Cell phone research ably explains nuances of study design.

The New York Times article "Do cell phones cause brain cancer?" takes on the complex issue of examining if cell phone use increases the risk of brain cancer.  While telling the tale, physician and Pulitzer Prize-winning author Siddartha Mukherjee provides an informative and well-written narrative on the nuances of biomedical studies, with specific attention to epidemiology studies.

Epidemiology studies are important tools that help researchers study relationships between environmental exposures and adverse human health outcomes. But, as Mukherjee points out, they are just one piece of the puzzle.  Animal and in vitro studies are also important tools. 

Mukherjee does such a fantastic job of providing a brief history of research on health issues associated with cell phones, smoking and occupational hazards that you don't realize you are learning the basics of epidemiology, including approaches and bias of different research study designs. His explanation of case-control studies and their associated limitations is especially good.

The article tackles the important issue of biases in studies.  Bias can increase the amount of noise in data and sometimes give the wrong answer. Mukherjee provides a fair perspective on potential biases in environmental epidemiology studies. 

Researchers often employ the randomized trial to reduce bias in studies by randomly assigning participants to receive treatment or no treatment. Dr. Mukherjee makes the important observation that environmental epidemiologists cannot employ the randomized trial since it is unethical to expose people to potentially cancer causing substances.

Effect size was one issue that was neglected in this otherwise excellent article. Environmental exposures that have strong effects are easier for researchers to find. For example, persons who have ever smoked in their lives are 10 to 15 times as likely to be diagnosed with small cell lung cancer or squamous cell lung cancer compared to lifetime non-smokers. Based on studies of cell phones and brain cancer to date, much smaller effects would be expected. Thus, if cell phones truly cause cancer, studies will need large numbers of participants to precisely estimate the risk of cancer associated with their use.

This article provides a balanced update to the current debate on cell phone use and brain cancer, while informing the reader on the nuances of epidemiological study design. This article is recommended to anyone wishing to learn more about either of these topics.

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