A recent study found that increased ultraviolet light exposure is linked with reduced inpatient mortality due to Clostridium difficile infection.
Clostridium difficile infection (CDI) occurs when a disruption of the normal bacteria in the colon takes place, thus allowing clostridium difficile to take up residence and overpopulate.
CDI is the most common source of infectious colitis in the United States. In fact, CDI has been associated with a mortality rate of 6.9% at 30 days after diagnosis.
Symptoms associated with CDI include but are not limited to: abdominal pain, diarrhea, severe inflammation of the colon (colitis), fever, vomiting and dehydration. In colitis cases, individuals may experience extensive damage to the intestinal lining, potentially resulting in sepsis and an increased risk of mortality.
Vitamin D deficiency is associated with more aggressive cases of CDI. This may be related to the antimicrobial effect of vitamin D.
Since ultraviolet B (UVB) exposure is the primary source of vitamin D production, researchers theorize that increased ultraviolet light exposure may decrease mortality related to CDI.
In a recent epidemiological study, researchers aimed to determine if UV light exposure is related to CDI inpatient mortality. They used the UV index to assess UV light exposure. The UV index was determined by the location of CDI related hospitalizations.
UV index is an international standard predictor of the strength of UV radiation from the sun at a specific time and place. It is measured on a scale of 1-11, with each unit indicating an increased risk of sun burn.
The researchers found the overall mortality rate for individuals hospitalized with primary or secondary CDI diagnosis was at 9%. UV exposure produced a 3% decreased risk of inpatient mortality risk per unit of UV exposure (p < 0.001). A seasonal effect was also present, with an 11% increased risk of inpatient mortality from January through March, and a 5% decreased risk of mortality occurred between the months of July through September.
The researchers concluded,
“In this ecological study of NIS data from 2004–2011, we found an inverse relationship between inpatient mortality and the average yearly UV Index exposure in patients with a diagnosis of CDI.”