Long Term Cohort Studies – The Shanghai Cohort Study
Thinking long-term. It’s not necessarily a strength of lawyers or their clients. For scientists, however, it’s often a priority. Thus, the world of science today includes an ever-increasing number of ongoing, long-term studies aimed at understanding why people contract diseases and looking for markers of disease. And, of special note, some of the studies include regular sampling of fluids and tissues of members of the study. The researchers may not know what they are looking for, but they do know it’s important to gather and analyze data.
For a concrete example, consider the Shanghai Cohort Study, and this new paper on PAHs found as a result of periodic sampling and analysis of the urine of non-smokers . Carcinogenesis (2013) doi: 10.1093/carcin/bgt352 First published online: October 22, 2013.
The following is just a partial list of outputs from the study; the list is taken from this page at NCI:
"Shanghai Cohort Study
Lead Contact and/or Principal Investigator (PI):
Jian-Min Yuan, M.D., M.P.H., Ph.D.
University of Pittsburgh Cancer Institute
Funded Since: 1987
Funding Source: NCI Extramural Program (Epidemiology and Genomics Research Program, Division of Cancer Control and Population Sciences; CA144034External Web Site Policy)
Year(s) of Enrollment: 1986-1989
The Shanghai Cohort Study consists of 18,244 men in Shanghai, China, assembled during 1986-1989 when subjects were between the ages of 45 and 64 years. At recruitment, all cohort members provided detailed dietary and medical histories as well as blood and urine specimens. In the follow-up of 2000-2001, buccal cells were collected from 13,815 original cohort participants (92% of all surviving cohort members).
The cohort has been followed for the occurrence of cancer, death, and major health outcomes (e.g., cardiovascular disease, diabetes) through routine ascertainment of new cases from the population-based Shanghai Cancer Registry and Shanghai Vital Statistics Units, and annual visits to all known surviving cohort members. In addition to cohort analyses to examine the impact of cigarette smoking, alcohol intake, and certain dietary factors on mortality and morbidity, a series of nested case-control studies has been conducted to further elucidate the role o diet-related factors using biomarkers as more specific and objective measures for exposure in the etiology of cancer. Furthermore, the interplay of genetic and dietary factors in influencing cancer risk has been examined among the cohort participants.
This prospective cohort study has contributed a wealth of knowledge on the role of diet-related and other environmental exposures, as well as genetic factors in the etiology of cancer. More than 35 peer-reviewed articles have emanated from this study. Significant scientific contributions include the:
first direct evidence that aflatoxin is a human hepatocarcinogen, and the evidence of a strong synergistic effect of urinary aflatoxin biomarkers and chronic infection with hepatitis B virus on liver cancer risk (Lancet.External Web Site Policy 1992 Apr 18;339(8799):943-6; Cancer Epidemiol Biomarkers Prev.External Web Site Policy 1994 Jan-Feb;3(1):3-10);
first evidence that circulating testosterone levels predict liver cancer risk but only among carriers of hepatitis B virus (Int J Cancer.External Web Site Policy 1995 Nov 15;63(4):491-3);
first evidence in a non-Occidental population that smoking is a strong predictor of overall mortality and cancer mortality (JAMA.External Web Site Policy 1996 Jun 5;275(21):1646-50)." (emphasis added).