A Cohort Study Of Smoking And Bladder Cancer Was Conducted
A Cohort Study Of Smoking And Bladder Cancer Was Conducted
Construct a two-by-two table based on the provided data, identify the appropriate measure of relative risk, provide its formula, calculate this measure using the data, and interpret the result in a concise sentence.
Paper For Above instruction
The investigation into the association between smoking and bladder cancer within a small island population necessitates an organized analysis of epidemiological data. The initial step involves creating a 2x2 contingency table based on the provided information. The total population on the island was 1,000 individuals, with 400 identified as smokers and 600 as non-smokers. Among smokers, 50 developed bladder cancer, while 10 non-smokers also developed the disease. The table is structured as follows:
| Bladder Cancer | No Bladder Cancer | Total | |
|---|---|---|---|
| Smokers | 50 | 350 | 400 |
| Non-smokers | 10 | 590 | 600 |
| Total | 60 | 940 | 1000 |
To quantify the effect of smoking on the risk of developing bladder cancer, the measure of choice is the relative risk (RR). The relative risk compares the probability of disease among the exposed group (smokers) to that among the unexposed group (non-smokers). The formula for relative risk is:
RR = (a / (a + b)) / (c / (c + d))
Where:
- a = number of exposed individuals with the disease (50)
- b = number of exposed individuals without the disease (350)
- c = number of unexposed individuals with the disease (10)
- d = number of unexposed individuals without the disease (590)
Calculating the individual probabilities:
Risk among smokers: 50 / 400 = 0.125
Risk among non-smokers: 10 / 600 ≈ 0.0167
Thus, the relative risk (RR) is:
RR = 0.125 / 0.0167 ≈ 7.48
This indicates that smokers are approximately 7.5 times more likely to develop bladder cancer than non-smokers in this population.
In conclusion, the calculated relative risk demonstrates a strong association between smoking and increased risk of bladder cancer, suggesting that smoking significantly elevates the likelihood of developing this cancer within the studied population.
References
- Bonita, R., Beaglehole, R., & Kjellström, T. (2006). Basic Epidemiology (2nd ed.). World Health Organization.
- Cornfield, J. (1951). Notes on the design and analysis of epidemiologic studies. American Journal of Public Health, 41(9), 1075–1076.
- Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins.
- Viera, A. J., & Bangdiwala, S. I. (2007). Eliminating bias in randomized controlled trials: importance of allocation concealment and masking. Family Medicine, 39(2), 132–137.
- Wacholder, S., Silverman, D. T., & McLaughlin, J. K. (1992). Selection of controls in case-control studies. Journal of the National Cancer Institute, 84(12), 1055–1058.
- World Health Organization. (2013). Global status report on noncommunicable diseases 2014.
- Greenland, S. (2003). Variables within variables: Simple techniques for exploring heterogeneity. Journal of Clinical Epidemiology, 56(11), 1031–1037.
- Hennekens, C. H., & Buring, J. E. (1987). Epidemiology in Medicine. Little, Brown.
- Schlesselman, J. J. (1982). Case-Control Studies: Design, Conduct, Analysis. Oxford University Press.
- Kelsey, J. L., Whittemore, A. S., Evans, A. S., & Thompson, W. D. (1996). Methods in Observational Epidemiology. Oxford University Press.