Historical cohort study

Zammit S, Allebeck P, Andreasson S, Lundberg I and Lewis G (2002). Self reported cannabis use as a risk factor for schizophrenia in Swedish conscripts of 1969 Historical cohort study. British Medical Journal, 325, 1199-1201. 

A few studies have reported an association between bladder and renal cancers and occupations having the potential for exposures to asphalt. In an historical cohort study of 1320 workers in the asphalt industry, there was a significant increase in brain cancer [standardized mortality ratio (SMR) 500] but not in respiratory, bladder, or gastrointestinal cancer. Of 679 Danish men who were heavily exposed to asphalt, significant increases occurred in the incidences of cancer of the mouth (SMR 1111), esophagus (698), rectum (318), and lung (344). ... 

Mundt KA, Dell LD, Austin RP, et al Historical cohort study of 10,109 men in the North American vinyl chloride industry, 1942-72 Update of cancer mortality to 31 December 1995. Occup Environ Med 57(11) 774-81, 2000... 

In a historical cohort study, changes in renal function in 86 patients taking lithium were evaluated first after a median treatment duration of 5.8 years and again after 16 years (367). Maximum plasma osmolality was reduced in nine of 63 patients in the initial study and in 24 of 63 at follow-up. Other findings included increased serum... 

Bendz H, Aurell M, Lanke J. A historical cohort study of kidney damage in long-term lithium patients continued surveillance needed. Eur Psychiatry 2001 16(4) 199-206. 

Tsuda, T., Bahazono, A., Yamamoto, E., Kurumatani, N., Mino, Y., Ogawa, T., Kishi, Y., Aoyama, H. (1995). Ingested arsenic and internal cancer, a historical cohort study followed for 33 years. Am. J. Epidemiol. 141 198-209. 

Historical Cohort Study When the need arises to study the health status of a group of individuals, there is often a large body of historical data that can be utilized. If sufficient information exists on individuals exposed in the past to a potential workplace hazard, then it may be possible to undertake a retrospective cohort study. The historical data will have been collected for reasons that have nothing to do with epidemiology. Nevertheless, the availability of personnel records, such as registers of new and former employees, payrolls, work rosters, and individuals career records, has enabled many epidemiological studies to be conducted, in particular, mortality studies. 

The principles of a historical cohort study can also be applied to follow a cohort of workers prospectively. This approach will be discussed further in the next section, although it should be emphasized that many historical data studies have a prospective element in so far as they are updated after a further period of follow-up. The discussion of historical cohort studies in this section will concentrate on mortality and cancer incidence studies. However, there is no reason why hearing loss, lung function, or almost any measure of the health status of an individual should not be studied retrospectively if sufficient information is available. 

The principles of historical cohort studies are described in the following subsections. 

Prospective Cohort Study Prospective cohort studies are no different in principle from historical cohort studies in terms of scientific logic, the major differences being timing and methodology. The study starts with a group of apparently healthy individuals whose health and exposure are studied over a period of time. As it is possible to define in advance the information that is to be collected, prospective studies are theoretically more reliable than retrospective studies. However, long periods of observation may be required to obtain results. 

Swan SH, Beaumont JJ, Hammond SK, et al. Historical cohort study of spontaneous abortion among fabrication workers in the Semiconductor Health Study Agent level analysis. AmJIndMed 1995 28(6) 751-69. 

Measles Infection. In a historical cohort study in Guinea-Bissau, measles infection was associated with a large reduction in the risk of skin test positivity to house dust mites, compared with children who had been vaccinated against measles and not acquired the infection [ 102(111C)]. The mechanism of this effect is difficult to fit into the hygiene hypothesis because measles causes sequential Thl and Th2 cytokine responses. Measles vaccination leads to an enhanced Th2-like effect, with suppression of delayed-type hypersensitivity reactions [159(NC)]. 

Prospective cohort studies can provide strong evidence of associations between drugs and diseases because the exposure is assessed before the outcome occurs. However, because many cohort studies require large numbers of people followed for long periods of time, they can be expensive and, in some instances, infeasible. Retrospective or historical cohort studies can overcome these limitations if high-quality data have been collected already. 

Although randomized, controlled trials form the basis for some of the most reliable assessments of drug safety, pregnant women usually are not eligible for participation in clinical trials. Other types of data often are used to estimate the risk associated with medication use during pregnancy, such as animal studies, case reports, case-control studies, prospective cohort studies, historical cohort studies, and voluntary reporting systems. 

An epidemiological study in which a defined group of persons known to be exposed to a potential disease risk factor is followed over time and compared to a group of persons who were not known to be exposed to the potential risk factor to evaluate the differenees in rates of the outcome. Also termed a prospective study, followup study, incidence study, retrospective cohort, or historical cohort study. 

Marks GB, Ng K, Zhou J et al 2003 The effect of neonatal BCG vaccination on atopy and asthma at age 7 to 14 years an historical cohort study in a community with a very low prevalence of tuberculosis infection and a high prevalence of atopic disease.) Allergy Clin Immunol 111 541-549... 

T Tsuda, T Ogawa, A Babazono, H Hamada, S Kanazawa, Y Mino, H Aoyama, E Yamamoto, N Kurumatani. Historical cohort studies in three arsenic poisoning areas in Japan. Appl Organometal Chem 6 333-341, 1992. 

Overview. The UMASS team conducted an historical cohort study of all employees of the Digital Equipment Corporation semiconductor manufacturing plant in Hudson, Massachusetts. Current employees were interviewed by trained female interviewers that were blind to the h5q)othesis... 

Following the announcement of the results of the UMASS-Digital Equipment Corporation study, IBM requested JHU to perform two epidemiological studies at IBM semiconductor plants. The request was for an historical cohort study and a prospective study. The objectives of the studies were to determine if. . there was an excess of adverse reproductive health effects among clean room employees, compared with employees working in other manufacturing areas or non-manufacturing environments and to determine whether any specific processes or chemicals were associated with adverse reproductive health outeomes. With this two-study approach, JHU was able to assess both current and past risks. 

Historical Cohort Study. Overview. The historical cohort study covered the period from 1980-1990, the prospective study covered the period from June 1989-September 1991. For a married male or female to be eligible for inclusion in the historical cohort study, he or she must have been between 20 and 44 years of age, have worked at IBM for at least 6 months, and not have imdergone surgical sterilization prior to 1980. Wives of the male employees were included in the study. In addition, a sample of women volimtarily terminated from IBM was included. Detailed work histories... 

Chodick G, Heymann AD, Hash S, Kokia E, Shalev V. Persistence with stafins and incident cataract a population-based historical cohort study. Ann Epidemiol 2010 20 136--42. 

Carmeli Y, Samore MH. Comparison of treatment with imipenem vs. ceftazidime as a predisposing factor for nosocomial acquisition of Stenotrophomonas maltophilia a historical cohort study. Clin Infect Dis 1997 24 1131-1134. Papadakis KA, Vartivarian SE, Anaissie EJ, Samonis G. Xanthomonas maltophilia bacteremia in cancer patients an analysis of 44 episodes. Clin Infect Dis 1994 19 558. 

K. Zarchi, A. Akbar and K. H. Naieni, Long-term pulmonary complications in combatants exposed to mustard gas a historical cohort study, Int.J. Epidemiol, 2004,33, 579-581. 

M. Ghanei, M. Rajaee, S. Khateri, F. Alaeddini and D. Haines, Assessment of fertility among mustard-exposed residents of Sardasht, Iran a historical cohort study, Reprod. Toxicol, 2004,18, 635-639. 

Levy PS, Roth HD, Hwang PM, Powers TE (2002) Beryllium and lung cancer a reanalysis of a NIOSH cohort mortality study. Inhal Toxicol 14 1003-1015 Love RG, Miller BG (1982) Longitudinal study of lung function in coal miners. Thorax 37 193-197 Marsh GA, Youk AO, Stone RA, Buchanich JM, Gula MJ, Smith TJ, Quinn MM (2001a) Historical cohort study of US man-... 

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