Table 1.

Recruitment plan formulation

Planning considerations	Details
Target audience	Men aged 50–74 years who were overweight or obese and living in a capital city with a participating study centre. No further restrictions were placed as other eligibility criteria were to be assessed during the screening process
Call to action	Prospective participants were invited to visit study website or call a central information line to learn more about the study and complete the pre-screening questionnaire
Content of promotional material	Content decisions were guided by qualitative research in men’s health communication preferences [32], pro-bono advice from marketing professionals, and pre-testing and ongoing feedback from study participants Communication style: • Frank, humorous and empathetic message [32] • Simple, informal and easy-to-remember language Key components of the message: 1. Identification of the problem: men aged 50–74 years and overweight/obese are at risk of diabetes, weight gain and urinary and sexual problems 2. Positioning of the study as a solution: the Testosterone for the Prevention of Type 2 Diabetes (T4DM) study can support men to lose excess weight and address related health issues 3. Call to action: invitation to join the study and instructions on how to join
Promotional strategies/platforms	Promising promotional strategies were identified by review of the published literature, discussion with the study’s industry partners, brainstorming by the Steering Committee, suggestions from study participants and pro-bono advice from marketing professionals. Strategies were first tested for a short period of time, and if they appeared effective and affordable, were adopted on an ongoing basis.