As far back as the 17th century, people who suffered from gout swore they suffered more gout attacks at night. But even though this complaint has been around for centuries, no one actually had conducted research to see if it was true. Until now.
For the study, researchers at Massachusetts General Hospital and Harvard Medical School recruited 724 patients who had been diagnosed with gout. They were mostly male and white, their median age was 54 and they had been suffering from gout for an average of five years. To find out if gout attacks were more frequent at certain times, the researchers divided the day into three blocks of time: Block One from midnight to 7:59 a.m., Block Two from 8 a.m. until 3:59 p.m. and Block Three from 4 p.m. until 11:59 p.m. Over the course of the study, the participants suffered 1,433 gout attacks.
After assigning the gout attacks to the different time blocks, the researchers discovered that Block One (the night shift) contained 733 attacks, while Block Two had 310 attacks and Block Three had 390. In other words, the risk of a gout attack was more than twice as high during the night and early morning hours than during the day or evening. The researchers also adjusted for other factors and reported there did not appear to be any connection between the attacks and the patients’ intake of alcohol or purine-rich foods (a high-purine diet can raise uric acid levels in the body, which can lead to gout). Age, sex, obesity and medication use also did not seem to affect the timing of the attacks.
The researchers were unable to give a definitive explanation for why gout attacks occur more frequently at night, but they offered several possible reasons. First, it’s well known that body temperatures drop during the night, so it’s possible that lower body temperatures promote the formation of the sharp, needle-like uric acid crystals that cause gout pain. Also, blood cortisol levels drop after a person falls asleep—a possible cause of morning stiffness. Another possibility has to do with sleep apnea (a disorder in which a person has pauses in breathing or shallow breaths during sleep). Half of all sleep apnea patients have what’s known as hyperuricemia, a condition characterized by abnormally high levels of uric acid in the blood. For this reason, sleep apnea might be related to gout attacks.
All these possibilities will be explored in further research. The first step was to find out if gout attacks really occur more frequently at night. Now that researchers know they do, they can move on to possibly developing new measures for preventing gout attacks, especially after bedtime.