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The National Cancer Institute's (NCI) , which can calculate an individual's risk for death over the coming years, is now more accurate thanks to the inclusion of smoking history, researchers reported.

If smoking status isn't taken into account, the mortality risks are underestimated for smokers and overestimated for nonsmokers, according to Steven Woloshin, MD, MS, of the Geisel School of Medicine at Dartmouth in Lebanon, New Hampshire, and colleagues.

As they found in their cohort study in , the chance of death due to major causes like heart disease, lung cancer, and all causes combined varies by smoking status. After age 40, for example, the observed effect of never versus current smoking on the 10-year chance of death due to all causes approximates adding 10 years of age, the researchers said. After age 40 years when "conditioning" on smoking status, the mortality risk for Black individuals was approximately that of white individuals 5 years older.

Regardless of sex or race, for never-smokers, coronary heart disease represented the highest 10-year chance of death after about age 50, which is higher than for any cancer, the team reported. Among current smokers, the 10-year chance of death due to lung cancer was almost as high as for coronary heart disease in each group.

In addition, Woloshin and co-authors said, for Black and white female smokers in their mid-40s and older, the 10-year probability of death due to lung cancer was substantially higher than for breast cancer.

The aim of the "Know Your Chances" website is to help people understand their personal risk for cancer and non-cancer deaths. The site contains several interactive charts, which previously used just race, age, and sex.

The previous version of the site included a disclaimer: "The charts do not account for some individual characteristics that affect the chance of death, most importantly smoking. Smoking substantially increases the chance of dying from heart attacks, stroke, lung cancer, chronic lung disease, and all-causes combined. If you smoke, your chances of dying from these causes are higher than those shown in the charts -- and if you never smoked, your chances of dying are lower."

Woloshin and co-authors were involved with the creation of the site, which launched in 2015. The new model to create charts now includes options for current, former, and never smokers.

Shireen Khoury, MD, MPH, of Johns Hopkins Medicine in Baltimore, who was not involved with the study, told 乌鸦传媒 that taking a personal approach to understanding the risks of smoking can have widespread benefits.

"So much is individualized when it comes to understanding and refining personal risk and developing the right care plan -- there is truly no 'one size fits all' approach," she said. "Patients vary in terms of what they find motivating or valuable on the path to become non-smokers, and that has to guide our shared decisions in clinic. These interactive risk estimators can be one item in a toolkit for patients and physicians to consider -- access to the data is important. Ultimately, though, the information might be more useful on a population level than on an individual level."

In terms of smoking, Khoury added that patients can vary substantially regarding the types of tobacco products used, patterns of use, and even genetic factors that affect susceptibility to developing stronger or long-term nicotine dependence. "There is no known 'safe' type or level of tobacco use. It is important to understand the nuance of an individual patient's history with tobacco to select the right tools and develop a plan together," she said.

A total of 954,029 participants were included in the analysis. All patients were ages 55 or older, and 55.8% of the study population were women.

The researchers calculated mortality estimates using life table methods from the NCI's software package, combining data from the U.S. National Vital Statistics System, National Health Interview Survey–Linked Mortality Files, NIH–AARP, Cancer Prevention Study II, Nurses' Health and Health Professions follow-up studies, and the Women's Health Initiative. Data were collected from Jan. 1, 2009, to Dec. 31, 2018, and analyzed from Aug. 27, 2019, to Feb. 28, 2023.

Study limitations, the researchers said, included that the data predated the COVID-19 pandemic and that the revised charts do not account for other risk factors such as drug or alcohol use, obesity, family history, genetic risks, or the presence of various diseases.

"In theory, charts tailored to a wide variety of risk factors might provide more personalized risk estimates. However, reliable risk models are not available for many of the risk factors alone or in combinations, and, consequently, extensive tailoring would introduce substantially more uncertainty. Our estimates would serve as useful inputs to researchers attempting to create more personalized estimates," Woloshin and co-authors wrote.

This article has been updated to reflect that the "Know Your Chances" site now accounts for smoking history.

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