Onset of spontaneous pneumothorax and the synodic lunar cycle.

The relation between spontaneous pneumothorax events and synodic lunar cycle was studied in a retrospective analysis of patients with a first or recurrent spontaneous pneumothorax. The study included a total of 244 patients, 203 males and 41 females. The data were arranged along the first (new moon) to 28th day (one day before another new moon) of the synodic lunar cycle. Periodogram analysis revealed a 14-day rhythm, significant for the male and pooled sample. Cosinor analysis found the whole synodic lunar cycle and its 2nd, 4th and 5th harmonics as significant. Maximal accumulation of cases happened 1 week before and 1 week after the new moon. Mechanisms of a putative moon influence are not clear. Copyright 2001 Harcourt Publishers Ltd.