Watching Television Increases Risk of GERD

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A bidirectional Mendelian randomization (MR) analysis showed a causal relationship between leisure television watching and an increased risk of gastroesophageal reflux disease (GERD), which was further increased by the number of cigarettes smoked per day.

“GERD impairs the patient’s quality of life and increases the risk of other esophageal complications, such as esophagitis, esophageal strictures, Barrett’s esophagus, and esophageal adenocarcinoma,” wrote a group of investigators from Renmin Hospital of Wuhan University. “Therefore, determining the potentially modifiable risk factors of GERD is important to prevent and manage the disease in clinical practice.”

Prior research has linked leisure sedentary behaviors (LSB)—such as watching television—and physical activity to GERD, although these findings are considered controversial and inconsistent. For example, some studies report regular exercise can reduce the symptoms of GERD, while others report no effect at all.

To evaluate these causal relationships and explore the potential mechanisms, investigators collected data on physical activity/LSB, GERD, and 4 common risk factors: alcoholic drinks per week, cigarettes smoked per day, total cholesterol, and triglycerides. Physical activity included self-reported moderate to vigorous exercise, strenuous sports or other exercises, and accelerometer-measured acceleration averages. LSB data incorporated leisure television watching, leisure computer use, and driving.

Other information collected in the dataset included age, sex, genomic principal components, a diagnosis of hypertension and/or diabetes, and body mass index (BMI).

The analysis showed a significantly increased risk of developing GERD for those who spent leisure time watching television. As the longer time spent engaging in television viewing is linked to both higher intention of smoking and a higher volume of cigarettes smoked, smoking may further increase the risk of developing GERD for those who spend leisure time watching television.

Smoking, a common risk factor for GERD, stimulates the production of gastric acid, which can increase the symptoms of GERD, and damages the membranes in the esophagus.

Potential mechanisms for the relationship between television watching and GERD include the weakening of the crural diaphragm, which plays an important role in the anti-reflux barrier and could be compromised due to prolonged sedentary behaviors. Additionally, LSB promotes low-grade chronic systemic inflammation and increases the levels of inflammatory factors, which can encourage the development of the condition. Additionally, television watching is often associated with poor physical and mental health, including anxiety and depression, as it is a less reflective and communicative form of entertainment compared with computer use and driving.

There was no causal effect on physical activity on GERD.

Despite these promising findings, investigators mentioned several limitations, the first of which was the many variables that could influence physical activity/LSB and GERD, potentially leading to biased results. Although the mediation analysis showed the causal effect of leisure television watching and GERD was partially mediated by smoking, the genetic impact of possible mediators was not evaluated. Lastly, the generalizability of the results may have been impacted by the homogeneity of the sample, which was predominantly comprised of European participants.

“These findings suggest that reducing leisure time spent on watching television may be a beneficial approach for preventing GERD, especially in smoking populations,” investigators concluded.