Behavioral Counseling Interventions to Promote a Healthy Diet and Physical Activity for Cardiovascular Disease Prevention in Adults Without Known Cardiovascular Disease Risk Factors: Updated Systematic Review for the U.S. Preventive Services Task Force [Internet]

Excerpt

Objective: We conducted this systematic review to support the U.S. Preventive Services Task Force (USPSTF) in updating its 2017 recommendation on behavioral counseling to promote a healthy diet and physical activity in adults without known CVD risk factors.

Data Sources: We performed a search of MEDLINE, PsycINFO, and the Cochrane Central Register of Controlled Trials for studies published through February 3, 2021. Studies included in the 2017 USPSTF review were re-evaluated for potential inclusion. We supplemented searches by examining reference lists from related articles and expert recommendations. We conducted active surveillance of the literature through October 6, 2021.

Study Selection: Two researchers reviewed 7,485 titles and abstracts and 411 full-text articles against prespecified inclusion criteria. We included English-language randomized clinical trials of behavioral interventions targeting improved diet, increased physical activity, decreased sedentary time, or a combination of these targets among adults without known hypertension, dyslipidemia, diabetes, impaired fasting glucose or glucose tolerance, or a combination of these factors. Studies among adults who were overweight or had obesity were included. Data were extracted from studies by one reviewer and checked by a second.

Data Analysis: Random effects meta-analysis was used to examine outcomes with sufficient evidence to warrant pooled analyses, including blood pressure, lipids, fasting blood glucose, adiposity-related outcomes, dietary measures, and physical activity. Subgroup analyses and meta-regression were used to explore effect modification. Data on health outcomes and harms were sparsely reported, and the specific outcomes measured differed across trials, precluding meta-analysis.

Results: One-hundred and thirteen randomized clinical trials were included (N=129,993). Three trials reported long-term outcomes related to mortality or cardiovascular events:. One large dietary counseling study (n=47,179) found no differences between groups on any CVD outcome at up to 13.4 years follow-up whereas as a combined analysis of the other two physical activity studies (n=1,203) found a statistically significant intervention association with nonfatal (HR = 0.27 [95% CI, 0.08 to 0.88]) and fatal (HR = 0.31 [95% CI, 0.11 to 0.93]) CVD events at 4 years. Fifteen trials reported quality of life outcomes, but few demonstrated statistically significant, nor clinically significant, changes in quality of life following the interventions. Diet and physical activity behavioral interventions were associated with small, statistically significant reductions in continuous measures of blood pressure, LDL cholesterol, adiposity-related outcomes at 6 months to 1.5 years of followup versus control conditions. Blood pressure improved by an average of 0.8/0.4 mm Hg (pooled systolic blood pressure=-0.8 [95% CI, −1.3 to −0.3]; 23 RCTs [n=57,079]; I²=11%; pooled diastolic blood pressure=-0.4 [95% CI, −0.8 to −0.0]; 24 RCTs [n=57,148]; I²=36%). Low-density lipoprotein cholesterol was reduced by an average of 2.2 mg/dL (95% CI, −3.8 to −0.6; 15 RCTs [n=10,122]; I²=69%). Intervention groups also showed slightly greater reductions in three adiposity-related measures: pooled body mass index=-0.3 kg/m² (95% CI, −0.5 to −0.1); 27 RCTs (n=59,239); I²=95%; and pooled waist circumference=-0.8 cm (95% CI, −1.3 to −0.3); 23 RCTs (n=52,128); I²=96%. There was evidence of a dose-response effect, with an association between increasing intervention intensity and larger improvements in intermediate outcomes. Very few studies reported the effects of the interventions beyond 12 months.

There was also consistent evidence that behavioral interventions improved participants’ dietary intake and physical activity levels. Meta-analysis indicated statistically significant associations between healthy diet counseling interventions (with or without physical activity messages) and measures of saturated fat (standardized mean difference [SMD], −0.5 [95% CI, −0.8 to −0.3]; 16 RCTs [n=48,661]; I²=97%), fiber (SMD, 0.2 [95% CI, 0.1 to 0.4]; 13 RCTs [n=47,571]; I²=94%), and daily servings of fruits and vegetables (1.1 [95% CI, 0.4 to 1.8]; 17 RCTs [n=53,711]; I²=99%). Physical activity interventions (with or without dietary components) resulted in an approximate 33-minute increase in physical activity per week compared with controls (33.0 minutes/week [95% CI, 21.9 to 44.2]; 37 RCTS [n=15,015]; I²=76%) and had a 41 percent higher odds of meeting physical activity recommendations compared with those in the control group (odds ratio= 1.4 [95% CI, 1.2 to 1.7]; 24 trials [n=17,338]; I²=55%). Adverse events were rare and there was no evidence of greater harm among intervention groups.

Limitations: Health outcomes such as cardiovascular events and quality of life were only reported in a few included trials. Measurement of behavioral outcomes was extremely heterogeneous.

Conclusions: The results of this systematic review update are consistent with the 2017 review on this topic. Healthy diet and physical activity behavioral interventions for persons without a known risk of CVD were associated with very small but statistically significant benefits across a variety of important intermediate health outcomes and small-to-moderate effects on dietary and physical activity behaviors. Very limited evidence exists regarding the health outcomes or harmful effects of these interventions.