When health stories circulate in the media, it’s often because of a press release issued by an academic institution or the publication of an abstract on a science-based website has attracted attention. And, as we all know, attention-grabbing headlines work. But they also have the potential to cause harm or worry. This can happen when people don’t read beyond the headline or summary information.
According to the study abstract, it’s the dual sensory impairment that is associated with stronger depression. Yet some of the articles mention it happening with hearing or vision loss, not dual loss.
“[…] women who suffer from hearing or sight loss, or dual sensory loss are more than twice as likely to report depression and anxiety as men who experience the same issues.”
This article refers to “hearing or sight loss,” or “dual loss.” It compares the the likelihood of reporting depression with men with the same issues, rather than with women without those issues.
“Women with dual sensory impairment were almost three and a half times more likely to report depression or anxiety than those who did not have any impairments.”
This article refers not to being “twice as likely,” but “almost three and a half times more likely” to report depression or anxiety. It compares women with dual sensory loss to women without sensory loss.
But what should we always remember when cross-referencing data? That’s right: Correlation does not imply causality. Consider these two statements: Jane’s hair is brown. Jane has hearing loss. Both statements are true, but one fact has not caused the other. And yet, two sets of data have been presented and made to read as though women with sensory loss are twice as likely (as men) to suffer depression (as a result of their sensory loss). But if you read these statements properly, they’re merely saying that women just tend to report their depression more than men.
“Correlation does not imply causality.”
The study, conducted at Anglia Ruskin University (ARU) in England, was published in the International Journal of Geriatric Psychiatry in March 2021. Researchers used secondary data from 23,089 adults (15–103 years, 45.9 percent men) who had responded to a Spanish National Health Survey in 2017. This is the first red flag: utilizing secondary data.
The information collection method for the Spanish National Health Survey included computer-assisted personal interviews. These were sometimes supplemented with telephone interviews. Data was gathered on ability levels for vision (ability to see, even using glasses or contact lenses) and hearing (ability to hear, either in a quiet place or a louder place, even when using a hearing aid).
For the ARU study, researchers cross-referenced two data sets. The self-reporting of “experiencing vision, hearing, or dual sensory impairment,” and the self-reporting of “experiencing depression and anxiety.” The questions in the survey were independent of one another.
Lead author Professor Shahina Pardhan’s abstract says, “Dual sensory impairment (hearing and seeing) is/are associated with increased depression and anxiety. Women with dual sensory impairment showed stronger associations compared to men among adults in Spain.”
The study concluded that there were “associations” between sensory impairments and depression and anxiety. Another conclusion was that “Interventions are needed to address vision and/or hearing impairment in order to reduce anxiety and depression, especially in women.” This seems to suggest that they are implying a causal link between sensory impairment and depression and anxiety. Unfortunately, the study did not differentiate between people with an aided impairment and those who were unaided.
The report on the National Health Survey 2017 Methodology outlines the sensory data:
“An attempt is made to measure functional (sensory) limitations that affect the health status of the population in terms of ability to function, regardless of the reason behind the limitation.”
Therefore, because the Spanish National Health Survey did not refer to the causes of hearing loss experienced, or the types of visual impairments, they could not be considered in the ARU study. And yet, causes and types of impairments would have huge effects on whether or not anxiety and depression were linked to sensory impairment. If you think your hearing loss or sight are likely to deteriorate, it’s understandable that you would feel more anxious about it than someone who was told their loss would remain stable.
It is easy to assume that people who can’t see or hear well might be anxious or depressed. This could be because of the loss, the possibility of the loss getting worse, personal safety, or other things entirely. But you would need primary data about how respondents perceive the causes of their anxiety or depression in order to look for a causal link.
“It is easy to assume that people who can’t see or hear well might be anxious or depressed.”
Also, the Spanish survey referred to the self-reporting of depression or anxiety rather than an actual diagnosis of these conditions by a medical professional.
So, the moral of this story is, don’t be triggered by alarming headlines. If you’re interested in the topic, read around the story and go to the original source if possible.
Read more: Managing hearing loss and mental health