to your HTML Add class="sortable" to any table you'd like to make sortable Click on the headers to sort Thanks to many, many people for contributions and suggestions. Licenced as X11: http://www.kryogenix.org/code/browser/licence.html This basically means: do what you want with it. */ var stIsIE = /*@cc_on!@*/false; sorttable = { init: function() { // quit if this function has already been called if (arguments.callee.done) return; // flag this function so we don't do the same thing twice arguments.callee.done = true; // kill the timer if (_timer) clearInterval(_timer); if (!document.createElement || !document.getElementsByTagName) return; sorttable.DATE_RE = /^(\d\d?)[\/\.-](\d\d?)[\/\.-]((\d\d)?\d\d)$/; forEach(document.getElementsByTagName('table'), function(table) { if (table.className.search(/\bsortable\b/) != -1) { sorttable.makeSortable(table); } }); }, makeSortable: function(table) { if (table.getElementsByTagName('thead').length == 0) { // table doesn't have a tHead. Since it should have, create one and // put the first table row in it. the = document.createElement('thead'); the.appendChild(table.rows[0]); table.insertBefore(the,table.firstChild); } // Safari doesn't support table.tHead, sigh if (table.tHead == null) table.tHead = table.getElementsByTagName('thead')[0]; if (table.tHead.rows.length != 1) return; // can't cope with two header rows // Sorttable v1 put rows with a class of "sortbottom" at the bottom (as // "total" rows, for example). This is B&R, since what you're supposed // to do is put them in a tfoot. So, if there are sortbottom rows, // for backwards compatibility, move them to tfoot (creating it if needed). sortbottomrows = []; for (var i=0; i
Could the disparity between the life expectancies of the black and white population of the United States be largely accounted for by the greater incidence of Vitamin D deficiency within the black population? And would addressing this vitamin deficiency in the black population erase the gap in racial life expectancies?
We would hypothesize that the answer to both questions is yes, and we would caution that it's not quite as simple as it sounds.
To understand why, we'll take a closer look at Vitamin D's role in the human body, how it applies to the chronic diseases that disproportionately affect the black population of the U.S., and how the greater incidence of the deficiency among the black population would appear to account for the unusual features we've observed in the percentage of survivors of the black population for each 100,000 born alive. We'll also explain why the steps the U.S. government has instituted in mandating the fortification of dairy products with Vitamin D would appear to be largely ineffective for the adult African American population and ultimately discuss how the deficiency can be addressed more effectively.
The primary role of Vitamin D in the body is to help regulate the level of calcium in the bloodstream. It does this by facilitating the absorption of calcium from dietary sources in the digestive system and by promoting normal bone growth and mineralization. As the tuberculosis study we've previously cited demonstrates, Vitamin D also plays a key role in facilitating the production of cathelicidin, an antimicrobial peptide that play a vital role in the immune system's ability to resist infectious diseases.
Vitamin D may be obtained from two key sources. The first is from natural sunlight exposure, where ultraviolet rays (UV-B) penetrate into the skin and is synthesized through natural biochemical reactions. The second is from foods or dietary supplements that either contain or have been fortified with Vitamin D. Like Vitamin B, there are several different kinds of Vitamin D. Sunlight exposure creates Vitamin D3, while many food supplements contain Vitamin D2 or D3. The most recommended form for dietary supplementation is Vitamin D3.
For adults between the ages of 19 and 50 years old, the U.S. Food Nutrition Board recommends a daily Vitamin D intake from food or dietary supplements of 200 IU (International Units), which is equivalent to 5 mcg (micrograms). The American Academy of Pediatrics will be publishing new guidelines for Vitamin D intake this fall, which will recommend that infants, children and adolescents should receive 400 IU (or 10 mcg) This same level is recommended by the Food Nutrition Board for people Age 51-70 years old. People over the age of 70 are recommended to take in 600 IU (or 15 mcg).
These levels are recommended as the level of ultraviolet light exposure that individuals receive on their skin from direct sunlight is difficult to anticipate and varies by prevailing weather conditions and geographic latitude, with people living in northern latitudes especially disadvantaged. Other factors, such as clothing, sunblock application and the amount of melanin skin pigmentation by individual also negatively affect the level of Vitamin D production from UV-B exposure.
It is possible to overdose on Vitamin D dietary supplements. Ingesting more than 2000 IU (50 mcg) a day on a sustained basis may produce a toxic effect, initially indicated by nausea, but possibly leading to kidney damage, kidney stones, muscle weakness or excessive bleeding. Higher amounts may be taken without negative impact for limited periods of time.
With higher levels of melanin in their skin, which absorbs high quantities of the UV-B radiation that stimulates natural Vitamin D production, the black population of the United States is much more likely than the white population to suffer the effects of Vitamin D deficiency, as well as the very closely related conditions associated with calcium levels, which Vitamin D regulates within the body.
In the table below, we've outlined the chronic diseases and health conditions that disproportionately affect the black population, above and beyond those already well-linked to Vitamin D or calcium deficiency, and linked to research supporting the connection if one has been established.
Chronic Diseases Linked with Incidence of Vitamin D Deficiency | ||
---|---|---|
Category | Chronic Disease or Condition | Linked to Vitamin D Deficency? |
Infant Mortality | Premature Birth/Pre-eclampsia | Yes |
Low Birth Weight | Yes | |
Heart Disease | Cardiovascular Disease | Yes |
Cancer | Breast Cancer | Yes |
Lung Cancer | No | |
Colorectal Cancer | Yes | |
Cerebrovascular Disease | Hypertension | Yes |
Atherosclerosis | Potentially | |
Infectious Diseases and Conditions | HIV/AIDS | No |
Tuberculosis | Yes | |
Septicemia | Unknown | |
Kidney Disease | Yes | |
Negative Health Contributors | Overweight and Obesity | Yes |
Diabetes | Yes |
We observe that the increased incidence of Vitamin D deficiency among African Americans would appear to contribute to the increased incidence of the chronic conditions that negatively affects the health the black population of the United States, which in turn shortens their longevity with respect to that of the white population.
Now that we've identified the chronic diseases that act to disproportionately shorten the lives of the black population of the United States and confirmed that a deficiency of Vitamin D is a major contributing factor to nearly all of them, let's look again at our chart showing the difference in the percentage of survivors of every 100,000 born between the white and black population of the United States as we begin to hypothesize on why the disparities between races exists:
The grand hypothesis we're going to offer is that a deficiency of Vitamin D within the black population accounts for nearly all of the difference observed between the black and white population. Let's take a closer look to see how that might work:
We promised at the beginning that we'd figure out how to bring cattle herding into the picture, and here it is: the vast majority of the black population of the United States is descended from the peoples of western sub-Saharan Africa and, as a result, become lactose intolerant as they grow into adulthood as their genetic makeup doesn't permit the digestion of dairy products.
Not all peoples of African descent are in that boat. The peoples of eastern Africa do have the ability to digest milk products. The difference between each comes down to a genetic adaptation that takes hundreds of generations to develop that coincides with the practice of cattle herding. The peoples of eastern Africa have a very long history of cattle domestication, beginning anywhere from 3,000 to 7,000 years ago. By contrast, the peoples of western Africa have a much shorter history with herding cattle and haven't developed a similar genetic adaptation.
And that's why the U.S. government's mandated fortification of dairy products with Vitamin D doesn't work for the adult black population! Except perhaps for black immigrants from eastern Africa, which may account for part of the observed greater life expectancy of foreign-born black immigrants to the U.S.
There are very few foods that naturally contain Vitamin D. The non-fortified dairy product portion of the menu includes items like: cod liver oil, salmon, mackerel, tuna, sardines, margerine, whole eggs, and beef liver. We know - except maybe for salmon, tuna, eggs and margerine, it's hard to look at that list and keep yourself from salivating! (Mmmm, cod liver oil....)
More seriously, there a number of ready-to-eat breakfast cereals are fortified with Vitamin D, which we would recommend be eaten as a dry snack. There are, of course, direct alternatives to dairy products. Of these, our first choice to see if it works would be those dairy products that have been formulated to accommodate those who are lactose intolerant. Other milk-substitutes such as soy milk (are you salivating again?) might work out, but we'll observe that it would work better for women than it would for men.
Meanwhile, there are always Vitamin D tablets. A quick trip to our local supermarket showed a 90-day supply of 400 IU Vitamin D tablets would cost about $4.00 (USD), which means that a year's supply for an individual might be purchased for anywhere from $12-$20 (USD) taking into account competition between stores, sale vs. non-sale prices, availability, etc.
All in all, a super-cheap way to potentially, and quite literally, add years to your life.
The trick would be to find what you wouldn't mind eating or consuming on a regular basis and go with it. Sooner or later, food producers will introduce improved, better tasting products that can meet the specific dietary needs of the black population.
Often, the toughest questions to answer are those that ask "why this, but why not this?"
Throughout this series of posts, that's been our challenge. Why do African Americans have higher infant mortality than whites, but then have a nearly equivalent todder-child-teenager mortality rates? Why do blacks then have a higher adult mortality rate, but then substantially lesser mortality for those over the age of 80 than the white population of the United States? Why do urban blacks, who have significantly greater access to health care facilities than their rural peers, have much lower life expectancies? Why are black teenage mothers less likely than older mothers to give birth either prematurely or to low birth weight babies, the leading cause of infant mortality? Why do black immigrants who statistics indicate would live much shorter lives in their native countries live longer than native-born African Americans if they immigrate to the U.S.?
To answer these questions, we asked and answered several of our own. What health conditions account for the disproportionate mortality of African Americans compared to whites at every stage of life? What factor or factors contribute to these disproportionate outcomes that might also answer "why this, but not this?"
That's how we came to this final post in this series, in which we've presented a single, unifying explanation that potentially accounts for what we observe in all the data we have and leads to our seemingly simple solution. In doing all this, we've linked to cutting edge medical research and breaking news covering some of the latest findings in genetic anthropology, spanning several millenniums of human history in the process.
And we have to note, it might not pan out as we see it. That's where we're at today, awaiting the results of scientific studies and research that confirms or rejects what we've hypothesized.
But we have to admit, it would be pretty cool if we turn out to be right!
For reference, here are all of the posts in the series:
The post that started the whole thing! We were surprised to find that blacks over the age of 80 had longer remaining life expectancies than whites of the same ages in the U.S. We also used the opportunity to ridicule some pretty blatant rent-seeking behavior on the part of researchers seeking funding for their work.
We revisited the life expectancy figures between blacks and whites and took a closer look at the underlying data, which allowed us to reject racism as an explanation for what we observed. We also began asking "why this, but not this?" in comparing not just the survivorship of the black and white populations of the United States, but urban vs rural blacks, immigrant vs native-born blacks, and the effect of older vs younger mothers for African American infant mortality.
You can't address racial disparities in life expectancies unless you know what chronic health conditions disproportionately affect the black population of the United States compared to other racial or ethic groups.
Chronic diseases often have a very strong genetic or heredity component in determining who is vulnerable to them. In this post, we explored the idea that what doesn't kill you either softens you up for what will or makes you more vulnerable to other health hazards in comparing the black population of the United States to sub-Saharan Africans who share much the same genetic anthropology, while also discovering very recent research whose results potentially explain why all peoples of African descent are more vulnerable to the things that disproportionately kill African Americans.
Does a chronic vitamin deficiency explain why the disparities between black and white life expectancies in the U.S.? We explore this possibility and why it may not as easy to address as you might think on first glance, as well as how individual African Americans might do so successfully.
Update 18 August 2008: Added conclusion and reference links for series!
Labels: africa, health, health care, medicine
Welcome to the blogosphere's toolchest! Here, unlike other blogs dedicated to analyzing current events, we create easy-to-use, simple tools to do the math related to them so you can get in on the action too! If you would like to learn more about these tools, or if you would like to contribute ideas to develop for this blog, please e-mail us at:
ironman at politicalcalculations
Thanks in advance!
Closing values for previous trading day.
This site is primarily powered by:
The tools on this site are built using JavaScript. If you would like to learn more, one of the best free resources on the web is available at W3Schools.com.