24 For this reason, it is essential Tofacitinib for clinical research to investigate if nonresponse is accidental and, if not, whether it is systematically associated with particular characteristics to a relevant degree. Conclusive data are lacking, and methodologists have focused almost exclusively on common demographic parameters: younger age7,19 and male gender4,19 predicted later responses. Other studies performed in different parts of the world found that younger age,6,13 male gender,6,13 being single or divorced,6,8,21 and a lower educational level5,6,13 were associated with reduced participation. In some studies, however, younger age25 and male gender26 were related with higher response rates. Predictors of nonresponse are often associated with the study topic22,23: in a study of alcohol consumption, interestingly, abstainers were less likely to respond than moderate drinkers.
22 Researchers also investigated nonresponse at the item level27: amongst participants who returned questionnaires, they examined whether participants were more likely to skip some items rather than others. The patterns revealed were similar to those for nonresponse at the questionnaire level.27 However, most demographic differences between respondents, nonrespondents, and late respondents were small.4,6,13,19,22,27 Our results confirmed those earlier findings. Apart from smoking, which decreased the odds of returning the follow-up questionnaires by 1.5 times (95% CI, 1.1�C2.0), the effects we found among our control variables were not relevant. Individuals needed to be 14.
4 years (= 1 SD) older in order to return the baseline questionnaires 1 week earlier (P = 0.048). Men, on average, returned questionnaires 3 weeks later than did women (P = 0.009). These values are insufficient to bias estimates. If a systematic difference GSK-3 between respondents and nonrespondents to follow-up does indeed exist, other characteristics must be responsible for it. Patients were asked in an open-ended question about their motives for participating in cardiovascular trials.28 The top answers were personal health benefits (82.2%), interest in research (44.1%), and the possibility of benefiting society (29.1%). Although everybody might be interested in benefiting themselves and society, not everyone would agree regarding the usefulness of studies. But what explains the difference? As it is not explained by educational attainment��only small5,6 or no21 differences have been found��a reasonable approach is to examine if personality plays a role. However, only a few studies have considered this possibility. A family study found that siblings of nonrespondents scored higher on scales of anxious depression and neuroticism; however, the siblings themselves were actually respondents.