Air pollution tips the scale for obesity in women

A graphic illustration of a city

New research from Michigan Public Health

Obesity has been a major global health issue in recent decades as more people eat unhealthy diets and fail to exercise regularly.

A new University of Michigan School of Public Health study suggests there is another factor that tips the scale in women's weight, body mass index (BMI), waist circumference, and body fat — air pollution. 

Late 40s/early 50s women exposed long-term to air pollution – specifically higher levels of fine particles, nitrogen dioxide, and ozone – saw increases in their body size and composition measures, said Xin Wang, research investigator in the Department of Epidemiology, in the University of Michigan School of Public Health and study's first author. 

Data came from 1,654 White, Black, Chinese, and Japanese women from the Study of Women’s Health Across the Nation. These women, whose baseline median age was nearly 50 years, were tracked from 2000 to 2008. 

Annual air pollution exposures were assigned by linking residential addresses with hybrid estimates of air pollutant concentrations. Researchers examined the associations between the pollution and the participants' body size and composition measures. One question the researchers sought to answer was whether these associations differed by physical activity.

Exposure to air pollution was linked with higher body fat, higher proportion fat, and lower lean mass among midlife women. For instance, body fat increased by 4.5 percent – or about 2.6 pounds.

Researchers explored the interaction between air pollution and physical activity on body composition. High levels of physical activity – which had been based on the frequency, duration and perceived physical exertion of more than 60 exercises –  was an effective way to mitigate and offset exposure to air pollution, the research showed.

Since the study focused on midlife women, the findings can't be generalized to men or women in other age ranges, Wang said. 

The study's co-authors and their affiliations were Carrie Karvonen-Gutierrez (Michigan Public Health), Ellen Gold (UC Davis), Carol Derby (Albert Einstein College of Medicine), Gail Greendale (UCLA), Xiangmei Wu (California Environmental Protection Agency), Joel Schwartz (Harvard), and Sung Kyun Park (U-M).

The findings appear in Diabetes Care.


Andrea LaFerleAndrea LaFerle

Director of Public Relations and Marketing
University of Michigan School of Public Health