Hi vintage
Your parathyroid is right at the top end of normal. That is a typical response to low vitamin d.
The mechanism is as follows... Your blood calcium needs to be maintained in a tight range , i.e the normal range. IF your body is needs to absorb more calcium from your food , then the Parathyroid, PTH, hormone increases , which is instructing the kidneys to manufacture more vitamin D hormone ( 1,25 didydroxyD3 ) , which then enables your intestines to absorb a greater percentage of the total calcium that you ingest. IF you have low levels of the pre hormone i.e. 25hydroxyD3 - which is the measured value of your vitamin D level, i.e. 52, then you might not be able to make enough hormone ( 1,25dihydroxyD3 ) . So your endocrine system increases the PTH hormone level in an attempt to raise your calcium absorption, in a feedback loop. One of the effects of higher PTH could be to cause your reservoir of calcium , i.e. your bones, to donate calcium to your blood. In order to maintain your blood calcium in the normal range. A higher PTH, CAUSED by low Vitamin D , is called secondary hyperparathroidism. It is not a problem with your parathyroids , it is simply a normal response to low vitamin D, OR insufficient calcium consumption. Are you dairy free ? Do you eat plenty of calcium containing food i.e. greens etc.
At this time of year , your Vitamin D level will be around maximum, from natural sources, i.e. sunlight and food. Sunlight does not contain UVB over winter , that is mid Oct to mid April , so our vitamin D levels drop over winter, unless you supplement. We cannot make vitamin D in our skin over winter. So we rely on food. Vegetarian foods , have practically no vitamin D , it is a mammalian hormone , so there are small amounts in meat and animal products. IF you are vegetarian ? , you may be absorbing hardly any by mouth.
It seems that you are not getting enough Vitamin D, for whatever reason, from natural sources. i.e. food and sunlight. However, the fact that you dropped from 92 to 52 over summer means that if unsupplemented, you will continue to drop over winter.
The reasons that you don't have much vitamin D in your blood , could be,
1. Inability to absorb from food . you may have intestinal problems, IBS, Crohn's, Coeliacs, Gall Bladder , bile problem etc etc
2. Insufficient sunlight on skin during the summer. bear in mind that you can only make vitamin D when sunlight contains UVB radiation , that is between 11 am and 3 pm , in the summer months. Outside of those times , including all winter you cannot make vitamin D in your skin. That is just the basic physics of sunlight. You do need to expose a reasonable amount of skin , not just face and hands.
- Sunscreens. IF you apply factor 15 or more during the time that UVB is present , then the sunscreen absorbs the UVB , and prevents the skin absorbing that UVB , and stops Vitamin D manufacture. It is recommended that you leave sunscreens off for 20 mins
- You may simply not get enough , i.e you may avoid sunlight , not eat vit d containing food such as oily fish etc .
Your body requires about 70 IU of Vit D per day , every day , per kilogram of Vit D. That is from all sources, food , sunlight and supplement.
Most people , on average , will raise their blood level by 25 nmol/L for every 1000 IU of daily supplement. IF you stop supplementation , then you blood level will drop, as you have found.
Don't stop supplementation after 3 months. Your levels will fall again. When your doctor does the test, perhaps convince him to do a calcium test again , just to check things are ok. There is just a slight possibility that your parathyroid level is high not because of Low vitamin D. I would expect your parathyrroid to come down to middle of the range or less , once you have a better level of Vit D. IF it doesn't then that should be explored. Any calcium measurement above normal should be explored. It is very unlikely though !
From your description above , you are likely to need around 3000 to 5000 IU per day, ongoing. To maintain a level , preferably above 100.
IF you do have any kind of absorptive issues , such as those gut problems mentioned above, you might consider an oral Vitamin D spray , which will be absorbed directly into the blood stream , and avoid the digestive system.
I hope this long message is helpful,
Best of Luck ,
If you need anymore info ….get back to me , or have a look at some of my other post here on Mumsnet , where I have explained a bit more about Vitamin D.
BTBH