[Tuberculosis in Iceland. 1976].

Because of signs of tuberculous lesions in old skeletons it can be stated with certainty that tuberculosis has occurred in the country shortly after the settlement. From that time and up to the seventeenth century, little or nothing is known about the occurrence of the disease. A few preserved descriptions of diseases and deaths indicate that tuberculosis has existed in the country before the advent of qualified physicians in 1760. On the basis of papers and reports from the first physicians and the first tuberculosis registers the opinions is set forth that the disease has been rare up to the latter part of the nineteenth century. During the two last decades of that century the disease began to spread more rapidly and increased steadily up to the turn of the century. Although reporting of the disease was started in the last decade of the nineteenth century the reporting was first ordered by law with the passage of the first tuberculosis Act in the year 1903. With this legislation official measures for tuberculosis control work really started in the country. The first sanatorium was built in 1910. In 1921 the tuberculosis Act was revised and since then practically all the expenses for the hospitalization and treatment of tuberculous cases has been defrayed by the state. In the year 1935 organized tuberculosis control work was begun and a special physician appointed to direct it. From then on systematic surveys were made, partly in health centers i.e. tuberculosis clinics, which were established in the main towns, and partly by means of transportable X ray units in outlying rural areas of the country. In 1939 the tuberculosis Act was again revised with special reference to the surveys and the activities of the tuberculosis clinics. This act is still in force. Some items of it are described. The procedure of the surveys and the methods of examination are described. The great majority of subjects were tuberculin tested and all positive reactors X rayed. Furthermore, X ray examination was made in all cases where tuberculin examination had not been made or was incomplete. The negative reactors were not X rayed. The tuberculin tests were percutaneous, cutaneous and intracutaneous. The X ray examination during the first years was performed by means of fluoroscopy and roentgenograms were made in all doubtful cases. In 1945 when the survey of the capital city of Reykjavík was made and comprised a total of 43,595 persons photoroentgenograms were made. After 1948 only this method together with tuberculin testing was used in all the larger towns in the country. During the period 1940-1945 such surveys were carried out in 12 medical districts, or parts thereof and included 58,837 persons or 47 percent of the entire population. The attendance in these surveys ranged from 89.3 percent to 100 percent of those considered able to attend. In the capital city, Reykjavík, the attendance was 99.32 percent. The course and prevalence of tuberculosis in Iceland from 1911 to 1970 are traced on the basis of tuberculosis reporting registers, mortality records which were ordered by law in 1911, tuberculin surveys and post mortem examinations. The deficiencies of these sources are pointed out. Since 1939 the morbidity rates are accurate. The number of reported cases of tuberculosis increases steadily up to the year 1935, when 1.6 percent of the population is reported to have active tuberculosis at the end of that year. Thereafter it begins to decline gradually the first years but abruptly in 1939, then without doubt because of the revision of the tuberculosis legislation and more exact reporting regulations. After that year the fall is almost constant with rather small fluctuations as regards new cases, relapses and total number of reported cases remaining on register at the end of each year. In 1950 the new cases are down to 1.6 per thousand and at the end of the year the rate for those remaining on register is 6.9 per thousand. In the year 1954 there is a noteworthy drop both in new cases and the total number reported, doubtless because of the new specific medication which began in 1952. In 1960 the new cases are down to 0.4, relapses 0.2 and the rate for those remaining on register at the end of the year 2.4 per thousand. And in 1970 the rate for the same categories are: new 0.2, relapses 0.06, and remaining at the end of the year 0.5 per thousand. At the beginning of the period, when registration of deaths was initiated, tuberculosis mortality was found to be about 150 per 100,000 population. During the next two decades it increases, irregularly but persistently, to reach a peak of 217 in 1925. It remained high for the next seven years, dropped suddenly to 154 in 1933, and then, apart from a slight temporary increase during the years of the second world war, continued to fall rapidly reaching 20 per 100,000 population in 1950. In the period from 1930-50 the tuberculous death rate thus dropped a little over 90 percent. In the year 1952, when specific tuberculosis medical treatment was initiated (streptomycin, isoniazid and PAS) the death rate dropped to 14 per 100,000 population and the next year further down to 9 and since 1956 it never exceeded 5 per 100,000. From the year 1962 the tuberculosis mortality has never been over 2 per 100,000 population. The mortality rates have been broken down to reveal the role of age and sex specific death rates over some selected five year periods. Also the rates are shown according to different forms of the disease, pulmonary, meningeal and other forms. The highest proportionate mortality (60%) was observed in the 15-19 year age group between 1926 and 1930. From 1911 to 1930 tuberculous meningitis caused a remarkably high number of deaths, fluctuating between 20 and 50 per 100,000 population. Since 1956 not a single death from this form of the disease has occurred. Up to that year the highest meningitis death-rate consistently occurred in infancy and early childhood. Sex-specific tuberculosis death rates indicate that in every age-group the disease is more dangerous to women. Between 1941 and 1945, when the combined mortality-rate began to drop sharply, it was the rate for the males, which was first affected. Due to the very steep decline in tuberculosis mortality especially from 1952 tuberculosis mortality figures can no longer be considered the right criterion for the spread and course of the disease. The infection and morbidity rates are from then on the best measures of the prevalence and course of the disease. Tuberculosis infection-rates obtained through tuberculin testing on a comparatively broad scale, especially in school children 7-13 years of age, show a progressive reduction in tuberculosis infection in the country as a whole. These tuberculin surves on school children were initiated by the district health officers in the second decade of the century and therefore now extend over 60 years. The procedure of the tuberculin surveys and the methods used are mentioned. The shortcomings of these surveys and their importance are discussed. The value of the surveys is considered doubtful as long as the examinations are performed without any guidance or coordination. About the year 1930 the total percentage tuberculin tested in the age group 7-13 years was a little over 10 percent. In the year 1935 the director of tuberculosis control sent all the health officers instructions on how to perform the tuberculin testing together with some encouragement to perform such surveys. That year about 43 percent of the 7-13 years population was tested and in 1945 the percentage was 75. Between 1965 and 1970 the attendance percentage was 85. The tested 7-13 years age group showed in 1935 26.1 percent positive reaction, in 1945 10.1 percent, in 1955 5.3 percent and in 1970 0.7 percent. In 1970 0.2 percent of the 7 years old children reacted positively and 1.1 percent of those 13 years of age. the decline of the infection rate in this age group is remarkable. The very few BCG vaccinated children were excluded from the surveys. In the tuberculosis surveys made in the years 1940-1945, which covered 12 medical districts or parts thereof, extensive tuberculin examinations were performed. The results of these surveys showed that the infection rate was higher among male adults than females. This difference was notable after the age of 15 and especially in isolated and thinly populated rural districts. In urban and more thickly populated rural districts the infection rate was much higher. BCG vaccination was first used in Iceland in 1945. Only few persons were vaccinated in the first two years. In 1948 a systematic vaccination was proposed in the country to supplement the tuberculosis-control plan. The vaccination was particularly meant for the age group 12-29 where the risk of infection appeared to be greatest. However, at the end of the year 1950 a total of only about 6,900 persons had been vaccinated mostly groups of school children, young adults and contacts of tuberculosis cases. Most of the children and adults were born between the years 1929 and 1936 but in none of these years did the vaccination exceed 15 percent of those born in any one of the years concerned. Because of the rapid decline in the tuberculosis infection rate, morbidity and mortality in the country this vaccination plan was abandoned and changed at the end of the year 1950. After that only few groups of people were vaccinated, i.e. tuberculosis contacts, medical students, student nurses, adults studying abroad and persons who asked for vaccination. Between 1950 and 1970 only about 7,000 people have been vaccinated. So the total number of BCG vaccinations up to the end of 1970 has not exceeded 14,000 in the country. Therefore it seems most unlikely that the relatively few BCG vaccinations, given in recent years can be expected to have had much influence in speeding up the downward trend of the disease in the country. (ABSTRACT TRUNCATED)