At last, a recent study has proved what gout sufferers have known all along: gout attacks are more common at night.
The study, published in the American College of Rheumatology journal, “Arthritis & Rheumatology,” tracked 724 American gout patients, using the Internet, over a period of one year.
Their average age was 54 years, 78% were white, 89% were male, and more than 50% were college educated. So, the participants were predominantly older, male, white, and well educated.
The study utilized 3 x 8 hour time blocks:
- overnight – midnight to 7.59 am
- daytime – 8.00 am to 3.59 pm (reference)
- evening – 4.00 pm to 11.59 pm.
And each participant was asked to record the following information when having a gout attack:
- date and hour of onset of attack
- symptoms / signs
- any medication being used
- any potential risk factors in the 24 and 48 hour periods prior to the gout attack
The results showed:
- 1433 gout attacks reported
- 733 occurred during the overnight block
- 310 occurred during the daytime block
- 390 occurred during the evening block
The risk of gout attacks during the overnight and evening blocks was then calculated with reference to the daytime block:
- The risk of gout attacks in the overnight block was 2.36 x higher than in the daytime block.
- The risk of gout attacks in the evening was 1.26 x higher than in the daytime block.
According to the study authors:
“These associations persisted among those with no alcohol use and in the lowest quintile of purine intake in the 24 hours prior to attack onset. Furthermore, these associations persisted in subgroups according to sex, age group, obesity status, diuretic use, and use of allopurinol, colchicine, and non-steroidal anti-inflammatory drugs.”
The authors concluded that:
“These findings provide the first prospective evidence that the risk of gout attacks during the night and early morning is 2.4 times higher than in the daytime. Further, these data support the purported mechanisms and historical descriptions of the nocturnal onset of gout attacks and may have implications for anti-gout prophylactic measures.”
Why Are Gout Attacks More Common At Night?
Gout is caused by higher-than-normal uric acid levels in the blood from which urate crystals form and settle in the joints and surrounding tissue. One reason given for more gout attacks at night / early morning is that the body temperature naturally falls during sleep, particularly in the feet. These lower temperatures reduce the solubility of uric acid in the blood making it easier for urate crystals to form out of the uric acid.
Sleep apnea is a condition in which the sleeper’s airway becomes completely blocked for short periods of time so that no air gets to their lungs. This can last for seconds to a minute or more, and can happen hundreds of times during the night.
Oxygen starvation builds-up with each ‘apnea’ which increases cell degradation leading to even more uric acid being produced, and, as the blood becomes more acidic as a result of less oxygen, it’s easier for uric acid crystals to be produced, resulting in a gout flare.