Physiological and health-related effects of 5G-relevant radiofrequency fields: A systematic review of experimental studies in humans and mammals

The introduction of the latest mobile communications standard of the fifth generation (5G) is accompanied by controversial discussions about potential health risks due to radiofrequency electromagnetic field exposure. Therefore, we conducted a systematic review of experimental and epidemiological studies investigating the physiological and health-related effects of 5G-relevant radiofrequency electromagnetic fields in humans and mammals. The review protocol has been registered in PROSPERO (CRD42022374434) and the review conforms to the PRISMA guidelines. The risk of bias and the quality of included studies were assessed using the recommended approach by the Office of Health Assessment and Translation of the National Toxicology Program. A total of 100 experimental animal and seven human controlled studies were included, analyzed, and evaluated. Narrative summaries were performed for a total of 23 topics (e.g., effects on cognition, male fertility, and thermoregulation). However, investigated species and outcomes in studies were very heterogeneous. Additionally, most studies had substantial methodological weaknesses. Only 11 studies showed a low risk of bias. In summary, for most topics, the current scientific data were inadequate to draw any conclusions about the physiological and health-related effects of radiofrequency electromagnetic fields in the investigated frequency range of 3–30 GHz. However, moderate evidence below the limit values was found for cytokine secretion in mice and low evidence was found for structural changes in the hippocampus of rats above the limit values, when taking the exposure limits presently recommended by the International Commission on Non-Ionizing Radiation Protection as the basis. Therefore, we strongly recommend high-quality systematic research. Particular attention should be paid to reasonable hypotheses, experimental studies on effects on the skin, eyes, and temperature increase, exposures to different frequencies and field strengths, as well as epidemiological studies with separate consideration of 5G (if possible).