Yes, autism is on the rise. Read this before blaming vaccines.

Waiting for the rain, © EEG

Because I work on HIV vaccine design, lately I've often been involved in debates concerning the safety of vaccines. I have the greatest respect for parents who struggle with disabilities of any kind, especially in children. I'm a parent too and can't even imagine what life is like when your child has a permanent disability. But I'm also a scientist, and I believe in the good cause of my work. My boss has been working day and night for thirty years on a vaccine against HIV because her best friend died of AIDS. We have pictures of AIDS orphans on our desks. We are not monsters, we are not part of a conspiracy, we are not paid by companies to fool people.

In fact, because we do basic research, our salary will be paid whether or not we do succeed in finding a vaccine. It's just our job, and we have no financial gain in this. If you want to point fingers, do it at companies who do make a profit out of health care, or out of selling plastic (and hence bypassing necessary health testing), or out of selling food. As a parent, I am the first to be concerned about the health of our children. I don't accept anything blindly without doing research, be it a vaccine or a drug or a type of food.

I've discussed aluminum in vaccines and why it's a good idea to spread out the shots during the first year of life; I've also discussed why I decided to wait before letting my daughter have the HPV shot. At the same time, parents concerned about autism are right to be alarmed: if you look at the latest numbers published by the CDC, the prevalence of autism in children has doubled. However, this trend has supposedly started in the last two decades whereas vaccines have been around much longer than that [1]. It's true that the US have an aggressive vaccine schedule for infants and I suspect it's tailored to reduce the number of office visits as copays are expensive and insurance companies need to make their profits. So yes, just like other parents, I am bitter at the system. I am bitter at companies profiting out of the health of my own children, not at researchers working hard at finding a cure for deadly diseases. My plea today is to separate the two: the cure, which, just like any other cure, should be used wisely and with good measure and balance, and the people making profits out of the cure.    

For example, nobody argues that antibiotics save lives. Unfortunately, today you find antibacterial stuff in soaps, detergent, even toothpaste. Doctors overprescribe antibiotics all the time. And then of course, poultry, beef and pork come loaded with antibiotics. This has led to extremely aggressive, antibiotic resistant superbugs like CRE. Yet nobody dreams of refusing antibiotics when they are really needed. That's because we all know that if you don't take them you might in fact lose your life.

What our society needs is stop pointing fingers, quit all the conspiracy crap, and instead sit at the table and discuss better health practices that don't put profits first but health and good care instead.

How should we address the rise in autism cases? I don't have an answer to this, but I did find a bunch of papers that got me thinking. I list them below.

DISCLAIMER: I'm not discussing these papers to point at a cause of autism. In fact, I believe that we will never find a cause, just like we will never find a cause of cancer. Like I stated in my post last week, we need to think of our lives as a complex orchestra where DNA, RNA, proteins and the environment all play together to create the beautiful symphony of our life. There never is one such thing as a direct cause. Often it's just genetics. Even more often is a genetic predisposition combined with multiple sets of environmental exposures, lifestyle, and diet. If your child has autism, please focus your energy in taking care of that child rather than trying to find a cause.

1) This study [1] looked into the raising numbers of autism cases:

"Diagnosed autism prevalence has risen dramatically in the U.S over the last several decades and continued to trend upward as of birth year 2005. The increase is mainly real and has occurred mostly since the late 1980s. In contrast, children's exposure to most of the top ten toxic compounds has remained flat or decreased over this same time frame. Environmental factors with increasing temporal trends can help suggest hypotheses for drivers of autism that merit further investigation [1]." 

So the threat is real. Yet vaccines have been around much longer than the 1980s.

2) Studies have found a higher incidence of autism in California, in higher educated families. This may be biased by the fact that people with a higher education will be more inclined to have their children tested for autism. But one study in particular [2] found another possible association:

"Our study adds to previous work in California showing a relation between traffic-related air pollution and autism, and adds similar findings in an eastern US state, with results consistent with increased susceptibility in the third-trimester [2]." 

The researchers monitored the air particulate at the birth address of the child starting from preconception through the child's first birthday.

 3) Breast feeding may play a protective role against autism spectrum disorders [3].

4) Inflammation may play a role. Le Belle et al. [4] used a mouse model to test the following hypothesis:

"A period of mild brain overgrowth with an unknown etiology has been identified as one of the most common phenotypes in autism. Here, we test the hypothesis that maternal inflammation during critical periods of embryonic development can cause brain overgrowth and autism-associated behaviors as a result of altered neural stem cell function [4]."

What they found supports the idea that, paired with genetic susceptibility, an infection in the pregnant mother could indeed higher the risk of developing autism in the child.

5) But one of the most fascinating associations I found is between gut microbiome and autism. Newborns are born without any bacteria in their guts and colonization begins right after birth. Vaginal birth vs. cesarean, breast fed vs. formula seem to be factors associated to the gut microbiota found in infants.

"Over the first years of life the gut microbiome is changing and remodeling, ultimately resembling an adult gut microbiome by year 3. This suggests there is a “core microbiome” that is the hallmark of a healthy individual [5]." 

This is particularly important because the microbiota community carries millions of genes whose expression affects our own physiology. The type and number of bacteria in our guts can influence the health and good functioning of our immune system.

Now, here's the worrisome bit:

"Broad-spectrum antibiotics are often prescribed to infants in the Western world in an attempt to protect the developing child from disease. In addition to conferring antibiotic resistance in infancy, antibiotic over usage can significantly disrupt the overall ecology of the gut microbiota, alter the abundances of resident gut bacteria, and potentially bias the child toward certain diseases [6]."

I'm not making a case that antibiotics are bad, just like I will never say that vaccines are bad. I'm just raising a flag that, like in all things, a good measure should be practiced. Antibiotics are a great means to fight infections. But is it safe to use them routinely to prevent infection?

The following study [7] is from 2000, so maybe a bit outdated, and the sample number is awfully low. Still, this is what it had to say:

"In most cases symptoms of autism begin in early infancy. However, a subset of children appears to develop normally until a clear deterioration is observed. Many parents of children with "regressive"-onset autism have noted antecedent antibiotic exposure followed by chronic diarrhea. We speculated that, in a subgroup of children, disruption of indigenous gut flora might promote colonization by one or more neurotoxin-producing bacteria, contributing, at least in part, to their autistic symptomatology [7]."

The study has a huge limit: they tested their hypothesis on 11 children that matched the above criteria (the onset of autism symptoms were observed after administration of antibiotics and subsequent diarrhea), which is an extremely small number. The children were given oral antibiotics and a slight improvement in behavior was noted, not the effects had completely waned by follow-up. Nothing conclusive, but definitely this study makes a case for further investigation.

In a more recent review, Critchfield et al. suggest that:

"Autism spectrum disorders are a diverse group of disorders caused by a complex interplay between genetic and environmental components. There is a range of indications that alterations in the intestinal microbiota in the gut might contribute to the disorder in a substantial number of individuals. Probiotics can be useful to restore the microbial balance in the intestine, to relieve gastrointestinal problems and to attenuate immunological abnormalities. Whether the use of probiotics by children with autism can lead to improvements in behaviors needs to be established in well-controlled trials with sufficient group sizes [8]." 

Please don't take any of this as prescriptions or recommendations. I am NOT a medical doctor. I'm a scientist and I like to pose questions and investigate possible answers. If you have particular concerns about your children, talk to your doctor. The references mentioned above are meant as guidelines. Print them out, read them carefully, and then discuss them with your physician.

[1] Nevison CD (2014). A comparison of temporal trends in United States autism prevalence to trends in suspected environmental factors. Environmental health : a global access science source, 13 PMID: 25189402

[2] Kalkbrenner AE, Windham GC, Serre ML, Akita Y, Wang X, Hoffman K, Thayer BP, & Daniels JL (2015). Particulate matter exposure, prenatal and postnatal windows of susceptibility, and autism spectrum disorders. Epidemiology (Cambridge, Mass.), 26 (1), 30-42 PMID: 25286049

[3] Al-Farsi YM, Al-Sharbati MM, Waly MI, Al-Farsi OA, Al-Shafaee MA, Al-Khaduri MM, Trivedi MS, & Deth RC (2012). Effect of suboptimal breast-feeding on occurrence of autism: a case-control study. Nutrition (Burbank, Los Angeles County, Calif.), 28 (7-8) PMID: 22541054

[4] Le Belle JE, Sperry J, Ngo A, Ghochani Y, Laks DR, López-Aranda M, Silva AJ, & Kornblum HI (2014). Maternal inflammation contributes to brain overgrowth and autism-associated behaviors through altered redox signaling in stem and progenitor cells. Stem cell reports, 3 (5), 725-34 PMID: 25418720

[5] Mulle, J., Sharp, W., & Cubells, J. (2013). The Gut Microbiome: A New Frontier in Autism Research Current Psychiatry Reports, 15 (2) DOI: 10.1007/s11920-012-0337-0

[6] Arrieta, M., Stiemsma, L., Amenyogbe, N., Brown, E., & Finlay, B. (2014). The Intestinal Microbiome in Early Life: Health and Disease Frontiers in Immunology, 5 DOI: 10.3389/fimmu.2014.00427

[7] Sandler RH, Finegold SM, Bolte ER, Buchanan CP, Maxwell AP, Väisänen ML, Nelson MN, & Wexler HM (2000). Short-term benefit from oral vancomycin treatment of regressive-onset autism. Journal of child neurology, 15 (7), 429-35 PMID: 10921511

[8] Critchfield, J., van Hemert, S., Ash, M., Mulder, L., & Ashwood, P. (2011). The Potential Role of Probiotics in the Management of Childhood Autism Spectrum Disorders Gastroenterology Research and Practice, 2011, 1-8 DOI: 10.1155/2011/161358