A research team from The Hospital for Sick Children (SickKids) has identified a link between paternal preconception body mass index (BMI) and zBMI, a measure of child weight, in children assigned male at birth. This study is one of the first to examine the relationship between preconception health factors in men and child growth, offering insight into an often-overlooked component of the family unit.

Published on Friday, February 3 in the International Journal of Obesity, the research team found higher paternal pre-conception BMI increased the odds of being overweight and obese uniquely in male children throughout early childhood. This risk significantly increased when the mother was classified as overweight pre-pregnancy.

“Research and preconception care have predominantly focused on the mother’s health and weight status,” says Dr. Catherine Birken, Staff Paediatrician and Senior Scientist in the Child Health Evaluative Sciences program and the Edwin S.H. Leong Chair in Child Health Intervention.

Examining early childhood outcomes, driven by Canadian data

Led by Birken, this publication is the second in a research series exploring maternal and paternal health and child nutrition and developmental outcomes using data collected from The Applied Research Group for Kids! (TARGet Kids!).

While the first publication focused on the link between maternal pre-pregnancy body mass index and infant growth, this study directly measured the preconception BMI of 209 fathers and zBMI of 218 children, with child measurements collected throughout early childhood, from birth until 10 years of age.

“Currently, few studies exist which examine the pre-pregnancy body mass index of fathers and how it may be connected to child growth, and those studies use only one measurement of child weight status and rely on self-reported data from parents,” says Arin Deveci, first author and Clinical Research Project Coordinator in the Translational Medicine program. “With data from TARGet Kids!, we were able to investigate the relationship between paternal BMI and longer-term child health outcomes, finding an association with zBMI and weight status in boys, but not girls.”

Informing real-world health interventions

The research team is using these findings to help to inform new interventions intended to promote healthy growth and development in children as part of the Healthy Life Trajectories Initiative (HeLTI Canada), a new ongoing clinical trial for women and their partners across Canada planning a pregnancy in the next few years.

“When planning a pregnancy, healthy weight in men, and their partners, may be important for the healthy growth of their children,” says Birken, who also co-leads HeLTI Canada. “The findings from this study will help support targeted health interventions for both men and women during the preconception period to promote healthy childhood growth.”

This study was funded by the Canadian Institutes of Health Research (CIHR).