An individually based lifestyle intervention for workers at risk for cardiovascular disease: a process evaluation

Evaluate counselors' adherence to an intervention protocol, counselors' competence, and the associations between three process indicators and body weight at follow-up in a 6-month individually based lifestyle intervention for construction workers.

Process evaluation with qualitative and quantitative data.

Occupational health service.

A total of 408 male construction workers with an elevated risk of cardiovascular disease received the intervention, and 27 occupational health professionals delivered the intervention.

Seven counseling sessions, the first during which four prescribed items had to be discussed. Motivational interviewing (MI) was used as a counseling technique.

The number of sessions and the items discussed were registered by the counselors. Adherence to MI was determined by expert scoring of transcripts of random segments of 19 counseling sessions. Counselors' competence was rated by participants and counselors separately. Associations between three process indicators and body weight at follow-up were determined by linear and logistic regression analyses.

Two-thirds of all participants attended five or more sessions, and 38.5% attended all seven sessions. In 90.2% of all cases, the counselor discussed all obligatory items in the first session. MI adherence was reached in one audiotaped fragment. Most (86.3%) of all participants agreed with the counselor being competent. Neither counselors' competence nor number of sessions or items discussed was significantly associated with body weight loss.

Performing five sessions and discussing four prescribed items was feasible for the counselors, whereas performing MI was not. Still, participants were positive about the counselors' competence and willing to attend the intervention sessions. Investigators are encouraged to report the evaluation of their intervention process to improve future lifestyle interventions in research or in practice.