Mixture Analysis of Associations between Occupational Exposure to Polycyclic Aromatic Hydrocarbons and Sperm Oxidative DNA Damage.

OBJECTIVE: This study aimed to determine (i) associations between levels of the polycyclic aromatic hydrocarbon (PAH) mixture with 16 targeted PAH compounds in the personal breathing zone area and sperm oxidative DNA damage, (ii) associations between levels of individual PAH compounds and sperm oxidative DNA damage, (iii) oxidative stress as the mode of action for the genotoxic effects on sperm, and (iv) any dose-response relationship between exposure to the PAH mixture and/or individual PAH compounds and sperm oxidative DNA damage. METHODS: Sixteen targeted PAH compounds in the personal breathing zone area of 38 coke-oven workers and 24 control subjects were quantified using gas chromatography-mass spectrometry. Sperm oxidative damage and status were evaluated by measuring levels of sperm 7,8-dihydro-8-oxoguanie (8-oxodGuo), seminal malondialdehyde (MDA) and seminal reactive oxygen species (ROS). Bayesian kernel machine regression with hierarchical variable selection process was employed to determine associations of the PAH mixture and the biomarkers of sperm oxidative damage. A novel grouping approach needed for the hierarchical variable selection process was developed based on PAH bay region and molecular weight. RESULTS: The PAH mixture exhibited a positive trend with increased sperm 8-oxodGuo levels at their lower percentiles (25th-50th). The exposure of the PAH mixture was associated with increased MDA levels in sperm. Bay and bay-like regions of the PAH mixture were the most important group for estimating the associations between the PAH mixture and sperm oxidative stress status. Benzo[a]anthracene was the main individual PAH compound that was associated with increased MDA levels. CONCLUSION: Sperm oxidative DNA damage induced by occupational exposure to the PAH mixture had a suggestive association with increased MDA levels in coke-oven workers. Finally, the study identified that the individual PAH compound, benzo[a]anthracene, was the primary driver for the suggestive association between the PAH mixture and sperm oxidative damage.

Time trends of overweight and obesity among schoolchildren in Kuwait over a 13-year period (2007-2019): repeated cross-sectional study.

OBJECTIVES: This study aimed to examine age-specific trends in the prevalence of overweight and obesity in schoolchildren in Kuwait over a 13-year period (2007 to 2019) using the WHO, the Centers for Disease Control and Prevention (CDC) and the International Obesity Taskforce (IOTF) definitions. DESIGN: Using cross-sectional approach, Kuwait Nutrition Surveillance System (KNSS) objectively measured weight and height of schoolchildren over a 13-year period. Log-binomial regression models were used to examine age-specific trends of obesity and overweight over the study period. SETTING: Public primary, middle and high schools in all provinces of Kuwait. PARTICIPANTS: Schoolchildren aged 5-19 years (n 172 603). RESULTS: According to the WHO definition, the prevalence of overweight and obesity in schoolchildren, respectively, increased from 17·73 % and 21·37 % in 2007 to 20·19 % and 28·39 % in 2019 (Pfor trend < 0·001). There is evidence that the obesity in females (but not males) has levelled off in the period 2014-2019 according to the three definitions of obesity, which is corroborated by a similar trend in the mean of BMI-for-age Z-score. CONCLUSION: The prevalence of obesity and overweight in schoolchildren in Kuwait has risen over the last 13 years and trends are similar across all definitions. Obesity is no longer increasing at the same pace and there is evidence that the prevalence of obesity in females has plateaued. The current level of childhood overweight and obesity is too high and requires community-based and school-based interventions.