Posts Tagged ‘Risk Reduction’

Most Published Research Findings Are False

October 5, 2014

The title is part of the title of the epidemiologist Ioannidis’s landmark article “Why Most Published Research Findings are False” (PLOS Medicine, 2, 3124. Doi:101371/journal pmed, 0020124, 2005). Subsequent research has confirmed his conclusion. Many articles followed (see the AAA Tranche of Subprime Science (Gelman and Laken, 2014). The problem hit the popular press with the October 19th cover of the Economist broadcasting HOW SCIENCE GOES GOES WRONG.

Given the ramifications of this conclusion it is remarkable that this problem has not received much wider attention. So the healthymemory blog is standing up to do its part. The reasons for science going wrong are technical, dealing with the misuse of statistical methodology, as well as economic and political. The Economist does a fairly good job in explaining the problem for the layperson. This blog post will provide some examples and try to offer some advice.

As Ioannidis’s is an epidemiologist his critique centered on the medical literature although the ramifications of his article extend far beyond epidemiology. Most importantly the findings deal with our medical care. Readers should be somewhat aware of this as to the frequent contradictory findings regarding what is good or bad for us. Let us begin with the example of medical screening. The 5-year survival rate is one type of information that is given to promote the benefits of screening. This rate is defined as the ratio of the number of patients diagnosed with cancer still alive five years after the diagnosis divided by the number of patients diagnosed with cancer. So this rate is defined by a cancer diagnosis and leads to the conclusion that screening is saving lives. If lives are indeed being saved should it not be seen in mortality rates? A mortality rate is not defined by a cancer diagnosis. The formula for the annual mortality rate is the ratio of the number of people who die from cancer in one year divided by the total number of people in the group. It is not clear what is going on here, but if screening were indeed saving lives then it should be reflected in the mortality rate. When regarded in this light, the 5-year survival rate is a bit like a self-licking ice cream cone. Some ways of presenting the benefits of treatment are much more impressive than others. To learn more about this see the healthymemory blog posts “Interpreting Medical Statistics: Risk Reduction”, and “Health Statistics.”

To take a specific example, consider the Prostate Specific Antigen Test given to screen for prostate cancer. At one time this was regarded as being almost compulsory for males over a certain age. Now it is recommended only for males in a high risk group and, even then, only after consulting with their physician. You might ask what are the risks in screening. Apart from the costs, discomfort, and convenience, there are the side effects. In the case of prostate surgery they could be incontinence and/or impotence.

Research has also shown that many doctors do not understand how to communicate accurate medical statistics to their patients. A study reported by Gerd Gergenzer and his colleagues, “Helping Doctors and Patients Make Sense of Health Statistics” (Psychological Science in the Public Interest Vol 8_Number2, 2008) showed that few gynecologists understood positive mammograms. First lf all, the gynecologists were given the following accurate information about the women patients.

The probability that a woman has breast cancer is 1% (prevalence).

If the woman has breast cancer, the probability that she will test positive is 90%.

If a woman does not have breast cancer, the probability that she nevertheless tests positive is 90% (sensitivity).

If a woman does not have breast cancer, the probability that she nevertheless tests positive is 9% (false positive rate).

Then the doctors were told that a woman tested positive and that she wanted to know whether she has breast cancer for sure, or what here chances are. The doctors were then given the following choices from which to choose.

A. The probability that she has breast cancer is about 81%.

B. Out of 10 women with a positive mammogram, about 9 have breast cancer.

C. Out of 10 women with a positive mammogram, about 1 has breast cancer.

D. The probability that she has breast cancer is about 1%.

41% responded to option B.

13% chose option A.

21% chose option C.

19% chose option D.

Option C is the correct response.

This is based on Bayes formula for conditional probabilities. A good way of computing this is to use natural frequencies.

Consider 1,000 women.

10 are expected to have breast cancer and the remaining 990 to be free of breast cancer.

Of the 10 with breast cancer 9 should test positive and 1 negative. Of the remaining 990, 89 should test positive and 901 should test negative.

Then we divide the number having breast cancer, 9, divided by the number testing positive (89). The closest multiple choice option being C.

So what does a prospective patient do when the majority of the medical literature is wrong. First of all, do not forget the option of doing nothing. Get multiple opinions regarding your problem. And do your own research. Take all of this into consideration along with your personal values and make a decision, remembering that doing nothing remains an option.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

A Few Words of Caution to My Fellow Baby Boomers

September 14, 2011

Although I enjoy writing the Healthymemory Blog, I am usually disappointed when I view the number of visits to what I regard as important posts. For example, the preceding posts on Alzheimer’s has not drawn the number of readers that I think these posts deserved. As a psychologist, I understand why these posts are not popular, but I am disappointed nevertheless. People are optimists, so they avoid unpleasant topics. Consider the situation in which we find ourselves. Issues regarding the environment, energy, and the national debt are ignored. People blame politicians, but we should not forget that it is these same people who elected these politicians. Politicians pander to voters by glossing over these issues and being optimistic; voters then vote for them.

Alzheimer’s is not a pleasant topic. The prospect of spending our golden years being unable to recall our past, where we are living, and barely remembering who we are. The Myth of Alzheimer’s is written by one of the foremost experts on Alzheimer’s. He warns us that a magic pill or cure is unlikely to be found, but he provides us with activities that can reduce the risk of Alzheimer’s. These posts should be of interest to a large number of baby boomers. Even if you are engaging in these risk reduction activities, you probably know fellow baby boomers who are not. Why not sent these posts to those people? And please keep reading the Healthymemory Blog so I can try to keep you up to date.

The Healthymemory Blog is dedicated to these activities. There are many from which to choose. It is important to choose activities that are enjoyable to do. In many ways these activities are similar to physical activity. Sometime I do not feel like going on a bike ride, but after doing so I feel exhilirated and am very glad that I went. I think you will find a similar result for some of the cognitive exercises presented in this blog.

A Call to Us Baby Boomers

September 11, 2011

Dr. Whitehouse is one of us; he is a Baby Boomer. In The Myth of Alzheimer’s he issues a call to action for us Baby Boomers.1 As an extra incentive, he states that studies have shown that engaging in politics and keeping apprised of world events may be protective against cognitive loss.

He recommends that we encourage our local politicians to make life-span aging a priority issue. To argue for a more equitable distribution between funding for the “cure” and for “care.’ Currently most of the funding goes for the search for a cure, and in Dr. Whitehouse’s informed opinion, a cure is a long way off if one is ever found. Federal and state labor policies should help expand the pool of front-line caregivers. Youth apprenticeship programs can be created in nursing homes and assisted-living facilities in which high school students can experience hands-on learning in the workplace in conjunction with classroom instruction and to have mentored on-the-job learning in an eldercare setting. These programs can provide up-and-coming workers with the skills and competencies they will need to care for the growing number of elders in our society and provide them with the knowledge, insight, and real-world experience they will need to take care of us in the future.

He also recommends that we e-mail the leaders of our local Alzheimer’s disease chapters and express the belief that money raised for AD should be invested in care and prevention, and not just in the race for a cure that might never be forthcoming. Investing in caregiving creates a compassionate infrastructure in our communities that can last for generations. Investing in prevention allows more of us living longer with clearer minds. Children are included to ensure that they are provided a good start in their development.

We need to think about the communities of the future that will emerge to care for our elderly. Creative living arrangements such as co-ops for the elderly, inter-generational living spaces, environmentally sound assisted-living facilities that promote cognitive stimulation and inclusion in community need serious consideration. The following is a direct quote, “I am not sure we want or can afford too much institutional care for the frail elderly. If we can break down the barriers between those with dementing conditions and the healthy, and the young and other old, perhaps we can create living arrangements where people help each other across the cognitive and ageing divides. Cooperative group arrangements supported by architectural and environmental design may allow groups of mutually halping and helpful people to survive and thrive through cooperation arrangements. We are entering a challenging era as a human species. But humans are the most adaptable beings on the planet and I hope that we can rise to the challenges of the twenty-first century.2

We Baby Boomers can considered ourselves “called.”

1Whitehouse, P.J., & George, D. (2008). The Myth of Alzheimer’s. New York: St. Martin’s Press.

2Pages 277-278.

Alzheimer’s and Transactive Memory

September 7, 2011

According to the authors of The Myth of Alzheimer’s,technology and social interaction play an important role in mitigating its risk.1 Readers of the Healthymemory Blog should know that transactive memory includes the information stored in technological devices and in our fellow human beings. Hence transactive memory plays an important role in reducing the risk of Alzheimer’s. Technology ranges from the simple book to the vast area of cyberspace. Dr. Whitehouse jokingly refers to the book as a multi-neurotransmitter lexical enhancement device. Both giving and receiving information from our fellow human beings is a healthy means of social interaction.

The remainder of this blog post lists online resources provided in The Myth of Alzheimer’s.

www.eldercare.gov provides information on community organizations offering programs that stimulate, thought, discussion, and personal connections.

www.themythofalzheimers.com is an online community that shares stories of dementia. The hope is that it will foster acknowledgment of the complexity and multiplicity of the many narratives of dementia and the stories of individual lives which make them up and that this will diminish the tyranny of dementia.

www.storycoprs.net records the life histories of elders and stores them in the Library of Congress.

www.duplexplanet.com is a site designed to portray the stories of elders who are in decline.

www.memorybridge.com is the site of an organization with a mission to foster intergenerational communication and facilitate relationships between younger persons and people with dementia

www.storycenter.org is the website of a nonprofit organization that assists young people and older adults in using tools of digital media to craft, record, share, and value stories of individuals and communities in ways that improve all our lives

www.elderssharethearts.org is a web site that affirms the role of elders as bearers of history and culture by using the power of the arts to transmit stories and life experiences throughout communities

www.alz.org is the website of the Alzheimer’s Association. There is a network of local chapters that provide education and support for people diagnosed with AD, their families, and caregivers. Chapters offer referrals to local resources and services, and sponsor support groups and educational programs. The site also offers online and print publications

http://adcs.ucsd.edu is the website of the Alzheimer’s Disease Cooperative Study (ADCS) which is the result of a cooperative agreement between the National Institute of Aging and the University of California at San Diego to advance the research in the development of drugs to treat AD

www.nia.nih.gov/alzheimers is the website of the Alzheimer’s Disease Education and Referral (ADEAR) Center. It provides information on AD, caregiving, fact sheets and reports on research findings, a database of clinical trials, reading lists, and the Progress Report on Alzheimer’s Disease. It also provides referrals to local AD resources

www.caps4caregivers.org is the website for the Children of Aging Parents, a nonprofit organization that provides information and referrals for nursing homes, retirement communities, elder-law attorneys, adult-day-care centers, and state and county agencies. It also provides fact sheets on various topics, a bi-monthly newsletter, conferences and workshops, support group referrals and a speaker’s bureau

www.caregiver.org is the website for the Family Caregiver Alliance (FCA), a non-profit organizatin that offers support services for those caring for adults with AD, stroke, traumatic brain injuries, and other cognitive disorders. They also publish and Information Clearninghouse for FCA publications

www.nhpco.org is the website for the National Hospice and Palliative Care Organization (NHPCO), a nonprofit organization working to enhance the quality of life for individuals who are terminally ill and advocating for people in the final stage of life. They provide information and referral to local hospice services. The provide information on many topics including how to evaluate hospice services

www.nia.nih.gov is the website for the governments lead agency for research on AD. It offers information on health and aging, including an Age Page series, and the NIA Exercise Kit, which countains and eighty page exercise guide

www.nlm.nih.gov is the website for the National Library of Medicine, the world’s largest medicl library with six million items (and growing), including books, journals, technical reports, manuscripts, microfilms, photographs, and images. A large searchable health informationo database of biomedical journals called MEDLINE/PubMed is accessible via the internet. A service called MEDLINEplus links the public to general information about AD and caregiving, plus many other sources of consumer health information. A searchable clinical trials database is located at

http://clinicaltrials.gov

www.wellspouse.org is the website of the Well Spouse Foundation, a nonprofit organizatin providing support to spouses and partners of the chronically ill and/or disabled. It maintains support groups, publishes a bimonthly newsletter, and helps organize letter writing program to help members deal with the effects of isolation.

1Whitehouse, P.J., & George, D. (2008). The Myth of Alzheimer’s. New York: St. Martin’s Press.

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

What Can an Individual Do About Alzheimer’s?

September 4, 2011

According to the authors of They Myth of Alzheimer’s1, Alzheimer’s is not a disease but rather a conglomeration of debilitating effects that can occur during aging. They offer a prescription for successful aging across the life span. This blog post cannot do their prescription justice, but can only hit the main points.

They go into a good deal of detail about diet. Perhaps the best way to summarize their recommendations is to say what is good for the heart is good for the brain. So dietary recommendations for the heart also pertain to the brain. The same can be said for exercise. Exercise benefits both the heart and the brain.

Keeping stress to a minimum is another recommendation. Of course, stress is a part of modern life, so it is real and needs to be addressed. Physical exercise reduces stress. Walking, particularly in nature, is beneficial (see the Healthymemory Blog posts “Taking Advantage of Nature to Build a Healthy Memory,” “Restoring Attentional Resources,” and “More on Restoring Attentional Resources”). Yoga and Tai Chi are helpful, as are most types of meditation (See Healthymemory Blog posts, “Change Your Brain by Transforming Your Mind,” “Does Meditation Promote a Healthy Memory?” “Costly Gadgets or Software Are Not Required for a Healthy Memory,” “The Relaxation Response,”, and “Intensive Meditation Training Increases the Ability to Sustain Attention.” ). Avoiding individuals who are annoying or argumentative can also be helpful in reducing stress.

Remember that autopsies of people who showed no indication of cognitive decline revealed the same amyloid plaques and neurofibrillary tangles that would confirm a diagnosis of Alzheimer’s. The most common explanation for these individuals is that they had built up cognitive reserves during their lifetime. The brain can use this reserve capacity to respond to damage that might occur from aging. These are the possible mechanisms offered by the authors.

“Building a higher synaptic volume of connections between neurons

Increasing cerebral blood flow

Developing resistance to the neurotoxic effects of excess levels of hormones like cortisol and other glucocorticoids

Promoting resistance against the depletion of neurotransmitters such as acetylcholine and dopamine, which occur with age

Recruiting other brain regions to perform tasks

Increasing cerebral flow and metabolism and conferring greater resistance to the neurotoxic effects of environmental toxins”2

The obvious question is how to accomplish this. Formal education is one answer. The higher the level of education, the greater the resistance to Alzheimer’s. Fortunately, returning to school is not required. Consider the following list of helpful activities: learning a new language, learning to play an instrument, playing board and card games, engaging in intellectually stimulating conversations, reading intellectually challenging books, picking up a new skill, keeping a notebook, or starting an online blog. This list is by no means exhaustive, but you should get the idea.

Building and maintaining social relationships is also beneficial to a healthy mind. The authors provide the following list of psychosocial benefits:

“Availability of emotional support

A source of information, guidance, and advice, diversion from the stresses of life and the day-to-day travails of aging

Self-esteem

A sense of coherence, purpose, usefulness, and meaning

An increased propensity to take care of yourself and seek out professionl help

A sense of intimacy and belonging

A belief in something beyond oneself”3

Depending on the job and profession, staying employed can also be beneficial. Research has found that countries with lower retirement ages also have lower ages for the onset of dementia (See the following Healthymemory Blog Posts, “Could the AARP Be Telling Us Not to Retire,” “Passing 65,” “Can Early Retirement Lead to Memory Decline,” and “Aging and Productivity.”). Retirement is not necessarily bad, provided that post-retirement activities provide the same mental and social stimulation that was provided in the workplace.

The importance of an optimistic or positive outlook is also important (See the Healthymemory Blog Post, “Positive Psychology”).

In short, the selection of the appropriate activities you pursue during your lifetime is the best means of reducing the risk of dementia. And you are never to old to start.

1Whitehouse, P.J., & George, D. (2008). The Myth of Alzheimer’s. New York: St. Martin’s Press.

2Pages 244-245.

3Pages 252-253.

Four Ways to Present Risk Reduction

May 27, 2010

This blog posting is taken largely from the chapter, “Breast Cancer Screening,” which comes from the book, Calculated Risks: How to Know When Numbers Deceive You by Gerd Gigerenzer. I highly recommend this book. It provides important insights into risks and how they can be misinterpreted. This blog posting takes no position on screening. Its objective is to provide an accurate understanding of risks. The four ways of presenting risk reduction are not specific to breast cancer and are applicable to risk reduction in general.

Relative Risk Reduction. This is the most common means of presenting risk reduction, but the question is relative to what. The question is relative to what. Most people do not ask this question and misinterpret the statistic. Many believe that of 100 people participating in the screening that the lives of 25 will be saved. Here is the correct interpretation. Consider two groups of people, 1,000 who participated in screening and 1,000 who did not. Say within ten years (and this time period needs to be specified) 4 people in the first group and 3 in the second group died. This decrease from 4 to 3 is a relative risk reduction of 25%.

Absolute Risk Reduction. Consider the same numbers as in the preceding paragraph. The absolute risk reduction if 4 minus 3, that is 1 out of 1.000, or 01.%. In other words, if 1,000 participate in screening for 10 years, one life will be saved.

Number Needed to Treat. Again, we are considering the same data, but reporting it in a different manner. This statistic is the number needed to treat, or screen in this case, in order to save a life. The smaller the number needed, the more effective the treatment or screening. In this case the number is 1,000 because 1,000 women need to be screened to save a life.

Increase in Life Expectancy. This is the true bottom line statistic. This is the benefit expressed as an increase in life expectancy. For example, women who participate in screening from the age of 50 to 69 increase their life expectancy by an average of 12 days. Rarely, does one find benefits expressed in this manner. When news arrive that treatment x is beneficial or that lifestyle change b is beneficial, the conclusion is based on tests of statistical significance. The actual benefits can be small (in addition to future studies either failing to replicate or contradicting the study). The risk reduction statistics here are much more beneficial. Unfortunately the most popular of these, relative risk reduction, is usually presented without sufficient information for its accurate interpretation with the resulting interpretation being overly optimistic. For myself, give me the increase in life expectancy. Before I take screening test x, or engage in behavioral change b, I want to have an estimate of how many days it buys me.