Studies were eligible for the review if they were conducted in primary care in the USA and recruited participants from an underserved population (defined as individuals from minority ethnic backgrounds or vulnerable populations such as people with low educational attainment, low income, lack of insurance or those living in rural communities). Interventions had to include a specific component of counselling by primary care physicians. Studies had to have an appropriate control or comparison group, use a randomised or quasi-experimental design and report change in physical activity as an outcome.
The included studies used a wide variety of physical activity interventions and methods of delivering them. Participants were adolescents or adults. The percentage of females ranged from 37% to 100%. The proportion of participants who belonged to racial or ethnic minorities ranged from 15% to 100%. The proportion who were unemployed ranged from 11% to 65% (where reported) and the proportion with no college education or degree ranged from 11% to 65% (where reported). The intensity of counselling ranged from one to three minutes of contact on one occasion up to repeated sessions of more than five minutes. Most interventions included other components alongside counselling. All studies included a self-report measure of physical activity and some also used objective measures.
It appeared that one reviewer selected studies for the review.