More than 55 million people are living with dementia worldwide. That number is expected to double every 20 years.

Now, new research shows there are some surprising bad habits that may increase the risk of developing the disease.

Did you know sitting for long periods of time at work or home doesn't just increase the risk for obesity, heart disease and diabetes, but it can also raise your risk for dementia?

Researchers at UCLA found sitting for at least 12 hours a day increases your risk by 63 percent.

"The data's pretty solid that physical activity and exercise helps maintain brain health," University of Florida Clinical Neuropsychologist Glenn Smith said.

Poor oral hygiene is also a factor. A study looked at 144 participants in Milwaukee and found severe tooth loss increased their dementia risk six times more than people who lost fewer teeth.

"We all know that the mouth is the gateway to the rest of the body. So, if we can clean our mouths properly, we can certainly have a tremendous effect, not only in dentistry, but also in overall health," PlaqueHD inventor and Orthodontist Lawrence Hier said.

Other bad habits include not getting seven to nine hours of sleep per night, drinking too much alcohol and isolating yourself.

"The effect of social isolation and loneliness on our health is as powerful as things like smoking, high blood pressure, obesity," Psychiatrist Richard S. Schwartz said.

So, get some shut-eye, drink in moderation and call a friend to keep your brain in tip-top shape.

Skipping vaccines could also increase your dementia risk.

A study found those over 65 who got a flu shot lowered their risk for Alzheimer's, a common form of dementia, by 40 percent and those who got a Pneumonia vaccine were 30 percent less likely to develop dementia.