Do moon phases affect our health?

A sizeable proportion of the general population is convinced that certain moon phases and moon signs may impact their health as well as the onset and clinical course of diseases. Those who believe in alternative medicine tend, I guess, to belong to this group. Here is a quote from one of the many websites making such claims: Understanding moon cycles and how they affect the body can be a key to better health. To understand how the moon influences your health the first step is to realize that your human body is made up of over 60% water, and the moon affects all water on the Earth.  The moon controls the ebb and flow of the oceanic tides and it controls your human body in the same way.

There is, of course, no plausible reason for such claims and convictions, but this rarely stops the gullible. And anyway, it could be true – or couldn’t it?

This study investigated the perioperative and long-term outcome of living donor kidney transplantation (LDKT) dependent on moon phases and zodiac signs. Patient data were prospectively collected in a continuously updated kidney transplant database. Two hundred and seventy-eight consecutive patients who underwent LDKT between 1994 and December 2009 were selected for the study and retrospectively assigned to the four moon phases (new-moon, waxing-moon, full-moon, and waning-moon) and the corresponding zodiac sign (moon sign Libra), based on the date of transplantation. Pre-existing comorbidities, perioperative mortality, surgical outcome, and long-term survival data were analysed.

Of all LDKT procedures, 11.9; 39.9; 11.5; and 36.5% were performed during the new, waxing, full, and waning moon, respectively, and 6.2% during the moon sign Libra, which is believed to interfere with renal surgery. Survival rates at 1, 5, and 10 years after transplantation were 98.9, 92, and 88.7% (patient survival) and 97.4, 91.6, and 80.6% (graft survival) without any differences between all groups of lunar phases and moon signs. Overall perioperative complications and early graft loss occurred in 21.2 and 1.4%, without statistical difference (p > 0.05) between groups.

The authors concluded that moon phases and the moon sign Libra had no impact on early and long-term outcome measures following LDKT in our study. Thus, concerns of patients awaiting LDKT regarding the ideal time of surgery can be allayed, and surgery may be scheduled independently of the lunar phases.

The authors also concede that their study has some limitations. First, it is a retrospective analysis of a single transplant centre and the number of patients is not huge. In addition, due to the retrospective design of the study, no randomization of the patients was possible. However, a randomization of the patients would systematically ignore the patients preferences. Realization of such a randomized trial would therefore be challenging. As a consequence, we do not know in how many cases the transplant was scheduled according to the lunar phases on the explicit request of the patient. It would be interesting to know whether a strong desire of the patient and a corresponding fulfilment has any influence on the short- and long-term success of the surgery.

Nonsense, I hear the loonies shout: there are numerous studies confirming that the moon has a definite effect on our health!

How do you explain that?

I think there are at least two possible explanations:

1. these studies were methodologically flawed and lack independent replications;
2. it cannot be excluded that patients’ fear of the wrong moon-phase might exert a negative influence on their health, irrespective of any influence of the moon. In this case, the moon-phase itself would be irrelevant, but the fear would mimic a real phenomenon.