1. Introduction

According to general population studies, every fifth person experiences a natural disaster during his/her life [1,2]. Psychological consequences of disasters have been extensively investigated, with post-traumatic stress disorder (PTSD) being the most frequently studied condition followed by depression and anxiety [3]. A substantial body of research has investigated factors associated with psychopathologies in the aftermath of disasters [4–6]. Fewer studies have explored long-term effects of disasters on survivors’ mental health and have found that disasters could lead to enduring psychological distress [7,8].

There are very few studies on the longer-term influence of disasters on victims’ quality of life showing that long-lasting psychological and environmental consequences of disasters could have an adverse impact on survivors’ quality of life [9–11]. Considerable evidence suggests poorer general health outcomes among survivors of disasters and traumatized subjects in terms of increased physical morbidity and mortality several years after the trauma [11–15]. Nevertheless, studies of self-rated health (SRH) among disaster victims many years after the exposure are very rare [16,17].

On December 7, 1988, a devastating earthquake struck the northern regions of Armenia and left half a million people – one-sixth of the country’s population – without shelter. Over 100,000 people were injured and 25,000 died. Rehabilitation after the earthquake was delayed because its timing coincided with a difficult transition of the country from the soviet system to a market economy aggravated by a number of cataclysms, including an economic blockade, an energy crisis and a war [18]. Thus, survivors had to cope with very difficult conditions for many years following the disaster. In 1990, a large-scale cohort study was initiated in the earthquake zone to prospectively measure the health outcomes of survivors [19]. The exceptional opportunity provided by this cohort study was used to explore the association between factors assessed at the baseline waves of the study in the early 1990s and SRH of the earthquake survivors over 23 years after the exposure.

SRH was used in this long-term follow-up study as a general measure of physical and mental health status due to its proven strong correlation with objective measures of health status and subsequent mortality [20–25]. This measure was considered particularly valuable for the study purposes as it reflects not only measurable aspects of health, but also subjective feelings and future expectations of well-being [26,27]. It presumably covers also medically unexplained symptoms, a phenomenon frequently detected among disaster survivors [13,28].

The prevalence and predictors of poor SRH have been extensively investigated in different countries and population groups, as this outcome measure is frequently used in health disparities research [29–31]. Two prior cross-sectional studies of SRH conducted among the general population in Armenia found high rates of perceived poor health and an independent relation between health and older age, poverty, lower education, unemployment, depression, and lack of social support [32,33]. The aim of this prospective study was to investigate the prevalence of poor SRH in a long-term cohort of survivors of the 1988 earthquake, to find out whether the severity of the earthquake exposure was related to this outcome after 23 years, and to identify long- and short-term determinants of poor SRH in this disadvantaged population group.

2. Methods

3. Results

Seven hundred nineteen participants (99.2% of the total sample of 725) responded to the item on SRH. The mean age of the respondents was 58.4 years (SD 12.1). Over two-thirds of them were women (Table 1). The majority had complete secondary and a quarter university or higher education. More than half of the participants were unemployed or unable to work, and 58.0% reported low affordability of healthcare. Over half of the participants (56.5%) perceived their health in the last 30 days as “fair”, one-fourth (24.7%) as good and 18.8% as poor.

Those who reported poor health were older, poorer, and less educated. Neither baseline, nor current smoking or drinking practices were significantly related to SRH during bivariate comparisons. Among the health behavioral variables, only those reflecting the level of physical activity, both baseline and current, were significantly associated with perceived health status (Table 1).

All the current psychosocial variables (memory, dignity, social support, and number of stressful life events) were highly related to SRH in bivariate comparisons. The same was true for all the current health status variables (QOL, multi-morbidity, depression, anxiety, and PTSD). Baseline multi-morbidity and baseline BMI were also significantly associated with SRH, while baseline psychopathology was not related to it. Similarly, no relation was found between the earthquake exposure variables and survivors’ SRH 23 years after the exposure.

In the multivariate logistic regression analysis, the association between SRH and its correlates – current physical and mental health status variables – remained strong after controlling for all the remaining significant variables (Table 2). In the model controlled for all significant variables, current poor QOL and current multi-morbidity increased the likelihood of poor rating of own health over five times, and current depression – over four times, mediating the effect of current anxiety and PTSD on SRH.

The final fitted logistic regression model of determinants of poor SRH identified nine significant variables (Table 3). Three of these were baseline variables, information on which was collected prospectively over two decades ago – BMI, multi-morbidity, and regular participation in sports. When controlling for the remaining significant variables, baseline multi-morbidity increased the chance of current poor SRH almost twice. Each one point increase in the baseline BMI (kg/m²) was associated with 11.0% higher chance of current poor SRH. Regular participation in sports in the early 1990s decreased the chance of poor SRH in 2012 more than two times.

The next two baseline determinants of SRH were perceived living standards during the post-earthquake decade and the number of reported stressful negative life events. Both were strong predictors of SRH. Poor living standards during the post-earthquake decade increased the chance of current poor SRH 2.3 times. Each additional stressful life event was associated with 15.0% higher chance of poor SRH in the final model.

Of the current variables, social support, SES score, employment and household size were among independent determinants of SRH. Current good social support and current employment both decreased the likelihood of poor SRH over two times. An increase of the household size by one member was associated with a 16.0% higher chance of poor SRH. Each unit increase in the SES score decreased the chance of poor SRH by 8.0%. Although marginally significant, low dignity was also associated with a considerably higher chance of poor SRH in the final model. The model achieved good fit indices (Table 3). The highest value for VIF detected in this model did not exceed 1.3, indicating no issue of collinearity [49]. No interactions between the studied variables were found.

Adjusted relative risks were calculated for the variables reflecting baseline characteristics, using the advantage the cohort study design provides. Three of these variables (except baseline multi-morbidity and baseline regular participation in sports) – baseline BMI, perceived living standards during the post-earthquake decade, and number of stressful life events – remained significant predictors of SRH in the final model (Table 4). When controlling for the remaining significant variables, the risk of poor SRH was 58% higher for those who reported poor living standards during the post-earthquake decade as compared with those who reported average/good living standards during that period. On average, the risk of poor SRH increased independently by 5% for each additional unit of the baseline BMI (kg/m²) and by 10% for each additional stressful life event experienced by a respondent.

4. Discussion

The prevalence of poor SRH in this long-term cohort of earthquake survivors was rather high (18.8%) with no significant between-gender differences (19.3% among women and 17.8% among men). However, the proportion of those rating their health as less than good (fair/poor) was significantly higher among women (78.3%) than among men (68.9%), which is consistent with other reports [50–52]. Although higher when compared with western European countries and the United States [53,54], the observed rates of poor SRH in this study were comparable to the rates previously reported in Armenia [32,33] and other former Soviet Union countries [55,56]. The strong independent relation of SRH with the correlate measures of physical and mental health in this study affirmed the use of this measure as a valid marker of general health status of the survivors.

This cohort study was unique, as it provided a rare opportunity to explore the relation between current SRH and baseline psychosocial, earthquake exposure, lifestyle, and other factors, the data on which were collected prospectively over two decades ago independently from the study outcome. Among the many prospectively-obtained baseline variables, three independent long-term predictors of SRH were identified, all related to the survivors’ baseline health status and/or lifestyle: baseline BMI, multi-morbidity, and regular participation in sports. All these factors are well-known determinants of SRH [57–62]. However, their persistent influence on perceived health status even after 23 years is an important finding of this study, clearly demonstrating the role of healthy lifestyle for future optimal health.

Neither earthquake exposure variables, nor baseline PTSD were associated with SRH 23 years after the event. According to a meta-analysis investigating factors influencing the relationship between disasters and their mental health consequences, the time elapsed since the disaster was inversely related to its effect size [63]. As SRH covers both physical and mental components of health, this inverse relation could possibly explain the lack of association between earthquake exposure and perceived health status 23 years after the disaster among this study sample.

Unlike baseline psychopathology, current depression, anxiety and PTSD were strongly related to SRH, acting as its correlates rather than determinants and demonstrating the ability of SRH to also capture mental aspects of overall health. In the model controlled for all significant variables, only depression remained a strong predictor of SRH, mediating the relation between the latter and the remaining two psychopathologies: anxiety and PTSD. This finding suggests a high shared variability between these common mental disorders among disaster survivors, a finding well supported in the literature [64–66].

This study identified a strong independent relation between SRH and the number of experienced stressful negative life events, with each additional such event increasing the risk of perceived poor health by 10%. This finding was consistent with the results of other studies reporting a significant independent association between stressful life events and both poor SRH [17,67] and adverse mental [5,68] and physical health outcomes [69,70].

Current socio-economic status score and living standards during the post-earthquake decade were among the independent predictors of SRH in this study. Perceived poor living standards during the first 10 years after the earthquake were among the strongest predictors of poor SRH, increasing the risk of the latter by 58%. These findings provided evidence supporting the role of socioeconomic inequities in determining SRH of disaster survivors and were consistent with other studies among populations exposed to disasters [9–11,71]. Poor living standards during early post-disaster period, when victims are especially vulnerable, were particularly detrimental for further SRH.

Respondent’s current family size and employment status were also among the independent determinants of SRH. Living in larger families and being unemployed were characteristics associated with an increased likelihood of poor SRH. Although these factors mainly reflect a respondent’s socioeconomic status, their association with SRH remained significant when controlling for current socioeconomic status scores, indicating either limited versatility of the latter or some other pathway of their relation to the outcome, for instance, a better sense of perceived control and coherence that employment possibly provides. Also, the data on these variables were collected during the follow-up study simultaneously with the outcome and a reverse causation could have a place, when poor health status resulted in unemployment or a necessity to live in an extended family.

Current good social support was a strong protective factor for SRH in this study. The close relation between social resource loss and adverse health consequences of disasters is well documented in the literature [3]. Disruption of social networks and lack of social support were found to be important risk factors for psychological distress among trauma-exposed populations [5,7]. The significant independent relation between social support and SRH among disaster survivors is also documented [72]. However, the direction of the association between social support and SRH is difficult to establish in the current study, as a reciprocal relation between the two is possible.

Although marginally significant in the fitted model, perceived low dignity was also associated with poor SRH among long-term survivors of the earthquake. This is an interesting finding in the light of studies demonstrating the importance of self-efficacy, perceived control and optimism to avoid adverse health consequences of disasters [3]. This finding emphasizes the importance of provision of psychological support to disaster victims.

The main limitation of this study was that SRH was not measured during the baseline phases of the cohort study. Because of this, it was not possible to investigate the changes in survivors’ perceived health status over the study period. Lack of generalizability of these findings to other population groups with different experiences and socio-cultural profiles could be another limitation of the study. This study was also limited in revealing the direction of association between poor SRH and its current predictors, as the data on these variables were collected at the same time with the outcome during the follow-up assessment in 2012. Data on two predictors of SRH reflecting prior experiences (stressful negative life events and perceived living standards during the post-earthquake decade) were collected retrospectively, which could be subject to recall bias. However, the consistency of these findings with relevant literature reassures us in the validity of the identified associations.

This study was unique as it followed earthquake survivors for over two decades. It was able to investigate the influence of a number of prospectively obtained baseline variables on survivors’ current SRH and to reveal associations between these and the outcome free from any bias related to recall or direction of association. The study demonstrated that the influence of earthquake exposure on survivors’ health diminished over time. However, it found other factors that had life-long influences on survivors’ SRH status. Cumulative lifetime stress, lifestyle factors including the level of physical activity, poor living standards, and baseline multi-morbidity were among these factors. While some of the identified risk factors are not easily modifiable, others like lifestyle factors and the levels of material, social and psychological support to survivors are reasonably modifiable. Hence, timely efforts to improve these factors among disaster victims could have a long-lasting impact on their health.

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Conflict of interest

H.K. Armenian is an associate editor at the Journal of Epidemiology and Global Health.

Acknowledgments

The first three phases of the study were supported by a grant from the Armenian Relief Society, Inc., Watertown, MA 02172 USA, and by the Ministry of Health of the Republic of Armenia. The Turpanjian Family Educational Foundation financed the recent 4th phase of this study.