Cardiovascular disease and smoking: efforts should be continued to reduce smoking prevalence

Cardiovascular disease (CVD) was the leading cause of death both globally and in the U.S. in 2019, with stroke and ischemic heart disease responsible for roughly 27% of total deaths worldwide. Tobacco use is one of the major preventable causes of death. There were 1.14 billion current smokers in the world and 7.69 million died from smoking in 2019.

We conducted a study to investigate the global CVD burden attributable to smoking from 1990 to 2019 using the global burden of disease (GBD) study. Smoking did not include smokeless tobacco, electronic cigarettes, etc. (Please see the paper for detailed CVD and smoking definitions).

We found that the age-standardized mortality rate (ASMR) of smoking-attributed CVD decreased from 1990 to 2019. In 2019, ischemic heart disease was the leading cause of smoking-attributed CVD deaths followed by stroke. Additionally, countries and territories are categorized into five sociodemographic index (SDI) quintiles in the GBD study (SDI is a measure of the development status). ASMR decreased in all SDI regions, but the greatest decrease was seen in the high SDI region, such that the high SDI region had the lowest ASMR in 2019. Eastern Europe had the highest ASMR, Andean Latin America had the lowest ASMR and the U.S. ranked 105 out of 204 countries/territories in terms of the highest ASMR in 2019.

There is a need, both at an individual patient-physician level as well as public policy level, to reduce smoking prevalence. Our data showed that males had higher ASMRs than females in all 204 countries or territories and higher death rates across all age groups in 2019. Sex-based differences in smoking behaviors, as well as the effects of smoking on cardiovascular outcomes, have also been shown. This indicates that sex-specific approaches (i.e., targeted messaging and campaigns, tailored support programs) to tobacco control and management of smoking-attributed CVD are warranted.

Smoking-attributed CVD death rate decreased across the age groups, including 70 years or older, between 1990 and 2019. However, it has previously been shown in a study that older patients (>65 years) in the U.S. were less likely to receive smoking cessation prescriptions. Targeted interventions and increased physician awareness are needed to improve outcomes among older patients.

There were several limitations in our study including but not limited to variations in quality, accuracy of the data from various regions, reporting bias and overlapping uncertainty intervals of estimates of subgroups. However, our study has important implications to guide public health policy. There has been a significant improvement in the global prevalence of smoking. Many efforts have been made to fight the tobacco epidemic, including but not limited to marketing restrictions, increased taxation, media campaigns to promote cessation, and smoke-free air laws. However, there have been significant geographic variations in smoking attributed to the CVD burden. Although the results are encouraging, our work is far from done.

In the U.S., cigarette smoking causes more than 480,000 deaths each year. In the U.S., 11.5% of adults were current cigarette smokers in 2021 and these results varied by different subgroups (e.g., decreased with increasing education as well as increasing annual household income). Current cigarette smoking (i.e., people who reported smoking at least 100 cigarettes during their lifetime and who, at the time they participated in a survey about this topic, reported smoking every day or some days) declined from 20.9% in 2005 to 11.5% in 2021.

To improve health outcomes, we need to have a multifaceted approach and work on all the contributing factors to morbidity and mortality. Our study focused specifically on smoking-attributed CVD burden. As noted above, our study did not include e-cigarettes. In 2021, 4.5% of U.S. adults were e-cigarette users (up from 3.7% in 2020) and the use was highest among 18-24 year olds (11.0%). Previously, an increase in substance use + cardiovascular disease-related mortality has also been documented in the U.S. Recently, cardiovascular-kidney metabolic syndrome was described. In the U.S, shockingly, only 17.35%, 5.45% and 1.8% of the population aged 20-44, 45-64, and 65+ had stage 0 CKM (stage 0 CKM defined as not overweight/obese and without metabolic risk factors (hypertension, hypertriglyceridemia, metabolic syndrome, prediabetes, diabetes), chronic kidney disease or cardiovascular disease).

Continued efforts toward the prevention of all the risk factors are paramount.

By Dr. Abdul Mannan Khan Minhas, preventive cardiology fellow at Baylor College of Medicine