The Seven Countries Study: U.S.A.

Why The Railroad Study?

The study of U.S. railroad men was the “baby” of Henry Longstreet Taylor. He had the idea to compare coronary heart disease rates among rail occupations to get at the role of habitual physical activity. Taylor realized that there would likely never be a “definitive experiment,” due to feasibility and cost, in which physical activity would be modified and the effect on heart attack rates measured.

The U.S. Railway Workers Study was originally designed to be independent from the Seven Countries Study and to make only internal comparisons among rail occupations having different levels of habitual physical activity. It was only later incorporated by Keys and Taylor into Seven Countries analyses to provide representation of the homogeneously high-fat, high-saturated-fat eating pattern of North America. It was not a part of the initial Keys’ hypotheses about differences in coronary disease rates according to habitual diet among contrasting, stable, rural populations.

Lewis Thomas once defined epidemiology as “thumbing through death certificates,” an insensitive and incomplete depiction, at best. But it was such a “thumbing,” done early on and systematically, that revealed to Henry Taylor and those of us who had become his colleagues, that coronary heart disease death rate differences among classes of rail workers were in the direction of the hypothesis that physical activity causes lower rates. Taylor was also the first to criticize his own brainchild, pointing out problems of misclassification of physical activity in the Railroad Retirement Board list of occupations, and of selection bias, which might tend to concentrate workers who were ill, or who were becoming ill, among the less active railroad professions.

This refreshingly candid criticism of one’s own offspring is rarely found in science today. Taylor’s basic integrity was accompanied by a skeptical and dispassionate “Old School Physiology,” which put him in good stead for epidemiological pursuits. So it was that the novel idea was proposed to the National Institutes of Health to examine the active and less active rail workers at their work sites, measuring coronary disease incidence in the railway cohort while accounting for measured confounders and coexisting morbidity. To his surprise, and certainly to the surprise of some of his Minnesota colleagues, the proposal was approved by peer review in the National Heart Institute. Thus began the U.S. Railway Workers Study.

Fall, 1957 – Riding the Rails

The Railroad Study operation was “first class” from the beginning, and I was happy to be involved. I had a few pangs of regret when I was unable to accompany Ancel Keys in the fall of 1957 to conduct pilot surveys in Finland, Crete, and Southern Italy, but my services were needed to get the Railroad Study on track. This we did, with procedures, forms, and the beginnings of cardiovascular disease classifications that would eventually become The Minnesota Code and the WHO book: Cardiovascular Survey Methods.

In those exciting early days, I particularly enjoyed working with Taylor to design a unique traveling laboratory. He proved extremely skillful in face-to-face negotiations with railway managers and union brotherhoods, obtaining, among other things, the long-term loan of a Pullman car for the study. With the new National Heart Institute grant, he proceeded to have that car renovated in the old Great Northern maintenance yards off Como Avenue in St. Paul, where we spent countless hours supervising and kibitzing. The laboratory car was well laid out, with a reception area; a series of examining rooms for anthropometric measurements, medical history, physical exam, and blood pressure; and a large work area for the resting and exercise electrocardiogram. Toward the end, there was a booth for the chest x-ray and then a wet lab area for blood and urine sample processing.

After a trial run in the old St. Paul Depot, we moved out on the rails, hooking up to the power, water, and steam in stations or rail yards across the line, northwest to the cities of Spokane, Pasco, Seattle, then down to Portland and San Francisco, and back again.

Taylor had carefully negotiated two essential elements for the success of the study: Clerks could be examined at their work site during working hours without their pay being docked, and, at my insistence, information we collected on all employees would be held confidential and not provided to railway physicians or companies. These guarantees clinched the enlistment of the rail brotherhoods. The first-round survey involved comparing the risk factors and medical findings of rail executives and clerks with switchmen and right-of-way personnel, among whom Taylor’s pilot work had validated different levels of habitual activity and on-the-job oxygen consumption.

The rail men were a jovial bunch, and our crew, too, was congenial, working together effectively and examining up to forty men a day. Our team developed in this first-round survey many of the field strategies that became trademarks of Minnesota population studies over the years: careful planning and pre-negotiations; field testing and pilot studies; clear definition of the population with a census; intensive recruitment; thoughtful scheduling; and central data-editing, processing, and analysis. In our working and traveling together, we also elaborated – by plan and by trial and error – much of the general field procedure that the Laboratory of Physiological Hygiene, and then the Division of Epidemiology, utilized in subsequent operations.

We learned, for example, that staff, after six straight days of work, needs a break in order to remain effective. And after three weeks straight, they need a brief home leave. We also found it impossible to use a converted 1895 Rock Island Line presidential sleeping car as a dormitory. So we were housed in quiet motels and ate dinner in attractive restaurants. This helped relieve the heavy work routine and maintain morale over the long haul. We also learned to avoid over-booking, particularly the first day at a new location.

There were many delightful adventures “on the rails,” both intellectual and social. As we traversed the land, we on the team held long conversations about the colorful rail men we met, and about the burgeoning new field in which we were involved – cardiovascular disease epidemiology. On the second round of exams, starting in 1962, I had my soprano saxophone along. I’d serenade the countryside from the rear of the lab car, which usually served as the caboose for the train to which we were attached. We acquired many friends along the line as we made contacts to hire and train short-term medical examiners. Several Twin Cities colleagues, Robert Rothenberg, Dennis Kane, James Dahl, “Mack” Richards, and William Moore, participated in two survey rounds over six years, ’57-’58 and ’62-’63. We were joined by a series of overseas visitors who came to train at the new “epidemiological Mecca” at the University of Minnesota, Stadium Gate 27.

The staffing was quite exceptional as we began the first-round survey, with such Minnesota experts as Francisco (Paco) Grande helping with the initial dietary interviews, and Joseph (Jaschka) Brozek doing the anthropometric measurements. I, along with technicians Walt Carlson and John Vilandre, and later, biophysicist Pentti Rautaharju, carried out the exercise electrocardiographic monitoring. Nedra Foster and Gail Dolliff handled the blood, urine, and x-ray technical duties, while I conducted the clinical exams, along with drop-in colleagues. In all it was a happy, disciplined, and effective operation.

We chose to study U.S. Railroad employees because they were largely stable in their specific occupations and in their lifetime employment, and had measured differences in the physical activity required at work. Moreover, all rail employees are covered by a pension plan, which maintains detailed employee records of employment, disability, retirement, and death. Permission was required of the rail companies, of the Railroad Retirement Board, and of the various labor unions involved, including each local railroad brotherhood official. All twenty rail companies that operated in the northwestern quadrant of the United States – circumscribed by Chicago, St. Louis, San Francisco, and the Canadian border – were involved. Selection of thirty sampling units ensured proportional representation in each geographical area and each size of urban area. Our staff, usually Taylor or me, recruited and scheduled participants at union meetings. The laboratory car visited each location at least twice during each survey round. Unfortunately, I kept no written or photographic record of the details of these railroad expeditions.