Documentation for asthma.dat (free format)

  variable       code
  ---------    -------------------------------------------

1  Gender       0 Female
                1 Male

2  Origin       1 Israeli
                2 Western
                3 Asian
                4 North African

3  Period       1 First
                2 Second
                3 Third

4  Area         1 Tel_Aviv
                2 Haifa
                3 Jerusalem
                4 Tiberias
                5 South
                
5  Cases        Number with asthma

6  Examined     Number examined

--------------
There are 120 records.

Data taken from:

"Effects of time, sex, ethnic origin, and area of residence on 
prevalence of asthma in Israeli adolescents" by

Arie Laor, Leon Cohen, Yehuda L Danon      BMJ 1993; 307:841-844

               
A B S T R A C T

OBJECTIVES: To study effects of time, sex, ethnic origin, and 
area of residence on prevalence of asthma in Israeli 
adolescents.

DESIGN: Retrospective survey of asthma from computerised 
medical draft records of conscripts examined up to the end of 
1989.

SETTING: Five regional centres in Israel.

SUBJECTS: 443,186 conscripts (262,836 males and 180,350 
females) aged 17-18 who were born over a nine year period.

MAIN OUTCOME MEASURES: Asthma determined by medical history, 
physical examination, and lung function tests at rest and 
after exercise.

RESULTS:

CONCLUSIONS:


I N T R O D U C T I O N

Asthma is a leading cause of chronic disease in young adults, 
and there is some evidence that its frequency and severity 
are increasing.(1) This is difficult to assess confidently, 
however, because of a lack of reliable figures from 
population studies that used uniform diagnostic criteria.(2) 
Few studies have been made of large cohorts(3-5) and fewer 
still have been based on nearly a whole population.(6)

Our study made use of the database of conscripts of the 
Israeli Defense Force. This information allowed us to 
investigate the prevalence of asthma, based on uniform 
diagnostic criteria, among nearly all the Jewish population 
aged 17-18 in Israel over a decade. Thus any changes that we 
found could not be due to different diagnostic criteria or 
biased by sample selection. The data also allowed us to 
evaluate the effect of ethnic origin, demographic variations, 
sex, and time on the prevalence of asthma.

S U B J E C T S   A N D   M E T H O D S

We examined the records of 443,186 subjects, more than 95% of 
Jewish males and 80% of Jewish females aged 17-18 in Israel 
who were born over nine years. The characteristics of the 
computerised database which held these records have been 
described.(7) The study population had completed their 
medical draft examination by the end of 1989. During this 
examination the subjects had been asked whether they had ever 
been diagnosed as having asthma, and whether they suffered 
from recurrent wheezing, nocturnal cough, or wheeze after 
exertion. All subjects who had reported one or more of the 
above symptoms in the three years before the examination were 
referred for examination by a pulmonologist.

The examination by the pulmonologist included a detailed 
medical history, physical examination, and spirometry at 
rest. Normal spirometry at rest was defined as a forced 
expiratory volume in one second of more than 70% of the 
predicted value. All subjects, except those with overt 
clinical signs and spirometric evidence of severe airway 
obstruction, also performed an exercise test. This included 
running at 5 km/h on a treadmill inclined at 10 degrees for 
six minutes while breathing room air (22C, 50% relative 
humidity). Lung function was measured at five and 10 minutes 
after completion of the exercise test, and the percentage 
fall in forced expiratory volume in one second was 
determined. Asthma was diagnosed in subjects who required 
regular antiasthmatic treatment; had a history of one or more 
of the symptoms related to asthma in the three years before 
the examination; or had a forced expiratory volume in one 
second that was less than 70% of the predicted value at rest 
or that fell by more than 10% after exercise.

CLASSIFICATION OF SUBJECTS   The conscripts were divided into 
three groups by their birth year (each group covered three 
years but exact dates cannot be given for reasons of national 
security) and into four ethnic groups based on their fathers' 
or grandfathers' (if the father was Israeli born) country of 
birth. The ethnic groups were Israeli (conscript, father, and 
grandfather born in Israel), Western (conscript, father, or 
grandfather born in Europe, America, or South Africa), Asian 
(conscript, father, or grandfather born in an Asian country), 
and north African (conscript, father, or grandfather born in 
north Africa). The examinations had been made in five 
regional centres, and since 98.5% of the conscripts had been 
examined in their local regional centre they could be divided 
into five groups by their area of residence. The regional 
centres were Tel-Aviv (the central coastal area; 
industrialised, hot, and relatively humid), Haifa (the 
northern coastal area; industrialised but less hot and 
humid), Jerusalem (a mountainous inland area; less populated 
and industrialised and relatively dry), south (mainly the 
Negev desert; sparsely populated and less industrialised), 
and Tiberias (an inland rural area; not densely populated and 
hot and dry).

STATISTICAL ANALYSIS 

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