New mapping data ties where you live to what you weigh

by: MAP COURTESY OF THE COALITION FOR LIVABLE FUTURE - A map tracking residents average Body Mass Index shows that folks in close-in Portland, Lake Oswego, West Linn and areas north of Beaverton tend to have their weight more under control than those in other areas. Residents of unincorporated areas north and west of Beaverton are more likely to have trimmer figures and physiques, while those in much of Beaverton, Aloha and Hillsboro are more likely to sport love handles, beer bellies and other extra pounds.

Those are some of the early findings from health researchers’ effort to track Oregon’s growing obesity problem, by using driver’s license data to compile the Body Mass Index of adults throughout the state. Mapping the data enables researchers to track patterns and pinpoint problems down to the neighborhood or even block level.

You might call it new food for thought.

Analysts can drill down into the data to assess whether public policies such as bike paths, bus routes and healthier school lunches can stem the rising tide of obesity that threatens to cut short many area residents’ lives, including a whole generation of children.

“Obesity prevention is a top priority in public health these days, and up until now, we only had data at the county level,” says Daniel Morris, a former state epidemiologist who spearheaded the driver’s license project.

Much like entry-level drugs and alcohol, being overweight can be a gateway to more severe problems such as diabetes, heart attacks, strokes, a poorer quality of life and shorter lifespan.

The Coalition for a Livable Future used the driver’s license data from Morris’ project to create a series of interactive maps, enabling researchers and policy analysts to try to correlate pockets of overweight people with other factors such as ethnicity, income, and access to parks, fresh and healthy food and transit.

One clear pattern emerged that everyone expected: People with higher incomes and more education are more likely to have their weight in a healthier range, while those with lower incomes and less schooling are more prone to being overweight and obese.

“I think the patterns are really striking, how strong the associations are between BMI and the indicators of socioeconomic status,” Morris says.

Others found a strong affirmation for what the city of Portland calls “20-minute neighborhoods,” generally closer-in areas where residents can walk or bike easily to fill most of their essential needs.

“It suggests a strong correlation between the ability to have a healthy weight and factors in our community: access to transit, having food, parks, walkable neighborhoods, etc.,” says Mara Gross, executive director of the Coalition for a Livable Future. “Maps are a good way to visualize data,” Gross says.

“I think the most striking thing about the map is the consistency and the pattern that it shows that the lowest BMI tends to be closer to the urban core of the region,” says Kris Smock, project manager for the coalition’s mapping project, known as the Regional Equity Atlas 2.0.

Residents of affluent suburbs like Lake Oswego and West Linn tend to have lower average weights, in contrast to those in blue-collar suburbs like Aloha and Cornelius.

But could some of the disparities be because of, say, the lack of good bus service in some parts of Washington County? Or more time spent in cars for residents of Sherwood and Oregon City, who tend to have higher BMIs?

“People who take a bus have an average of a 10-minute walk on either side of that,” says Michelle Kunec-North, a program coordinator at the Portland Bureau of Planning and Sustainability, who is evaluating health factors for that city’s rewrite of its comprehensive plan. That means people taking a bus get an average of 20 minutes’ exercise per weekday that those driving to work don’t get.

“Every hour in a day you spend in a car, your obesity risk goes up 6 percent,” Morris says.

Do communities like Cornelius and Fairview score on the heavy side because of their income levels? Or can some of that be traced to their high Hispanic population, whose ethnic diet is rich in tortillas and lard?

Researchers can now probe for answers to such questions by overlaying the maps in the new Regional Equity Atlas 2.0, released in June.

How they did it

Health researchers caution that BMI isn’t a perfect way to evaluate a healthy weight, and stress that the new maps are a simplified measure of the obesity problem. They can only illustrate things associated with an average weight level in an area, not the causes, says Betsy Clapp, research analyst with Multnomah County Health Department.

The maps show averages, anyway, and everyone is unique. A variety of factors contribute to obesity, including genes, income, ethnicity, education level, habits and factors in their community and lifestyle.

But the maps are the best available data right now. And Oregon is the first state in the nation to publish statewide BMI maps, Morris says.

Body Mass Index is a ratio based on a person’s weight and height. A rough standard set by the World Health Organization in 1995 deemed a BMI higher than 25 as overweight, and a BMI higher than 30 as obese.

The map numbers also have to be taken with a grain of salt because many peoples’ weights reflected on their driver’s licenses are no longer accurate — or never were. Studies show that women under-report their weight at the Department of Motor Vehicles by 5 percent on average, and men under-report it by 2 percent on average, Morris says.

Researchers did not adjust the data in the maps to reflect that, though, because what they hope to show is patterns.

No individual’s personal data is being released, and the public won’t be able to examine data for a tiny area, such as a block with five residents, for fear someone could glean an individual’s data from that.

Aha moments

Initial review of the maps appears to confirm that what the public health sector calls “healthy eating, active living” seems to correlate with better BMIs.

Researchers hope to explore patterns showing BMI levels one wouldn’t ordinarily expect, much as a low-income school with high test scores can provide useful insights for educational improvements.

“It can be a real ‘aha’ moment, and can open up the conversation to more people, more solutions,” says Noelle Dobson, associate director of the nonprofit Oregon Public Health Institute.

The Coalition for a Livable Future released an initial Regional Equity Atlas in 2007, which focused more on features in the built environment such as parks. That was used by Metro, Gross says, to prioritize areas lacking in natural areas when it awarded Nature in Neighborhoods grants.

The new atlas adds a whole new layer of health data, such as on asthma and BMI.

To view the new maps, and download free software to analyze them, visit

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