While it is already known that people who suffer a major concussion can lose their sense of smell temporarily, researchers have found that even minor head injuries may lead to olfactory and anxiety problems.

The study, published in the journal Brain Injury, found that even minor accidents like falling off a bike with a helmet on, taking a tumble on the ski slopes, slipping on ice and hitting one's head can provoke the same kind of problems as in major head injuries.

According to study lead author Fanny Lecuyer Giguere from the University of Montreal in Canada,

"It's important that patients report any loss of smell, because it's not something their general practitioners normally ask about," she said.

For the study, the researchers compared 20 hospital patients who had mild concussions with 22 who had broken limbs but had no concussion.

A year later, although their sense of smell was back to normal, the first group of patients had significantly more anxiety than the control group.

To test their capacity to identify smells, the researchers visited hospital patients in the alpine ski resort of Visp, Switzerland between December 2016 and February 2017. They were asked to identify synthetic odour of roses, garlic, cloves and more. A year later, the patients were sent a follow-up questionnaire.

By comparing the two groups of patients' results on the day following their injury and 12 months later, the researchers were able to determine that most who had lost their sense of smell gained it back within six months of their accident.

What did not significantly diminish, however, were their symptoms of anxiety. About 65 percent of the concussed patients reported such symptoms, researchers said.