SMS versus telephone interviews for epidemiological data collection: feasibility study estimating influenza vaccination coverage in the Swedish population.

This study compared the use of Short Message Service (SMS) on mobile phones and the use of telephone interviews in collecting self-reported data about influenza vaccination. Through random selection from the Swedish population registry, 2,400 individuals were assigned to be contacted through SMS (SMS-group), and 2,150 were assigned to undergo personal telephone interviews (TI-group). Both groups were asked three questions about influenza and influenza vaccination. Mobile phone numbers were found for 1,055 persons in the SMS-group of whom 154 (6% of the original sample; 15% of all who had a listed mobile phone number) responded. Landline or mobile phone numbers were found for 1,636 persons in the TI-group and 1,009 (47% of the original TI sample; 62% of those where a telephone number was found) responded. The vaccination data collected via SMS was not statistically significantly different from data collected through telephone interviews, and adjustment for different background factors did not change this. Compared to the original sample, there was an under representation of elderly and less educated individuals among the participants in the SMS-group, and under representation of less educated in the TI-group. Though the participation rate was low, SMS is a feasible method for collection of information on vaccination status data among the Swedish population compared to telephone interviews.

Evaluation of an internet-based hearing test--comparison with established methods for detection of hearing loss.

BACKGROUND: Hearing impairment is most accurately measured by a clinical pure-tone audiogram. This method is not suitable for large-scale, population-based epidemiological studies as it requires that study participants visit a clinic with trained personnel. An alternative approach to measuring hearing ability is self-estimation through questionnaires, but the correlation to clinical audiometric tests varies. OBJECTIVE: To evaluate an Internet-based hearing test pilot compared to a question about self-estimated hearing and the feasibility of using an Internet-based hearing test and an Internet-based questionnaire in a population of 560 members of the Swedish Hunters' Association in the age group 20-60 years. METHODS: An invitation was mailed to the participants in March 2007 together with the URL to the study Web site, a personal username, and a password. The Web site included the questionnaire, the hearing test, and instructions for participating in the study. The hearing test resembles a clinical audiogram presenting 6 tones between 500 and 8000 Hz. Tones are presented between 0 and 60 dB, and the participant responds to the tones by pressing the space bar. The hearing test requires headphones and is based on JAVA programming. Before the participant can start the hearing test, it has to be calibrated against a reference person with good hearing between 15 and 35 years of age. RESULTS: After 5 months, 162 out of 560 (29%) had answered the questionnaire, out of which 88 (16%) had completed the hearing test. Those who actively declined participation numbered 230 out of 560 (41%). After removing duplicates and hearing tests calibrated by unreliable reference data, 61 hearing tests remained for analysis. The prevalence of hearing impairment from the Internet-based hearing test was 20% (12 out of 61), compared to 52% (32 out of 61) from the self-estimated question. Those who completed the hearing test were older than the non-participants, and more had headphones (P = .003) and the correct version of the JAVA program (P = .007) than those who only answered the questionnaire. CONCLUSIONS: Though an Internet-based hearing test cannot replace a clinical pure-tone audiogram conducted by a trained audiologist, it is a valid and useful screening tool for hearing ability in a large population carried out at a low cost.

New times, new needs; e-epidemiology.

The successful and systematic collection of demographic and lifestyle data is central in the process of any epidemiological study. The traditionally used methods such as face-to-face and telephone interviews as well as paper-questionnaires are increasingly failing to produce good qualitative results within financially feasible limits. Tools that are better suited for the present dynamic populations are needed and the Internet presents a powerful alternative for the collection of data with several intrinsic features still unexplored.

Optimizing the design of web-based questionnaires--experience from a population-based study among 50,000 women.

BACKGROUND: Web-questionnaires are an important tool for future epidemiological research because these allow for rapid and cost-efficient assembly of self-reported information on risk factors and health outcomes. However, to achieve high response rates it is essential to accommodate factors that prevent drop out and so insure validity of future studies. We aim to study how socio-demographic variables as well as design issues such as the ordering and level of difficulty (Easy-to-hard vs. Hard-to-easy) of questions in a web-questionnaire affects the probability of drop out and non-response. METHOD: In 2003 we invited 47,859 women participating in an ongoing prospective study to a follow-up using a web-based mode. Two versions of the questionnaire existed, varying in level of difficulty (Easy-to-hard vs. Hard-to-easy). We report drop out (proportion non-completers) between groups defined by level of difficulty and estimated adjusted risk differences. RESULTS: The drop out differs significantly depending on the order of the questions in the web-questionnaire. The socio-demographic pattern among lurkers (participants that enter, start responding to, but do not complete a web-questionnaire) differs from that among completers of web-questionnaires. CONCLUSIONS: An additional 6% units of completers--persons initiating and completing the questionnaire--can be obtained by considering the ordering of questions. A group uniquely identified in web-surveys, as lurkers are potentially easier to persuade to complete an already started web-questionnaire compared to a non-responder. Lurkers thus constitute a unique opportunity of decreasing the drop out rate and therefore merit future research.

Feasibility of using web-based questionnaires in large population-based epidemiological studies.

To date, few large web-based epidemiological studies have been performed in a population-based setting. Sweden has optimal prerequisites for web-based studies with more than 80% of the general population having access to the Internet. Our aim was to investigate (I) response rates in an epidemiological study using primarily the web as a tool for data collection and (II) whether socio-demographic patterns vary between responders to a web and a paper questionnaire. In 2003, we invited 47,859 women to complete a web questionnaire. Two reminders were sent to non-responders; in the first a random sample received a paper questionnaire and in the second the majority received a paper questionnaire. All other non-responders received web questionnaires. Differences in response rates between responders to web and paper questionnaires with regard to socio-demographic and other variables were analyzed, and estimates of the bias introduced by these differences were estimated. In total, 41% of the women responded to the web questionnaire and 31% to the paper questionnaire (overall response rate 72%). The web-, paper- and non-responders respectively did not differ significantly in age, physical activity levels, and body mass index. Women answering web or paper questionnaires had a higher level of education and income and a lower level of smoking than non-responders. The bias associated with collecting information using web questionnaires was not greater than that caused by paper questionnaires. We conclude that web-based questionnaires are a feasible tool for data collection in large population based epidemiological studies in Sweden.

Can we trust cancer information on the Internet?--A comparison of interactive cancer risk sites.

OBJECTIVE: To investigate the prevalence and quality of interactive cancer risk sites on the Internet. METHODS: A cancer risk site was defined as a website that gave an estimate of the individual risk of developing cancer. Six search engines and one Meta crawler were used to search the Internet for cancer risk sites (including breast, prostate, colon, and lung cancer). A set of defined quality criteria for health related websites was used to evaluate the websites during 2001 and 2002. RESULTS: The number of cancer risk sites, as defined above, increased by 50% between 2001 and 2002. Only two out of 22 cancer risk sites fulfilled the quality criteria adequately. No signs of a change in trend (with regard to the quality criteria met) were noted in January 2005. CONCLUSIONS: The overall quality of the documentation on the cancer risk sites was poor and no improvement was seen during the study period. The majority of the cancer risk sites do not give reliable risk estimates.