Effects of long-term low-dose 2.45 GHz microwave electromagnetic radiation on vulnerable organs in humans: a retrospective study based on patients receiving microwave diathermies in the Department of Rehabilitation Medicine.

Purpose: To retrospectively observe the effects of long-term low-dose 2.45 GHz microwave electromagnetic radiation on human vulnerable organs.

Methods: This single-center, retrospective cohort study investigated patients who received long-term (20-100 times of microwave therapy within three months) low-dose (≤20 W) microwave therapy in our department five years ago. Patients were identified and followed up using a rehabilitation treatment management system. Adverse events or diseases that developed after microwave treatment were collected. Based on the number of microwave exposures, patients were divided into two groups: the multiple irradiation group (20-50 sessions) and the ultra-multiple irradiation group (50-100 sessions). The incidence of irreversible damage (ocular lesions, nervous system diseases, reproductive system diseases, cardiovascular system diseases, tumors, or early precancerous lesions) within five years after treatment completion was compared between the two groups.

Results: A total of 113 valid cases were analyzed. Sixteen adverse events occurred, including two cases related to tumors, nine cases related to cardiovascular and cerebrovascular diseases, five cases related to metabolic diseases, and one case related to nervous system diseases. One patient had multiple conditions. There was no significant difference in the incidence of adverse events between the multiple irradiation group and the ultra-multiple irradiation group (p = .161, OR = 0.307, 95% CI 0.088-1.025). Logistics regression analysis revealed that the number of microwave treatments, treatment frequency per week, and patient gender was not a significant risk factor for adverse events (p = .100, OR = 0.972, 95% CI 0.938-1.006; p = .896, OR = 1.028, 95% CI 0.679-1.575; p = .960, OR = 1.039, 95% CI 0.212-4.609). Advanced age and obesity might be contributing factors for adverse events (p = .001, OR = 0.923, 95% CI 0.877-0.965; p = .002, OR = 0.064, 95% CI 0.009-0.348).

Conclusions: Based on this study, receiving less than 100 sessions of low-dose microwave therapy within three months appears to be safe. Advanced age and obesity might increase the risk of adverse events. Due to the deviation that may be caused by the small sample size of this study, it is necessary to carry out prospective randomized controlled studies with larger samples in the future for further verification.