Tuesday, May 31, 2011

Google Continues to Use its Power for Public Health Good


Yesterday, Google announced its new surveillance system for Dengue Fever. Dengue Fever is a disease caused by four related viruses spread by a particular species of mosquito. It can cause high fever, rash, muscle and joint pain, and in severe cases- bleeding, a sudden drop in blood pressure (shock) and death. Millions of cases of Dengue infection occur worldwide each year. Most often, dengue fever occurs in urban areas of tropical and subtropical regions.

The system is similar to that which was previously released as their Google Flu Trends program. These systems use search queries within Google (for example those that enter the disease's name and/or symptoms) to identify trends. The Dengue system also takes advantage of a new feature called Google Correlate, which shows previously unknown correlations between search terms. These correlations allow researchers to model real world behaviors by examining internet search trends. For those who may be skeptical of this model, you should check out a publication (co-authored by Google and the Centers for Disease Control and Prevention-CDC) in the 2009 Nature Journal . The article reports that "because relative frequencies of certain queries were highly correlated with the percentage of physician visits in which a patient presents with influenza-like symptoms, we can accurately estimate the current level of weekly influenza activity in each region of the United States, with a reporting lag of about one day."

This is a pretty exciting addition to public health surveillance (where the goal is systematic, ongoing, data collection that is used to monitor trends, identify priorities, direct resources, identify emerging hazards, and evaluate interventions).

This is not the first time that Google has jumped into the public health field with an impressive contribution. In 2010, Google searches related to suicide started appearing with a message guiding users to the toll-free number for the National Suicide Prevention Lifeline. The number is 1-800-273-8255. Triggered by searches such as "I want to die" or "ways to commit suicide," the number is listed next to an icon of a red telephone, at the top of the search results.

The addition of the Lifeline number came shortly after (at the suggestion of a Google user), the company started displaying the hotline for the American Association of Poison Control Centers after searches for "poison emergency."

These cases of Google's work in public health are great examples of effective health communication and public health principles:
  • Identifying the primary channels through which your audience searches for health information (more and more are utilizing the internet) and delivering accurate and effective information and/or interventions via those channels.
  • Maximizing data driven surveillance systems- using existing data (e.g., internet searches) to identify public health trends.
  • Building strong partnerships (as evidenced by the publication by Google and CDC) CDC has partnered with a company with specific expertise and resources in an area that can be invaluable to their work.

Monday, May 23, 2011

The China Study II: Wheat may not be so bad if you eat 221 g or more of animal food daily

In previous posts on this blog covering the China Study II data we’ve looked at the competing effects of various foods, including wheat and animal foods. Unfortunately we have had to stick to the broad group categories available from the specific data subset used; e.g., animal foods, instead of categories of animal foods such as dairy, seafood, and beef. This is still a problem, until I can find the time to get more of the China Study II data in a format that can be reliably used for multivariate analyses.

What we haven’t done yet, however, is to look at moderating effects. And that is something we can do now.  A moderating effect is the effect of a variable on the effect of another variable on a third. Sounds complicated, but WarpPLS makes it very easy to test moderating effects. All you have to do is to make a variable (e.g., animal food intake) point at a direct link (e.g., between wheat flour intake and mortality). The moderating effect is shown on the graph as a dashed arrow going from a variable to a link between two variables.

The graph below shows the results of an analysis where animal food intake (Afoods) is hypothesized to moderate the effects of wheat flour intake (Wheat) on mortality in the 35 to 69 age range (Mor35_69) and mortality in the 70 to 79 age range (Mor70_79). A basic linear algorithm was used, whereby standardized partial regression coefficients, both moderating and direct, are calculated based on the equations of best-fitting lines.


From the graph above we can tell that wheat flour intake increases mortality significantly in both age ranges; in the 35 to 69 age range (beta=0.17, P=0.05), and in the 70 to 79 age range (beta=0.24, P=0.01). This is a finding that we have seen before on previous posts, and that has been one of the main findings of Denise Minger’s analysis of the China Study data. Denise and I used different data subsets and analysis methods, and reached essentially the same results.

But here is what is interesting about the moderating effects analysis results summarized on the graph above. They suggest that animal food intake significantly reduces the negative effect of wheat flour consumption on mortality in the 70 to 79 age range (beta=-0.22, P<0.01). This is a relatively strong moderating effect. The moderating effect of animal food intake is not significant for the 35 to 69 age range (beta=-0.00, P=0.50); the beta here is negative but very low, suggesting a very weak protective effect.

Below are two standardized plots showing the relationships between wheat flour intake and mortality in the 70 to 79 age range when animal food intake is low (left plot) and high (right plot). As you can see, the best-fitting line is flat on the right plot, meaning that wheat flour intake has no effect on mortality in the 70 to 79 age range when animal food intake is high. When animal food intake is low (left plot), the effect of wheat flour intake on mortality in this range is significant; its strength is indicated by the upward slope of the best-fitting line.


What these results seem to be telling us is that wheat flour consumption contributes to early death for several people, perhaps those who are most sensitive or intolerant to wheat. These people are represented in the variable measuring mortality in the 35 to 69 age range, and not in the 70 to 79 age range, since they died before reaching the age of 70.

Those in the 70 to 79 age range may be the least sensitive ones, and for whom animal food intake seems to be protective. But only if animal food intake is above a certain level. This is not a ringing endorsement of wheat, but certainly helps explain wheat consumption in long-living groups around the world, including the French.

How much animal food does it take for the protective effect to be observed? In the China Study II sample, it is about 221 g/day or more. That is approximately the intake level above which the relationship between wheat flour intake and mortality in the 70 to 79 age range becomes statistically indistinguishable from zero. That is a little less than ½ lb, or 7.9 oz, of animal food intake per day.

Monday, May 16, 2011

Book review: Biology for Bodybuilders

The photos below show Doug Miller and his wife, Stephanie Miller. Doug is one of the most successful natural bodybuilders in the U.S.A. today. He is also a manager at an economics consulting firm and an entrepreneur. As if these were not enough, now he can add book author to his list of accomplishments. His book, Biology for Bodybuilders, has just been published.

(Source: www.dougmillerpro.com)

Doug studied biochemistry, molecular biology, and economics at the undergraduate level. His co-authors are Glenn Ellmers and Kevin Fontaine. Glenn is a regular commenter on this blog, a professional writer, and a certified Strength and Conditioning Specialist. Dr. Fontaine is an Associate Professor at the Johns Hopkins University’s School of Medicine and Bloomberg School of Public Health.

Biology for Bodybuilders is written in the first person by Doug, which is one of the appealing aspects of the book. This also allows Doug to say that his co-authors disagree with him sometimes, even as he outlines what works for him. Both Glenn and Kevin are described as following Paleolithic dieting approaches. Doug follows a more old school bodybuilding approach to dieting – e.g., he eats grains, and has multiple balanced meals everyday.

This relaxed approach to team writing neutralizes criticism from those who do not agree with Doug, at least to a certain extent. Maybe it was done on purpose; a smart idea. For example, I do not agree with everything Doug says in the book, but neither do Doug’s co-authors, by his own admission. Still, one thing we all have to agree with – from a competitive sports perspective, no one can question success.

At less than 120 pages, the book is certainly not encyclopedic, but it is quite packed with details about human physiology and metabolism for a book of this size. The scientific details are delivered in a direct and simple manner, through what I would describe as very good writing.

Doug has interesting ideas on how to push his limits as a bodybuilder. For example, he likes to train for muscle hypertrophy at around 20-30 lbs above his contest weight. Also, he likes to exercise at high repetition ranges, which many believe is not optimal for muscle growth. He does that even for mass building exercises, such as the deadlift. In this video he deadlifts 405 lbs for 27 repetitions.

Here it is important to point out that whether one is working out in the anaerobic range, which is where muscle hypertrophy tends to be maximized, is defined not by the number of repetitions but by the number of seconds a muscle group is placed under stress. The anaerobic range goes from around 20 to 120 seconds. If one does many repetitions, but does them fast, he or she will be in the anaerobic range. Incidentally, this is the range of strength training at which glycogen depletion is maximized.

I am not a bodybuilder, nor do I plan on becoming one, but I do admire athletes that excel in narrow sports. Also, I strongly believe in the health-promoting effects of moderate glycogen-depleting exercise, which includes strength training and sprints. Perhaps what top athletes like Doug do is not exactly optimal for long-term health, but it certainly beats sedentary behavior hands down. Or maybe top athletes will live long and healthy lives because the genetic makeup that allows them to be successful athletes is also conducive to great health.

In this respect, however, Doug is one of the people who have gotten the closest to convincing me that genes do not influence so much what one can achieve as a bodybuilder. In the book he shows a photo of himself at age 18, when he apparently weighed not much more than 135 lbs. Now, in his early 30s, he weighs 210-225 lbs during the offseason, at a height of 5'9". He has achieved this without taking steroids. Maybe he is a good example of compensatory adaptation, where obstacles lead to success.

If you are interested in natural bodybuilding, and/or the biology behind it, this book is highly recommended!

Monday, May 9, 2011

Looking for a good orthodontist? My recommendation is Dr. Meat

The figure below is one of many in Weston Price’s outstanding book Nutrition and Physical Degeneration showing evidence of teeth crowding among children whose parents moved from a traditional diet of minimally processed foods to a Westernized diet.


Tooth crowding and other forms of malocclusion are widespread and on the rise in populations that have adopted Westernized diets (most of us). Some blame it on dental caries, particularly in early childhood; dental caries are also a hallmark of Westernized diets. Varrela (2007), however, in a study of Finnish skulls from the 15th and 16th centuries found evidence of dental caries, but not of malocclusion, which Varrela reported as fairly high in modern Finns.

Why does malocclusion occur at all in the context of Westernized diets? Lombardi (1982) put forth an evolutionary hypothesis:

“In modern man there is little attrition of the teeth because of a soft, processed diet; this can result in dental crowding and impaction of the third molars. It is postulated that the tooth-jaw size discrepancy apparent in modern man as dental crowding is, in primitive man, a crucial biologic adaptation imposed by the selection pressures of a demanding diet that maintains sufficient chewing surface area for long-term survival. Selection pressures for teeth large enough to withstand a rigorous diet have been relaxed only recently in advanced populations, and the slow pace of evolutionary change has not yet brought the teeth and jaws into harmonious relationship.”

So what is one to do? Apparently getting babies to eat meat is not a bad idea. They may well just chew on it for a while and spit it out. The likelihood of meat inducing dental caries is very low, as most low carbers can attest. (In fact, low carbers who eat mostly meat often see dental caries heal.)

Concerned about the baby choking on meat? At the time of this writing a Google search yielded this: No results found for “baby choked on meat”. Conversely, Google returned 219 hits for “baby choked on milk”.

What if you have a child with crowded teeth as a preteen or teen? Too late? Should you get him or her to use “cute” braces? Our daughter had crowded teeth a few years ago, as a preteen. It overlapped with the period of my transformation, which meant that she started having a lot more natural foods to eat. There were more of those around, some of which require serious chewing, and less industrialized soft foods. Those natural foods included hard-to-chew beef cuts, served multiple times a week.

We noticed improvement right away, and in a few years the crowding disappeared. Now she has the kind of smile that could land her a job as a toothpaste model:


The key seems to be to start early, in developmental years. If you are an adult with crowded teeth, malocclusion may not be solved by either tough foods or braces. With braces, you may even end up with other problems (see this).

Sunday, May 8, 2011

Will New Ads in Georgia "Stop Childhood Obesity" or Increase Stigma and Bullying?

On Friday's Today show, there was an interesting analysis of a new campaign from the Georgia Child Health Alliance (GCHA) aimed at reducing childhood obesity. According to the GCHA website, the Warning: Stop Childhood Obesity media campaign "is part of a large-scale public awareness campaign designed to educate Georgians on the childhood obesity epidemic facing our state. Backed by market research, the campaign’s warning messages about obesity are developed to reach parents and children using communication vehicles such as billboards, television, radio and more".

From the Today show segment (which featured the campaign's Director, a child actor featured in the ads, and a child psychologist) we learned that this media campaign is part one of a three part campaign. The three parts were briefly outlined:

1- Raise awareness about childhood obesity; letting kids voice their struggle in their own words.
2- "Activate"- focus on healthy eating and activity
3- Focus on real solutions

While the GCHA outlines their strategic mission for this campaign, they are hearing some major objections to their approach and it continues to grab national headlines. The major concerns voiced by objectors such as Rebecca Puhl (a weight discrimination expert from Yale University), are that the ads will increase stigma for overweight kids (which could increase their experience of bullying) and that the ads will be ineffective due to their fear-based approach. In my review of the ads, I have mixed (mostly negative) feelings about their development and implementation:
  • Strike One: The goal of this campaign is listed as "raising awareness". These may be my two least favorite terms in all of public health. "Raising awareness" is too vague and does not lend itself to being evaluated. In actuality, campaign developers usually want to "increase knowledge" or "change perceptions" or "change behavior" (e.g., calling the 800 number on the screen). These are all things which can actually be measured and should be stated more clearly.
  • Strike Two: When the Today show asked the Campaign director about the audience for these ads, he replied "parents, kids, and educators". Again, this is way too vague. Your message and call to action (i.e., what you want the viewer to do after watching the ad) would be completely different for each of those audiences. For example, you may want educators to reach out to the parents of overweight kids in their classes or you may want kids to tell an adult if they are being bullied about their weight. These messages need to be tailored to each audience.
  • Strike Three: These ads definitely fall into the "fear-based" category. As you watch them, the ads read "WARNING" in bold red letters and you hear a "boom" (kinda like on "Law & Order) as the statistics run across the screen. As I have mentioned in previous blog posts, fear-based approaches have been found to be ineffective in other areas of prevention (e.g., alcohol and other drugs).
  • In terms of redeeming factors, it does seem that the campaign was developed using formative research which included focus groups with overweight kids. The results of these focus groups were used to develop the dialogue read by child actors in the ads so that it would be "in their words". If kids are the audience for these ads, then the age appropriate priorities and dialogue (with the inclusion of child actors) is positive. From health behavior theory (e.g., Social Learning Theory), we know that kids will respond better if they relate to those in the ads.
Of course, it is unclear if they also focus group tested the ads and billboards after initial development, before they were rolled out. It is also unclear how they are being evaluated and what the ultimate goals are (beyond "increased awareness"). I'll be interested to see parts two and three rolled out and hope to include follow up thoughts here on Pop Health.

Tuesday, May 3, 2011

From The West Wing to the National Health Care Debate

Anyone who knows me well knows that "The American President" is one of my favorite movies. If it is a favorite of yours as well, you may recognize that the actress who plays Press Secretary Robin McCall also plays National Security Advisor Dr. Nancy McNally in "The West Wing". The actress is Anna Deavere Smith.

This week in my "Qualitative Research Methods in Community Health" class, we discussed ethnography. Specifically we discussed Ms. Smith's work as an example of performance ethnography. For over a decade, she has interviewed people across the country and used the "data" to develop a one-woman show. Her newest play is called "Let Me Down Easy" and its goal is to show the human side of the national health care debate. I highly recommend viewing the 10-minute excerpt and interview here.

I'm so sorry that I missed her play when it came to Philadelphia earlier this year because I think it is an amazing example of the richness of data collected using qualitative methods. It is often argued that qualitative methods are too "soft" and limited in view. I've heard them described as "basically just journalism". However, I would argue that qualitative methods are essential to the success of public health.

Instead of surveys and databases, these methods collect data via interview, discussion, and observation. The research is meant to discover the complex relationship between personal and social meaning, individual and cultural practices, and the material environment or context. In contrast to what we have learned since grade school science about the scientific method and generalizability of findings- here the focus is on obtaining a deeper understanding of a population or phenomenon.

Ms. Smith conducted over 300 interviews for "Let Me Down Easy" and ultimately condensed her findings to show the experience of contemporary health care through the eyes of 20 individuals. These kinds of stories are incredibly powerful in public health. They open our eyes to challenges that we never would have found via survey...because we wouldn't have known to ask the right questions. They allow us to share stories with policymakers so they can see the impact of their decisions beyond the sterile statistics often cited. They can allow us to explore experiences or illnesses that occur in too small a population to survey.

Ideally, quantitative and qualitative methods should be used together to create the strongest public health research design possible. It should not be us vs. them...but instead a joint effort. I encourage us all to see the human side of health care reform when Ms. Smith's play airs on PBS "Great Performances" next season.

Monday, May 2, 2011

Strength training plus fasting regularly, and becoming diabetic!? No, it is just compensatory adaptation at work

One common outcome of doing glycogen-depleting exercise (e.g., strength training, sprinting) in combination with intermittent fasting is an increase in growth hormone (GH) levels. See this post for a graph showing the acute effect on GH levels of glycogen-depleting exercise. This effect applies to both men and women, and is generally healthy, leading to improvements in mood and many health markers.

It is a bit like GH therapy, with GH being “administered” to you by your own body. Both glycogen-depleting exercise and intermittent fasting increase GH levels; apparently they have an additive effect when done together.

Still, a complaint that one sees a lot from people who have been doing glycogen-depleting exercise and intermittent fasting for a while is that their fasting blood glucose levels go up. This is particularly true for obese folks (after they lose body fat), as obesity tends to be associated with low GH levels, although it is not restricted to the obese. In fact, many people decide to stop what they were doing because they think that they are becoming insulin resistant and on their way to developing type 2 diabetes. And, surely enough, when they stop, their blood glucose levels go down.

Guess what? If your blood glucose levels are going up quite a bit in response to glycogen-depleting exercise and intermittent fasting, maybe you are one of the lucky folks who are very effective at increasing their GH levels. The blood glucose increase effect is temporary, although it can last months, and is indeed caused by insulin resistance. An HbA1c test should also show an increase in hemoglobin glycation.

Over time, however, you will very likely become more insulin sensitive. What is happening is compensatory adaptation, with different short-term and long-term responses. In the short term, your body is trying to become a more efficient fat-burning machine, and GH is involved in this adaptation. But in the short term, GH leads to insulin resistance, probably via actions on muscle and fat cells. This gradually improves in the long term, possibly through a concomitant increase in liver insulin sensitivity and glycogen storage capacity.

This is somewhat similar to the response to GH therapy.

The figure below is from Johannsson et al. (1997). It shows what happened in terms of glucose metabolism when a group of obese men were administered recombinant GH for 9 months. The participants were aged 48–66, and were given in daily doses the equivalent to what would be needed to bring their GH levels to approximately what they were at age 20. For glucose, 5 mmol is about 90 mg, 5.5 is about 99, and 6 is about 108. GDR is glucose disposal rate; a measure of how quickly glucose is cleared from the blood.


As you can see, insulin sensitivity initially goes down for the GH group, and fasting blood glucose goes up quite a lot. But after 9 months the GH group has better insulin sensitivity. Their GDR is the same as in the placebo group, but with lower circulating insulin. The folks in the GH group also have significantly less body fat, and have better health markers, than those who took the placebo.

There is such a thing as sudden-onset type 2-like diabetes, but it is very rare (see Michael’s blog). Usually type 2 diabetes “telegraphs” its arrival through gradually increasing fasting blood glucose and HbA1c. However, those normally come together with other things, notably a decrease in HDL cholesterol and an increase in fasting triglycerides. Folks who do glycogen-depleting exercise and intermittent fasting tend to see the opposite – an increase in HDL cholesterol and a decrease in triglycerides.

So, if you are doing things that have the potential to increase your GH levels, a standard lipid panel can help you try to figure out whether insulin resistance is benign or not, if it happens.

By the way, GH and cortisol levels are correlated, which is often why some associate responses to glycogen-depleting exercise and intermittent fasting with esoteric nonsense that has no basis in scientific research like “adrenal fatigue”. Cortisol levels are meant to go up and down, but they should not go up and stay up while you are sitting down.

Avoid chronic stress, and keep on doing glycogen-depleting exercise and intermittent fasting; there is overwhelming scientific evidence that these things are good for you.