Donald Kennedy, editor of the journal Science, calls for brain scans to be given privacy protections equal to DNA sequences.

America recently passed legislation preventing businesses from obtaining customers' DNA amid fears they could use it to discriminate against those deemed more risky. In Britain a moratorium is in place to prevent companies from accessing customers' genetic material.

Prof Kennedy told the Guardian: "There's a push to prevent genetic information being used by companies for adverse selection, and at least equal protection should be given to brain scan data."

What makes brain scans seem special is that scanning techniques may eventually provide insights into personality type, behavioral tendencies, and, when conducted in concert with appropriate environmental stimuli, they might even eventually provide insights into beliefs and memories. For instance, brain scans might eventually be usable as part of a better lie detector test. The desire to keep one's own thoughts secret is certainly a reason to place some sort of restrictions on what insurance companies can get access to. But most brain scans are made for more mundane purposes that make them little different than scans done in other parts of the body: to discover tumors, clots, leaks in arteries, and other medical problems. A blanket ban on insurance company access to brain scans is no more or less justifed than a blanket ban on insurance company access to chest scans.

Can all that much about a person's thoughts be divined from a brain scan? Razib of Gene Expression has pointed to a pretty good response to the recent report about being able to detect racism with fMRI (functional Magnetic Resonance Imaging) brain scans. In that response Carl Zimmer says that there is a lot of subjective judgement involved in interpreting brain scans and we should take such reports with a grain of salt. In time more rigorous brain scan studies linking scan results to beliefs and feelings will be done with appropriate double blind controls and larger groups of patients even as brain scanning machines become more sensitive, accurate, and cheaper to operate and interpret. The ability to use fMRI brain scans to learn more about a person's thoughts will no doubt improve with time. But is that one single application of brain scan information a reason to single out brain scan results to restrict insurance company access to those results? Couldn't insurance companies just be banned from accessing brain scan tests that are done to study beliefs and feelings?

Is there anything about brain scan results that make them in some way more logically equivalent DNA sequence information as far as insurance companies are concerned? Remember that the big problem with DNA tests is that they will eventually provide a great deal of insight about the long term risks that each person has for various diseases. Brain scans may eventually do that if they can, for instance, detect the early stages of Alzheimer's Disease decades before disease symptoms become noticable. But the same may turn out to be true of blood tests that may eventually be able to predict Alzheimer's risks and other neurological disease risks decades in advance.

The early detection of neurological diseases is part of a larger trend that is resulting from the broad advance of medical testing in general. Look at how cholesterol tests have become increasingly more refined as a single number for blood cholesterol has been broken down in the HDL, LDL, and other components and now even subtypes of HDL are being discovered while other potential risk factors such as C Reactive Protein (CRP) are being investigated. Also, scans to detect plaque build-up and artery and heart abnormalities have steadily become more accurate and useful. The sensitivity of a broad range of biological tests is going to continue to advance to make it increasingly easier to detect a large variety of diseases and disease risk factors at progressively earlier stages.

At first glance, what might seem to make DNA tests different than other types of tests - including brain scans - is that DNA tests will be able to provide an assessment of many health risks before any sort of disease process has even begun. For instance, a female baby at birth will be able to be scored for breast cancer risk before the baby has even gone thru puberty to grow breasts that can become cancerous in the first place. But DNA sequence tests are not unique in their ability to detect disease risks decades before diseases develop. For instance, there are events that happen during development that cause variations in outcomes by changing epigenetic programming in various parts of the body. Epigenetic information tests will also eventually become available. One way to respond to this is for genetic testing privacy laws could be extended to encompass epigenetic testing results as well.

But other ways to detect differences in developmental outcomes will also be developed. For instance, advanced imaging techniques may be able to measure the relative sizes and details of the shapes and activity of glands and organs. From those scans it may be possible to calculate risks for glandular disorders and organ disorders. Imaging and other sensing techniques may be able to detect heart problems decades before they become life-threatening. There does not appear to be a clear dividing line between health risks detected well in advance of disease using genetic testing and risks detected in advance using other kinds of tests.

The problem posed by advances in medical testing for insurance is not limited to DNA testing or even DNA testing plus brain scans. Costs of tests will fall, newer and less onerous tests will be introduced, and existing tests will become more sensitive even as more sophisticated and automated methods will be developed to analyse test results and use them to more accurately predict the development of future health problems. People will therefore discover more health risks at much earlier stages of their lives. This will cause those at greater risk of diseases to seek more medical insurance while those at less risk will buy less insurance. Bans on insurance company access to medical test results will not prevent this problem from developing because the high risk buyers of insurance will buy more while low risk buyers buy less. Insurance companies will have fewer healthy customers and more unhealthy customers.

Update: There is an important and beneficial way that early disease risk identification can actually improve the workings of the medical insurance market: If insurance companies are allowed to know as much about the health risks of insurance applicants as insurance applicants know about themselves then insurance companies will eventually offer policies contingent upon the applicants getting certain treatments in advance or continually in order to maintain coverage. Look at elevated cholesterol for example. It would make some sense for an insurance company to require a 50 year old with elevated cholesterol to take Lipitor and/or to go on a cholesterol lowering diet to lower cholesterol below some target point as a condition of coverage. One can even imagine a sliding scale of premiums based on cholesterol test results.

As more health risks become identifiable at early stages and as more treatments are developed to reduce specific risks the incentive for the insurance companies is going to be to require treatments as a condition of coverage. The insurance companies may require that the applicant pay for the risk-reducing treatments. Some treatments, such as cholesterol lowering drugs, may need to be taken continually for years. But in the future real "fix it" treatments will become available. For instance, a more permanent way to fix elevated cholesterol problems will be to do gene therapy to the liver so that it produces different quantities of the precursor lipoproteins that form parts of various types of blood cholesterol molecules. Basically, change the DNA programming of a liver for a high risk person to make it function more like the liver for a very low risk person.

This approach of providing incentives for risk reduction could be expanded in all sorts of ways. For instance, as various forms of medical tests become cheaper and easier to do imagine periodic testing to measure how well each person is nourished and how much stress a person is under. A person pursuing a lifestyle that causes less wear and tear on the body ought to be able to pay lower insurance premiums than a person who chooses a diet and lives under conditions that pose greater health risks.

This approach of pricing more accurately to risks has obvious precedents in other insurance markets where, for instance, insurance companies offer lower rates if fire detection and fire fighting equipment is installed and where structures are inspected and modified to be less likely to catch fire in the first place.

Update: A few recent reports illustrate how medical testing advances will allow progressively earlier identification of diseases and disease risks. First off MRI brain scans can identify those at risk of Alzheimer's Disease several years before clinical symptoms become identifiable.

Using a new technique to measure the volume of the brain, they were able to identify healthy individuals who would later develop memory impairment, a symptom associated with a high risk for future Alzheimer's disease. The study is published in the December issue of the journal Radiology.

In the small study, led by Henry Rusinek, Ph.D., Associate Professor of Radiology at NYU School of Medicine, the researchers used MRI scans and a computational formula to measure a region of the brain called the medial-temporal lobe over a period of two years. This area contains the hippocampus and the entorhinal cortex, key structures allied with learning and memory. The researchers found that each year, this region of the brain shrank considerably more in people who developed memory problems compared with people who didn't. The medial-temporal lobe holds about 30 cubic centimeters -- the equivalent of one-sixth of a cup -- of brain matter in each hemisphere of the brain.

"With our findings, we now know that the normal healthy brain undergoes a predictable shrinkage that can be used to help recognize Alzheimer's several years before clinical symptoms emerge," says Dr. Rusinek. "We believe this is the first MRI study to report these findings in healthy people, but it is only the first demonstration that extremely early diagnosis is possible, and the technique still requires additional work before it is ready for the clinic," he adds.

The technique was about 90 percent accurate, meaning that it correctly predicted cognitive decline in nine out of 10 people, and it also correctly identified 90 percent of those whose memories would remain normally for their age.

However, the study only involved 45 people; future studies need to ascertain whether the technique would be as accurate in a much larger pool of subjects. In addition, it remains to be shown whether other neurodegenerative diseases that affect the aging brain can also be accurately identified with this technique.

In another study blood pressure and C-reactive protein combine to more accurately predict stroke risk.

When levels of both blood pressure and C-reactive protein (CRP) were elevated, the risk of future heart attack and stroke increased as much as eight times, researchers report in the Nov. 25 issue of Circulation.

"What our study shows is that, at all levels of blood pressure, knowledge of CRP levels greatly improves our ability to predict which patients are at very high risk," said Dr. Paul Ridker, the director of the Center for Cardiovascular Disease Prevention at Brigham and Women's Hospital in Boston and the senior author of the study.

In yet another study Duke University Medical Center researcher Jason Allen has found evidence suggesting that nitric oxide metabolite levels are inversely associated cardiovascular disease risks.

"First, it appears that a nitric oxide metabolite measured in the blood after exercise may discriminate between healthy patients and those with cardiovascular disease and is related with a physiological response of the artery diameter," Allen said. "Also, these biochemical and physiological markers can be positively influenced by exercise in patients who are at risk for cardiovascular disease."

The number of tests for health risks and the accuracy of the predictions made from test results will steadily increase. DNA sequence testing will be just one of many kinds of tests that will be used to more accurately predict health risks.