Earlier this year, a group of international experts on dementia commissioned by The Lancet, a British medical journal, to study “dementia prevention, intervention and care,” reported their findings. Part of the report took a fresh look at risk factors for dementia and found that more than a third of our risk is likely modifiable. That is, we can do something about it, as opposed to risk controlled by genetics. Most of the modifiable risk factors have been discussed in previous columns (increasing formal education, controlling high blood pressure and diabetes, exercising regularly, avoiding obesity and smoking, treating depression adequately and being socially engaged). But the single strongest potentially modifiable risk factor in their research was a surprise to me and many others — hearing loss. According to their calculations, 35 percent of dementia can be blamed on the nine risk factors listed above. Among those factors, more than one-fourth is linked to hearing loss.