Non-participation and attrition in a longitudinal study of civilians exposed to the January 2015 terrorist attacks in Paris, France

Abstract

Background: Non-participation and attrition are rarely studied despite being important methodological issues when performing post-disaster studies. A longitudinal survey of civilians exposed to the January 2015 terrorist attacks in Paris, France, was conducted 6 (Wave 1) and 18 months (Wave 2) after the attacks. We described nonparticipation in Wave 1 and determined the factors associated with attrition in Wave 2. Methods: Multivariate logistic regression models were used to compare participants in both waves with those who participated in the first wave only. Analyses were performed taking the following factors into account: sociodemographic characteristics, exposure to terror, peri-traumatic reactions, psychological support, perceived social support, impact on work, social and family life, and mental health disorders. Characteristics of new participants in Wave 2 were compared with participants in both waves using a chi-square test. Results: Of the 390 persons who were eligible to participate in the survey, 190 participated in Wave 1 (participation rate: 49%). The most frequently reported reason for non-participation was to avoid being reminded of the painful event (32%, n = 34/105). In Wave 2, 67 were lost to follow-up, 141 people participated, of whom 123 participated in Wave 1 (re-participation rate: 65%) and 18 were new. Attrition in Wave 2 was associated with socio-demographic characteristics (age, French origin) and location during the attacks, but not with terror exposure or mental health disorders. Compared with those who participated in both waves, new participants declared less social and psychological support since the attacks. Conclusions: Attrition at 6 months was not associated with exposure to terror or mental health disorders, which indicates that any bias in future analyses on IMPACTS on mental health outcomes will be limited. Our findings suggest the importance of adapting similar surveys for people of foreign origin and of improving strategies to avoid attrition of younger people, for example by using social media, peers, and the educational environment. The present study also revealed that a high level of exposure to terror and a lack of social and psychological support after a terrorist event could impede individuals' participation in similar surveys in the short term.

Use of mental health supports by civilians exposed to the November 2015 terrorist attacks in Paris

“…In the Utøya cohort study, those who did not participate in the first wave were more likely to have more post-traumatic stress reactions during the second wave of the study than participants in the first wave [ 48 ]. This finding was not echoed in a French open cohort study which followed people directly threatened in the January 2015 terrorist attacks in Paris [ 49 ]. It is also possible that people who were suffering less at the time of the ESPA 13 November survey may have felt less motivated to participate or indeed that their participation was less legitimate than that of others.…”

Mental health impact among hospital staff in the aftermath of the Nice 2016 terror attack: the ECHOS de Nice study

“…This reflects a self-selection bias, in which individuals are more likely to respond to items which interest them or which are directly related to their own situation [ 59 ]; however, the most members of the hospital staff were probably unexposed. Conversely, those most exposed may have refused to complete the questionnaire to avoid recalling painful memories [ 60 ], while studies insist on the need to improve participation to identify individuals with the highest morbidity rate [ 61 ]. Moreover, staff members who might have left the institutions after the attacks were not able to take part in the survey and experiencing this event may have increased staff turnover and resulted in staff leaving the institution, so that the prevalence rates are likely to be underestimated.…”

PTSD in French Adolescent Victims Following the London Attack in March 2017: Data From the First Step of the AVAL Study

“…The Nice study (39), like ours, highlighted and encouraged the follow-up of adolescents, especially if they are vulnerable, in a standardized manner, to ensure the screening and treatment of all young people. Cohort studies conducted following other terrorist attacks, such as 9/11, the Madrid, 2004 car bombings, the 2011 Oslo/Utoya massacre and Paris, 2015, showed participation rates ranging from 40 to 70% in the first wave, and 50 to 75% in the second wave (40,41). Although these attacks vary considerably in their details, the participation rates are similar, and may be improved in younger people via the utilization of social media, peers, and educational environments, as noted by Vuillermoz et al following the Paris, 2015 attacks (41).…”

“…Cohort studies conducted following other terrorist attacks, such as 9/11, the Madrid, 2004 car bombings, the 2011 Oslo/Utoya massacre and Paris, 2015, showed participation rates ranging from 40 to 70% in the first wave, and 50 to 75% in the second wave (40,41). Although these attacks vary considerably in their details, the participation rates are similar, and may be improved in younger people via the utilization of social media, peers, and educational environments, as noted by Vuillermoz et al following the Paris, 2015 attacks (41). The higher level (73.6 %) of participation in the current study could be explained by various details: (1) the small size of the total target population which allowed us to identify each teenager present in the event;…”