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← What your breath could reveal about your health

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Showing Revision 9 created 02/07/2019 by Oliver Friedman.

  1. I have a tendency to assume the worst,
  2. and once in a while,
    this habit plays tricks on me.
  3. For example, if I feel
    unexpected pain in my body
  4. that I have not experienced before
    and that I cannot attribute,
  5. then all of a sudden, my mind
    might turn a tense back into heart disease
  6. or calf muscle pain
    into deep vein thrombosis.
  7. But so far, I haven't been diagnosed
    with any deadly or incurable disease.
  8. Sometimes things just hurt
    for no clear reason.
  9. But not everyone is as lucky as me.

  10. Every year, more than
    50 million people die worldwide.
  11. Especially in high-income
    economies like ours,
  12. a large fraction of deaths is caused
    by slowly progressing diseases:
  13. heart disease, chronic lung disease,
    cancer, Alzheimer's, diabetes,
  14. just to name a few.
  15. Now, humanity has made tremendous progress
    in diagnosing and treating many of these.

  16. But we are at a stage
    where further advancement in health
  17. cannot be achieved only
    by developing new treatments.
  18. And this becomes evident
    when we look at one aspect
  19. that many of these
    diseases have in common:
  20. the probability for successful treatment
  21. strongly depends on
    when treatment is started.
  22. But a disease is typically only detected
    once symptoms occur.
  23. The problem here is that, in fact,
    many diseases can remain asymptomatic,
  24. hence undetected,
    for a long period of time.
  25. Because of this, there is
    a persisting need for new ways
  26. of detecting disease at early stage,
  27. way before any symptoms occur.
  28. In health care, this is called screening.
  29. And as defined by
    the World Health Organization,

  30. screening is "the presumptive
    identification of unrecognized disease
  31. in an apparently healthy person,
  32. by means of tests ... that can be applied
    rapidly and easily ..."
  33. That's a long definition,
    so let me repeat it:
  34. identification of unrecognized disease
  35. in an apparently healthy person
  36. by means of tests that can be applied
    both rapidly and easily.
  37. And I want to put special emphasis
    on the words "rapidly" and "easily"
  38. because many of the existing
    screening methods
  39. are exactly the opposite.
  40. And those of you
    who have undergone colonoscopy
  41. as part of a screening program
    for colorectal cancer
  42. will know what I mean.
  43. Obviously, there's a variety
    of medical tools available

  44. to perform screening tests.
  45. This ranges from imaging techniques
    such as radiography
  46. or magnetic resonance imaging
  47. to the analysis of blood or tissue.
  48. We have all had such tests.
  49. But there's one medium
    that for long has been overlooked:
  50. a medium that is easily accessible,
  51. basically nondepletable,
  52. and it holds tremendous promise
    for medical analysis.
  53. And that is our breath.
  54. Human breath is essentially
    composed of five components:

  55. nitrogen, oxygen, carbon dioxide,
    water and argon.
  56. But besides these five, there are
    hundreds of other components
  57. that are present in very low quantity.
  58. These are called volatile
    organic compounds,
  59. and we release hundreds,
    even thousands of them
  60. every time we exhale.
  61. The analysis of these volatile
    organic compounds in our breath
  62. is called breath analysis.
  63. In fact, I believe that many of you
    have already experienced breath analysis.
  64. Imagine: you're driving home
    late at night,
  65. when suddenly, there's
    a friendly police officer
  66. who asks you kindly but firmly
  67. to pull over and blow
    into a device like this one.
  68. This is an alcohol breath tester
  69. that is used to measure
    the ethanol concentration in your breath
  70. and determine whether driving
    in your condition is a clever idea.
  71. Now, I'd say my driving was pretty good,
  72. but let me check.
  73. (Beep)

  74. 0.0, so nothing
    to worry about, all fine.

  75. (Laughter)

  76. Now imagine a device like this one,

  77. that does not only measure
    alcohol levels in your breath,
  78. but that detects diseases
    like the ones I've shown you
  79. and potentially many more.
  80. The concept of correlating
    the smell of a person's breath
  81. with certain medical conditions,
  82. in fact, dates back to Ancient Greece.
  83. But only recently, research efforts
    on breath analysis have skyrocketed,
  84. and what once was a dream
    is now becoming reality.
  85. And let me pull up this list again
    that I showed you earlier.
  86. For the majority of diseases listed here,
  87. there's substantial scientific evidence
  88. suggesting that the disease
    could be detected by breath analysis.
  89. But how does it work, exactly?

  90. The essential part is a sensor device
  91. that detects the volatile
    organic compounds in our breath.
  92. Simply put: when exposed
    to a breath sample,
  93. the sensor outputs a complex signature
  94. that results from the mixture of volatile
    organic compounds that we exhale.
  95. Now, this signature represents
    a fingerprint of your metabolism,
  96. your microbiome
  97. and the biochemical processes
    that occur in your body.
  98. If you have a disease,
  99. your organism will change,
  100. and so will the composition
    of your exhaled breath.
  101. And then the only thing that is left to do
    is to correlate a certain signature
  102. with the presence or absence
    of certain medical conditions.
  103. The technology promises
    several undeniable benefits.

  104. Firstly, the sensor can be miniaturized
  105. and integrated into small,
    handheld devices
  106. like this alcohol breath tester.
  107. This would allow the test to be used
    in many different settings
  108. and even at home,
  109. so that a visit at the doctor's office
  110. is not needed each time
    a test shall be performed.
  111. Secondly, breath analysis is noninvasive

  112. and can be as simple as blowing
    into an alcohol breath tester.
  113. Such simplicity and ease of use
    would reduce patient burden
  114. and provide an incentive
    for broad adoption of the technology.
  115. And thirdly, the technology is so flexible

  116. that the same device could be used
  117. to detect a broad range
    of medical conditions.
  118. Breath analysis could be used to screen
    for multiple diseases at the same time.
  119. Nowadays, each disease typically requires
    a different medical tool
  120. to perform a screening test.
  121. But this means you can only find
    what you're looking for.
  122. With all of these features,
    breath analysis is predestined

  123. to deliver what many traditional
    screening tests are lacking.
  124. And most importantly,
  125. all of these features should
    eventually provide us
  126. with a platform for medical analysis
  127. that can operate at attractively
    low cost per test.
  128. On the contrary, existing medical tools
  129. often lead to rather high cost per test.
  130. Then, in order to keep costs down,
  131. the number of tests
    needs to be restricted,
  132. and this means (a) that the tests
    can only be performed
  133. on a narrow part of the population,
    for example, the high-risk population;
  134. and (b) that the number of tests
    per person needs to be kept at a minimum.
  135. But wouldn't it actually be beneficial
  136. if the test was performed
    on a larger group of people,
  137. and more often and over a longer period
    of time for each individual?
  138. Especially the latter would give access
    to something very valuable
  139. that is called longitudinal data.
  140. Longitudinal data is a data set
    that tracks the same patient

  141. over the course of many months or years.
  142. Nowadays, medical decisions
    are often based on a limited data set,
  143. where only a glimpse
    of a patient's medical history
  144. is available for decision-making.
  145. In such a case,
  146. abnormalities are typically detected
  147. by comparing a patient's health profile
  148. to the average health profile
    of a reference population.
  149. Longitudinal data would
    open up a new dimension
  150. and allow abnormalities to be detected
  151. based on a patient's own medical history.
  152. This will pave the way
    for personalized treatment.
  153. Sounds pretty great, right?

  154. Now you will certainly have a question
    that is something like,
  155. "If the technology is as great as he says,
    then why aren't we using it today?"
  156. And the only answer I can give you is:
  157. not everything is as easy as it sounds.
  158. There are technical
    challenges, for example.
  159. There's the need for
    extremely reliable sensors
  160. that can detect mixtures
    of volatile organic compounds
  161. with sufficient reproducibility.
  162. And another technical challenge is this:
  163. How do you sample a person's breath
    in a very defined manner
  164. so that the sampling process itself
  165. does not alter the result of the analysis?
  166. And there's the need for data.
  167. Breath analysis needs
    to be validated in clinical trials,
  168. and enough data needs to be collected
  169. so that individual conditions
    can be measured against baselines.
  170. Breath analysis can only succeed
  171. if a large enough data set
    can be generated
  172. and made available for broad use.
  173. If breath analysis
    holds up to its promises,

  174. this is a technology
    that could truly aid us
  175. to transform our health care system --
  176. transform it from a reactive system
  177. where treatment is triggered
    by symptoms of disease
  178. to a proactive system,
  179. where disease detection,
    diagnosis and treatment
  180. can happen at early stage,
  181. way before any symptoms occur.
  182. Now this brings me to my last point,
    and it's a fundamental one.

  183. What exactly is a disease?
  184. Imagine that breath analysis
    can be commercialized as I describe it,
  185. and early detection becomes routine.
  186. A problem that remains
    is, in fact, a problem
  187. that any screening activity has to face
  188. because, for many diseases,
  189. it is often impossible to predict
    with sufficient certainty
  190. whether the disease
    would ever cause any symptoms
  191. or put a person's life at risk.
  192. This is called overdiagnosis,
  193. and it leads to a dilemma.
  194. If a disease is identified,
  195. you could decide not to treat it
  196. because there's a certain probability
    that you would never suffer from it.
  197. But how much would you suffer
  198. just from knowing that you have
    a potentially deadly disease?
  199. And wouldn't you actually regret
    that the disease was detected
  200. in the first place?
  201. Your second option
    is to undergo early treatment

  202. with the hope for curing it.
  203. But often, this would not come
    without side effects.
  204. To be precise:

  205. the bigger problem is not overdiagnosis,
  206. it's overtreatment,
  207. because not every disease
    has to be treated immediately
  208. just because a treatment is available.
  209. The increasing adoption
    of routine screening
  210. will raise the question:
  211. What do we call a disease
    that can rationalize treatment,
  212. and what is just an abnormality
    that should not be a source of concern?
  213. My hopes are that routine screening
    using breath analysis
  214. can provide enough data and insight
  215. so that at some point,
    we'll be able to break this dilemma
  216. and predict with sufficient certainty
  217. whether and when to treat at early stage.
  218. Our breath and the mixture of volatile
    organic compounds that we exhale

  219. hold tremendous amounts of information
    on our physiological condition.
  220. With what we know today,
    we have only scratched the surface.
  221. As we collect more and more data
    and breath profiles across the population,
  222. including all varieties of gender,
    age, origin and lifestyle,
  223. the power of breath analysis
    should increase.
  224. And eventually, breath analysis
    should provide us with a powerful tool
  225. not only to proactively detect
    specific diseases
  226. but to predict
    and ultimately prevent them.
  227. And this should be enough motivation
  228. to embrace the opportunities
    and challenges
  229. that breath analysis can provide,
  230. even for people that are not
    part-time hypochondriacs like me.
  231. Thank you.

  232. (Applause)