Physical Activity in Relation to All-Site and Lung Cancer Incidence and Mortality in Current and Former Smokers

Exercise and survival benefit in cancer patients: evidence from a comprehensive meta-analysis

Cancer remains a major global health challenge, and growing evidence suggests that physical activity is a key modifiable factor that may improve survival outcomes in cancer patients. However, a comprehensive, large-scale synthesis of the effects of post-diagnosis physical activity across multiple cancer types remains lacking. This meta-analysis aims to systematically evaluate the association between physical activity and survival in patients diagnosed with breast, lung, prostate, colorectal, and skin cancers. We conducted a comprehensive search in PubMed, Web of Science, Scopus, and Cochrane Library for studies on physical activity and cancer survival. Eligible studies (January 2000-November 2024) included adults (≥ 18 years) with breast, lung, prostate, colorectal, or skin cancer. Only prospective cohort and case-control studies reporting hazard ratios (HRs) with 95% confidence intervals (CIs) for overall or cancer-specific mortality were included, with a minimum sample size of 100 and at least six months of follow-up. Meta-analysis was performed using metaanalysisonline.com, applying random-effects models and assessing heterogeneity via the I2 statistic. Sensitivity analyses and publication bias (Egger's test, funnel plots) were evaluated. The meta-analysis included 151 cohorts with almost 1.5 million cancer patients. Post-diagnosis physical activity was associated with significantly lower cancer-specific mortality across all five cancer types. The greatest benefit was observed in breast cancer, with a pooled hazard ratio (HR) of 0.69 (95% CI: 0.63-0.75), followed by prostate cancer (HR: 0.73, 95% CI: 0.62-0.87). Lung cancer patients who engaged in physical activity had a 24% lower risk of cancer-specific death (HR: 0.76, 95% CI: 0.69-0.84), while colorectal cancer patients experienced a similar benefit (HR: 0.71, 95% CI: 0.63-0.80). In skin cancer, physical activity was associated with a non-significant reduction in mortality (HR: 0.86, 95% CI: 0.71-1.05). These findings provide robust evidence supporting the survival benefits of post-diagnosis physical activity in cancer patients, particularly for breast, prostate, lung, and colorectal cancers. The results underscore the potential for incorporating structured physical activity interventions into oncological care to improve long-term patient outcomes.

Physical Activity, Air Pollution, and Mortality: A Systematic Review and Meta-analysis

BACKGROUND

As whether the positive effects of physical activity on mortality outweigh the negative effects of exposure to pollution is still under debate, we conducted a systematic review and meta-analysis on the risk of mortality for combined exposure to physical activity and air pollution.

METHODS

PubMed, Cochrane, Embase and ScienceDirect databases were searched for studies assessing the risk of mortality for combined exposure to physical activity and air pollution.

RESULTS

We included eight studies for a total of 1,417,945 individuals (mean 57.7 years old, 39% men) - 54,131 died. We confirmed that air pollution increased the risk of mortality by 36% (OR 1.36, 95CI 1.05-1.52), whereas physical activity in a non-polluted environment decreased the risk of mortality by 31% (OR 0.69, 95CI 0.42-0.95). Our meta-analysis demonstrated that combined exposure to physical activity and air pollution decreased the risk of mortality by 26% (OR 0.74, 95CI 0.63-0.85). This risk decreased whatever the level of physical activity: by 19% (OR 0.81, 95CI 0.69-0.93) for low, by 32% (OR 0.68, 95CI 0.44-0.93) for moderate, and by 30% (OR 0.70, 95CI 0.49-0.91) for high physical activity in air pollution.

CONCLUSION

We confirmed that air pollution increased mortality by 36% in our meta-analysis. Despite the controversial benefit-risk, we demonstrated a reduction of mortality by 26% for combined exposure to physical activity and air pollution - nearly comparable to the reduction of mortality when practicing physical activity without air pollution (- 31%). However, the limited number of included studies precluded the demonstration of a dose-response relationship between levels of physical activity and air pollution, and reduction of mortality.

Risk factors for early-onset lung cancer in Korea: analysis of a nationally representative population-based cohort

OBJECTIVES

We examined the associations of socioeconomic factors, health behaviors, and comorbidities with early-onset lung cancer.

METHODS

The study included 6,794,287 individuals aged 20-39 years who participated in a Korean national health check-up program from 2009 to 2012. During the follow-up period, 4,684 participants developed lung cancer. Multivariable Cox regression analysis was used to estimate the independent associations of potential risk factors with incident lung cancer.

RESULTS

Older age (multivariable hazard ratio [mHR], 1.13; 95% confidence interval [CI], 1.12 to 1.14) and female sex (mHR, 1.62; 95% CI, 1.49 to 1.75) were associated with increased lung cancer risk. Current smoking was also associated with elevated risk (<10 pack-years: mHR, 1.12; 95% CI, 1.01 to 1.24; ≥10 pack-years: mHR, 1.30; 95% CI, 1.18 to 1.45), but past smoking was not. Although mild alcohol consumption (<10 g/day) was associated with lower lung cancer risk (mHR, 0.92; 95% CI, 0.86 to 0.99), heavier alcohol consumption (≥10 g/day) was not. Higher income (highest vs. lowest quartile: mHR, 0.86; 95% CI, 0.78 to 0.94), physical activity for at least 1,500 metabolic equivalent of task-min/wk (vs. non-exercisers: mHR, 0.83; 95% CI, 0.69 to 0.99) and obesity (vs. normal weight: mHR, 0.89; 95% CI, 0.83 to 0.96) were associated with lower lung cancer risk, whereas metabolic syndrome was associated with increased risk (mHR, 1.13; 95% CI, 1.03 to 1.24).

CONCLUSIONS

In young adults, age, female sex, smoking, and metabolic syndrome were risk factors for early-onset lung cancer, while high income, physical activity, and obesity displayed protective effects.

Body mass index and prostate cancer risk in the Carotene and Retinol Efficacy Trial

The aim of this study was to investigate the association between BMI (kg/m) and prostate cancer risk. BMI is a modifiable lifestyle factor and may provide a unique opportunity for primary prevention of prostate cancer if a causal association exists. Data from 11 886 men from the Carotene and Retinol Efficacy Trial (CARET, 1985-1996 with active follow-up through 2005) comprising current and former heavy smokers were analyzed. CARET was a multicenter randomized, double-blind placebo-controlled chemoprevention trial testing daily supplementation of 30 mg β-carotene+25 000 IU retinyl palmitate for primary prevention of lung cancer. Prostate cancer was a secondary outcome. Nonaggressive disease was defined as Gleason less than 7 and stage I/II. Aggressive disease was primarily defined as at least Gleason 7 or stage III/IV, and secondarily by excluding Gleason 3+4 from the first definition. BMI was calculated from measured weight and height. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for cancer incidence between BMI categories. During follow-up, 883 men were diagnosed with prostate cancer. In the analysis of aggressive disease when Gleason 3+4 was excluded, men with a BMI of at least 35 kg/m had an increased rate of prostate cancer (HR: 1.80, 95% CI: 1.04-3.11, Ptrend=0.04) compared with men with BMI 18-24.9 kg/m. No other differences were seen in risk estimates for overall, nonaggressive or aggressive prostate cancer including all Gleason 7 cases, between BMI categories. Our results show an association between having a BMI of at least 35 kg/m and an increased risk of aggressive prostate cancer (not including Gleason 3+4 tumors), but do not support an association between BMI and risk of overall, aggressive disease including all Gleason 7, or nonaggressive prostate cancer within a population of current and former heavy smokers.

Habitual recreational physical activity is associated with significantly improved survival in cancer patients: evidence from the Roswell Park Data Bank and BioRepository

PURPOSE

The association of recreational physical activity (RPA) with mortality is well established only for breast and colon cancers and few studies have evaluated relationships for exercising before and after diagnosis, across multiple disease sites. We examined the joint associations of pre- and post- diagnosis RPA with mortality in a cohort of 5,807 patients enrolled in the Data Bank and BioRepository at Roswell Park.

METHODS

Patients were classified into one of four activity categories (habitually active, increased activity after diagnosis, decreased activity after diagnosis, habitually inactive). Cox proportional hazards models were used to estimate the associations of activity status with mortality.

RESULTS

In comparison to patients who were habitually inactive, habitually active patients experienced a 39% decreased hazard of all-cause mortality (HR = 0.61, 95% CI 0.54-0.69) and a 36% decreased hazard of cancer-specific mortality (HR = 0.64, 95% CI 0.56-0.73). Previously inactive patients who began exercising after diagnosis experienced a 28% decreased hazard of all-cause (HR = 0.72, 95% CI 0.59-0.89) and cancer-specific mortality (HR = 0.72, 95% CI 0.57-0.91) in comparison to patients who remained inactive. Patients engaging in 3-4 sessions/week experienced the greatest survival advantages, but 1-2 sessions/week also yielded significant survival advantages in comparison to inactivity.

CONCLUSION

Low-to-moderate frequency pre- and post-diagnosis RPA was associated with significantly decreased mortality in patients diagnosed with a variety of malignancies. These observations solidify the clinical and public health importance of the message that some regular activity is better than inactivity, which is particularly encouraging, given that cancer survivors can be overwhelmed by current daily physical activity recommendations.

LIFETIME PHYSICAL INACTIVITY IS ASSOCIATED WITH LUNG CANCER RISK AND MORTALITY

INTRODUCTION

Investigations of the independent associations of physical inactivity with cancer endpoints have been mounting in the epidemiological literature, in part due to the high prevalence of physical inactivity among cancer patients and to evidence that inactivity associates with carcinogenesis via pathways independent of obesity. Yet, physical inactivity is not currently recognized as a well-established risk or prognostic factor for lung cancer. As such, we examined the associations of lifetime physical inactivity with lung cancer risk and mortality in a hospital-based, case-control study.

PRESENTATION OF CASE

Materials and Methods: The analyses included data from 660 lung cancer patients and 1335 matched cancer-free controls. Multivariable logistic regression analyses were utilized to assess the association between lifetime physical inactivity and lung cancer risk, and Cox proportional hazards models were utilized to estimate the association between lifetime physical inactivity and mortality among lung cancer cases.Results: We observed a significant positive association between lifetime physical inactivity and lung cancer risk: [Odds ratio (OR)=2.23, 95% confidence interval (CI): 1.77-2.81]; the association remained significant among never smokers (OR=3.00, 95% CI:1.33-6.78) and non-smokers (OR=2.33, 95% CI: 1.79-3.02). We also observed a significant positive association between lifetime physical inactivity and lung cancer mortality [Hazard ratio (HR)=1.40, 95% CI: 1.14-1.71]; the association remained significant in non-smokers (HR=1.51, 95% CI: 1.16-1.95).

DISCUSSION/CONCLUSION

These data add to the body of evidence suggesting that physical inactivity is an independent risk and prognostic factor for cancer. Additional research utilizing prospectively collected data is needed to substantiate the current findings.

A case-control study of the association between self-reported occupational and recreational physical activity and lung cancer

This case-control study with a Fujian population investigated whether self-reported occupational and recreational physical activity may be associated with lung cancer.The population comprised 1622 patients with newly diagnosed primary lung cancer and 1622 age- and gender-matched healthy controls.High-intensity occupational physical activity was associated with significantly higher risk of lung cancer (OR = 1.354, 95% CI: 1.068-1.717), especially nonsmall cell lung carcinoma (OR = 1.384, 95% CI: 1.087-1.762). Moderate or low intensity recreational physical activity was associated with reduced risk of lung cancer. The protective effect of recreational physical activity was observed in current or former smokers, but not never-smokers, and in subjects with normal or high BMI, but not low BMI, as well as people without a history of chronic lung disease. The frequency of recreational physical activity was associated with a linear reduction in the risk of lung cancer (P < .001), and also specifically nonsmall cell lung cancer (P < .001).Occupational and recreational physical activity was associated with different effects on the risk of lung cancer in a Fujian population. While recreational physical activity was associated with decreased risk of lung cancer, occupational physical activity was associated with increased risk of lung cancer.

Sex-specific effects of leisure-time physical activity on cause-specific mortality in NHANES III

Associations between leisure time physical activity (LTPA) and all-cause mortality seem quite strong, however, less is known about the association of LTPA and cause-specific mortality. To examine this association data from the Third National Health and Nutrition Examination Survey (NHANES III), including 15,307 individuals of the non-institutionalized civilian United States population, were used. Data were collected from 1988 to 1994 with a mortality follow-up until 2006. LTPA was assessed during home interviews in which participants specified their LTPA and the performed frequency during the past month. Cox proportional hazards regression models were applied to analyze the risk of cause-specific mortality regarding LTPA. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed. An inverse association of LTPA with CVD mortality was observed for men and women combined for irregular (HR 0.66; 95% CI 0.51-0.85), and for regular activity (HR 0.58; 95% CI 0.47-0.72). An inverse association of LTPA with CVD mortality was observed only in women for irregular (HR 0.64; 95% CI 0.49-0.84) and for regular activity (HR 0.55; 95% CI 0.43-0.72). In men, no significant associations were seen. For mortality caused by respiratory diseases, a decreased mortality was also observed in the combined group (men and women) but after separating according to sex a decreased mortality was only observed in women. No statistically significant association of LTPA with cancer mortality was observed. Our data support an inverse association between LTPA and CVD and respiratory disease mortality in women, but not in men, and no associations with cancer.

Physical activity and sedentary behavior in relation to lung cancer incidence and mortality in older women: The Women's Health Initiative

Physical activity has been associated with lower lung cancer incidence and mortality in several populations. We investigated these relationships in the Women's Health Initiative Observational Study (WHI-OS) and Clinical Trial (WHI-CT) prospective cohort of postmenopausal women. The WHI study enrolled 161,808 women aged 50-79 years between 1993 and 1998 at 40 U.S. clinical centers; 129,401 were eligible for these analyses. Cox proportional hazards models were used to assess the association of baseline physical activity levels [metabolic equivalent (MET)-min/week: none <100 (reference), low 100 to <500, medium 500 to <1,200, high 1,200+] and sedentary behavior with total lung cancer incidence and mortality. Over 11.8 mean follow-up years, 2,148 incident lung cancer cases and 1,365 lung cancer deaths were identified. Compared with no activity, higher physical activity levels at study entry were associated with lower lung cancer incidence [p = 0.009; hazard ratios (95% confidence intervals) for each physical activity category: low, HR: 0.86 (0.76-0.96); medium, HR: 0.82 (0.73-0.93); and high, HR: 0.90 (0.79-1.03)], and mortality [p < 0.0001; low, HR: 0.80 (0.69-0.92); medium, HR: 0.68 (0.59-0.80); and high, HR: 0.78 (0.66-0.93)]. Body mass index (BMI) modified the association with lung cancer incidence (p = 0.01), with a stronger association in women with BMI < 30 kg/m(2) . Significant associations with sedentary behavior were not observed. In analyses by lung cancer subtype, higher total physical activity levels were associated with lower lung cancer mortality for both overall NSCLC and adenocarcinoma. In conclusion, physical activity may be protective for lung cancer incidence and mortality in postmenopausal women, particularly in non-obese women.

Intensity-specific effect of physical activity on urinary levels of 8-hydroxydeoxyguanosine in middle-aged Japanese

Physical activity (PA) is recommended to both promote and maintain health and prevent cancer by improving the body's DNA repair system, which is considered a mechanism of cancer prevention. However, associations between PA and urinary levels of 8-hydroxydeoxyguanosine (8-OH-dG), which reflects DNA damage, are unclear. This cross-sectional study included 2370 men and 4052 women aged 45-74 years enrolled between 2010 and 2012. Habitual PA was assessed by single-axis accelerometer and urinary 8-OH-dG levels by automated HPLC. Multiple linear regression analysis was used to examine the relationship between log-transformed urinary 8-OH-dG and total PA (TPA) and PA of moderate/vigorous intensity (MVPA; ≥3 metabolic equivalents), with adjustment for age, body mass index, energy intake, alcohol consumption, smoking status, daily coffee drinking, menopause status (in women), and TPA (for MVPA). On multivariate adjustment, urinary 8-OH-dG levels were inversely correlated with TPA (β = -0.020, P < 0.01) in women, and this correlation was not changed by PA intensity. Conversely, urinary 8-OH-dG levels were inversely correlated with MVPA (β = -0.022, P < 0.05) in men, although the correlation with TPA was non-significant. This inverse correlation was clearer in current smokers than in never or former smokers, although the interaction between smoking status and MVPA on urinary 8-OH-dG levels was non-significant. In conclusion, greater TPA in women and greater MVPA in men were correlated with reduction in urinary 8-OH-dG, suggesting sex-specific effects of MVPA and TPA on protection from oxidative DNA damage. Increasing PA may mediate reduction in oxidative stress.

Does smoking influence the physical activity and lung cancer relation? A systematic review and meta-analysis

Research suggests an inverse association between physical activity and lung cancer. However, whether the relation is modified by degree of smoking adjustment has not been summarized. We conducted a meta-analysis of physical activity and lung cancer focusing on evaluating whether smoking status and the degree of smoking adjustment influenced the association. Comparing high versus low physical activity levels from 25 observational studies yielded a lung cancer summary relative risk (RR) of 0.79 [95 % confidence interval (CI) = 0.72-0.87], with RRs of 0.87 (95 % CI = 0.80-0.94) for cohort studies and 0.57 (95 % CI = 0.46-0.71) for case-control studies. In further analyses restricted to cohort studies, physical activity was inversely related to lung cancer among former smokers (RR = 0.68, 95 % CI = 0.51-0.90) and current smokers (RR = 0.80, 95 % CI = 0.70-0.90), whereas the association was null among never smokers (RR = 1.05, 95 % CI = 0.78-1.40, p interaction = 0.26). The degree of smoking adjustment did not modify the association (p interaction = 0.73). Physical activity was unrelated to lung cancer among never smokers but it was inversely associated with lung cancer among former and current smokers. Although the physical activity and lung cancer relation was not modified by smoking status or degree of smoking adjustment, residual confounding by smoking remains a possible explanation for the relations observed.

Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence

Energy intake, physical activity, and obesity are modifiable lifestyle factors. This chapter reviews and summarizes the epidemiologic evidence on the relation of energy intake, physical activity, and obesity to cancer. High energy intake may increase the risk of cancers of colon-rectum, prostate (especially advanced prostate cancer), and breast. However, because physical activity, body size, and metabolic efficiency are highly related to total energy intake and expenditure, it is difficult to assess the independent effect of energy intake on cancer risk. There are sufficient evidences to support a role of physical activity in preventing cancers of the colon and breast, whereas the association is stronger in men than in women for colon cancer and in postmenopausal than in premenopausal women for breast cancer. The evidence also suggests that physical activity likely reduces the risk of cancers of endometrium, lung, and prostate (to a lesser extent). On the other hand, there is little or no evidence that the risk of rectal cancer is related to physical activity, whereas the results have been inconsistent regarding the association between physical activity and the risks of cancers of pancreas, ovary and kidney. Epidemiologic studies provide sufficient evidence that obesity is a risk factor for both cancer incidence and mortality. The evidence supports strong links of obesity with the risk of cancers of the colon, rectum, breast (in postmenopausal women), endometrium, kidney (renal cell), and adenocarcinoma of the esophagus. Epidemiologic evidence also indicates that obesity is probably related to cancers of the pancreas, liver, and gallbladder, and aggressive prostate cancer, while it seems that obesity is not associated with lung cancer. The role of obesity in other cancer risks is unclear.

Lifestyle, genes, and cancer

It is estimated that almost 1.5 million people in the USA are diagnosed with cancer every year. However, due to the substantial effect of modifiable lifestyle factors on the most prevalent cancers, it has been estimated that 50% of cancer is preventable. Physical activity, weight loss, and a reduction in alcohol use can strongly be recommended for the reduction of breast cancer risk. Similarly, weight loss, physical activity, and cessation of tobacco use are important behavior changes to reduce colorectal cancer risk, along with the potential benefit for the reduction of red meat consumption and the increase in folic acid intake. Smoking cessation is still the most important prevention intervention for reducing lung cancer risk, but recent evidence indicates that increasing physical activity may also be an important prevention intervention for this disease. The potential benefit of lifestyle change to reduce prostate cancer risk is growing, with recent evidence indicating the importance of a diet rich in tomato-based foods and weight loss. Also, in the cancers for which there are established lifestyle risk factors, such as physical inactivity for breast cancer and obesity for colorectal cancer, there is emerging information on the role that genetics plays in interacting with these factors, as well as the interaction of combinations of lifestyle factors. Integration of genetic information into lifestyle factors can help to clarify the causal relationships between lifestyle and genetic factors and assist in better identifying cancer risk, ultimately leading to better-informed choices about effective methods to enhance health and prevent cancer.