Introduction To examine whether the accumulation of obesity-related eating behaviours such as eating quickly, eating until full, eating right before bedtime and breakfast skipping are associated with incidence of type 2 diabetes mellitus (T2DM) among middle-aged Japanese men and women.

Methods The 2840 subjects (890 men and 1950 women) who were aged 40–69 year and free of T2DM were enrolled at baseline survey from 2003 to 2006 in a community-based longitudinal study, the CIRCS. The subjects were asked following four eating behaviours by questionnaire at baseline: “speed of eating”, “eating until full”, “eating right before bedtime” and “breakfast skipping”. T2DM was defined as fasting serum glucose ≥7.0 mmol/l, non-fasting serum glucose ≥11.1 mmol/l or medication for T2DM. We followed up to March 2010, and calculated HR and 95% coefficient interval (95% CI) of T2DM by using Cox proportional hazard model after adjustment for potential risk factors.

Results During 7-year follow-up period, 155 cases (70 men and 85 women) had an onset of T2DM. We calculated multivariate HR (95% CI) of T2DM for each number of eating behaviours among both men and women. Compared with persons without any eating behaviours, the multivariable HR (95% CI) of persons with 1, 2 and ≥3 of eating behaviours were 2.35 (1.06 to 5.19), 1.54 (0.65 to 3.63) and 3.24 (1.29 to 8.13), p for trend=0.09 in men and 0.92 (0.52 to 1.62), 0.67 (0.35 to 1.30) and 1.97 (0.92 to 4.22), p for trend=0.67 in women.

Conclusion Our finding suggests that the accumulation of obesity-related eating behaviours raise the risk of T2DM for middle-aged Japanese men.