RESUMO
INTRODUCTION: The monitoring of children's growth plays a crucial role in assessing their growth patterns and indicating their weight status. Overweight and obesity, determined by cut-offs of body mass index (BMI), are most commonly associated with unhealthy nutrition, non-communicable diseases, and other health disorders. The World Health Organization (WHO) initiated the WHO European Childhood Obesity Surveillance Initiative (COSI) to measure routinely trends in children's anthropometric changes, which allow intercountry comparisons within the European Region. Lithuania joined the COSI initiative. Our study aims to evaluate and compare underweight, normal and elevated weight (overweight and obesity) changes of Lithuanian first-graders during eleven years period. METHODS: This study was composed according to the COSI study protocol, and it compares the five rounds of anthropometric measurements of Lithuanian first-graders (7-8-year-old) from 2008 to 2019. The main analysed variables were weight and height; calculated BMI, weight-for-age (W/A), height-for-age (H/A) and body mass index-for-age (BMI/A) z-scores. Changes of the indicators were evaluated according to the International Obesity Task Force (IOTF) cut-offs and WHO child growth standards, grouped by 4 estimates: underweight (thinness), normal weight, overweight and obesity. All comparisons were performed between age groups, gender and COSI round year. RESULTS: The mean values for weight, height, W/A and H/A Z-scores were significantly higher for both age and gender groups when comparing later COSI round years (2016 or 2019) to earlier years (2008-2013, in some cases 2016 is included in this range). Time trends of the WHO growth standards and IOTF cut-offs indicate significant decrease among 7-year-old overweight group for boys and girls. Also, a significant decrease was indicated among boys aged 8 years in the overweight group according to the WHO definitions. The only significant increase in trend were expressed in girl's group with obesity aged 8 years according to IOTF cut-offs. CONCLUSION: The prevalence of overweight and obesity of first-grade children in Lithuania indicates positive changes, that is the proportion of children with elevated body weight decreased, during eleven-year period. However, it is important to continue the monitoring of children's growth tendencies.