The relationship among breakfast time, morningness–eveningness preference and body mass index in Type 2 diabetes

Abstract

© 2018 Diabetes UK Aims: Obesity is prevalent and related to poor outcomes in Type 2 diabetes. Evening preference and late meal times have been shown to be associated with obesity, but data are lacking in people with Type 2 diabetes. This study examined the relationship among meal timing, morningness–eveningness preference and BMI in Type 2 diabetes, using a mediation analysis. Methods: Some 210 non-shift workers with Type 2 diabetes participated in the study. Morningness–eveningness preference was assessed using a standard questionnaire, the Composite Scale of Morningness (CSM). Meal timing and daily calorie intake were obtained from 1-day food recall. A mediation analysis adjusting for relevant covariables was performed to explore whether morningness–eveningness had a direct effect on BMI, or whether the effect was mediated through the intermediate variable of meal timing. Results: Mean BMI was 28.4 ± 4.8 kg/m 2 . A higher BMI was associated with greater evening preference (P = 0.019), and non-significantly associated with late breakfast time (P = 0.053). BMI was not associated with other mealtimes or calorie intake. In addition, evening preference was associated with late breakfast time (P < 0.001). Mediation analysis revealed that breakfast time mediated the association between morningness–eveningness and BMI, i.e. morning preference (CSM ≥ 45) was associated with earlier breakfast time, and lower BMI by 0.37 kg/m 2 [coefficient = −0.365, 95% confidence intervals (CI): −0.877, −0.066), whereas the direct relationship between BMI and morningness–eveningness was non-significant. Conclusions: Late breakfast time mediated the relationship between morningness–eveningness preference and BMI. These results suggest that circadian preference and meal timing are novel and possibly modifiable risk factors for obesity in Type 2 diabetes.