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Original Investigation
October 24, 2019

Association of Dietary Fiber and Yogurt Consumption With Lung Cancer Risk: A Pooled Analysis

Author Affiliations
  • 1Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt University Medical Center, Nashville, Tennessee
  • 2State Key Laboratory of Oncogene and Related Genes & Department of Epidemiology, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
  • 3Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
  • 4Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, Washington
  • 5Department of Exercise and Nutrition Sciences, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia
  • 6Division of Epidemiology & Genetics, National Cancer Institute, Bethesda, Maryland
  • 7Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, St Louis, Missouri
  • 8College of Public Health and Human Sciences, Oregon State University, Corvallis
  • 9Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis
  • 10Masonic Cancer Center, University of Minnesota, Minneapolis
  • 11Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
  • 12Department for Determinants of Chronic Diseases, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
  • 13Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, the Netherlands
  • 14Department of Odontology, Umeå University, Umeå, Sweden
  • 15Cancer Registry and Histopathology Department, Civic-M.P. Arezzo Hospital, American Samoa, Ragusa, Italy
  • 16Faculty of Medicine, School of Public Health, Imperial College, London, United Kingdom
  • 17Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark
  • 18Denmark Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
  • 19Department of Community Medicine, UIT, The Arctic University of Norway, Tromsø, Norway
  • 20Public Health Directorate, Asturias, Spain
  • 21Genetic Epidemiology Group, International Agency for Research on Cancer, Lyons, France
  • 22Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
  • 23Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
JAMA Oncol. Published online October 24, 2019. doi:https://doi.org/10.1001/jamaoncol.2019.4107
Key Points

Question  Does an association exist between risk of lung cancer and habitual intakes of dietary fiber (the main source of prebiotics) or yogurt (a probiotic food)?

Findings  In this pooled analysis of more than 1.44 million individuals from the United States, Europe, and Asia, high intakes of dietary fiber or yogurt were individually associated with reduced risk of lung cancer, independent of all known risk factors. A potential synergistic association of fiber and yogurt consumption with lung cancer risk was also observed.

Meaning  Dietary fiber and yogurt may be individually and jointly associated with reduced risk of lung cancer.


Importance  Dietary fiber (the main source of prebiotics) and yogurt (a probiotic food) confer various health benefits via modulating the gut microbiota and metabolic pathways. However, their associations with lung cancer risk have not been well investigated.

Objective  To evaluate the individual and joint associations of dietary fiber and yogurt consumption with lung cancer risk and to assess the potential effect modification of the associations by lifestyle and other dietary factors.

Design, Setting, and Participants  This pooled analysis included 10 prospective cohorts involving 1 445 850 adults from studies that were conducted in the United States, Europe, and Asia. Data analyses were performed between November 2017 and February 2019. Using harmonized individual participant data, hazard ratios and 95% confidence intervals for lung cancer risk associated with dietary fiber and yogurt intakes were estimated for each cohort by Cox regression and pooled using random-effects meta-analysis.Participants who had a history of cancer at enrollment or developed any cancer, died, or were lost to follow-up within 2 years after enrollment were excluded.

Exposures  Dietary fiber intake and yogurt consumption measured by validated instruments.

Main Outcomes and Measures  Incident lung cancer, subclassified by histologic type (eg, adenocarcinoma, squamous cell carcinoma, and small cell carcinoma).

Results  The analytic sample included 627 988 men, with a mean (SD) age of 57.9 (9.0) years, and 817 862 women, with a mean (SD) age of 54.8 (9.7) years. During a median follow-up of 8.6 years, 18 822 incident lung cancer cases were documented. Both fiber and yogurt intakes were inversely associated with lung cancer risk after adjustment for status and pack-years of smoking and other lung cancer risk factors: hazard ratio, 0.83 (95% CI, 0.76-0.91) for the highest vs lowest quintile of fiber intake; and hazard ratio, 0.81 (95% CI, 0.76-0.87) for high vs no yogurt consumption. The fiber or yogurt associations with lung cancer were significant in never smokers and were consistently observed across sex, race/ethnicity, and tumor histologic type. When considered jointly, high yogurt consumption with the highest quintile of fiber intake showed more than 30% reduced risk of lung cancer than nonyogurt consumption with the lowest quintile of fiber intake (hazard ratio, 0.67 [95% CI, 0.61-0.73] in total study populations; hazard ratio 0.69 [95% CI, 0.54-0.89] in never smokers), suggesting potential synergism.

Conclusions and Relevance  Dietary fiber and yogurt consumption was associated with reduced risk of lung cancer after adjusting for known risk factors and among never smokers. Our findings suggest a potential protective role of prebiotics and probiotics against lung carcinogenesis.

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