During the period 1992 to 1994, the female population aged 40 to 69 ye
ars old and living in Cent, Belgium, was invited through a personal le
tter to participate in a breast cancer screening programme. The women
were asked to consult a physician before referral to a local radiologi
st. After six months, a reminder letter was sent. The eligible populat
ion amounted to 40,713 women. Of these, 22.5% were recorded to have at
tended for a screening mammography. The uptake levels were analysed pe
r statistical sector, which is a more or less homogeneous quarter in s
ocial respect. The age-standardized participation ranged from 6 to 42%
among the 150 sectors taken into account. The participation was defin
itely highest in well-to-do neighbourhoods and lowest in the poorer in
ner-city quarters. In a multivariate analysis, social exclusion indica
tors such as percentage of persons on welfare and percentage of unoccu
pied dwellings ranked first. On condition that this social gradient is
confirmed on an individual basis, sociogeographical analysis may well
be a powerful tool in area-based health promotion campaigns.