That's the Bell Curve which shows the most common type of distribution for a variable. It's called a "bell curve" -- d'oh! -- because the graph looks like a bell.
I started thinking about the bell curve and health after talking recently with a friend who has a particularly virulent cancer. He was told he could expect to live another 12 to 18 months. For those with this cancer, that prognosis may reflect what will happen to the 68.2% shown in the dark blue area. The 0.1% at the far left represents the few who die within a week or two of the diagnosis. Let's hope my pal will join the 0.1% at the far right, who end up living for years after the diagnosis.
I also thought of my dear friend Lily who has been my role model for "aging with zest" and is now age 93. She's surely out there somewhere beyond the 2.1% marker on the right in a bunch of variables: age, energy, quality of life. It's unlikely I'll be so lucky.
Then I started thinking about the bell curve's applicability to my health issues. For example, my doctors' prescriptions for the dosage and timing of the meds I take probably come from studies on what's best for those in the dark blue. But is that where I am?
On an issue I've been writing about a lot lately -- dietary supplements -- the hype for a particular vitamin (D is the current darling) or supplement (antioxidants are up at the top of the current hit list) often comes from anecdotal reports of the phenomenal results achieved by a few individuals who may well be way out on the O.1% right-hand tail of any chart of individual responses to popping the vitamin or supplement pill.
But, on the other hand, warnings regarding potential serious side effects from taking a particular medication or supplement may reflect the experience of a few who would be out on the left-hand tail of the curve. Meanwhile, the 50% to the right of the median line are getting some benefit from it.
This is the first in a series of posts I plan to make over the next weeks, as I explore what happens if I use the bell curve to consider my own health issues. But the series will be interrupted, frequently I hope, because I'll also be sending reports (and photos) of my return to Nepal for the wedding of my housemate Nimesh and his arranged-marriage bride Bahwana. I've met the bride-to-be on Skype and can easily understand how Nimesh fell immediately in love with her. On a bell curve of successful, happy marriages, I predict their marriage will be off the scale on the right hand side.