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 µM (PM2.5), nitrogen dioxide (NO2) 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 ß* = -0.13, BC ß* = -0.15, PM2.5 ß* = -0.16, all p < 0.001). Leptin was associated with green space in a 100 m radius around the residence (ß* = -0.11; p = 0.002). Ghrelin was associated with negative emotions (active ghrelin ß* = -0.16; p = 0.04, total ghrelin ß* = -0.23; p = 0.0051) and happiness (active ghrelin ß* = 0.25; p < 0.001, total ghrelin ß* = 0.26; p < 0.001). Furthermore, total ghrelin levels were associated with the multi-exposure score, reflecting unhealthy exposures and lifestyle (ß* = -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.

Exposure to Residential Green Space and Bone Mineral Density in Young Children.

Importance: Bone mass accrual is influenced by environmental and lifestyle factors. Targeted interventions at the early stages of life might decrease fracture and/or osteoporosis risk later in life. Objective: To investigate whether early-life exposure to residential surrounding green space is associated with a change in bone mineral density in young children. Design, Setting, and Participants: In this prospective birth cohort study (ENVIRONAGE [Environmental Influence on Aging in Early Life]), mother-child pairs from Flanders, Belgium, were recruited at birth and followed up for 4 to 6 years, between October 1, 2014, and July 31, 2021. Data analysis was conducted between January and February 2022. Exposures: Green space was estimated for high green (>3 m vegetation height), low green (≤3 m vegetation height ), and total green (sum of high and low) within several radii (100-3000 m) around the residence after geocoding of the addresses. Main Outcomes and Measures: Radial bone mineral density was assessed using quantitative ultrasound measurement at follow-up, measured as the mean of the axially transmitted speed of sound in meters per second. Multiple linear and logistic regression models were used while accounting for relevant covariates and potential confounders. Results: The study population comprised 327 children (180 [55.0%] female; mean [SD] age, 4.6 [0.4] years at the follow-up evaluation). Early-life exposure to residential green space was associated with increased childhood bone health. An IQR increment in total green (21.2%) and high green (19.9%) space within 500 m was associated with an increase of 27.38 m/s (95% CI, 9.63-45.13 m/s) and 25.30 m/s (95% CI, 7.93-42.68 m/s) in bone mineral density, respectively. Additionally, an IQR increase in total (25.2%) and high (23.2%) green space within 1000 m was associated with a 67% (odds ratio, 0.33; 95% CI, 0.17-0.61) and 61% (odds ratio, 0.39; 95% CI, 0.18-0.75) lower risk of having a bone density lower than the sex-specific 10th percentile (3567.6 m/s for girls and 3522.8 m/s for boys). Conclusions and Relevance: In this study of children aged 4 to 6 years, higher bone mineral density and a lower risk of having low bone density were associated with higher residential green space exposure during childhood. These findings highlight the importance of early-life exposure to residential green space on bone health during critical periods of growth and development, with long-term implications.