Selasa, 31 Mei 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.

Kamis, 26 Mei 2011

Food Reward: a Dominant Factor in Obesity, Part IV

What is Food Reward?

After reading comments on my recent posts, I realized I need to do a better job of defining the term "food reward".  I'm going to take a moment to do that here.  Reward is a psychology term with a specific definition: "a process that reinforces behavior" (1).  Rewarding food is not the same thing as food that tastes good, although they often occur together. 

Read more »

Selasa, 24 Mei 2011

Healthy Skeptic Podcast

Chris Kresser has just posted our recent interview/discussion on his blog The Healthy Skeptic.  You can listen to it on Chris's blog here.  The discussion mostly centered around body fat and food reward.  I also answered a few reader questions.  Here are some highlights:
  • How does the food reward system work? Why did it evolve?
  • Why do certain flavors we don’t initially like become appealing over time?
  • How does industrially processed food affect the food reward system?
  • What’s the most effective diet used to make rats obese in a research setting? What does this tell us about human diet and weight regulation?
  • Do we know why highly rewarding food increases the set point in some people but not in others?
  • How does the food reward theory explain the effectiveness of popular fat loss diets?
  • Does the food reward theory tell us anything about why traditional cultures are generally lean?
  • What does cooking temperature have to do with health?
  • Reader question: How does one lose fat?
  • Reader question: What do I (Stephan) eat?
  • Reader question: Why do many people gain fat with age, especially postmenopausal women?
The podcast is a sneak preview of some of the things I'll be discussing in the near future.  Enjoy!

Minggu, 22 Mei 2011

Fast Food, Weight Gain and Insulin Resistance

CarbSane just posted an interesting new study that fits in nicely with what we're discussing here.  It's part of the US Coronary Artery Risk Development in Young Adults (CARDIA) study, which is a long-term observational study that is publishing many interesting findings.  The new study is titled "Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis" (1).  The results speak for themselves, loud and clear (I've edited some numbers out of the quote for clarity):
Read more »

Rabu, 18 Mei 2011

Food Reward: a Dominant Factor in Obesity, Part III

Low-Fat Diets

In 2000, the International Journal of Obesity published a nice review article of low-fat diet trials.  It included data from 16 controlled trials lasting from 2-12 months and enrolling 1,910 participants (1).  What sets this review apart is it only covered studies that did not include instructions to restrict calorie intake (ad libitum diets).  On average, low-fat dieters reduced their fat intake from 37.7 to 27.5 percent of calories.  Here's what they found:
Read more »

Selasa, 17 Mei 2011

Clarifications About Carbohydrate and Insulin

My statements about carbohydrate and insulin in the previous post seem to have kicked up some dust!  Some people are even suggesting I've gone low-fat!  I'm going to take this opportunity to be more specific about my positions.

I do not think that post-meal insulin spikes contribute to obesity, and they may even oppose it. Elevated fasting insulin is a separate issue-- that's a marker of insulin resistance.  It's important not to confuse the two.  Does insulin resistance contribute to obesity?  I don't know, but it's hypothetically possible since insulin acts like leptin's kid brother in some ways.  As far as I can tell, starch per se and post-meal insulin spikes do not lead to insulin resistance.
Read more »

Jumat, 13 Mei 2011

Healthy Skeptic Podcast and Reader Questions

Chris Kresser, Danny Roddy and I just finished recording the podcast that will be released on May 24th.  It went really well, and we think you'll find it informative and maybe even practical!

Unfortunately, we only got around to answering three of the questions I had selected:
  1. How does one lose fat?
  2. What do I (Stephan) eat?
  3. Why do many people gain fat with age, especially postmenopausal women?
I feel guilty about that, so I'm going to answer three more right now.

Read more »