Table 1.

Association of Obesity With Change in Intelligence Quotient and Neuropsychological Functioning, Dunedin Multidisciplinary Health and Development Study, 1972–2012

Measure	Mean Childhood and Adulthood IQ and Neuropsychological Test Scores by Body Composition in Standardized IQ Units
	Lean (n = 644)a			Obese (n = 269)b			Severely Obese (n = 170)c
	Child	Adult	Changed	Child	Adult	Changed	Child	Adult	Changed
IQ	101.25	101.28	0.04	97.01***	96.93***	−0.08	96.41***	96.18***	−0.23
Verbal IQ	100.94	101.05	0.11	97.74**	97.47**	−0.27	97.15**	96.82**	−0.33
Performance IQ	101.31	101.24	−0.08	96.85***	97.03***	0.19	96.35***	96.42***	0.07
Neurocognitive tests
Rey Delayed Recall	100.70	100.41	−0.29	98.38*	99.05	0.67	97.73*	98.13	0.40
Trails B	100.80	100.89	0.09	98.14*	97.94*	−0.21	96.53**	97.77*	1.24
Grooved Peg Board	101.68	101.40	−0.28	96.10***	96.76***	0.66	94.46***	94.96***	0.49

Abbreviation: IQ, intelligence quotient.

*P < 0.05; **P < 0.01; ***P < 0.001 versus the lean group.

^a Cohort members in the lean group did not have a body mass index (weight (kg)/height (m)²) in excess of the cutoff for obesity during the course of follow-up.

^b Cohort members in the obese group had a body mass index of 30 or higher at 1 or more assessments during follow-up.

^c Cohort members in the severely obese group had a body mass index of 30 or higher at 1 or more measurements during follow-up and were diagnosed with the metabolic syndrome or showed evidence of having elevated systemic inflammation (high-sensitivity C-reactive protein level >3 mg/L).

^d One point = 1/15 of 1 standard deviation.