Two decade Taiwan study reveals mild link between mobile phone usage and brain cancer incidence

By Dr. Sanchari Sinha Dutta, Ph.D.Jul 5 2023

A population-based study conducted on Taiwanese residents over a period of 20 years finds a weak positive association between mobile phone usage and incidence and mortality related to malignant neoplasm of the brain (MNB). 

The study is published in the journal Cancers.

Study: Incidence and Mortality of Malignant Brain Tumors after 20 Years of Mobile Use. Image Credit: Little Pig Studio / Shutterstock

Background

A sharp rise in the usage of mobile or smartphones has been observed globally in recent decades. Despite smartphones' many useful functions in everyday life, there remains a concern about the potential effect of mobile radiation on human health.

Some evidence suggests that radio frequency waves emitted from electronic devices like smartphones can target the brain and increase brain cancer risk. In 2011, the International Agency for Research on Cancers classified radiofrequency electromagnetic non-ionizing radiations as "possibly carcinogenic to humans."

In contrast to these observations, a large pool of evidence indicates that smartphone usage is not associated with higher incidence and mortality of brain cancers. According to the 2020 guidelines provided by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), there is no significant effect of radiofrequency radiation on the development and progression of cancer.

In the current study, scientists have investigated whether smartphone usage for a period of 20 years has any effect on the incidence and mortality related to malignant brain cancers in Taiwan.

Study design

This population-based study was conducted between January 2000 and December 2019. The data on brain cancer incidence and mortality rate was collected from Taiwan Cancer Registry, and the data on smartphone usage was collected from the National Communications Commission.

Relevant statistical analyses were conducted to investigate the association between smartphone usage and brain cancer incidence and mortality. In addition, the average percentage change in the number of smartphone users was calculated each year.

Important observations

The study analysis revealed that the average annual percentage change in the number of smartphone users has increased by 63.4 per 100,000 persons, and the numbers of brain cancer incidences and deaths have increased by 9.1 and 62 per 100,000 persons, respectively, over a period of 20 years in Taiwan.

Similarly, the compound annual growth rates of smartphone users, brain cancer incidence, and brain cancer deaths were estimated to be 1.95, 1.07, and 2.30, respectively, during the study period. These observations indicate a positive growth rate for all estimated parameters.

Two statistical models were used in the study to investigate the study question. Model 1 revealed that the number of smartphone users has a slight impact on brain cancer incidence rate at a significance level of 5%. With every one-million increase in the number of smartphone users, there was an increase of 0.35 cancer incidences per 100,000 persons.   

Model 2 indicated a weak positive association between smartphone usage and brain cancer mortality at a significance level of only 1%. With every one-million increase in the number of smartphone users, there was an increase of 0.95 cancer deaths per 100,000 persons.       

The correlation analysis of model 1-derived data indicated that with every percentage change in the number of smartphone users, brain cancer incidence rate increased by 0.5 percent in 2018. Similarly, the analysis of model 2 data revealed that with every percentage change in the number of smartphone users, brain cancer death rate increased by 2.4 percent in 2019.  

Study significance

The study finds an increasing trend in the number of smartphone users during 2000 – 2019 in Taiwan, which is accompanied by a slight increase in brain cancer incidence and mortality rates. In other words, the study finds a weak and non-significant association between smartphone usage and brain cancer incidence and mortality.

Newly emerging technologies have higher data transmission rates and frequencies compared to existing technologies. Keeping this in mind, the scientists mention that the intensity and duration of radiation exposure should be considered while exploring the impact of smartphone usage on cancer risk.

Limitations

The investigation confronted several limitations: the utilized data originated from a single region, comprehensive mobile phone user information was inaccessible, and the study spanned merely two decades.

Beyond this, the investigation focussed on mobile phones exclusively as the probing variable for assessing MNB incidence and MNB-related mortality, neglecting other potential confounding variables and risk aspects likely implicated in brain tumor development and subsequent fatality. For instance, prolonged interaction with ionizing, not non-ionizing radiation agents, genetic susceptibilities, exposure to chemicals, and inherited disorders primarily come to mind.

Furthermore, negative environmental influences and various lifestyle elements could also play a part. Consequently, for a precise, comprehensive analysis of MNB incidence and mortality root causes, all these factors warrant consideration. Also, our study did not delve into the age-related distribution facets of mobile users to determine their correlation with MNB, a pivotal omission as cancer incidence typically escalates significantly among middle-aged individuals and seniors.

Moreover, the length of radiation exposure remains an important aspect to scrutinize for a superior understanding of the latency period of brain cancer in future research. Concurrently, disseminating potential preventative measures is essential to safeguard the Taiwanese population's health.

Conclusion

This expansive, 20-year demographic study unveiled patterns in the occurrence of MNB and MNB-related fatality linked to mobile phone utilization in Taiwan. The data revealed a rising trend in mobile phone users during the study duration, accompanied by a mild increment in MNB incidence and fatality rates. Compound annual growth rates further echo these findings, spotlighting the steady surge in mobile phone users and a corresponding escalation in MNB cases and mortalities.

These results hint at a tenuous correlation between the escalating count of mobile phone users and increasing MNB rates, with no significant connection observed between MNB cases, deaths, and mobile phone usage.

Broadly, the literature in this realm is extensive and contains mixed opinions, yet primarily, it offers scant or no evidence of the correlation between mobile phone users and the emergence of brain tumors and death.

Crucially, it is essential to concede that definitive conclusions cannot be drawn at this point, necessitating further research to yield more conclusive results.

Considering potential hazards linked to burgeoning technologies such as 5G, featuring enhanced data transmission speeds and frequencies, it is imperative to scrutinize radiation exposure levels and durations when evaluating the link between mobile phone usage and cancer.

Upcoming studies should delve into various age brackets of mobile phone users and scrutinize radiation exposure duration to enhance understanding of their potential links with MNB, given that the latency period for brain cancer can span 10 to 50 years.

Persistent research in this field will enrich our understanding of potential risks and assist in formulating safer mobile phone usage protocols moving forward.

Lastly, further profound investigations into other related confounding variables and risk factors potentially implicated in MNB development are crucial for grasping the complete picture.