Sunday, September 22, 2013

Impaired IQ and academic skills in adults who experienced moderate to severe infantile malnutrition: A 40-year study

After a fair bit of looking I cannot find a good explanation of WHY some Barbadian infants were malnourished.  It seems likely that they came from poorer or less functional families -- so  poverty alone would explain the effects observed. Poor people are dumber on average. Contrary to the conclusions below, the effects may be entirely genetic  -- JR

By Waber DP, Bryce CP, Girard JM, Zichlin M, Fitzmaurice GM, Galler JR.


Objectives: To evaluate IQ and academic skills in adults who experienced an episode of moderate-to-severe infantile malnutrition and a healthy control group, all followed since childhood in the Barbados Nutrition Study.

Methods: IQ and academic skills were assessed in 77 previously malnourished adults (mean age = 38.4 years; 53% male) and 59 controls (mean age = 38.1 years; 54% male). Group comparisons were carried out by multiple regression and logistic regression, adjusted for childhood socioeconomic factors.

Results: The previously malnourished group showed substantial deficits on all outcomes relative to healthy controls (P < 0.0001). IQ scores in the intellectual disability range (< 70) were nine times more prevalent in the previously malnourished group (odds ratio = 9.18; 95% confidence interval = 3.50–24.13). Group differences in IQ of approximately one standard deviation were stable from adolescence through mid-life.

Discussion: Moderate-to-severe malnutrition during infancy is associated with a significantly elevated incidence of impaired IQ in adulthood, even when physical growth is completely rehabilitated. An episode of malnutrition during the first year of life carries risk for significant lifelong functional morbidity.


Older fathers don't have dumber kids

Some recent research below bears on the often asserted "danger" of older fathers

The effect of paternal age on offspring intelligence and personality when controlling for paternal trait level

Ruben C. Arslan et al


Paternal age at conception has been found to predict the number of new genetic mutations. We examined the effect of father’s age at birth on offspring intelligence, head circumference and personality traits. Using the Minnesota Twin Family Study sample we tested paternal age effects while controlling for parents’ trait levels measured with the same precision as offspring’s. From evolutionary genetic considerations we predicted a negative effect of paternal age on offspring intelligence, but not on other traits. Controlling for parental IQ had the effect of turning a positive-zero order association negative. We found paternal age effects on offspring IQ and MPQ Absorption, but they were not robustly significant, nor replicable with additional covariates. No other noteworthy effects were found. Parents’ intelligence and personality correlated with their ages at twin birth, which may have obscured a small negative effect of advanced paternal age (< 1% of variance explained) on intelligence. We discuss future avenues for studies of paternal age effects and suggest that stronger research designs are needed to rule out confounding factors involving birth order and the Flynn effect.


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