Weaknesses in this study include the modest size of the cohorts, borderline significance of some SNPs in the absence of correction, cross-sectional design and recruitment limited to Caucasians with a minimum 15 pack years.
Nonetheless, local factors and individual leaders may have a strong impact on recruitment, limiting the generalizability of the experience of these studies.
A randomised comparison of opt-out with opt-in study recruitment found greater non-participation and non-response bias with the latter [ 22], suggesting our own method of recruitment limited further bias.
The low response rate, as well as the possible selection bias related to recruitment, limited the generalizability of the results since we cannot be certain that the respondents were not systematically different from those not invited and non-responding.
A trial with broader recruitment, limited to only those with A1C >7.0%, and allowing randomized control subjects to participate in the program after a 6-month trial would prove more definitive.
The geographic boundary, chosen to facilitate recruitment and limit transportation burden and costs, included a wide variety of neighborhoods in Boston and surrounds ranging from ethnically and socioeconomically diverse urban communities to suburban regions with predominately white, middle-class residents.
Furthermore, activated macrophages block preadipocyte recruitment and limit hyperplasic expansion of the adipose tissue.
The area of eligibility, which covers 6-km radius around the rehabilitation center at Keio University Hospital, was selected to facilitate door-to-door recruitment and limit transportation burden and cost.
During the study period 1643 patients were admitted to the ICU and 831 did not meet inclusion criteria: 791 had an expected length of stay in the ICU of less than 48 hours and 40 exceeded the recruitment time limit.
Despite the fact that recruitment was limited to English language speakers, most researchers felt that they recruited a good spread of the local population, although this did depend on the clinical area under investigation and the time commitment involved.
