Epidemiological studies--why don't people participate?

Maryn McKenna was awesome enough to take some time out of her vacation to blog about our recent ST398 paper, finding "livestock-associated" S. aureus in a daycare worker. She raised one question I didn't really address previously, regarding our participation by kids and workers at the facility (eight kids out of 168, and 24 out of 60 staff members).

(Staph screening is very non-invasive, by the way; it effectively involves twirling a long-handled Q-tip inside the front of your nostrils. Kinda makes you wonder why families would not have wanted to participate. On the other hand, since Iowa is the pig-growing capital of the U.S., they may have been motivated not to want to know.)

I thought I'd chat a bit about enrollment for this project, since getting people to participate is one of the most difficult parts of these types of studies. First, there really wasn't any mention of MRSA and swine for this particular study, so I doubt protecting the pig industry was high on anyone's list for reasons not to participate. However, anytime we do these type of studies, we're relying on the generosity of individuals in the community--particularly when we didn't really have participation incentives, as was the case in this project, which was done on a shoestring budget. (We passed out mini hand sanitizer bottles for adults, and had some little toys for the children).

We ran into several challenges for the research which limited our ability to enroll children. Along with a swab, we also had a questionnaire for parents and employees to fill out (as well as a third questionnaire for the director of the facility). For parents and employees, we asked about exposures: did they spend time in hospitals, around animals, at the gym? Had they recently had an infection? etc. For the directors, we asked about cleaning routines at the facility, as well as facility size (number of children and employees). So it wasn't only the swabs, but also a decent amount of paperwork to fill out when you include the informed consent forms. We also had to do all of this at the facility; because of the way we were sampling, parents didn't have a chance to take the questionnaire home to fill it out and then return it. So only parents (and employees) who had some spare time during either child drop-off or pick-up really had the chance to participate.

This particular study also started in roughly March 2009--right around the same time as the emergence of novel H1N1. There was a lot of news about the swabs that were taken to test for flu, which are more invasive than regular Staph swabs, so perhaps many potential participants had the mistaken assumption that the swab collection would be more uncomfortable than it really is. (When we were able to swab the child participants, most of them giggled and said that the swab tickled).

Finally, I should note that this facility was one of the larger ones we sampled, and to do this, my grad student returned several times during the day to try and catch parents during common drop-off/pick-up times (and employees who worked different shifts). However, even with this, we certainly missed a number of children and employees, such as those who were part-time and simply didn't attend or work the day that we were there. We did have higher participation rates at some of the other facilities.

So, I think timing and misinformation--rather than any kind of fear of finding out things they might not want to know--led to our lower participation rate at this facility.

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Which leads to the problem that whatever factors influence participation may somehow correlate with what you're trying to measure.

That's always a possibility, but in this study, I doubt it played much of a role. Those biases usually come into play more in (for example) case-control studies, where you're recruiting for various diseases and as such, people with those diseases have a bigger incentive to participate. Very few people know if they're colonized with Staph, and though people who have a history of Staph infection in themselves or their families may be more inclined to participate, we had very few (if any) of those in this study.

Get young/attractive people from the undergraduate program to, for credit if possible, mob the area and take participants individually, by hand if necessary, through the process. Undergraduate psych requires everyone to participate in a set number of studies so why can't the undergrad biology/epidemiology/premed programs require similar investments as study workers instead of as subjects. Evangelicals have long done this. Youthful enthusiasm and physical beauty can be harnessed.

Work through their bosses and pay office. If picking up their paycheck is set on the other end of a process of swabbing and paperwork your going to get more people being swabbed and questioned. Coercion works.

Health care and related fields are about helping, studying, manipulating people. If you want to study the flesh you have to press the flesh, and practice smiling, and play on peoples weaknesses.

Very well written explanation. I suppose that swabbing all the children and workers first, then requesting paperwork from those who test positive, was considered?

I am glad that Maryn McKenna had a link to your blog. Aetiology is now included in my information library.

Art--a bit, um, cynical view on things, in my opinion. Yes, I suppose that may increase participation, but no way will you ever find me combing through student ranks to find "attractive" people to help just for that purpose. I take my job to train students seriously, and the students who participate in these studies have an interest in epi/micro/infectious diseases.

Regarding participation being tied to picking up a paycheck--no way would our IRB ever, ever go for that. We have to justify in multiple areas in the application how we've worked to avoid just that kind of coercion. Rightly so, in my opinion.

Phil--thanks for the question. Either way we would have needed to get informed consent first, and that by itself isn't a very quick process. Plus, two things--one of the things we wanted to know was differences between those positive and negative for S. aureus, and doing it that way would not allow us to get to those differences; and second, there's a pretty high turnover rate of both kids and employees in many of these facilities, making follow-up with any kind of lag time difficult (not to mention, more labor-intensive).

Very interesting study. Too bad you were not able to catch the rest of the children during the in between times, as it would have been more accurate. Great post!

By Get Rid Of Hea… (not verified) on 10 May 2011 #permalink

You may not wish to screen for attractive people, but that doesn't mean you can't find some small means to make participation more attractive. I am aware that incentives can also skew the sample, but perhaps careful selection of that incentive could help. I don't know how much money is available, but if you are using a daycare, offering to pay for an hours care...or something similar might positively influence participation. Again, I know it is close to salesmanship and can skew results if used improperly, but even the slightest incentive could boost numbers.

By Mike Olson (not verified) on 13 May 2011 #permalink

We did offer incentives. Adults received mini hand sanitizer bottles, and the children were able to pick out a little toy. I also mentioned it was on a shoestring budget--some of those were even paid for out of pocket.

Cool, I kind of figured your budget was tight. I was thinking along similar lines: balloons, pencils, something with a logo on them. Shoot, I don't know if there is such a beast, but a t-shirt with a logo, "Iowa Citizens for Science," would be cool. I'm out in western Illinois near Davenport and I'd pay money for that dog. I just kind of like to promote science and math.

By Mike Olson (not verified) on 13 May 2011 #permalink

Yeah, the bottles of sanitizer had our Center for Emerging Infectious Diseases (CEID) logo on them. We unfortunately had to keep things to roughly $1-2 apiece for incentives for this one. For other studies led by colleagues, they did pass out CEID T-shirts, but even those were too pricey for our budget on this one.

However, if you're looking for swag, we do have some Iowa City Darwin Day shirts and misc. available.

Okay, I have to admit the t's are really cool. Frankly though, it always amazes me to find out that real science...big science is going on outside my back door. I'm reminded of Tyrone Hays and his research that freaked out big Ag. Years ago I was a Lab tech in the military and antibiotic resistant bacteria as well as those crossing the livestock human boundry are of special interest. I know you don't see yourself as such, but for me this communication is kind of like talking to a rock star.

By Mike Olson (not verified) on 13 May 2011 #permalink

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That reminds me that I need to sign up for the provincial long-term health study online.

By Markita Lynda:… (not verified) on 24 May 2011 #permalink

Cheap incentives for kids could include xeroxed pictures to color.

By Markita Lynda:… (not verified) on 24 May 2011 #permalink