A new study published in the Canadian Journal of Cardiology, which included data from almost half a million participants, measured an association between making cellphone calls and cardiovascular disease risk.

Specifically, the more time an individual spends making calls each week, the greater their risk of experiencing a cardiovascular event, such as stroke or heart failure.

According to the journal, published on September 4, 2024, sleep, psychological distress, and neuroticism are important drivers of the association.

What are the health implications of cellphone use?

As cellphones continue their path to world domination – there are now more cellphone contracts than humans on Earth – scientists are keen to understand their effects on health and happiness.

Research has focused on many potential effects of smartphones. For instance, there were once widespread fears that using a cellphone might cause brain cancer, and a recent World Health Organization (WHO) review of 63 studies has dismissed the link. Previously, the Food and Drug Administration (FDA) also found no data to support this link.

As smartphones are here to stay, understanding how they impact our health is clearly important. Much of the research today focuses on the impact of social media apps or chat rooms on mental health rather than the effects of mobile technology itself.

However, the latest study takes a step back and asks whether phone calls might be linked to cardiovascular risk.

To investigate, the researchers took data from 444,027 participants from the UK Biobank. This dataset included self-reported details about how much time they spent making calls on cell phones.

The scientists defined “regular” phone use as taking or making at least one call per week. More than 85% of participants fit into this classification, and the rest were defined as nonregular users.

Using hospital records, the scientists tracked participants’ health conditions and deaths over an average of 12.3 years of follow-up.

Is mobile phone use linked to cardiovascular disease?

The researchers combined cases of stroke, coronary heart disease, atrial fibrillation, and heart failure to give a composite outcome of cardiovascular disease risk.

After controlling for various factors, they found that, compared with nonregular cellphone users, regular users had a small increase in composite cardiovascular disease risk (4%). However, the longer people spent on phone calls, the larger this difference became.

Compared with people who made or received calls for five minutes or less each week, those who used their phone for:

5–29 minutes had a 3% increased risk.

30–59 minutes had a 7% increased risk.

1–3 hours had a 13% increased risk.

4–6 hours had a 15% increased risk.

6 or more hours had a 21% increased risk.

According to the study, three factors seemed to play an important part in the relationship between cell phone usage and cardiovascular disease:

Psychological distress explained 11.5% of the association.

Sleep quality 5.1%.

Neuroticism 2.3%.

“A poor sleep pattern and poor mental health may adversely affect the development of cardiovascular diseases through disrupted circadian rhythm, endocrine and metabolic disruption, and increased inflammation,” said Xianhui Qin, one of the study’s authors.

Interestingly, the scientists also found that the link between phone usage and cardiovascular disease risk was most pronounced in people who smoke and those with diabetes. The authors suggest that this link may be because “RF-EMF exposure from mobile phones in combination with smoking and diabetes may have a stronger effect in increasing [cardiovascular disease] risk.”

How cellphones raise heart disease risk

Medical News Today spoke with Cheng-Han Chen, a board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, California, United States.

Because this was an observational study, it cannot prove causation. However, we asked what factors might help explain this relationship.

“The results suggest that some of the effect might be related to phone usage effects on mental health and sleep,” explained Chen, who was not involved in the study. “There may also be confounders that affect the results.”

“For instance, the study found that increased mobile phone usage was more common in current smokers and people with diabetes. It may be that the increased risk of cardiovascular disease reported was due to the increased risk brought on by the smoking and diabetes, rather than the mobile phone usage,” he continued.

MNT also spoke to Rigved Tadwalkar, board-certified consultative cardiologist at Providence Saint John’s Health Center in Santa Monica, California, who was not involved in the study.

“It is now well known that a lot of time spent on the phone can lead to poor sleep,” he told MNT. “Poor sleep can disrupt the body’s natural circadian rhythm, leading to stress on the heart and blood vessels.”

He also explained how prolonged phone use might increase levels of stress and anxiety, which could increase blood pressure and possibly inflammation – both of which are implicated in cardiovascular disease.

Should people be worried about their cellphones?

According to Chen, “Unless these results are confirmed in future studies that better explain the relationship between mobile phone use and heart disease, I would not consider mobile phone use to be a risk factor for developing cardiovascular disease at this time.”

Tadwalkar is on the same page: “The results of this study should be taken seriously, but with a balanced perspective,” he said. “In these types of studies, there could be other factors at play that were not fully accounted for, such as the type of mobile phone technology used.”

Jim Liu, a cardiologist at The Ohio State University Wexner Medical Center, also spoke with MNT and mentioned another important caveat:

“The study only asked participants about how often they used their phones to make phone calls at baseline, which was between the years 2006 and 2010.”

Liu, who was not involved in the study, added that people now use their phones in more diverse ways, including a myriad of messaging services, live video conferencing, and a range of social media apps.

“These have probably made making actual phone calls a lot less frequent. Time spent doing other things on the phone like scrolling through social media or playing games was not assessed in this study,” he said.

“While the findings need further validation, they demonstrate the interconnectedness of modern technology and heart health, urging both clinicians and patients to be more mindful of daily habits that could influence long-term cardiovascular outcomes,” Tadwalkar told MNT. (Medical News Today)

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