New research suggests that weight gain patterns during childhood might be the missing link between exposure to air pollution and an increased risk of developing insulin resistance – a key early sign of type 2 diabetes – in young adults.
Previous research has suggested that traffic-related air pollution can negatively affect children’s glucose metabolism – how their bodies process and use sugar for energy – which in turn can lead to insulin resistance. In this study, a team from the Keck School of Medicine set out to find if weight gain over time can explain this link.
The team focused on a group of 282 young adults, about 24 years old, and measured two key indicators of blood sugar control: insulin resistance and HbA1c (a marker of average blood sugar levels over time).
They also tracked participants’ body mass index (BMI) from childhood.
They found that children who were exposed to higher levels of nitrogen oxides (NOx) had higher BMI at age 13 and higher levels of insulin resistance as young adults. In fact, for every standard increase in air pollution exposure during childhood, participants showed a noticeable increase in both their weight as teenagers and their insulin resistance later in life.
The study found that about 42% of the effect of air pollution on insulin resistance could be explained by weight gain.
While there is still some uncertainty over exactly how pollution affects metabolism, one explanation put forward is that air pollution triggers inflammation in the body, which can disrupt fat storage and insulin function.
Fangqi Guo, PhD, MPH, postdoctoral scholar research associate in the Department of Population and Public Health Sciences at Keck School of Medicine, and lead author of the study said: ‘We estimated about 42% of the relationship between early pollution exposure and insulin resistance can be explained by accelerated BMI growth trajectories – which describes how an individual’s BMI changes over time – and further contributes to insulin resistance, a key risk factor for type 2 diabetes.
‘Our discovery is especially important for families and children living in high-traffic urban areas who may already face other socioeconomic or health disparities By identifying weight gain during adolescence as a key pathway between air pollution exposure and insulin resistance, our research underscores the importance of early interventions. These include promoting healthy lifestyle habits and weight management and improving air quality—in a bid to reduce the risk of chronic disease later in life.
‘Public health efforts that address both environmental exposures and childhood obesity could make a significant impact.’
The full research can be read here.
Photo: Annushka Ahuja
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