Measles vaccination rates in Southern Alberta by region

Here’s a graphic from Alberta Health on vaccination rates in southern Alberta for measles by town and region.

Note that anything <80% creates conditions for a sustained epidemic. The AHS goal is 98% coverage, which is about what is needed for herd immunity to keep any cases from developing.

Note too that metro Lethbridge (due north of Spring Coulee, in the approx centre of the map) is in the 80-90% range, and yet that is where the outbreak began and is persisting for the moment. So 80-90% doesn’t cut it.

Measles Coverage 2013

And, a second slide gives some of the complications that attend the illness.

They don’t mention SSPE, which can afflict the brains of measles patients even decades later.

Measles Complications

Advertisements

Is Popeye More Likely to Respond to Vaccination?

(or, Why blaming nutrition is not your anti-vax get-out-of-jail-free card)

In Southern Alberta, we are currently in the midst of a measles outbreak.

Some have asked me recently about the claim that better nutrition would lead to better vaccine response.

The purpose of this claim seems to be an attempt to disprove concerns about herd immunity.

Background

No vaccine is 100% effective. Those who do not respond to the vaccine, and patients that are too young to be vaccinated, depend upon herd immunity for protection—measles (or other infectious diseases) can’t get established in a population unless there is a certain percentage of vulnerable people.

So, when those who through bad science or their own philosophy reject vaccination, they increase the risks to everyone. If you don’t want to get a tetanus vaccine, fine—the only person you’ll kill or cripple is yourself.

One dose of measles vaccine is typically 95% effective. A second booster can get that to 98-99%. But, it ain’t 100%. Bluntly, if you forgo things like measles vaccines, you put me and my kids at risk. You also put kids with leukemia, and patients with HIV, and newborns too young to be vaccinated, and a variety of others at risk too.

(89% of patients in the USA in 2011 who got measles had not been vaccinated. But, 11% who got it had been. Thanks a lot.)

Blame the victims

Now, this seems like a pretty crumby thing to do—and it is. So, some are now claiming that they aren’t really putting your kids at risk, because vaccines work better if you have better nutrition. The subtext is clear—if you get the measles vaccine and you don’t respond to it, it’s your own darn fault for eating such a lousy diet, or not taking some vitamin supplement, or whatever. (If they go a step further and try to sell you the supplement, run away.)

We are supposed, then, to blame the lousy diet of people who do get vaccinated, and not the irrational and scientifically unsupportable decision of the vast majority of those who choose not to vaccinate.

This might be a compelling argument—if it were true. But it isn’t.

The First World and the Third World

It’s always a bit dubious when people start bemoaning poor nutritional status in North America. If anything, we eat too many calories and the like; we do not typically have a problem with macro- or micro-nutrient status (with some subgroups being exceptions, which I shan’t go into here).

But, for the sake of argument, let’s follow the claim, and see where it leads.

If poor nutrition was a significant factor in vaccine non-responders, that would be an important thing to know. Why? Well, for starters, when we give vaccines in the Third World, those people are at much higher risk of malnutrition, poor vitamin status, and all the rest than anyone in the First World would ever be in their worst nightmares. So, if nutrition is a factor in measles vaccine response, we ought to be able to detect that in the Third World especially. We’d like to know, because maybe it would be better to give them some vitamins or better nutrition, and then vaccinate them later. (A similar analysis could be and has been conducted for a variety of vaccines; I will focus on measles because it is the one in the news right now.)

If you go way back to 1980, this question was looked at for smallpox and measles. The conclusion:

 Malnutrition did not affect the children’s ability to develop adequate immune response to measles o[r] smallpox vaccine, and there were no major complications during the 8-week period of follow-up. Since measles is a very severe disease, which in malnourished children can carry a case fatality rate as high as 50%, malnutrition should be a prime indication for measles immunization, and certainly not a contraindication.[1]

No effect—and many of these kids were severely malnourished.

Is 1980 too long ago? Well, here’s one from August of 2013.

It looks at kids who are both malnourished and have potentially disastrous risk factor: kids with HIV+ mothers. This is a randomized, placebo-controlled trial that gave some kids vitamin supplementation prior to measles vaccination.

The stage of the mother’s HIV affected how well the kids’ immune system responded—more advanced HIV made it more likely for the children to respond. But, what about the “nutrition” that we’re assured is so important?

There were no effects of infant multivitamin supplementation on measles seroconversion proportions, IgG concentrations, or IgG avidity. [2]

Translation: Seroconversion means developing protective antibodies; IgG concentration is how much antibody; IgG avidity is how well the antibody binds to measles.

Long story short—giving the kids vitamins made no difference at all to the vaccine responses, and they’re from Tanzania.

Are we really expected to believe that a kid in North America—no matter how lousy his or her diet—is in worse nutritional shape than a child born to an HIV+ mother in Tanzania?[3] Well, anti-vaccination activists have asked us to accept bigger whoppers than that, so I guess we shouldn’t be surprised.

An ironic risk—would supplements be risky?

Ironically, the public health worry about malnutrition and supplementation has been whether supplementation might worsen the measles vaccine response rate. It would be great to give all the kids you saw in your third world vaccination clinic Vitamin A—this has been shown to be cost effective, and they need it. It’s hard to get them into the clinics; they have to travel a long ways sometimes, and wait a long time. How great would it be to do both at once, if you can? But, what if doing one makes the other less effective? This actually might have happened when some six month old kids were vaccinated. (They were vaccinated early—but, this is a scary prospect, if true.)

Well, this has been looked at—happily, there is no concern so far.

Overall, the seroconversion rates did not differ between vitamin A (89.5%) and placebo (87.6%) groups. There were no significant differences in the geometric mean titers in the two groups (ratio of geometric means, 1.19; 95% confidence interval, 0.97–1.46). Among malnourished infants, the geometric mean titer was significantly greater in the vitamin A group compared to the placebo group (ratio of geometric means, 1.57; 95% confidence interval, 1.18–2.0), but seroconversion rates did not differ. There were no differences in seroconversion rates and geometric mean titers in the two study groups among the well-nourished children. These results indicate that 30 mg vitamin A does not reduce the immune response to the coadministered vaccine and, therefore, can be continued to be given safely in public health programs (emphasis added).[4]

Note that antibody levels were slightly lower in malnourished kids—but, there was no statistical difference between malnourished or well-nourished children in whether they’d have measles immunity or not.

But, it’s ironic that the thing that worried real vaccine scientists is the exact opposite of what the North American anti-vax nutrition pushers claim—the worry was that supplementation in people who were truly malnourished might actually decrease the vaccine’s effectiveness. It certainly didn’t increase it.

Big Picture

Am I, perhaps, merely cherry-picking studies? Am I just finding a few that support my position, while ignoring the others?

A fair question. Fortunately, someone recently did an extensive analysis of all vaccines and all the data on nutrition status and response to those vaccines. (This was done for the Bill and Melinda Gates Foundation, which was founded by the Microsoft billionaire and his wife. They do really good work, and it is intensely data-driven.)

This review was published in 2009, and full text is available.[5] Here’s some measles-related highlights (emphasis added in all cases):

  • “Our analysis indicates that malnutrition has surprisingly little or no effect on vaccine responses.”
  • Protein-energy malnutrition “studies did not show any association between malnutrition and the immune response to M[easles] Vaccine.”
  • A few studies did show that children with kwashiorkor (severe, starvation-level protein lack in the diet—there are very disturbing pictures here if you want to see how bad we’re talking) had lower responses to measles vaccine. But, some of these studies only waited two weeks to see if there was a response—in other studies of kwashiorkor, malnourished children delayed their response to the vaccine, but by three weeks had, like the well-nourished, a good response.
  • Young children (6 months) given Vitamin A [VA or Vitamin A supplementation=VAS] have lower response rates, but only if they have high levels of antibodies from their mothers. “Moreover, a clinical trial in Bangladesh assessed the effect of VA supplements on M[easles] V[accine] response when administered near to vaccination or not. VAS administered within 4 wk before or 2 wk after measles vaccination was not associated with altered vaccine failure rate compared with administration of VA outside these time limits.” In sum, “although mean antibody titers tended to be higher in participants who received VA, seronconversion rates were universally high and did not significantly differ between supplemented and unsupplemented participants.”
  • Data on iron deficiency is poor, but “children with iron deficiency anemia seem to have intact antibody responses to vaccination. Although iron deficiency is known to affect T lymphocytes, the antibody response is preserved, even when it requires help from T h[elper] cells.” Likewise for Vitamin D, “there is no evidence that vitamin D has any effect on vaccine response,” though the data is very sparse.
  • Zinc supplementation may affect cholera vaccine response, but not “BCG, diphtheria and tetanus toxoids, rabies, influenza, and pneumococcal vaccines.” Measles has not been looked at at all.
  • “We found occasional evidence of marginal effects of micronutrients, but the evidence base is very limited and frequently contradictory.” It is hard to see how these type of effects, which can barely be discerned (if they exist at all) in Third World populations could make much of a difference in North America.

Summing up the data

The authors frequently return to the fact that there isn’t a ton of data on this topic—which should tell us that if they don’t know, then the confident assertions of those in North America who claim that “studies show” that nutrition is a big factor in First World vaccine failures are talking out of their hat. Thus, far, we can barely find any evidence in the Third World in horrendous circumstances:

Surprisingly, we found little convincing evidence to indicate that current nutritional status or coadministration of nutrient supplements has clinically important effects on vaccine efficacy.

To claim that the non-responders have only their poor diet to blame if they get measles—instead of what is essentially a superstitious or pseudoscientific decision of non-vaccinators to forgo vaccination—just isn’t supported by the facts.

So, why do some people not respond to vaccines?

This is an active area of research. There’s a very interesting bit of data out of Israel that compared desert Bedouin Arab responses to measles vaccine versus Israeli Jewish children.[6]

This is interesting for two reasons:

  1. From a nutrition standpoints, the Bedouins are at a disadvantage—they have much larger families (9 children on average), live in crowded, relatively unsanitary conditions, have many more infections, and almost certainly have a lower standard of living and access to much less robust food supplies.
  2. Genetically, the two populations are different.

Intriguingly, the Bedouin had a 99% conversion rate, while the Jewish group had only a 79% response—astonishingly low. This was not a one-time fluke either—a previous study of Jewish children had likewise 24% not respond to the vaccine, despite having evidence they were vaccinated.

This sort of thing isn’t confined to the Middle East. Studies have observed:

  • First Nations people responding better than Caucasian Canadians;
  • East Indians responding better than Africans;
  • Twin studies show that identical twins have a higher rate of vaccine failure if one twin fails.

You see where this is headed—vaccine response depends, at least in part, upon genetic factors. The mechanisms for this are just beginning to be explored, but they have to do with mutations to the receptors. Some mutations improve your response, and others decrease it.

So, a large part of whether you respond is simply a genetic luck of the draw. We can’t eat our way out of it.

Bottom line

So, if you’re not going to vaccinate yourself or your kids, please—at least be honest about the facts. You’re putting them at risk. But, you’re also putting the rest of us at risk too.

It isn’t because we wouldn’t eat our spinach.

It’s because we are unwise enough to have 60% vaccine coverage, in a disease that needs at least 80% to prevent epidemic spread.

Learn more

For information about measles , go here.

If you think you or someone may have measles, do not go to the ER. Do not go to the doctor’s clinic. Do not go out in public.

If you live in Alberta, call this number, and do what they tell you: 1-866-408-5465.

Third world skepticism


[1] AE Ifekwunigwe, N Grasset, R Glass, S Foster, “Immune responses to measles and smallpox vaccinations in malnourished children,” Am J Clin Nutr 33/3 (March 1980) :621–4.

[2] Christopher R. Sudfeld, “Effect of Multivitamin Supplementation on Measles Vaccine Response among HIV-Exposed Uninfected Tanzanian Infants,” Clin Vaccine Immunol 20/8 (August 2013): 1123-1132.

[3] Recall that having HIV+ mother doesn’t just expose the child to risk of infection—such women are less likely to be well, are less able to work, will probably make less money in a country not known for high-riding lifestyles, and are less able to provide food for the baby, etc. You’re at risk in this situation.

[4] Rajiv Bahl et al., Vitamin A Administered with Measles Vaccine to Nine-Month-Old Infants Does Not Reduce Vaccine Immunogenicity,” The Journal of Nutrition 129/8 (August 1999): 1569–1573.

[5] Mathilde Savy et al., “Landscape Analysis of Interactions between Nutrition and Vaccine Responses in Children,” The Journal of Nutrition 139/11 (November 2009): 21545–22185.

[6] Bracha Rager-Zisman, et al.¸Differential Immune Responses to Primary Measles-Mumps-Rubella Vaccination in Israeli Children,” Clin Diagn Lab Immunol 11/5 (September 2004): 913–918.

A delicensed heart surgeon misleads you about what causes heart disease

There is another strange medical thing making the Internet rounds again.

People are asking me what I think, so I will tell them, and anyone else who cares.

These are useful things to review not because they are particularly sophisticated bits of media (they aren’t) but because we can learn things about how to assess such material for ourselves.

The first is called “Heart surgeon speaks out on what really causes heart disease.” I’m going to address this according to the various rhetorical tricks or tactics that the article uses, which is authored by a Dr. Luddell.

Right off the top, consider the source. The same webpage tells us that “Strong evidence links vaccines to autism.” As readers of this on-line rag have learned before, this is fear-mongering nonsense. Such evidence simply does not exist. Anyone who claims it does is either misinformed, lying, or incapable of assessing scientific evidence.

But, leaving that aside, let’s consider the arguments and tactics.

Continue reading

Vaccines and breastfeeding

I occasionally meet parents who have decided to delay vaccinating their newborn.

Such parents have usually been alarmed by false claims about the risks of vaccines to children, which I have discussed earlier.

Another common worry is that children are “too small” for such vaccines. This simply isn’t true. Vaccines are timed for when a child’s immune systems will respond to them. This is why, for example, polio vaccines are given beginning at age 2 months, while measles waits for 1 year of age—a two-month-old won’t respond properly to a measles vaccine, but will to polio. (Getting such vaccines too soon wouldn’t be dangerous, but it wouldn’t generate an immune response, so there’s no point.)

Parents of unvaccinated children sometimes comfort themselves with the thought that since they are breastfeeding, this provides adequate protection. After all, there are antibodies against disease in breast milk, right?

Breastfeeding is certainly the ideal choice for the vast majority of newborns and their parents. (There are a few diseases or conditions for which you shouldn’t breast feed, and a few drugs that a mother might have to take that would be dangerous to an infant.)

It is also true that antibodies from the mother are passed in breast milk to the baby. But, parents often don’t know what kind of antibodies, and what kind of protection they provide.

And, that’s the rub, as they say.

The Children’s Hospital of Philadelphia has a Vaccine Education Center. Their statement is important:

Sometimes parents wonder whether they can forego immunizations for their baby because the baby is being breastfed; however, this is not the safest decision because antibodies in human breast milk bathe the intestinal surface but are not absorbed. Therefore, breast milk antibodies never enter the lymphatics or circulation where they would be needed to protect against diseases for which infection in the blood (circulation) is an important part of how viruses and bacteria cause disease. Examples of these types of diseases include diphtheria, tetanus, pertussis, measles, mumps, rubella, varicella (chickenpox), pneumococcus, Haemophilus influenzae type b, polio, hepatitis A and hepatitis B.

Antibodies in breast milk enter the baby’s gut. These antibodies are useful, but their only function is to prevent the baby’s gut from absorbing dangerous infections. So, breast milk antibodies are a great way to help prevent things like diarrheal illnesses. That’s no small thing—in the third world, diarrheal illness still kill millions of children every year. (Even in the US, hundreds still die every year from diarrhea.)

So, before modern sanitation and germ theory, breast milk antibodies could mean the difference between a child living and dying, and still does in the third world. (This is one reason why efforts of baby formula companies to convince third world mothers not to breast feed are so pernicious.)

But, breast milk antibodies do not enter the baby’s blood stream or lymphatic system. They stay in the gut. So, breast milk antibodies are completely powerless to fight any infection that enters a baby by any other route—for example: by the lungs, by a scratch on the skin, and so forth.

So, antibodies in breast milk might protect your baby from stomach flu—but, they won’t protect him or her from some of the worst diseases known, including:

  • tetanus (lock jaw)
  • polio
  • hepatitis A and B
  • pertussis (whooping cough)
  • measles
  • mumps
  • rubella (German measles)
  • diphtheria
  • pneumococcus (causes severe pneumonia).
  • H. influenza, type b (causes potential fatal airway compromise)

It is a sad irony that parents worry that their baby’s immune system “can’t handle” vaccinations. It can, easily.

But, their immune systems can’t handle all the above diseases very well at all—newborns are at greatest risk of death or life-long problems from these diseases in the event of an outbreak. This is because of a less well-developed immune system, and the fact that they are smaller.

A baby’s best lines of defense are:

  1. vaccination for themselves; and
  2. herd immunity from a well-vaccinated population for those diseases for which they are too young to mount a proper response.

Once again, your choices don’t just affect you—they affect my kids too. We all need that herd immunity.

Here’s hoping people will use science, and not fear, in making these decisions.

So, doc, should I take vitamins?

People often get told they should take vitamins for the health, or to feel better. People often take vitamin supplements. Much less often, they ask me if they should take vitamins.

As is often the case, the answer to this question isn’t a simple yes or no answer.

Note that everything I say here presumes at least two things:

  • the patient lives in the developed world and has a reasonably healthy, balanced diet.
  • the patient is healthy and does not have a specific disease that either requires supplementation or for which supplementation could cause problems. Check with your doctor about your own situation.

I have included links to reliable websites for further information, recommended doses, etc.

Part 1 – Worthwhile supplementation

Folic acid

There is substantial evidence that women of childbearing age should take folic acid. This reduces the development of neural tube defects (e.g., spina bifida) and cleft lip/palate. There is the most benefit if the mother-to-be is taking the folic acid before she conceives. So, if you are sexually active and aren’t using birth control, taking folic acid is a good practice.

Vitamin D

For people in northern latitudes, like Alberta, we often lack adequate sunshine, which is necessary for the body’s synthesis of Vitamin D.

Vitamin D deficiency can be detected by lab testing, but given that it is a relatively common problem in Alberta, it isn’t recommended routinely. You can just take supplementation. Milk is supplemented with it, but people who don’t eat a lot of dairy may need other sources, including supplementation.

Calcium

Women’s peak bone mass is at about age 25; adequate calcium intake is necessary to prevent problems later in like life osteoporosis and fragility fractures. As patients age, they may also benefit from supplementation to make sure they reach proper calcium targets. There’s also some evidence for endometrial cancer prevention.

Iron

Iron supplementation may be needed for people if they have low iron. This is a bit of an exception to the “healthy patient” rule I pointed out above. Women who menstruate are most at risk. Once you are iron deficient, it is essentially impossible to eat enough iron from food sources to catch up, so you will be anemic forever without supplementation.

Summary: Aside from these relatively few exceptions, there is very little evidence for help using vitamin supplementation in healthy, well-nourished populations. We explore a few of the details in the next section.

Part 2 – Cases in which supplementation has not shown any effect

  • A recent (2013) meta-analysis of multi-vitamin and multi-mineral supplements showed no change in death rates with supplementation.[1]
  • Vitamin supplementation did not affect all-cause mortality, cancer rate, or cardiovascular disease in the Women’s Health Study: “the study provided convincing evidence that multivitamin use has little or no influence on the risk of common cancers, cardiovascular disease, or total mortality in postmenopausal women.”[2]
  • No change in cancer rate for women over age 40 taking B6, B12, and folic acid.[3]
  • No change in cancer rate for men using Vitamin E, Vitamin C, or a daily multivitamin.[4]
  • Vitamin E had no effect on rates of heart attack, while taking daily aspirin did.[5]
  • Vitamin C has no effect on whether you catch the common cold. It may shorten the duration of symptoms slightly, but the effect is so slight that it probably doesn’t have much to notice or use in clinical practice.[6] (This was an analysis of 30 trials containing 11,350 people.)
  • Vitamins A, C, beta-carotene, selenium (all are anti-oxidants) and folic acid, B6, and B12 are all shown no influence on the progression of coronary artery disease.[7]

Part 3 – Cases in which supplementation has been shown to cause harm

In randomized controlled trials, the following harmful effects have been observed:

  • Patients taking cholesterol-lowering drugs alone had lower risks of heart attack and a decrease in clogged arteries compared to patients taking such drugs with Vitamins E, C, beta-carotene, and selenium (all anti-oxidants). Thus, the anti-oxidants likely blocked some of the benefit of these medications.[8]
  • Use of Vitamin E supplementation (400 IU) showed a 17% increase in prostate cancer.[9] Combining selenium with Vitamin E showed no change in cancer rates.[10]
  • Use of Vitamin E raised the risk of hemorrhagic stroke (bleeding) by 22%, while decreasing the risk for embolic (small clot) stroke by 10% in a set of 118,765 patients.
    • This equals one bleeding stroke for every 1,250 people taking vitamin E, and prevention of one clot-based stroke every 476 people.
    • Bleeding is usually far more serious, and causes worse outcomes, so Vitamin E is probably a bad bet on balance.[11]
    • High vitamin A use linked to higher hip fractures in women.[12]
  • Using Vitamin C and E in women with coronary artery disease resulted in higher rates of both death and non-fatal heart attack.[13]
  • Women with kidney disease from diabetes had higher rates of heart attack, continuing kidney failure, and stroke when taking folic acid, vitamin B6, and vitamin B12.[14]
    • This was despite a lower homocysteine level (which has a link to cardiovascular disease). Thus the supposed protective effect of lower homocysteine (if any) was outweighed by some other factor(s).
  • Use of Vitamin C supplementation showed a rise in the risk of cataracts in women (no men were studied in this trial).[15]
  • Vitamin supplementation may increase the risk of breast cancer in women.[16]

Conclusions

The Medical Letter on Drugs and Therapeutics is a well-regarded resource. They accept no advertising, and are strictly evidence-based. Their conclusion in 2005 for recommendations included:

  • Folic acid supplementation, with possible addition of Vit D and B12 in the elderly [I would add that northern latitudes like Canada should probably think about Vit D for all members of the population.]
  • Vitamin C shows no evidence for prevention of any disease.
  • Beta-carotene should not be supplemented.
  • Women should avoid Vitamin A supplementation during pregnancy and after menopause.
  • Balanced diets are probably better than supplementation.[17]

One editorial hoped that

the exuberant use of vitamin-mineral supplements may be tempered by such findings, which carefully separate facts from faith.[18]

One can hope. But, people who sell and push supplements have a vested interest in continuing to sell their wares. And we are often inclined to think, “Well, at least it can’t hurt.” But, we must remember that taking anything with possible good effects opens us up to possible bad effects.

There is an irony too in that doctors are sometimes accused of being “pill pushers,” but then get in trouble when we encourage people to get their nutrients from a healthy, balanced diet (which has shown benefits for things like cancer and heart disease) rather than just popping a pill.

But, now you at least know why your doctor probably isn’t advising you to take much by way of vitamin supplements if you’re healthy—there is a lot of evidence, on hundreds of thousands of patients in randomized placebo-controlled trials, that shows that it simply doesn’t help. And, sometimes it can harm.

Caveat emptor—let the buyer beware.

Useful links


[1] Helen Macpherson et al., “Multivitamin-multimineral supplementation and mortality: a meta-analysis of randomized controlled trials,” American Journal of Clinical Nutrition 97/2 (February 2013): 437-444.

[2] ML Neuhauser, “Multivitamin use and risk of cancer and cardiovascular disease in the Women’s Health Initiative cohorts,” Archives of Internal Medicine 169 (2009):294-304.

[4] J Muntwyler et al., “Vitamin supplement use in a low-risk population of US male physicians and subsequent cardiovascular mortality,” Archives of Internal Medicine 162 (2002):1472-1476.

[6]  RM Douglas et al., “Vitamin C for preventing and treating the common cold,” Cochrane Database of Systematic Reviews 2007, Issue 3. Art. No.: CD000980.

[7] J Bleys et al., “Vitamin-mineral supplementation and the progression of atherosclerosis: A meta-analysis of randomized, controlled trials,”  American Journal of Clinical Nutrition 84 (2006):880-887.

[8] [BG Brown, “Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease,” New England Journal of Medicine 345 (2001): 1583-1592.

[10]Review of prostate cancer prevention study shows no benefit for use of selenium and vitamin E supplements,” (27 October 2008) NCI news release.

[12] D Feskanich and others, “Vitamin A intake and hip fractures among postmenopausal women,” JAMA 287 (2002):47-54.

[14] AA House et al., “Effect of B-vitamin on progression of diabetic nephropathy,” JAMA (2010) 303:1603-1609.

[15] S Rautiainen et al., “Vitamin C supplements and the risk of age-related cataract: a population-based prospective cohort study in women,” (18 November 2009) American Journal of Clinical Nutrition.

[16] Susanna C Larsson et al., “Multivitamin use and breast cancer incidence in a prospective cohort of Swedish women,” American Journal of Clinical Nutrition (May 2010).

[17] “Vitamin supplements: Who should take them and who should not,” The Medical Letter 47 (2005): 57-58.

An autism epidemic?

My post on vaccines and autism got over 16,000 hits, which dwarfs anything else I’ve said about anything.

So, in the spirit of “give the people what they want,” I offer another little tidbit that is useful for thinking about these sorts of things.

In my clinical work, people will often ask me “Why is there so much more autism these days?” And, it is this supposed increase that many anti-vaccination efforts are intended to both combat and explain.

We certainly hear more about autism. But, does this mean that there is more of it around?

One difficulty is that diagnostic criteria change—what it takes to label someone as “autistic” has not always been identical, in all places, and in all times. It is, in short, “easier” to be labeled an autistic today than it used to be.

Let’s take a more straightforward example: suppose we define hypertension (high blood pressure) as anyone with a systolic blood pressure > 150. We find a number of people in our town with high blood pressure. But, later we redefine high blood pressure to be>140–perhaps we’ve found that it remains dangerous to have pressures from 140-150 as well as over 150.

With this new definition, we diagnose everyone we caught before, plus a whole bunch of “new” people that have suddenly become sick—but only under the new definition. Nothing has changed, except the way we define the world and how we label things.

I recently read a book that summarizes this sort of thing as it relates to autism specifically:

…several recent studies suggest that the autism epidemic may be an illusion. In one investigation, researchers tracked the prevalence of autism diagnoses between 1992 and 1998 in an area of England using the same diagnostic criteria at both time points (Chakrabarti & Fombonne, 2005). Contrary to what we’d expect if there were an autism epidemic, the authors found no increase whatsoever in the prevalence of autism over time. Another study found evidence for a phenomenon termed “diagnostic substitution”: As rates of the autism diagnosis soared in the United States between 1994 and 2003, diagnoses of mental retardation and learning disabilities combined decreased at about an equal rate. This finding suggests that diagnoses of autism may be “swapping places” with other, less fashionable, diagnoses. The same trend may be unfolding in the case of diagnoses of language disorders, which have become less frequent as autism diagnoses have become more popular (Bishop, Whitehouse, Watt, & Line, 2008). All of these studies offer no support for an autism epidemic: They suggest that diagnoses of autism are skyrocketing in the absence of any genuine increase in autism’s prevalence. As a consequence, efforts to account for this epidemic by vaccines may be pointless.[1]

Both clinicians and parents may get better at choosing diagnoses, and may be influenced by other factors too. After all, it is more hopeful to label a child with “autism” (which can often be helped considerably with early and aggressive intervention) than with “mental retardation” (which may be much less amenable to improvement, depending upon the cause).

Government and schools also have an influence, since they may create certain programs or funding helps for families with autism—this gives them a real incentive to be formally diagnosed and recorded and tracked, which means they will be there when researchers go looking to determine the prevalence of autism. I certainly provide far more paperwork for people with autism now than I did ten years ago.

There’s an old medical aphorism that says, “You can’t diagnose what you don’t think of.” It’s true. And, you will also tend to diagnose more of what you think of more often.

And, we tend to think of things, or even bother looking for them, when there’s some good reason to do so.

After all, there are a couple of hundred different viruses that cause the common cold. But, I don’t have clinical tools to easily distinguish them, since I can’t do a single thing about any of them that makes a difference.

But, if there was a drug that could cure types #1-50, while doing nothing for #51-200, I’d probably look a lot harder for types#1-50. And, as a result, diagnoses would increase substantially, even though the actual prevalence and incidence of the disease doesn’t change at all.

Some of the increase in diagnosis of major depression is probably due to this sort of phenomenon: as medications that are better tolerated were developed, both doctors and patients had a reason to pay attention and to make formal diagnoses: because there was the potential of doing something.

So, we might look at the “increase” in autism diagnosis as a good thing. It could be that we’re finally recognizing a needy group that has been there all along, and we are doing so partly because we can help them. And, that recognition will lead to us being able to do even more.

And, that’s not something to panic about or try to “fix” at all. Least of all by forgoing vaccines.


[1] Scott O. Lilienfeld, Steven Jay Lynn, John Ruscio, Barry L. Beyerstein, 50 Great Myths of Popular Psychology: Shattering Widespread Misconceptions about Human Behavior (Wiley-Blackwell, 2009), 175. ISBN 9781405131124