>>> good morning, everybody. i'm talking to you. welcome to the 12th session. i want to welcome all of you here in the audience, and many, many more, hopefully, at our envision site and our external viewers. >> today, it's all about the bone, and we are going to be focusing on topic of vitamin did and how it's monitored in the united states.
this is a topic that is a little bit different than some of the topics we have covered before, but i'm delighted to see many of you here, interested in this, and i have actually had people from the infectious disease world call and say, are you going to be covering this or that? i actually had a couple of outside consult acts unrelated to cdc call and say, do you need help. i thought that the speakers and experts we have here can't handle it, so i declined.
i want to bring one thing to your attention that as much as we believe the work these days can be done only if 11,000 people public something, there are very few papers where you have one or two people. again the infectious disease world has the top role, in that this is one of the papers that paul is going to be referring to. i didn't count the number of authors, but i would say it's upwards of 50.
just the document, the enormous amount of interest in the topic and scientific community. reminder, this is getting to be boring, i get called can this be viewed on tv and can i have my mother watch me if i'm in the first row of the audience. yes, we can be viewed through iptv and externalened internet sites. we are located at the director's web page, internally and externally.
and again, we are doing the work in parallel with this, and so one of the features that we have done for the science flicks is selection of top ten articles and vitamin d issues -- two of those articles made it to the top ten this week. it's just a coincidence. reminder that this is a continuing education session, and that you can get ce credits, either by participating directly, alive, or taking -- viewing the session, and then confirming that on the web later on.
so, our topics that are coming up, are h1n1, alcohol and malaria. let me just say a couple of words about the -- our speakers today. so as i said, this is a topic that is devoted to vitamin d and healthy bones and some of you who may be familiar with this show may actually enjoy this hilarious group of people. those are our speakers today. they are cliff johnson, christine pfeifer and paul.
they are going to be covering the proud range of how do we monitor the issues, how do we monitor the population status, how we attack challenges when it comes to laboratory methods and what is all of the science tell us, how we can actually put all of these things in practice, and implement policies. let me ask you, for just a couple of reminders. this is for the cdc audience. you may notice there are some orange and green notes, index notes in front of you.
we would like, if you don't mind, for you to write just a sentence or two, if you have attended more than one or two sessions, what are your general impressions. even if you just say i like it, i don't like it, what is it that you like or don't like. please just write, and then drop the card in the box outside of the auditorium, so we can get some feedback. we are getting feedback via web, but i also like to get feedback for people in the audience.
and the second reminder is that tomorrow is the deadline for the submission of the topics for the next round of the grand round, and i received a number, but i wanted to remind you, tomorrow, close of business, is the time to submit your proposals. and with that, dr. frieden is unable to be with us today, but we have -- he has tapes of your remarks, and if we can have his remarks now, please. >> welcome to public health grand rounds. today's session is on the importance of vitamin d.
vitamin d supplementation, reduces osteoporosis, but what is the evidence for additional health benefits? many questions remain about vitamin d. how effective is it, if at all, in reducing cancer, diabetes and heart disease. how much is safe to take. how can be improve the measurement of vitamin d status. what can we do about the inverse care law, whereby those who need the most, get the least and vice versa.
in vitamin d sufficiency. these questions led to a new review of vitamin d intakes by the institute of medicine. we anticipate that that review will be reduced in the coming month or two and today's grand rounds provides the latest evidence of vitamin d effectiveness and safety and explores the challenges we face, measuring and defining vitamin d status. thank you.
>>> thank you, dr. frieden. good morning. my name is cliff johnson. i'm the director of the division of health and nutrition survey at the national center for health statistics, vitamin d is one of the most talked about nutritional issues in the u.s. vitamin d is also an issue globally. in this presentation, i will discuss what vitamin d is and why we need it.
what scientific and public health issues have made it such a talked about issue, and how vitamin d status in the u.s. population is evaluated through the survey. i'll also discuss somal challenges, in assessing vitamin d status and ways to address things. vitamin d is a fat soluble vitamin that helps the body absorb calcium. it is needed for bone growth and bone remodelling. vitamin d has other roles in human health, including
modulation of neuromuscular and immune function, and reduction of inflammation. the human requirement for vitamin d can be met by exposure through sunlight and diet and supplements. most people meet their vitamin d requirements through exposure to sunlight. people who avoid the sun, who cover their bodies with sunscreen or clothing or live in northern climates would likely need good sources of vitamin d in their diets or take you
supplement. very few foods in nature contain vitamin d. primary sources include fortd fieed milk. some yogurt. some cereals and fruit juices and the flesh of various fatty fish. vitamin d is also available in vitamin and mineral supplements. vitamin d is -- that comes from foods, supplements and the sun is biologically unearthed.
it is rapidly taken up and transported to the liver and converted to the circulating form of 25 hydroxy vitamin d. then to the active form. 125, dihydroyx vitamin d in the kidney. the production of 125 dihydroxy vitamin d is regulated by horm moan. breast fed infants, older adults, people with limited sun exposure, people with dark skin, feet with fat malabsorption, people who are obese or people who have undergone bypass
surgery, these groups are in increased risk because of higher physiological requirement, diets limited in vitamin d or other environmental factors such as limited sun exposure. low levels of vitamin d. less than 27.5 per liter is shown to be associated for high risk for ricketts in children. fortification of milk with vitamin d, cases are extremely rare. in adult, adequate levels of vitamin d intake -- inadequate
levels of vitamin d leads to bone pain and muscle weakness and possibly fractures especially in the elderly population. in recent years, low vitamin d levels have been associated with increased risk for numerous other health outcomes, including various cancers, cardiovascular disease, auto immune disease, dementia, diabetes and glucose intolerance. these are based on eek logic or observational stu studies, the cause and effect has not been proven for most associations.
at the same time. excessive amounts of vitamin d in blood can become toxic and produce health problems. excess as well as deficiency is important with respect to vitamin d. what is clear today is that vitamin d is of great interest, not only to the public health research community but to the general population and media. this slide shows just a few examples of headlines in the
past two years, related to vitamin d, and its reported relationship to many public health diseases and conditions. others in the research community encourage caution, relative to the merits of vitamin d and various disease points. for example, the journal of epidemiology, expresses concern that vitamin d may just be the latest in a long list of nutrients, learned to various forms of cancer, all of which were eventually shown in randomized clinical trials, to be shown not to be the panacea for most forms of cancer.
thus, at this time, there's no general consensus with respect to vitamin d and various health outcomes. we have an obvious need to know what the status of the u.s. population is, and whether it's changed over time. it is also important to know how much diet is contributing to vitamin d status and what foods contributing the most vitamin d for the population. as well as dietary supplements supply the sufficient amount for the pop lakes taking them.
finally the scientific and public policy community as well as public immediate to know how much vitamin d do we need. how much is too much. a number of sources of information provide valuable data to inform the research and public health policy community and their ongoing discussion of the importance of vitamin d and health outcomes. they include clinical research study, randomized clinical trials and population-based surveys, or surveillance
systems. public health policy or intervention programs use all of these sources of information. one critical set of information needed is the status of population, now and in the past. the nation health and nutrition examination survey, whose primary objective, is to assess the health and nutritional status of adults and children in the united states, is the most significant population-based survey that provides data to
inform the scientific and public health community on a variety of nutrition and public health topics, including vitamin d. it's been unique on the critical source of data for the past 50 years, first as a targeted survey in the 1960s, then as a periodically conducted survey of health and nutrition from the early 1970s, through the mid 1990s. beginning in 1999, the survey became continuous, and continuously conducted as two-year cycle, covering the entire age range of the u.s. noninstitutionalized population.
it provides critical data and data for many public health functions, include examples include weight and height chart, dietary intake. diagnosed and undiagnosed diabetes, folate levels before and after fortification. lead levels in children and population exposure to second hand smoke before and after smoking regulations. this survey has and continued to be responsive and relevant to current and future public health data needs.
assessing the u.s. population and monitoring the status over time has been a focus in the ed haines survey for the last two decades. vitamin d status can be evaluated using vitamin d intake data from foods and supplements or from looking at vitamin d and serum, collecting data associated with vitamin d status is also part of the survey but will not be discussed as part of this presentation. i will first focus on vitamin d from intakes of foods and
supplements. with respect to vitamin d intake from foods and supplements, the primary questions, is intake adequate and what are the groups of concern. the institute of medicine, diet tear reference intake report from 1997 define adequate intake of vitamin d of 200 international units per se for those less than 50 years of age. 400 for those 51 to 70 and 600 for those 71 years of age or older.
also define pregnant and lactating female, guidelines for adequate intention, 200 international units per day. in addition, they also define a tolerable intake for all population groups for 2,000 international units per day. based on analysis of recent dietary data. both foods alone and foods with supplements. much of the u.s. pop u lags is not meeting the recommended adequate intake for vitamin d. this is especially the case for men over the age of 50 years.
in those age groups, only one quarter to one third meet the recommended adequate intake. and for those older age group, dietary supplements is a significant source of vitamin d intake. for female, the pattern of total intake is similar to that for males with the exception of the 14 to 18 yearly girls. fewer than one-third of the 14 to 18-year-old girl, and the women 71 years and older have adequate intake. for female, ages 14 and older, diet tear supplements contribute
significantly to the total vitamin d intake. i will next focus on levels of vitamin d and serum. serum intake is generally accepted as the best indicator of vitamin d status in blood. radio method used to assess 25 hydroxy vitamin d, through the continuous 2005-2006 cycle. however there's a reformation of the meth and before the start of the continuous survey. in the following presentation, dr. pfeifer will address the
complications because of changes, and the resulting implications for interpreting trends in findings over time. there's also disagreement among experts in the most appropriate cut point for optimal health for 25 hydroxy d. since the release of the report in 1997, the cut point of less than 27.5 nanimals per liter has been used to find efficiency status for vitamin d. this cut point was known for associated of increased risk for ricketts and as teo malaysia.
in recent year, other cut points such as 50 or 80 per liter is been proposed as more appropriate cut points for inadequate or at-risk status, especially for other public health concerns and diseases. if these three proposed cut points for vitamin d and adequate efficiency are applied to the data. you come to very different conclusions about the vitamin d status of the u.s. population. at 27.5 nanimals per leader.
the amount is less than 6%. at the cut point of 80 per liter shown in light purple, one concludes that more than 70% of the population has inadequate vitamin d levels. the cut point of 15 per liter. produces inadequacy, about 30% in the population. dipses among race ethnic groups in serum 25 hydroxy d have also been found but the meaning of this is unclear at this time. based on the percent ent ium criteria.
fewer than one third meet the adequate intake for vitamin d based on total intake including supplements as well as food. when you look at serum lefts. fewer than 6% have levels below the value considered inadequate. additional analysis of the data have known that levels decreased from the 80s to 90s to most likely as a response to altered behavior, such as the fact there's increases in body max index, likely increases in sun exposure. a number of interpretation and meth lodic issues, provide both
challenges and opportunities. there are two ways to assess vitamin d intake, as i mentioned, intake and blood levels. the correlation of serum levels with adequacy is only established at 27.5 per liter for children. changes in laboratory methods complicate the interpretation of status over time. and there's no generally agreed upon cut point for vitamin dishtcy or adequacy, thus, all issues that may lead to
misinterpretation of population levels have to be examed carefully and communicated promptly. the institute of medicine is currently reviewing the recommendations for intake of vitamin d as you heard from tanya, along with calcium. their charge is to assess current relevant data and update, as appropriate, dietary reference intake for vitamin d and calcium. including indicators in excess, give aequacy for age or jenner
groups. gives try ort to selecting a critical adverse effect to define a so-called bench mark and identify research caps to address the uncertainties identified in the process of deriving the reference values and evaluating public health implication. the iom report is well under way and expected this report on dietary intakes and updated report for vitamin d an calcium is expected to be completed in the late fall of 2010.
defending on the recommendations and possibly new cut point, further analysis of the data on vitamin d will likely approve and future program guidelines will likely be determined. i would now like to introduce dr. christine pfeifer. >>> good morning. as you heard, sams have been directed from the ed haines survey since 1988. they've used essential rea, developed in the mid 1980s to measure total 25 hydroxy vitamin d.
immunoas i cannot distinguish between the two forms of 25 hydroxy vitamin d and therefore measures a total amount much the original was used during. then the manufacturer, and decision, and reformulated was used in 2005 to 2006. there has come a time in aspecttometry. should be used for 2007 forward. this measured the individual vitamin d forms. several undesirable performance characteristics.
make the long-term monitoring of trends. first it was quite high with the variation of 10 to 20% which made monitoring small percentages over time difficult. second immunoas says are less specific than chemical compounds. and lastly, the ria is less robust than desirable, meaning there are fluk u stations assay performances over time. all of this makes changes over time more difficult. specifically, the change from original to the reformulated
assay produced results that were on average 25% lower which you see on this cartoon. we observed that the reformulated ria fluctuated over time. between 2000 and 2006 the assay performed for periods sometimes higher, sometimes lower than expected. obviously this had impact of monitoring population levels. i will show you this on the next slide. these are from a publication from nchs.
in panel a, you can see the observed standardized means were 10 to 18 nanimals higher. the original ira was used, then in the dark blue bars, were the reformulated assay was used. panel b shows when the values were adjusted for a change in assay, the difference in standardized means were reduced by 10 to 11 per liter. depending on sex. this means the large proportion between the previous difference
between the two surveys were attributable to the changes of original to reformulated assay and not real difference in population levels of vitamin d. just a few months after the paper was published. prior to having the wider sigh tivg community made aware of importance adjusting the data. another group published data from the same set. they decided that levels lower that 29 per lead, more than doubled from 2001 to 2004.
this estimate, however was inflated because they didn't adjust the data for method differences. these twole xs, highlight a couple important points. rather small changes in 25 hydroxy d levels as a result of assay changes can lead to changes in population levels. lack of data adjustment can lead to very different conclusions. and and it's critical to have important messages published. let me give you an outlook to the analytical data we're developing.
this method has improved precision, much higher specificity and because it is calibrated incause with certified standards and verified regularly with reference materials, its robustness or reproduible over time can be more easily maintained. but changing methods, how do we make the past an future data comparable? last summer, the nih office of dietary supplements and cdc sponsored a round table on vitamin issues.
the expert as kree the methodology should be the method. they recommended the subset of sams be rean listed to bridge the past and future. most importantly, though, the experts agreed that they generated previously, need to' adjusted for assay changes to avoid incorrect interpretation of the trends. in a study that our laboratory collaborated. last supper they released materials for 25 hydroxy d.
these materials improve the accuracy of measurements and compare ability of data across methods and laboratories. the question remains, as to wetter the materials also suitable to calibrate immunoassays. this will be in a study planned by the cdc. what are the lessons learned into the world of analytical methodologies that will help us move forward. p relatively small assay can have a large impact on levels and make interpretation difficult.
the best possible methodologies are needed to make sure changes can be detected while hard to sell, the accuracy of analytical methodologies should be supported. the validation of the method is currently under way and so is the bridging study for sams analyzed by different methods. these will be critical steps of 25 hydroxy d levels in the u.s. thank you, and our next speaker is dr. paul coates. >> good morning, i'm paul coates, i direct the nih office of dietary supplements.
by way of introduction i tell you where we came from. the dietary health act helped establish the office at the national institutes of health. our mission is strengthen knowledge and understanding of diet tear supplements to foster enhanced quality of life and health for the u.s. population. in doing that, we evaluate scientific information, we stimulate and support research, we disseminate the results of that research and ultimate goal is to educate the u.s. public.
what i wanted to do today was to tell you about our role in this. we've had a long interest in vitamin d as it has become recognized as a potentially important public health ipt venge. we've learned from cliff johnson's talk that vitamin did has assumed krkt status in discussions about risk for serious health conditions. there's clamor for more vitamin d intake, more and more call for people to have their vitamin d status monitored and measured.
they are not unreasonable goals, but we need to look more closely at the evidence for these relationships before we, as the government, make stronger recommendations about vitamin d for the general population. i'll try to address some of the scientific issues that are now being actively pursued as well as some of the key players who are involved. i wanted to tell you been an initiative called vitamin d initiative that coordinated, out of the office of diet tear
supplements but way more important than that, it involves partners from other dhs agencies, including, in addition to nih, cdc, and agency for health care research and quality, along with the national institute of standards and technology, department of defense, u.s. department of agriculture, and related agent circumstantial in canada. the goals of this partnership are to improve the measurement of vitamin d in foods and in dietary supplements, to improve the measurement of vitamin d status in haines and other
survey, as well as to identify and fill research gaps. to date, the outcomes have unincluded systematic reviews of relevant literature. publicly cams of recommendations of vitamin d status in n haines, and publication of reports, emanaing from a round table we held in nih in 2007. all of which we hope informs public policy. as you're aware, there's is considerable information about vitamin d in the literature, but also an awful lot of opinion,
sometimes based on a selective reading of that literature. we've adopted a systematic review of approach to addressing the relevant literature on vitamin d anden kroic disease conditions. we've done this in collaboration of our sister agency, a.r.c. which operates a network of evidence based on practice centers in the u.s. and canada to address challenging health reviews often used to inform public policy to develop clinical guideline, to inform insurance coverage decisions,
and in our case, to build research agendas. in recent year, ods, along with other partners in u.s. and canada produced two systematic reviews. the first is the evidence-based practice center and it focused on bone related issue. at that time, it was clear, most of the data has available for bone-related concerns. even in this case, a strong data related supplementation, to improve measures bone health in the elderly, there were
considerable gaps for other population groups. furthermore it was noted appropriately that the effect of vitamin d cannot be separated from that as kals up, since most studies, included a calcium supplement along with vitamin d. finally, it was not possible to say at what level of vitamin d status measured by serum 25 hydroxy vitamin d. what level could predict the risk of bone injury at least in adults. the second review which was conducted by tufts university's
evidence based center, extended the discussion to the role of vitamin d and other health conditions, and included a review of calcium and health as well. this review was specifically commissioned by the governments of u.s. and canada to inform the upcoming evaluation of dietary reference of the knew trents by the independent panel that cliff referred to earlier. briefly summarized here, extensive array of data, looking to the cause and effect question, of -- that most of us
are interested in, and it is -- summarizes a lot of data, suggesting that there is little effect documented to date, in most of those studies. i don't think we should take a message away that this means there is no effect, it simply call on us to look critically at the data that's currently available and expand the discussion to include additional studies. the irm review, as cliff noted, is under way, and is expected to report towards the -- in a three, four months or so.
i think a little later than dr. friedens suggested, new data. the challenges associated with this, are -- developing a better understanding of the relationship between exposure and effect. very likely, a cause of uncertainty in many previous studies, is the difficulty in actually measuring the exposure to vitamin d. as cliff noted. an important advance has been made with the ability to now
measure vitamin d exposure from all dietary sources, including diet tear supplements and food sources, but we still have challenges in measuring the proportion that comes from sun exposure. in general, while many observational studies have pointed to a strong relationship outcomes, there have been inconsistent findings from control trials as shown from the systematic reviews. finally, as noted by dr. pfeifer, problems in the
measurement of the vitamin d status and failure to under those problems may have led to incorrect interpretation of vitamin d status, especially in assessing trends over time. let me give you one example that we've been confronted with. there are clues, from eek logic studies, such as the one presented here, that point to a benefit of vitamin d, here in reducing the risk of colo-rectal cancer. this is an eek logical study that ends up with a summary statistic at the bottom.
diamondbacks suggesting that there's an improvement. odds ratio of about .7, when one compares low circulating levels of 25 hydroxy vitamin d. this has been documented for several other conditions as well. there have been very, very few clinical intervention studies related to cancer but the results of one of them are shown here. in this study that was published in 2007, older white women in
nebraska, were following for four year, in a randomized control trial, vitamin d and calcium. this incidents of all cancers after four years was scored. the reduction occurred in the frequency of cancers, in the red line compared to placebo and further reduction seen in the group to which vitamin d was added, leading to a rather impressive statistical analysis. the limitations of this study, though, included a couple of things, one is that cancer incidents was a secondary
outcome and no vitamin d arm was included in this study. however, the national cancer institute which funded this study in the first place has recently tubbed a same group to conduct a follow-up study, similarly designed but with additional arms, the results of which will be available in a few years. i want to tell you briefly about the women's health initiative. nih sponsored study that was the largest interventional study in history, recruited 160,000 most menopausal women to a variety of
study, over a 12-year period of time. 15-year period of time. here was an opportunity to exam the long-term effect of calcium and vitamin d supplementation. in a sub group of women who were studied for seven years to exam the potential effects on hip fractures. the results of this long-term study, the huge number of authors, indicated in the first slide, no significant effect on fractures occurred.
there was a 12% decrease across the population but it was not significant. the fracture rate decreased significantly among women who complied with supplement use. any important finding. of note, the last bullet, there's a significant increase in kidney stones in the women on vitamin d and calcium. this finding, i have to tell you, has been rarely reported elsewhere.
but needs to be volumed up. that's particularly the case as a result of this study. which, for me, points out another value of n. haines, the ability to coordinate data and exam trends and use them for clues for the development of future studies. here, 25 production of vitamin d level was in n. haines three. and individuals, were passively 2000. as expeexpected. the lowest cortile of 25 hydroxy level on the left, core spawns
to 18 nano grams, is associated with increased mortality. still, a nonsignificant increase in mortality, occurred at the highest levels of vitamin d. in other words a u-shaped curve. i don't want to overinterpret this. because these are not significant at the high end. it is clear from the confidence limits that data are scant at the right-hand end but the finding remains unexplained. we need to explain the biology of this finding, especially if
we recommend increases in vitamin d. and therefore shift the entire population to the right. i did want to give you some idea of ongoing research that's funded by the nih, it's not nih centric, it's what i know best. several institutes now funding the vital trial. vitamin d and omega 3 fatty acid trial to exam the role of vitamin d an omega 3 fatty acids in the primary prevention of cancer and cardiovascular dies. the national institute of aging and others are funding a dose
response study for vitamin d in the elderly. the kind of data much needed to inform diet tear intakes kinds discussions. providing the cancer study that provided provocative and useful findings. many institutes and centers in the nih are engaged in funding of intermediate year studies that help us under the metabolic fate and finally, joining forces to develop important analytical tools for the measurement of vitamin d status, including the
reference material and reference methods that dr. pfeifer referred to. finally, i wanted to give you a summary of the current recommendations that relate to vitamin d intake. you've seen the numbers of cliff before in the adequate intake to be incremental, 200 in the young, 400 in the intermediate age, 70 and above 600 international unit the per day. tolerable upper limit for all ages above one year of 2,000 international units per day.
how do people meet these recommendations? it's generally suggested that people can engage in some brief sun exposure, although there is no agreement among organizations about that, neither is there sun exposure would meet that need. it's a very complicated kind of question as we've come to learn. foods, especially those fortified with vitamin d remain a source of this important vitamin, that it turns out, as cliff's data showed, that in some populations, particularly
among the elderly, supplements are required. while we're waiting for the results of the ongoing review by the institute of medicine, other organizations have made recommendations, i've selected some here. they are by no means the only ones but the pediatric organizations of the united states and canada have recommended increased levels over the -- of intake over those recommended by the iom. the american academy of dermatology, recommends more
from supplements and none from -- not more from sun and in general, these organizations have also recommended target values for 25 hydroxy vitamin d. and while we think that the approach has merit, we're less certain about the actual target values and remain very excited about the possibility of learning more from the iom report. so, in closing then, this kind of summarizes a lot what the three of us have said.
we need the following, we need to continue monitoring the status of vitamin d in the population especially if there's any public health recommendation that might change the recommended intakes. we need more data on dose response relationships. we certainly need more data on basic research mechanisms and a lot of this will be driven by the existing and we hope ongoing partnerships that occur among agencies in the united states and canada, including the cdc, nih, udda and others including
health canada. thank you very much. on behalf of all of us. let me turn it back over to cliff who will moderate the next part of the session. [ applause ] >>> thank you, paul. we have approximately 15 minutes per question. so if anyone has questions, there are microphones in the
middle on each side. and that would be the preferred approach if you would like to come and ask a question. i'll ask a question. i'm trying to get the take-away message from the presentation, and i ma have it wrong, but it seems to me the take-away message is we're concerned about vitamin d insufficiency, across the population, particularly in certain sub groups. but then as i look at health effects, it's not clear to me
that we're actually experiencing changes in increased pref lens of ricketts or osteoporosis that i believe the major iom recommendations are set to pre vent. so one question is, okay, we have it -- we're insufficient, but how much of a public health problem do we really have. the second question, i wonder if you address the issues of cancer provincial, and if the intake recommended for cancer prevention is actually within the same range of exposure, or is it significantly higher than that recommended to prevent
osteoporosis and ricketts. >> the data that are being used to summarize these relationship, are not strong. they are not always of the highest value. and they don't always cover all of the questions that problem really need asking. given that there's uncertainty, there's an opportunity for people to take fairly strong stands on the basis of the available information.
there is a public health issue here. how strong it is remains unclear. people are not experiencing, to my knowledge, the kinds of increases in osteoporosis that might be attributable to shift in status. people are not experiencing the -- the shift in cancer incidents that might be associated with the shift. partly, because we're not certain that the shifts have actually taken place.
i think the data that christine and cliff both showed suggest that while some have concerns about a markedly downward slide in the vitamin d status of the population, we're not so certain that that's true. given that most of the data are eek logic, we have to under that they are confounded by a number of other things. i'm not saying that there isn't going to be a relationship, the fact is that at this stage, i don't know if there's a relationship and i'm anxious to see it played out.
>>. >> part of the problem that i think that you nicely articulated is the lack of a kree tier on-based standard for vitamin d efficiency. you alluded to population level outcome, cancer, osteoporosis, more tat. and i wonder if you could comment on which of those areas you think is most likely to produce a criterion-based standard or wetter there are some other functional tests like
the vitamin d, an in vitro assay to help which level is most appropriate for bone growth. >> i'm happy to try, bill. this is a difficult question. and it relates to some of the things that are on this slide that i forgot to turn off. the dose response relationships remain a serious lack in these and we don't have models for being able to explore those. it takes a long time to do the kinds of dose response
relationships in humans for chronic disease issue, and we probably need to develop or work with other kinds of study designs, including experimental models, at least to give us some clues. the only really -- the only real certainty that we have is that that 27.5 number, doesn't mean everybody has that disease and everybody below has not. it's been recognized that that's a clear relationship. beyond that, it becomes very difficult, because of the things
that we lacked. and i welcome any ideas in trying to decide how could be move forward better understanding the basic mechanisms and so on would be valuable. >>> i'm jim bueller. i have two questions. other than the bone effects, can you speak to the by logic plusability or pathways that vitamin d may be having on the effect of other conditions that you addressed and secondly, i
realize the focus of this talk is primarily on the united states, that has a global health issue in settings where nutritional deficiencies are severe and prevalent. are there any unique aspects, the issue of vitamin deficiency as a public health concern? >> i'm happy to try that one too. you ask all of the easy question, and i appreciate the chance to be able to answer them. the clues that we get about the by logic plusability of the role
of vitamin d in predisposing to other conditions beyond bone have to do with important observations, one is that vitamin d respecters are present on the universe of tissue, not just bone. so that provides a clue. that is all it does, unless you then take some of the next steps. vitamin d, of course, is a hormone, as well as being an essential nutrient, that complicates some of these
question, if you start to think about it as a hormone, then it having further effects, some of those are under active discussion at the moment. does it act as an anti-inflammatory, or does it promote anti-inflammatory kinds of responses. i -- is a possibility. there are clues there. but, at the moment, i think we are jumping a little bit from what we see in observational study, and making a leap or two.
maybe it's appropriate. maybe it's time. but i'm a geneticist by training and lab rat by training, i like to take an observation and take it two, three more steps to explore the mechanism before i'm prepared to really conclude that there is more than just a relationship here. in terms of global aspects, this is clearly an area where we have to get a better handle. there are various es pats that suggest that the global burden
of vitamin d deficiency, and that's a term of art, could be asp as a bill around the world. what is the number that's being used to define that? it's problem not 27.5. it's probably a number that's considerably higher than that. >> before we take another question from the audience, i would like to know if there's any questions from envision, real quickly? okay, hearing none, over here on the left.
>> brook steele, division of cancer prevention an control. a number of health care providers are testing their patients. are there questions that the patients should be asking of the providers? >> another -- may i? i'm placed to try, because this is something we think about all of the time. ours is an office of dietary supplements, a public health
intervention as a risk reducer, not a disease treater. of course, it doesn't matter what our office focuses on. the fact is that vitamin d questions are being asked in the public health environment, as well as in the medical management environment. there are a couple of things, i just learned, for example, a couple of days ago, that in canada, the ontario health assessment technology council, or advisory group, has made a recommendation to the ontario ministry of health that they
stopped paying for the routine measurement of 25 hydroxy vitamin d status, in the otherwise un -- unaffected population, there are circumstances where of course it's necessary. but this comes hard on the heels of their being very active an enthusiastic commitment and measurement in everybody and often. to monitor and track your status. because i don't know what to -- to tell people about what -- i
don't know what number to tell people to shoot for. oh, and i don't know that that number is reliably measured. it may be but i don't know that. i have difficulty in being able to make a very specific recommendation at this point. i think the advances that have been made by christine's laboratory, in harmonizing the measurement of 25 hydroxy vitamin d will go a long way to giving us the basic tool then the question becomes the one bill asked earlier, that's --
how do you know when you've reached a level that's relevant. so i'm sorry that at least from my point of view, i don't have a direct recommendation to make. >> i think we might have time for two more questions if they're short. i don't know, on this side on the right. >> i have a comment and a question. i focused my career in vitamin d, and the best time we didn't have the luxury of measuring vitamin d level.
we used calcium to phosphate ratio, an the level of alkaline phosphatase. my question is -- and these did change with vitamin d treatment. so my question is, is anybody attempting to look at simpler and -- simpler lead measures that affect vitamin d ma tap metabolism and hormone levels associated with vitamin d levels, are these looked at and then changed, and what is their specificity if the two measures not combined? >> yes.
a short answer. for us, for n. haines, we are only measuring the direct indicator. because it's really the best indicator to assess that. we're not looking at other indicators to assess the vitamin d. >> are they available? these people want to look at them? >> any, they are available in clinical as well as other
measures. >> my question is calcium levels and phosphate levels? >> yes, those are available and chemistry propel has the values as well. >> yes, some have been measured in various surveys. and standard bio chemistry profile, those are there as that's probably a good question we can talk about after the session is over. there's a lot of subtle parts we can go into.
in the essence of time, let's get the last question but we'll be happy to talk with you later. >> michael hollis new england journal of medicine shows deficienies 39 grams per nill. in my research i'm finding it to be around 20, 20 nano grams per nill, using lcms. using whi. i was wondering, what are your thought on this? >> this is an area of active interest in our own group.
chris sempos who is population scientist in our group recently published data, and addressing this issue about pth suppression is a good measure, maybe when you have full adequacy of vitamin d and number is under some discussion. it depends on what you look at. he's trying to, at this point, do some modeling to determine wetter there are ways in which you can look at this relationship in more detail. but i think in general, the number that you suggest, 20 nano
grams per mill, is the one that's been used for that purpose. >> so i think the questions you conceive, before i turn it back over to tanya, we're still in the state of lots of questions to be answered, we're all anxiously relating the iom report an i doubt the discussion will end after that report comes out. >> thank you all very much. and i'd like to point out that every time, in these sessions, i
find myself educated on the topic, and then on something special, so today, i learn from paul, that i'm not a senior citizen, that i fall into the intermediary category, and i like it much better than being a senior citizen. so i thank our speakers, thank you, the audience here and outside of cdc and invite you to join us in four weeks again.
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