SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science I. Sleep Disorders – Breathing
0362
IS SLEEP APNEA A WINTER DISEASE? METEOROLOGICAL
AND SLEEP LABORATORY EVIDENCE COLLECTED OVER
ONE DECADE
Cassol CM 1 , Breitenbach TC 1 , Fischer MK 1 , Pires GN 5 , Silva FA 2 ,
Oliveira GR 1 , Vidal MF 1 , Bós AG 3 , Lenz MD 4 , Martinez D 1,4
1
Cardiology Division, Hospital de Clínicas de Porto Alegre /
Universidade Federal do Sul, Porto Alegre, Brazil, 2 Estatística,
Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil,
3
Geriatrics and Gerontology, Pontifícia Universidade Católica do Rio
Grande do Sul, Porto Alegre, Brazil, 4 Sleep, Sleep Clinic, Porto Alegre,
Brazil, 5 Psicobiologia, Universidade Federal de São Paulo, São Paulo,
Brazil
Introduction: Sleep apnea is associated with cardiovascular outcomes
that are more frequent in winter. The hypothesis that apnea-hypopnea
index (AHI) of patients undergoing polysomnography in the winter may
be higher than in summer was tested.
Methods: The retrospectively analyzed database included 7,523 patients
of both genders undergoing in-laboratory baseline polysomnography
to investigate any complaint of disordered sleep, during one decade,
between January 2000 and December 2009. Data on climate, air pollution,
and mortality were obtained from official organs of Porto Alegre,
Brazil. AHI was the main outcome variable.
Results: The cosinor analysis confirmed the existence of a circannual
pattern for AHI, with acrophase in August, austral winter, and nadir during
February, austral summer. The lowest oxygen saturation showed inverse
pattern with acrophase in February and nadir in August (p