Faculty Nan Laird and Christoph Lange invent new statistical tools for gene analysis.

Photo Credit: Kent Dayton

Vital Statistics

Traditionally, public health measures the distribution of a problem, defines the causes, and designs and implements interventions. Every step of this process relies on reliable numbers generated by epidemiology—the study of factors affecting the health and illness of populations. Since its founding, the School has made a priority of teaching and research into the methods of epidemiology, analyzed data on epidemic and endemic disease, and evaluated control methods.

When infectious causes of death and disease gave way to chronic conditions, the School built the premier chronic disease epidemiology department in the nation. It introduced the idea of the “web of causation,” a model in which each component generates myriad effects. The School’s groundbreaking research uncovered the link between breast cancer risk and reproductive experience. In 1981, School epidemiologists Dimitrios Trichopoulos and Brian MacMahon were the first to demonstrate the health threat from exposure to second-hand cigarette smoke. And the School’s 1996 “Global Burden of Disease” report was the first attempt to develop a comprehensive set of estimates for patterns of mortality and disability for 107 chronic and infectious diseases, from AIDS to heart disease to depression.

The School has also made signal contributions to the field of biostatistics—the theory and application of statistical science to public health problems and biomedical research. The School provided the biostatistical design for the first study showing a connection between DES, ­ a drug used to prevent miscarriages, ­ and vaginal cancers, miscarriages, and infertility in a mother’s female offspring. Beginning in the 1980s, the School built large biostatistics laboratories capable of administering and keeping tabs on hundreds of clinical trials at once. The labs played a key role in the development of cancer treatments. And the Center for Biostatistics in AIDS Research, established in 1995, became the nation’s leading facility for assessing antiviral therapies for HIV infection, analyzing treatments for common opportunistic infections and bringing innovations to the design and coordination of AIDS clinical trials.

Today, Harvard Chan School is investing in its Bioinformatics Core and Program on Quantitative Genomics to pave the way for more effective prevention and intervention. The School’s infectious disease epidemiologists have been intimately involved in identifying and tracking global emerging infections of the 21st century. As the new millennium unfolds, they have made crucial discoveries in the genetics of extensively drug-resistant TB, in the transmission patterns of SARS, and in the spread and virulence of the 2009 H1N1 influenza virus.

School scientists have also developed improved treatment protocols to reduce hospital selection for drug-resistant bacteria. Its biostatisticians have discovered how to analyze massive quantities of genetic data, speeding the quest for the genetic basis of asthma, diabetes, and other disorders.

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