• Vol 9 • March 2007
Morbidity among Male Adolescents
In Israel, most adolescents are examined by a physician prior
to their conscription into the army. This nationwide medical ex-
amination is a potential source for assessing the state of health
of Israeli youth and for observing trends in the prevalence of
selected diseases over the years. Twenty years ago, Kark et al. 
published a study on the prevalence of selected diseases among
17 year old Israeli males examined in recruitment centers, and
compared their findings to cohorts of adolescents who had been
drafted in 1957–61 and 1977–78 . They concluded that the
prevalence of asthma and diabetes mellitus type 1 had increased
and that the prevalence of tuberculosis had decreased.
In the last 20 years a major demographic change occurred in
Israel due to massive immigration from Ethiopia and the former
Soviet Union . Also important is the significant progress in
diagnostic technology during this period. For example, 20 years
ago an echocardiogram was not part of the routine examination
for heart murmurs and diagnoses were largely based on physical
examination. Today most cardiac diagnoses are made by echo-
cardiogram, which may cause a bias in the reported prevalence
of heart defects. The aims of the present study were to examine
trends in the prevalence of common diseases in Israel in the
last 50 years and to examine whether ethnicity and immigration
influenced the prevalence of these diseases.
Subjects and Methods
The National Military Service Act requires all 17 year old Israelis
to present themselves at local recruitment centers for the
purpose of classification for military service. All Jewish, Druze
and Circassian males are obliged to serve in the military and
therefore undergo this physical examination. Arab citizens are
exempt from service, as are ultra-Orthodox Jews. Most boys
are examined (94% of those born in 1965–66 and 80% of those
born in 1986–87). Girls who declare themselves to be Orthodox
religious are exempted from service and are not examined. The
study was performed in males because of the relative complete-
ness of data.
The health examination includes a medical history uptake,
detailed physical examination and urinalysis. Documentation
of reported conditions is requested from the family physician.
Additional tests and referral to specialists are performed if
needed. Diagnosed conditions are categorized by diagnosis and
severity according to a standard classification manual.
The study group included all males who were examined in the
recruitment centers during 1992–94 and 2003–04. Comparisons
were made with reports on three similar cohorts in 1957–61,
1977–78 and 1982–84. Previous studies showed that the preva-
lence of diseases varies according to ethnic origin. We examined
the effect of origin on the prevalence of diseases by stratifying
the 2003–04 cohort according to the origin of the examinees. The
Background: Most Israeli males aged 16–17 undergo a thorough
medical examination prior to recruitment into the army. During
the last 50 years, extensive data have been gathered enabling
a study of time trends in the prevalence of common diseases in
this age group.
Objectives: To examine the current prevalence of common
diseases, compare the results with those of previous cohorts,
and assess the influence of the massive immigration during the
Methods: The health examination at the recruitment centers
includes a medical history, complete physical examination, and
review of medical documentation provided by the family physician.
If needed, additional tests and referral to specialists are ordered.
The prevalence of selected diseases and severity was drawn from
the computerized database of the classification board. Two cohorts,
1992–94 and 2003–04, were examined and compared with three
previous cohort studies in 1957–61, 1977–78 and 1982–84. Data
were stratified according to origin and country of birth.
Results: The prevalence of asthma increased dramatically during
the years from 10.2 per 1000 examinees in 1957–61 to 111.6 per
1000 examinees in 2003–04. The prevalence of tuberculosis declined
and then increased from 0.6 per 1000 adolescents in 1982–84 to
2.4 per 1000 adolescents in 2003–04. The prevalence of type 1
diabetes mellitus increased from 0.2 cases per 1000 examinees
in 1957–61 to 0.8 cases in 1977–78 and 1982–84 and 0.9 cases
per 1000 examinees in 2003–04. The prevalence of severe heart
defects and severe epilepsy declined in the last 20 years (1.4 and
1.7 cases per 1000 examinees in the 1982–84 cohort to 0.4 and
0.3 cases per 1000 examinees in the 2003–4 cohort respectively).
The patterns of disease prevalence were different for immigrants:
tuberculosis was more common while asthma and allergic rhinitis
were less prevalent.
Conclusions: The prevalence of common diseases among
adolescents in Israel has changed over the last 50 years. There is
a different pattern for immigrants and for those born in Israel.
Trends in Specific Morbidity Prevalence in Male Adolescents in Israel
over a 50 Year period and the Impact of Recent Immigration
Alon Farfel MD1, Manfred S. Green MD PhD2,3, Tzipora Shochat MsC1, Iris Noyman MD1, Yeheskel Levy MD1
and Arnon Afek MD1,3
1 Medical Corps, Israel Defense Forces, Israel
2 Israel Center of Disease Control, Tel Hashomer, Israel
3 Sackler Faculty of Medicine Tel Aviv University, Ramat Aviv, Israel
Key words: prevalence, asthma, tuberculosis, diabetes mellitus, Israel
A. Farfel et al.
• Vol 9 • March 2007
information was collected from the computerized system of the
Israel Defense Force. The sizes of the cohort populations are not
presented for national security reasons. For statistical analysis,
chi-square tests were used for categorical variables (prevalence
The prevalence of selected diseases in the 1992–04 and 2003–04
cohorts as compared to three previous cohorts (1957–61, 1977–78
and 1982–84) are presented in Table 1. The prevalence of asthma
has consistently increased during the last 50 years from 10.2
cases per 1000 males in the 1957 cohort to 111.6 per 1000 males
in the current cohort. The prevalence of tuberculosis was 18.3
per 1000 males in the 1957 cohort; it decreased dramatically
in the 1977–78 and 1982–84 cohorts to less than 1 per 1000
and increased to 2.4 per 1000 males in the current cohort. The
prevalence of heart defects decreased between 1957 and 1977 but
consistently increased from 1977 until the current cohort. The
prevalence of severe heart defects and severe epilepsy dramati-
cally decreased in the 1992–94 and 2003–04 cohorts [Table 1].
In order to examine the effect of recent immigration, we strati-
fied the last cohort by country of birth of the draftees [Table 2].
The prevalence of asthma and allergic rhinitis was significantly
lower among adolescents who were born in Ethiopia than in
adolescents of other origins. On the other hand, the prevalence
of tuberculosis was much higher in adolescents from Ethiopia
and the former Soviet Union compared to other countries of
birth (allergic rhinitis was evaluated only in the last cohort).
There were no cases of diabetes mellitus among draftees born
in Ethiopia. There was no significant change in the prevalence
of heart defects and epilepsy between the different countries of
Figure 1 shows the prevalence of asthma in cohorts from 1957
to 2004, which is rising consistently. Figure 2 shows the preva-
lence of tuberculosis in the 1992–94 and 2003–04 cohorts with
stratification by native Israelis and immigrants. The prevalence
of tuberculosis in native Israelis persistently decreased, and the
overall increase in the prevalence of tuberculosis in Israel in the
last 20 years is due to the immigration.
Table 1. Prevalence of selected diseases per 1000 male examinees
aged 17–18 by induction cohorts in Israel between 1957 and 2004
1957–611977–78 1982–841992–94 2003–04
10.2 33.640.8 72.3111.6
Tuberculosis 18.3 0.90.6 1.12.4
Diabetes mellitus types 1+2 0.2 1.10.9 0.61.1
Diabetes mellitus type 10.20.8 0.8 0.5 0.9
Severe heart defects*
* A severe disease is a disease that disqualifies the examinee from being drafted.
Table 2. Prevalence of diseases per 1000 males aged 17–18 years, in
Israel, according to birth country in the 2003–04 cohort
119.3 103.983.995.927 27.8< 0.0001
Allergic rhinitis92.191.4130.568.52714.8< 0.0001
Tuberculosis 0.41.98.32.1050.0< 0.0001
Diabetes mellitus types 1+21.200.8000054
Diabetes mellitus type 1 0.900.50000.6
Severe heart defects*
7.96.5 8.0 6.805.60.94
* A severe disease is a disease that disqualifies the examinee from being drafted
Figure 1. Prevalence of asthma among 1000 males aged 17–18
years, in Israel, by induction cohorts between 1957 and 2004
Figure 2. Prevalence of tuberculosis among 1000 male
adolescents, in Israel, according to year and immigration status
1992-1994 Tuberculosis 2003-2004
• Vol 9 • March 2007
Morbidity among Male Adolescents
To the best of our knowledge Israel is unique in that the major-
ity of the country’s 17 year olds undergo a thorough medical
examination, the purpose of which is medical screening prior to
induction into the military. This event enables the examination
of time trends in the prevalence of selected disease prevalence
in Israel over the last 50 years. Furthermore, the dynamic nature
of the Israeli population with its massive immigration waves
permits the study of the effects of ethnic origin and immigration
on disease prevalence. The aims of this study were to illustrate
trends in the prevalence of selected diseases and to study the
effect of origin and immigration on the prevalence of diseases.
The 1940–43 cohort was unique because most of the draftees
were immigrants who arrived in Israel after the Second World
War; in the other four cohorts most of the draftees were born
in Israel although their parents were born in different coun-
tries, which possibly affected their lifestyle. The current cohort
includes two large subgroups: the majority of adolescents were
born and raised in Israel, but a significant number were born
and partly raised in Ethiopia and the former Soviet Union. We
also examined a cohort from 1992–94 in which the effect of the
immigration wave was milder than in the current cohort. The
presentation of a variety of morbid conditions provides a general
view of the health status of Israeli adolescents in the last 50
years. We will discuss each disease separately.
There was a consistent and significant increase in the prevalence
of asthma in the last 50 years. Since the diagnostic criteria of
asthma have not changed in the last 50 years, these findings
indicate a genuine increase in the prevalence of asthma in Israel.
This increase could be due to changes in lifestyle or environ-
mental hazards in Israel. A similar trend was found in other
studies of younger Israelis and in other countries [3-8]. Another
possible explanation for this phenomenon can be found in the
theory that inversely connects the prevalence of asthma and
other atopic diseases to the incidence of infectious diseases. The
T-helper cells are differentiated to type 2 rather than to type 1
and contribute to the development of atopic diseases .
In order to neutralize the effect of immigration we examined
the prevalence of asthma in native Israelis excluding immigrants
in the 1992–94 and 2003–04 cohorts [Figure 1]. We found that
without the immigration the prevalence of asthma was even
higher. The prevalence of asthma and allergic rhinitis in ado-
lescents of Ethiopian origin was lower than in adolescents from
other origins. These differences can be due to genetic reasons
. The difference according to origin and immigration suggests
that both genetic and environmental etiologies are involved in
the evolution of asthma.
We found a significant increase in the prevalence of diabetes
mellitus type 1 from 1957–61 to 1982–84 and a mild increase
between 1992–94 and 2003–04. The results are similar to those
found in other studies in Israel and the United States [10,11].
Since the diagnostic criteria for diabetes mellitus in the IDF have
not changed in the last 12 years, we believe that a genuine in-
crease in the prevalence of diabetes mellitus type 1 has occurred
in Israel. In comparison, by origin we found that the prevalence
of diabetes mellitus type 1 and type 2 are higher in adolescents
of western, Asian and Soviet Union origins than in adolescents
of Israeli and Ethiopian origins. For each origin the prevalence
of diabetes mellitus type 1 is lower in adolescents who were not
born in Israel than in adolescents who were (data not shown).
This difference cannot be explained by genetic changes and may
be due to the dietary habits in Israel or from an environmental
hazard not yet identified.
A significant increase in the prevalence of tuberculosis in adoles-
cents occurred from 1982–84 to 2003–04, in contrast to the con-
stant decline from the 1957–61 cohort to the 1982–84 cohort. In
order to determine whether the increase in prevalence is due to
immigration, we examined the prevalence of tuberculosis in the
1992–94 and 2003–04 cohorts in native Israelis and immigrants
[Figure 2]. The prevalence among native Israeli adolescents has
not increased since 1982–84. The increase in the prevalence of
tuberculosis in Israel in the last 20 years is therefore the result
of the immigration.
As expected, the prevalence of tuberculosis is dependent on
origin, with higher rates among Ethiopian adolescents (3.7%)
and adolescents from the former Soviet Union (0.66%) than in
adolescents from western countries and Israel (0–0.03%). These
results are similar to those of studies conducted in the USA
There was an increase in the prevalence of heart defects in male
adolescents between 1982–84, 1992–94 and 2003–04. However,
during the same time there was a decrease in the prevalence
of severe heart defects, which disqualify inductees from military
service. This trend was also found in studies in other countries
. Origin and immigration status did not affect the prevalence
of heart defects.
A possible explanation for our findings is the improvement in
imaging techniques and the increased use of echocardiography.
This enables the diagnosis of milder heart defects, such as mitral
valve prolapse, mitral regurgitation and tricuspid regurgitation,
that might previously have been overlooked. The decrease in the
prevalence of severe heart defects could be due to the progress
in pediatric cardiology and heart surgery over the last 20 years or
from prenatal diagnosis. Today, some heart defects can be cured
or treated to the extent of enabling a normal life.
Our study revealed trends in the prevalence of selected chronic
diseases among 17 year old males in Israel over the last 50 years.
In general, the prevalence of infectious diseases decreased while
IDF = Israel Defense Force
A. Farfel et al.
• Vol 9 • March 2007
the prevalence of atopic diseases increased. Immigrants are af-
fected, but their descendents who are born in Israel tend to have
a health profile similar to that of the general population. This
could be due to adopting an Israeli lifestyle and diet. Moreover,
as Jews of various origins are intermarrying more and more, the
genetic differences that probably influenced the different disease
prevalence are suppressed and lifestyles and diets are becoming
mixed. The recent immigration of adolescents from Ethiopia with
their unique health characteristics will most likely also undergo
the melting-pot process. It will be interesting to see the trends
in their health status in the next generation.
1. Kark JD, Kedem R, Reavach M. Medical examination of 17 year
olds before military service as a national resource for health
information. Isr J Med Sci 1986;22:318–25.
2. Health in Israel 2003. Tel Hashomer: The Israel Center for
Disease Control, 2004;235:19–41.
3. Goren AI, Hellman S. Has the prevalence of asthma increased in
children? Evidence from a long term study in Israel. J Epidemiol
Community Health 1997;51:227–32.
4. Auerbach I, Springer C, Godfrey S. Total population survey of
the frequency and severity of asthma in 17 year old boys in an
urban area in Israel. Thorax 1993;48:139–41.
5. Miralls-Lopez F, Guill’n-Grima E, Aguinaga-Ontoso F, et al.
Bronchial asthma prevalence in childhood. Allergy Immunol 1999;
6. Pearce N, Weiland SK, Keil U, et al. Self reported prevalence
of asthma symptoms in children in Australia, England, Germany
and New Zealand: an international comparison using the ISSAC
protocol. Eur Respir J 1993;6:1455–61.
7. Nystad W, Magnus P, Gulsvik A, Skarpass IJ, Carlsen KH.
Changing prevalence of asthma in school children: evidence of
diagnostic changes in asthma in two surveys 13 years apart. Eur
Respir J 1997;10:1046–51.
8. Shohat T, Golan G, Tamir R, et al. Prevalence of asthma in 13-14
year-old schoolchildren across Israel. Eur Respir J 2000;15:725–9.
9. Leung DY. Allergy and the immunologic basis of atopic disease.
In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook
of Pediatrics. 17th edn. Philadelphia: WB Saunders, 2004:747.
10. Shamis I, Gordon O, Albag Y, Goldsand G, Laron Z. Ethnic differ-
ences in the incidence of childhood IDDM in Israel (1965-1993).
Diabetes Care 1997;20:504–8.
11. Incidence of IDDM between the ages 0-17 years in Israel in 1998
– the Israel IDDM Registry Study Group – IIRSG. Harefuah 2002;
12. Nelson LJ, Schneider E, Wells CD, Moore M. Epidemiology of
childhood tuberculosis in the United States, 1993-2002: the need
for continued vigilance. Pediatrics 2004;114:333–41.
13. Meberg A, Otterstad JE, Froland G, Lindberg H, Sorland SJ.
Outcome of congenital heart defects – population-based study.
Acta Pediatr 2000;89:1344–51.
Correspondence: Dr. A. Afek, 52 Hakeshet Street, Rosh Ha’ayin,
Phone: (972-3) 737-9542
Fax: (972-3) 737-7033
In an article by Erica Sodergren et al. (more then 200 authors,
from 78 instituitions), the authors report the sequence and
analysis of the 814-megabase genome of the sea urchin
Strongylocentrotus purpuratus, a model for developmental and
systems biology. The sequencing strategy combined whole-
genome shotgun and bacterial artificial chromosome (BAC)
sequences. This use of BAC clones, aided by a pooling
strategy, overcame difficulties associated with high hetero-
zygosity of the genome. The genome encodes about 23,300
genes, including many previously thought to be vertebrate
innovations or known only outside the deuterostomes. This
echinoderm genome provides an evolutionary outgroup
for the chordates and yields insights into the evolution of
The genome of the sea urchin Strongylocentrotus purpuratus
Inflammatory bowel diseases (IBDs) such as Crohn’s dis-
ease and ulcerative colitis are thought to be caused by an
inappropriate immune response to commensal intestinal
bacteria. There is strong evidence that these disorders
have a genetic component; for example, individuals carrying
specific sequence variants of the NOD2/CARD15 gene are
at increased risk. Now, in a genome-wide association study,
Duerr and colleagues find that a rare sequence variant of
the gene encoding the receptor for interleukin-23 (IL23R)
significantly lowers an individual’s risk of developing IBDs.
Interleukin-23 is a cytokine that has attracted increasing
attention because of its role in a wide range of chronic
inflammatory diseases in mouse models, including IBDs,
multiple sclerosis and arthritis.
Genes and inflammatory bowel diseases