Type of ear infection makes children obese

Chronic middle-ear infections in children are linked to alterations in taste buds that change their sensitivity to certain foods. This, in turn, might cause kids to eat more of these foods and push them towards obesity.

Chronic otitis media with effusion (OME) is a persistent inflammation of the middle ear, in which fluid is retained in the middle ear cavity in the absence of acute infection for three months or more. It has a high incidence in childhood and is a common cause of hearing disturbances in children. The condition  tends not to have the classic signs of acute inflammation like pain and bulging ear drum and fever, although there can be symptoms such as a clogged sensation in the ear or decreased hearing. Although most children have a good prognosis, 10 percent of affected children develop recurrent or persistent OME.

Researchers have already noted a possible link between childhood obesity and chronic OME. They speculated that related changes in taste buds might connect the two. Chronic ear infection and inflammation might affect a particular nerve, the chorda tympani, that controls taste at the front of the tongue. The nerve that supplies taste to the front two-thirds of the tongue goes right through the middle ear where the fluid is sitting. The researchers' theory is that there may be some chronic underlying inflammation of that nerve that increases sensation or increases the taste threshold in children with chronic OME and that such changes may be associated with body weight.

The researchers conducted taste tests and measured body mass index (BMI) in two groups of children: 42 with chronic OME who were having a tube inserted to drain the fluid from their ear and another 42 children without chronic OME in South Korea. Four standard taste solutions - sugar, salt, citric acid, and quinine hydrochloride - were used in chemical taste tests. It was found that children suffering from ear infections tended to be heavier than their counterparts. They also had reduced taste in the front part of the tongue, in particular, leading to a raised threshold for sweet and salt tastes. There was also a reduced ability to detect sour and bitter, but this was much less pronounced. A higher taste threshold could indicate that children with chronic OME need to eat more food to get the sweet and salty tastes they crave. And that could mean taking in more calories, resulting in a contribution to obesity.

If this, in fact, does turn out to be the case, this may be another reason to treat chronic OME. On the other hand, the relationship may not be so simple. The connection might be the other way around, with obesity helping to cause ear infections.

It's kind of a chicken-and-egg thing. Obese people do have a thicker fat padding around their ear, which can predispose them to ear infections. But to see if chronic middle-ear infection actually helps cause obesity needs further larger studies with more patients.