Skip to comments.Vitamin D and Cancer Mortality: Not to be Taken Lightly
Posted on 05/12/2011 10:41:03 AM PDT by dangerdoc
Abstract The association is not clear-cut, according to an assessment of data from the Third National Health and Nutritional Examination Survey.
Introduction Ultraviolet radiation has various deleterious effects but a positive influence on vitamin D metabolism. Dermatologists typically recommend that patients use sunscreen and take other precautions to prevent sunburn, nonmelanoma skin cancer, melanoma, and cutaneous photoaging. This practice is increasingly being scrutinized because much of the population is vitamin D deficient and because several healthful effects have been attributed to vitamin D, including a potential cancer-protection effect. To assess the association between baseline serum 25-hydroxyvitamin D levels (25[OH]D) and cancer mortality, researchers prospectively examined data on 16,819 participants in the Third National Health and Nutritional Examination Survey (NHANES III). Levels of 25(OH)D were measured once, in spring or summer in higher latitudes and in fall or winter in lower latitudes.
During a mean follow-up of 13.4 years, 884 participants died of cancer. Cancer mortality did not correlate with serum 25(OH)D in the total population or in men and women analyzed separately. However, men with 25(OH)D levels >80 nmol/L had a significantly higher cancer mortality rate than those with levels <50 nmol/L. Among women in the summer/higher-latitude group, the overall cancer risk trended significantly lower with higher 25(OH)D level. Serum 25(OH)D levels were not associated with cancer mortality among non-Hispanic white, non-Hispanic black, and Mexican-American subgroups. Colon cancer deaths trended nonsignificantly lower with higher 25(OH)D levels. In men, but not women, elevated baseline serum 25(OH)D was associated with increased deaths from lung cancer and from digestive tract cancers other than colorectal cancer. No clear trend was apparent for female breast cancer, prostate cancer, or combined deaths from non-Hodgkin lymphoma or leukemia.
If I have this right then men with significantly higher than average vitamin D levels had significantly higher overall cancer rates. Vitamin D levels were seasonally determined.
Perhaps the men with significantly higher vitamin D levels reached those levels with significant seasonal exposure to sunlight.
I read this the opposite- that higher Vitamin D is better for you
The significance is that this is the first study I have seen that looks at Vitamin D levels before cancer is diagnosed. I don’t think they are arguing that Vitamin D causes cancer rather that the study does not confirm a protection hinted at in earlier studies.
Measuring vitamin D levels in people already diagnosed with cancer in not a good way to determine causation and suffers potential confounding and bias.
Men who had higher vitamin D levels had a significantly higher rate of cancer when followed over time in this study.
I can't speak for others, from my understanding everyone absorbs D differently. If you have an auto immune diseases your body soaks up D. But, I've been taking anywhere from 2000IU a day up to 15,000 a day for 8-9 years and my D level has only been up to around 90 one time. Every other time they've checked it it's been around 50 or so. So it's very hard to get to much D unless your along the sun belt. You just want to make sure you don't get to much, but, don't let some doc scare you into thinking if you take 2000 a day you'll get to much. Most people need around 4000 a day. 30 minutes or so in the sun(the farther north you are, the less you get) will give you around 10,000.
Use sunscreen for the beach or the pool, but they take it to ridiculous levels these day. I thought my son’s preschool was going to call social services because we told them he didn’t need it to go outside for recess. He is the only kid in the class without sunscreen. Sorry, but 20 minutes outside fully clothed isn’t going to hurt him.
Greater than 80 nmol/L is not higher but much higher, no? I believe the current goal is 50 nmol/L.
It might also matter that the levels were measured seasonally with the northern latitude measurements being in the time of year with the longest days.
No deficency is lack of vitamin D
Did you have to sign a release?
The mom’s club has reached consensus........ sunscreen saves lives.
I have an autioimmine diease and the Doctor has me on prescription vitamin D most of the time because my levels are too low.When she first measured my levles were in the siungle digits.It is impossoble to get too much vitamin D because the body will flush the overage.They want to keep my levels over 50 which is a normal level but it’s hard to keep it there.This week I started back on the script at 10,000iu 5 days in a row and then once a week after that trying to get it back to 50 or over.
"However, men with 25(OH)D levels >80 nmol/L had a significantly higher cancer mortality rate than those with levels <50 nmol/L."
According to my doctor it is impossible to get that much from the sun further north than Atlanta except for about 2 weeks in the middle of July from the sun.It has to do with the angle of the sun and is why most people in the north are vitmain D deficient.
That is terrible that they insist this for the kids. I am deficent and my doctor told me unless I was going to be i the sun for more than an hour to skip the sunscreen.
80 is a near impossible level to get to.One would have to be taking more than 10,000iu a day for weeks to even get to that level. The normal level is 50 but most people who live in the north and are over 40yo most likely hover at about 35 most of the year.
I reread that and I am still right a level 25 is too low that is not a high level of vitamin D and is in the deficient level.50 is considered normal.
The study does not make me concerned that elevated Vitamin D level causes cancer. That is probably just a fluke of doing too many subanalysis tests. If you do 10 tests with a p=.05 you will have a 50% false positive rate even higher if you are looking for both a positive and negative change.
The interesting thing is that in the whole test and looking at all sub groups, it does not look like low Vitamin D levels is a statistically significant risk factor for cancer, even considering the seasonal factor in measurement.
How is this for a confounder. Since the effect of high Vitamin D was seen in men, as a population which men would have the highest Vitamin D levels?
Out of all the common trades, I’m thinking construction. Construction worker’s have much higher smoking rates that the general population. Smoking is related to both lung and non-colon GI cancer. This is a significant confounder.
As I mention to Decimon, I don’t think this study shows that elevated Vitamin D levels are a cancer risk. If they were, you would expect to see it across race and gender. The interesting thing is that low Vitamin D levels was not found to be a significant cancer risk in any subgroup or in the study as a whole.
Not sure, it would have been my wife that signed it.
Can’t find any more info on this study. They have a lock on it though it’s not a new publish.
I have the same problem. Seems like I take a lot and struggle to keep my D level above 50. One of my docs says that he thinks the level should be around 100-110. That’s what a life guards level would be. Can you get in the sun at all? 10-15 minutes a day without sun tan lotion. As long as you get no burn or tan. The darker your skin, the longer it takes in the sun to get vit. D. Also weight can have an affect too. The heavier you are the longer it takes to get vit. D from the sun. Also the farther north you are the less D you get from the sun. Where I live you could stay out in the sun all day long in the winter and get none.
Your welcome!!! Just don’t stay in the sun 30 mintues :) You’ll get a tan or burn. The usually recommendation is 10-15 minutes a day without sun tan lotion, in mid-day sun. Avoid any kind of burn or tan, both will inhibit your absorption of vitamin D.
I am about as white as a person could be and do burn easily.I’m fairy far north,SE Ohio, too so the sun does little most of the year. I don’t think they have ever got my level higher than 60.Most likely I have alway been deficient thus the problem with type 1 diabetes at 9yo?
Correlation is not causation. Repeat over and over in your mind every time you read a medical study. Researchers and journalists are always forgetting this.
You can get to much D and if you do, that's not a good thing. But, it takes a lot and is pretty hard to do. The other thing I found out is don't take your D with vitamin A. The D won't get absorbed as well.
“by the idiots who are now giving us this bogus study information”
They looked at Vitamin D levels and then followed the group for years to see what happened, then published the results. What exactly do you think is bogus?
This is what the author had to say about the paper.
“The large NHANES III database provides a unique opportunity to evaluate in detail the relation between vitamin D and diseases in the U.S. Study limitations include the measurement of vitamin D levels only at baseline. The findings suggest that we don’t yet have the final word on the relationship between vitamin D and human health and that claims that vitamin D protects against specific cancers are not necessarily supported by the facts. Dermatologists can use this information to counter people’s presumption that sun exposure or tanning bed use will protect against cancer mortality; in fact, such exposure may actually increase deaths from some cancers.”
This is what is bogus:
Suppose a guy was in the sun all the time, yet he was using Sun block. Now, he never really got burned but was in the sun a hell of lot and the sun block he was using (and we were all using it) was blocking the production of Vitamin D yet allowing the UV types through that caused cancer. Imagine how long he would have to be in the sun to have high levels of Vitamin D, and then imagine all those cancer causing UV rays that were unblocked until a few years ago by sunblocks.
In essence, Sun block was a terrible thing, it was blocking Vitamin D production while letting through the truly harmful rays.
So, in reality, we won’t know anything about this until 20 years from now. The truth is, cancer rates are in large part really bad because we were told to use sun block, if we had no sunblock we would have truly protected ourselves, gotten a color slowly until we could stay in the sun all day without burning, which is what I do.
And, in central america and so on where they are in the intense sunlight all day long without any sunblock the forms of cancer we get are nearly unheard of. And don’t claim it’s thier skin color, unless you mean getting a good tan on your skin is really healthy.
I honestly can’t follow what you are saying. Do you think that UV light is causing increased lung and GI cancer?
If you look a few posts up, you can see my theory on the association.
That goes to UV exposure and not vitamin D oral supplement. Can't tell if the study made any distinction.
I think the point is that there was some thought that the higher risk of skin cancer was balanced by a lower risk of other cancers but if there is no trade off then the dermatologists win the argument.
Personally I don’t care if I have wrinkles or a few skin cancers.
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