Abstract 3630: Fat intake interacts with cigarette smoking to alter lung cancer risk.

Abstract

Abstract Although cigarette smoking is the primary cause of lung cancer, it alone cannot explain large difference in risk of this malignancy worldwide. During the last three decades, age-adjusted male lung cancer mortality rates have been remarkably higher in Hungary than in Japan, but per capita cigarette consumption has remained lower in Hungary than in Japan. A similar pattern of difference has been observed between other Asian and western countries, (e.g., China, South Korea, Poland, and the US). It remains unclear why this lung cancer paradox occurs. Lung cancer incidence is generally high in countries with high intake of saturated fat. In addition, animal studies revealed a synergistic effect of fat and tobacco carcinogens on the development of lung tumors. Therefore, it is possible that different types of fat interact with cigarette smoking to modulate lung cancer risk. We sought to investigate this hypothesis in a hospital-based case-control study conducted from 2000 to 2005 in Nagoya, Japan. Cases (n=500), ages 20-79, were patients pathologically diagnosed with lung cancer at the Aichi Cancer Center. Controls (n=500) were recruited from visitors to the outpatient department of the same institution, and matched to cases by age (within 5 years) and sex. Fat intake was assessed with a validated food frequency questionnaire, and cigarette smoking was evaluated with a pre-tested risk factor questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using unconditional logistic regression. After adjustment for age, sex, BMI, energy intake, and alcohol drinking, lung cancer risk among heavy smokers (≥40 pack-years) decreased with increasing intake of monounsaturated fat (MUFA). Compared with never or light smokers (≤20 pack-years), ORs (95% CI) were 8.44 (4.53, 15.7), 4.34 (2.32, 8.13), and 3.63 (1.84, 7.04) for heavy smokers who were in the 1st(lowest), 2nd, and 3rd tertiles of MUFA intake, respectively. A similar pattern of interaction was present for intake of polyunsaturated fat (PUFA) and for moderate smokers (20-39 pack-years). To our knowledge, the present study is among the first to show that intake of unsaturated fat modifies the association between cigarette smoking and lung cancer risk, and thereby sheds new light on the etiology and prevention of this malignancy. Citation Format: Jianjun Zhang, Hideo Tanaka, Hidemi Ito, Keitaro Matsuo. Fat intake interacts with cigarette smoking to alter lung cancer risk. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3630. doi:10.1158/1538-7445.AM2013-3630