phytosterols and Lung-Neoplasms

(1) Background: In China and South Asia,

Topics: A549 Cells; Alstonia; Antineoplastic Agents; Betulinic Acid; Carcinoma, Non-Small-Cell Lung; Cell Proliferation; Humans; Lung Neoplasms; Pentacyclic Triterpenes; Phytosterols; Plant Extracts; Plant Leaves; Sterols; Tetrazolium Salts; Thiazoles; Triterpenes; Ursolic Acid

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; G2 Phase Cell Cycle Checkpoints; Humans; Lactones; Lung Neoplasms; M Phase Cell Cycle Checkpoints; Membrane Potential, Mitochondrial; Mitochondria; Phytosterols; Reactive Oxygen Species

Despite lung-specific in vitro and in vivo studies that support a chemopreventive role for phytoestrogens, there has been little epidemiologic research focused on dietary intake of phytoestrogens and risk of lung cancer.. To examine the relationship between dietary intake of phytoestrogens and risk of lung cancer.. Ongoing US case-control study of 1674 patients with lung cancer (cases) and 1735 matched healthy controls. From July 1995 through October 2003, participants were personally interviewed with epidemiologic and food frequency questionnaires to collect demographic information and to quantify dietary intake of 12 individual phytoestrogens.. Risk of lung cancer, estimated using unconditional multivariable logistic regression analyses stratified by sex and smoking status and adjusted for established and putative lung cancer risk factors.. Reductions in risk of lung cancer tended to increase with each increasing quartile of phytoestrogen intake. The highest quartiles of total phytosterols, isoflavones, lignans, and phytoestrogens were each associated with reductions in risk of lung cancer ranging from 21% for phytosterols (odds ratio [OR], 0.79; 95% confidence interval [CI], 0.64-0.97; P = .03 for trend) to 46% for total phytoestrogens from food sources only (OR, 0.54; 95% CI, 0.42-0.70; P<.001 for trend). Sex-specific effects were also apparent. For men, statistically significant trends for decreasing risk with increasing intake were noted for each phytoestrogen group, with protective effects for the highest quartile of intake ranging from 24% for phytosterols (OR, 0.76; 95% CI, 0.56-1.02; P = .04 for trend) to 44% for isoflavones (OR, 0.56; 95% CI, 0.41-0.76; P<.001 for trend), while in women, significant trends were only present for intake of total phytoestrogens from food sources only, with a 34% (OR, 0.66; 95% CI, 0.46-0.96; P = .01 for trend) protective effect for the highest quartile of intake. The apparent benefits of high phytoestrogen intake were evident in both never and current smokers but less apparent in former smokers. In women, statistically significant joint effects were evident between hormone therapy use and phytoestrogen intake. Specifically, high intake of the lignans enterolactone and enterodiol and use of hormone therapy were associated with a 50% (OR, 0.50; 95% CI, 0.31-0.68; P = .04 for interaction) reduction in risk of lung cancer.. While there are limitations and concerns regarding case-control studies of diet and cancer, these data provide further support for the limited but growing epidemiologic evidence that phytoestrogens are associated with a decrease in risk of lung cancer. Confirmation of these findings is still required in large-scale, hypothesis-driven, prospective studies.

Topics: Aged; Case-Control Studies; Diet; Diet Surveys; Female; Food; Humans; Isoflavones; Lignans; Logistic Models; Lung Neoplasms; Male; Middle Aged; Phytoestrogens; Phytosterols; Risk Factors; Smoking; United States

Plant sterols are substances present in vegetable oils, corn and some fruits. According to previous studies, phytosterols are protective in colon carcinogenesis. This case-control study was carried out in order to establish a possible protective role of plant sterols in lung carcinogenesis. The study was performed in Montevideo, Uruguay, during 1993-1996, and included 463 cases with lung cancer and 465 hospitalized controls. Total plant sterol intake was associated with a reduction in risk of 50% when contrasting the upper exposure quartile with the lower, after controlling for major confounders, including tobacco smoking and total energy intake. This protective effect was specially evident in adenocarcinoma of the lung (OR 0.29, 95% CI 0.14-0.63). Therefore, plant sterol intake appears to be an important variable in lung carcinogenesis. Further studies are needed in order to replicate the present findings.

Topics: Adenocarcinoma; Adult; Age Distribution; Aged; Aged, 80 and over; Anticarcinogenic Agents; Case-Control Studies; Diet; Female; Humans; Lung Neoplasms; Male; Middle Aged; Phytosterols; Risk; Surveys and Questionnaires; Uruguay