to some evidence in the literature indicating that patients with OSAS are affected by the seasons [10-12], although other sources have shown that patients with OSAS are not affected by the seasons. For instance, Dempsey demonstrated that airway infections and weather could have an effect on sleep apnea, but that the changes across the seasons had little effect on AHI values [13], while Cassol reported that more sleep disorder breathing events occurred in winter than in other seasons. They observed that people stopped breathing more than 30 times an hour in the colder months [14]. However, these differences may be associated with geographic location. The fact that many of these researchers are from Brazil and the USA could have affected their results. Our studies were conducted in Mu?la, but the same study may yield different results in another province.

Although inflammation and oxidative stress are important in the pathophysiology of OSAS, the relationship between inflammation remains poorly understood. Many factors affect the airway of a person with obstructive sleep apnea syndrome. For example, atmosphere and sun cycles can play a significant role in sleep quality [15]. Changes in seasons also affect the issue in different ways. Additionally, Kalra et al. found a high prevalence of snoring in young women with atopy and a significant association with asthma [11]. Similar studies have also shown that asthma is a frequent comorbidity in patients with OSAS (12). Similarly, Kalpaklioglu et al. reported that allergic rhinitis is a risk factor for a high apnea-hypopnea index, and after rhinitis treatment, a patient's AHI and Epworth Sleepiness Scale (ESS) scores will be reduced. They observed the most significant difference in a group treated with nasal steroid + antihistamine compared to the control group [16].
Several types of patients were included in this study, although ensuring similarity of age, sex and BMI may be considered one of its weaknesses. Here, using the same patients' PSG evaluation in different seasons would have been better. However, this was not attempted, as it was not covered by the study approval. In addition, patients who do not suffer from asthma and allergic rhinitis may be enrolled as a not statistical difference. At that time it could not be a generalization. Allergic rhinitis is a common disease in childhood [17], so if the study had been done in this age group, the AHI index would have been higher in the winter. Furthermore, we did not evaluate the complaints of the patients in this study. If we had evaluated their complaints by the subjective ESS test, results may have been more meaningful or useful.

In the light of the data obtained from this study, we found that seasons did not contribute to significant changes in AHI values. Therefore, examination of PSG does not need to be repeated in different seasons, especially among the elderly and those without asthma and allergic rhinitis.