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Updated: Jun 1, 2026
Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
Longitudinal analysis of sleep in relation to BMI and body fat in children: the FLAME study
Philippa J Carter1, Barry J Taylor, Sheila M Williams
1Department of Women's and Children's Health, University of Otago, Dunedin, New Zealand.
Insights
Insufficient sleep in young children increases their risk of becoming overweight. This weight gain is primarily due to increased fat mass, not lean mass, even after accounting for initial weight and other factors.
Area of Science:
- Pediatric obesity research
- Sleep science
- Childhood development
Background:
- Childhood obesity is a growing public health concern.
- Sleep duration is a modifiable behavior in children.
- Understanding factors influencing childhood weight is crucial.
Purpose of the Study:
- To investigate the association between reduced sleep duration and body composition in young children.
- To determine if sleep duration predicts the risk of becoming overweight in early childhood.
Main Methods:
- Longitudinal study tracking 244 children from age 3 to 7 years in Dunedin, New Zealand.
- Body composition (BMI, fat mass, fat-free mass) measured using bioelectrical impedance and DXA.
- Sleep duration, physical activity, diet, and family factors assessed via accelerometry and questionnaires.
Main Results:
- Each additional hour of sleep at ages 3-5 was linked to a significant reduction in Body Mass Index (BMI) at age 7.
- Reduced sleep was associated with a lower risk of being overweight (BMI ≥ 85th percentile).
- Observed BMI differences were primarily attributed to increased fat mass, not fat-free mass.
Conclusions:
- Young children with insufficient sleep face a higher risk of developing overweight conditions.
- The association between sleep and weight remains significant even after controlling for confounding variables.
- Weight gain in sleep-deprived children is characterized by increased fat deposition.
Objectives:
To determine whether reduced sleep is associated with differences in body composition and the risk of becoming overweight in young children.
Design:
Longitudinal study with repeated annual measurements.
Setting:
Dunedin, New Zealand.
Participants:
244 children recruited from a birth cohort and followed from age 3 to 7.
Main Outcome Measures:
Body mass index (BMI), fat mass (kg), and fat free mass (kg) measured with bioelectrical impedance; dual energy x ray absorptiometry; physical activity and sleep duration measured with accelerometry; dietary intake (fruit and vegetables, non-core foods), television viewing, and family factors (maternal BMI and education, birth weight, smoking during pregnancy) measured with questionnaire.
Results:
After adjustment for multiple confounders, each additional hour of sleep at ages 3-5 was associated with a reduction in BMI of 0.48 (95% confidence interval 0.01 to 0.96) and a reduced risk of being overweight (BMI ≥ 85th centile) of 0.39 (0.24 to 0.63) at age 7. Further adjustment for BMI at age 3 strengthened these relations. These differences in BMI were explained by differences in fat mass index (-0.43, -0.82 to -0.03) more than by differences in fat free mass index (-0.21, -0.41 to -0.00).
Conclusions:
Young children who do not get enough sleep are at increased risk of becoming overweight, even after adjustment for initial weight status and multiple confounding factors. This weight gain is a result of increased fat deposition in both sexes rather than additional accumulation of fat free mass.
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