It is a well-established fact that weight issues can affect a child’s physical and emotional health, but it is also true that body weight alone is not the sole determinant of a child’s mood and behavior. Many other factors such as genetics, environment, nutrition, and life events can impact a child’s mental and emotional well-being. Therefore, it is important to approach the issue of childhood weight holistically and address all potential factors that may contribute to a child’s mental and emotional health.
According to a study published in eLife, childhood BMI is unlikely to have a significant impact on children’s mood or behavioral disorders. The findings suggest that previous studies that found a strong link between childhood obesity and mental health may have overlooked family genetics and environmental factors.
Obese children are more likely to have depression, anxiety, or attention deficit hyperactivity disorder (ADHD). However, the nature of the link between obesity and these mental health conditions is unclear. Obesity may exacerbate mental health symptoms or vice versa. Alternatively, the environment of a child may contribute to both obesity and mood and behavioral disorders.
Overall, the influence of a parent’s BMI on a child’s mental health seems to be limited. As a result, interventions to reduce parents’ BMIs are unlikely to have widespread benefits to children’s mental health.
Alexandra Havdahl
“We need to better understand the relationship between childhood obesity and mental health,” says lead author Amanda Hughes of Bristol Medical School, University of Bristol, UK. “This necessitates disentangling the contributions of child and parent genetics as well as environmental factors affecting the entire family.”
Hughes and colleagues looked at genetic and mental health data from 41,000 eight-year-old children and their parents from the Norwegian Mother, Father, and Child Cohort Study and the Norwegian Medical Birth Registry. They looked at the relationship between children’s body mass index (BMI) – a weight-to-height ratio and symptoms of depression, anxiety, and ADHD. They also took parental genetics and BMI into account to help separate the effects of the children’s genetics from the influence of other factors that affect the entire family.
The analysis found a minimal effect of a child’s own BMI on their anxiety symptoms. There was also conflicting evidence about whether a child’s BMI influenced their depressive or ADHD symptoms. This suggests that policies aiming to reduce childhood obesity are unlikely to have a big impact on the prevalence of these conditions. “At least for this age group, the impact of a child’s own BMI appears small. For older children and adolescents, it could be more important,” says Neil Davies, Professor at University College London, UK.
When they looked at the effect of the parents’ BMI on the children’s mental health, the team found little evidence that the parents’ BMI affected children’s ADHD or anxiety symptoms. The data suggested that having a mother with a higher BMI might be linked with depressive symptoms in children, but there was little evidence of any link between the child’s mental health and the father’s BMI.
“Overall, the influence of a parent’s BMI on a child’s mental health seems to be limited. As a result, interventions to reduce parents’ BMIs are unlikely to have widespread benefits to children’s mental health,” says Alexandra Havdahl, Research Professor at the Norwegian Institute of Public Health, Norway. Havdahl is a co-senior author of the study alongside Neil Davies and Laura Howe, Professor of Epidemiology and Medical Statistics at Bristol Medical School.
“Our results suggest that interventions designed to reduce child obesity are unlikely to make big improvements in child mental health. On the other hand, policies which target social and environmental factors linked to higher body weights, and which target poor child mental health directly, may be more beneficial,” Hughes concludes.
