Mixture Effects of Commonly Applied Herbicides on County Level Obesity Rates in the United States: An Exploratory...

Area of Science:

• Environmental Health
• Toxicology
• Epidemiology

Background:

• Global rise in metabolic disorders like obesity presents a significant public health challenge.
• Emerging evidence suggests herbicide exposure may contribute to metabolic dysfunction.
• Limited research exists on the population-level impact of herbicide mixtures on obesity.

Purpose of the Study:

• To investigate the association between common herbicide applications and county-level obesity rates in the U.S.
• To assess the combined effects of multiple herbicide exposures on obesity.
• To explore variations in these associations based on geographic factors like rurality.

Main Methods:

• Utilized county-level data from 2013-2018 for 13 commonly applied herbicides.
• Employed adjusted single-pollutant mixed-effects models and quantile-based g-computation mixture modeling.
• Controlled for demographic, socioeconomic covariates, and geographic clustering.

Main Results:

• Significant positive associations found between obesity rates and individual herbicides like glyphosate, 2,4-D, and atrazine.
• Herbicide mixtures showed a significant positive association with higher obesity rates (Psi = 0.71).
• Glyphosate, 2,4-D, metolachlor, dimethenamid-P, and glufosinate were key contributors to the mixture effect.
• Associations were stronger in rural counties, especially in micropolitan regions.

Conclusions:

• Cumulative herbicide mixture exposure, not just individual chemicals, is crucial for understanding obesity risks.
• Observed rural-urban disparities necessitate targeted public health strategies for vulnerable rural populations.
• Findings underscore the need for policies addressing the metabolic impacts of herbicide mixtures.