Orpington, Kent-based Stralfors will produce and distribute invitations to a randomly selected group of mobile phone customers within the UK.
The study is being run by a research team at Imperial College London and the UK arm of the International Cohort Study on Mobile Phone Use and Health (COSMOS).
As well as sending out initial invitations and details of the study by post, Stralfors will send reminder communications in other formats, such as SMS.
The company will manage a total of 4.7m communications, starting this month, in a bid to sign up 100,000 UK participants.
Although the value of the contract has not been disclosed, Stralfors said it was a "big deal" for the company.
UK managing director John Carter said: "This is an important win for Stralfors and cements our position as a preferred partner and secure platform for critical mailing campaigns where a great deal hinges on the quality and timeliness of the communications."
Samantha Udondem, COSMOS project manager, added: "Our decision to choose Stralfors as our print and mail supplier was based on the company’s expertise as a multi-channel communications provider.
"Having carried out similar projects in the past, we were confident Stralfors understood the specific needs of our project and would be able to deliver outputs to the quality and within the timeframe required."
