“As many as five million Americans age 65 and older may have Alzheimer’s Disease, and that number is expected to double for every five-year interval beyond age 65.” — the National Institute of Neurologic Disorders and Stroke.

While Alzheimer’s is the most common form of dementia, it is not the only form.

Risk factors for all kinds of dementia include, age, alcohol use, smoking, atherosclerosis, diabetes, hypertension, and genetics. However, researchers have found some startling connections that show other surprising factors that can heighten your risk:

Risk Factor #1: Anticholinergic Drugs

A recent study published in JAMA Neurology found that a class of drugs called anticholinergics is associated with poorer cognition and changes in brain structure and function. Which drugs are we talking about here? Some you would never suspect: over-the-counter sleep aids, sedating allergy meds such as Benadryl, sedating pain meds like Tylenol PM, and prescription meds such as some antidepressants and urinary incontinence treatments. You can find the complete list here.

“We didn’t look at the amount each study participant took; just that they took them. However, we did see the risk heighten in the person who took more than one kind of anticholinergic,” says lead author Shannon Risacher, Ph.D., assistant professor of radiology and imaging sciences, Indiana University School of Medicine. The hypothesis is that these drugs block the ability of the neurotransmitter acetylcholine to act with the receptors.

The study also showed that once people went off these meds, their risk fell to normal levels.

Before you panic, Dr. Risacher also points out for now that they have found a correlation between drugs and cognitive decline, but they have not found definitively that one causes the other. “Don’t go off any prescribed medications without checking with your physician first. These drugs are used for important reasons, all of which need to be treated in order to have healthy lives. Ask about alternative therapies or have your physician monitor your cognitive function,” she says.

Risk Factor #2: Lack of Vitamin D

Researchers have found that, among study participants, older adults with starting blood levels of vitamin D that were below 20 ng/mL had an increased risk of cognitive decline in:

• Episodic memory: Memory of past autobiographical events.

• Semantic memory: Memory of specific learned facts or general knowledge.

• Visuospatial ability: The ability to orient objects in the space around you using visual cues. This involves depth perception, the ability to find one's way home, and reading, among other things.

• Executive function: Reasoning, problem solving, planning, and following directions.

“It is unknown if vitamin D supplements will slow or prevent cognitive decline; randomized control trials are needed to test this. In the meantime, older adults with low vitamin D status, in consultation with their doctor, should consider vitamin D supplements, which are relatively safe, presuming the upper tolerable limit of 4000 IU per day is not exceeded,” says study researcher Joshua W. Miller, PhD, Professor and Chair, Department of Nutritional Sciences, Rutgers, The State University of New Jersey.

If you prefer natural sources, Vitamin D is found in:

Fatty fish (tuna, mackerel, swordfish, and salmon)

Foods fortified with vitamin D, such as dairy products, orange juice, soy milk, yogurt, cereals

Beef liver

Cod liver oil

Swiss cheese

Egg yolks

Risk Factor #3: Heartburn Meds

Heartburn medications with proton pump inhibitors (PPIs) are among the most commonly used drugs worldwide but a German study has found a possible link among older adults between dementia and PPIs such as Prilosec and Prevacid. (You can read the complete medication list here.) The study concluded that “the avoidance of PPI medication may prevent the development of dementia.”

Lewis Kuller, MD, PhD, Professor and past chair of the Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, urges a measured response, explaining, “This is a good study, based on solid science. However, we don’t know yet if the relationship is because PPIs lead to dementia, or that that the people who take these meds may be at higher risk for dementia anyway — smokers, heavy drinkers, obesity.”

So what’s a person do after a night of too many tacos Guadalajara? “Be prudent,” says Dr. Kuller. “You shouldn’t stop taking these medications without speaking with your physician first but you should be wary about taking them in the long term. If you need the drug, use it, but don’t take it just for mild symptoms.

Read more on Grandparents.com: