In summary, clinicians and individuals should focus at- tention on living a healthy lifestyle by referring to these evidence-based recommendations to help pre- vent ASCVD. 1.1. Methodology and Evidence Review This guideline continues the ACC and AHA effort to de- sign a comprehensive yet succinct compilation of practi- cal guidance for the primary prevention of ASCVD and to promote optimal dissemination of information by us- ing concise language and formatting. The recommen- dations listed in this guideline are evidence based and supported by an extensive evidence review. A search for literature derived from research involving human sub- jects, published in English, and indexed in Ovid MED- LINE, PubMed, Cochrane Library, National Institute for Health and Care Excellence (NICE), and other selected databases relevant to this guideline, was conducted be- tween May and July 2018. For specific search terms used and years searched per section, please see Appendix 1. Randomized controlled trials (RCTs), systematic re- views of RCTs, meta-analyses, and large, United States based, high-quality cohort studies, as well as observa- tional studies and systematic reviews of observational studies, were evaluated for their content on the pre- vention of ASCVD outcomes related to the following 9 topic areas: risk assessment, diet, exercise/physical ac- tivity, obesity and weight loss, type 2 diabetes mellitus (T2DM), blood cholesterol, hypertension, smoking ces- sation, and aspirin use. Previous ACC/AHA guidelines, as well as US Preventive Services Task Force (USPSTF) reviews and other guidance relevant to this guideline, were also assessed. The final evidence tables included in the Online Data Supplement summarize the evidence used to formulate recommendations. References se- lected and published in this document are representa- tive and not all-inclusive. Avalere Health, a healthcare advisory services firm contracted by ACC/AHA, served as the document manager for this guideline to facilitate its development process. 