Importance: Unhealthful dietary patterns, low levels of physical activity, and high sedentary time increase the risk of cardiovascular disease.
Objective: To systematically review the evidence on the benefits and harms of behavioral counseling for the primary prevention of cardiovascular disease in adults without known cardiovascular risk factors to inform the US Preventive Services Task Force.
Data sources: MEDLINE, PubMed, Cochrane Central Register of Controlled Trials, and PsycINFO for studies published in the English language between January 1, 2013, and May 25, 2016, and ongoing surveillance in targeted publications through March 24, 2017. Studies included in the previous review were reevaluated for inclusion.
Study selection: Randomized clinical trials of behavioral interventions targeting improved diet, increased physical activity, decreased sedentary time, or a combination of these among adults without known hypertension, dyslipidemia, diabetes, or impaired fasting glucose.
Data extraction and synthesis: Independent critical appraisal and data abstraction by 2 reviewers.
Main outcomes and measures: Cardiometabolic health and intermediate outcomes, behavioral outcomes, and harms related to interventions.
Results: Eighty-eight studies (N = 121 190) in 145 publications were included. There was no consistent benefit of the interventions on all-cause or cardiovascular mortality or morbidity (4 trials [n = 51 356]) or health-related quality of life (10 trials [n = 52 423]). There was evidence of small, statistically significant between-group mean differences for systolic blood pressure (-1.26 mm Hg [95% CI, -1.77 to -0.75]; 22 trials [n = 57 953]), diastolic blood pressure (-0.49 mm Hg [95% CI, -0.82 to -0.16]; 23 trials [n = 58 022]), low-density lipoprotein cholesterol level (-2.58 mg/dL [95% CI, -4.30 to -0.85]; 13 trials [n = 5554]), total cholesterol level (-2.85 mg/dL [95% CI, -4.95 to -0.75]; 19 trials [n = 9325]), and body mass index (-0.41 [95% CI, -0.62 to -0.19]; 20 trials [n = 55 059]) at 6 to 12 months as well as small-to-modest associations with dietary and physical activity behaviors. There was no evidence of greater incidence of serious adverse events, injuries, or falls in intervention vs control participants.
Conclusions and relevance: Diet and physical activity behavioral interventions for adults not at high risk for cardiovascular disease result in consistent modest benefits across a variety of important intermediate health outcomes across 6 to 12 months, including blood pressure, low-density lipoprotein and total cholesterol levels, and adiposity, with evidence of a dose-response effect, with higher-intensity interventions conferring greater improvements. There is very limited evidence on longer-term intermediate and health outcomes or on harmful effects of these interventions.