Tuesday, July 11, 2017

Cellphones Used for Largest Ever Study of Physical Activity #Science #Health #Obesity

Using a larger dataset than for any previous human movement study, National Institutes of Health-funded researchers at Stanford University in Palo Alto, California, have tracked physical activity by population for more than 100 countries. Their research follows on a recent estimate that more than 5 million people die each year from causes associated with inactivity.

The large-scale study of daily step data from anonymous smartphone users dials in on how countries, genders, and community types fare in terms of physical activity and what results may mean for intervention efforts around physical activity and obesity. The study was published July 10, 2017, in the advance online edition of Nature.

Science Daily:  Smartphone data used in global study of physical activity

Likely you're aware America and Mexico toggle for the world lead in which country, on average, has the fattest people.  From that knowledge, it probably will come as no surprise there's a great deal of inactivity in America.

This should quell any reservations about sample sizes.

In their study, Scott L. Delp, Ph.D., James H. Clark Professor of Bioengineering and director of the Mobilize Center at Stanford University, and colleagues analyzed 68 million days of minute-by-minute step recordings from 717,527 anonymous users of the smartphone app. Participation spanned 111 countries, but the researchers focused their study on 46 countries, each with at least 1,000 users. Of those, 90 percent of users were from 32 high income countries and 10 percent were from 14 middle income countries. The Stanford Mobilize Center is an NIH Big Data 2 Knowledge Center of Excellence.

- SD

One of their observations:

The researchers report that countries with greater activity variation also have a larger proportion of inactive women. They found that in countries where activity is more uniform among members of the population, such as Japan, males and females are similarly active. But in countries with greater activity disparity, such as Saudi Arabia and the United States, there is disproportionately reduced activity for females. In fact, the gender gap accounts for 43 percent of activity inequality in those countries, according to the authors. They also found that the prevalence for obesity increases faster for females than males as population-wide activity decreases.

- SD

Before getting too wild about that, we don't see in it the reason there is a disproportionate reduction in activity for females in America.

Here's one possible reason:

The researchers investigated the idea that making improvements in a city's walkability -- creating an environment that is safe and enjoyable to walk -- could reduce activity inequality and the activity gender gap.

"If you must cross major highways to get from point A to point B in a city, the walkability is low; people rely on cars," Delp said. "In cities like New York and San Francisco, where you can get across town on foot safely, the city has high walkability."

Data from 69 U.S. cities showed that higher walkability scores are associated with lower activity inequality. Higher walkability is associated with significantly more daily steps across all age, gender, and body-mass-index categories. However, the researchers found that women recorded comparatively less activity than men in places that are less walkable.

- SD

Fort Worth has low walkability although it's better in the relatively small downtown area.  Overall the city is sprawled over a large area and walking is not a practical solution for much of anything.

In general the article confirms intuitive knowledge you had already insofar as not much activity means you will likely gain weight.  Even so, it does confirm the relationship if not the actual causation.

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