The implications of the coronavirus disease (COVID-19) lockdown measurements and social isolation in children and their parents are still unknown. The aims of this study were to examine the impact of COVID-19 lockdown on emotional state, feelings and lifestyle of children and their parents, to explore the association between parental characteristics and child well-being and to examine whether the impact of lockdown depends on socio-economic status. Parents completed an online survey including data about socio-demographic information, parent and child feelings and lifestyle during lockdown. Logistic regression and correlation analysis were used to establish associations between variables. In total, 814 parents with children between 4 and 11 were included in the study. According to parents, 69.5% of the children showed changes in their emotional state, 55.3% altered their routine and 62.6% showed sleep disorders. Families with lower socio-economic status were more worried about health, shortage of food and household income (p < 0.01). Parent and children concern about food/essential items were highly associated [OR (CI 95%) 13.0 (6.81, 26.5), p < 0.01]. Adverse children's emotional state was associated with parental feeling of loneliness (r = 0.35) and inversely associated with keeping a routine (r = −0.11). Sleep changes were inversely associated with keeping a routine and having a balcony/garden (r = −0.53 and −0.16). We conclude that lockdown affected emotional state and lifestyle of children and parents, which were strongly related. Routine and positive parental attitude supported children's well-being. Economic issues were an important concern in families with lower socio-economic status. Our findings can help to promote child health during lockdown.

Background Further investigation is needed to define the impact of long-term pandemic lockdown in children. Objectives To examine changes in body mass index z-score (zBMI), lifestyle, Health-Related Quality of Life and proportion of overweight or obesity (OW/OB) in 6- to 9-year-old children in Argentina. Methods Observational study with baseline measurements prior to lockdown and follow-up after eight months of strict restrictive measures (November 2020, first visit, n = 144) and after ten months of partial reopening (September 2021, second visit, n = 108). Anthropometric changes from baseline to first visit in lockdown group (LG) were compared with a historical control group (HCG, n = 134). Follow-up visits included anthropometric measures, lifestyle questionnaire and Pediatric Quality of Life Inventory. Results Change in zBMI was higher in LG [median, IQR: 0.46 (−0.00; 0.83)] vs HCG [median, IQR: 0.02 (−0.31; 0.27)]; p < 0.001, particularly in children with pre-existing OW/OB. In LG, zBMI was higher at first and second visit vs baseline ( p < 0.001) and in second visit vs first visit for boys ( p = 0.037) but not for girls. The proportion of children with OW/OB increased from baseline (43.5%) to first (56.5%) and second visit (58.3%) ( p = 0.029). Unlike girls, the proportion of boys with OW/OB increased from baseline to first and second visit ( p = 0.045). Change in zBMI was higher in children with less healthy habits ( p < 0.001). Conclusions Weight gain continued to increase in boys when lockdown measurements were eased, although sedentary behaviors decreased and quality of life improved, indicating that the effects of pandemic lockdown could be difficult to reverse.