Updated August 11, 2014.

The health risks of smoking tobacco are many and well-established- smoking is strongly linked to cancer, heart disease, COPD, emphysema and a host of other conditions. But did you know that smoking also has been connected to your brain health?

According to the World Health Organization (WHO), smoking tobacco is a significant risk factor for the development of dementia- a condition where your brain functioning deteriorates.

Types of dementia include Alzheimer's disease, vascular dementia, frontotemporal dementia and Lewy body dementia.

The Risk of Smoking Tobacco

The WHO recently issued a document outlining the connection between tobacco smoking and dementia. They estimate that "14% of Alzheimer's disease cases worldwide are potentially attributed to smoking" (WHO 2014).

The Action on Smoking and Health Scotland cites research that heavy tobacco smokers may be as much as 70% more likely to develop dementia.

Additionally, there appears to be a relationship between how much a person smokes and their risk of dementia. Research points to a higher risk for those who smoke more. This suggests that, although quitting smoking is best, even cutting down is worthwhile.

In age-related cognitive decline (where older adults experience a gradual decline in thinking and memory but are still able to function well), smoking has been correlated with a faster decrease in memory and executive functioning skills.

Does Quitting Decrease the Dementia Risk? 

Quitting smoking appears to be beneficial for brain health.

Some research has shown that the risk of dementia for those who had quit smoking for at least 10 years was similar to that of those who never smoked.

The Risk of Second Hand Smoke

Awareness is growing regarding the risk of second hand smoke. Second hand smoke, also called passive smoking, environmental tobacco smoke or involuntary smoking, has been connected to the same general health risk factors outlined above- heart health, lung functioning, and cancer. However, research now also outlines an increased dementia risk from being around tobacco smoke through second hand smoke.

Exposure to smoke in the home, workplace and other places all were connected with increase dementia risk, and exposure in all three places was tied to the greatest risk.

Does Smokeless Tobacco Carry the Same Risk?

It is not proven yet if smokeless tobacco also increases the risk of dementia. One study outlined in the International Journal of Geriatric Psychiatry did not find any increased risk related to chewing tobacco. However, the WHO points out that it's not unreasonable to assume there is the possibility since the tobacco "contains over 2000 chemical compounds, including nicotine" (WHO 2014). Smokeless tobacco has clearly been correlated with other negative health effects, including oral cancer. 

Why Does It Matter? 3 Reasons

1. Your own health. You can potentially protect your brain by never smoking, by reducing or quitting if you do smoke, and by reducing your exposure to second hand smoke.
2. Others' health. If you smoke, realize the impact of your choice to smoke on those around you.
3. Cost and impact, both nationally and globally. Dementia is a world health concern. We currently have no effective way to treat Alzheimer's, although there are medications that have shown limited effectiveness in the short-term. Addressing smoking and exposure to second hand smoke is an area that we can exert some control over in the quest to reduce the risk of dementia, as compared to other risk factors such as age, family history or genetics which we can't control. Reducing the risk of dementia worldwide not only can save on the huge amount of money it costs to care for those with Alzheimer's, it also (and more importantly) can improve quality of life and save lives.

Resources for Quitting Smoking

About.com expert Terry Martin explains effective ways to quit smoking. Your physician can also assist you, as well as other organizations such as the American Cancer Society.

<sub>Sources:
Alzheimer's Disease International. July 9, 2014. Smoking increases risk of dementia. http://www.alz.co.uk/news/smoking-increases-risk-of-dementia

Action on Smoking and Health Scotland. May 2013. Smoking and Dementia.  http://www.ashscotland.org.uk/media/5680/dementia.pdf

International Journal of Geriatric Psychiatry. 2011 Nov;26(11):1177-85.Tobacco use and dementia: evidence from the 1066 dementia population-based surveys in Latin America, China and India. http://www.ncbi.nlm.nih.gov/pubmed/21308786

Occupational and Environmental Medicine. 2013;70:63-69. Association between environmental tobacco smoke exposure and dementia syndromes. http://oem.bmj.com/content/70/1/63.full

World Health Organization. June 2014. Tobacco Use and Dementia. http://apps.who.int/iris/bitstream/10665/128041/1/WHO_NMH_PND_CIC_TKS_14.1_eng.pdf</sub>