Three year old children who spend more than eight hours watching television per week are at an increased risk of obesity, finds a study published online by the BMJ this week.
This is just one of eight aspects of early life found to be linked to obesity in UK children, and these results support the theory that the early life environment can determine later risk of obesity.
The study involved 8,234 children aged 7 years and a further sample of 909 children who were taking part in a large UK study of parents and children. Height and weight were measured and body mass index (BMI) was calculated.
In the entire group, four factors were independently associated with a risk of obesity at age 7:
- Increasing birth weight
- Parental obesity (one or both parents)
- More than eight hours spent watching television per week at age 3 years
- Short sleep duration (less than 10.5 hours per night at age 3 years
A further four factors were significant for the children in the additional sample:
- Size in early life
- Rapid weight gain in the first year
- Rapid catch-up growth between birth and two years
- Early development of body fatness in the pre-school years, before the age at which body fat should be increasing (at age 5/6 years)
The precise mechanisms by which these variables might increase the risk of obesity are complex, say the authors. For instance, parental obesity may increase the risk of obesity through genetics, or by shared family characteristics in the environment such as food preferences.