PRESOLRE: study protocol for a primary school-based, cluster randomised controlled trial of three sun exposure risk prevention strategies on Reunion Island.

INTRODUCTION: Reunion Island, a French overseas department, is located in the southern hemisphere, close to the Capricorn tropic. This island has a multicultural and multiethnic population of 860 000 inhabitants, a quarter of whom are at high risk of developing skin cancer due to intense ultraviolet radiation. Melanoma is responsible for the majority of skin cancer deaths. The early prevention of melanoma is based on sun protection in childhood, but French regulations are not adapted to the environmental conditions of this tropical region.The main objective of our study is to evaluate the effectiveness of three sun protection programs conducted in Reunionese primary schools through a pupil knowledge questionnaire. METHODS AND ANALYSIS: PRESOLRE is an interventional, open-label, cluster-randomised controlled trial, in four parallel arms, that is being conducted throughout 2022-2023 on Reunion Island. The trial design assumes an escalation interventional effect using: first, a control arm without proposed intervention (arm 1); second, an arm whose classes are encouraged to use the validated educational programme 'Living With the Sun' (LWS) (arm 2); third, an arm whose classes are encouraged to use both 'LWS' combined with 'Mission Soleil Réunion's sun protection awareness programme (arm 3); fourth, an arm benefiting from an intervention similar to arm 3, combined with the distribution of hats, sunglasses and sun creams (arm 4). In all, 1780 pupils from 18 classes of 20 pupils, on average, will be included. Randomisation applies to the classes of pupils (so defined as clusters). The primary outcome is based on the proportion of correct answers to the knowledge questions after the awareness programme, compared between the four arms using a linear mixed model with random intercept. ETHICS AND DISSEMINATION: The study obtained ethics approval in 2022 (ID: 2022-A00350-43). Results will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05367180.

Attrition and social vulnerability during 2-year-long structured care in type 2 diabetes, the ERMIES randomized controlled trial.

BACKGROUND: Diabetes self-management education is exposed to attrition from services and structured ambulatory care. However, knowledge about factors related to attrition in educational programs remains limited. The context of social vulnerability due to low income may interfere. The aim of this study was to identify the sociodemographic, clinical, psychometric, and lifestyle factors associated with attrition from the ERMIES multicentre randomized parallel controlled trial (RCT) that was interrupted due to the combination of both slow inclusion and high attrition. METHODS: The ERMIES trial was performed from 2011 to 2016 on Reunion Island, which is characterized by a multicultural population and high social vulnerability. The original objective of the RCT was to test the efficacy of a2-year structured group self-management education in improving blood glucose in adult patients with nonrecent, insufficiently controlled type 2 diabetes. One hundred participants were randomized to intensive educational intervention maintained over two years (n = 51) versus only initial education (n = 49). Randomization was stratified on two factors: centres (five strata) and antidiabetic treatment (two strata: insulin-treated or not). Sociodemographic, clinical, health-care access and pathway, psychometric and lifestyle characteristics data were collected at baseline and used to assess determinants of attrition in a particular social context and vulnerability. Attrition and retention rates were measured at each visit during the study. Multiple correspondence analysis and Cox regression were performed to identify variables associated with attrition. RESULTS: The global attrition rate was 26% during the study, with no significant difference between the two arms of randomization (9 dropouts out of 51 patients in the intervention group and 17 out of 49 in the control group). Male gender, multiperson household, low household incomes (< 800 euros), probable depression and history of hospitalization or medical leave at inclusion were associated with a higher risk of attrition from the study in multivariate regression. CONCLUSIONS: Social context, vulnerability, and health care history were related to attrition in this 2-year longitudinal comparative study of structured care. Considering these potential determinants and biases is of importance in scaling up interventions aimed at the optimization of long-term care in type 2 diabetes mellitus. TRIAL REGISTRATION: ID_RCB number: 2011-A00046-35, Clinicaltrials.gov number: NCT01425866 (Registration date: 30/08/2011). SOURCE OF FUNDING: Ministry of Health, France.

Health Impacts of the COVID-19 Lockdown Measure in a Low Socio-Economic Setting: A Cross-Sectional Study on Reunion Island.

In March 2020, the French government implemented nation-wide measures to reduce social contact and slow the progression of the emerging coronavirus responsible for COVID-19, the most significant being a complete home lockdown that lasted 8 weeks. Reunion Island is a French overseas department marked by large social inequalities. We draw the hypothesis that distancing and lockdown measures may have contributed to an increase in the social inequalities in health (SIH) on Reunion Island. The aim of our study was to describe the SIH during lockdown in the Reunionese population. We implemented a cross-sectional telephone survey conducted between 13 May and 22 July 2020, using a retrospective data collection on the lockdown period. A total of 892 adult participants (≥18 years) were recruited in the 114 large Reunionese neighborhoods using the quota method within the national "White Pages" telephone directory. Degraded psychological states, an increase in addictive behaviors, difficulties in accessing food, a decrease in physical activity, delayed medical appointments, violence against women, and health problems in children were driven by the socio-economic characteristics of the population, most often to the disadvantage of social groups exposed to poor living conditions. These results suggest that the COVID-19 lockdown contributed to an increase in SIH.

Usefulness of Home Screening for Promoting Awareness of Impaired Glycemic Status and Utilization of Primary Care in a Low Socio-Economic Setting: A Follow-Up Study in Reunion Island.

BACKGROUND: Low socio-economic settings are characterized by high prevalence of diabetes and difficulty in accessing healthcare. In these contexts, proximity health services could improve healthcare access for diabetes prevention. Our primary objective was to evaluate the usefulness of home screening for promoting awareness of impaired glycemic status and utilization of primary care among adults aged 18-79 in a low socio-economic setting. METHODS: This follow-up study was conducted in 2015-2016 in Reunion Island, a French overseas department in the Indian Ocean. Enrollment and screening occurred on the same day at the home of participants (N=907). Impaired glycemic status was defined as [glycated hemoglobin (HbA1c) ≥5.7%] OR [fasting capillary blood glucose (FCBG) ≥1.10 g/L] OR [HbA1c=5.5-5.6% and FCBG=1.00-1.09 g/L]. Medical, socio-cultural, and socio-economic characteristics were collected via a face-to-face questionnaire. A one-month telephone follow-up survey was conducted to determine whether participants had consulted a general practitioner (GP) for confirmation of screening results. A multinomial polytomous logistic regression model was used to identify factors independently associated with non-use of GP consultation for confirmation of screening results and nonresponse to the telephone follow-up survey. RESULTS: Prevalence of glycemic abnormalities was 46.0% (95% CI = 42.7-49.2%). Among participants with impaired glycemic status (N=417), 77.7% (95% CI=73.7-81.7%) consulted a GP for confirmation of screening results, 12.5% (95% CI=9.3-15.6%) did not, and 9.8% failed to respond to the follow-up survey. Factors independently associated with non-use of GP consultation for confirmation of screening results were self-reported unwillingness to consult a GP (adjusted odds ratio [OR]: 4.86, 95% CI=1.70-13.84), usual GP consultation frequency of less than once a year (adjusted OR: 4.13, 95% CI=1.56-10.97), and age 18-39 years (adjusted OR: 3.09, 95% CI=1.46-6.57). CONCLUSION: Home screening for glycemic abnormalities is a useful proximity health service for diabetes prevention in low socio-economic settings. Further efforts, including health literacy interventions, are needed to increase utilization of primary care.

Sexual dimorphism in the association between gestational diabetes mellitus and overweight in offspring at 5-7 years: The OBEGEST cohort study.

Evidence from literature is mixed regarding a possible association of maternal gestational diabetes mellitus (GDM) and overweight in the offspring. Sexual dimorphism, or sex disparities in the pathogenesis linking GDM exposure to overweight, could be at play. The objective of this study was to investigate the association between GDM and child overweight at 5-7 years. Six hundred pairs (1:1) of Reunionese liveborn singletons selected from a hospital-based birth registry, matched for sex, gestational age, and birth period, underwent a prospective in-home follow-up and were analyzed with respect to their exposure to GDM. The primary outcome was child overweight at 5-7 years, as defined by the International Obesity Task Force. The association between GDM exposure and child overweight was estimated by the odds ratio (OR) using conditional logistic regression models. For the subset of children exposed to GDM with available maternal glycemic data, we analyzed the relationship between maternal glycemic levels during pregnancy and child body mass index (BMI) at 5-7 years with a linear regression model. In light of the significant interaction between sex and GDM, all statistical analyses were then stratified by sex. After controlling for pre-pregnancy BMI and maternal sociodemographic characteristics, the risk of overweight increased with exposure to GDM for boys (adjusted OR: 2.34; 95% confidence interval = 1.26-4.34, P = 0.007) but not for girls (adjusted OR: 0.56; 95%CI = 0.28-1.10, P = 0.093). Consistent with this, the linear increase of boys' BMI at 5-7 years with maternal blood glucose levels during pregnancy, in the exposed group, displayed a dose-response relationship. Our findings indicate that exposure to GDM is a risk factor for childhood overweight in boys but not in girls, which adds to the growing body of evidence suggesting greater sensitivity of male offspring to intrauterine hyperglycemia.

Rheumatic manifestations associated with Chikungunya virus infection: A study of 307 patients with 32-month follow-up (RHUMATOCHIK study).

OBJECTIVES: In the wake of the Chikungunya epidemic which struck Reunion Island in 2005 and 2006, we conducted a prospective, multicentre study (RHUMATOCHIK) whose main objective was analyse the characteristics and progression of rheumatic manifestations in patients with post-Chikungunya joint pain. METHODS: A cohort of 307 consecutively included patients underwent rheumatological examinations for pain secondary to Chikungunya virus infection. The long-term evaluation was conducted by telephone survey 1 and 2 years after the onset of the viral infection. RESULTS: At inclusion, mean age was 54 years (24-87) and 83.1% of the patients were female. Chronic joint pain was associated with synovitis in 64.2% of the patients, affecting primarily the wrists, the proximal interphalangeal joints of the fingers, and the ankles. Attempts to detect the viral genome in joint fluid (10 patients) and synovial tissue (6 patients) using the RT-PCR technique were repeatedly unsuccessful. With a mean follow-up of 32 months, joint pain persisted in 83.1% of the patients. Functional impairment, however, was moderate, with a HAQ score of 0.44±0.5. CONCLUSION: Chikungunya virus infection is frequently the cause of joint manifestations that can persist for several months, or even several years. In some cases, the clinical symptoms closely resemble those usually associated with rheumatoid arthritis. Further studies are necessary to improve the therapeutic management of these patients.

[To analyse the transferability of an intervention : applying the functions/implementation/context model on a diabetes prevention programme]. / Analyser la transférabilité d'une intervention : application du modèle fonctions clés/implémentation/contexte à un programme de prévention du diabète.

INTRODUCTION: A type 2 diabetes primary prevention programme that was shown to be feasible and effective in 2003 was transferred to another vulnerable district of Reunion Island in 2004, but its short-term effectiveness could not be reproduced. Based on this example, this article analyses whether the key functions/implementation/context model can be useful to : 1- more accurately describe an evaluated intervention ; and 2- identify the factors involved in the transferability of this intervention. METHODS: The causality model of the initial programme is described. We then identified the key functions (or theoretical processes) of this initial programme, implementation of these functions, and the context in which the intervention took place. Transfer was analysed by focusing on the differences between the initial programme and the transferred programme in terms of key functions, implementation and context. RESULTS: The causality model involves individual, meso-social, and environmental health determinants. Our analysis of programme transfer highlights differences in : key functions (two key functions dropped, one key function added, one key function modified), implementation (failure to implement, loss/improvement of quality), and context (population and socioeconomic level of the district concerned). CONCLUSION: This work supports the hypothesis that the key functions/implementation/context model can be useful to improve the description of an intervention, and analyse the factors involved in its transferability.

Long-Term Effectiveness of a Lifestyle Intervention for the Primary Prevention of Type 2 Diabetes in a Low Socio-Economic Community--An Intervention Follow-Up Study on Reunion Island.

In type 2 diabetes (T2D) prevention research, evidence for maintenance of risk factor reduction after three years of follow-up is needed. The objective of this study was to evaluate the long-term effectiveness of a combined lifestyle intervention aiming at controlling body weight (BW) and waist circumference (WC) in non-diabetic, overweight/obese adults living in a low socio-economic community. On Reunion Island, 445 adults living in deprived areas, aged 18-40 and at high-risk for T2D, were included in an intervention versus control trial for primary prevention (2001-2002). The intervention promoted a healthy diet and moderate regular physical activity, through actions strengthening individuals or community and improving living conditions. The control group received a one-shot medical information and nutritional advices. After the end of the trial (2003), 259 of the subjects participated in a follow-up study (2010-2011). The outcomes were the nine-year changes from baseline in BW, body mass index (BMI) and WC measurements, separately. Statistical analyses were performed on an intention-to-treat basis, using available and imputed datasets. At inclusion, T2D risk factors were prevalent: family history of diabetes in first-degree relatives (42%), women with a personal history of gestational diabetes (11%), total obesity (43%, median BMI 29.1 kg/m²) and central obesity (71%). At follow-up, the adjusted effect on imputed dataset was significant for WC -2.4 cm (95% confidence interval: -4.7 to -0.0 cm, p = 0.046), non-significant for BW -2.2 kg (-4.6 to +0.2 kg, p = 0.073) and BMI -0.81 kg/m² (-1.69 to +0.08 kg/m², p = 0.074). A specific long-term effect was the increased likelihood of reduction in adiposity: BW loss, BMI reduction, and WC reduction were more frequent in the intervention group. In the context of low socio-economic communities, our data support the assumption of long-term effect of lifestyle interventions targeting total obesity and central obesity two major drivers of T2D.

Individualized Exercise Training at Maximal Fat Oxidation Combined with Fruit and Vegetable-Rich Diet in Overweight or Obese Women: The LIPOXmax-Réunion Randomized Controlled Trial.

OBJECTIVES: Lifestyle combined interventions are a key strategy for preventing type-2 diabetes (T2DM) in overweight or obese subjects. In this framework, LIPOXmax individualized training, based on maximal fat oxidation [MFO], may be a promising intervention to promote fat mass (FM) reduction and prevent T2DM. Our primary objective was to compare three training programs of physical activity combined with a fruit- and vegetable-rich diet in reducing FM in overweight or obese women. DESIGN AND SETTING: A five months non-blinded randomized controlled trial (RCT) with three parallel groups in La Réunion Island, a region where metabolic diseases are highly prevalent. SUBJECTS: One hundred and thirty-six non-diabetic obese (body mass index [BMI]: 27-40 kg/m2) young women (aged 20-40) were randomized (G1: MFO intensity; G2: 60% of VO2-peak intensity; G3: free moderate-intensity at-home exercise following good physical practices). OUTCOMES: Anthropometry (BMI, bodyweight, FM, fat-free mass), glucose (fasting plasma glucose, insulin, HOMA-IR) and lipid (cholesterol and triglycerides) profiles, and MFO values were measured at month-0, month-3 and month-5. RESULTS: At month-5, among 109 women assessed on body composition, the three groups exhibited a significant FM reduction over time (G1: -4.1±0.54 kg; G2: -4.7±0.53 kg; G3: -3.5±0.78 kg, p<0.001, respectively) without inter-group differences (p = 0.135). All groups exhibited significant reductions in insulin levels or HOMA-IR index, and higher MFO values over time (p<0.001, respectively) but glucose control improvement was higher in G1 than in G3 while MFO values were higher in G1 than in G2 and G3. Changes in other outcome measures and inter-group differences were not significant. CONCLUSION: In our RCT the LIPOXmax intervention did not show a superiority in reducing FM in overweight or obese women but is associated with higher MFO and better glucose control improvements. Other studies are required before proposing LIPOXmax training for the prevention of T2DM in overweight or obese women. TRIAL REGISTRATION: ClincialTrials.gov NCT01464073.

The influenza A (H1N1) pandemic in Reunion Island: knowledge, perceived risk and precautionary behaviour.

BACKGROUND: The effectiveness of preventive measures depends on prevailing attitudes and mindsets within a population. Perceived risk is central to a shift in mindset and behaviour. The present study aims to investigate the perceived severity, vulnerability and precautionary behaviour adopted in response to the influenza A (H1N1) epidemic that broke out in 2009 on Reunion Island (Indian Ocean). As no H1N1 vaccination was available at the time, non-medical interventions appeared of crucial importance to the control of the epidemic. METHODS: A cross sectional survey was conducted in Reunion Island between November 2009 and April 2010 within 2 months of the passage of the influenza A (H1N1) epidemic wave. Individual contacts representing 725 households (one contact per household) were interviewed by telephone using validated questionnaires on perceived risks. Mean scores were calculated for perceived severity, vulnerability, efficacy of preventive measures and precautionary behaviour. Univariate analysis was applied to identify preventive measures and attitudes and multivariate analysis was used to study the determinants of precautionary behaviour. RESULTS: More than 95% of contacted persons accepted to participate to the survey. Eighty seven percent of respondents believed that prevention was possible. On average, three out of six preventive measures were deemed effective. Spontaneously, 57% of the respondents reported that they took one or more preventive measures. This percentage increased to 87% after the interviewer detailed possible precautions one by one. The main precautions taken were frequent hand washing (59%) and avoidance of crowded places (34%). In multivariate logistic regression analysis the following factors were significantly associated with taking one or more preventive measures: young age, previous vaccination against seasonal influenza, having had seasonal influenza in the last five years, effectiveness of the preventive measures taken and low standards of education. CONCLUSION: Inhabitants of Reunion Island have expressed a preventive approach adapted to the realities of the H1N1 pandemic, a feature that likely reflects some preparedness gained after the large and severe chikungunya epidemic that hit the island in 2006. The degree of severity was well assessed despite the initial alarmist messages disseminated by national and international media. Precautions that were undertaken matched the degree of severity of the epidemic and the recommendations issued by health authorities. Further qualitative studies are needed to help adapting public messages to the social and cultural realities of diverse communities and to prevent misconceptions.

Predictors of Chikungunya rheumatism: a prognostic survey ancillary to the TELECHIK cohort study.

INTRODUCTION: Long-lasting relapsing or lingering rheumatic musculoskeletal pain (RMSP) is the hallmark of Chikungunya virus (CHIKV) rheumatism (CHIK-R). Little is known on their prognostic factors. The aim of this prognostic study was to search the determinants of lingering or relapsing RMSP indicative of CHIK-R. METHODS: Three hundred and forty-six infected adults (age≥15 years) having declared RMSP at disease onset were extracted from the TELECHIK cohort study, Reunion island, and analyzed using a multinomial logistic regression model. We also searched for the predictors of CHIKV-specific IgG titres, assessed at the time of a serosurvey, using multiple linear regression analysis. RESULTS: Of these, 111 (32.1%) reported relapsing RMSP, 150 (43.3%) lingering RMSP, and 85 (24.6%) had fully recovered (reference group) on average two years after acute infection. In the final model controlling for gender, the determinants of relapsing RMSP were the age 45-59 years (adjusted OR: 2.9, 95% CI: 1.0, 8.6) or greater or equal than 60 years (adjusted OR: 10.4, 95% CI: 3.5, 31.1), severe rheumatic involvement (fever, at least six joints plus four other symptoms) at presentation (adjusted OR: 3.6, 95% CI: 1.5, 8.2), and CHIKV-specific IgG titres (adjusted OR: 3.2, 95% CI: 1.8, 5.5, per one unit increase). Prognostic factors for lingering RMSP were age 45-59 years (adjusted OR: 6.4, 95% CI: 1.8, 22.1) or greater or equal than 60 years (adjusted OR: 22.3, 95% CI: 6.3, 78.1), severe initial rheumatic involvement (adjusted OR: 5.5, 95% CI: 2.2, 13.8) and CHIKV-specific IgG titres (adjusted OR: 6.2, 95% CI: 2.8, 13.2, per one unit increase). CHIKV specific IgG titres were positively correlated with age, female gender and the severity of initial rheumatic symptoms. CONCLUSIONS: Our data support the roles of age, severity at presentation and CHIKV specific IgG titres for predicting CHIK-R. By identifying the prognostic value of the humoral immune response of the host, this work also suggest a significant contribution of the adaptive immune response to the physiopathology of CHIK-R and should help to reconsider the paradigm of this chronic infection primarily shifted towards the involvement of the innate immune response.

Structured self-management education maintained over two years in insufficiently controlled type 2 diabetes patients: the ERMIES randomised trial in Reunion Island.

BACKGROUND: Self-management education programs can reduce the complications and mortality in type 2 diabetes. The need to structure these programs for outpatient and community care with a vision for long-term maintenance has been recognised. In Reunion Island, an area affected by epidemiological and nutritional transition, diabetes affects 18% of the adult population over 30 years, with major social disparities, poor glycaemic control and frequent cardiovascular complications. METHODS/DESIGN: ERMIES is a randomised controlled trial designed to test the efficacy of a long-term (2 years) structured group self management educational intervention in improving blood glucose in non-recent, insufficiently controlled diabetes. After an initial structured educational cycle carried out blind for the intervention arm, patients will be randomised in two parallel group arms of 120 subjects: structured on-going group with educational intervention maintained over two years, versus only initial education. Education sessions are organised through a regional diabetes management network, and performed by trained registered nurses at close quarters. The educational approach is theoretically based (socio-constructivism, social contextualisation, empowerment, action planning) and reproducible, thanks to curricula and handouts for educators and learners. The subjects will be recruited from five hospital outpatient settings all over Reunion Island. The main eligibility criteria include: age ≥18 years, type 2 diabetes treated for more than one year, HbA1c ≥ 7.5% for ≥3 months, without any severe evolving complication (ischaemic or proliferative retinopathy, severe renal insufficiency, coronaropathy or evolving foot lesion), and absence of any major physical or cognitive handicap. The primary outcome measure is HbA1c evolution between inclusion and 2 years. The secondary outcome measures include anthropometric indicators, blood pressure, lipids, antidiabetic medications, level of physical activity, food ingestion, quality of life, social support, anxiety, depression levels and self-efficacy. An associated nested qualitative study will be conducted with 30 to 40 subjects in order to analyse the learning and adaptation processes during the education cycles, and throughout the study. CONCLUSIONS: This research will help to address the necessary but difficult issue of structuring therapeutic education in type 2 diabetes based on: efficacy and potential interest of organising on-going empowerment group-sessions, at close quarters, over the long term, in a heterogeneous socioeconomic environment. TRIAL REGISTRATION: ID_RCB number: 2011-A00046-35Clinicaltrials.gov number: NCT01425866.

Pandemic influenza due to pH1N1/2009 virus: estimation of infection burden in Reunion Island through a prospective serosurvey, austral winter 2009.

BACKGROUND: To date, there is little information that reflects the true extent of spread of the pH1N1/2009v influenza pandemic at the community level as infection often results in mild or no clinical symptoms. This study aimed at assessing through a prospective study, the attack rate of pH1N1/2009 virus in Reunion Island and risk factors of infection, during the 2009 season. METHODOLOGY/PRINCIPAL FINDINGS: A serosurvey was conducted during the 2009 austral winter, in the frame of a prospective population study. Pairs of sera were collected from 1687 individuals belonging to 772 households, during and after passage of the pandemic wave. Antibodies to pH1N1/2009v were titered using the hemagglutination inhibition assay (HIA) with titers ≥ 1/40 being considered positive. Seroprevalence during the first two weeks of detection of pH1N1/2009v in Reunion Island was 29.8% in people under 20 years of age, 35.6% in adults (20-59 years) and 73.3% in the elderly (≥ 60 years) (P<0.0001). Baseline corrected cumulative incidence rates, were 42.9%, 13.9% and 0% in these age groups respectively (P<0.0001). A significant decline in antibody titers occurred soon after the passage of the epidemic wave. Seroconversion rates to pH1N1/2009 correlated negatively with age: 63.2%, 39.4% and 16.7%, in each age group respectively (P<0.0001). Seroconversion occurred in 65.2% of individuals who were seronegative at inclusion compared to 6.8% in those who were initially seropositive. CONCLUSIONS: Seroincidence of pH1N1/2009v infection was three times that estimated from clinical surveillance, indicating that almost two thirds of infections occurring at the community level have escaped medical detection. People under 20 years of age were the most affected group. Pre-epidemic titers ≥ 1/40 prevented seroconversion and are likely protective against infection. A concern was raised about the long term stability of the antibody responses.

Perceived morbidity and community burden after a Chikungunya outbreak: the TELECHIK survey, a population-based cohort study.

BACKGROUND: Persistent disabilities are key manifestations of Chikungunya virus (CHIKV) infection, especially incapacitating polyarthralgia and fatigue. So far, little is known about their impact on health status. The present study aimed at describing the burden of CHIKV prolonged or late-onset symptoms on the self-perceived health of La Réunion islanders. METHODS: At 18 months after an outbreak of Chikungunya virus, we implemented the TELECHIK survey; a retrospective cohort study conducted on a random sample of the representative SEROCHIK population-based survey. A total of 1,094 subjects sampled for CHIKV-specific IgG antibodies in the setting of La Réunion island in the Indian Ocean, between August 2006 and October 2006, were interviewed about current symptoms divided into musculoskeletal/rheumatic, fatigue, cerebral, sensorineural, digestive and dermatological categories. RESULTS: At the time of interview, 43% of seropositive (CHIK+) subjects reported musculoskeletal pain (vs 17% of seronegative (CHIK-) subjects, P < 0.001), 54% fatigue (vs 46%, P = 0.04), 75% cerebral disorders (vs 57%, P < 0.001), 49% sensorineural impairments (vs 37%, P = 0.001), 18% digestive complaints (vs 15%, P = 0.21), and 36% skin involvement (vs 34%, P = 0.20) on average 2 years after infection (range: 15-34 months). After controlling for confounders such as age, gender, body mass index or major comorbidities in different Poisson regression models, 33% of joint pains were attributable to CHIKV, 10% of cerebral disorders and 7.5% of sensorineural impairments, while Chikungunya did not enhance fatigue states, digestive and skin disorders. CONCLUSIONS: On average, 2 years after infection 43% to 75% of infected people reported prolonged or late-onset symptoms highly attributable to CHIKV. These manifestations carry a significant burden in the community in the fields of rheumatology, neurology and sensorineural health.

Impact of Chikungunya virus infection on health status and quality of life: a retrospective cohort study.

BACKGROUND: Persistent symptoms, mainly joint and muscular pain and depression, have been reported several months after Chikungunya virus (CHIKV) infection. Their frequency and their impact on quality of life have not been compared with those of an unexposed population. In the present study, we aimed to describe the frequency of prolonged clinical manifestations of CHIKV infection and to measure the impact on quality of life and health care consumption in comparison with that of an unexposed population, more than one year after infection. METHODOLOGY/PRINCIPAL FINDINGS: In a retrospective cohort study, 199 subjects who had serologically confirmed CHIKV infection (CHIK+) were compared with 199 sero-negative subjects (CHIK-) matched for age, gender and area of residence in La Réunion Island. Following an average time of 17 months from the acute phase of infection, participants were interviewed by telephone about current symptoms, medical consumption during the last 12 months and quality of life assessed by the 12-items Short-Form Health Survey (SF-12) scale. At the time of study, 112 (56%) CHIK+ persons reported they were fully recovered. CHIK+ complained more frequently than CHIK- of arthralgia (relative risk = 1.9; 95% confidence interval: 1.6-2.2), myalgia (1.9; 1.5-2.3), fatigue (2.3; 1.8-3), depression (2.5; 1.5-4.1) and hair loss (3.8; 1.9-7.6). There was no significant difference between CHIK+ and CHIK- subjects regarding medical consumption in the past year. The mean (SD) score of the SF-12 Physical Component Summary was 46.4 (10.8) in CHIK+ versus 49.1 (9.3) in CHIK- (p = 0.04). There was no significant difference between the two groups for the Mental Component Summary. CONCLUSIONS/SIGNIFICANCE: More than one year following the acute phase of infection, CHIK+ subjects reported more disabilities than those who were CHIK-. These persistent disabilities, however, have no significant influence on medical consumption, and the impact on quality of life is moderate.

Estimating Chikungunya prevalence in La Réunion Island outbreak by serosurveys: two methods for two critical times of the epidemic.

BACKGROUND: Chikungunya virus (CHIKV) caused a major two-wave seventeen-month-long outbreak in La Réunion Island in 2005-2006. The aim of this study was to refine clinical estimates provided by a regional surveillance-system using a two-stage serological assessment as gold standard. METHODS: Two serosurveys were implemented: first, a rapid survey using stored sera of pregnant women, in order to assess the attack rate at the epidemic upsurge (s1, February 2006; n = 888); second, a population-based survey among a random sample of the community, to assess the herd immunity in the post-epidemic era (s2, October 2006; n = 2442). Sera were screened for anti-CHIKV specific antibodies (IgM and IgG in s1, IgG only in s2) using enzyme-linked immunosorbent assays. Seroprevalence rates were compared to clinical estimates of attack rates. RESULTS: In s1, 18.2% of the pregnant women were tested positive for CHIKV specific antibodies (13.8% for both IgM and IgG, 4.3% for IgM, 0.1% for IgG only) which provided a congruent estimate with the 16.5% attack rate calculated from the surveillance-system. In s2, the seroprevalence in community was estimated to 38.2% (95% CI, 35.9 to 40.6%). Extrapolations of seroprevalence rates led to estimate, at 143,000 and at 300,000 (95% CI, 283,000 to 320,000), the number of people infected in s1 and in s2, respectively. In comparison, the surveillance-system estimated at 130,000 and 266,000 the number of people infected for the same periods. CONCLUSION: A rapid serosurvey in pregnant women can be helpful to assess the attack rate when large seroprevalence studies cannot be done. On the other hand, a population-based serosurvey is useful to refine the estimate when clinical diagnosis underestimates it. Our findings give valuable insights to assess the herd immunity along the course of epidemics.