School year versus summer differences in child weight gain: a narrative review

Area of Science:

• Pediatrics
• Public Health
• Childhood Obesity Research

Background:

• High prevalence of childhood overweight and obesity is a significant public health concern.
• Schools are implicated in the complex causal chain of child obesity.
• Understanding seasonal variations in child adiposity is crucial for effective interventions.

Purpose of the Study:

• To analyze seasonal differences in child adiposity, physical activity, and sleep patterns.
• To investigate the relationship between these factors and childhood obesity.
• To identify research gaps for informing national policy.

Main Methods:

• Review of six longitudinal descriptive studies comparing school year and summer changes in child adiposity.
• Analysis of four physical activity intervention studies examining summer fitness loss.
• Examination of studies on physical activity and energy expenditure patterns during summer.

Main Results:

• Overweight/obese children showed accelerated weight/BMI gain during summer; healthy-weight children gained less.
• Fitness improvements during the school year were often lost over the summer.
• Seasonal patterns in physical activity and sleep duration require further clarification in relation to adiposity.

Conclusions:

• Seasonal differences in child adiposity are evident, with overweight children gaining more weight in summer.
• Physical activity is suggested as a primary factor, but documented PA patterns do not fully support this.
• Longitudinal research is needed to establish clear seasonal patterns in adiposity, physical activity, and sleep for both overweight and healthy-weight children to guide policy.