Monday, April 30, 2012

Zip Code as Important as Genetic Code in Childhood Obesity

The original heading on this article -- reproduced above -- is a vast exaggeration.  What was actually found was an assembly of mostly non-significant (>.05) relationships.  And it was actually found that the environment around you had NO EFFECT on adults.  It was only among children that some connection was observed.

Comparing Seattle and San Diego strikes me as a bit bizarre and creating large difficulties for control. I haven't bothered to look it up but as far as I am aware,  San Diego has a much higher proportion of blacks and Hispanics than Seattle does.  So how do you control for ethnicity?  You could say, "We will look at whites only" but the whites in the two places might not be comparable.  Due to the well known "white flight" phenomenon, many of the whites in San Diego might be "left behind" people in various ways.

I also believe that San Diego has America's largest population of retired admirals but although that is unlikely to have affected the results below, it is another warning that the populations of the two cities might be non comparable in a number of ways.

And even if we accept that the controls were adequate what do the results mean?  How does "neighborhood" exert its effect?  I doubt that the neighborhood itself does anything.  But maybe people who live in nicer areas send their kids out to exercise of various sorts more.  It may be an exercise effect rather than a neighborhood effect that we are looking at.  That it is something like that is suggested by the fact that the environment had no effect on adult obesity

Nearly 18 percent of U.S. school-aged children and adolescents are obese, as the rate of childhood obesity has more than tripled in the past 30 years. The prevalence of obesity puts children at greater risk of developing heart disease, type 2 diabetes, stroke and other illnesses, and of suffering severe obesity as adults. New study results indicate that where a child lives, including factors such as the neighborhood's walkability, proximity to higher quality parks, and access to healthy food, has an important effect on obesity rates. Researchers found that children living in neighborhoods with favorable neighborhood environment attributes had 59 percent lower odds of being obese.

"Obesogenic Neighborhood Environments, Child and Parent Obesity: The Neighborhood Impact on Kids Study" was published in a special theme issue of the American Journal of Preventive Medicine. Led by Brian Saelens, PhD, of Seattle Children's Research Institute, this is among the first neighborhood environment studies to look at a combination of nutrition and physical activity environments and to assess children and their parents. It is also among the largest studies of its kind to use objective geographic information system (GIS) data to examine the physical activity and healthy food option attributes of a neighborhood related to obesity.

Researchers used GIS to assess Seattle and San Diego area neighborhoods' nutrition and physical activity environments. Nutrition environments were defined based on supermarket availability and concentration of fast food restaurants. Physical activity environments were defined based on environmental factors related to neighborhood walkability and at least one park with more or better amenities for children. Kids that lived in neighborhoods that were poorer in physical activity and nutrition environment had the highest rates of obesity -- almost 16 percent -- in the study. This figure is similar to the national average. On the flip side, only eight percent of children were obese in neighborhoods where physical activity and nutrition environments were positive.

"People think of childhood obesity and immediately think about an individual's physical activity and nutrition behaviors, but they do not necessarily equate obesity with where people live," said Dr. Saelens, who is also a professor of pediatrics at the University of Washington. "Everyone from parents to policymakers should pay more attention to zip codes because they could have a big impact on weight."

Fast food may not be as easy to come by in the Seattle area, based on the study. There were 3,474 fast food locations in San Diego County, as compared to 1,660 in King County, Wash. On a county-level block group average basis, San Diego had 2.0 fast food locations per block group, and King County had 1.1.

Numerous national health organizations have identified neighborhood environment and built environment, including healthy food and physical activity opportunities, as important factors in childhood obesity, including the Institute of Medicine and the Centers for Disease Control and Prevention. "Our data support recommendations from these groups that we need to change our environments to make them more supportive of physical activity and nutrition," said Saelens.


Salad growers find that salad is good for you

With such a tiny sample (10) this is PR, not science.  It is amazing what academic journals will print these days.  As long as it serves the antioxidant religion, I guess ....

Researchers have found that antioxidant-rich watercress can alleviate the natural stress put on our body by a workout. And they found that participants with no watercress in their system who ate the leafy vegetable just two hours before high level exercise still experienced the same level of protection.

Though regular moderate exercise is known to be good for us, the increased demand on our bodies can cause damage to our DNA.

According to a new study from scientists at Edinburgh Napier University and the University of Ulster, eating watercress can prevent some of the damage caused by high intensity exercise and help maximise the benefits of a tough workout.  The study findings have now been published in the British Journal of Nutrition.

Study leader Dr Mark Fogarty, from Edinburgh Napier's School of Life, Sport and Social Sciences, said: "Although we are all aware of how good exercise can be for our bodies, pounding the treadmill, lifting weights, or doing high-levels of training can take its toll. The increased demand on the body for energy can create a build-up of free radicals which can damage our DNA.

"What we've found is that consuming a relatively small amount of watercress each day can help raise the levels of important antioxidant vitamins which may help protect our bodies, and allow us to enjoy the rewards of keeping fit. It's an interesting step forward in sports nutrition development and research."

Ten healthy men, aged on average of 23 years, participated in the study. For eight weeks they were given 85 grams of watercress -- a small bag -- and asked to participate in high-level exercise on the treadmill. An eight week study with no watercress consumption was carried out to act as a control.

The scientists also tested whether the protection properties of watercress were affected by the regularity of consumption.

Dr Fogarty said: "We put participants through short bursts of intense exercise and found that those who had not eaten watercress were found to have more DNA damage than those that did not. What was also fascinating is that the effect of eating watercress was not reliant on an accumulative build-up in our bodies. Those that ate the vegetable just two hours before exercise experienced the same benefits as those who had consumed the vegetable for eight weeks."

The study was sponsored by Vitacress Salads, one of Europe's growers of watercress.


No comments: