Preventing obesity from early childhood
What role do factors in early life play in determining growth and obesity in later life?
Dr Miaobing (Jazzmin) Zheng, an NHMRC Early Career Fellowship researcher at IPAN, is investigating what determines growth trajectories and obesity in early childhood.
Given the high prevalence of childhood obesity, there is a pressing need to address obesity prevention early in life. In Australia, 25 per cent of children are overweight or obese. This figure rises to 67 per cent in adults. With these numbers come significant health implications, such as heart disease and type 2 diabetes.
“We know rapid growth during infancy is a potent risk factor for obesity, with infants experiencing rapid growth 3.7 times more likely to be obese in later life,” Dr Zheng explained.
“Early behavioural factors including dietary intake, sedentary behaviour, physical activity, and sleep determine growth and subsequent obesity risk.”
Dr Zheng has led a series of studies looking at the effects of infant feeding, early dietary and behavioural factors on growth patterns and later obesity.
“A better understanding of the developmental trajectories of growth in early life and its determinants will help guide obesity prevention strategies,” she said.
Maternal and postnatal factors
Using the results of two INFANT studies of more than 900 children, Dr Zheng analysed mothers’ country of birth, pre-pregnancy BMI (Body Mass Index), and education; and child’s postnatal rapid growth, sex and gestational age.
Children who experienced postnatal rapid growth, and whose mothers were Australian born and overweight/obese pre-pregnancy showed less favourable growth trajectories in early childhood.
This study examined infants who were breastfed up to 6 months, with solids introduced from 6 months as part of the INFANT data.
Infants who were breastfeed longer than 6 months were associated with more favourable growth patterns in early childhood (birth to 5 years). Breastfeeding duration had a more profound effect on BMI growth than timing of solids introduction.
Early dietary/behavioural factors
Again using INFANT data, Dr Zheng examined lifestyle patterns at 18, 42 and 60 months, specifically:
- discretionary food and screen time
- fruit and vegetable consumption and outdoor time.
She found that children showed stable trajectories of lifestyle pattern (healthy, unhealthy) and BMI (Low, Mid, High) from ages 18 to 60 months.
Three trajectory groups were identified:
- Unhealthy lifestyle pattern, Low BMI (30%)
- Healthy lifestyle pattern, Mid BMI (53%), and
- Unhealthy lifestyle High BMI (17%).
She found that the child’s birth weight, maternal pre-pregnancy BMI, mothers’ dietary patterns, and mothers’ TV-viewing time significantly contributed to the child’s lifestyle pattern trajectory.
“We’ve been able to show that lifestyle patterns start early and track well into early childhood, highlighting the importance of lifestyle obesity prevention early in life,” Dr Zheng said.
“This work will provide the foundation for future multi-behaviour approaches that target healthy diet, physical activity and sedentary behaviours.”
In this study, Dr Zheng wanted to explore how sleep duration trajectories (total, night-time and daytime) link with BMI trajectories in early childhood.
She found that longer night-time sleep duration was associated with lower BMI trajectories in early childhood. This was not the case for total or daytime sleep duration.
“These results underscore the importance of adequate night-time sleep for healthy body-weight development in early childhood,” Dr Zheng said.
Dr Zheng is continuing to explore these research questions in different population groups and investigate the underlying mechanisms.
“We are building critical scientific evidence for nutrition strategies and policies that achieve optimal child growth and early obesity prevention,” she said.