Link between ozone exposure and the development of type 2 diabetes

Older Californians who live in communities with poor air quality, even those who exercise, as recommended, but do so outdoors, have a higher risk of type 2 diabetes, a complex and chronic metabolic disorder caused by insulin resistance and cellular dysfunction.

Although the development of diabetes is generally linked to obesity and physical inactivity, its causes are complex; recent research has suggested that environmental risk factors, including air pollution, also play a major role, said Dr Beate Ritz, professor of epidemiology and environmental health sciences at the Fielding School of Public Health of UCLA who studied the impact of ozone (O₃), a common element of air pollution, on human health.

“The O₃The risk of diabetes was 1.5 times higher in the highest outdoor activity group, and even in the low activity group there is a visibly higher risk compared to those who live in less polluted communities, ”said Ritz, co-author of“ Physical activity is well known and widely recognized for its health benefits, but the beneficial effects of outdoor physical activity on human health may need to be weighed against the adverse effects of air pollution in areas affected by high pollution levels. “

The study, published in the September edition of the peer-reviewed journal Environmental health perspectives.

The researchers, from four different University of California campuses (UCLA, Berkeley, Irvine, and San Francisco), focused on residents of a six-county area surrounding Sacramento, all older Mexican-Americans (60 years and more) who registered in the Sacramento area. Latino Study on Aging, or SALSA. The counties include Placer, Sacramento, Solano, Sutter, Yolo, and Yuba, although researchers say the increased vulnerabilities are not limited to the region or those interviewed.

“Mexican Americans are the fastest growing segment of the American population, have a high prevalence of diabetes, and are also among the populations most exposed to air pollution in California,” said Dr. Mary N. Haan, professor emeritus at the University of California, San Francisco, and principal investigator of the SALSA study, which began in 1998.₃ exposure and diabetes, or assessed whether outdoor physical activity alters associations between O₃ and diabetes in this population.

The researchers looked at the health information recorded during the surveys, which continued until 2007 on a regular basis, as well as pollution, air quality and traffic levels in the same neighborhoods. They found that out of nearly 1,800 people surveyed, 186 new diabetes developed.

“Although epidemiological evidence is limited, experiments suggest that ozone exposures can induce insulin resistance, which contributes to diabetes,” said Dr Yu Yu, a researcher at the Fielding School and co- author of the study. “In turn, laboratory experiments have shown that people who exercise outdoors and thus breathe more heavily, when exposed to ozone, can be adversely affected due to the increased inhalation of the atmospheric pollution.”

People who developed diabetes lived in communities with higher exposure to ozone, and those who were more likely to exercise outdoors, defined as gardening and gardening, walking, swimming or dancing; hunting, camping and boating; and outdoor sports, including golf, were more at risk.

“Unfortunately, what this clearly shows is that even Californians who are doing the right thing about health and wellness are at risk for diabetes due to poor air quality,” he said. said Dr. Jason G. Su, co-author and co-author. researcher at the University of California at Berkeley. “These findings are of great relevance to the protection of public health. Policies and strategies are needed to reduce ozone exposure in communities to ensure that the health benefits of physical activity are not diminished by exposure to pollution, especially in vulnerable populations. “

Methods :

The team analyzed the health histories of more than 1,000 Mexican-American participants in the Sacramento Area Latino Study on Aging (SALSA), conducted from 1998 to 2007. Ambient ozone (O₃) Exposure levels were modeled with a land use regression constructed with saturation monitoring data collected from 49 sites in Metro Sacramento. Using proportional hazards models, the researchers estimated the risk of developing incident diabetes based on an average O₃ exposure modeled over 5 years before incident diabetes diagnosis or last follow-up. Additionally, the team investigated whether higher or lower levels altered the association between O₃ exposure and diabetes.

Provided by UCLA Fielding School of Public Health