Following my (obsessive) interest in my CPAP readings, I tried to find articles which related to central apnea as opposed to obstructive apnea. I didn't find very much, but one web site containing the writings of Dr Stasha Gominak make a very strong argument that apnea - as well as many other maladies or misfunctions - are due to a low level in vitamin D.
Whilst I was absorbing these articles, there was published in the Israeli newpapers an item stating that the Ministry of Health considers that at least 50% of Israeli adults suffer from vitamin D deficiency (don't quote me on this number) and so the Ministry is demanding mandatory addition of vitamin D to milk.
This is somewhat surprising as Israel (unfortunately) has too much sun and fifteen minutes exposure per day is supposed to be sufficient to create the necessary amount of vitamin D. On the other hand, Dr Gominak points out that we all try to stay indoors, and when we do venture out, we slather ourselves with creams which prevent the ultraviolet light from reaching our skins (a very important point for me, as I have just had another BCC growth removed).
The proportion of dairy products, rich in vitamin D, in the Israeli diet is also comparatively high.
I discussed these points last week when I saw my doctor last week. It might be possible that my headaches - and indeed, sleep apnea - are caused by a lack of vitamin D, and I am not aware of ever having this level measured. He agreed to have my blood tested for this vitamin (really a hormone, as the body secretes it) along with the tests of kidney functions that he wants.
I took the blood tests a few days later and received the results the same day. Unfortunately, there was no result for vitamin D. I waited a few days, in the hope that maybe the missing result would be forthcoming, but no such luck. I suspect that the doctor forgot to add the test to the ones that he ordered via the computer (he also forgot to write one prescription for analgesics).
So unfortunately, I don't know whether my vitamin D level is satisfactory. There is argument as to what a satisfactory level actually is; according to my doctor, the Ministry of Health uses the level 75 ng/ml in blood, whereas Dr Gominak would be satisfied with the range 60-80 ng/ml blood. The high level which the Ministry requires may be one reason why it considers so many people to have a deficiency.