Lower educational attainment has been associated with an increased risk of obesity; however, the causality of educational attainment in relation to adiposity, body composition, and fat distribution remains to be established. We used two-sample Mendelian randomization (MR) analyses of summary statistics with participants number ranged from 330,762 to 1,131,881 to test the causal effects of educational attainment in body fatness phenotypes [e.g., BMI, body fat mass, and waist-to-hip ratio (WHR)]. A total of 1,196 available single nucleotide polymorphisms associated with educational attainment were included in the current analysis. Eight complementary MR methods were used to test the robustness of our results. The genetically-instrumented higher educational attainment was consistently associated with a lower BMI [β -0.42, 95% confidence interval (CI) -0.45 to -0.39], body fat percentage (-0.31, -0.33 to -0.28), body fat mass (-0.36, -0.39 to -0.33), and waist circumference (-0.31, -0.33 to -0.28). The causal relationships of higher educational attainment with lower body weight, fat-free mass, and hip circumference were less consistent. There was no causal relation between educational attainment and WHR (Figure 1).

In conclusion, our findings indicate low educational attainment may causally increase BMI, body fat and waist circumference.

T. Zhou: None. D. Sun: None. X. Li: None. Y. Heianza: None. L. Qi: None.


National Heart, Lung, and Blood Institute (HL0791981, HL034594, HL126024); National Institute of Diabetes and Digestive and Kidney Diseases (DK115679, DK091718, DK100383, DK078616); Boston Obesity Nutrition Research Center (DK46300); United States-Israel Binational Science Foundation (20110360); American Heart Association (0730094N to L.Q.)

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