Background: Poor diet and lack of physical activity can worsen cardiovascular health, yet most Americans do not meet diet and physical activity recommendations.
Purpose: To assist the U.S. Preventive Services Task Force in updating its previous recommendations by systematically reviewing trials of physical activity or dietary counseling to prevent cardiovascular disease.
Data sources: MEDLINE, PsycINFO, Cochrane Central Register of Controlled Trials (2001 to January 2010), experts, and existing systematic reviews.
Study selection: Two investigators independently reviewed 13 562 abstracts and 481 articles against a set of a priori inclusion criteria and critically appraised each study by using design-specific quality criteria.
Data extraction and analysis: Data from 73 studies (109 articles) were abstracted by one reviewer and checked by a second reviewer. Random-effects meta-analyses were conducted for multiple intermediate health and behavioral outcomes.
Data synthesis: Long-term observational follow-up of intensive sodium reduction counseling showed a decrease in the incidence of cardiovascular disease; however, other direct evidence for reduction in disease morbidity is lacking. High-intensity dietary counseling, with or without physical activity counseling, resulted in changes of -0.3 to -0.7 kg/m(2) in body mass index (adiposity), -1.5 mm Hg (95% CI, -0.9 to -2.1 mm Hg) in systolic blood pressure, -0.7 mm Hg (CI, -0.6 to -0.9 mm Hg) in diastolic pressure, -0.17 mmol/L (CI, -0.09 to -0.25 mmol/L) (-6.56 mg/dL [CI, -3.47 to -9.65 mg/dL]) in total cholesterol level, and -0.13 mmol/L (CI, -0.06 to -0.21 mmol/L) (-5.02 mg/dL [CI, -2.32 to -8.11 mg/dL]) in low-density lipoprotein cholesterol level. Medium- and high-intensity counseling resulted in moderate to large changes in self-reported dietary and physical activity behaviors.
Limitations: Meta-analyses for some outcomes had large statistical heterogeneity or evidence for publication bias. Only 11 trials followed outcomes beyond 12 months.
Conclusion: Counseling to improve diet or increase physical activity changed health behaviors and was associated with small improvements in adiposity, blood pressure, and lipid levels.
Primary funding source: Agency for Healthcare Research and Quality.