Why Is Lung Cancer Rising When Fewer People Smoke? Smoking, Lung Cancer Types, and What You Can Do for Your Lungs, Checked Against National Data and Studies

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Japan’s male smoking rate fell from 83.7% in 1966 to 27.8% in 2018 (JT “National Survey of Smoking Rates”). In the 2024 national survey, 14.8% of people aged 20 and over smoked habitually (24.5% of men, 6.5% of women) (MHLW “National Health and Nutrition Survey”).

Even so, deaths from lung cancer kept rising and reached a record 76,663 in 2022. They are still above 75,000 a year, and lung cancer is the leading cause of cancer death (National Cancer Center Japan, Cancer Statistics).

Some people ask, “If more people have quit smoking and lung cancer is still rising, doesn’t that mean tobacco has nothing to do with it?”

This article uses national statistics and studies to check:

• Why lung cancer seems to be rising even though fewer people smoke
• How the link to smoking differs by lung cancer type (adenocarcinoma, squamous cell carcinoma, small cell carcinoma, and others)
• What is known about the causes of lung cancer in people who do not smoke
• How solid the evidence is for actions, foods, and habits said to be good for the lungs

Conclusion

• The number of people who die of lung cancer has risen, but the death rate compared at the same ages has been falling since its 1996 peak. The age-adjusted death rate fell 33% for men and 21% for women between 1996 and 2024
• The biggest reason for the rise in numbers is population aging. The share of lung cancer deaths in people aged 75 and over rose from 23% in 1975 to 70% in 2024. If the 1996 age-specific death rates were applied to the 2024 population, deaths would be about 92,000, but the actual figure was about 76,000
• There is a time lag of 20 years or more between smoking and lung cancer. The generations that smoked heavily are now old enough for lung cancer. The lung cancer death rate for men in their 50s and 60s fell by roughly 40% to 60% between 1996 and 2024
• The strength of the link to smoking differs by type of lung cancer. Squamous cell carcinoma and small cell carcinoma are especially strongly linked to smoking: in a Japanese study, male smokers had about 12 times the risk of squamous cell carcinoma of non-smokers. Adenocarcinoma is common in non-smokers too, and smoking raises its risk by a smaller factor, about 2
• As smokers have decreased, squamous cell carcinoma and small cell carcinoma have declined, and adenocarcinoma is now the most common. Adenocarcinomas found at an early stage are increasing in particular, and easier detection through screening is thought to be part of the reason
• Lung cancer in people who do not smoke is linked to secondhand smoke (rated “convincing” by the National Cancer Center Japan), workplace asbestos (“probable”), air pollution (PM2.5), radon, cooking fumes, and more
• The actions with clear evidence for your lungs are quitting smoking (at any age) and avoiding secondhand smoke. Fruit, vegetables, and exercise are at the “possibly lowers risk” level, and beta-carotene supplements are known to raise lung cancer in smokers
• Heated tobacco has fewer harmful substances than cigarettes in many cases, but more of some, and its link to lung cancer is “unable to judge”, according to the May 2026 summary by an MHLW research group

Smoking rates and lung cancer over time

(Age-adjusted death rates are per 100,000 people. The 2024 smoking rate is from the MHLW “National Health and Nutrition Survey, Reiwa 6 (2024)”; it was collected differently from the JT survey.)

If you look only at the top two graphs, it seems that “smoking fell but lung cancer rose.” The bottom graph, the age-adjusted death rate, tells a different story.

Analysis: why lung cancer seems to rise when smokers are decreasing

① Aging: the numbers rise, but at the same ages the rate has fallen

Cancer becomes more common with age. When there are more older people, the number of people with cancer rises even if each person’s risk stays the same.

The age-adjusted death rate removes the effect of differences in age structure so that years can be compared. The age-adjusted lung cancer death rate (men and women combined) peaked at 27.4 in 1996 and fell to 19.9 in 2024 (27% lower).

If the 1996 age-specific death rates were applied as they are to the 2024 population, lung cancer deaths would be about 92,000. The actual 2024 figure was about 76,000. In other words, the chance of getting (and dying of) lung cancer at each age has fallen, and the numbers rose because the number of older people grew so much.

② Time lag: the effects of smoking appear after 20 years or more

It takes a long time from starting to smoke to developing lung cancer. In countries such as the UK and the US, where smoking rates are past their peak, men’s lung cancer rates have followed the same shape as smoking rates and began to fall 20 to 25 years later (review by Shong 2025). A Japanese study also points to a “long time lag” between starting to smoke and dying of lung cancer (Funatogawa 2013).

Looking by age group shows this time lag clearly.

(Calculated from National Cancer Center Japan, Cancer Statistics)

• In the 50s and 60s, rates have fallen sharply since 1996. These are the generations in which fewer people smoke
• At 85 and over, rates kept rising until 2015 and only then began to fall. This is thought to be because the generations who were adults when about 80% of men smoked have been reaching these ages
• A study of the Osaka cancer registry also reported that lung cancer incidence by birth cohort “runs almost parallel to smoking rates” (Toyoda 2008)

The reason lung cancer does not fall right away even though there are fewer smokers now is that tobacco’s harm takes time to show up. Much of today’s lung cancer reflects smoking decades ago.

③ More lung cancers are being found: especially early-stage adenocarcinoma

Besides deaths, let us also look at the number of people newly diagnosed with lung cancer.

(Per 100,000 people. Figures through 2015 are national estimates; from 2016 they are from the National Cancer Registry, which collects data differently. From 2016 to 2023, incidence was roughly flat at 120,000 to 126,000 a year.)

• The age-adjusted incidence rate for women rose about 2.5 times from 1975 to 2015, but the age-adjusted death rate rose only from 8.3 to 11.1 (about 1.3 times)
• A study combining three Japanese cancer registries (Nguyen 2022, 1993–2015) found that early-stage adenocarcinoma, where the cancer is still confined within the lung, increased by 4.5% a year in men and 5.7% a year in women. The authors suggest that improved testing (diagnostic methods) making these cancers easier to find may be involved
• In Taiwan, where fewer than 5% of women smoke, early-stage lung cancer rose more than sixfold once low-dose CT screening became widespread. Advanced-stage lung cancer did not decrease and death rates did not change, so the analysis concluded that most of the increase was “overdiagnosis” (finding cancers that would not threaten life) (Gao 2022)

The rise in newly found lung cancers includes not only an actual increase in disease but also a change in how cancers are found.

④ Lung cancer weakly linked to smoking: lung cancer in people who do not smoke

Lung cancer is often thought of as a “smoker’s disease,” but people who do not smoke get it too.

• The JACC Study, which pooled three large Japanese follow-up studies, found that the share of lung cancer deaths attributable to smoking was 67% in men and 15% in women (Wakai 2005)
• A study of 876 Japanese patients who had surgery for non-small cell lung cancer found that 435 (about half) had never smoked (Kawaguchi 2016)

As smokers decrease, the share of lung cancer occurring in people who do not smoke grows. The causes of lung cancer in non-smokers are covered in the next section.

Summary of the analysis

Types of lung cancer and their link to smoking

Lung cancer is classified by the shape of the cancer cells under a microscope (histological type). According to the National Cancer Center Japan, adenocarcinoma is common in women and non-smokers too, while squamous cell carcinoma and small cell carcinoma are strongly associated with smoking.

How many times higher is the risk with smoking

(The figures from Pesch et al. are odds ratios. It is known that in Japanese people the rise in lung cancer risk from smoking is smaller than in Westerners.)

• Pooling the Japanese studies, smokers’ risk of lung cancer overall is about 4.4 times that of non-smokers for men and about 2.8 times for women (Wakai 2006)
• In Pesch et al., risk began to fall early after quitting, but they reported that even after 35 years it did not become the same as that of non-smokers

Fewer smokers changed the mix of types

• In the Osaka cancer registry, from the 1990s the incidence of squamous cell carcinoma and small cell carcinoma fell while adenocarcinoma kept rising (Toyoda 2008)
• In three Japanese cancer registries (1993–2015), adenocarcinoma made up 35% of lung cancers in men and 58% in women, the most common type in both. In men, squamous cell carcinoma and small cell carcinoma were decreasing (Nguyen 2022)
• The national lung cancer screening guideline (fiscal 2025 edition) also decided not to recommend sputum testing, because squamous cell carcinoma near the entrance of the lung, which sputum tests used to detect, is decreasing as smoking rates fall

“Light cigarettes with filters” and adenocarcinoma

Among people who smoke, the share of adenocarcinoma has also grown. The US Surgeon General’s report (2014) concluded that cigarettes with tiny holes in the filter (ventilation holes) that lowered measured tar led to an increase in adenocarcinoma in smokers (as introduced in Song 2017).

• People think of it as a “light” cigarette and inhale deeper and more
• The smoke reaches deep into the lungs, where adenocarcinoma tends to form

This is the thinking. “Light cigarettes are safe” is not true.

Lung cancer in people who do not smoke: what is involved

• Healthy people’s lung tissue also contains some cells with EGFR gene mutations (18% of the tissue examined), and a mechanism has been reported in which PM2.5 acts on those cells to promote cancer (Hill 2023, Nature)
• A study of Japanese women who do not smoke also reported a link between hormone-related factors, such as the timing of menopause, and adenocarcinoma (Wilunda 2021)

What about heated tobacco

In the 2024 national survey, more than 40% of people who smoke (41.4% of men, 44.2% of women) use heated tobacco.

An MHLW research group reviewed studies from 2010 to 2025 and in May 2026 published its “Summary of Findings to Date on Heated Tobacco Products.”

“Unable to judge” does not mean “safe.” Not much time has passed since heated tobacco became widespread, and not enough time has passed to study its link to diseases such as lung cancer that take decades to develop.

The research group also excluded studies conducted or funded by tobacco companies from its judgments.

What you can do for your lungs: by strength of evidence

Actions, foods, and habits said to be “good for the lungs” are lined up here by the strength of assessments from national and international bodies.

Clear evidence

The same goes for lung function: people who quit smoking had a smaller decline in lung function than those who kept smoking, with the extra decline about 20% of that in continuing smokers (six US follow-up studies, Oelsner 2020). On the other hand, it is also known that for decades after quitting, decline is still slightly faster than in people who never smoked.

Possible (limited research)

• Fruit and vegetables: a pooled analysis of follow-up studies reported that for each additional 100 g a day, lung cancer was 8% lower for fruit and 6% lower for vegetables, and beyond about 400 g a day there was no further difference (Vieira 2016, analysis for WCRF). However, the link is clear mainly in current and former smokers, and the authors say that “residual confounding by smoking cannot be ruled out” and that “the best way to prevent lung cancer is to eliminate tobacco”
• Exercise: people with more leisure-time exercise had 24% less lung cancer, but there was no difference in non-smokers (Brenner 2016)
• Overall diet: one pooled analysis found less lung cancer with diets high in vegetables, fruit, and fish, and 32% more with a “Western” diet high in refined grains, red meat, and processed meat (Zhao 2023)

These are observational studies of what kinds of diets people with less lung cancer had. They do not let us say that “eating X prevents lung cancer.”

What to avoid

Beta-carotene eaten in vegetables and fruit has not been a problem. The problem arose with large amounts taken as supplements.

• Trial of 29,133 male smokers in Finland (ATBC): a supplement of 20 mg of beta-carotene a day led to 18% more lung cancer
• Trial of 18,314 US smokers and asbestos workers (CARET): 30 mg of beta-carotene plus vitamin A led to 28% more lung cancer, and the trial was stopped earlier than planned
• A pooled analysis of randomized trials also found 19% more lung cancer with beta-carotene supplements, and the authors say that “beta-carotene supplements are not recommended for cancer prevention” (Zhang 2023)

Quitting smoking makes far more of a difference than adding “lung-friendly ingredients” in supplements.

For people who want to quit smoking

Ways to quit, and what studies show

• Nicotine patches and gum are medicines. They cannot be used by people who are pregnant or breastfeeding, who have serious heart disease or acute-phase stroke, or who have been diagnosed with depression, among others. If you have a medical condition or take medicines, consult a doctor or pharmacist
• Nicotine patches (Category 1 medicines) involve a pharmacist’s check even when you buy online
• Switching to heated tobacco while trying to quit does not count as “quitting” above

Quit-smoking aids and a book (Rakuten Ichiba)

(Checked on the Rakuten Ichiba sales pages on September 29, 2026. Prices and shipping may change. For medicines, read the precautions carefully and follow the dosage and directions.)

Note The indicated effect of nicotine patches and gum is “relief of symptoms such as irritability, difficulty concentrating, and restlessness while quitting smoking.” They are not medicines that prevent lung cancer. If quitting does not go well, you can get advice at a smoking cessation clinic.

Adding fruit and vegetables to everyday meals

Fruit is one of the few foods that the National Cancer Center Japan assesses as “possibly lowering” lung cancer risk. In the studies, differences showed up at up to about 400 g a day (Vieira 2016). The targets in the national “Health Japan 21” are 350 g of vegetables and 200 g of fruit a day.

If it is hard to stock up on vegetables and fruit during daily shopping, one way is to check the quantity and contents with a trial set from a food delivery service. Differences in each company’s standards and fees are summarized in the food delivery comparison article.

Another way is to order fruit directly from the growing region. The sugars and fiber of citrus such as mandarin oranges and oranges are compared across 22 fruits in the fruit fructose article.

Note Food delivery or ordering fruit will not prevent lung cancer. The fruit and vegetable studies are observational, and the link was seen especially in current and former smokers. For people who smoke, the biggest thing is quitting.

Summary

• The number of lung cancer deaths has risen with aging, but the death rate at the same ages has been falling since 1996
• The effects of smoking appear 20 or more years later. The generations that smoked heavily are now old and reaching the age for lung cancer
• Among lung cancers, squamous cell carcinoma and small cell carcinoma are very strongly linked to smoking and are decreasing as smokers decrease. Adenocarcinoma, the most common, is common in non-smokers too, and secondhand smoke, air pollution, radon, constitution, and other factors are also involved. That tests now find early-stage adenocarcinoma is one reason many people are newly diagnosed
• The link between heated tobacco and lung cancer is still at the “unable to judge” stage
• What is certain for your lungs is quitting smoking (at any age) and avoiding secondhand smoke. Fruit, vegetables, and exercise are at the “possible” stage, and beta-carotene supplements backfire in smokers
• People aged 50 to 74 with a smoking index of 600 or more (including those who quit within 15 years) are recommended an annual low-dose CT screening

Sources

• National Cancer Center Japan, Cancer Information Service, “Cancer Statistics” tables (national cancer deaths 1958–2024, national cancer incidence 1975–2015, National Cancer Registry 2016–2023) https://ganjoho.jp/reg_stat/statistics/data/dl/index.html
• National Cancer Center Japan, Cancer Information Service, “Lung Cancer: Basics” https://ganjoho.jp/public/cancer/lung/about.html
• National Cancer Center Japan, Institute for Cancer Control, “List of Assessments of Cancer Risk and Preventive Factors” ver.20260526 https://epi.ncc.go.jp/can_prev/outcome/index.html
• National Cancer Center Japan, “Lung Cancer Screening Guideline Based on Evaluation of Effectiveness,” fiscal 2025 edition https://canscreen.ncc.go.jp/guideline/lung_guideline2025.pdf
• MHLW, “Summary of the Reiwa 6 (2024) National Health and Nutrition Survey” https://www.mhlw.go.jp/content/10900000/001603146.pdf
• MHLW, 5th Expert Committee on Secondhand Smoke Measures, Material 3, “Summary of Findings to Date on Heated Tobacco Products” (May 21, 2026) https://www.mhlw.go.jp/content/10904750/001702543.pdf
• JT, “National Survey of Smoking Rates” (1965–2018; table reprinted by Health Net https://www.health-net.or.jp/tobacco/statistics/jt.html )
• World Cancer Research Fund / AICR, “Diet, nutrition, physical activity and lung cancer” (CUP, 2017, revised 2018) https://www.wcrf.org/wp-content/uploads/2024/10/lung-cancer-report.pdf
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• Conditions for insurance coverage of smoking cessation treatment: Haleon Japan, “Ii Kin-en” https://www.e-kinen.jp/hospital/insurance.html
• Rakuten Ichiba sales pages for サンドラッグ “Nicotinell Patch 20, 14 patches,” 楽天24 ヘルスケア館 “Nicorette, 96 pieces,” and 楽天ブックス “禁煙セラピー” (checked September 29, 2026)