Associations between air pollution, intracellular-to-extracellular water distribution, and obstructive sleep apnea manifestations

Abstract

Background: Exposure to air pollution may be a risk factor for obstructive sleep apnea (OSA) because air pollution may alter body water distribution and aggravate OSA manifestations.

Objectives: This study aimed to investigate the mediating effects of air pollution on the exacerbation of OSA severity through body water distribution.

Methods: This retrospective study analyzed body composition and polysomnographic data collected from a sleep center in Northern Taiwan. Air pollution exposure was estimated using an adjusted nearest method, registered residential addresses, and data from the databases of government air quality motioning stations. Next, regression models were employed to determine the associations between estimated air pollution exposure levels (exposure for 1, 3, 6, and 12 months), OSA manifestations (sleep-disordered breathing indices and respiratory event duration), and body fluid parameters (total body water and body water distribution). The association between air pollution and OSA risk was determined.

Results: Significant associations between OSA manifestations and short-term (1 month) exposure to PM_2.5 and PM₁₀ were identified. Similarly, significant associations were identified among total body water and body water distribution (intracellular-to-extracellular body water distribution), short-term (1 month) exposure to PM_2.5 and PM₁₀, and medium-term (3 months) exposure to PM₁₀. Body water distribution might be a mediator that aggravates OSA manifestations, and short-term exposure to PM_2.5 and PM₁₀ may be a risk factor for OSA.

Conclusion: Because exposure to PM_2.5 and PM₁₀ may be a risk factor for OSA that exacerbates OSA manifestations and exposure to particulate pollutants may affect OSA manifestations or alter body water distribution to affect OSA manifestations, mitigating exposure to particulate pollutants may improve OSA manifestations and reduce the risk of OSA. Furthermore, this study elucidated the potential mechanisms underlying the relationship between air pollution, body fluid parameters, and OSA severity.

Keywords: PM10; PM2.5; air pollution; intra-to-extracellular body water distribution; obstructive sleep apnea.

Figure 1

Mediation analyses of associations among intracellular-to-extracellular water distribution (IE distribution), short-term exposure (1 month) to particulate matter with an aerodynamic diameter of < 10 μm (PM₁₀), and OSA severity indices. Short-term exposure (1 month) to PM₁₀ was revealed to partially mediate the associations between IE distribution and OSA severity indices, including (A) apnea–hypopnea index, (B) oxygen desaturation index, (C) arousal index, and (D) respiratory event duration. The beta coefficients of the adjusted linear regression models and derived p values are presented in the path diagram. All four requirements for confirming a mediation effect were satisfied; that is, paths (A, B, C, and C)* were statistically significant. IE distribution, ratio of intracellular water to extracellular water; OSA, obstructive sleep apnea; PM₁₀, particulate matter with an aerodynamic diameter of < 10 μm; AHI, apnea–hypopnea index; ODI, oxygen desaturation index; ArI, arousal index.

Figure 2

Mediation analyses of associations among intracellular-to-extracellular water distribution (IE distribution), short-term exposure (1 month) to particulate matter with an aerodynamic diameter of < 2.5 μm (PM_2.5), and OSA severity indices. Short-term exposure (1-month) to PM_2.5 was revealed to partially mediate the associations between IE distribution and OSA severity indices, including (A) apnea–hypopnea index, (B) oxygen desaturation index, (C) arousal index, and (D) respiratory event duration. The beta coefficients of the adjusted linear regression models and derived p values are presented in the path diagram. All four requirements for confirming a mediation effect were met: that is, paths A, B, C, and C* were statistically significant. IE distribution, ratio of intracellular water to extracellular water; PM_2.5, particulate matter with an aerodynamic diameter of < 2.5 μm; AHI, apnea–hypopnea index; ODI, oxygen desaturation index; ArI, arousal index.