Document pmzDj979x7b4NorNrn2BLK1Vd

368 INDUSTRIAL HYGIENE AND OCCUPATIONAL MEDICINE which contains long term observations on a group of industrial employees who had suffered myocardial infarction. That article also contains a number of pertinent references, mainly limited to follow-up studies in cases of coronary occlusion. Another possible way of correlating occupational and cardiac histories is through the use of records in cardiac clinics. This method provides detailed and generally reliable medical information, but unless a special effort is made, may leave much to be desired in regard to the occupational histories. The present study is based on the use of clinic records supplemented by personal interviews with all the patients concerned. In the interviews an attempt was made to fill in any gaps in the occupa tional histories. The principal shortcoming of this method lies in the fact that it limits the study to those patients who survived and who continued to attend clinic regularly during the period of the study. One of the purposes of this report is to call attention to deficiencies in the information which is at present available, in the hope that the future will produce more valuable data. Any effort to determine the effect of employment on the course of heart disease obviously calls for a period of observation of many years. An ideal study would Table 1.--Work History of 580 Patients Attending Bellevue and Lenox Hill Cardiac Clinics in 1949, in Relation to Duration of Heart Disease Years Heart Disease Had Been Known Under 5................................................... 5-9............................................................ 10-14............................................... ......... 15 and over............................................ Total................................................ Patients Who Had Worked No. % 203 73 89 79 83 89 94 97 469 81 Patients Who Had Never Worked A No. %. 75 ' 27 23 21 10 11 33 111 19 Total No, % 278 100 112 100 93 100 97 100 580 100 be one in which groups of several hundred persons of each sex, with similar age distribution and similar cardiac lesions, could be divided at random into two series, one to be employed and the other not. Life table studies might then reveal whether employment has had a deleterious or a beneficial effect. Episodes of cardiac failure or progression of the disease could also be compared. In the absence of such ideal experimental conditions it is still possible to obtain a certain amount of useful data from records that are riiore or less readily available, as has been done in the present . study. COMPOSITION OF THE GROUP STUDIED The cases the records of which were studied comprised the active case load of the. adult cardiac clinics at Bellevue and Lenox Hill Hospitals, in New -York during the year 1949, representing 580 .patients. The composition of the group and the occupational status of its members in 1949 have been described previously in detail.lb In regard-to...the age and sex distribution as well as the types of heart disease, the group may be said to be fairly representative in that it includes males and females in approximately equal numbers, representatives of all age groups in substantial numbers, and all types and degrees of heart disease. . The length of time during which patients were known to have had heart disease at the clinic is shown in table 1. In slightly less than one half of them heart disease was known to have been present for less than five years, while in approximately