Talc-coated rice as a risk factor for stomach cancer

Our plain-English summary of Talc-coated rice as a risk factor for stomach cancer, by G.N. Stemmermann, L.N. Kolonel (The American Journal of Clinical Nutrition, 1978).

The study

• Authors: G.N. Stemmermann, L.N. Kolonel
• Journal: The American Journal of Clinical Nutrition
• Published: 1978;31(11):2017-9
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002153).

Abstract

Analysis of data from Japan and Hawaii offers no support for the hypothesis that the use of talc-coated rice increases the risk of developing stomach cancer. This conclusion is based on the observation that Japanese in Japan have very high rates of stomach cancer but consume no talc-coated rice, that Japanese in Hawaii have intermediate rates of stomach cancer but consume considerable amounts of talc-coated rice, and that Filipinos in Hawaii have very low rates of gastric cancer but consume the highest amounts of talc-coated rice of these three groups. Furthermore, secular trends in gastric cancer incidence show a much greater decrease in the incidence of this tumor among the exposed Japanese in Hawaii than among the unexposed Japanese in Japan.

In plain English

This short report tested the idea that talc used to coat rice, possibly contaminated with asbestos, causes stomach cancer among Japanese people. The article reports no measurements of talc or asbestos. The authors compared published, age-adjusted stomach cancer incidence rates for Miyagi and Okayama in Japan, where they assumed no coated rice was eaten, with rates for ethnic groups in Hawaii, where they assumed coated rice was eaten by everyone. They also used a Hawaii nutrition survey (first 10,000 interviews) that asked how often rice was eaten each week. Filipinos in Hawaii ate rice most often (men 11.8 times a week) but had very low stomach cancer rates (men 9.7 and 8.5 per 100,000 in the two periods). Rates among Japanese men in Hawaii fell 27% (47.6 to 34.9 per 100,000). Rates among men in Okayama stayed high (93.9 and 90.3 per 100,000 in 1962 to 1964 and 1968 to 1971). The authors concluded that there was no positive association between exposure to talc-coated rice and stomach cancer risk. They noted that Filipino rates, especially for women, rested on too few cases to judge trends reliably.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Ecological comparison of published, age-adjusted population stomach cancer incidence rates in Japan and Hawaii for two time periods, combined with rice-eating frequency from a Hawaii dietary survey
• Who was studied: Indigenous Japanese in Miyagi and Okayama, Japan (1962 to 1964 and 1968 to 1971). Japanese, Filipino, Caucasian and Hawaiian/part-Hawaiian populations in Hawaii (1960 to 1964 and 1968 to 1972). Rice intake came from the first 10,000 interviews of a survey based on an annual random sample of 3% of Hawaii's population.
• Exposure: Talc-coated rice (talc possibly contaminated with asbestos, per the hypothesis tested; no fiber type is named). Exposure was not measured. The authors assumed coated rice was eaten by everyone in Hawaii and by no one among Japanese in Japan, and used weekly rice-eating frequency.
• Main results:
  • Mean rice intake per week in Hawaii, age-adjusted:
• Filipinos: men 11.8 ± 0.23 (707 men), women 11.0 ± 0.25 (589 women)
• Japanese: men 8.9 ± 0.14 (1401), women 7.6 ± 0.12 (1480)
• Hawaiians: men 8.3 ± 0.34 (409), women 7.1 ± 0.27 (454)
• Caucasians: men 3.2 ± 0.11 (1600), women 2.8 ± 0.10 (1581)
  • Stomach cancer rates for Filipinos in Hawaii were very low:
• Men: 9.7 per 100,000 (27 cancers) in 1960 to 1964 and 8.5 (26 cancers) in 1968 to 1972
• Women: 1.5 (1 cancer) and 6.4 (6 cancers)
  • Among men in Japan, rates per 100,000 were stable at a high level in Okayama (93.9 in 1962 to 1964 and 90.3 in 1968 to 1971). In Miyagi they went from 95.3 to 84.6, which the authors describe as a modest decrease of 11.2%.
  • Stomach cancer rates in Hawaii fell between the two periods by 27% among Japanese men (47.6 to 34.9 per 100,000) and by 42% among Hawaiian/part-Hawaiian men (45.9 to 26.6).
  • Japanese women in Hawaii showed a 19% decline (26.9 to 21.8 per 100,000). Hawaiian/part-Hawaiian women's rates were stable (24.5 and 25.3). Women in Japan had rates of 45.7 and 48.3 in Okayama, and 44.7 and 40.1 in Miyagi.
• The authors' conclusion: The authors concluded that there is no positive association between how often people were exposed to talc-coated rice and their level of stomach cancer risk. They wrote that the suggestion that heavy exposure to talc-coated rice accounts for stomach cancer rates appears to be refuted by these data.
• Limitations the authors state:
  • Filipino rates, especially for women, were based on too few cases to reliably assess trends over time.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Stomach cancer, Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Talc, Stomach Cancer.

Related studies

• Talc-treated rice and Japanese stomach cancer — R.R. Merliss (1971)
• Talc exposure and risk of stomach cancer: Systematic review and meta-analysis of occupational cohort studies — C.J. Chang, Y.K. Tu, et al. (2020)
• Exposure to nitrosamines, carbon black, asbestos, and talc and mortality from stomach, lung, and laryngeal cancer in a cohort of rubber workers — K. Straif, U. Keil, et al. (2000)
• Stomach Cancer and Exposure to Talc Powder without Asbestos via Chinese Herbal Medicine: A Population-Based Cohort Study — C.J. Chang, Y.H. Yang, et al. (2019)
• Asbestos, talc and nitrites in relation to gastric cancer — W.E. Smith (1973)
• Occupational risk factors for mortality from stomach and lung cancer among rubber workers: an analysis using internal controls and refined exposure assessment — K. Straif, L. Chambless, et al. (1999)

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