The initial design attempted to contact all men aged 45 to 59 years from the town of Caerphilly and adjoining villages.  2512 subjects (response rate 89%) identified from the electoral register and general practice lists were examined between July 1979 until September 1983 (phase I).

Men were initially seen at an evening clinic, where they completed a questionnaire, had anthropometric measures and an ECG taken. They also completed a food frequency questionnaire at home (Fehily et al 1994). They subsequently re-attended an early morning clinic to have fasting blood samples for a wide variety of tests.

Quality control was examined by the use of both "blind" split samples as well as a second repeat measure on a random sub-sample to examine intra-individual variation.

Phase I variables

Phase II was undertaken between July 1984 to June 1988. An additional 447 new men were included who had moved into the study areas. In addition to the tests undertaken at phase I, new tests included audiometry.

Phase II variables

Phase III was undertaken between November 1989 to September 1993. It followed the same methods as before. The main new features were a standardised battery of cognitive function tests as well as a variety of new platelet and bleeding time tests.

Phase III variables

Phase IV, the last time the men were examined, was undertaken between October 1993 to February 1997. Audiometry measured at phase II was repeated as was cognitive function measured at phase III.

All men have been followed up for incident IHD through mortality flagging, self-reported information confirmed by medical records, positive history to the Rose angina questionnaire, checking hospital admissions and new evidence of ECG ischaemia. The WHO criteria were used to define cases of non-fatal myocardial infarction.

At each phase, 40-50 mls of blood were taken and stored at either -40 or -80 C. This insightful decision has enabled subsequent researchers to rapidly test new hypotheses (e.g. the role of H. Pylori, cytomegalovirus and C. Pneumoniae with respect to IHD risk: see Strachan et al 1999, 1999, 1998).

A large amount and variety of samples (serum, plasma, sodium citrate, etc.) remain for future potential analyses. Unfortunately, no whole blood was stored from phase I.

Phase IV variables

Phase V was undertaken between August 2002 and June 2004. This repeated questionnaire data but also had a special memory clinic to assess men who scored poorly on the cognitive assessments to see if they may have any cognitive impairment or dementia.

Phase VI involved a postal questionnaire to obtain new data on the Warwick-Edinburgh Mental Wellbeing Scale.

Phase VII involved a final repeat assessment of cognition and activities of daily living with a clinical opinion as to whether their diagnosis from “normal”, “MCI”, “dementia” required revision or not.

Between 1936 and 1942 Philip D ;Arcy Hart co-ordinated, on behalf of the MRC,a series of surveys of chronic pulmonary disease in South Wales coal miners to address the growing concerns about the respiratory health of miners.[1]

To investigate further the causes of lung disease in miners the MRC established the MRC Pneumoconiosis Research Unit at Llandough Hospital in 1945.[2]

In 1948 Dr Archie Cochrane joined the unit and established a team carrying out what he called 'clinical and environmental studies'. During the 1950s this team was largely concerned with epidemiological studies of respiratory disease in miners. They did, however, carry out electro-cardiographic surveys and studies of blood pressure at the behest of Dr Bill Miall.

In 1960 Cochrane became the David Davies Professor of Tuberculosis and Chest Diseases at the Welsh National School of Medicine and the MRC agreed toseparate his team to create an MRC Epidemiology Unit in South Wales.[3] In 1974 on the retirement of Cochrane, Dr Peter Elwood took over until his own retirement in 1995, at which point a decision was made to close the Unit.

Mr Peter Sweetnam took running the Unit until the end of March 1999 when the Unit closed. In addition to work on mining communities, the Unit carried out studies of other industrial workers, iron deficiency anaemia, migraine, eye disease, aspirin, environmental lead, milk supplementation, and cardiovascular disease.

Perhaps the most influential study the Unit carried out was the randomised-controlled trial of aspirin, which showed for the first time that daily aspirin might reduce mortality following myocardial infarction.[4] The paper describing the results of this study was among the fifty most cited papers published in the British Medical Journal.[5]

References

1. D’Arcy Hart P with Tansey EM. Chronic pulmonary disease in South Wales coal mines: an eye-witness account of the MRC surveys (1937-1942) Social History of Medicine 1998; 11: 459-468.
2. Perspectives on the role of the MRC Eds: Austoker J, Bryder L.. Oxford: Oxford University Press, 1989 pp. 137-161.
3. Cochrane AL, with Blythe M. One Man’s Medicine British Medical Journal: London 1989.
4. Elwood PC, Cochrane AL, Burr ML, Sweetnam PM, Williams G, Welsby E, Hughes SJ, Renton R. A randomised controlled trial of acetyl salicylic acid in the secondary prevention of mortality from myocardial infarction. BMJ 1974; i: 436-440.
5. Dixon B. The 'top 50'; a perspective on the BMJ drawn from the Science Citation Index. BMJ 1990; 301: 747-751.