Sleep disturbances, body mass index and eating behaviour in undergraduate students

This study investigates the association between sleep disturbances, body mass index (BMI) and eating behaviour in a sample of undergraduate students. The sample comprises 870 medicine and dentistry students from Coimbra University (62.5% females), aged between 17 and 25 years. The Eating Attitudes Test-40 was used to measure eating behaviour, and two questions were applied addressing difficulties of initiating sleep (DIS) and difficulties of maintaining sleep (DMS). A sleep disturbance index (SDI) was calculated from the sum of DIS and DMS scores. Body mass index (BMI) was determined from self-reported weight and height. The correlation analyses generally indicated that global eating disturbance, bulimic behaviour dimension and social pressure to eat were associated particularly with sleep difficulties. An association between diet concerns and sleep difficulties was less consistent. Regression analyses showed that bulimic behaviour (BB) and social pressure to eat (SPE) dimensions were associated significantly with sleep difficulties (DIS, DMS, SDI) in the total sample (BB: from P<0.01 to P<0.001; SPE: P<0.05) and in males (BB: from P<0.05 to P<0.001; SPE: P<0.05) and with insomnia symptoms (P<0.01). In females, bulimic behaviour was the only factor associated significantly with sleep difficulties (SDI, DIS; P<0.01) and with insomnia symptoms (P<0.05). Although BMI was correlated negatively with sleep difficulties (P<0.05), regression analyses indicated that it was not associated significantly with them. Our findings support an association between eating behaviour and sleep disturbances in both genders, which may have treatment implications.