Although Dr. Ward Dean is probably best known as the Medical Editor of CERI and coauthor of a number of smart-drug books, he is also the author of "Biological Aging Measurement-Clinical Applications", a remarkable compendium of age-measurement systems from around the world. Smart Basics carries this unique book and in the following interview with Steven Fowkes of CERI, Dr. Dean introduces some of the concepts underlying biological aging markers (biomarkers).
FOWKES: What is biological age and how can it be used to evaluate aging interventions and treatments for age-related mental decline?
DEAN: Biological age is an objective assessment of a person's health status. What we are trying to do is show objectively- through clinical laboratory tests-what is readily apparent to everybody: the differences between a young and old person. Certain parameters, called biomarkers, change significantly with age. By measuring a number of them and combining them into an equation, we can determine someone's functional-or biological-age. By tracking these results from exam to exam, we can determine a biological rate of aging. A life-extension or smart-drug program which lowers this aging rate is successful. One that increases it is not.
FOWKES: Your book makes a great case for the feasibility of measuring biological age. How do you think this emerging technology will eventually affect our health or health-care delivery system?
DEAN: Ultimately, aging measurement, or functional assessment, will become a routine part of annual physical exams. Right now, when you have a physical examination, if everything is essentially normal, you're given a pat on the back by your doctor and told to come back in another year to repeat the same thing. Under these circumstances, normal examinations are essentially meaningless. However, with aging measurements we are able to determine an improvement or decrement to your health from exam to exam, from year to year. This is really the only way for life-extension experimenters to determine whether their life-extension programs are working or not.
FOWKES: One of the problems with traditional testing is the broadness of the "normal" range. Within that range, a normal test result may or may not be normal for a specific person.
DEAN: Exactly. We've found that you really have to consider each individual a case study of one. Rather than compare yourself with the entire population, it's better to compare your own results from exam to exam. So you're really comparing yourself to yourself. Even with most routine physical exams as currently done, there's really no way to easily compare your performance from one exam to another.
FOWKES: Articles come out periodically about the inaccuracies and mistakes of medical tests. How does that affect biological aging measurement?
DEAN: It's a real problem. For example, blood pressure, which is included in many age-measurement test batteries, is notoriously variable. Just walking into an unfamiliar doctor's office can cause a person's blood pressure to increase significantly. Overexertion - possibly from walking up a flight of stairs - will probably make blood pressure go up. This is a real problem with the current state of the art of aging measurement. However, as our understanding of aging increases and we find better biomarkers of aging, the measurement of biological age will become more accurate.
FOWKES: Why isn't biological aging measurement being used?
DEAN: That's a very interesting question. For years, the American gerontological community has adhered to the dogma professed by several National Institute on Aging [NIA] psychologists that biological age could not be measured. This is obviously ridiculous. For example, even a child can tell whether a person is old or young based on their appearance. Using aging measurements, we attempt to quantify various physiological, biochemical, psychological and anthropometric parameters into a single biological age which can be compared from exam to exam. Although American scientists have not done much research in the field of biological aging measurement, foreign scientists - especially in the Soviet Union, Japan, Australia, and Finland - have done extensive research in this area.
Unfortunately, there has never been a standardized set of measurements that could be used to measure biological age. Although there have been many published aging measurement studies in the scientific literature over the last 20 or 30 years, none of these studies completely described the entire test protocol or gave enough information for other scientists to replicate their work. Thus, one of my purposes in writing Biological Aging Measurement was to completely describe these tests so that scientists and life-extension experimenters could replicate the previous work of scientists, validate their tests, and even possibly develop new, simpler, cheaper and/or more accurate tests.
FOWKES: To what extent can people measure their own biological age, using technology that is readily available and inexpensive?
DEAN: They can do this fairly easily. Several tests can be performed at home. One of the best measurements is near visual acuity. This is basically a measurement of presbyopia [impaired near vision] where the lens of the eye becomes increasingly less flexible as we grow older. This is due to cross-linking of the crystalline substance in the lens, and also because the lens is encased in a capsule which becomes stiffer and stiffer as cells continue to reproduce. This aging process leads to "old-age sight," or presbyopia, which requires bifocals or reading glasses to correct.
Near-visual acuity is one of the most accurate and reproducible measurements of aging. It can be done with a yardstick and a business card. If you normally wear glasses or contact lenses, you should wear them for this test. Place the yardstick against your cheek and bring the card as close to your eye as you can without the print blurring. The minimum distance that you can see the card in perfect focus is your near vision. You can then use the figures in the book (pages 321-322) to determine your near-vision biological age.
Another excellent test is maximal oxygen uptake (VO2max). Although accurate readings of VO2max require a metabolic measurement cart, EKG electrocardiograph machine and a means of analyzing expired gasses, men can get a reasonably accurate approximation of VO2max by clocking the time it takes them to cover a mile and a half (see bottom of facing page). If it takes 12 minutes, then their VO2max is about 42.5 ml/kg, the average for a 37-year-old man.
FOWKES: What kind of professional supervision is either required or recommended for measuring biological age?
DEAN: Many of the tests will require a physician to do the testing because of clinical laboratory tests that require blood work. Other measurements, like pulmonary function, require equipment which only a physician is likely to have. It depends on what is being measured, but most general physicians would have adequate equipment to do aging measurements - or they could easily obtain the required equipment. Some medical equipment is now available to the general public.
For example, home glucose monitors can be purchased in drug stores for less than $100. Glucose tolerance (the body's ability to regulate glucose) decreases with age. This test is conducted in the morning after an overnight fast. After a baseline glucose measurement is taken, drink about 50 grams of glucose (about 12 ounces of grape juice) and test your blood glucose one and two hours later. The chart (pages 384-385) can be used to calculate your glucose-tolerance biological age.
Another simple home test is blood pressure. Sphygmomanometers (blood-pressure cuffs) and stethoscopes can also be purchased in drug stores (instructions are included). Compare your blood pressure with the charts found on page 298-301 of the book to determine your blood-pressure biological age.
FOWKES: Are professional attitudes about biological aging measurement changing?
DEAN: I think so. It seems that there's greatly increased interest in biological age measurement. The American Aging Association held a symposium in 1988 that was based on my book. It was the first time that all of the biological-age-measurement scientists from around the world were brought together at one meeting. The following year, there were two symposia on the subject that were held at the International Congress of Gerontology/Geriatrics that was held in Acapulco. A recent issue of Experimental Gerontology was devoted to the subject. I think that the two NIA scientists who claimed that aging could not be measured have now largely been discredited. I think we will see some real significant progress on biomarker research and aging measurement in the future.
FOWKES: How can we best reduce biological age?
DEAN: The best anti-aging pill that we have today is exercise because it improves so many of the best age-associated biomarkers. For example, it improves maximal oxygen uptake, pulmonary function, and lipid ratios, lowers blood pressure, and there are even studies that show that it improves eyesight.
Reprinted with kind permission of one of our our favorite publications, Smart Drug News. Each month SDN covers the latest in cognitive research, from coping with Down's syndrome and Parkinson's, to treating age-related mental impairment in normal, healthy adults-a must-read publication for anyone interested in increasing their mental faculties or fine-tuning a life extension program. For more information go to the CERI website.
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