THE INFORMATION AVAILABLE FROM SWEDISH DATA SYSTEMS RELEVANT TO EVALUATION OF A CANCER PREVENTION PROGRAM IN STOCKHOLM COUNTY

Relative changes in disease incidence for different population groups can shed light on two questions: if they can be linked to groups expos ed to contrasting types or intensities of intervention in a disease pr evention program, they provide a way to assess the program's effective ness; if they can be linked to groups with different levels of risk fa ctors, they can provide information on the etiological relationships u pon which prevention programs can be based. Sweden's registers and dat abases are reviewed as potential sources of cancer incidence data. In principle, these data may be used to evaluate the Stockholm Cancer Pre vention Programme if ''place of residence'' is a sufficiently valid in dicator of exposure to intervention. Through record linkage, the effec t of socioeconomic status can be examined and controlled for. For etio logical studies, differential changes in cancer incidence between geog raphical areas can be linked to, for example, local changes in diet, a lthough data on this may be limited. However, given the ''prospective' ' design and the expected lag between habit change and effect on morbi dity, the sizes of the groups and the length of the period studied wil l have to be very substantial.