NEO personality domains and gender predict levels and trends in body mass index over 14 years during midlife

Mixed models were used to examine NEO-PI scores as predictors of body mass index (BMI) over a 14 year period during midlife. Average BMI levels during midlife were positively related to Neuroticism and negatively related to Openness, Agreeableness, and Conscientiousness. Relations for three domains were modified by gender. Neuroticism was significantly related to BMI in females only. Extraversion was positively related to BMI in males, whereas, this relation was non-significant in females. The relation between Conscientiousness and BMI was significant in males and females, however, the magnitude of the negative association was stronger in females. Conscientiousness also predicted change in BMI during midlife such that participants who were lower in Conscientiousness tended to show larger gains in BMI with age.