The Occurrence, Recrudescence, and Worsening of Asthma in a Population of Young Adults: Impact of Varying Types of Occupation

doi:10.1378/chest.116.3.614

Chest

Volume 116, Issue 3, September 1999, Pages 614-618

https://doi.org/10.1378/chest.116.3.614 Get rights and content

Objective

To describe the rates of exacerbation of existing asthma and incidence of new disease in Israeli men during military service.

Design

All 17-year-old Israeli nationals are obliged by law to appear at the Israel Defense Forces (IDF) recruiting office for medical examination. The medical history of army recruits was noted during the 30-month period after their induction into the IDF, and medical examinations were performed by pulmonary specialists in all suspected cases of asthma. The duty status of the soldiers in combat units (CUs), maintenance units (MUs), and clerical tasks was related to their asthma status.

Results

Of a total of 59,058 recruits, 1.0% developed asthma during the 30 months of this study; of those in CUs, 1.2% developed asthma; of those in MUs, 0.8% developed asthma; and of those performing clerical tasks, 0.6% developed asthma. The relative risk for developing or worsening of asthma was related to both the preexisting asthma status of the recruit and the environment in which he carried out his military service. The annual incidence of occupational-related asthma in MUs was found to be 800/million: five to six times the rates reported elsewhere.

Conclusions

Service in CUs was associated with an increased frequency of exacerbation of asthma among recruits with previous disease and with the appearance of disease de novo. “Normal” conscripts with a history of childhood asthma are at a higher risk of developing overt asthma when compared to subjects with no such history. We found a 25% relative excess of incident cases of asthma in soldiers posted in MUs compared to those performing clerical tasks [(0.8 to 0.6%)/0.8%]. This difference is probably attributed to the difference in occupational hazards in these categories. Further studies are needed to determine if this represents the elicitation of underlying preexisting airway lability by new work demands or other environmental conditions, or if this represents a new development of airway lability because of specific immune or nonimmune factors.

Section snippets

Source of Data

All 17-year-old Israeli nationals are obliged by law to appear at the Israel Defense Forces (IDF) recruiting office for medical examination. We included in the current study all the recruits to the IDF between January 1, 1992, and December 31, 1994 (> 95% of the Jewish male population aged 18 years old). We made use of the IDF database and followed up all the soldiers 6 weeks after their induction into the IDF in order to eliminate cases of asthma and/or bronchial hyperreactivity overlooked at

Results

Table 1summarizes the follow-up results in subjects with no history of asthma (category O). One percent of subjects with a negative asthma history at the time of induction developed new asthma. The relative risk (RR) for developing asthma was significantly higher among subjects posted in CUs and MUs than it was among subjects performing clerical tasks (2.04 and 1.4, respectively).

Table 2shows the results in subjects with clinical remission for at least 3 years (category A). The recrudescence of

Discussion

The current study has documented the fate of a group of almost 60,000 young adults with varying degrees of morbidity due to asthma after their induction to the IDF and for 30 months thereafter. The risk of either developing asthma de novo or of worsening of preexisting asthma has been related to service in CUs, which is more risky than service in MUs, which in turn is more risky than service in clerical tasks.

Many mild asthmatics suffer from exercise-induced asthma, and it is important to use

Conclusion

Service in CUs tends to unmask previously mild cases of asthma that were not disabling, and to induce the appearance of asthma in subjects who had never suffered from the disease previously. Service in MUs and in a clerical situation poses less threat than the CU environment with the risk being the slightest in the group performing clerical tasks. According to this study, 25% of new onset asthma in subjects occupied in maintenance jobs is probably attributed to the difference in the

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Military service-aggravated asthma improves at two-year follow-up
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Many factors can aggravate asthma symptoms during military service, such as recurrent respiratory infections, physical exercise, and exposure to cold air, allergens or other dusts. An increased frequency of asthma exacerbation among recruits who already have the disease, and a new onset of asthma are reported as being associated with military service in combat units.4 Recognition of the risk factors for more severe asthma during and after military service can be useful for planning the criteria of exemption at call-up.
During military service young men (age 19–21 years) are exposed to many predisposing factors for asthma. We aimed to study the short-term prognosis of asthma after the military service.
All 216 men with verified asthma in 2004–2005 from the register of the Central Military Hospital were included in the study. A questionnaire was mailed to them in autumn 2007 and the 146 responders (68%) formed the final study population. Asthma severity was evaluated during military service according to the medical records of the subjects and two years later based on the questionnaire using modified GINA guidelines. The results on lung function and allergy tests during military service and asthma history were used as predictors of asthma severity at two-year follow-up.
Two groups of asthmatics were identified: those who already had asthma when entering the military service (n = 71, 48.6%) and those, who had a new onset of asthma during the service (n = 75, 51.4%). Overall asthma was less severe at two-year follow-up than during military service (p = 0.036). Both during military service and at two-year follow-up, asthma was milder among the men, who had a new onset of asthma during military service. Atopy (p = 0.002), number of positive skin-prick tests (p = 0.005) and higher total serum IgE (p = 0.001) were significant predictors for persistent asthma at follow-up.
Asthma, which had aggravated or started during military service, was significantly less severe two years later. The degree of atopy was a major determinant of the two-year prognosis of asthma after military service.
Asthma hospitalizations among US military personnel, 1994 to 2004
2007, Annals of Allergy, Asthma and Immunology
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Although rates of asthma hospitalization among some populations have increased significantly,15 other studies indicate rates have stabilized or declined.16,17 Although it has been estimated that up to 25% of asthma is occupationally related,18,19 with some occupations associated with an increased risk of developing asthma,20–22 results have been mixed and risks difficult to quantify.18,23,24 The current study investigates the association of incident asthma hospitalizations with certain demographic variables among active-duty military members during the last decade.
Acute asthma attacks strike unpredictably and may lead to hospitalization in otherwise healthy individuals. The burden of asthma hospitalization on the US health care system has greatly interested health care workers, many of whom see the incidence of asthma as increasing.
To examine the annual incidence of hospitalization and the frequency of subsequent hospitalization for asthma among all active-duty US military personnel between 1994 and 2004 and to determine demographic and occupational risk factors of asthma hospitalization within this generally healthy US population.
Annual demographic and occupational data were combined with electronic hospitalization records for patients with a discharge diagnosis of asthma. Using Cox proportional hazard modeling, the authors investigated demographic and occupational risk factors for asthma hospitalization.
Women, married persons, health care workers, enlisted personnel, US Army personnel, and older persons were found to have a significantly greater risk of asthma hospitalization. Yearly rates of hospitalization declined from 22.3 per 100,000 persons to 12.6 per 100,000 persons between 1994 and 2004.
Although these data have some limitations, they suggest that the burden of asthma hospitalizations in the large, healthy population of US military personnel has declined during the last decade. The decrease in hospitalization potentially reflects improved outpatient management strategies.
Health surveillance for asthma in the US Navy: Experience of 9,185,484 person-years
2005, Annals of Epidemiology
Citation Excerpt :
Asthma may not readily be detected during screening for military service (5). Of 59,058 Israeli army recruits, 1% developed asthma during the first 30 months, with exercise-associated symptoms as an early indicator (6). Few systematic studies of the incidence of first hospitalizations for asthma in young adult populations have been published (7, 8).
To measure trends and demographic risk factors for hospitalization for asthma.
Time trends and demographic risk factors, for hospitalized asthma (1CD-9-CM Code 493) were analyzed by measuring age-specific and age-adjusted first hospitalization rates in a defined population of active-duty enlisted members of the US Navy worldwide during 1980–1999, consisting of 9,185,484 person-years.
There were 3911 patients first hospitalized for asthma, including 2916 men and 995 women. The age-adjusted incidence rate of first hospitalization for asthma was three times higher in women than men, 110 per 100,000 person-years (95% confidence interval [CI], 104–117), compared with 35 per 100,000 person-years (95% CI, 33–37), respectively (p < 0.0001). The rate in black women was twice as high as in white women, 186 per 100,000 person-years, compared with 99 per 100,000 person-years, respectively (p < 0.001). The rate in black men was higher than in white men, 45 per 100,000, compared with 34 per 100,000 (p < 0.001). Age-adjusted rates in women doubled from 73 per 100,000 in 1980–1983 to 159 in 1997–1999 (p for trend < 0.01), while those in men remained stable.
Age-adjusted incidence rates of first hospitalization for asthma were three times as high in women as in men, and doubled during the period between 1980 and 1999. The rates in black women were twice as high as in white women. The reasons are unknown.
Asthma in remission: Can relapse in early adulthood be predicted at 18 years of age?
2005, Chest
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In the context of assessing young adults for future employment, some authorities recommend that asymptomatic individuals with a history of asthma should be screened out on the grounds of increased risk. This is particularly so for the armed services,8,9 but also applies to police forces, firefighters, and certain other occupations, eg, aluminum smelting. Such constraints are often applied because of the nature of the work to be undertaken, and to reduce overall risks in the working environment should the affected individual be rendered incapable of performing the work safely or satisfactorily.
To determine the frequency of relapse of asthma in young adults in remission at 18 years of age, during a follow-up period of 8 years, and to identify possible prognostic markers for relapse
Longitudinal study of birth cohort (n = 1,037) born in New Zealand in 1972–1973
University hospital research clinic
Participants were assessed at 9, 11, 13, 15, 18, 21, and 26 years of age using a respiratory questionnaire (all ages), spirometry (all ages), bronchodilator response (18 years and 26 years of age), methacholine challenge (9, 11, 13, 15, and 21 years of age), and allergen skin-prick testing (13 years and 21 years of age)
Approximately one third of study members (35%) with asthma in remission at 18 years of age relapsed by 21 years or 26 years of age. Atopy and lower FEV₁/FVC ratio at 18 years of age were significant independent prognostic factors for relapse in multiple logistic regression analyses. Increased responsiveness to methacholine (provocative concentration < 8 mg/mL) or bronchodilator (improvement in FEV₁ ≥ 10%) at 21 years of age were more common among those with relapse, but the positive and negative predictive values for a previous positive methacholine challenge test result at 15 years of age were low. Asthma after relapse was generally mild (mean FEV₁ 97.1% predicted). Totally new adult asthma developed by 26 years of age in 9% of study members who had no asthma or wheezing at any time up to 18 years of age
Subsequent relapse of previously diagnosed asthma in remission at 18 years of age occurs in one in three young adults. Such relapse is not easily predicted, especially by measurements of airway responsiveness. A history of asthma currently in remission should not be used to prejudice employment opportunities for young adults
Clinical characteristics of unexpected death among young enlisted military personnel: Results of a three-decade retrospective surveillance
2004, Chest
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Interestingly, according to our registry, the partial contribution of asthma to unexpected death increased over the years from 3 of 52 cases to 13 of 151 cases, however, this difference did not reach statistical difference. These findings are concordant with data originating from the United States, where a rise in death due to asthma from 1,674 cases (0.8 per 100,000 population) in 1977 to 5,667 cases (2.1 per 100,000 population) in 1996 was recorded in the general population.21 The low incidence of unexpected death in young adults has questioned the effectiveness of mass screening in this population.
To explore the causes of sudden and unexpected death in a young and healthy military population, to examine the various patterns of diseases associated with these tragic events, and to investigate the factors found to be associated with this grave outcome.
We retrospectively investigated 151 cases of Israeli military personnel who died unexpectedly over a 30-year period. We collected all the available medical records, autopsy results, and investigation committee reports.
A total of 151 cases of sudden and unexpected death occurred among enlisted military personnel during the period. Cardiac disorders caused 47% of deaths, followed by neurologic causes (17%) and pulmonary causes (11%). In 30 events (20%), the cause of death remained undetermined. Symptoms (eg, syncope, chest pain, palpitations, and others) occurred prior to death in 52 cases (34%). Asthma was the most common risk factor in our study population having been previously recognized in 10 cases (6.7%). Eight of the 13 subjects with asthma died following an acute asthmatic attack.
Cardiac events are the leading cause of unexpected death in young healthy people. The frequency of subjects with asthma was found to be higher than that in the general age-adjusted population.
Methacholine challenge testing in Reserve Officer Training Corps cadets
2001, Chest
Citation Excerpt :
The best correlate with the onset of symptoms was viralinfection followed closely by a PC20FEV1 that fell below 4 mg/mL and a family historyof asthma. A recent study of active-duty Israeli servicemen estimated a new onsetof asthma at 1.2% in combat positions, 0.8% in maintenance positions, and 0.6% in clerical positions over a 30-monthinterval.20 In addition, 10 to 20% of troops with knownhistories of asthma had recrudescence of symptoms during that interval.
To determine the prevalence of positive results for methacholine challenge tests in asymptomaticReserve Officer Training Corps (ROTC) cadets with no history of asthma.
Prospective, blinded cohort comparisonstudy.
Pulmonary diseases clinic in a US Armytertiary-care medical center.
One hundredthree college students who were undergoing a physical examinationbefore entering active duty. Group 1 subjects, 58 men and 5 women with an average age of 22.7 years, had no symptoms or personal history of asthma. Group 2 patients, 34 men and 6 women with an average age of22.2 years, had a history or recent suggestive symptoms of asthma.
Methacholine challenge testing usingconcentrations of 0.025, 0.25, 2.5, 10, and 25 mg/mL for a total doseof 188 inhalation units or until FEV₁ had declined by20%.
Group 2 had significantly morepatients with positive results for methacholine challenge testsor reversible airflow obstruction at baseline (23 of 40 patients[57.5%]) than group 1 (8 of 63 patients [12.7%]; p < 0.05). The cadets in group 1 with positive results for methacholine challengetests reacted with a 20% decline in FEV₁ at the followingconcentrations: 25 mg/mL (188 IU), 2 patients; 10 mg/mL (64 IU), 4patients; and 2.5 mg/mL (13.8 IU), 2 patients. Using values calculatedfor the provocative concentration of a substance causing a 20% fall inFEV₁ and the new American Thoracic Society criteria, fourpatients would have borderline bronchial hyperresponsiveness (4 to 16mg/mL) and three patients (4.8%) would have mild bronchialhyperresponsiveness (1 to 4 mg/mL).
Asymptomatic US Army ROTC cadets with nohistory of asthma have possible false-positive responses tomethacholine at concentrations > 0.25 mg/mL.

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Chest

Clinical InvestigationsAsthmaThe Occurrence, Recrudescence, and Worsening of Asthma in a Population of Young Adults: Impact of Varying Types of Occupation

Objective

Design

Results

Conclusions

Section snippets

Source of Data

Results

Discussion

Conclusion

Chest

Lancet

Chest

National survey of prevalence of asthma among children in the United States: 1976–1980

Pediatrics

Changes in asthma prevalence: two surveys 15 years apart

Arch Dis Child

Is the prevalence of asthma changing?

Arch Dis Child

Has the prevalence of asthma increased? Evidence from a national study of health and growth in 1973–1986

BMJ

Total population survey of the frequency and severity of asthma in 17-year-old boys in an urban area in Israel

Thorax

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

BMJ

The rising trend in allergic illness: which environmental factors are important?

Clin Exp Allergy

Outcome of childhood asthma in mid-adult life

BMJ

Differences in airway responsiveness between children and adults living in the same environment: an epidemiological study in two regions of New South Wales

Eur Respir J

Clinical Investigations
Asthma
The Occurrence, Recrudescence, and Worsening of Asthma in a Population of Young Adults: Impact of Varying Types of Occupation