The number of people with Alzheimer's disease will nearly triple in the next 40 years, a new report predicts. The study estimates that there will be 13.8 million people with the disease by 2050. Nearly 5 million Americans are affected now. The U.S. government and the Alzheimer's Association funded the study. A future study will estimate the health care costs. The Alzheimer's Association predicts they will rise to more than $2 trillion. The new study is based on information from 10,802 Chicago residents. All were ages 65 or older when the study began. Researchers kept track of them up to 18 years. They were assessed for dementia every 3 years. The estimates also include data from the 2010 census. Much of the increase in Alzheimer's is tied to the aging of the huge baby boomer generation. The census estimated that the population of people 65 and older will more than double by 2050. All of these estimates assume that no medical breakthroughs will occur. So far, there is no effective way to prevent or treat Alzheimer's disease. The journal Neurology published the study February 6. USA Today and HealthDay News wrote about it.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

It's hard to overestimate the impact of Alzheimer's disease.

For someone with the disease, for family and friends, and for society, Alzheimer's disease is nothing short of a tragedy. We don't know what causes it. But we do know the effects. Alzheimer's gradually but relentlessly destroys people's ability to think and function on their own.

Despite decades of research, we have no effective way to prevent this disease. And, once it begins, we have no effective treatments to reverse the brain damage. Medicines approved to treat Alzheimer's disease may have a modest impact on slowing down the disease. But the average person with the disease may have a hard time knowing whether these medicines are helping at all.

Now comes word that new cases of Alzheimer's disease are predicted to increase dramatically in the United States. The medical journal Neurology published the new estimates. Researchers are predicting that by 2050 Alzheimer's disease will:

• Affect 3 times as many people as it does now
• Affect 13.8 million people (compared with 4.7 million in 2010)
• Affect 7 million people over age 85 (compared with 1.8 million in 2010)

These numbers are alarming, to say the least. They mean a vast expansion of the devastation and heartache so well known to people who have the disease and their families. Beyond that personal impact, the estimated cost of caring for people with this disease is $100 billion or more each year. Of course, costs will rise even higher if the disease becomes more common.

The discovery of an effective prevention or treatment could reduce these numbers. But the authors point out that any new treatment probably would not have an impact right away. So, unless the estimates in this new report are wrong, the hard truth is that we'd better gear up for a big increase in Alzheimer's disease.

What Changes Can I Make Now?

There are no reliable ways known to prevent Alzheimer's disease. However, you can take measures to increase your chances of maintaining good brain function as you age.

Here's what you can do:

• Exercise regularly. Past research suggests that physically active people are 50% less likely to develop Alzheimer's disease than people who get little exercise.
• Change your diet. A diet that’s high in fiber, fruits, vegetables and omega-3 fatty acids has been linked to a lower risk of Alzheimer's disease.
• Maintain a healthy blood pressure. This may require loss of excess weight, a low-salt diet and, in many cases, medicines.
• Keep your blood lipids in a good range. This includes total, LDL and HDL cholesterol levels. Weight loss and dietary changes can help. However, you may need medicines, too.
• Avoid excess weight. Check your body mass index. If it's high, talk to your doctor about how to reduce it. Weight loss programs and increased exercise are usually the first steps to take. But sometimes medicines or surgery are recommended.
• Don't smoke. If you smoke, commit to giving up the habit. While some can quit on their own, many smokers need help. Your doctor may recommend a structured smoking cessation program, medicines or both.
• Keep your mind active. Some research has found that dementia is less common among those with a busy social life and hobbies. Mentally challenging activities, such as board games or crossword puzzles, are often recommended. However, their overall benefit is uncertain.

Keep in mind that not everyone with memory problems or other problems with brain function has Alzheimer's disease or dementia. For example, some people thought to have dementia turn out to have depression, thyroid disease or side effects from medicines. These are important to consider because they can be reversed with treatment.

What Can I Expect Looking to the Future?

It's vital that researchers keep track of Alzheimer's disease rates. If these new estimates are accurate, much work is ahead. Health care professionals, insurers and public health officials will need to plan for the care and added resources required by the rising numbers of people with this dreadful disease.

You can also expect to hear much more about research to find the cause (or causes) of the disease. The discovery of a cause would be a major breakthrough that could lead to more effective preventive measures and treatments.