In a pooled analysis reported in JAMA Oncology, Yang et al found that higher fiber and higher yogurt consumption were associated with significantly reduced risk of lung cancer.
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Study Details
The analysis included 627,988 men (mean age = 57.9 years) and 817, 862 women (mean age = 54.8 years) from 10 prospective cohorts in the United State, Europe, and Asia. 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 from analyses.
Lung Cancer Risk
During median follow-up of 8.6 years (excluding the first 2 years after enrollment), 18,822 incident lung cancer cases were identified.
In analysis adjusted for smoking status, pack-years of smoking, and other lung cancer risk factors, higher fiber intake was associated with reduced risk for lung cancer, with a hazard ratio (HR) of 0.83 (95% confidence interval [CI] = 0.76–0.91; P < .001 for trend) for the highest quintile (31.0 g/day in men and 27.8 g/day in women) vs the lowest quintile (10.7 g/day in men and 10.2 g/day in women). For the total population, the number of lung cancer cases was 2,284 in the highest quintile vs 5,686 in the lowest quintile.
In adjusted analysis, high (> sex-specific median intake; median intake among all participants = 23.3 g/day) vs no yogurt intake was associated with significantly reduced risk of lung cancer, with a HR of 0.81 (95% CI = 0.76–0.87; P < .001 for trend).
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The associations of fiber and yogurt intake with reduced risk for lung cancer were consistent across sex, race/ethnicity, and tumor histologic type. The combination of high yogurt consumption and highest quintile of fiber intake was associated with a HR of 0.67 (95% CI = 0.61–0.73) in the total study population, suggesting a potential synergistic effect. In analysis by smoking status, HRs were 0.74 (95% CI = 0.67–0.83; P = .04 for interaction) among current smokers, 0.66 (95% CI =0.59–0.73; P = .45 for interaction) among former smokers, and 0.69 (95% CI = 0.54–0.89; P = .02 for interaction) among never smokers for the highest fiber intake plus yogurt consumption vs the lowest fiber intake without yogurt consumption.
The investigators concluded, “In this large pooled analysis, after adjusting for a wide range of known or putative lung cancer risk factors, we found that dietary fiber and yogurt consumption were both associated with reduced risk of lung cancer. For the first time to our knowledge, a potential synergistic association between fiber and yogurt intakes on lung cancer risk was observed…our findings suggest a potential protective role of prebiotics and probiotics against lung carcinogenesis.”
Xiao-Ou Shu, MD, PhD, of the Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was supported by grants from the National Institutes of Health. For full disclosures of the study authors, visit jamanetwork.com.
