Trend of ischemic heart disease mortality attributable to metabolic, behavioral, and environmental risk factors in the past two decades
Authors: Aryan Z , Saeedi Moghaddam S , Ebrahimi H , Farzadfar F 
Published: October 2021

Abstract

Background
Ischemic heart diseases (IHD) is the leading cause of mortality, worldwide. Understanding of the status of risk factors contributing to IHD and mortality helps control this public health issue.

Purpose
This study aims to provide global, regional, and national estimates of the trend of IHD burden and deaths attributable to the modifiable risk factors, from 1990 to 2019.

Methods
Using the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 methodology, we evaluated the IHD incidence, mortality, years lived with disability, years of life lost, and disability-adjusted life-years (DALYs). IHD deaths attributable to the different metabolic, behavioral and environmental risk factors were estimated based on risk exposure, relative risks, and the theoretical minimum risk exposure level input from 204 countries and territories, stratified by sex and Socio-demographic Index (SDI). Trends were estimated from 1990 to 2019, with an emphasis on 2010 to 2019.

Results
Globally, there were 21·2 million (95% uncertainty interval [UI] 18·8–23·7) new cases, 9·1 million (8.4–9·7) deaths, and 182·0 million (170·2–193·5) DALYs due to IHD, in 2019. From 1990 to 2019, IHD incident cases, deaths and DALYs increased globally by 29.1·9% (27.0–31·3), 32·4% (25.3–37·8), and 53.9% (42·7–64·3), respectively. Although high SDI regions succeeded to reduce DLAYs due to IHDs by −36.7% (−33.8 to −39.2), low SDI regions faced an increase in DALYs due to IHDs by +104.4% (+75.0 to +135.3). In 2019, the five leading risk factors of deaths due to IHDs were; high systolic blood pressure [2.2 million deaths (1.7–2.7)], high LDL cholesterol [1.7 million deaths (1.2–2.3)], high fasting plasma glucose [1.1 million deaths (0.6–1.8)], high body-mass index [0.8 million deaths (0.5–1.1)], and diet low in whole grains [0.6 million deaths (0.2–0.8)]. From 1990 to 2019, high SDI regions succeeded to reduce the age standardized death rate of IHDs attributable to metabolic risk factors by −60.1% (−61.9 to −57.7), behavioral risk factors by −61.2% (−62.8 to −59.2) and environmental risk factors by −65.8% (−71.4 to −59.3). During the same period, the age standardized IHD death rate attributable to environmental risk factors decreased by −16.0% (−30.4 to −1.6), while the age standardized IHD death rate attributable to metabolic and behavioral risk factors didn't change significantly, in low SDI regions.

Conclusions
During the past two decades despite steadily increase in incident cases of IHDs, the age standardized burden of IHDs has decreased in high SDI regions most probably due to control of attributable risk factors. However, burden of IHDs has increased dramatically in low SDI regions. Preventive measures such as “polypills” for high blood pressure control programs and life-style modification should be prioritized in these settings.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): Bill & Melinda Gates Foundation Age-standardized DALY rates of IHD