Sleep apnoea and pulmonary hypertension in high-altitude dwellers: more than an association?

Increased pulmonary arterial pressure (PAP) is a hallmark of high-altitude exposure and, if exaggerated, may be associated with morbidity and mortality. High altitude also alters nocturnal breathing and altered nocturnal respiration has recently been reported to be associated with altered pulmonary and systemic vascular function in Andean high-altitude dwellers [1], suggesting the possibility of a causal link. Consistent with this hypothesis, in this issue of the European Respiratory Journal, LATSHANG et al. [2] report an association between pulmonary hypertension and sleep apnoea in Kyrgyz highlanders which remains significant even when adjusting for several potentially confounding factors. The authors are to be commended for their interesting study, performed in a remote area in a so far little investigated high-altitude population; however, this study also leaves open some intriguing questions.