<story><title>A woman who can smell Parkinson&apos;s disease</title><url>http://www.bbc.co.uk/news/uk-scotland-34583642</url></story><parent_chain></parent_chain><comment><author>bazillion</author><text>This reminds me of when I was in the Navy -- at one point I had lived with hundreds of other guys in a ship&amp;#x27;s berthing and at another duty station I mentioned to a coworker that I could determine someone&amp;#x27;s race from their sweat.  Of course, they called bullshit on that statement (as I&amp;#x27;d imagine most on here would) and we tested it out with 4 guys (1 black[1], 2 white[2], 1 hispanic[3]) who sweated into the same size shirts, and I was able to identify them with 100% accuracy.  Another time, I walked into a cubicle, wrinkled my nose, and said &amp;quot;Man!  It smells like an old deck of cards in here!&amp;quot;.  One of the guys standing next to me then pulled out a rather well-played-through deck of cards out of his pocket.&lt;p&gt;One of the reasons people give for the difference in smell are the difference in foods that different cultures eat.  I definitely know this is not the case, as everyone on that ship was eating the exact same food, and their smells were extremely distinct.&lt;p&gt;I understand that lack of science applied to my specific anecdotes, but I think there&amp;#x27;s something to be said for having a keen sense of smell, since people are already geared towards smelling other people&amp;#x27;s sweat to determine immunocompatibility[4].&lt;p&gt;[1] A black person&amp;#x27;s sweat is the one I can identify with absolute certainty, as it&amp;#x27;s completely unmistakable for anything else&lt;p&gt;[2] A white person&amp;#x27;s sweat smells like a distinct type of onion to me&lt;p&gt;[3] I couldn&amp;#x27;t really identify his race if it were just this shirt, but had that one by process of elimination.&lt;p&gt;[4] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Major_histocompatibility_complex_and_sexual_selection#MHC-mediated_mate_choice:_case_studies&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Major_histocompatibility_compl...&lt;/a&gt;</text></comment>
<story><title>A woman who can smell Parkinson&apos;s disease</title><url>http://www.bbc.co.uk/news/uk-scotland-34583642</url></story><parent_chain></parent_chain><comment><author>IkmoIkmo</author><text>The thing that most surprised me were the odds that a person in the control group (no parkinson&amp;#x27;s), actually did have parkinson&amp;#x27;s (diagnosed early according to the woman) and was diagnosed later to indeed have parkinson&amp;#x27;s.&lt;p&gt;After all, the prevalence is 0.3% in the general population. The odds at least one of the six in the control group had parkinson&amp;#x27;s is around 2% (even less considering it&amp;#x27;s already a filtered audience in a way). Not impossible but very unlikely, which incidentally makes her insistence of that single particular person to have PD all the more interesting.&lt;p&gt;There&amp;#x27;s definitely something there, looking forward to more testing.</text></comment>