Tropical Weather Linked to More Emergency Department Visits, Study Finds

Tropical Weather Linked to More Emergency Department Visits, Study Finds

Moist, tropical weather types are linked to an increase in emergency department (ED) visits for people with fibromyalgia and other pain-inducing disorders, a study found.

The seven-year analysis of patient data and daily weather types also found that moist polar weather is associated with fewer ED visits.

Researchers suggest that the disparity may be due to weather-related engagement in outdoor physical activities that increase the risk of pain. Specifically, patients may be more likely to take part in more outdoor sports and activities on warmer days, they said.

The study, “Relationship between synoptic weather type and emergency department visits for different types of pain across the Triangle region of North Carolina,” was published in the International Journal of Biometeorology.

Weather, and specifically atmospheric conditions, have long been reported as inducers of pain and other symptoms in a phenomenon known as meteoropathy. Cold temperature, high humidity, and high atmospheric pressure have all been associated with increases in pain in fibromyalgia patients. However, the results of past research of meteoropathy are inconsistent.

Now, a team led by scientists at the University of Georgia and Mississippi State University sought to determine if there is a relationship between weather conditions and pain in people with fibromyalgia and other pain-inducing conditions — and if so, to quantify it. They focused on patients with four diseases: fibromyalgia, rheumatoid arthritis (RA), osteoarthritis (OA), and general back pain. Pain inducers were measured by the number of emergency department visits.

“The goal was to find a link between pain and air masses and do some type of pain forecasting,”‘ Christopher Elcik, PhD, the study’s lead researcher and a lecturer of geography and atmospheric sciences at the University of Georgia, said in a news story.

“If you take medication early enough, you can reduce some of your symptoms with a lot of these conditions. This could help people and give them a little bit of a warning,” he said.

Weather types were determined using the Spatial Synoptic Classification (SSC), which characterizes air masses — also called weather fronts — in a location to classify daily weather. Daily weather is then categorized as one of seven types: dry polar, moist polar, dry tropical, moist tropical, dry moderate, moist moderate, and transitional. The classifications are based on metrics such as temperature, dew point — one measure of humidity — and cloud cover. 

The study was carried out from 2007 to 2013 across the Triangle region of North Carolina, the location of an earlier study by Elcik that found a link between tropical weather types and migraines.

Results showed 80,427 ED visits during the study period due to one of the four conditions, with 4,680 visits being for fibromyalgia. The vast majority of visits — 73,357  or 91% — were for general back pain.

Dividing the patients into 12 age groups, the researchers found the highest number of ED visits were by people with fibromyalgia or general back pain who were between the ages 18 and 54, and over age 75. Female patients visited the ED more frequently than males for all conditions, including fibromyalgia. 

Moist tropical and moist moderate weather types corresponded to the highest number of ED visits in people with fibromyalgia, while dry tropical and moist polar weather was associated with fewer. Tropical weather was more common in summer and polar weather was more frequent in winter. Notably, however, the seasons did not have a noticeable impact on the number of fibromyalgia patients visiting the ED.

The investigators speculated that the weather-linked difference in ED visits may be related to the likelihood of individuals to participate in outdoor activities.

“We were trying to figure out if there was a physiological reason for this. Is there anything happening in the body that these types of air masses would affect? We came to the conclusion that it may not be physiological but activity based,” Elick said.

“On these warmer days when the tropical air masses move in, perhaps people are seeking outdoor activities such as golf or any other outdoor sport and that may be leading to increases in pain,”  he added. 

According to the researchers, one limitation of the study was the use of ED visits as a measure of pain instances in patients, as that criteria likely captured only severe pain. In addition, the database may have missed those who may have sought treatment from a primary care physician or clinic, the team said.

“Future research should incorporate alternative datasets (e.g., urgent care clinic records) to capture more instances of severe pain,” the researchers wrote. “Furthermore, additional research could explore other pain frequency datasets (e.g., medication sales, pain diaries) in order to identify minor instances of pain (i.e., those that do not require individuals to seek medical attention).”