Climatic factors such as heat and humidity that lead to dehydration can signal a future attack for gout sufferers, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Washington DC.
Gout, caused by deposits of monosodium uric crystals, causes severe pain and swelling of the joints. The attacks, which typically affect one joint over a period of a few days, most often the big toe, can also generate fever, chills, a general feeling of malaise and rapid heartbeat. Depleting the body of fluids through perspiration has been long considered a potential trigger for recurrent gout attacks.
To test the suspected effects of humidity and temperature on the chances of recurrent attacks, researchers recruited 197 individuals who had experienced a gout attack within the past year. Participants were asked to log onto a study Web site when they experienced a gout attack and complete a questionnaire on the risk factors they had experienced the two days prior (known as the hazard period). They also were asked to complete the same questionnaire on experiences over a two-day control period. Climatic data on temperature, barometric pressure, humidity and precipitation for each participant's zip code, obtained from the National Oceanic and Atmospheric Administration, was then compared between hazard period and control period with adjustments made for alcohol consumption, purine intake and diuretic use.
Results indicated that high temperature and high humidity were strongly associated with increased risk of a recurrent gout attack. The risk of recurrent attacks increased by almost two-fold when the maximum daily temperature increased from 0-53° F to 87-105° F. A similar magnitude of increased risk also was found when the humidity increased from the dew point of 4-32°F to 64-77°F. Barometric pressure and precipitation appeared to have no influence.
"Our data indicate that both high temperature and high humidity are associated with an increased risk of recurrent gout attacks," explains Yuquing Zhang, D.Sc., Professor of Medicine and Epidemiology, Boston University School of Medicine; Boston, Massachusetts and an investigator in the study. "Thus, when it's hot and humid, those with gout should consider drinking more fluids to avoid potentially painful gout attacks."
Gout afflicts about 1 in 100 people and as many as 6 - 7 percent of older men. This condition and its complications occur more often in men, women after menopause, and people with kidney disease. Gout is strongly associated with obesity, hypertension, hyperlipidemia and diabetes. Because of genetic factors, gout tends to run in some families.
The American College of Rheumatology is the professional organization for rheumatologists and health professionals who share a dedication to healing, preventing disability and curing arthritis and related rheumatic and musculoskeletal diseases. For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.
Presentation Number: 707
High Humidity and High Temperature Increase the Risk of Recurrent Gout Attacks: The Online Case-crossover Gout Study
YQ Zhang1, CE Chaisson1, CA Chen1, TE McAlindon2, DJ Hunter1. 1BUSM, Boston, MA; 2NEMC, Boston, MA
While dehydration has long been considered a potential trigger for recurrent gout attacks, few studies have examined the relation of risk factors that may cause dehydration to the risk of recurrent gout attacks. In hot and humid weather individuals can lose body fluids through perspiration. Thus, serum uric acid levels may increase due to reduced uric acid excretion.
We conducted a case-crossover study to assess a set of putative risk factors, including climatic factors, triggering recurrent gout attacks. Subjects who had experienced a gout attack within the past year were recruited online and followed-up prospectively. Participants were asked to log onto a study website when they experienced a gout attack. Risk factors on each day over the two-day period prior to an acute gout attack (hazard period) were assessed using the online questionnaire. The same questionnaire was used over each of two days during an intercritical period (control period). We obtained climatic data (i.e., temperature, barometric pressure, humidity, precipitation) from the National Oceanic and Atmospheric Administration website for the corresponding hazard and control periods according to the zip code provided by the participant. We examined the relation of each climatic factor to the risk of recurrent gout attacks using conditional logistic regression model adjusting for alcohol consumption, purine intake and diuretic use.
197 subjects completed both control and hazard period questionnaires during the follow-up period. 94% of the subjects had a confirmed history of gout according to ACR criteria. Participants were predominantly male (80.2%) and White (88.0%). Most participants had a college education (57.3%). The median time between the onset of a gout attack and logging on to the website was 2 days. High temperature and high humidity were both strongly associated with an increased risk of recurrent gout attacks (Table). Compared to the lowest quintile of maximum daily temperature (0-53 °F) over the last 2 days, the odds ratio for recurrent gout attacks for the highest quintile of maximum daily temperature (87-105 °F) was 2.0 (95% CI: 1.1-3.5) (P for trend =0.033). Compared to the lowest quintile of humidity (dew point:-4-32°F), the odds ratio for recurrent gout attacks for the highest quintile of humidity (dew point: 64-77°F) was 2.1 (95% CI: 1.2-3.7). (P for trend = 0.018). No such relation was observed for barometric pressure or precipitation.
Our results demonstrate that high temperature and high humidity are both associated with an increased risk of recurrent gout attacks. Under such weather conditions, subjects with gout may need to increase fluid intake to replace volume depletion.