To assess patterns in adult smoking rates in Ireland across two main socio-economic indicators: level of education and social class (SC), using national cross-sectional survey data from 1998 and 2007.

Complete smoking-related information on adults (≥18 years) for 1998 [n=6,293] and 2007 [n=10,251] were analysed. Age-standardized smoking rates for each of the two main indicators were computed overall and by sex using 2002 Census as the standard population. 

Relative index of inequality (RII) in age-standardized smoking rates was computed (comparing the lowest with the highest socio-economic groups) for each calendar year based on relative ranking (0=highest; 1=lowest) and then regressing the cumulative percentile distribution of the sub-classes within each year. 95% confidence intervals (CI) for RII were generated.