ObjectivesPre-diabetes is an important indicator of future diabetes burden and many countries are reporting prevalence estimates of pre-diabetes. To date in Ireland, estimates of the prevalence of pre-diabetes were unavailable. Our objectives were to estimate the prevalence of pre-diabetes in a nationally representative sample of Irish adults and to explore determinants of pre-diabetes. MethodsThe Survey of Lifestyle Attitudes and Nutrition 2007 was a cross-sectional survey on health and lifestyle in a nationally representative sample of Irish adults. Analysis was performed on a subsample of 1132 participants 45years who provided blood samples. Determination of pre-diabetes was based on American Diabetes Association HbA(1c) cut points of 39-46mmol/mol (5.7-6.4%). To explore determinants, we modelled pre-diabetes prevalence as a function of a set of health system and socio-demographic variables using logistic regression. ResultsThe overall weighted prevalence estimate of pre-diabetes in participants 45years was 19.8% (95%CI 16.4-23.9). There was no significant difference between age or gender-specific prevalence rates. Obesity was significantly associated with pre-diabetes on univariate and multivariate analysis. Population attributable fraction estimates for excess BMI, physical inactivity and poor diet as causes of pre-diabetes were 31.3% (95%CI -3.9 to 54.5), 10.0% (95%CI -2.7 to 21.3) and 6.1% (95%CI -4.9 to 15.9), respectively. ConclusionsThe high levels of pre-diabetes detected in this study are worrying. Population level interventions to address diet and lifestyle factors are needed urgently to prevent progression to diabetes in high-risk individuals.