I don't know about that, actually. Caffeine is the active ingredient in (low-power, over-the-counter) migraine medication, because it has anti-inflammatory properties. People who have chronic headaches may be unintentionally self-medicating with caffeine; for them, the caffeine withdrawal period becomes concurrent with their regular headaches returning.

More anecdotally, when I don't drink caffeine (and I do go off it for months at a time), I get headaches on and off, about once per week or so. When I do drink caffeine, though, I literally never get headaches.

If I remember correctly, caffeine's purpose in migraine medication is to accelerate the delivery of the payload.

If true, I would find that rather disturbing.

Vasodilation is not necessarily chemically induced, but it is a common-enough proximate cause of headaches (and some other forms of pain) that using a mild vasoconstrictor in addition to an analgesic is more likely to make a general-purpose pain reliever work effectively.

I used to regularly get stress-induced migraines (before I regularly drank anything caffeinated). Then I started drinking 2 cups of tea or coffee per day, which completely cleared up the issue.

Of course, if I go "off schedule," I get a headache now almost immediately.

(http://www.helpforpain.com/arch2000aug.htm)

That site says rebound headache are the most common cause of pain referral to doctors, which is a surprise to me. I would have thought back pain was.

But, in general, yes headache medications can actually cause headaches. Ask your pharmacist.

* lack of exercise

* smoking

near the top

> Too much sugar/fat

I googled it and found that the underlying reason seems to be high blood pressure, which can be caused by extremely high amounts of triglycerines. Unless you eat insane amounts of fat, I think it is easier to lower your blood pressure in other ways (exercising, quitting smoking, reducing sodium intake)

Bad sitting posture, bad chairs and anything that could strain the spinal cord could result in serious issues. A friend was just short of a disk slip because of his sitting posture. He had a bad headache and after a diagnosis that took a month it turned out to be a problem with his spine.

    > Flew

(Pet peeve - sorry - bad personal experience)

Most victims were healthy young adults, in contrast to most influenza outbreaks, which predominantly affect juvenile, elderly, or weakened patients.

The pandemic lasted from June 1918 to December 1920, spreading even to the Arctic and remote Pacific islands. Between 50 and 100 million died, making it one of the deadliest natural disasters in human history. Even using the lower estimate of 50 million people, 3% of the world's population (1.86 billion at the time) died of the disease. Some 500 million, or 27% (≈1/4), were infected.

Once it finally actually rose to the level of a toothache and I got it pulled, the change was enormous.