|
 Researchers studied more than 1,000 Mexican-Americans living in
southern California and found short-term exposure to contaminated
air was linked to an increased risk of high cholesterol and impaired
processing of blood sugar – risk factors for diabetes.
Scientists aren’t exactly sure how air pollution might lead to
diabetes.
It’s possible that air pollution causes inflammation in the body,
which triggers a chain reaction that makes it harder for people to
process blood sugar, said senior study author Dr. Frank Gilliland,
director of the Southern California Environmental Health Sciences
Center and researcher at the Keck School of Medicine at the
University of Southern California in Los Angeles.
Some previous research has linked air pollution from traffic and
other sources to an increased risk of type 2, or adult-onset,
diabetes, which happens when the body can't properly use or make
enough of the hormone insulin to convert blood sugar into energy.
But few tests have been done in humans, the researchers note in the
journal Diabetes Care.
For the current study, Gilliland and colleagues examined
concentrations of ozone, an unstable form of oxygen produced when
various types of traffic and industrial pollution react with
sunlight; nitrogen dioxide, a byproduct of fossil fuel combustion
that can contribute to smog; and so-called PM 2.5, a mixture of
solid particles and liquid droplets smaller than 2.5 micrometers in
diameter that can include dust, dirt, soot and smoke.
All of these pollutants have been found to damage lungs and some PM
2.5 particles are small enough to enter the bloodstream, where they
have been linked to increased risk of heart disease and stroke.
All of the participants in the current study completed
questionnaires on their dietary and exercise habits, and they also
had lab tests to measure levels of cholesterol and sugars in their
blood.
The researchers also looked at what’s known as insulin resistance,
the body’s failure to respond to the hormone, which is a hallmark of
diabetes. Participants were around 35 years old on average and
typically overweight or obese. Many of them lived in low-income
neighborhoods and lacked any education beyond high school.
In addition, they all either had diabetes during pregnancy or were
related to a woman who did.
Even with this diabetes family history, people exposed to higher
levels of overall air pollution had greater levels of insulin
resistance, more sugars in their blood and higher cholesterol.
[to top of second column] |
Weight and body fat percentage explained a significant portion of
the connection.
Researchers did not find a connection between levels of
traffic-related nitrogen dioxide from freeways and risk factors for
diabetes. However, PM 2.5 exposure was significantly associated with
diabetes risk factors, with an effect equivalent to that of obesity,
the authors note.
Among the study’s limitations is that researchers lacked data on how
long people lived at their current address, which made it impossible
to assess lifetime exposure to air pollution.
Even so, the findings suggest people who live in cities and other
areas with poor air quality should take precautions, said Michael
Jerrett, director of the Center for Occupational and Environmental
Health at the University of California, Los Angeles.
Among other things, people could try to limit outdoor exercise
during peak commute hours to lower exposure to traffic fumes and try
not to run or ride a bike along a major highway, said Jerrett, who
wasn’t involved in the study.
Indoors, people should use what’s known as a high-efficiency
particulate air (HEPA) filter on furnaces or air conditioning units,
or buy stand-alone units for bedrooms, Jerrett said. These
mechanical filters force air through a fine mesh that can trap
harmful pollutants, but there’s a limit to how much individuals can
do, he said.
“Air pollution is an involuntary risk factor,” Jerrett said. “We all
breathe the air, and this should create a stronger incentive for
government to take action to reduce emissions that lead to air
pollution.”
SOURCE: http://bit.ly/22mZPxU Diabetes Care, online February 11,
2016.
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed. |
