Bullying is linked to increased BMI, new study shows

Wednesday, August 5, 2020
Young adult hangs head in arms.

New research shows that while both young men and young women saw an increase in Body Mass Index (BMI) one year after bullying occurred in high school, young men were more affected than young women.

Being a victim of bullying was associated with increased odds of going from a normal weight status to an overweight or obese status by 51 percent for females and 60 percent for males, says Nour Hammami, a School of Public Health and Health Systems PhD graduate who co-led the study.

“For males, victimization one year earlier was associated with higher odds of high weight status in the second year, even though no victimization was reported in the second year,” says Hammami. “For females, bullying at both the first and second years was seen to be associated with higher weight status at the second year.”

“Our results suggest that there are possibly different hidden coping mechanisms adopted by gender groups when faced with bullying,” says co-author Ashok Chaurasia, a School of Public Health and Health Systems professor. “It is crucial to understand these mechanisms and how different gender groups can be empowered to make healthy individual choices to use as coping mechanisms for bullying and improving self-health.”

The study found that youth who are victims of bullying were more physically active, but that they also engaged in more substance use, such as binge drinking behaviours, cannabis use and smoking than non-victims.

“When it comes to policy or interventions to better the health of a population, multifaceted interventions may be preferred for greater effectiveness,” Chaurasia says. “Such an approach is more reflective of human behaviour, where there is dependency among individual choices.”

“The implications of this study are that youth who are victims of bullying have negative psychosocial effects as a result of their victimization, that they also engage in more problem and risky health behaviours and that this is associated with other adverse health effects such as increases in weight status,” says Hammami. 

“Rather than focus the attention on encouraging youth to lose weight, as has been the case in previous obesity prevention models, we must understand the causes and predictors of increases in weight status and work with schools and policy-makers to address these factors through prevention and intervention programs.”

Hammami says that bullying prevention should include disciplinary action for perpetrators, more supervision of student common areas by teachers and encouraging student bystanders to speak up when they witness bullying. “We also recommend that physical activity be a focal point as it is a behaviour that enhances one’s physical and mental health and has been seen to be effective in combating bullying by fostering comradery and team engagement among youth.”

The data came from more than 4,500 Ontario high school youth collected over three years using the COMPASS study, a youth behavioural patterns survey that is administered to schools across Canada. Data did not exist for non-binary genders.

The study, “Exploring gender differences in the longitudinal association between bullying and risk behaviours with Body Mass Index among COMPASS youth in Canada,” was published in Preventive Medicine, and was co-authored by Nour Hammami (now at McGill University), Ashok Chaurasia (Waterloo), Philip Bigelow (Waterloo) and Scott Leatherdale (Waterloo).