Objectives: To examine differentials and time trends in self-reported Pap test rates by socio-economic status (SES) from the 1989/90 and 1995 Australian National Health Surveys (NHS).
Methods: The unit record data for females were extracted from the two NHSs and combined. The outcome variable of interest was 'having a Pap test in the past three years'. The principal study factor was SES measured as individual characteristics and SES of area of residence. Migrant status, rurality, year of survey and age were controlled for in logistic regression models.
Results: Self-reported rates of having a Pap test in the past three years were higher in women from higher compared with lower SES groups. Compared with women with a bachelor or higher degree, the odds of reporting having a Pap test in the past three years in women with no post-school qualification was 0.86 (p<0.0005). Women with a gross annual income of less than $20,000 had significantly lower odds (OR=0.79) compared with women earning $40,000 or more. Blue collar (OR=0.84) and not employed (OR=0.73) women also had significantly lower odds compared to the referent white collar group.
Conclusion: This study reveals differentials in Pap screening behaviour by individual measures of SES in Australia. Area-based SES measures under-estimated the SES differentials in Pap test rates compared with individual measures. Derived population attributable fractions reveal that about a quarter of self-reported under-screening is accounted for by low SES when measured individually, compared to 8% when SES is measured ecologically.