Smokeless tobacco and increased risk of hypopharyngeal and laryngeal cancers: A multicentric case-control study from India

Hypopharyngeal and laryngeal cancers are among the most common cancers in India. In addition to smoking, tobacco chewing may be a major risk factor for some of these cancers in India. Using data from a multicentric case-control study conducted in India that included 513 hypopharyngeal cancer cases, 511 laryngeal cancer cases and 718 controls, we investigated smoking and chewing tobacco products as risk factors for these cancers. Bidi smoking was a stronger risk factor compared to cigarette smoking for cancer of the hypopharynx (OR bidi 6.80 vs. ORcig 3.82) and supraglottis (OR bidi 7.53 vs. ORcig 2.14), while the effect of the 2 products was similar for cancer of the glottis (ORbidi 5.32 vs. ORcig 5.74). Among never-smokers, tobacco chewing was a risk factor for hypopharyngeal cancer, but not for laryngeal cancer. In particular, the risk of hypopharyngeal cancer increased with the use of Khaini (OR 2.02, CI 0.81-5.05), Mawa (OR 3.17, CI 1.06-9.53), Pan (OR 3.34, CI 1.68-6.61), Zarda (OR 3.58, CI 1.20-10.68) and Gutkha (OR 4.59, CI 1.21-17.49). A strong dose-response relationship was observed between chewing frequency and the risk of hypopharyngeal cancer (ptrend < 0.001). An effect of alcohol on cancer of the hypopharynx and supraglottis was observed only among daily drinkers (OR 2.22, CI 1.11-4.45 and OR 3.76, CI 1.25-11.30, respectively). In summary, this study shows that chewing tobacco products commercially available in India are risk factors for hypopharyngeal cancer, and that the potency of Bidi smoking may be higher than that of cigarette smoking for hypopharyngeal and laryngeal cancers. \ua9 2007 Wiley-Liss, Inc

Indoor air pollution from solid fuels and risk of hypopharyngeal/ laryngeal and lung cancers: A multicentric case - Control study from India

Background: A recent monograph by the International Agency for Research on Cancer (IARC) has identified indoor air pollution from coal usage as a known human carcinogen, while that from biomass as a probable human carcinogen. Although as much as 74% of the Indian population relies on solid fuels for cooking, very little information is available on cancer risk associated with these fuels in India. Methods: Using data from a multicentric case-control study of 799 lung and 1062 hypopharyngeal/laryngeal cancer cases, and 718 controls, we investigated indoor air pollution from various solid fuels as risk factors for these cancers in India. Results: Compared with never users, individuals who always used coal had an increased risk of lung cancer [odds ratio (OR) 3.76, 95% confidence interval (CI) 1.64-8.63]. Long duration of coal usage (>50 years) was a risk factor for hypopharyngeal (OR 3.47, CI 0.95-12.69) and laryngeal (OR 3.65, CI 1.11-11.93) cancers. An increased risk of hypopharyngeal cancer was observed among lifelong users of wood (OR 1.62, CI 1.14-2.32), however this was less apparent among never-smokers. Increasing level of smokiness inside the home was associated with an increasing risk of hypopharyngeal and lung cancer (Ptrend< 0.05). Conclusion: This study showed differential risks associated with indoor air pollution from wood and coal burning, and provides novel evidence on cancer risks associated with solid fuel usage in India. Our findings suggest that reducing indoor air pollution from solid fuels may contribute to prevention of these cancers in India, in addition to tobacco and alcohol control programs. \ua9 The Author 2008; all rights reserved

Dietary risk factors for hypopharyngeal cancer in India

Objective: The Indian subcontinent has among the highest rates of hypopharyngeal cancer worldwide. The purpose of this study was to examine the associations between the Indian diet and hypopharyngeal cancer. Methods: We used data from a hospital-based case-control study of 513 incident hypopharyngeal cancers and 718 controls from four centers in India. Dietary information was assessed using a 67-item semi-quantitative food frequency questionnaire. Intakes of related foods were combined across food groups and were categorized by quartile. We used unconditional logistic regression modeling, stratified by ever tobacco use, to analyze the association between food intakes and hypopharyngeal cancer. Results: Among persons who had ever smoked or chewed tobacco, protective associations were seen at the highest quartiles of total fruit intake (OR = 0.37, 0.20-0.69), curds (OR = 0.35, 0.17-0.69), and leafy green (OR = 0.25, 95% CI 0.13-0.51), root (OR = 0.22, 95% CI 0.11-0.43), and cruciferous vegetable intakes (OR = 0.41, 0.20-0.84). Results were similar, although not as robust, among persons who had never smoked or chewed tobacco. An increased risk of disease was seen among tobacco users who drank milk daily (OR = 1.84, 1.14-2.98). Conclusions: Dietary factors might contribute to the high risk of hypopharyngeal cancer observed in India. © 2008 Springer Science+Business Media B.V