Can snoring induce or worsen obstructive sleep apnea?

Snoring and sleep apneas are breathing disorders intimately associated during sleep. Most snorers are 'simple' or 'nonapneic', as the prevalence of snoring is much higher than that of sleep apneas. The vibrations transmitted to the pharyngeal structures by snoring span a large range of frequencies, while the energy transmitted may reach high values. A deleterious effect of these vibrations can therefore be considered. In 1983 a group of investigators from Bologna described five cases of heavy snorers of increasing severity, suggesting that they correspond to the natural history of 'heavy snorers' disease'. The present article reviews the data published since 1983 in favor of this hypothesis: anatomic lesions of the upper airway mucosa, pharyngeal muscles and nerves, and clinical observations in snorers. The conclusion stresses the absence of ultimate proof in favor of this attractive hypothesis: we lack the demonstration of a significant increase of the incidence of sleep apnea in a group of nonapneic snorers in a longitudinal follow-up study.