\
'
San Fernando Valley State College
,,SENSITIVITY
AND TUBERCULOSIS
IN
13 SCHOOL DISTRICTS
A thesis submitted in partial sa~isfaction of the
requirements for the degree of Master of Science in
Health Science
by
Frank·
Harader
. Robert
.
1:
July;·· ·1967
I
I'
I:
.;·
The thesis of Frank Robert Harader is approved:
San Fernando Valley State College
July, 1967
ii
TABLE OF CONTENTS
PAGE
LIST OF TABLES AND FIGURES
v
ACKNOWLEDGEMENTS
vi
ABSTRACT OF THE THESIS
vii
CHAPTER
I.
II.
INTRODUCTION
. . . . . . .
1
Statement of the Problem
3
Importance of the Study .
3
Limitations of the Study .
3
Definitions of Terms for the Purpose
of the Study . • . • . . . .
4
REVIEW OF THE LITERATURE
Tuberculin Test as a Measure of Prevalence
III.
7
8
Standardization of the Tuberculin Test
10
Specificity of the Tuberculin Test
11
Summary
14
15
PROCEDURES
Purpose of the Study
15
The Study Universe and Sample
16
Methodology
17
Testing Techniques
18
Compilation of the Data
19
iii
Table of Contents (continued)
PAGE
CHAPTER
••
19
ANALYSIS AND DISCUSSION OF DATA
21
Census Tracting Procedures
IV,
V.
General Statement • . .
21
Methods of the Analysis
23
Discussion of the Analysis
29
SUMMARY AND CONCLUSIONS.
31
Summary
31
.•
32
Conclusions
34
REFERENCES CITED
APPENDIX
......
38
iv
LIST OF TABLES AND FIGURES
PAGES
TABLES
I
1966 School District Data • . . . . . . . . . . . . . .
24
FIGURES
I
Correlation Study:
311 Eighth Grade Students Who Reacted Positively
to tuberculin by Census Tracts - Percent of the
Population with Spanish Surnames and an Eighth
27
Grade Education (or Less) · · · · . · . . • .
II
Correlation Study:
115 Reported Active Tuberculosis Cases by
Census Tract - Percent of the Population with
Spanish Surnames and an Eighth Grade Education
(or Less)
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28
ACKNOWLEDGEMENTS
The author is indebted to the Tuberculosis Control Department of the
Los Angeles County Health Department for 1966 tuberculosis data.
Special thanks are given to the staff members of the Biostatistics Research Laboratory and the Computer Facility at UCLA, for assistance and
computer time necessary for the data analyses.
Appreciation is extended to Professors Wilfred C. Sutton and John M.
Weiner for their critical appraisal and valuable suggestions.
Special grat-
itude is extended to Professor L. H. Glass, the chairman of this thesis
committee for his direction, guidance and stimulation.
His leadership con-
tributed invaluably to this work.
The author sincerely expresses his thanks to Margery St. John,
Barbara Luckey and Merwin L. Noble of the Tuberculosis and Health Association of Los Angeles County for their assistance and encouragement.
vi
I
1.
ABSTRACT
SENSITIVITY AND TUBERCULOSIS IN
13 SCHOOL DISTRICTS
by
Frank Robert Harader
Master of Science in Health Science
July, 1967
Health authorities have surmised that a relationship existed between
tuberculin· sensitivity (induration) and reported cases of tuberculosis in identical geographic areas for the same period of time.
This study, encompassing 13 Los Angeles County School Districts in
which eighth grade students were tuberculin tested in 1966, attempted to
study the suggested relationship.
Students who reacted positively to the tu-
berculin tests were identified by census tracts, as were also the active reported cases of tuberculosis from the 13 school districts during 1966.
The possible relationship between tuberculin sensitivity and tuberculosis incidence rates in each of the 13 school districts was analyzed.
1.
Rank order comparison of tuberculin sensitivity and incidence
rates for the 13 school districts was employed.
2.
Seventeen social characteristics for each of the 13 school districts
i
\.
vii
were plotted against induration values of the students reacting
positively to the tuberculin tests.
It was hypothesized that if
any of the social characteristics indicated a relationship to induration on a school district basis, then a similar relationship
would exist between those characteristics and incidence rates.
Two social characteristics - percent of the population with Spanish Surnames
and percent of the population with an Eighth Grade Education (or Less) were found to have a significant relationship to induration ·on a school district basis.
The relationship between these population characteristics in the
positive reactors was similar to that observed for active tuberculosis cases.
A stronger relationship was observed when these characteristics were ana-
lyzed on the basis of census tracts.
Results of the analysis showed a cor-
relation coefficient of 0. 71 when the Percent Spanish Surname was plotted
against the percent of the population with an Eighth Grade Education (or
Less) for the 311 student reactors.
The two characteristics when plotted
for the 116 active cases of tuberculosis by census tracts showed a correlation coefficient of 0. 59.
An apparent relationship between tuberculin sensi:-
tivity and tuberculosis cases in the same geographic areas is postulated.
viii
CHAPTER I
INTRODUCTION
Since its development over eighty years ago, the tuberculin test has
been used primarily as a case finding device by public health agencies.
The
private physician and the clinician, after investigating its use as a treatment
agent, refined the test for use as a diagnostic tool in ruling out diseases
other than tuberculosis.
In the early 1930's, the California Tuberculosis and Health Association
conducted an extensive school tuberculin testing program in an effort to detect unknown cases of tuberculosis in both school children and personnel.
During this period, it was common for personnel to be found with active undetected disease.
When compared to current data, a high percentage of pos-
itive reactors was found.
Following World War II, mass chest x-ray surveys became popular
and the tuberculin testing programs, as a case finding technique, were reduced.
In 1956, the California Tuberculosis
and Health Association again
promoted tuberculin testing programs in eleven areas of the state to demonstrate the value of tuberculin testing as a case finding device and to study
the pattern of infection among school children.
In 1962, the Interagency Council for Tuberculosis Control in Los
c
1
2
Angeles County began administering the tuberculin test to eighth graders in
selected" school districts.
From 1962 through 1967 the program included all
school districts with an eighth grade enrollment.
of the districts were tested annually.
Approximately 20 percent
The purpose was to study tuberculin
sensitivity as an index of tuberculous infection in the community.
The program was adopted because various health authorities had suggested that there might be a relationship between tuberculosis prevalence
rates, as measured by tuberculin sensitivity, and the incidence rates of newly reported active cases in the general population in each school district.
If
such a relationship could be observed, it was the intention of the Council to
use this technique as a means of uncovering cases of tuberculosis.
cases would then be treated.
These
As a result, fewer students would come into
contact with active cases and the positive reaction rate would be reduced.
This would enable the Council to meet its goals of reducing the positive reaction rate of eighth graders to 1 percent or less by 1970.
In addition, the initiation of chemoprophylaxis to those eighth graders
having positive reactions over 10 mm. induration would also enable the Council to meet its goal of reducing the annual incidence rate 10 percent per year.
Various studies have indicated that 7 5 percent of future cases of tuberculosis
develop from the individuals with the positive tuberculin reactions. (6: 12)
3
A.
Statement of the Problem
The purpose of this study was to explore the relationship between 1966
prevalence rates, as measured by tuberculin sensitivity of the eighth grade
population, and the tuberculosis incidence rates of the general population for
the same period in 13 Los Angeles County School Districts.
B.
Importance· of the Study
Another dimension would be added to the eighth grade testing program
by determining if the prevalence rate, as measured by tuberculin sensitivity,
is a predictor of the tuberculosis incidence rate for the general population in
the same community (school district}.
As such, a continuation of the pro-
ject would permit the testing of a population which is accessible as a measure of the tuberculosis incidence rate.
_c.
Limitations of the Study
For the purpose of this study the following limitations were accepted:
1.
The percentage of students who volunteer to participate would in-
fluence the validity of the testing results.
It would be difficult to ob-
tain a true measure of infection if significant numbers of students
with possible positive reactions did not participate in the testing program.
2.
The idea that one can compare the reactor rate to. the rate of
p
known cases of tuberculosis would be influenced by unreported cases
in the community.
Good case reporting varies with the cooperation
4
obtained from private physicians and institutions.
3.
In recent years the specificity of the tuberculin test has been
challenged by various researchers.
It is possible that false positive
reactions may be caused by fungal and atypical mycobacterial infections.
4.
Students who have been immunized with BCG (bacille Calmette
Guerin) react positively to the tuberculin test.
Usually parents re-
port a history of such an immunization when signing the student's consent card.
D.
Definitions of Terms for die Purpose of the Study
To clarify the interpretation of the data and the review of the litera-
ture, the following definitions were established for the study:
Definitions of terms:
Commull.icable disease: · A communicable disease is an illness which is caused by a specific infectious agent or its toxic products.
Such a disease may
be transmitted directly from reservoir to susceptible host such as from an
infected person or animal, or indirectly through the agency of an intermediate plant or a.nimal host, a vector, or the inanimate environment.
Tuber-
culosis is spread through droplet nuclei as a respiratory infection.
Contact:
An individual who has been in close association with an active case
of tuberculosis is a designated contact.
Usually contacts are divided into
i
!.
5
two categories
according to the person - - close or familial, and casual
(the latter being a friend or school associate).
Census tract:
Census tracts ·are small, permanently established, geographic
areas usually with 4, 000 average population.
They remain stable over a
period of years so that comparative demographic studies can be made.
Census tracting is the technique of locating addresses of cases in a
Census Tract Street Index to place each case in its proper tract for statistical purposes.
Incidence rate: The number of new active cases reported in one year per
hundred thousand population.
Infected person:
Persons infected with tuberculosis may have clinically evi-
dent disease or non-clinically-evident disease.
The later condition may be
detected only through sensitivity to the tuberculin test.
Intracutaneous· test (Mantoux): A skin test administered by injecting intradermally the desired concentration of purified protein derivative (PPD) into
the cleansed skin of the forearm.
Induration: Th,e induration is the hard, w,:hite, usually raised area at the
site of injection.
The red inflamed area (erythema) which may surround the
induration is not measured.
Transverse measurements are .taken and re-
corded in millimeters as the largest diameter of induration at right angles
to the long axis of the arm.;; .
6
Prevalence rate:
For this study, prevalence rate means the number of stu-
dents per hundred who would react positively to tuberculin.
School District:
School districts comprise specific geographic areas with
definite legal boundaries.
Each school district may contain whole and parts
of census tracts.
Tuberculins: At the present time there are two preparations of tuberculin
being widely used:
Old Tuberculin (OT):
Tuberculin (OT) is made by heat-sterilizing
cultures of tubercle bacilli, filtering off the dead bacilli and evaporating the filtrate to one tenth of its original volume.
Purified protein derivative (PPD): Tuberculin (PPD) consists of the
active protein principle obtained from filtrates of autoclaved cultures
of .tubercle bacilli.
PPD-S is the batch designation of the World
Health Organization Antigen which has been used since 1952.
CHAPTER II
REVIEW OF THE LITERATURE
The Tuberculin Test, which was first introduced by Robert Koch (1)
as a curative agent in 1890, has become widely used in determining levels
of tuberculous infection.
Extensive controversy followed Koch's announcement
at the International Congress of Medicine, August 9, 1890, that he had discovered a
11
curative agent" against tuberculosis.
On November 22, 1890, The Lancet of London commented editorially:
The publication by Professor Koch of an account of the method
of treating tubercular disease which, as the result of years of patient
research, he has discovered, may be taken as evidence that he himself is satisfied of its efficacy. No doubt this publication has been in
a sense forced on him by the extraordinary anxiety manifested on all·
sides to learn something tangible concerning a remedy about which the
greatest possible expectation has been raised. From one point of view,
therefore, this early publication is to be depreciated, since it does not
contain any records of cases, or any account of the lines pursued by
the discoverer in the production of the remedy, and no exception can
be taken to a postponement of final judgment until all these facts are
before the profession. Nevertheless there are few men more worthy
of confidence than Professor Koch, whose whole record is that of the
patient, earnest seeker after the truth, and who has. alre:;tdy done so
. much to widen our conceptions of disease. That this is the general
opinion is shown by the reception given to the first intimations by him
that he was within reach of succeeding in his search for an antidote to
the tubercular virus. Such a statement from many another source
would have been received with more than incredulity, but this announcement, when made at the International Medical Congress, was v.elcomed as "glad tidings of great joy", for it was generally felt that
Robert Koch was a man who seldom made a statement which he coq.ld
not justify, and one who, in this particular instance, must have felt
7
8
the tremendous issues depending on his utterances. (9:2)
In the following months there was heated controversy on both sides of
the Atlantic as to whether Koch was justified in keeping secret the nature of
his fluid.
On December 13, 1890, however, Sir Joseph Lister of England
went on record in support of Koch:
... Koch, I believe, would not have published his method at all, had
it not been for great pressure brought to bear upon him, until he
could have produced it in a form capable of being revealed in every
detail ... And I must say that the carping against Koch on account of
what is spoken of as a "secret remedy'' can only proceed from absolute ignorance of the beautiful character of the man. (9: 2)
Although Koch's fluid failed as a curative agent, his observation of
the reaction of the tuberculous and nontuberculous individual to tuberculin
laid the foundation for one of the most widely used diagnostic tests in both
veterinarian and human medicine and the field of public health.
From his
observations developed the knowledge required to modify the tuberculin test
as a diagnostic tool.
The method of preparing "Old Tuberculin", as Koch's fluid is known
today, is still essentially the same as prepared by him in 1891. (9:3)
The Tuberculin Test as
a Measure
of Prevalence
The idea of using the Tuberculin Test to measure the prevalence of
tuberculous infection developed during the 1950s when the World Health Organization conducted mass testing programs in connection with BCG immunization projects in many countries:
9
.•. Although the tuberculin testing in the campaign is carried out primarily for the purpose of selecting persons for vaccination, it also
provides an indication of the prevalence of tuberculous infection. (19:36)
The frequency of positive reaction showed considerable variation from
country to country, ranging from 13 percent in Costa Rica to 75 percent in
Hong Kong.
For many countries the data accumulated constituted the only
available information on the prevalence of tuberculosis.
Watson (26:83) utilized the tuberculin testing of Edinburgh, Scotland
children to measure general infection rates.
Results of the tests showed a
decrease .in the positive reaction rate from 30. 5 to
tween 1954 and 1960.
13~
1 in 14 year olds be-
The decrease was found by Watson to coincide with
the drop in tuberculosis morbidity in specific geographical areas of Edinburgh.
Local and state tuberculin skin testing surveys have indicated the possibility of relationships between tuberculin sensitivity and morbidity rates.
Crummett, et al.,
(5:23) in a three-year tuberculin testing project in
Los Angeles County, found a relationship between tuberculin sensitivity rates
and tuberculosis incidence rates for health districts in certain selected school
districts in Los Angeles County.
In the three year period 1955-1958, 58, 094
children were skin tested.
The findings were summarized as follows:
10
School
District
Percent
Positive
Arcadia
Lincoln Hts. Par.
Antelope Valley
Compton
Covina
Centinela Valley
Downey
Whittier
1.9
6.0
5.9
10.3
6.7
4.9
3.6
5.7
*Incidence
Rates
24
77
47
47
24
24
47
24
Percent Participation
36
- 80
- 51
- 51
36
- 36
- 51
- 36
72
78
57
51
47
59
77
'76
I
*Incidence rate per 100, 000 population.
In another California study conducted by Blum, Hesse, Kent and Lichtens tiger, in 1957-1958, in eleven areas of the state, it was found that the
pattern of tuberculin sensitivity agreed with area morbidity rates:
Of 123, 934 elementary school children, enrolled in 399 schools, in
ten selected areas of California, When testing is done competently,
using 5 TU with 8 mm. as cutoff point, a most acceptable guide for
follow-up examination and case-finding results.
The frequency of positive reaction and the degree of sensitivity as
represented by size of reaction are related to the frequency of exposure to M. tuberculosis. Rates of conversion and levels of infection paralleled incidence of active disease. (3: 183)
Standardization of the Tuberculin Test
Various procedures for administering the tuberculin test have been
used throughout the world.
Standardization of the Tuberculin Test has been
encouraged by both the National Tuberculosis Association (18:34) and the
World Health Organization. (26:63)
In arriving at a decision to use 5 tuberculin units as the testing antigen in the eighth grade program, precedence was established, not only be
the World Health Organization projects, but also by the Committee on
11
Diagnostic Skin Testing of the American Thoracic Society.
This Group stated
early in 1958, that 5 tuberculin Units of PPD administered intradermally was
the preferred test for screening. (1:3)
This same Committee reaffirmed its
stand in 1963 as follows:
On the basis of the information available,' the following suggestions
are offered for the guidance of those who use tuberculin tests for
diagnostic or screening purposes.
For both screening and diagnostic purposes, the Mantoux with a standard dose of 5 TU (0. 001 mg.) of PPD is the most accurate test.
Skillful administration and careful reading are essential. (1:4)
The Committee further suggested that the size of all reactions should be recorded in quantative terms so that any excess of small reactions would be
detected.
Follow-up of those individuals with larger reactions is of para-
mount importance according to the Committee.
The small reactions, if en-
countered in undue large numbers, may indicate problems with cross reactions caused by either the fungi infections or the atypical mycobacteria.
Specificity o£ Tuberculin Test
Medical researchers in recent years have challenged the specificity of
the tuberculin test.
Is the test specific for M. tUberculosis (human tuber-
culosis) or are cross reactions from other mycobacteria causing false positive reactions?
In addition, the time lapse between administration of the
test and its interpretation has also been questioned.
Palmer has stated that nontuberculous infections cause many of the
positive reactions observed in human beings:
12
The results of reactions observed in human beings are corroborated
by results of experimental studies of guinea pigs. Some of the animals are infected with virulent tubercle bacilli, some with nonphotochromogenic mycobacterium of the "Battey" type, and some are not
infected. Intracutaneous tests with standard mammalian tuberculin
(PPD-S) and the PPD antigen prepared from the Battey organism
(PPD- B) showed that although cross reactions occur with both types
of infection, the homologous antigen usually produced a larger reaction than the heterologous antigen. Frequently histograms of the sizes
of reactions to PPD-S for theoretical populations and uninfected guinea
pigs, revealed patterns of sensitivity similar to those observed in
human populations.
Parallel studies of patients in tuberculosis hospitals from whom only
typical tubercle bacilli or "Battey" type organisms have been recovered gave results like those found in guinea pigs. (20:415)
Edwards (8:32) found in testing over 200, 000 Navy recruits a high percentage of small reactions - 0-5 rom. indurations.
Recruits retested with
atypical antigens were found to produce large size indurations for Battey mycobacterium.
Silverstone and Abrahams (23:489) reported in 1961 that in children
13-14 years of age in Brisbane and Cairns, Australia, both M. fortuitum
and M. avis influenced the tuberculin testing results in those two areas.
Belgium studies (11: 165) reported in 1962 indicated that the interpretation of the tuberculin test has become more complicated.
Two phenomena
have been recognized in the last few years:
One such phenomenon is the weakening of the collective sensitivity to
tuberculin - a weakening which is observed in countries where regression of the tuberculin reaction is more pronounced. The other
phenomenon is the probable existence of "non-specific" allergy from
other than tuberculous infection. (11: 166)
From 1962-1964 Huxtable and Johnson (15:5) administereq multiple antigen skin tests to hospitalized patients at Los Angeles Childrens Hospital.
13
Over 1, 000 children were tested with four antigens with the following results:
It was noticeable that 91. 5 percent reacted negatively to the four anti-
gens. While 3. 9 percent reacted to one antigen, 2. 4 percent to two
antigens, 1. 4 percent to three, and 0. 5 percent to all four antigens.
The four antigens administered were PPD-B (Battey), PPD-G (Gause),
PPD-Y (Yellow) atypical mycobacteria antigens and PPD-S (Seibert
tuberculin). ( 15: 6)
In another study conducted in England by Stewart, et al. , (24: 13) two
types of population were studied using the tuberculin test as a measure of infection; the findings were compared to morbidity and used to determine whether cross reactions to tuberculins were present.
One community was basi-
cally rural in· nature and the other urban industrial.
Both human and bovine ·
tuberculins were administered in the testing of 8, 839 school children.
Results
demonstrated that reactions to the bovine tuberculin were greatest in the area
where known bovine tuberculosis was present although these reactors also reacted to the human tuberculin.
In the other area, where there was a high
incidence of human tuberculosis, reactions were largest to the human tuberculin, but cross reaction was obtained to the bovine tuberculin.
In conducting mass tuberculin skin testing surveys, the problem of determining the proper time lapse between administration and interpretation of
the test has often been raised.
Multiple reading of large numbers of stu-
dents has not proved feasible.
Support for the "one reading" technique has
developed, with the most recent study being that of Duboczy in 1961. (7:63)
He investigated the single and multiple reading techniques in 308 hospitalized
tuberculosis patients with proved tuberculosis.
His study showed that the
14
maximal intensity of the reaction to tuberculin was found from 24 hours to 7
days after infection with the highest intensity at 48 hours.
Summary
Three distinct phases in the development and use of the tuberculin
test are noted in summarizing the review of the literature.
Historically the
test progressed from a "curative agent" in the 1890's to a useful diagnostic
tool.
In the 1950's, the test acquired an additional value as an instrument
for measuring the tuberculous infection in a community.
Definite recommendations regarding the type of antigen, its administration and interpretation were reviewed.
The Eighth Grade Tuberculin Test-
ing Program, described in this study, followed those skin! testing techniques
recommended by the National Tuberculosis Association and the World Health
Association, including the administration of 5 tuberculin units of Purified Protein Derivative intradermally and read 48 hours after injection.
CHAPTER III
PROCEDURES
The experimental design and procedures applied in this study are outlined in this chapter.
The purpose of the study is detailed in Section 1.
study universe and sampling plan are described in Section 2.
The
The method-
ology employed in the tuberculin testing program is detailed in Section 3.
The procedures followed in obtaining addresses of newly reported cases of tuberculosis in 1966 and their subsequent census tracting are reported in
·Section 4.
Section 1
Purpose of the Study
Health officials have surmised that there may be a relationship between prevalence rates as determined by tuberculin sensitivity of eighth graders in a school district, and the tuberculosis incidence rate of newly reported cases in a community.
The purpose of this study was to explore in 13
school districts the possible relationship of these two rates.
15
16
Section 2
The Study Universe and Sample
The study universe was limited to eighth graders enrolled in the following Los
Ange~es
County School Districts during 1966:
District
East Whittier
Eighth Grade Population
1,422
El Monte
853
Hawthorne
559
La Canada
391
Lancaster
702
Lynwood
524
Montebello
1, 764
Norwalk - La Mirada
2,040
Pomona
1, 116
Redondo Beach
713
Rosemead
257
Rowland
799
Valle Linde
114
.
These school districts were included in the tuberculin testing programs
during the spring semester of the school year 1965-1966 and fall semester
1966-1967.
~--------~
17
The incidence rate in the general population for each school district
was computed from the master file of newly reported active cases for 1966
in Los Angeles County.
Preference was given by the investigator to 1966
reported cases of tuberculosis, because it was the first year the health department reported such information by census tracts.
In addition, it was
the first year, since consolidation of the Los Angeles County and City Health
Departments, that case reporting and record keeping were considered to be
stabilized and accurate.
Section 3
Methodology
In his position as Coordinator of the Eighth Grade Tuberculin Testing
Program, the investigator was responsible for development of the POLICY
STATEMENT AND GUIDE , the official tuberculin testing manual of the Interagency Council for Tuberculosis Control in Los Angeles County.
The man-
ual details the organizational pattern, testing techniques and compilation of
data for the project.
Organizational Pattern:
Prior to the initial approach to enlist the cooperation
of each school district superintendent, a letter was mailed from the County
Superintendent of Schools outlining the Eighth Grade Tuberculin Testing Program and asking the support of each school district.
The original communi-
cation was followed by a letter, from the chairman of the Interagency Council
for Tuberculosis Control, designating the individual who would make contact
18
and be responsible for the coordination of the program in each school dis·trict.
In most instances, the superintendent delegated the responsibility for
district coordination to the Special Services Office or School Health Services
Office.
Once such a person was appointed, a preliminary meeting was set
up to bring the nurses, Parent Teachers Association representative and the
Los Angeles County Health Department Officials from both the district and
the central tuberculosis controller's office together to establish the dates for
testing and reading the tuberculin tests.
At this meeting, the educational
program to be launched prior to sending out the consent cards for parental
signatures, was planned.
The health department also outlined plans for pro-
viding chest x-rays to the positive reactors through the mobile unit which
was placed in the vicinity of each school after the testing program.
Community involvement was encouraged through the Parent Teachers
Association and through special news releases emanating from the District
Superintendent's Office.
Testing techniques:
In order to obtain as much uniformity as possible in ad-
ministering and reading the tuberculin tests, one physician administered all
the tests in the thirteen school districts and one public health nurse read all
the tests.
The intracutaneous test (Mantoux) was performed by injecting 0. 1 mi.
of 5 Tuberculin Units of PPD into the cleansed volmer surface of the left
forearm.
19
Reactions were .read 48 hours after the test was administered,
The
induration was measured and recorded in millimeters as the largest diameter
of induration at right angles to the long axis of the arm.
Compilation of. data:
Four data forms (Appendix) were used to obtain perti-
nent data which included the name and address of the child, parental signature, date of test and reading, reaction results, list of positive reactors
giving each measurement of reaction, teachers' census of enrollment and
number actually tuberculin tested and read.
Following each testing program,
a verifying form was received from the public health nurse giving the final
results of each program.
From the described forms, the total number of students tested, percentage of participation, and positive reaction rates were compiled for each
school district.
Census tracting of each positive reactor was accomplished
by using the school district census tract map in conjunction with the official
county census tract map since many of the tracts are divided by school district boundaries.
Section 4
Census Tracting Procedures
It was imperative that great diligence be employed in census tracting
each address from the list of new active tuberculosis cases.
It was known
that the positive reactors lived within the school district; but in tracting
20
each address of the newly reported cases, each address had to be carefully
checked with both the school district census tract map and the official county census tract map to insure that if it were split by school district boundaries, the address was properly placed in the correct part of the census
tract belonging to the respective school district (Appendix).
CHAPTER IV
ANALYSIS AND DISCUSSION OF THE DATA
A.
GENERAL STATEMENT
An attempt was made to determine if the occurrence of tuberculin
sensitivity manifested by eighth grade students enrolled in 13 Los Angeles
County School Districts was related to the presence of active tuberculosis
cases residing in the same geographic areas.
Three approaches to deter-
mine the possible existence of such a relationship .were employed:
1.
The rank order comparisons of the tuberculin sensitivity and incidence rates for the 13 school districts were analyzed.
2.
In the second approach, 314 of the 9, 377 eighth grade students
were identified as having sensitivity reactions (induration) greater than 5 rom. as a result of the testing program in 1966.
Seventeen social indices (10) were measured for each of these
314 students.
Each index reflected
ulation within the school district.
a characteristic of the
pop-
Those indices chosen were
believed to be related to the occurrence of positive tuberculin reactions.
If a correlation between the degree of induration (sens-
itivity reaction) and a population characteristic could be demon.strated, then it was hypothesized'that a similar correlation might
21
22
exist between the occurrence of active cases of tuberculosis and
this characteristic.
Population characteristics chosen were as
follows:·
Income:
Percent $4, 000 (or Less)
Density:
Persons Per Square Mile
Youth:
Percent 0-19 Years Old
Productive Ages:
·Aged:
Percent 20-64 Years Old
Percent 65 Years and Older
Percent White Individuals
Percent Negro Individuals
Percent Spanish Surname
Percent Other Ethnic Population
Percent Unemployed Males
Percent Eighth Grade Education (or Less)
Percent 1 year College (or MorE:)
Families as percent of Households
Percent of Families Separated or Divorced
Percent of Houses Dilapidated or Deteriorated
Youth and Aged per 100 Adults in Productive Ages
Youth Neglected per 1, 000
Two of the population characteristics - Percent Spanish Surname
and Percent Eighth Grade Education (or Less) - were found to be
significantly related to degree of induration. (6:468)
23
3.
In the third step of the data analysis, the characteristics - Percent Spanish Surname and Percent Eighth Grade Education (or
Less) - for each census tract in which the 314 individuals with
positive reaction resided were obtained.
The same information
was secured for the census tracts in which the individuals with
active tuberculosis resided in 1966.
The relationship between
the two population characteristics was determined for each group.
B.
METHODS OF ANALYSIS
Student participation percentages were examined for each school dis-
trict to determine if obvious selection problems existed.
From the numbers
of positive reactors and students tested and :read in each district, the tuberculin sensitivity rate was computed
Number Positive Reactors
Prevalence Rate =
X 100.
Number Students Tested
The tuberculosis incidence rates for each school district were computed
from census tracting reported active tuberculosis cases and the population
figures available for each district
100,000
Incidence Rate = Number New Tbc. Cases X
District Population
Inspection of Table I indicates that student participation was on the
average over 82 percent.
This figure compares well with the response in
students (78 percent) in the Los Angeles City School System for the school
·•
School
District
E. Whittier
8th Grade
Enroliment
1,422
TABLE I
1966 SCHOOL DISTRICT DATA
Number
Percent Number
Prev.
Tested
Tested
Positive
Rate
1,089
76.5
26
2.3
Total
Po:e.*
90,000
No. TB
·cases
5
Incidence
Rate
5.5
El Monte
853
734
86.0
14
1.9
75,500
17
21.1
Hawthorne
559
457
81.7
23
5.0
42,500
5
11.5
La Canada
391
307
78.5
11
3.6
27,500
0
0.0
Lancaster
702
605
86.1
29
4.7
35,000
5
14.0
Lynwood
524
432
92.4
10
2.3
50,000
9
18.0
Montebello
1,764
1,435
81.3
56
3.8
115,000
39
33.5
Nor., La Mirada
2,040
1,564
71.7
73
4.6
100,000
12
12.0
Pomona.
1,441
1, 106
76.7
25
1.3
100, 000
6
6. 0
869
701
80.7
22
3. 1
60,000
10
16.0
Rosemead
253
214
83.2
5
2.3
32,700
5
15. 0
Rowland
839
738
86.7
16
2.1
40,000
2
5.0
Redondo Beach
-
..
ooo·
. . ...
10~
Valle Linde
114
95
83.3
4
4.2
1
to.o
116
12.9
Totals & Averages
11,811
9,337
314
3.0
81.6
Los
Angeles
*Population figures were computed from data received from School Elections Department,
County Schools.
~
1:'-'
~
25
year 1965-1966. (13)
Positive reaction rates {column 5 - Prev. Rate) rang-
ed from 1. 3 to 5. 0.
Incidence rates (column 8 - Incidence Rate) ranged
from a high of 33. 5 in Montebello School District to a low of 0 in La Canada School District.
When tuberculin sensitivity rates were compared by ran-
king, there was no evidence of significant correlation between these two variates - tuberculin sensitivity rates and incidence rates.
Blum,
et
a:l., (3: 196) in the California Study, found a positive reac-
tion rate of 11. 1 percent in Spanish American children.
In the Los Angeles
County testing program between 1955-1958 (5:88), using the same testing
techniques as utilized in the Eighth Grade Testing Program, positive reaction
rates were found to be highest in those geographic areas with high percentages of Negro and Spanish American populations.
Each of these areas re-
ported a high incidence of tuberculosis for the same period.
These findings were used to suggest the possible existence of a relationship between social characteristics of the population and degree of induration and occurrence of active tuberculosis.
Seventeen population characteristics were determined for each school
district.
Correlation studies were performed to determine the degree of re-
lationship between each characteristic and induration.
The percent of the
population with an Eighth Grade Education (or Less) was observed to have a
correlation coefficient of 0. 171 with degree of induration.
The correlation
between induration and percent of the population with Spanish Surnames was
0. 178.
Both correlations were significant (P<. 05) for the sample of 314
26
students with positive reactions. (6:468)
The finding of a significant relationship between the two population
characteristics and induration values led to the third step in the analysis.
The relationship between Percent Spanish Surname and degree of induration in the census tract data was significant (correlation coefficient of
0. 220).
This latter relationship represented a slight increase from the cor-
relation coefficient of 0. 178 obtained from using school district data.
The
correlation coefficient for percent of the population with an Eighth Grade Education (or Less) and degree of induration, using census tract data, increased from 0. 171 for the school district data to 0. 230.
In the census tract com-
putations 311 individuals with positive reactions formed the sample.
Three
students were unable to be identified by census tract.
Two computations were employed to investigate the relationship between census tracts containing the 311 eighth grade students and the 116 active cases of tuberculosis.
The Percent Spanish Surname was plotted
against the percent of the population with an Eighth Grade Education (or Less}
for the 311 students.
Results of the analysis (Figure I) showed a correla-
tion coefficient of 0. 71 (P< . 05). (6:468)
When plotting the Percent Spanish Surname against the percent of the
population with an Eighth Grade Education (or Less) for the 115 cases of tuberculosis (Figure II), the correlation coefficient was 0. 59 (P<. 05).
case was unable to be identified by census tract.
One
27
Figure I
311 Tuberculin Sensitive Students
Relationship of Spanish Surname and 8th Grade Education (or less)
By Census Tract
80
*
%
Spanish 72
Surname
64
56
48
A
40
32
*5
.24
" * 4 35
16
..
*
25
8
3
E3
*
*
2 52
* *3 9
33 * • 3 4 I3 4
6 2 •2
2 *
8 "
5
I
I
1
I
l
13
26
39
52
65
% 8th
Grade Education (or less)·
The symbols represent census tracts, indicating the number of students in each:
Symbol
No. of students
2 thru 9
same
A
10
c
E
12
14
I
18
Correlation coefficient = 0.7060
Example:
(]) Two reactors in a census tract with
40% Spanish Surnames and 49%
8th Grade Education (or Less)
l ________
· _·-------·------~----------------~------~--------'-- __ ·: ----- ---'=---~--- -'·-~~---- -----------------------
28
Figure
II
115 Tuberculosis Cases
Relationship of Spanish
Surname and 8th Grade Education (or less)
By Census Tract
%
80
Spanish
Surname
72
64
56
48
39
40
*
32
24
*
•
•
.
16
..
8
2•
3
•
•
.. 2·
2
*
4 2
**
*
I
I
26
%8th
..
*2
.
• ••• 2• *
• 35 2*
13
*
2 4
Grade
*
2
•
2 A
I
Education
39
(or less)
52
The symbols represent census tracts, indicating the number of Tb cases in each:
Symbol
No. of cases
•
2 thru 9
same
A
10
Correlation coefficient = 0.5925
65
29
Discussion" of ,·the Amilysis
Ranking of the school districts by tuberculin sensitivity rates and tuberculosis incidence rates was unsuccessful in determining any noticeable relationship between the two factors.
In the study conducted by Blum, et al. ,
(3: 184) the pattern of tuberculin sensitivity agreed with area morbidity rates
in eleven areas of California.
It should be noted that this particular study
included 123, 934 elementary school students.
In the study promoted by the Los Angeles County Tuberculosis and
Health Association (5:23), two school districts out of eight (see page 10)
were found to have relationships between positive reaction rates and tuberculosis incidence rates for the areas tested.
Those two districts gave some
clues regarding the possible influence of social characteristics existing in a
community with respect to tuberculosis sensitivity rates and incidence rates.
Both districts contained high percentages of minority groups and low socioeconomic conditions.
Watson (26:83) found that a decrease in tuberculin reaction rates in
Edinburgh, Scotland, between 1954 and 1960 coincided with the drop in tuberculosis morbidity in specific geographic areas of that city.
During the 1965-1966 school year, 40, 055 junior high school students
,.
in the Los Angeles City School System (13) were tuberculin tested.
over-all positive reaction rate for those tested was 8 percent.
The
Those junior
high schools with over 8 percent positive reaction ranged from 9 to 22
percent.
30
When rank order comparison was made of those Los Angeles City
Schools with high tuberculin sensitivity rates and the health districts in
which each school was located, little relationship was revealed between tuberculin sensitivity and incidence of tuberculosis.
Possibly, correlation
studies, using social characteristics of the health districts and degree of induration, would indicate the same relationship as found in the eighth grade
data analysis (Figures I and II).
It is apparent that a more refined method
than utilized in this study is needed to investigate the relationships between
tuberculin sensitivity and incidence rates in common geographic areas.
The
existence of a significant negative relationship between tuberculin sensitivity
and tuberculosis incidence rates would not have posed a problem if such
were found.
Tuberculin sensitivity was found to be highest for the 4 to 6
year old child in the affluent areas of the county in the Nursery School Project (12:21) coordinated by this investigator.
in these same areas at the time of the study.
Low tuberculosis rates existed
One of the District Health
Officers stated that in the high socio-economic areas case reporting was
poor.
In many instances, he suggested, laboratory reports were made after
the individual had received a course of chemotherapy.
Children were infec-
ted, but active cases were not reported as such.
It may follow, therefore, that in those areas with good case detec-
tion and treatment, one would observe a high tuberculosis incidence rate and
a low tuberculin sensitivity rate.
In such areas the chain of infection would
be broken sooner than in those areas where one observed a low tuberculosis
incidence rate accompanied by a high tuberculin sensitivity rate.
CHAPTER V
SUMMARY AND CONCLUSIONS
A.
SUMMARY
In the field of tuberculosis control, much of the research has been
confined to the nature of the tuberculin testing agents, treatment and search
for new drugs.
The tuberculin test served originally as a ''curative agent".
late 1800's it has been used to establish a diagnosis of the disease.
Since the
When
the emphasis changed from tuberculosis control to eradication of the disease,
the tuberculin test then became useful in measuring community tuberculosis
infection levels.
The value of the tuberculin test has recently been extended
to the identification of susceptible individuals who are now placed on chemoprophylaxis.
The relationship between low socio-economic areas and high tuberculosis incidence, various social characteristics - alcoholism, ethnic groups
and single aged men - has been demonstrated epidemiologically.
With the
exception of the California study (3) and the Los Angeles County Project (5),
reported in Chapter II, the investigator found little in the literature regarding possible relationships between tuberculin sensitivity rates for school
..\
children and community tuberculosis incidence rates.
31
32
In this study, one point in time, 1966, was used to investigate the
relationship of tuberculin sensitivity of one segment of the population, namely, eighth graders in 13 specific school districts, to tuberculosis incidence
rates for the same geographic areas.
The investigation was accomplished by census tracting the data received after tuberculin testing programs were conducted in the 13 school districts.
Additional data on active tuberculosis cases were obtained from the
Los Angeles County Health Department for the census tracts included in each
of the specified school districts.
Three attempts were made to investigate the relationship between tuberculin sensitivity rates and tuberculosis incidence rates for each school
district.
The rank order comparison of the two rates by school districts re-
vealed no significant relationship.
When 17 social characteristics of the
school districts were studied, two characteristics were found to be related to
tuberculin sensitivity.
The relationships between these two characteristics
in the census tracts of the eighth grade student reactors and newly reported
active cases of tuberculosis were found to be similar.
This finding sug-
gested a possibility of relationship between tuberculin sensitivity and tuberculosis incidence rates in a common geographic area.
B.
CONCLUSIONS
l.
A relationship may exist between tuberculin sensitivity and tuber-
culosis incidence rates on a school district basis, but difficulty
is encountered in demonstrating this.
33
2.
An indirect measurement of the relationship between tuberculin
sensitivity and tuberculosis incidence may possibly be made
through their relationship to social characteristics of specific
census tracts.
3.
The mobility of the individual from birth to death in our present
society limits the value of area and census tract data in epidemiologic investigations.
REFERENCES CITED
...
34
REFERENCES
1.
American Thoracic Society. "Tuberculin Skin Testing Techniques:
Current Status," pp. 4, 1963.
2.
American Public Health Association. Control of Communicab'Ie Diseases in Man, Ninth Ed., New York, N. Y., 1960.
3.
Blum, Henrik L. , et al. "A Tuberculin Testing Survey of a School Age
Population in Eleven Areas in California," The American Review of
Respiratory Diseases, 1963, 87:181-199.
4.
Confrey, Eugene A., ed. "Tuberculosis," Administration of Community
Health Services, International City Managers Association, 1961,
pp. 369-385.
5.
Crummett, Duane 0. , et al. ~ Three-Year Tuberculin Testing Health
Education Project in SeleCted Public and Parochial School Districts
in Los Angeles County, Tuberculosis and Health Association of Los
Angeles Coul}ty, March, 1964, 35 pages.
6.
Dixon, Wilfred J. and Massey, Frank J. Introduction 'to Statistical
Analysis, McGraw-Hill Book Company, Inc., New York, 1957,
pp. 189-208, 468.
7.
Duboczy, B. 0. and Brown, B. T. "Multiple Reading Techniques,"
The American Reyiew .Qf Respiratory Diseases. January, 1961,
84:60-68.
8.
Edwards, Lydia B.
Annals, New York Academy of Science, 1963,
106:32.
9.
Edwards, Phyllis Q. and Lydia B. "Story of the Tuberculin Test,
From an Epidemiologic Viewpoint, II The American Review of Respiratory Diseases, 1961, 81: part 2, 47. pages.
·
10.
Freudenberg, Edward and Street, Lloyd. Social Profiles: Los Angeles
County, Welfare Planning Council, Los Angeles Region, July, 1965.
11.
Frohm, E. F. "Epidemiological Aspects of Tuberculin Sensitivity, 11
JoU:rrial Hygie·ne, Epidemiology, Microbiology and Immi:iriology,
(Prague) 1961, 5:160-167.
35.
"
36
12.
Harader, Frank R., et al. Tuberculous Infection Among Nursery
School Children in Los Angeles County. Tuberculosis and Health
Association of Los Angeles County, March, 1964, 35 pages.
13.
Health Services Branch, Los Angeles City Schools. "Report of Educational Unit for the Prevention of Tuberculosis, 11 1965-66.
14.
Hsu, Katherine, et al. "Today' s Concept of the Tuberculin Test, II
Diseases of the Chest, 1964, 46:648-661.
15.
Huxtable, Robert F., et al. "Atypical Mycobacteria: Multiple Skin
Testing Study" Unpublished Paper, Childrens Hospital, Los Angeles,
1966.
16.
Interagency Council for Tuberculosis Control in Los Angeles County.
"Minutes, Program Evaluation Committee, '' March, 1967.
17.
Interagency Council for Tuberculosis Control in Los Angeles County.
Policy Statement arid Guide - Eighth Grade Tuberculin Testing
Program, 1962, 14 pages.
·
18.
National Tuberculosis Association. Diagnostic Standards and Classification of Tuberculosis, New York, N. Y., 1961, 56 pages.
19.
Nyboe, J. "Efficacy of the Tuberculin Test, An Analysis Based on the
Results From 33 Counties," Bulletin World :Health O:rganization,
November, 1960, 22:5-37.
20.
Palmer, Carroll E. "Experimental and Epidemiological Basis for the
Interpretation of Tuberculin Sensitivity, II Journal of Pecliat:dcs,
October, 1959, 55:413-416.
21.
Personal Notes. United States Public Health Service Institute on Tuberculosis, National Jewish Hospital, Denver, November 29 - December 9, 1966.
22.
Scavlin, S. P. ''Five-Year Skin Testing Results," Diseases of the
ch-est, 1964, 45:38-60.
23.
Silverstone, H. W. and Abrahams, E. W. "The Results of Multiple
Antigen Testing in Southern Australia," Tubercle, April, 1961,
42:487-489.
24.
Stewart, C. J., et al. "Comparative Tuberculin Skin Testing of Human
Subjects, " Brilishiv.tedical J ourna.l, January 7, 1961, 7: 13.
37
25.
United States Department of Commerce.
Edition, January, 1966, 83 pages.
Census Tract Manual, Fifth
26.
Watson, W. N. B. ''Tuberculin Testing of School Children,
Officer, August, 1961, 106:83 .
.27.
WHO Tuberculosis Research Office. "Further Studies of Geographic
Variation in Naturally Acquired Sensitivity, 1t :BuHetin, World Health
6rgariizaticm, 1955, 12:63.
11
Medical
APPENDIX
..
'
38
:'
39
TEACHER'S TUBERCULIN TESTING ENROLLMENT FORM
THIS FORM SHOULD BE DELIVERED TO CLERK CHECKING YOUR STUDENTS' CONSENT FORMS ON THE DAY AND AT THE LOCATION THE
TUBERCULIN TESTS WILL BE ADMINISTERED.
School District
-----------------------
School._________________________
Teacher's Name______________ Room No.
____
Period.__
Total Enrollment in this period
·--------------------
Number of ·students with signed consent forms___________________________
Number of students without signed consent forms: ______.___________________
Tally reasons for students without signed consent forms:
_______
Previous Positive Tuberculin Reaction:.___
BCG Vaccination
Fear of Needle
Refusal on Medical Advice
Religious Objection
Other_ _ _ _ _Specify:___________________________________
Number of students absent for test._________
Number of students present for test._____.___
Form #1
40
INTERAGENCY COUNCIL FOR TUBERCULOSIS CONTROL
IN
LOS ANGELES COUNTY
SCHOOL SUMMARY SHEET OF POSITIVE REACTORS
School District
School
Date
Coordinator
Student's Name and Address
Parent's Name
!
Induration
One copy sent to Los Angeles County Health Department
One copy to the Tuberculosis and Health Association of Los Angeles County
One copy for the school files
Form #2
'
..
Please Print
Name (Last)
(First)
Home Address (Number)
(Street)
X-RAY CLINIC
;:,urvey ~·um No.
Husband or Father's First Name
~um
vate
MANTOUX CLINIC
Film Location
Home Telephone
City
Age m Yrs.
FEMALE D
MALE 0
(Check one)
Date of
Birth
Size of Film
Large
Mantoux Location
Small
REASON FOR EXAMINATION
Contact, 1st Exam.
1
MANTOUX RE-sULT-s
Negative
1
FILM IMPRESSION
Negative
TYPE OF SURVEY
1 Health Center
1
Contact, Re-exam.
Dept. Employee
or Vo unteer
·
Health Dept. Prenatal
!!eag!J_ .!Jept. Child
Health Conference
2
1+ (doubtful)5-9mm 2
Susp. TB urgent
2 Mobile
2
3
2+
10-19mm 3
Susp. TB routine
3 Outside Referral
3
4
3+
20+ rom
4
Calcifications
4
·5
4+
necrosis
5
Cardiovascular
5 Negative Report to Pt 1
6
Other Pathology
Scoliosis
6 Report to Patient
Refer to chest clinic
7 or pvt. M.D.
8 Refer to heart
Healt~
1
Mantoux Date
School Survey
6
Not read
Other.
7
Mantoux Dispositio
Repeat Doubtful Mantoux
8
Negative Report
1
Pleural Thickening
Self Referral
Remarks:
9
X-ray Survey
·M,anto¥1
epea Doubtful
2
Unsatisfactory
3
READING
Other
4
None
5
Los Angeles County Health Department
Division of Tuberculosis Control
TUBERCULOSIS SURVEY RECORD
RECOMMENDATIONS
2
3
4
mea.
5
9 Refer to other care.
Large film Requested 6
PA
R. Lat.
Lordotic
L. Lat.
C. 0. Use Only
Dist. of Residence
control No.
Form #26
H'>-
~
42
COUNTY OF LOS ANGELES
HEALTH DEPARTMENT
220 North Broadway
Los Angeles, California 90012
Dear Mrs.
The Tuberculosis and Health Association and the Los Angeles County Health
Department would like ·to thank you for your cooperation and management
during the Eighth Grade Testing Program at
The results of the tests are as follows:
Students Tested
Students Not Tested
Students Negative
Student Reactors
-
The results of the follow-up as interpreted at the local health centers or at
the private physicians' office are as follows:
We appreciate your interest in this project: Any questions you might have
in regard to this program will be gladly answered by
Very truly yours,
G.· A. HEIDBREDER, M. D.
Health Officer
J. K. VAN DEVENTER, M.D., M.P.H.
Chief - Division of Tuberculosis Control
JKV:MV/oo
cc: Mrs. Stimpson, PHNC, TB Control
Mrs.
TB & Health Association
File (2)
! !'
- - - - - - ' - - - - - - - - - - - - - - · - - - - - - - - · - · - · · - - · - · · · -·····
43
4335
(part)
4337 (part)
EL MONTE SCHOOL DISTRICT
;,
.
Census Tract
Divis ions