The use of the world wide web in epidemiological research

The world is becoming smaller. Through technical innovations all kind of communication is simplified, people come closer, and borders are erased. The Internet plays a major part in this process not only through the simplification of everyday life - but also of scientific life. Increasingly laypersons access the immense information available on the Internet in search for health information. The scientific society, on the other hand, lags behind. It has yet to make use of the possibilities inherent in these technologies to their full extent. As populations become more dynamic and geographically dispersed, this becomes a necessity in order to collect information fundamental in epidemiological studies. As the outside world becomes smaller, the world of the Internet and its possibilities becomes larger. This thesis and the studies therein fall within the filed of e-epidemiology. This recently defined scientific field includes the acquisition, maintenance, and application of epidemiological knowledge and information using digital media such as the Internet, mobile phones, digital paper, and digital TV. In particular, we studied the dissemination of cancer risk sites and the collection of health information - both mediated via the Internet. Despite the immense amount of health information available on the Internet, there are no guarantees as to the quality of the information accessible. In study I we performed a systematic search of the Internet and studied the quality of the found cancer risk sites. The results were discouraging, with few websites fulfilling the demands of the quality criteria recommended by the EU and with no improvements noted in the consecutive searches. In study II-IV we used the Internet to collect health information from Swedish women in two large population-based studies of 50 000 and 25 000 women respectively, aged 18-60. We demonstrated the feasibility of using the Internet for data collection in large epidemiological studies. Level of education and income differed somewhat between the responders to the web and paper. Despite these differences, the bias from the association in the target population was similar for both response methods. As the absence of bias is important for the survival of the method, this was a very important find. Another advantage when using the web-mode is the possibility to study the lurkers (participants that enter, start responding to, but do not complete a web-questionnaire). As lurkers are potential responders, they present an important goal for research aiming at preventing drop out and increasing response rates. As such the results are another important argument for the endurance of the method. Although the world is getting smaller in the sense of simplified communication, the opposite holds true for the epidemiological society. The dynamic, mobile features of current populations complicate data collection for large population-based studies. The Internet holds advantageous properties with the capacity to overcome these problems. The Internet access keeps increasing in all parts of the world and all parts of society. It is important that the scientific society realizes the need to distribute qualitative information so as to maintain the trust and faith of a growing number of Internet users. Concurrently the Internet is facilitating the globalization, thus complicating the collection of information from an increasingly mobile population. The scientific society needs to make use of this innovative tool with its possibility to erase borders and time zones, and capability to efficiently collect health information in epidemiological studies. The world is becoming smalle