5 ms·

"Data on how BMI in rural and urban populations is changing are needed to plan interventions that address underweight and overweight." Specifically in the U.S.

"Data on how BMI in rural and urban populations is changing are needed to plan interventions that address underweight and overweight." Specifically in the U.S., isn't it true that the population landscape is rapidly shifting from Rural => Urban? I intend to read more to see how this may/may not be a confounder in this type of temporal analysis. Tldr: If the rural population is decreasing, then your denominator is smaller and estimates of disease proportion would increase over time. These confounders are commonly addressed in systematic reviews - just haven't found it specifically in this one.

wutbrodo 7y ago
> Tldr: If the rural population is decreasing, then your denominator is smaller and estimates of disease proportion would increase over time. This wouldn't happen from the denominator decreasing per se, but from the emigrants being skewed healthy. Which is pretty plausible, given that you'd expect emigrants to skew eg younger.
- derefr 7y ago
  You would expect emigrants to be people who are productive enough to afford the increased costs-of-living of a city, which usually (but not always) implies health—at least insofar as severe unhealthy usually restricts productivity.
rayiner 7y ago
Yes and no. The Census Bureau defines "urban area" as contiguous census blocks with a density above 1000 people per square mile. That means many places that we'd call "suburban" or "exurban" are counted as "urban." During the 20th century, you saw two trends: movement from rural areas to urban areas, but simultaneous movement from cities to suburbs: https://www.researchgate.net/figure/Percentage-of-US-metropolitan-area-population-in-suburbs-1900-to-2000-by_fig1_258198169 https://www.researchgate.net/figure/Percentage-of-US-metropo.... Since 1920, we went from 35% of metro area residents living in suburbs to 70% in 2000. At the same time, the percentage of people living in "urban" areas went from 50% to 80%. A little back-of-the-napkin math suggest that what we think of as the "urban" population (people living in cities) shrank from ~35% in 1920 to 25% in 2000.
dcolkitt 7y ago
Agree with this observation. This might simply be a burn-off effect. Consider a simple model. Fact one: Obesity is disproportionately concentrated in the less-educated. Fact two: Urbanization is disproportionately concentrated in the highly-educated. Well, what we would see over time is faster rising obesity in rural areas than urban areas. But that's simply a manifestation of the sorting effect. The underlying populations (the educated vs. uneducated) have not fundamentally changed, just relocated. Without considering this we might be spuriously fooled into misunderstanding the causality of obesity. Under this model, rural living itself has absolutely nothing to do with rising obesity. It's merely serving as a proxy for a more important variable.
- deleted 7y ago
  [deleted]
csense 7y ago
Anecdotally, I feel like young, ambitious people are the most likely to leave rural / suburban areas for cities. If the younger, more health-conscious folks are likelier to leave, it makes sense the people left behind are older and less healthy.
falcolas 7y ago
> population landscape is rapidly shifting from Rural => Urban Perhaps percentage wise, but the overall population in America is going up as well. As a result, rural areas aren't really declining, the population increase is simply mostly happening in the urban areas. The rural area I live in is, instead, growing significantly (a rural definition of significantly) as people age out of urban areas and use the millions from their property sales in CA to purchase a summer home here.
- lotsofpulp 7y ago
  There are very large sections of the rural US in decline, in the northeast, midwest, and south. Far more than are growing, which are mostly in the Rocky Mountains and west of there.
Mountain_Skies 7y ago
Obesity also impacts the impoverish more than those financially better off. Gentrification is pushing many of these peop!e further and further out. The automobile focused design of the areas they move to combined with less access to private automobile ownership confines some of them to their homes with trips out being limited to only the most important errands as it costs money to hire transportation.

wutbrodo 7y ago

> Tldr: If the rural population is decreasing, then your denominator is smaller and estimates of disease proportion would increase over time. This wouldn't happen from the denominator decreasing per se, but from the emigrants being skewed healthy. Which is pretty plausible, given that you'd expect emigrants to skew eg younger.

derefr 7y ago
You would expect emigrants to be people who are productive enough to afford the increased costs-of-living of a city, which usually (but not always) implies health—at least insofar as severe unhealthy usually restricts productivity.

rayiner 7y ago

Yes and no. The Census Bureau defines "urban area" as contiguous census blocks with a density above 1000 people per square mile. That means many places that we'd call "suburban" or "exurban" are counted as "urban." During the 20th century, you saw two trends: movement from rural areas to urban areas, but simultaneous movement from cities to suburbs: https://www.researchgate.net/figure/Percentage-of-US-metropolitan-area-population-in-suburbs-1900-to-2000-by_fig1_258198169 https://www.researchgate.net/figure/Percentage-of-US-metropo.... Since 1920, we went from 35% of metro area residents living in suburbs to 70% in 2000. At the same time, the percentage of people living in "urban" areas went from 50% to 80%. A little back-of-the-napkin math suggest that what we think of as the "urban" population (people living in cities) shrank from ~35% in 1920 to 25% in 2000.

dcolkitt 7y ago

Agree with this observation. This might simply be a burn-off effect. Consider a simple model. Fact one: Obesity is disproportionately concentrated in the less-educated. Fact two: Urbanization is disproportionately concentrated in the highly-educated. Well, what we would see over time is faster rising obesity in rural areas than urban areas. But that's simply a manifestation of the sorting effect. The underlying populations (the educated vs. uneducated) have not fundamentally changed, just relocated. Without considering this we might be spuriously fooled into misunderstanding the causality of obesity. Under this model, rural living itself has absolutely nothing to do with rising obesity. It's merely serving as a proxy for a more important variable.

deleted 7y ago
[deleted]

csense 7y ago

Anecdotally, I feel like young, ambitious people are the most likely to leave rural / suburban areas for cities. If the younger, more health-conscious folks are likelier to leave, it makes sense the people left behind are older and less healthy.

falcolas 7y ago

> population landscape is rapidly shifting from Rural => Urban Perhaps percentage wise, but the overall population in America is going up as well. As a result, rural areas aren't really declining, the population increase is simply mostly happening in the urban areas. The rural area I live in is, instead, growing significantly (a rural definition of significantly) as people age out of urban areas and use the millions from their property sales in CA to purchase a summer home here.

lotsofpulp 7y ago
There are very large sections of the rural US in decline, in the northeast, midwest, and south. Far more than are growing, which are mostly in the Rocky Mountains and west of there.

Mountain_Skies 7y ago

Obesity also impacts the impoverish more than those financially better off. Gentrification is pushing many of these peop!e further and further out. The automobile focused design of the areas they move to combined with less access to private automobile ownership confines some of them to their homes with trips out being limited to only the most important errands as it costs money to hire transportation.