Background Gender social norms are the unspoken ‘rules’ through which individuals enact their gender, and biased gender social norms have been recognised as harmful to health. However, research in this area has focused on issues predominantly related to reproductive health. Cardiovascular disease (CVD) is the leading cause of mortality globally. Therefore, understanding how gender social norms may be associated with CVD mortality rates and life expectancy requires exploration.

Methods We used an ecological study design with country as the unit of analysis. Outcome measures included age-standardised CVD mortality rates and life expectancy at birth both stratified by sex. Gender social norms were quantified at country level by the United Nations Gender Social Norms Index (GSNI), based on the World Values Survey wave 2005–2009 and 2010–2014. Multivariable linear regression models were fitted to explore the relationship between GSNI and the outcome variables. Covariates in the models were GDP per capita, population mean years of schooling, physicians per 1000 population, wave of GSNI data collection and maternal mortality ratio. Data for 2014, or closest year available, were retrieved from the WHO, Institute for Health Metrics and Evaluation, Our World in Data and the World Bank. Sensitivity analyses were undertaken using data from 2017 and 2019. Analysis was conducted using R version 4.1.2.

Results Higher country levels of biased gender social norms were associated with higher female (β 4.86, 95% CIs 3.21 to 6.51), male (β 5.28, 95% CIs 3.42 to 7.15) and population (β 4.89, 95% CIs 3.18 to 6.60) CVD mortality rates in the multivariable models, and lower female and male life expectancy (β -0.07, 95% CIs -0.11 to -0.04; β -0.05, 95% CIs -0.10 to -0.01). The sensitivity analyses demonstrated no change in the direction of association between each outcome variable and the GSNI, however, the association with male life expectancy in 2019 was not statistically significant.

Conclusion Our results suggest that higher country levels of biased gender social norms are associated with higher population-level rates of CVD mortality and lower life expectancy for both females and males. Limitations include challenges in quantifying gender social norms and risk of unmeasured confounding. Whilst ecological studies cannot explore causality, these findings justify further investigation into gender social norms as a phenomenon that may impact on the entire population’s health, particularly in the area of non-communicable diseases.