Posts Tagged ‘ diabetes ’

Is Autism Being Overdiagnosed?

Monday, March 31st, 2014

The latest prevalence estimate of Autism Spectrum Disorder (ASD) – 1 in 68 – reignites conversation that we may be overdiagnosing ASD. In part, to some the estimate just feels too high based on clinical and personal experience. And there is worry that we may be flooding an already overwhelmed evaluation and treatment system.

These concerns echo the debates that surrounded the changes in diagnostic criteria that were introduced in the DSM-5 in May 2013 which, to some, were implemented to protect against overdiagnosis of ASD, as I described last December:

The reformulation of the diagnostic criteria – which led to a discontinuation of the category of Asperger Syndrome in favor of a broad-based category of Autism Spectrum Disorder (ASD) – spurred concerns that many youth would no longer qualify for a diagnosis and hence have their intervention options limited. Others suggested that more precise diagnostic criteria are needed to ensure that ASD does not get overdiagnosed. While we await empirical resolution via publication of well-designed studies, it’s clear that the DSM-5 debate will stand out as an important time in which we wrestled (again) with the best way to be inclusive in diagnosis without expanding diagnostic criteria too broadly.

As a result of the changes in DSM-5, it may be that a few years from now we will see a “recalibration” of the prevalence of ASD. The speculations have been that about 10% of children now diagnosed with ASD will no longer meet criteria.

What do we make of these changing estimates in the prevalence of ASD, which have increased tremendously over the past decade and may, sometime in the near future, begin to decrease? This complex issue does not lend itself to a singular answer.  Considering a number of points may help to provide some perspective on how we discuss this question.

PREVALENCE RATES FOR DISORDERS CAN BE “HIGH”

While, as noted above, clinicians, researchers, and policy makers often attempt to interpret the rate of a disorder as a means of ensuring appropriate diagnostics without overdiagnosing, the fact is that there is no magic number or prevalence rate for a disorder. Consider the following:

  • Epilepsy is estimated to affect somewhere between 4-10 per 1000 people; and nearly 10% of the population will experience a seizure in their lifetime
  • Asthma affects almost 10% of children
  • More than 8% of the population is reported to have diabetes

The point? Disorders which can be validated biologically can affect large numbers of people in the population. This means that they are common disorders – not overdiagnosed conditions. The implication for ASD? Simply put, an estimated prevalence of “1 in 68″, in and of itself, does not necessarily imply overdiagnosis.

RATES CAN CHANGE OVER TIME

Part of the concern with the rate of ASD is that it has changed so much over the past decade. The estimates made by the Centers for Disease Control and Prevention (CDC) have gone from 1 in 150, to 1 in 110, to 1 in 88, and now to 1 in 68.  The rates of asthma have also gone up over the past decade, though not nearly as dramatically as those for ASD. A combination of factors have influenced this increased prevalence of asthma, including better recognition and diagnosis, changes in the definition of the disorder, and possibly increases in pathogens in the environment. The takeaway here is that an increase in prevalence over time is not a sufficient argument for overdiagnosis.

THE KEY CONCERN IS THE ROOT OF THE INCREASE OVER TIME

The crux of the debate about ASD is that we may be artificially increasing the prevalence. To consider this point, we need to focus on two two related factors that are primarily responsible for the dramatic changes in ASD prevalence.

First, there is much better screening, recognition, and evaluation. This is a positive step forward – early evaluation leads to early intervention. But as noted in the most recent CDC report, there are still children (primarily those in specific ethnic groups) who are not diagnosed at the same “high” rate as others. So simply lowering the bar for early evaluation is not necessarily a good step forward, and in fact may be counterproductive for many children in the population.

Second, there has been an increase in diagnosing “higher functioning” ASD, that is, ASD without a compromised cognitive level. This is where the conversation about overdiagnosis starts – and where the DSM-5 may lead to a reduction in prevalence over time. The sticky point is that as ASD, by definition, is recognized to occur along a spectrum of severity, it becomes hard to know where to draw the line. At what point would we be missing cases that could profit from intervention? At what point are we pathologizing normative variation in social functioning? There is where we need more informative data on the impact of interventions for those diagnosed and more pointed discussion.

Let’s look at a very different example – potential changes in how high blood pressure is being diagnosed in those 60 years of age and older. New guidelines have suggested that the target blood pressure for determining treatment is 150/90, as opposed to 140/90. The result would be that millions of adults over 60 would no longer be “required” to take medication for high blood pressure. This is a current controversy in medicine and it is being debated. The point here is that the biomedical and health sciences have to make these kinds of decisions for many disorders, and that controversies continue to arise. In other words, these are not simple issues, and they are not resolved easily. We continue to gather more information and bring more opinions to the table to come up with our best practices – and this same principle applies to the current and future conversations about ASD.

SO IS ASD BEING OVERDIAGNOSED?

Right now, this is an important question to ask, but rather than demand an answer, we need to gather more informative data and have more informed discussions that go beyond the prevalence rate. We have these discussions frequently about attention-deficit hyperactivity disorder (ADHD), and they continue. We worry that too many kids are being arbitrarily diagnosed with ADHD and that we may artificially inflate rates of ADHD by making inappropriate demands of toddlers and young children. The concern with ADHD is that we may be preventing kids from being kids, slapping them with inappropriate labels, and giving them medications that are not needed.

The concern with ASD is somewhat different. We are not over-medicating youngsters who are receiving a diagnosis of ASD, particularly those who are “high functioning.” We are offering behavioral interventions to improve social and cognitive skills. What we need to know is if some kids who would receive these kinds of interventions don’t need them or don’t profit from them. That’s essentially the tipping point in the argument described above about how to define high blood pressure. We should move beyond the prevalence rate and begin to look more closely at the efficacy of interventions and if there are better ways to define which kids can be best served by a diagnosis.

But what we don’t want to do is arbitrarily decide that the prevalence rate is “too high” and that we need to lower the bar for screening and evaluation. That would be a big mistake and undermine all the progress made to date in early surveillance and early intervention. Whatever the “true” prevalence rate is (and it will be a moving target), what we do know is that many young children can profit from early intervention and that we need to keep momentum going on understanding more about the causes of ASD, how to best diagnosis it, and how to develop even more powerful interventions.

Autism via Shutterstock.com

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Should Parents Get Their Kids Genome Sequenced?

Wednesday, October 31st, 2012

I just read a terrific series at Time.com about kids and DNA. One of the more intriguing questions posed was: Should you get your child’s genome sequenced? 

The idea might not seem far-fetched. We hear more and more about how genes predict whether or not we will get a disease. So why not have your child’s genome screened for disease genes?

Well, there are a few key considerations to keep in mind (without even thinking about cost or ethics):

Your child’s DNA was probably already screened for major disease genes (really big ones that have severe effects on development) when they were born.

Outside of those genes (there’s probably less than 100 of them), most genetic markers are really not that informative. They give you some sense of increased risk for a disease – but a whole host of environmental factors undoubtedly contribute as well. This is especially true for “common” diseases – like most of the behavioral and emotional disorders of childhood. The fact is for common disorders a fairly high proportion of the population carries some risk genes. So without the ability to offer more specific prediction (as is the case with some of the more rare genes that convey risk for breast cancer, the gene responsible for Huntington’s Disease, etc), it’s not really clear that DNA – right now – holds that much information on your child’s future in terms of common diseases that are influenced by both genes and environment.

Of course, the most important piece of information you would hope to get is not just if your child carries a gene, but what you could do to prevent disease onset. Outside of trying to reduce obvious risk factors that you would want to reduce anyway (e.g., if your child is at risk for diabetes, you would want to monitor their diet very carefully – but you want to do that anyway), there’s not much “genome-tailored” intervention out there.

The fact is that the more we learn about DNA, the more we realize that the landscape is even more complicated than we thought. Unless you think your child is at genetic risk for a disease, and unless there is a powerful genetic screen that carries real information that can inform and direct future behavior, there’s not much practical utility right now to sequencing your child’s genome.

DNA Fingerprinting via Shutterstock.com

 

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Is Maternal Obesity Linked With Autism? Let’s Take A Closer Look At the Study

Monday, April 9th, 2012

You may have seen or heard this morning about a new study that found links between maternal obesity and risk for autism. Here’s a breakdown on the study, the findings, and the take-home message.

What Did This Study Do? The research – published in Pediatrics – explored links between maternal metabolic conditions – specifically diabetes, hypertension, and obesity – and neurodevelopmental disorders in early childhood – particularly autism spectrum disorders (ASD) and developmental delays (DD). The sample was informative – it is a population-based sample in California that is participating in a very large investigation. That said, it’s important to keep in mind that maternal history of diabetes and hypertension during pregnancy, and obesity prior to pregnancy, were gathered retrospectively via a phone interview with the mother when kids were between 24 and 60 months of age, and also from medical records when available (which they were for over half the sample). I highlight this to emphasize that this is far from a definitive study  - not that it’s a bad study, just that it is more like the first word, rather than the last word, on this topic. Do note that the available data suggested that moms could reliably report retrospectively (when they compared their responses to available medical records) – but still, this is not as informative as a prospective study. Moms were selected based on the profiles of 3 types of youth – those with ASD, those with DD, and a general population (GP) control group with neither condition. The researchers then set out to examine if there were links between the maternal metabolic conditions and these three groups of kids. So keep in mind here that this is a statistical test of association, not a more controlled experimental test that can, if you will, “prove” the associations. These kinds of studies are critical first steps to determine if future research is warranted – and not the last steps that convince the scientific community that there is a causative process at play.

What Did They Find? Keeping all of the above in mind (you have to in order to make sense of the results), the study did find a statistical link between a mother’s report of having any of the metabolic conditions and the odds of having a child diagnosed with ASD and DD. It was a moderate statistical finding (meaning statistically significant but clearly not the only factor that contributes risk for ASD and DD). To give you a sense of the data, here are the percentages of mothers with a metabolic condition, broken down by youth diagnosis:

ASD: 28.6% of the mothers

DD: 34.9% of the mothers

GP: 19.4% of the mothers

So you can see how this is a moderate statistical link – for example: 1) the majority of moms of kids with ASD did not have any metabolic conditions, 2) almost 20% of the moms of kids from the general population control group did have a metabolic condition; and 3) the finding comes from the somewhat elevated rates in the ASD and DD groups compared to the GP group. More fine-grained analyses showed that obesity in particular was associated with ASD (after controlling for other factors) – but that diabetes had an effect on a number of cognitive and social outcomes.

What’s The Take-Home Message? There are two messages from my point of view. First, from the perspective of science, the study authors devote most of their attention in their discussion of the results on the biological mechanisms by which maternal diabetes – not maternal obesity – may impact brain development in babies. This is an important avenue for future research and a key contribution from the study. Second, from the perspective of being a prospective parent, the real take-home is that management of maternal metabolic conditions is not only critically important for a number of health outcomes, but also for promoting brain development in the early years of life. Rather than focusing on metabolic conditions as “causes” of disorders, it’s probably better advised to consider them as modifiable influences on development. Maternal obesity is important in this sense because it is one of many factors associated with diabetes – though keep in mind that gestational diabetes can of course occur without obesity. Diabetes – whether in place prior to pregnancy or occurring during pregnancy – is important because it might have biological influences on brain development. So this study just reinforces the bigger message that I hope everyone is aware of – that pregnant women should get vigilant care for potential or existing metabolic conditions during pregnancy, especially diabetes. It’s critical for the well-being of both mom and baby.

Image of word “diabetes” via Shutterstock.com

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Sleep Challenges, Part Two: Childhood And Middle Childhood

Saturday, December 31st, 2011

There are lots of transitions in kids sleep patterns and habits, including big ones that happen during the toddler years. That said, there are also critical changes that occur during childhood and middle childhood (I’m focusing here on 5 – 11 years of age). Most importantly, this is a developmental period where the consequences of sleep deprivation can be especially harmful. So the 2nd installment of my three-part series on sleep challenges focuses on childhood and middle childhood. 

What are the expectations? The biggest issue is that kids are in school for a good part of the year and as such are expected to have consistent sleep schedules that provide sufficient sleep to handle their cognitive, social, and emotional load. Kids between 5 and 11 years old should be getting between 10 and 11 hours of solid sleep every night, with consistent bedtimes and wake-up times. They also should not be tired during the day.

What are the challenges? Let’s start with the biggest challenge – understanding how much sleep your child actually needs and the negative consequences of not getting it. It’s troubling that study after study reports most kids get less sleep than they need – typically 1 hour less per night than is suggested. Add to this the observation from new studies that many kids get inconsistent sleep that can vary greatly from night to night. Such irregular sleep patterns have been shown to lead to substantial metabolic changes that promote risk for obesity and diabetes. And recent scientific reports – such as one that I flagged as one of the most influential studies of 2011 – have shown that sleep deprivation can have accumulating negative effects on cognitive development in childhood during key ages for learning (e.g., from 2nd grade through 4th grade). The culprits that undermine sleep can be many, including a lack of careful supervision of kids’ sleep habits, TV and electronics being available at bedtime (especially in the bedroom), increasing activities outside of school, and increasing time demands after school (such as homework).

How should you handle these challenges? We don’t typically think that sleep needs to be monitored in bigger kids like it does when we are dealing with babies or toddlers. But this isn’t true – in fact kids’ increasing independence screams out for parental monitoring given the sleep epidemic these days and the very real and serious consequences of sleep deprivation. A good start is to become familiar with the signs of sleep deprivation in children, which include the following

  • being very hard to wake-up on a consistent basis
  • sometimes falling asleep much earlier than usual
  • falling asleep frequently in the car
  • hearing from observers (such as teachers) that they seem tired, are yawning a lot, etc

If your child is showing some of these behaviors, it may be time to monitor their sleep habits more closely. Work backwards from when they need to get up and the amount of sleep they require to set a firm bedtime. Limit use of electronics before bedtime (maybe follow at a minimum a 30-minute rule – all technology gets shut down 30 minutes before bedtime). Promote reading as a good form of winding down. And try to be vigilant to make sure your child gets consistent sleep during the week – or put another way, try to avoid irregular sleep habits.

Image of sleeping child via Shutterstock.com

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