I mostly suffer from headache because of dehydration, surprisingly it was not not covered in this article. I beleive one of the main reason is water loss, or not drinking enough water and leaving the body dehydrated causes headaches in our Indian subcontinent.

@Benny I think dehydration is covered under point number 7.

"You are more vulnerable to a headache if you are dehydrated or have not received the proper nutrition."

But I guess it might have deserved a point by itself.

Very interesting article. I particularly get headaches for several of these triggers, perfumes, hair clips, some vegetables, eating dairy too often, long time in the computer screen, cigarettes, liquor and hormonal changes. As you will see, my case is very complex. When I talk with some people, they believe it is my idea, but I've always felt that it is not. I read this I am now safer than before. I find it best to take ibuprofen because acetaminophen makes me sick in the long run. Thanks for clarifying that ideas are not just mine.