JMIR Publications

ABSTRACT

Background:

With health research practices shifting towards rapid recruitment of samples through the use of online approaches, little is known about the impact of these recruitment methods on continued participation in cohort studies.

Objective:

Report on the retention of a cohort of young women who were recruited using an open recruitment strategy.

Methods:

Women from the 1989-95 cohort of the Australian Longitudinal Study on Women’s Health, recruited in 2012-13 were followed up annually via online surveys in 2014, 2015 and 2016. Prevalence ratios for survey response were calculated using log-binomial model with generalised estimating equations with demographic, health-related and recruitment method characteristics examined as explanatory factors.

Results:

Of the 17,012 women who completed the baseline survey, approximately two-thirds completed the second survey, and just over half completed surveys 3 and 4, respectively. Women demonstrated transient patterns of responding with only 38% of women completing all four surveys. While retention of young women was associated with age, education, health status and health behaviours, method of recruitment was a key determinant of study participation in the multivariate model. Although women were more likely to be recruited into the cohort via social media (e.g. Facebook), retention over time was higher for women recruited through traditional media and referral approaches.

Conclusions:

A balance must be obtained between achieving representativeness, achieving rapid cohort recruitment and mitigating the pitfalls of attrition based on recruitment method in the new era of cohort studies, where traditional recruitment methods are no longer exclusively viable options.