WELL-DAYS: What they Mean. How they are Determined
Abstract: Well-Days provide the number of days (or years) remaining to life expectancy less subtractions from these days for the loss in quality of life due to suffering major diseases. Good health habits extend life and in addition enhance life somewhat further by reducing the suffering disease. The Well-Days measure is believed to provide today's most realistic valuation of the most likely value of reducing risk of disease via better health habits.
The Ultimate Goal for better Health Habits: The obtaining of both a longer and better life is the key goal of the health-interested person. Academic researchers are entranced by ideas such as diet deprivation and gene modification that could extend life. A hundred different pills that supposedly will extend life are promoted. But somehow lost in this academic research and pill promotion is one very simple reality: Obtaining a longer and better life requires first and foremost the avoidance of the major diseases that now terminate it. If we fail to slow cancer and heart disease that now terminate most US lives nothing else is going to extend life very much. And extending life can be of little benefit if it is accompanied by the other diseases such as arthritis, diabetes, macular degeneration and dementia that can seriously diminish its quality.
A key goal of Life Ahead is to identify and teach from all pertinent available research how to Reduce the Risk of the Major Diseases that now both terminate life and reduce its quality. Reducing the risk of these diseases by better health habits not only will extend life, but can make those extended years far better. The new Well-Days concept quantifies both the likely length of life, but the disease free quality of life that can be obtained from better health habits.
The Problem of Understanding Health Research Results: Communicating the results of Health Research to lay people has been and continues to difficult.. A research study usually reports to some medical journal two key things. First is a statistical ratio of the disease or death of a population having some habit or factor vs. that of a similar population having a different habit or factor. Second is the statistical accuracy limits of this factor. As a typical example: Population "A" that exercises has 40% less heart disease than does similar population "B" that does not exercise. And second, reported to the journal but rarely mentioned to the public is the usual wide accuracy limits of a health research ratio as "This average risk of 0.75 is subject of 5% to 95% limits of accuracy from 0.25 to 1.00. The media reports the above average percent value as an implied accurate number - and not as "A value probably somewhere between 25% and 100%. If the value is significant to 95% it is reported "We found a significant effect. If the value is significant to less than 95%, as say 90%, its is stated "We found no effect." This dogma creates continually confusions of statistics that have little meaning. And with accuracy of range of 50% as is typical from health research, it becomes inevitable the a sizeable fraction of studies - as about 1/3 of them - will disagree. We must have multiple studies to obtain a useful value of risk.
Further, a risk value such as the above percentage does not communicate anything very meaningful to a health-interested person. The above example suggests it is "Good" to exercise. But how good? Is it really worth while? A risk ratio as "Risk was reduced in half" can communicate something very misleading. An average US man of age 50 has a 1 in 45 chance of dying of heart disease in the next ten years. For a man of age 40 that risk in the next ten years is only one in 155 times. This result suggests that by "exercising" he would change these risks to 1 in 90 times at age 40 and 1 in 310 times at age 50. For woman of age 40 that risk would change from 1 in 1400 to 1 in 850. A quoting of these more realistic odds would fail to motivate many people to exercise. It probably would even not persuade the news media to publish the study result.
Risk ratios from Health Research for different diseases can be even less meaningful. Heart disease is a major risk of early death. The risks of lung cancer death for an average US 50 year old non smoker in the next ten years would be only 1 in 550. A 40% reduction in risk would change this to about 1 in 900. A given risk ratio also will have vastly different meaning for people having good health habits than for those having average or poor health habits. A risk at younger and older ages can be far different from the value that usually is measured for people of about age 50. And we are constantly confused by such ratios that provide little guidance about the really important things we need to do. We learn only that doing certain things are "Good" or "Bad." We obtain little perspective from research studies per se about what is really important and what is trivia.
A more useful method for valuing health habits is their effect on overall risk of death during life. Many of the earlier health risk appraisals cited effect of factors as smoking and high blood pressure on risk of death. A problem here is that people just do not like to accept death as a risk. This is something they prefer not to think about. The idea of multiple risks of death for different actions can be confusing, and this has been widely verified from results of health appraisals provided to individuals that develop such risks. .
Another and more appropriate method for valuing a health risk is to estimating its effect on life expectancy. The statement that the above "exercise" could increase life expectancy by say two years does convey more useful meaning. But there are at least three major problems with life expectancy. First, many people are unimpressed with the idea of life expectancy to a somewhat more advanced age. They visualize that a few more years of life simply means living those years with infirmities and/or in nursing home as do many people of those advanced ages. Second and for useful meaning, life expectancy requires the exercise or other habit change to be maintained continuously over life. And finally translating the heart risk ratio that is usually measured on populations of average age 50 to their effect on life expectancy requires the usually unavailable technology of life-cycle modeling about how risk ratios change with age, and how effects of different diseases interact over life. These effects from a seriously developed life-clyce model become very complex. Most quoted values for "Life expectancy" are based on crude statistical extrapolations that can be seriously flawed.
The Well-Days Method: Well-Days provides what may be today's best solution of the problem of understanding Health Research Results. We are given the great gift of life at birth. The ultimate value of the gift of life also depends on what we do with those available days. But the starting point of that gift of life must the those days that we are Physically Well. Days Not Well can be defined first as those alive but Not Well enough to contribute positively to the enjoyment of life. Some of those Not Well days are those in which we are ill land either in bed or in serious pain. Or when we are recovering from an operation or illness and perhaps also diminishing the quality of life of family members caring for us.
A more important source of Not Well days is those that still provide some positive contribution to life, but are diminished in quality by major disease. Examples are the days diminished by the facing of a major heart operation, and the perhaps months of recovering from it; The days diminished by the continual pain of arthritis; The days seriously diminished by dementia; The days diminished by the disability of macular degeneration that produces a gradual and perhaps permanent loss of vision; The days diminished by the progress of cancer; or the potentially dreadful disability of a stroke.
Today's research now shows that life style habits can have an important effect on every one of these disabling diseases. Better habits can either prevent these diseases from ever occurring, or delay their time of onset. This not only prolongs our life, but makes those days of life better.
The Well-Days method used in Life Ahead computes first the number of days and years remaining to life expectancy for a population having the factors and habits of either an average person or a user having any other combination of lifestyle habits and diet. It then subtracts from these total days a quality debit for the fraction of this specific population that will suffer each disease during life. Although Life Ahead produces results on an entire population of individuals, this same result identifies a risk for an individual. The subtractions now made via Life Ahead are very conservative and approximate, and in total subtract only a rather small number of days and years from life expectancy. But they do provide what is believed to be a more accurate and useful valuation of the lifetime benefit or debit of exercise, diet, and other health habits than the usual information that is published today.
Life Ahead's Well-Days should provide today's most meaningful measure of the value of changing health habits. It presents results as a positive value that has specific meaning for a population of individuals. Although it is impossible to forecast the lifetime risks of any individual, these same population values of risk provide a most likely risk for an individual. And present valuations should be continually improved as more research is published and analyzed.
How Life Ahead Computes Well-Days: The first step in computing Well-Days is that of computing life expectancy of a population. This method is discussed in the Web Site paper Life Ahead Basis and Method In brief, Life Ahead shows for the Demo Program or for any user having average US habits the actual recent life expectancy of a non-smoking man or woman. The actual US vital statistics include a fraction of the population that has and still smokes cigarettes that is different at every age. The Life Ahead model subtracts out the confusion caused by the inclusion of this smoking population. Thus Life Ahead values for risk of disease and death at age for non-smokers are slightly lower and life expectancy is slightly higher than values of average NIH statistics. Adjusting for the smoking difference, the Life Ahead values of life expectancy from any age mirror those in the NIH within one year or less to age 100. Life ahead values for ages above 100 are estimated from some death rates found for very old persons.
The base death rate file used in Life Ahead includes rates at age from 1 to 110 for each of 17 included causes of death. Overall death rates are recomputed for each year of life to life expectancy. Any or all of these rates optionally can be modified from average rates starting at any age of life based on the differences of up to 75 different user habits plus an entered diet. The differences in most of these risks for different user habits and factors are based on results of all useful research found published.
The second step in the computation of likely Well-Days are the subtractions assigned to those in the population that will be contracting up to each of the 17 most important US disabling diseases. Most of these are the key US causes of death. Some individuals in the population and especially those with poor health habits will experience more than one of these diseases during life. Life Ahead computes a risk of each of disease and death at each age of life, and accumulates these risks up to life expectancy from present age. The proportion of individuals that will have contracted each of these diseases and remain alive are then then computed to life expectancy.
The subtractions of "Not Well" days or days of diminished quality for those suffering the various diseases are very approximate. But they are conservative and in aggregate should provide a more useful measure of the value of improving health habits that of only computing risk of disease and death. The subtractions made at this writing follow, and these may be modified as better information on this is obtained. The subtractions initiate with a approximate estimate of the usual duration of a major disease or survival time during life. These durations are multiplied first by the actual risk of each disease in the population, and second by an arbitrary factor that identifies the quality of life via the fraction of potential well days lost as Not Well days due to the suffering of these diseases. A maximum value for the duration estimate is from present age to life expectancy.
A full estimate of Well-Days should include the loss in quality of life of the usual family caregivers whose life also is diminished by the required care. As example the quality of life of a a spouse or relative may be substantially diminished by having to care for a relative with dementia as alzheimers, that suffers a disabling stroke, or who is blind from macular degeneration. No recognition of this is now given in Life Ahead. Although this estimating method could be much refined, some tests suggested that such refinements probably would not change the Well-Days estimates significantly.
For Heart Disease: A subtraction of just 10% is made now for the population suffering some form of heart disease. Duration is estimated as 20 years or less if time from present age to death is less than this. There is serious loss of quality days recovering from heart operation, or to those that suffer angina. Some forms of heart disease as congestive heart failure are seriously disabling But a majority of those suffering a heart attack that recover from it are able now to do most of the things needed for a quality and reasonably long life.
For Stroke: A subtraction of 30%. Stroke can be a major disabling disease. Duration is 7 years. Patients can be confined to a wheel chair, or can walk only with assistance. They can be deprived of speech.
For Lung Cancer: A subtraction of 30%. Average duration or survival is only 0.6 year. This often is a near death sentence as few sufferers survive more than a year or two. But because usual time between disease diagnosis and death is not long, the total subtraction for this disease is usually small.
For Female Breast Cancer: A subtraction of 20%. Duration is 20 years. Breast cancer is a serious trauma for a women and may involve mastectomy. But survival usually is two decades and most women can lead near normal lives during this period.
For Prostate Cancer: A subtraction of 15%. Duration is estimated at 8 years. Prostate cancer that often is found in time can be treated and men usually will not be seriously disabled by it. But as a minimum men will endure radiation or other treatments and suffer the trauma of having cancer that always can progress elsewhere. Prostate cancer can be disabling and cause serious suffering if it does progress.
For Female Genital Cancer: A subtraction of 25%: Duration of 10 years. Survival time is longer for uterine cancer, but much shorter for ovary cancer. This is a devastating disease for most women that can require a hysterectomy.
For All Other Cancer: A subtraction of 20%. A duration of 10 years. The above factors for other cancer apply here
For COPD, Respiratory Disease: A subtraction of 30%: Duration of 6 years. This can be a seriously disabling disease that can require continuous oxygen administration, limits physical activity, and can require full time care.
For Diabetes: A subtraction of 20%. Duration of 10 years. The joy of eating can be seriously reduced by the need for unwelcome diet changes needed. The need for monitoring of blood sugar places sufferers in continual concern about the problem. More advanced cases can lead to loss of vision and amputations.
For Flu and Pneumonia: These diseases usually are of short duration and involve usual recovery for far longer periods of time. They can diminish Well-Days 100% during their term that in extreme cases can be fatal. But duration of disease is usual short and no subtraction for risk of this disease is now included in the program.
For Kidney Disease: A subtraction of 10%. Duration of 4 years. This can be extremely painful during occurrence, but then requires treatment. Because Life Style factors have not been verified adequately for risk of kidney diseases Life Ahead does not forecast a value for reducing risk of this disease.
Dementia: A subtraction of 35%. A duration of 5 years. Alzheimer's disease or vascular and other dementia are most serious causes of loss in Well-Days for older person's, and prevalence of these diseases had been growing rapidly. A patient proceeds from mild cognitive loss to complete loss usually over periods ranging from 3 to 10 years. Quality of life is seriously diminished during much of this period, and usually is near near zero at disease end stage. But many mid-stage patients can enjoy days and events as they occur even when no memory of these events is retained.
Osteoporosis: A subtraction of 5%. A duration of 5 years. The weakening of bones caused by this disease can cause hip and other major fractures that in most serious cases can lead to early death. Yet over much of the time this disease exists diagnosed patients can be unaware they have any problem. Thus its effect on the quality of life of most people occurs only during the time of major fractures that is relatively short vs. total duration of disease.
All Other Diseases: A subtraction of 10%. Duration of 10 years. The category includes hundreds of other life diseases that can range from trivial to seriously disabling. The inclusion of this debit is arbitrary and may be quite conservative. Because this group is not researched for effects of life style habits or diet, it does not contribute much to Life Ahead valuations.
Arthritis: A subtraction of 15%. Duration of 10 years. Arthritis involves continual pain at one or more body sites, and is identified in Life Ahead at a level that requires either hospitalization or multiple doctor treatments. Patients can be partly or seriously disabled from walking or using hands. Most patients carry on most of life's activities, but with the troubling problem of continual or near continual pain and the taking of pain mediations that often are not successful.
Macular Degeneration (AMD): A subtraction of 20%. Duration of 5 years. AMD is another disease that is sharply increasing as our population becomes older. The disease usually is slowly progressing, and gradually can close out sight in one or both eyes. Patients usually will retain some sight for years, but as sight diminishes it can became more and more difficult to read and to accomplish many of life's usual tasks. As the disease proceeds to total or near total blindness the quality of life will decline perhaps 80% or more. This assumed 20% estimates a net reduction in quality of life over the total period of disease occurrence that may be quite conservative.
Any ideas from researchers or other about these assigned values for quality of life will be welcome.