Mike,

Excellent post.  It's also a great example of critical thinking and reasoning.  For example, I'm comforted to have found that a vitamin D3 deficiency is common among CHers with active CH and that repleting that deficiency by taking the anti-inflammatory regimen with 10,000 IU/day vitamin D3 stops CH occurrence and prevents further occurrence in a high percentage of CHers. 

We've gathered sufficient evidence over the last six years to prove the above statements and in the process, establishing that a very clear inverse relationship exists between the frequency of CH and the serum concentration of 25(OH)D, the first metabolite of vitamin D3 that is used to measure its status. 

Making the case for causality is a bit more difficult.  The best evidence for causality comes from many of the episodic CHers who stopped taking this regimen at the end of their normal cycle only to have their CH return as usual with the next CH cycle.  There are also a few risk takers like me, who intentionally stop taking this regimen until their CH return. 

In doing this, we've established the logic that by taking vitamin vitamin D3, a CHer with active CH can stop their occurrence and prevent recurrence.  Moreover, if a CHer, in complete remission from CH while taking vitamin D3, stops the intake of vitamin D3 and experiences a recurrence of CH after a week to a month, (this coincides with 25(OH)D serum concentration half-life), the case for causality gains strength. 

Bottom line...  Vitamin D3 is a great CH preventative...  but it isn't a cure... at least not as defined by Merriam Webster in the following:

a :  recovery or relief from a disease - Yes

b :  something (such as a drug or treatment) that cures a disease, i.e., Quinine is a cure for malaria. - No

c :  a course or period of treatment, i.e., take the cure for alcoholism - No

d :  a complete or permanent solution or remedy. - No

What we can say, at best, is a vitamin D3 deficiency is a contributing factor in the pathophysiology and etiology of CH and that vitamin D3 taken at a pharmacological/therapeutic dose is effective in preventing CH.

For most of us CHers, the anti-inflammatory regimen has become "a way of life..."  i.e., something we take daily/weekly to maintain a very good quality of life.

That leads us to a logical conclusion that there is no cure, as yet, for cluster headache, at least as defined by Merriam Webster. 

This makes vitamin D3 preventing cluster headache consistent with ascorbic acid (vitamin C) preventing scurvy, vitamin D3 preventing rickets, Vitamin B1(thiamine) preventing Beri Beri and vitamin B3 (niacin) preventing Pellagra.

What your post points out is important, there are CH triggers...  I look at triggers as clues that may help us at some point in time in the future, lead us to the actual cause.

Take care,

V/R, Batch