Occupational risk factors for laryngeal carcinoma: Connecticut, 1975-1980

Our plain-English summary of Occupational risk factors for laryngeal carcinoma: Connecticut, 1975-1980, by R.T. Zagraniski, J.L. Kelsey, S.D. Walter (American Journal of Epidemiology, 1986).

The study

• Authors: R.T. Zagraniski, J.L. Kelsey, S.D. Walter
• Journal: American Journal of Epidemiology
• Published: 1986;124(1):67-76
• Cited by: 55 articles, 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. 000453).

Abstract

A case-control study of possible occupational risk factors for laryngeal carcinoma in white males in the New Haven, Connecticut, area included 92 cases diagnosed between 1975 and 1980 and 181 hospital controls individually matched to the cases on age, year and hospital of admission, county of residence, smoking status (current vs. ex-smoker), and type of tobacco used at the time of admission. Only cases and controls who were alive at the time of the study were included. With the effects of tobacco and alcohol controlled in a conditional linear logistic model, elevated odds ratios were found for men who had ever worked in rubber products manufacturing or transportation equipment manufacturing other than shipbuilding, and for men who had ever been machinists, bartenders, farmers, masons, or metal grinders. However, only one occupation, machinists, had a statistically significant odds ratio (2.5, 95% confidence interval = 1.2-5.2) in these multivariate analyses. Asbestos and nickel were not found to be risk factors for laryngeal carcinoma. Amount of tobacco smoked and alcohol consumed were positively associated with risk for laryngeal cancer.

In plain English

This case-control study looked for associations between possible occupational risk factors and cancer of the larynx (voice box) in white men around New Haven, Connecticut. It compared 92 men diagnosed in 1975-1980 with 181 hospital controls, all alive at the time of the study. Controls were matched on age, hospital, year of admission, smoking status, tobacco type, and county of residence or living within 25 miles of the case. Interviews covered job histories, and odds ratios for jobs and exposures were adjusted for tobacco and alcohol. Asbestos exposure was reported by 10.9 per cent of cases and 13.3 per cent of controls (odds ratio 0.8, 95 per cent confidence interval 0.4-1.7). Brake repairmen, asbestos workers and plumbers had odds ratios of 1.2 or less. Machinists were the only occupation with a statistically significant raised odds ratio (2.5, 1.2-5.2). Adjusted for tobacco, the odds rose about 1.5-fold (interval 1.3-1.8) per step on an index of drinking in the year before admission. The authors concluded that asbestos and nickel were not found to be risk factors. They noted fewer people took part than expected, reducing the study's power.

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: Hospital-based matched case-control study using personal interviews, analyzed with a conditional logistic model
• Who was studied: White men in the New Haven, Connecticut, area: 92 cases of laryngeal carcinoma diagnosed 1975-1980 and 181 matched hospital (general surgery) controls. All were alive at the time of the study (1980-1981). Controls were matched on county of residence or residence within a 25-mile (40.2-km) radius of the case's address.
• Exposure: Self-reported lifetime occupations, industries and physical/chemical exposures, including asbestos (fiber type not specified), nickel and other metals. 'Ever' exposure was defined as at least 20 hours per week for at least six months.
• Main results:
  • Self-reported asbestos exposure was reported by 10.9 per cent of cases and 13.3 per cent of controls. The odds ratio was 0.8 (95 per cent CI 0.4-1.7), adjusted for tobacco and alcohol.
  • Occupations the authors called asbestos handlers had odds ratios of 1.2 or less: brake repairmen 1.2 (0.3-4.6), asbestos workers 1.1 (0.4-2.9) and plumbers 0.9 (0.3-2.8).
  • Machinists were the only occupation with a statistically significant odds ratio: 2.5 (95 per cent CI 1.2-5.2), adjusted for tobacco and alcohol.
  • Among machinists, duration of employment was significantly related to the disease in a trend test (p less than 0.01).
  • None of the industries studied had a 95 per cent confidence interval excluding one.
  • Nickel exposure was reported by 15.2 per cent of cases and 11.6 per cent of controls. The odds ratio was 1.3 (95 per cent CI 0.7-2.7).
  • Beryllium exposure had an odds ratio of 4.8 (95 per cent CI 0.9-24.4), based on a small number of exposed men.
  • Alcohol was measured on a four-level index (none to high) of total consumption in the year before hospital admission. The odds ratio was 1.51 per category (95 per cent CI 1.3-1.8), adjusted for lifetime tobacco dose, based on 87 cases and 153 controls.
• The authors' conclusion: The authors concluded that asbestos and nickel were not found to be risk factors for laryngeal carcinoma in this study. They also concluded that the amount of tobacco smoked and alcohol consumed were positively associated with risk.
• Limitations the authors state:
  • Fewer cases and controls agreed to take part than expected, which reduced the study's power. The study was designed to detect odds ratios of about three.
  • Interviewed cases were somewhat younger than all incident cases and more likely to have early-stage tumors.
  • Errors in recall of exposures probably occurred.
  • Small numbers of persons exposed to specific factors weakened the analysis.
  • The sample size was too small to test risk factors by tumor site within the larynx.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Throat and laryngeal cancer.

Medical terms in this study, explained in our Lexicon: Carcinoma, Case-Control Study, Odds Ratio, confidence interval, Laryngeal Cancer.

Related studies

• A case-control study of occupational risk factors for laryngeal cancer — P. Wortley, T.L. Vaughan, et al. (1992)
• Occupational asbestos exposure as a risk factor for laryngeal carcinoma in a population-based case-control study from Germany — H. Ramroth, W. Ahrens, et al. (2011)
• Exposure to cement dust, related occupational groups and laryngeal cancer risk: results of a population based case-control study — A. Dietz, H. Ramroth, et al. (2004)
• Occupation and the risk of laryngeal cancer in Uruguay — E. De Stefani, P. Boffetta, et al. (1998)
• Diet and other risk factors for laryngeal cancer in Shanghai, China — W. Zheng, W.J. Blot, et al. (1992)
• Occupational Risk Factors for Laryngeal Cancer in Tunisia: A Case Control Study — A. Gaddour, A. Brahem, et al. (2023)

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