Massive Review Spanning 27 Years of Research
These Harvard researchers reviewed data from seven large studies, with almost 50,000 subjects. In all the studies, men and women aged 65 and older were followed for at least 15 years. The researchers studied the participants’ health via in-person exams, genetic data, brain scans and risk factors for cardiovascular disease. Additionally, there was a separate assessment for Alzheimer’s disease. The study found that the incidence of this particular form of dementia has steadily fallen across the U.S. and Europe, at a steep rate of 16 percent per decade over the last 27 years. Dr. Albert Hofman, the lead author of the study, put these findings into perspective: “In 1995, a 75-year-old man had about a 25 percent chance of developing dementia in his remaining lifetime. Now that man’s chance declined to 18 percent.” What’s more, the study found the incidence of dementia at every age has also declined over the past quarter-century. In fact, the risk of developing dementia over a lifetime is currently 13 percent lower than the 2010 rate. The Harvard researchers published their study findings in the journal Neurology.1So How Come So Many People Have Dementia?
At first blush, the findings may seem to be at odds with the reality that there are now more dementia patients than ever before. However, that’s because there are higher numbers of older people in the population now than ever before. The number of elderly has soared; the percentage that will get dementia has gone down. Something else that’s interesting, researchers did not see a decline in dementia rates in Asia, South America, Japan, China or Africa. The Harvard researchers believe that continued increases in those countries could be attributed to certain risk factors for dementia, like smoking. Turns out, managing risk factors might be the secret to success in lowering rates of dementia.Why Did the U.S. and Europe Fare Better?
Frequent readers of this site won’t be surprised by some of the Harvard researchers’ theories as to why people in the U.S. and Europe are better at staving off dementia. We’ve discussed them here often. At the top of their list is improved control of cardiovascular risk factors, such as blood pressure and cholesterol, in the U.S. and Europe. Scientists have found that most dementia patients have other brain abnormalities, including damage to blood vessels, which is often a result of high blood pressure. Dr. Hofman also notes that better education in the past three decades may be a reason for the declining rates. Some experts believe that education provides the brain with a protective effect, boosting the capacity. As we’ve noted in previous articles, challenging the brain increases its capacity, so you can afford to lose more of it in old age and still have enough left to function pretty well. The concept is called “cognitive reserve.”Good News: You Can Reduce Your Alzheimer’s Risk by 40 Percent
Dr. John Morris, director of the Center for Aging at Washington University, offers his insight into the Harvard research in an article in The New York Times, calling the new data “hopeful.”2 “It is such a strong study and such a powerful message,” he states. “It suggests that the risk is modifiable.” Other leading scientists agree. They presented additional research on modifiable risk factors for dementia at the 2020 Alzheimer’s Association International Conference (AAIC).3 These researchers reported that a whopping 40 percent of dementia cases might be prevented or delayed by modifying 12 risk factors. The list of risk factors, and what you can do about them, include:- Smoking— don’t do it
- Physical inactivity—take up regular exercise
- High blood pressure—lower your blood pressure with lifestyle changes and/or medication
- Obesity—lose weight
- Social isolation—stay engaged with family, friends, your community
- Depression—seek help from a mental health professional when needed
- Diabetes—balance your blood sugar with lifestyle changes or medication
- Hearing loss—get help for age-related hearing loss early on
- Not completing high school—you can get your GED at any age
