Smoking Even a Few Cigarettes a Day Raises Death Risk: Study

Steep Rise in Heart Failure, Stroke and All-Cause Mortality Among Light Smokers

November 25, 2025

A major new study has found that even light smoking dramatically increases the risk of serious heart conditions and early death, with women facing higher risk than men. The study involves decades of data from more than 320,000 (3.2 lakh) adults and offers the clearest long-term evidence to date that there is no safe level of tobacco use.

Published in the PLOS Medicine journal, revealed consistently higher risk of cardiovascular disease and death across all categories of smoking, as cited by NDTV. Men who currently smoked were 74 percent more likely to develop cardiovascular disease compared with men who had never smoked.

For women, the risk more than doubled. The pattern was just as severe when it came to all-cause mortality. Male smokers were 117 percent more likely to die from any cause, while female smokers faced a 143 percent higher risk than those who had never smoked. This aligns with other findings that suggest women may be more biologically vulnerable to the effects of tobacco, especially when it comes to heart disease.

People who smoked even a single cigarette per day faced significantly elevated health risks compared with non-smokers. Among those who smoked between two and five cigarettes daily, the risk of atrial fibrillation rose by 26 percent, heart failure by 57 percent and death from cardiovascular causes by 57 percent. All-cause mortality increased by 60 percent. For those consuming between 11 and 15 cigarettes daily, the risks rose even further – 87 percent higher for cardiovascular disease and 130 percent higher for death from any cause.

The numbers show the predictable breakdown of health over time, like wear and tear on a machine run with toxic fuel. A smoker may not notice problems early on, but the damage accumulates quietly and relentlessly. Doctors routinely see patients who believe their light smoking habit does not count as a real risk. A person might say they smoke only a few cigarettes a day and have done so for decades. Yet even five cigarettes per day over 40 years amounts to more than 70,000 cigarettes.

The study analysed data from 22 large-scale cohort studies under the Cross-Cohort Collaboration Tobacco Working Group. Researchers focused on three smoking-related factors: number of years an individual smoked, how many cigarettes they smoked per day, and how long it had been since they quit. These were tracked against health outcomes including heart attacks, strokes, heart failure, irregular heart rhythm (atrial fibrillation), other forms of cardiovascular disease and overall mortality.

The sample included 3,23,826 adults, most of whom were followed for decades, contributing over 25 million person-years of observation. Some participants were tracked for as long as 50 years.

The median age of participants was 60. Around 14 per cent were current smokers, 36 per cent had never smoked, and 50 per cent were former smokers. Women made up three-quarters of the study population. Among those still smoking, the average cigarette consumption was 20 per day. Former smokers had, on average, quit over two decades earlier.

The study’s scale gives its conclusions unusual weight. Most health research runs for a few years, sometimes less. In contrast, this project tracked participants over a period long enough to document not just early signs of illness but final outcomes, including heart failure, stroke and premature death.

The extended follow-up also allowed researchers to examine what happens after quitting. On average, former smokers in the study had given up smoking 21 years earlier. Their health outcomes were generally better than current smokers, but still worse than those who had never smoked. This confirms that quitting makes a difference, but it does not erase all past damage.

In terms of public health implications, the risk curve begins to rise with the very first cigarette and continues to climb. Social smokers, weekend smokers and those who believe that low-volume habits do not count are still exposed to measurable harm.

The risks are visible. And the solution, which is quitting completely and permanently, is both clear and possible. In the words of clinicians who deal with these cases every day, the earlier the exit, the better the chance of health returning. There is no harmless version of cigarette use, but there is a timeline that improves with every smoke-free year.

Though not part of the study, it is evident that in cities like Delhi, where air quality drops to severe or hazardous levels nearly every winter, the dangers extend far beyond smokers.

Prolonged exposure to high levels of ambient particulate pollution already strains the cardiovascular and respiratory systems, even in people who have never smoked. For those who continue to smoke under these conditions, the risks do not merely add up. They compound. The body’s defences are already compromised by toxic air, and cigarette smoke introduces a second, concentrated source of harmful chemicals. This dual exposure accelerates inflammation, damages blood vessels, and heightens the likelihood of heart attacks, strokes, and respiratory failure. In effect, smoking in high-AQI environments intensifies the body’s toxic burden, leaving it less able to recover or adapt, and pushing even low-level smokers into high-risk territory faster.

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