Dados do Trabalho

Título

Sodium intake in men with severe obstructive sleep apnea

Introdução

Water retention through high sodium intake is associated with hypertension and risk of developing obstructive sleep apnea (OSA). The displacement of fluid accumulated in the lower limbs to the periphery during the supine position increase pharyngeal collapsibility and OSA severity.

Objetivo

To evaluate the association of sodium intake with the severity of obstructive sleep apnea in men.

Métodos

Men aged 18 and 60 years previously diagnosed with severe obstructive sleep apnea defined by apnea-hypopnea index (AHI) ≥30 events per hour of sleep. Exclusion criteria were: previous treatment for apnea, predominantly central apnea, renal, cardiac, pulmonary or peripheral vascular insufficiency; use of diuretics or substances acting on the central nervous system. Anthropometric assessment and 24 hour urine collection were performed to assess sodium and aldosterone levels. Salt intake was calculated from 24 hour urinary sodium. The study was approved by ClinicalTrials.gov number: NCT01945801, and Research Ethics Committee of Hospital de Clínicas of Porto Alegre number: 13-0272.

Resultados

Were included 54 men with a mean (± SD) aged of 45±8.8 years, body mass index (BMI) 30±2.9 kg/m², blood pressure 125±8.9/85±8.6 mmHg. In 24-hour urine, 204±78mEq/24h of sodium (equivalent to 12±4.6 grams of sodium/day) and 11±5.2 µg/24h of aldosterone were detected. AHI averaged 49±19 events/hour and the minimum arterial blood oxygen saturation 77±8.8%. AHI correlated significantly with urinary sodium excretion (r=0.29; p=0.031). In the linear regression model to predict the AHI, urinary sodium was the only variable the remained significant (beta=0.41; p=0.02), controlling for BMI, age and level of urinary aldosterone. The coefficient of determination R² of the regression model shows that adjusted explain 21% of the AHI variability (p =0.027).

Conclusões

The severity of obstructive sleep apnea correlated with sodium intake. This association increase evidence that fluid displacement to the cervical region during sleep participates in the pathogenesis of OSA. Interventions reducing fluid retention could be play role in sleep apnea therapy.

Palavras-chave

Obstructive sleep apnea; fluid shift; sodium chloride