Distress experienced by mothers and fathers in the first few years of a child's life, particularly during infancy, is linked with accelerated weight and excess fat gain from age 5 to 14 years, according to new research being presented at the European Congress on Obesity (ECO) held online this year.
The findings also suggest that girls are sensitive to both mothers' and father's self-reported distress during infancy; whereas boys seem influenced only by their fathers' distress reported at 9-months.
"We know the first few years of life are crucial for healthy weight development, however we don't know exactly which psychological and social exposures during the early years put some children at greater risk of developing overweight in later childhood", says Kristiane Tommerup from University College London, UK, who led the research. "Our findings underscore how a lack of social, mental health, and socioeconomic support available to parents may have long-term health implications for their children."
Today, more than a third of UK children are expected to have a body mass index (BMI) in the overweight or obese range by the time they are 10 years old. Moreover, children living in deprived areas of the UK are twice as likely to have developed obesity than those living in more affluent areas by the age of 5 years. This suggests that early social and home environments are crucial for healthy weight development.
In the UK, almost a third of children are living in a household with at least one parent reporting substantial emotional distress, such as depression or anxiety. Previous studies suggest that mothers' distress in early childhood is linked to a greater risk of overweight and obesity in their children. But despite one in eight UK children having a father who reports significant emotional distress, whether a fathers' distress is associated with children's long-term obesity risk isn't known.
To find out, researchers from University College London used data from the UK Millennium Cohort Study, a long-term study of 19,000 families and children born between 2000 and 2002. They analysed data on over 6,000 children  to investigate associations between distress self-reported by mothers and fathers in early childhood (at 9-months and 3-years of age), and how children's weight (body mass index; BMI) and excess body fat (Fat Mass Index; FMI) changed from age 5 to 14 years. The trajectories represent the speed of increase in BMI and fat gain across childhood.
The results were adjusted for a range of potentially confounding factors including: family income and structure; maternal and paternal employment, education level, and BMI; child's gestational age, birth weight, and breastfeeding duration.
In all, around 10% of mothers and 6% of fathers reported emotional distress when their child was aged 9 months. However, by age 3 years, mothers and fathers reported more similar levels of distress (both around 10%).
The analysis found that fathers' distress reported in infancy, but not during toddlerhood, was associated with steeper increases in BMI and excess body fat for both girls and boys. However, mothers' distress reported in both infancy and toddlerhood was associated with steeper increases in BMI and excess body fat in only girls.
"It seems that distress experienced by fathers during infancy may place their children at greater risk for developing overweight across their childhood", says Tommerup.
"This underscores the key role that fathers play in shaping the healthy growth of their children from the start of life. In order to protect children's health, more needs to be done to support mental health and wellbeing among both parents in the early years, as well as tackle the wider social drivers of mental health inequalities. Further studies are needed to uncover the biological, social, and behavioural mechanisms underlying these associations."
The authors acknowledge that the findings are associations only, so can't establish causation, and point to several limitations, including that this study only included two-parent households, and the participants were mainly from White ethnic backgrounds, which may limit the generalisability of the results to other groups.