The Healthy Lifestyle Index (HLI) integrates key behaviours to assess their cumulative impact on health. While higher HLI adherence is linked to lower disease and mortality risk, its long-term trajectory association remains understudied. This study aims to examine the dose-response relationship and long-term association of HLI on mortality risks.

Systematic review and dose-response meta-analysis using the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.

PubMed, Scopus and Web of Science were searched until June 2024.

We included observational cohort studies that assessed the relationship of HLI or its trajectories with all-cause, cardiovascular disease (CVD)-cause or cancer-cause of mortality.

Analysis of 13.7 million participants demonstrated that higher adherence to the HLI is linked to lower risk of all-cause (HR: 0.48; 95% CI 0.46 to 0.53; GRADE: moderate), CVD-cause (HR: 0.49; 95% CI 0.44 to 0.51; GRADE: moderate) and cancer-cause mortality (HR: 0.55; 95% CI 0.49 to 0.61; GRADE: low). These associations were further confirmed in a dose-response manner. Moreover, compared with maintaining an unhealthy lifestyle, a decline in HLI adherence was associated with a 14% higher risk of all-cause and a 19% higher risk of cancer-related mortality. In contrast, an improvement in HLI adherence was linked to a 20% lower risk of all-cause and a 13% lower risk of cancer-related mortality.

Adherence to HLI and its long-term patterns are associated with lower mortality risk. These findings emphasise the importance of lifestyle-based prevention and intervention strategies in reducing mortality.

CRD42024500538.