IQ, Waist-Hip-Ratio Linked
Among 40 year old men who participated in the survey, 5,380 persons had taken an IQ test during the mandatory Swedish conscription examination at a mean (sd) age of 18.1 (1.0) years, 21.0 (1.0) years before the survey. The results of the IQ test were standardized to a normal distribution score with nine levels. Waist-Hip-Ratio (WHR) was calculated as waist circumference divided by hip circumference. Results: WHR among middle-aged men differed significantly between IQ levels (p<0.001). The association was inverse, with the highest mean (sd) WHR value 0.91 (0.06) for the men with lowest IQ and the lowest value 0.88 (0.06) for the men with highest IQ (see figure). The results were robust when adjusting for confounding factors in a linear regression model. Conclusions: Waist-hip-ratio, a well known risk factor for cardiovascular disease, was among men inversely correlated with intelligence in late adolescence.