1 Department of Epidemiology and Biostatistics, Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon.
2 Epidemiology Unit, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
3 Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD.
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ABSTRACT |
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cardiovascular diseases; mortality; sex; social class; socioeconomic factors; stress; war
Abbreviations: CI, confidence interval; CVD, cardiovascular disease; RR, rate ratio.
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INTRODUCTION |
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Because of social, political, and religious tensions within the borders of Lebanon, which were exacerbated by conflicts in the Middle East, a civil war erupted in 1975 and continued with varying severity for almost 16 years. The prolonged years of war manifested themselves in various types of atrocities and violence, severely deteriorating economic conditions, a serious public health crisis, and a complete breakdown of services. Deaths in the family, injuries, kidnappings, and lost homes and properties were only a few examples of the events experienced repeatedly by many people in Lebanon.
In a small case-control study conducted 12 years ago, we found an association between events related to the war in Lebanon, as markers of stress, and the risk of arteriographically determined coronary artery disease (18). On the basis of these preliminary findings, we initiated a larger 10-year retrospective follow-up study among a cohort of middle-aged and older men and women to assess the long-term impact of multiple and repeated war-related experiences on CVD and all-cause mortality.
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MATERIALS AND METHODS |
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Between June 1993 and August 1994, trained interviewers (n = 10), all of whom were university graduates, rigorously solicited the help of neighbors, concierges, shopkeepers, and district registrars (Mokhtar) to trace 1,567 (87.7 percent) of the original cohort to assess vital status and exposure to war events during the period of civil strife. Those lost to follow-up differed significantly from those traced successfully by being older (age 63 and 61 years, respectively; p value = 0.011). Also, they were more likely to be widowed, to have a lower level of education, and to have been living in less crowded households in 1983. Loss to follow-up was not associated with either reported comorbidity (diabetes, hypercholesterolemia, hypertension) or behavioral risk factors (smoking, alcohol consumption) at baseline.
Markers of wartime stressors
The interview schedule for assessing war events was based, with modifications, on that used in our earlier case-control study among patients hospitalized for coronary artery disease (18). Information was collected on not only the occurrence of an event but also the year of occurrence and the relationship of the affected person to the study subject. The questionnaire contained three main sections. The first comprised a list of direct acts of violence, which were later aggregated into four homogeneous clusters according to the realm affected (human vs. property losses) and the person central to the event (self vs. immediate family members). Family members were defined as spouses, sons, daughters, grandchildren, and parents. Human losses included deaths, injuries, kidnappings, and serious threats taking the form of repeated telephone calls or home visits and not merely casual experiences on the road. Property losses included lost homes, workplaces, or other real-estate property. The other two sections of the questionnaire assessed work-related problems and displacements. The former included changes in occupation type and unemployment leading to forced early retirement, whether these events occurred to the subject and/or the main breadwinner in the household. A conservative measure of displacement was chosen: to avoid including short-term moves for reasons such as the summer vacation, displacement was judged to have occurred whenever subjects were obliged to leave their residence for a continuous period of more than 4 months.
To minimize differential recall bias, interviewers were instructed to obtain the war-related data by proxy not only for deceased persons but also for the survivors. However, doing so was not always possible, particularly when the subject was present in the household during the interview. Approximately 15 percent of the interviews were conducted with the study subjects themselves; the others were conducted with a son or daughter (42 percent), the spouse (24 percent), a daughter-in-law (6 percent), a sibling (4 percent), or other relatives (9 percent).
Mortality outcome
For those subjects who had died, information on causes of death was obtained by interviewing the next of kin, a close relative who had lived with the case in the same household and was the main caregiver in the year preceding the subject's death. The interview, a "verbal autopsy," included details on the circumstances of the death event; symptoms, signs, and complaints suffered by the deceased around the time of death; a checklist of comorbid conditions; age at onset; and contacts with health services and injuries occurring 1 year prior to death. Data were coded for the underlying cause of death, according to the International Classification of Diseases, Ninth Revision, by a physician not involved in the study and blind as to exposure.
Data analysis
Two major endpoints were evaluated: CVD (International Classification of Diseases, Ninth Revision codes 390459) and all-cause mortality. Subjects whose underlying causes of death were attributed to injuries, intentional and unintentional (6.3 percent; 15 men and 11 women), were excluded from our analysis of the associations with all-cause mortality. Because of the potential for multiple experiences, the frequency of occurrence of war events during follow-up was taken into consideration in the assessment of exposure. Hence, the total observation time for each subject was divided into several strata; each stratum represented the person-years contributed by the person at each level of exposure. All analyses were conducted for men and women separately.
Age-adjusted Mantel-Haenszel rate ratios and their 95 percent confidence intervals were estimated for each endpoint. The chi-square test was used to evaluate linear trends over categories of a cumulative score of war events. The score was constructed by summing over the total number of events (refer to the list in table 1). By using the statistical package Stata (release 4.0) (20), we constructed a series of multivariate Poisson regression models to adjust, initially, for classical risk factors and lifestyle covariates (age, hypertension, hypercholesterolemia, diabetes, smoking, and alcohol consumption) and, additionally, for marital, educational, and economic activity status. For exposures with important financial consequences (property losses and work-related problems), analyses were conducted stratified by education. Drawing on the results of earlier studies in Lebanon and the region, education was found to be a more sensitive discriminator of social class status than either occupation or income (21
). Parallel analyses were conducted in which war-related exposures were included in the models firstly as a set of dummy variables and secondly as continuous measures. Overall, results were in agreement. For brevity, the findings of only the latter analyses are presented in this paper.
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RESULTS |
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As figure 1 shows, about 32 percent of men and 37 percent of women were reported to have evaded all types of war events elicited in the interview schedule checklist. The remaining study subjects experienced at least one event, reaching a maximum of 10 for one male and 9 for two females. In all clusters, exposure of the subject to property losses was reported most frequently, particularly among men (39.6 percent) (table 2). Human losses and traumas were more likely to include injuries, whether they occurred to the study subject or to his or her family members, followed by "kidnappings." Table 3 presents the results of the age-adjusted models that were used to evaluate the relation between various clusters of war-related exposures and mortality. Whereas no significant association was found for men, women exposed to human losses had a significantly excess risk for both CVD (rate ratio (RR) = 3.37, 95 percent confidence interval (CI): 1.46, 7.79) and total mortality (RR = 2.28, 95 percent CI: 1.06, 4.90). Similar findings were observed when family members were exposed to human losses and traumas, although the magnitude of the effects was lower (CVD mortality: RR = 1.54, 95 percent CI: 1.21, 1.97; total mortality: RR = 1.31, 95 percent CI: 1.08, 1.59). Exposure to property losses, particularly when experienced directly by study subjects, carried a greater mortality risk for men and had only a weak association for women. For both men and women, work-related problems and displacement increased mortality risk. A significant positive trend in the rate ratios for both mortality endpoints was noted with an increase in the intensity of exposure to a cumulative number of war events (table 4).
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DISCUSSION |
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However, these findings have to be considered in light of the study's strengths and potential limitations. Social and cultural factors may have played a role in assessing causes of death based on verbal autopsies, but not in reporting the death event itself. Attempts to assess the validity of the verbal autopsies were hampered by the lack of other routine data sources in a country ravaged by the atrocities and chaos of war. Information on causes of death is essentially nonexistent in Lebanon. A research exercise conducted at the Vital Registration Department revealed that a considerable proportion of death certificates were missing information on cause of death (66 and 57 percent for 1984 and 1994, respectively). Until recently, government surveys were nonexistent, and population-based studies are limited by the substantial proportion of deaths classified as "missing" or "ill defined" (2243 percent) (19, 22
). Countries that lack reliable mortality data are increasingly adopting lay reporting schemes to ascertain cause-of-death patterns (23
). While our use of the broader system of CVD categorization may have minimized potential misclassification biases, it may also have increased the likelihood of false-positive CVD deaths.
Another potential limitation was recall of war events from proxy reporting. Although the validity of the information obtained could not be assessed, we examined the distribution of war events by demographic characteristics of the respondent and relationship to the study subject (data not shown). There was no clear, consistent trend in reporting by any of the informant characteristics. Nevertheless, during the years of conflict, there was a tendency to attribute ill health to the war. Hence, we cannot exclude the possibility that the propensity to recall a stressful event was more likely for subjects who died during the follow-up period than for survivors. Differential recall may have resulted in a more serious limitation regarding associations observed with all-cause than with CVD mortality, since neither respondents nor interviewers were informed about the major hypothesis of the study, and, for some cases (32 percent), data on causes of death were obtained on a different occasion and from an informant different from the person who initially provided information on war events. Importantly, associations overall were stronger for CVD than for all-cause mortality, with effects varying by gender, and there is no reason to think that subjects or interviewers would selectively recall or report certain types of events more frequently for one gender than the other.
Furthermore, although the study achieved a relatively high follow-up rate (87.7 percent), some source of bias may have been introduced if the study has disproportionately traced persons under stress who, at baseline, had a high risk for mortality. However, we found no difference by health characteristics at baseline or by proximity of the residence to a war zone area between those lost to follow-up and those traced successfully. Also, for those persons lost to follow-up compared with those traced, interviewers were more likely to find the buildings partially or completely demolished as a consequence of war atrocities in the neighborhood (12.8 vs. 2.3 percent). This finding means that loss to follow-up could lead to underestimation of the effect of war losses and damages on mortality.
We found that war-induced human losses were important predictors of mortality for women, but not men. This finding appears to be at odds with the majority of studies showing that bereavement carries a greater mortality risk for men (3, 24
). Although, in the literature, widowhood has been the key variable in assessing the impact of loss on mortality, our study examined losses in the extended family network, including immediate kin and not solely the spouse. Several studies have shown that men and women differ in how they utilize social and family networks (3
, 25
). Women seem more likely than men to seek support from a wider kinship and from social networks that include a higher proportion of family members (25
). Consequently, a crisis in the family network may take on a greater meaning for women than men.
In post hoc analyses to evaluate the relative contribution of individual exposures, rate ratios were highest for kidnappings in which the missing person was a relative of the woman study subject. Although it is difficult to give exact figures, and for many different reasons including ideological, political, and religious, innocent civilians commonly were missing during the Lebanese wars. The stress of the "disappearance" of close relatives does not decrease with the passage of time and hence was perceived as more overpowering than, for example, death.
Among men, losses associated with financial consequences, such as property damage and early retirement, took precedence over human losses in their impact on mortality, particularly for those men with lower levels of education. When the war flared up in 1975, the majority of the male study population (79 percent) were in the prime of their productive careers (aged 4060 years). During the war, many found themselves suddenly homeless (16.3 percent) or jobless (14.2 percent) because of either substantial damage or destruction or of squatters on their property. Some, driven by the fear of losing any further investments, remained inactive for many years. Essentially, they took an early or forced retirement (8.8 percent), which further increased the chronic financial strain and relative deprivation.
The literature is rich in studies suggesting that unemployment among men is associated with a high mortality risk (4, 26
27
28
) and that longer-term unemployment is more harmful than short-term joblessness (29
). On the other hand, retirement, as a normative transitional phase in life, often has been listed as negative in life events inventories and has been found to be associated with all-cause (30
) and CVD mortality (31
). Moreover, retirement has been rated as more stressful when it was unexpected or involuntary and among those who were of lower socioeconomic status (32
). The attenuated association among the socially advantaged counterparts in our study population might reflect the importance of increased economic infrastructure to compensate for damaged or lost property or possibly the presence of other coping mechanisms, such as more power and influence, to evacuate a squatter-occupied property with less expenditure.
The significant and consistent association observed between displacement and mortality, across all comparisons, supports results from previous studies suggesting that mortality among the displaced, particularly for those displaced in camps, is higher than for resident populations (33). Displacement may carry a greater risk presumably by bringing persons in contact with poor sanitation, overcrowding, poor nutrition and medical care, and other environmental predictors of adverse health outcomes. In our study, the location of displacement varied widely; quite often, there was a succession of relocations to different places. The need for frequent adaptations, the feeling of being a burden in others' homes, and the lack of social stability were all additional sources of incessant strain acting continuously over time.
The features of the present study design and the specificity of the study's objectives and hypothesis enabled us to make only very general comparisons. In earlier studies, most of which used a case-control design, stress developed from life events based on Holmes and Rahe's scale (34) was implicated as a risk factor for coronary heart disease (1
, 2
, 35
, 36
). By comparison, few prospective studies have been conducted that have produced conflicting results. Ruberman et al. (37
) demonstrated that a high degree of life stress and social isolation increases the risk of total and cardiac mortality in patients with myocardial infarction. In contrast, three prospective studies were unable to find a relation between life events scores and death from all causes or the incidence of heart disease (38
39
40
). Moore et al. indicated that information bias, because of the potential for frequent change in exposure during follow-up, remains a problem in prospective studies (40
).
The data from our study are unique in several aspects. Unlike earlier studies in which exposure measured once, only at the beginning of the follow-up period, was used to predict health outcomes several years later, our data offered one of the first opportunities to examine the impact of repeated events on mortality risk. Studies conducted at the cellular level present evidence that stressful stimuli produce patterns of neuroendocrine activation that are dependent on intensity and duration of the stressor, the interval between each episode of stress, and the number of presentations of the stressor (41). Our data also indicate that it is important to examine discrete elements of markers of stress in relation to health outcomes, and they reinforce (17
) the need for a gender-specific approach to research on this topic.
There is increasing conviction that war experiences and mass traumas are likely to lead to persistently elevated psychological symptomatology that may linger many years after exposure (42). However, there remains a paucity of research addressing the broad and long-term impact of war on physical health. In a recent study, Armenian et al. established that morbidity from heart disease and other chronic conditions increased 4 years after earthquake-related damages and losses and called for focused preventive strategies following disasters (43
). In Bosnia and Herzegovina, the long-lasting bombing increased significantly the number of acute coronary admissions to a regional hospital during the war in comparison to the years before (44
).
Wars and political violence continue to spread in many regions of the world and have recently appeared in more developed countries. Most relief agencies provide short-term temporary intervention measures and cease their activities once reconciliation in the country has been achieved. A study of war-related injuries during the 1996 attack on south Lebanon (Grapes of Wrath) documented the poor fit between acute health care interventions and the diverse and chronic needs of people with injuries and of their families (45). Governments and international donor agencies, as well as researchers, should consider that the impact of wars and mass disasters may not be restricted to the catastrophic event and solely to the victims involved. Because of disruptions to the social and economic infrastructure, those not directly affected may also be subject to long-term and chronic adverse health outcomes.
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ACKNOWLEDGMENTS |
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The authors are grateful to the researchers who conducted the 1983 Beirut survey and made part of their data available for the present follow-up study. They thank Dr. Michael Hills for his statistical contribution, Dr. Alex Kalache for his advice during the preliminary stages of the study, and Dr. Robin Heath for her critical reading of an earlier version of the manuscript.
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NOTES |
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REFERENCES |
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