Exploring the Impact of Lifestyle and Environmental Exposures on Appetite Hormone Levels in Children and Adolescents: an Observational Study

Background: Appetite hormones are considered a promising target in fighting obesity as impaired appetite hormone levels have already been associated with obesity. However, further insights in the drivers of appetite hormone levels are needed. Objectives: In this study, we investigated the associations of fasting appetite hormone levels with lifestyle and environmental exposures in children and adolescents. Methods: A total of 534 fasting blood samples were collected from children and adolescents (4-16y,50% boys) and appetite hormone levels (glucagon-like peptide-1 (GLP-1), peptide YY (PYY), pancreatic polypeptide (PP), leptin and ghrelin) were measured. Exposures included dietary quality (fiber-rich food intake, sugar propensity, fat propensity), psychosocial stress (happiness, negative emotions, negative life events and emotional problems), sleep duration, physical activity and environmental quality (long term black carbon (BC), particulate matter <2.5 M (PM2.5), 2.5 ), nitrogen dioxide (NO2) 2 ) exposure, and green space in a 100 m and 2000 m radius around the residence). A multi-exposure score was calculated to combine all the exposures at study in one measure. Associations of individual exposures and multi-exposure score with appetite hormone levels were evaluated using linear mixed regression models adjusting for sex, age, socioeconomic status, waist-to-height ratio and multiple testing. Results: GLP-1 was associated with air pollution exposure (NO2 2 (3* =-0.13, BC (3* =-0.15, PM 2.5 (3* =-0.16, all p < 0.001). Leptin was associated with green space in a 100 m radius around the residence ((3* =-0.11; p = 0.002). Ghrelin was associated with negative emotions (active ghrelin (3* =-0.16; p = 0.04, total ghrelin (3* =-0.23; p = 0.0051) and happiness (active ghrelin (3* = 0.25; p < 0.001, total ghrelin (3* = 0.26; p < 0.001). Furthermore, total ghrelin levels were associated with the multi-exposure score, reflecting unhealthy exposures and lifestyle ((3* =-0.22; p = 0.036). Discussion: Our findings provide new insights into the associations of exposures with appetite hormone levels, which are of high interest for preventive obesity research. Further research is crucial to reveal the underlying mechanisms of the observed associations.