Even occasional smoking can harm health and substantially raise the risk of cardiovascular disease, according to a new analysis. Researchers report that people who smoke as few as two cigarettes per day had a 57% higher risk of heart failure and a 60% higher risk of death from any cause compared with never-smokers. The study’s authors emphasized that quitting as early as possible is the best prevention strategy, noting that risks fall considerably within the first decade after cessation but can remain elevated for decades.

Study details and findings
Johns Hopkins University investigators pooled data from more than 300,000 adults enrolled in 22 longitudinal studies, with some participants followed for nearly 20 years. During follow-up the researchers recorded about 125,000 deaths and 54,000 cardiovascular events, including heart attacks, strokes, and heart failure.

They defined “low-intensity smoking” as two to five cigarettes per day and found this level was associated with markedly higher cardiovascular risk and mortality versus never smoking. The team concluded the main public-health message should be early cessation rather than merely reducing cigarette count, because low-intensity smoking still causes significant harm.

Why even a few cigarettes matter
Cardiologists and other experts not involved in the research called the study robust and impactful. They explained that cardiovascular harm from smoking is not linear: the first cigarettes produce a large share of the damage. Mechanisms include platelet activation, endothelial dysfunction, and vasospasm — changes that can occur with very low tobacco exposure and that promote clots, vessel narrowing, and heart stress.

Experts highlighted the importance of this message for younger adults and occasional smokers: no amount of smoking is safe, and even infrequent use sharply increases the risk of premature death and heart disease.

Trends, public-health context, and long-term risk
The study was motivated in part by changing smoking patterns. The American Lung Association reports adult cigarette use in the U.S. fell from about 42% in 1965 to 12% in 2022, yet the proportion of adults smoking fewer than 15 cigarettes per day has increased substantially. As more people smoke less rather than quitting, understanding the risks of low-intensity smoking and the benefits of quitting remains important.

The Centers for Disease Control and Prevention (CDC) estimates more than 16 million Americans live with a smoking-related disease. Cigarette smoking and secondhand smoke cause more than 480,000 deaths annually in the U.S., nearly one in five deaths. Beyond heart disease, smoking contributes to over 10 types of cancer, lung disease, COPD, asthma, type 2 diabetes, and eye diseases.

Although quitting yields substantial risk reductions, former smokers can still show elevated cardiovascular risk even decades after quitting. The study found the biggest drop in risk occurs within the first 10 years of cessation, with continued decline over time, but some excess risk may persist after 30 years.

Who smokes and who wants to quit
Nearly 50 million U.S. adults use tobacco products, and tobacco remains the leading preventable cause of disease and death. Groups with higher smoking prevalence include adults aged 45–64, non-Hispanic American Indian or Alaska Native adults, people with disabilities, and people with severe generalized anxiety disorder or severe depression. E-cigarette use is most common among adults 18–24.

A CDC survey in 2022 found about two-thirds of people who smoke want to quit, and more than half had tried to quit in the previous year.

Quitting strategies and support
Stopping smoking is challenging, and experts recommend combining behavioral support with medical aids for the best chance of success. Evidence-based strategies include:

– Setting a quit date and identifying triggers
– Stress-management techniques and practical replacement plans
– Nicotine replacement therapies (patches, gum, lozenges, nasal spray) and prescription medications to reduce cravings
– Professional counseling, behavioral therapies, and support groups
– Involving friends and family for encouragement and practical help, such as distraction techniques and patience during relapses

Clinicians stress that quitting often requires multiple attempts and that relapse is part of the process, not a failure. Tailoring approaches to individual needs and combining medication with behavioral support yields the highest long-term quit rates.

Bottom line
This large pooled analysis reinforces that there is no safe level of smoking. Even very low-intensity or occasional cigarette use significantly increases the risk of heart failure, cardiovascular events, and death. The clearest health advice remains to never start smoking, and for current smokers to stop as early as possible using effective medical and behavioral supports.

Even an occasional cigarette can endanger a person’s health and raise their risk of cardiovascular disease, a new analysis finds. Researchers report that people who smoke as few as two cigarettes per day have a 57% higher risk of heart failure and a 60% higher risk of death from any cause compared with people who have never smoked.

The study, published November 18 in PLOS Medicine, pooled data from more than 300,000 adults enrolled in 22 longitudinal studies, with some participants followed for nearly 20 years. During that time researchers recorded about 125,000 deaths and 54,000 cardiovascular events, including heart attacks, strokes, and heart failure. The investigators defined “low-intensity smoking” as two to five cigarettes per day and found a substantial increase in cardiovascular risk even at that low level.

Authors say risks fall substantially within the first decade after quitting and continue to decrease over time, but former smokers can still exhibit elevated risk even three decades after quitting. Their primary public health message: early cessation, not simply cutting back, is the best strategy.

Experts not involved in the research called the findings robust and important. Kevin Shah, MD, a cardiologist and heart failure program director, said the study provides compelling evidence that even low levels of cigarette smoking substantially increase cardiovascular disease and premature death. Cheng-Han Chen, MD, an interventional cardiologist, emphasized the persistent negative impact of smoking on public health.

The investigators were motivated in part by shifting smoking patterns: while adult smoking prevalence in the U.S. fell from about 42% in 1965 to roughly 12% in 2022, the proportion of people who smoke fewer than 15 cigarettes per day has grown. Michael Blaha, MD, MPH, a study author, noted that as more people “smoke less” rather than quit, understanding the cardiovascular risks of low-intensity smoking and the long-term benefits of quitting is important.

Cardiologists stress there is no safe level of smoking. Jayne Morgan, MD, said the first few cigarettes may cause a disproportionately large amount of cardiovascular damage because smoking quickly triggers platelet activation, endothelial dysfunction, and vasospasm — mechanisms that promote heart attacks and strokes even at very low exposure. Chen urged younger adults to recognize that even occasional smoking significantly raises the chance of death or heart disease, and that quitting early is the most important action for long-term health.

Public health context and other harms
The Centers for Disease Control and Prevention reports that more than 16 million Americans live with a smoking-related disease. Smoking contributes to more than 10 types of cancer, chronic lung disease, COPD, asthma, type 2 diabetes, and some eye diseases. Cigarette smoking and secondhand smoke exposure cause more than 480,000 deaths each year in the U.S., nearly one in five deaths.

Nearly 50 million U.S. adults use tobacco products, and tobacco remains the leading cause of preventable disease and death. Groups with higher smoking prevalence include people aged 45–64, non-Hispanic American Indian or Alaska Native adults, people with disabilities, and those with severe anxiety or depression. Adults 18–24 have the highest prevalence of e-cigarette use.

Quitting and support
About two-thirds of people who smoke want to quit, and more than half reported trying to quit in the prior year. Health organizations recommend combining behavioral support with medical aids for the best chance of success. Effective strategies include:

– Setting a quit date and identifying smoking triggers
– Building confidence and motivation to quit
– Stress management and replacement plans for smoking rituals
– Medications and nicotine-replacement therapies such as patches, gum, lozenges, and nasal spray
– Counseling, therapy, and structured behavioral programs
– Getting support from friends, family, or quit groups

Clinicians note quitting often requires multiple attempts; relapse is common and not a sign of failure. Tailoring a combination of approaches to individual needs yields the highest likelihood of quitting for good. Family and friends can help by being patient, understanding triggers, offering distractions, and providing appropriate encouragement.

Bottom line
The new pooled analysis reinforces that even very low-intensity cigarette smoking — as few as two cigarettes a day — is associated with a markedly higher risk of heart failure and premature death. The clearest public health message is that there is no safe level of smoking and that early and sustained cessation is the best way to reduce cardiovascular and other health risks.