In the past, studies have established that lower cognitive performance in childhood or adolescence may be associated with a higher rate of obesity in late adulthood. But a new study returns to these conclusions which would be potentially erroneous.
- Previous studies have suggested that lower cognitive ability in childhood or adolescence may be associated with higher BMI or obesity rates in late adulthood.
- To verify this, researchers used data on 12,250 siblings.
- Their results call into question the previous conclusions.
The links between cognitive ability and body mass index (BMI) established by several previous studies may actually be due to confusion with other family history factors, according to a new study published April 13 in the journal available online PLOS Medicine.
Poorer cognitive abilities are not necessarily linked to obesity
These earlier studies had concluded that lower cognitive ability in childhood or adolescence may be associated with higher BMI or obesity rates in late adulthood. To verify this, the researchers behind this new study, Liam Wright, a researcher at University College London, as well as Neil M. Davies and David Bann, used data on 12,250 siblings from 5,602 monitored households. from adolescence to age 62 in four separate cohort studies of young Americans.
In comparing the links between cognitive ability and BMI within families, the team took into account previously unobserved factors related to family history. The researchers found that moving from the 25th to the 75th percentile of adolescent cognitive ability was associated with an estimated 0.61 kg/m2 decrease in BMI (95% CI -0.90 to -0.33 ) after adjusting for family socioeconomic status.
However, when they compared siblings, they found that moving from the 25th to the 75th percentile of adolescent cognitive abilities was associated with a decrease in BMI of just 0.06 kg/m2. (95% CI -0.35 to 0.23).
Data on siblings are useful for studying research bias
“The results suggest that existing findings on the link between cognitive ability and BMI are biased by shared family factors. (…) Data on siblings may also be useful in assessing potential biases for these health outcomes”explain the authors in a communicated.
“Does greater cognitive ability (intelligence) help prevent too much weight gain? Many studies have found an association between the two, but our study suggests that these links may not be causal in nature”adds Liam Wright.
