Age- and Severity-Stratified Associations Among Polysomnographic Parameters, Lower Urinary Tract Symptoms, and Hormonal Markers in Men with Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) is associated with lower urinary tract symptoms (LUTS), particularly nocturia, though mechanisms including hypoxia, intrathoracic pressure changes, and hormonal alterations. While age and severity may influence these associations, stratified analyses remain limited. This study examined polysomnographic (PSG) parameters, International Prostate Symptom Score (IPSS) components, and hormonal/electrolyte markers in age- and severity-stratified men with suspected OSA. Methods: In this cross-sectional study, 104 men (mean age 60.8 ± 9.8 years) underwent PSG. Analyses were stratified by age (<60 vs. ≥60 years) and respiratory disturbance index (RDI) severity. Correlations were used to assess PSG indices, IPSS subdomains (irritative, obstructive, quality of life [QoL]), and markers including antidiuretic hormone [ADH], aldosterone, plasma renin activity [PRA], sodium, potassium. Nocturnal polyuria index (NPI ≥ 33%) was calculated in a subset of participants. Pearson correlations, ANOVA, and Kruskal–Wallis tests were used (p < 0.05), with adjustments for multiple comparisons. Results: Moderate OSA predominated (RDI 27.2 ± 20.4 events/h); nocturia affected 61.5% of the cohort. In those <60 years (n = 48), mild RDI correlated with nocturia (r = 0.42, p = 0.028), while severe RDI correlated strongly with the obstructive subscore (r = 0.96, p = 0.009). In those ≥60 years (n = 56), QoL correlated with sleep efficiency (r = 0.48, p = 0.012) and total sleep time (r = 0.46, p = 0.015). Severe RDI was associated with higher IPSS (14.5 ± 6.2 vs. 10.5 ± 4.8, p = 0.028) and nocturia (3.5 ± 1.7 vs. 2.4 ± 1.1, p = 0.02). ADH was significantly lower in severe OSA (1.4 ± 0.8 vs. 2.7 ± 1.1 pg/mL, p = 0.03). Conclusions: Age and OSA severity modulate PSG–LUTS–hormonal associations. Younger men exhibit hypoxia-linked obstructive symptoms, whereas older men experience sleep fragmentation that impacts QoL. ADH suppression is associated with severe OSA.