About 14% (740 million) of the world’s adults have experienced hearing sounds in their ears or heads that did not come from an external source. European scientists estimated the global prevalence of the condition known as tinnitus, and recently published the results of their study in JAMA Neurology. The study found that tinnitus is more common as people get older, and that neither sex is more predisposed to having it. However, there is an intriguing regional disparity in the prevalence of the condition, about which much remains a mystery.
Tinnitus is almost always a manifestation of another problem, but its causes (etiology) can be very diverse. Sometimes tinnitus comes from an auditory lesion caused by extreme or constant noise, an episode of sudden stress, earwax accumulation, or something more serious like a tumor. This diversity of associated disorders complicates tinnitus research, but scientists agree that the first step is understanding how many people are affected.
Carlotta Micaela Jarach, an epidemiologist at the Mario Negri Institute (Milan, Italy), is the lead author of the study. “Our estimates indicate that, globally, one in seven adults report having experienced tinnitus,” said Jarach. In more severe cases, where tinnitus significantly interferes with quality of life, the figure is lower. She said, “We found severe tinnitus in about 2% of the population.” That’s about 120 million people who live with intense, sometimes constant and disabling ringing in the ears.
We found severe tinnitus in about 2% of the populationCarlotta Micaela Jarach, an epidemiologist with the Mario Negri Institute
The researchers first reviewed hundreds of tinnitus studies published in scientific journals. They then selected 100 papers for detailed study, some conducted in individual countries and some that had a regional scope. The researchers extrapolated the data obtained from the 100 studies to the global population in order to approximate the worldwide prevalence of tinnitus. But the very nature of tinnitus makes it difficult to know exactly how many people suffer from the condition.
Generally, tinnitus accompanies, precedes or follows hearing loss or impairment. This is one of the main problems with studying tinnitus. While there are instruments to measure and record detailed information about hearing loss, there is no way to objectively measure the ringing or buzzing that is characteristic of tinnitus – it’s a subjective sensation. To determine prevalence, researchers have to use questionnaires that rely on the responses of the survey participants. This is why the authors of this study said they had to be cautious with data obtained from minors.
A little over 14% of adults report having experienced tinnitus, similar to the 13.6% of minors who also said they had the condition, which seems to contradict the connection between hearing loss and aging. But Silvano Gallus, head of the laboratory of Lifestyle Epidemiology at the Mario Negri Institute and coauthor of the study, is cautious when assessing subjective data collected from young people. “Our hypothesis is that the way the question is posed plays an important role. In the absence of an objective diagnostic instrument that can attest to the presence of tinnitus, we must use validated questionnaires to identify the severity of the condition,” he told EL PAÍS.
“The studies of tinnitus in children that we analyzed mostly asked general questions about hearing a whistling or ringing sound,” said Gallus. “We believe this type of general question leads to overestimation because many children will answer yes, even if they do not have tinnitus.” Gallus. If the 13.6% number is to be believed, then 325 million more people suffering from tinnitus would have to be added to the global total. But the authors of this study insist that the data for children is not credible.
The prevalence of tinnitus seems to be similar in both sexes, while it increases significantly with ageBerthold Langguth, professor of psychiatry and psychotherapy at the University of Regensbur
When the data is stratified into adult age groups, the increasing prevalence of tinnitus with age becomes even clearer. The prevalence among young adults (18-44) is 9.7%, rising to 13.7% in middle-aged adults (44-65), and rising again to 23.6% in adults over 65. The differences are even greater for severe tinnitus – its prevalence among the elderly is up to 20 times higher than among younger adults.
However, there are hardly any gender-related differences, stated a press release from one of the study authors, Berthold Langguth, professor of psychiatry and psychotherapy at the University of Regensburg (Germany). “We have found that the prevalence of tinnitus appears to be similar in both sexes, while it increases significantly with age.” As one of the leading European experts on tinnitus, Langguth says. “Given the aging of the world’s population, tinnitus will be a growing problem in the future.” But aside from teaching patients how to cope with the condition, not much progress has been made regarding drugs or treatments for tinnitus.
The study created a map to provide a visual aid for the prevalence of tinnitus around the world. Asia, Oceania, North America and Europe all have similar percentages: 13-16%. Latin America has the highest prevalence with 21.9%, and Africa has the lowest, with 5.2%. These outliers are not easy to explain due to the very low availability of research and data for these regions. However, it’s clear that ringing in the ears does not discriminate among social classes. Using gross domestic product per capita data, the study found that the rich and the poor suffer equally from tinnitus.