Is the Gender Difference in the Association Between Obesity and OSAS Really Less in Women?

Obstructive sleep apnoea syndrome (OSAS) is a common sleep disorder characterized by recurrent episodes of partial or complete upper airway obstruction, resulting in sleep disruption and cardiovascular comorbidity. It is recognized that OSAS is strongly associated with obesity and has a higher prevalence in the male gender. However, emerging evidence suggests that OSAS is significantly underdiagnosed in women due to different clinical presentations and physiological characteristics and that the gender difference may not be so high. Given that obesity is an important risk factor for OSAS, it is important to investigate gender-based variations in the effect of obesity on OSAS prevalence and severity. In conventional OSAS epidemiology, the male-to-female ratio is generally estimated to be 2:1 and even 4:1 in some studies. This disparity has been attributed to differences in body fat distribution, airway anatomy, and hormonal influences. It has been reported that the upper airway walls are harder in women than in men, Hence women are less susceptible to collapse, and men have more pharyngeal collapse sensitivity. In addition, female hormones are thought to help prevent airway collapse by increasing the tone of the upper airway dilator muscles (1,2). Body fat distribution characteristics in men and women, such as androgenic-gynoid, central-peripheral, visceral-subcutaneous, may explain some of the sex-related differences in the relationship between obesity and OSAS. Men typically have greater upper airway collapsibility due to increased fat deposition in the neck region, whereas women tend to accumulate adipose tissue peripherally rather than centrally. However, this may change in post-menopausal women due to hormonal differences and the pattern of adiposity tends to be more androgenic-centralised. Recent evidence suggests that postmenopausal women experience a significant increase in the risk of OSAS, possibly due to a decrease in protective levels of oestrogen and progesterone. This suggests the importance of age in the differences (3). OSAS symptoms may differ according to gender. While typical symptoms such as diagnosed apnoea, loud snoring, and excessive daytime sleepiness are observed in men, non-classical symptoms such as insomnia, depression, and fatigue may be more prominent in women. Therefore, many women may be diagnosed with different diagnoses such as chronic fatigue syndrome and mood disorders. This is an important factor in the underdiagnosis of OSAS in women (1). It is clear that there is a need to focus on approaches independent of male gender bias in OSAS. The aim should be to introduce more inclusive screening methods for the female gender that do not ignore postmenopausal hormonal changes and atypical OSAS symptoms that may increase the risk of OSAS. In addition, anthropometric measurements such as waist-to-hip ratio, waist-to-height ratio, and visceral fat assessment should be considered for prioritised use over traditional anthropometric measurements such as BMI (4). In conclusion, although OSAS is generally accepted as a male gender predominant condition, increasing data suggest that symptoms and risk factors vary depending on gender. In this context, OSAS is underdiagnosed in women. Early diagnosis and treatment of OSAS in female patients requires more specialized approaches that take into account age, hormonal and regional factors.