Postnatal methylmercury exposure and neurodevelopmental outcomes at 7 years of age in the Seychelles Child Development Study Nutrition Cohort 2.

BACKGROUND: Consumption of fish yields many nutritional benefits, but also results in exposure to methylmercury (MeHg). The developing brain is known to be particularly susceptible to MeHg toxicity in high doses. However, the potential impact of low-level environmental exposure from fish consumption on children's neurodevelopment remains unclear. METHODS: We investigated postnatal MeHg exposure at 7 years and its association with a battery of 17 neurodevelopmental outcomes in a subset of children (n = 376) from 1535 enrolled mother-child pairs in Nutrition Cohort 2 of the Seychelles Child Development Study (SCDS NC2). Each outcome was modeled in relation to postnatal MeHg exposure using linear regression, adjusting for prenatal MeHg exposure, levels of maternal polyunsaturated fatty acids (PUFA), and several other covariates known to be associated with neurodevelopmental outcomes. RESULTS: Median postnatal MeHg exposure at 7 years was 2.5 ppm, while the median prenatal MeHg exposure was 3.5 ppm. We found no statistically significant associations between postnatal MeHg exposure and any of the 17 neurodevelopmental outcomes after adjusting for prenatal MeHg exposure and other covariates. CONCLUSIONS: These findings are consistent with previous cross-sectional analyses of the SCDS Main Cohort. Continued follow-up of the entire NC2 cohort at later ages with repeated exposure measures is needed to further confirm these findings.

Associations between time-weighted postnatal methylmercury exposure from fish consumption and neurodevelopmental outcomes through 24 years of age in the Seychelles Child Development Study Main Cohort.

PURPOSE: Methylmercury (MeHg) is a known neurodevelopmental toxicant in sufficient dosage and is universally found in fish. Current fish advisories for children are based on epidemiology studies examining prenatal exposure with a premise that MeHg exposure resulting from children eating fish could also be neurotoxic and have long-term consequences. However, the evidence that this assumption is true is limited. We investigated postnatal MeHg exposure from regular fish consumption using time weighted Hg measurements to determine if there are neurotoxic consequences. METHODS: We examined 85 neurodevelopmental outcomes measured from ages 9-24 years in the Seychelles Child Development Study Main Cohort (n = 312-550) and examined their association with time-weighted measures of postnatal MeHg exposure in childhood and early adulthood. Postnatal MeHg exposure measured in the first cm of participants' hair samples collected at seven evaluations were used to create two time-weighted (TW) average MeHg exposure metrics, one for childhood (TW-C) and the other for early adulthood (TW-A). TW-C was based on Hg measures at three ages between 6 months and 5.5 years, and TW-A was based on Hg measured at up to four ages between 17 and 24 years. We examined the association between each of these exposure metrics and the neurodevelopmental outcomes using linear regression with adjustment for covariates known to influence neurodevelopmental outcomes. RESULTS: There were 14 statistically significant associations between a postnatal metric and an endpoint. Six were associated with the TW-C and eight with the TW-A. Thirteen were adverse. Only the TW-C association at 9 years with the Bender Gestalt error score showed improvement. TW-C was adversely associated at 9 years with the Continuous Performance Task risk score, at 22 years with the Boston Naming Test (BNT) total and no cues scores, and at 24 years with the Test of Variables of Attention (TOVA) auditory response time variability and visual response time mean on the logarithmic scale. TW-A was adversely associated at 17 years with the Wisconsin Card Sorting Test % total errors, the Woodcock-Johnson passage comprehension, and the CANTAB rapid visual information processing false alarms, and at 22 years with the BNT total and no cue scores, the CANTAB rapid visual information processing false alarms and the intra-extra dimensional shift total errors and trials. CONCLUSION: These findings suggest that postnatal MeHg exposure may be adversely associated with neurodevelopmental outcomes in early adulthood. However, the associations are statistical and of unknown, if any, clinical significance. The results need confirmation in other cohorts.

Genomic Epidemiology of SARS-CoV-2 in Seychelles, 2020-2021.

Seychelles, an archipelago of 155 islands in the Indian Ocean, had confirmed 24,788 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the 31st of December 2021. The first SARS-CoV-2 cases in Seychelles were reported on the 14th of March 2020, but cases remained low until January 2021, when a surge was observed. Here, we investigated the potential drivers of the surge by genomic analysis of 1056 SARS-CoV-2 positive samples collected in Seychelles between 14 March 2020 and 31 December 2021. The Seychelles genomes were classified into 32 Pango lineages, 1042 of which fell within four variants of concern, i.e., Alpha, Beta, Delta and Omicron. Sporadic cases of SARS-CoV-2 detected in Seychelles in 2020 were mainly of lineage B.1 (lineage predominantly observed in Europe) but this lineage was rapidly replaced by Beta variant starting January 2021, and which was also subsequently replaced by the Delta variant in May 2021 that dominated till November 2021 when Omicron cases were identified. Using the ancestral state reconstruction approach, we estimated that at least 78 independent SARS-CoV-2 introduction events occurred in Seychelles during the study period. The majority of viral introductions into Seychelles occurred in 2021, despite substantial COVID-19 restrictions in place during this period. We conclude that the surge of SARS-CoV-2 cases in Seychelles in January 2021 was primarily due to the introduction of more transmissible SARS-CoV-2 variants into the islands.

Delivery Mode and Child Development at 20 Months of Age and 7 Years of Age in the Republic of Seychelles.

OBJECTIVE: To determine if cesarean delivery is adversely associated with child neurodevelopment as measured at 20 months and 7 years. METHODS: In a prospective cohort study (n = 1328) in the Republic of Seychelles, we examined the association between mode of delivery and 22 measures of child neurodevelopment spanning multiple domains: cognition, executive and psychomotor function, language development, behavior, scholastic achievement, and social communication. Using multivariable linear regression, we evaluated the relationship between delivery mode (Cesarean/vaginal delivery) and each developmental outcome, while controlling for relevant covariates including child sex and age, maternal age, maternal IQ, whether both parents lived with the child, and Hollingshead socioeconomic status. RESULTS: At 20 months, children born via cesarean delivery had slightly higher scores (ß = 0.11, 95% confidence interval: 0.00, 0.21) on the Infant Behavior Questionnaire-Revised Positive Affectivity/Surgency subtest, a measure of infant temperament, as compared to vaginal delivery. Delivery mode was not associated with any of the 7-year developmental outcomes. CONCLUSIONS FOR PRACTICE: Our study does not support the notion that cesarean delivery is associated with child neurodevelopmental outcomes.

Consumption of Monounsaturated Fatty Acids Is Associated with Improved Cardiometabolic Outcomes in Four African-Origin Populations Spanning the Epidemiologic Transition.

Long-chain omega-3 PUFAs, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are of increasing interest because of their favorable effect on cardiometabolic risk. This study explores the association between omega 6 and 3 fatty acids intake and cardiometabolic risk in four African-origin populations spanning the epidemiological transition. Data are obtained from a cohort of 2500 adults aged 25-45 enrolled in the Modeling the Epidemiologic Transition Study (METS), from the US, Ghana, Jamaica, and the Seychelles. Dietary intake was measured using two 24 h recalls from the Nutrient Data System for Research (NDSR). The prevalence of cardiometabolic risk was analyzed by comparing the lowest and highest quartile of omega-3 (EPA+ DHA) consumption and by comparing participants who consumed a ratio of arachidonic acid (AA)/EPA + DHA ≤4:1 and >4:1. Data were analyzed using multiple variable logistic regression adjusted for age, gender, activity, calorie intake, alcohol intake, and smoking status. The lowest quartile of EPA + DHA intake is associated with cardiometabolic risk 2.16 (1.45, 3.2), inflammation 1.59 (1.17, 2.16), and obesity 2.06 (1.50, 2.82). Additionally, consuming an AA/EPA + DHA ratio of >4:1 is also associated with cardiometabolic risk 1.80 (1.24, 2.60), inflammation 1.47 (1.06, 2.03), and obesity 1.72 (1.25, 2.39). Our findings corroborate previous research supporting a beneficial role for monounsaturated fatty acids in reducing cardiometabolic risk.

A Comparative Study of the Health Care Delivery Systems in the Indian Ocean: What can Comoros Islands Learn from Mauritius and Seychelles?

In recent years, there have been significant efforts to examine the organization and performance of health systems. This study's main purpose is to compare health systems and analyze the health status of the citizens of Comoros, Mauritius, and Seychelles, with the intention of providing policy recommendations for Comoros. Peer-reviewed studies and reports published by non-governmental organizations and international agencies were systematically collected through large database searches, filtered through methodological inclusion criteria, and organized into the World Health Organization (WHO) building blocks framework. The literature review demonstrates that health outcomes have dramatically improved over the past decades in Mauritius and Seychelles but not in Comoros. As of 2015, Mauritius and Seychelles were among the few African countries to have achieved almost all the Millennium Development Goals, whereas Comoros still struggles to reduce child mortality and improve maternal health. In contrast, the total health expenditure of the three island states, as a percentage of gross domestic product (GDP), seemed similar over the studied time period.

Trends in mortality from external causes in the Republic of Seychelles between 1989 and 2018.

Data on injury-related mortality are scarce in the African region. Mortality from external causes in the Seychelles was assessed, where all deaths are medically certified and the population is regularly enumerated. The four fields for underlying causes of death recorded were reviewed in the national vital statistics register. The age-standardised mortality rates were estimated (per 100,000 person-years) from external causes in 1989-1998, 1999-2008, and 2009-2018. Mortality rates per 100,000 person-years from external causes were 4-5 times higher among males than females, and decreased among males over the three 10-year periods (127.5, 101.4, 97.1) but not among females (26.9, 23.1, 26.9). The contribution of external causes to total mortality did not change markedly over time (males 11.6%, females 4.3% in 1989-2018). Apart from external deaths from undetermined causes (males 14.6, females 2.4) and "other unintentional injuries" (males 14.1, females 8.0), the leading external causes of death in 2009-2018 were drowning (25.9), road traffic injuries (18.0) and suicide (10.4) among males; and road traffic injuries (4.6), drowning (3.4) and poisoning (2.6) among females. Mortality from broad categories of external causes did not change consistently over time but rates of road traffic injuries increased among males. External causes contributed approximately 1 in 10 deaths among males and 1 in 20 among females, with no marked change in cause-specific rates over time, except for road traffic injuries. These findings emphasise the need for programs and policies in various sectors to address this large, but mostly avoidable health burden.

Association between the spread of COVID-19 and weather-climatic parameters.

OBJECTIVE: To explore whether the climate has played a role in the COVID-19 outbreak, we compared virus lethality in countries closer to the Equator with others. Lethality in European territories and in territories of some nations with a non-temperate climate was also compared. MATERIALS AND METHODS: Lethality was calculated as the rate of deaths in a determinate moment from the outbreak of the pandemic out of the total of identified positives for COVID-19 in a given area/nation, based on the COVID-John Hopkins University website. Lethality of countries located within the 5th parallels North/South on 6 April and 6 May 2020, was compared with that of all the other countries. Lethality in the European areas of The Netherlands, France and the United Kingdom was also compared to the territories of the same nations in areas with a non-temperate climate. RESULTS: A lower lethality rate of COVID-19 was found in Equatorial countries both on April 6 (OR=0.72 CI 95% 0.66-0.80) and on May 6 (OR=0.48, CI 95% 0.47-0.51), with a strengthening over time of the protective effect. A trend of higher risk in European vs. non-temperate areas was found on April 6, but a clear difference was evident one month later: France (OR=0.13, CI 95% 0.10-0.18), The Netherlands (OR=0.5, CI 95% 0.3-0.9) and the UK (OR=0.2, CI 95% 0.01-0.51). This result does not seem to be totally related to the differences in age distribution of different sites. CONCLUSIONS: The study does not seem to exclude that the lethality of COVID-19 may be climate sensitive. Future studies will have to confirm these clues, due to potential confounding factors, such as pollution, population age, and exposure to malaria.

An Observational Study of Human Leptospirosis in Seychelles.

A 1-year population-based prospective study was launched in Seychelles, a country with one of the highest human incidence of leptospirosis worldwide, to describe the characteristic features of the epidemiology of the disease and highlight the most prominent risk factors. Diagnosis was based on the IgM enzyme-linked immunosorbent assay, microscopic agglutination test, and real-time PCR. A standardized questionnaire was administered to 219 patients aged ≥ 13 years consulting for acute febrile illness. The high incidence of leptospirosis in Seychelles was confirmed. The disease was particularly severe, as the case fatality rate was 11.8%. Leptospirosis was positively associated in univariate analysis with socio-professional and clinical variables including gardening/farming, oliguria, jaundice, conjunctivitis, history of hepatitis C virus infection, anemia, thrombocytopenia, and/or biological renal failure. Epidemiological analyses of the questionnaires highlighted a link of the disease with living in houses (versus apartment), the presence of animals around and in houses, gardening, and misuse of personal protective equipment. Multivariate analyses indicated that being a farmer/landscaper and having cattle and cats around the home are the most significant drivers of leptospirosis. Biological features most associated with leptospirosis were thrombocytopenia, leukocytosis, high values for renal function tests, and elevated total bilirubin. We report changes in behavior and exposure compared with data collected on leptospirosis 25 years ago, with indication that healthcare development has lowered case fatality. Continuous health education campaigns are recommended as well as further studies to clarify the epidemiology of human leptospirosis, especially the role of domestic animals.

Associations between self-reported sleep duration and cardiometabolic risk factors in young African-origin adults from the five-country modeling the epidemiologic transition study (METS).

OBJECTIVES: To investigate associations between self-reported sleep duration and cardiometabolic (CM) risk factors in African-origin adults residing in five countries spanning the epidemiologic transition. DESIGN: Cross-sectional. SETTING AND PARTICIPANTS: Ghanaian (n = 491), South African (n = 503), Jamaican (n = 508), Seychellois (n = 501) and American (n = 480) men and women. MEASUREMENTS: Self-reported sleep duration was obtained using questionnaires. Sex- and site-stratified logistic regression analyses investigated relationships between sleep duration, individual CM risk factors and a binary CM risk variable (presence of ≥3 CM risk factors), adjusting for age, physical activity and education. RESULTS: Sleep duration distributions varied by cohort: 44.5%, 41.4%, 35.9%, 16.8% and 2.5% of American, Jamaican, Seychellois, Ghanaian and South African men reported <7 h sleep per night respectively (p < 0.001). Similarly, 42.6%, 28.6%, 25.2%, 12.8% and 1.5% of American, Jamaican, Seychellois, Ghanaian and South African women reported <7 h sleep respectively (p < 0.001). American men reporting ≤6 h sleep were more likely to be in the elevated CM risk group (OR: 2.52, 95%CI: 1.02, 6.22, p = 0.045) and to have a high waist circumference (OR: 2.44, 95%CI: 1.07, 5.57, p = 0.034) compared to those reporting 8 h sleep. Jamaican women reporting ≤6 h sleep (OR: 2.53, 95%CI: 1.19, 5.36, p = 0.016) and American women reporting 7 h sleep (OR: 2.71, 95%CI: 1.17, 6.26, p = 0.002) were more likely to be obese than those reporting 8 h sleep. CONCLUSIONS: Associations between short sleep and CM risk factors were only evident in the American men and women and Jamaican women. Future interventions to address CM risk and sleep health may need to be country-specific when targeting high-risk populations.

Socioeconomic development in Seychelles: an overview.

Although Seychelles is a very small country with a population of 79 879 in 2003, it has a complex and under-studied society and economy. In order to provide broad context, this article provides an overview of the national population trends before framing Seychelles in the concept of a small island developing state (SIDS). This serves to highlight macroeconomic and geographical realities. The article then gives a short sketch of the transition of the economy from the colonial period to the present. These two sections provide understanding of the country's vulnerabilities and export- orientated productive base, thereby explicating the economic input to social development. The next section provides analysis of a cross- section of key indicators of social development. This demonstrates the comparatively high levels of human development in Seychelles. Finally, the article briefly examines how social development has been sustained since independence and outlines challenges to maintaining socio-economic gains in the medium-term future.

Health in Seychelles - an overview.

Health in Seychelles has improved significantly over the past three decades, largely as a result of investment not only in the health services, but also in other social sectors that have direct impact on child survival and the health of individuals. Through different stages of the evolution of the health care system there have been close links between health policy and strategy, the overall national development efforts and the wider social and economic environment. Awareness of these links are useful in the understanding of current health issues such as the lifestyle related patterns of morbidity and mortality, characterised by non-communicable diseases and HIV/AIDS, the high demands for health care services, and evolving relationships between the public and private sectors.

The Seychelles Dental Service.

The Seychelles Dental Service dates back to the 1920s, growing from rudimentary dentistry to the evidence-based dentistry of today. Until the 1970s, dental care was provided by a small number of dentists. However, since the establishment of the School Dental Service (SDS) in the 1980s, child oral health has been the responsibility of Dental Therapists (DTs). Today Seychelles has a well organised oral health care system in place with modern infrastructure and equipment and trained personnel. Locally trained DTs constitute 85% of the SDS workforce. A national oral health plan serves as a guide to ensure that programmes are developed in accordance with WHO global oral health goals, guided by periodic reviews. We present a resume of the major strengths and challenges of the Seychelles Dental Service, concluding with recommendations for staff development. Findings and recommendations of reviews and assessments of various dental health issues conducted in the country between 1977 and 1999 are summarised in the appendix.

Increasing prevalence of overweight among Seychelles children, 1998-2002.

To examine the prevalence and trends in excess weight among children in the Seychelles. Serial surveys of weight and height were conducted each year between 1998-2002 in all students attending four school grades (crèche, 4th, 7th and 10th years of compulsory school). Overweight and obesity were defined using age-specific body mass index (BMI) criteria of the International Obesity Task Force. Two questions explored physical activity at leisure time and daily walking time. From an eligible total of 32 077 observations between 1998-2002, data were available in 22 694 (71%), which corresponded to 17 627 separate children. Median age in the four grades was respectively 5.5, 9.2, 12.6, and 15.8 years. The overall prevalence of excess weight ('overweight' and 'obese' categories combined) was 10.5% in boys and 16.4% in girls. From 1998 to 2002, the prevalence of excess weight increased from 8.4% to 11.8% in boys and from 11.9% to 18.4% in girls. The increase of excess weight over calendar years was particularly marked among the younger children. Only a quarter of children reported walking at least 30minutes per day. Leisure physical activity was inversely associated with excess body weight. The prevalence of excess body weight was high among school children of Seychelles and increased substantially over a five-year period. This calls for prompt and energetic policies and programs to promote physical activity and healthy nutrition among children.

Principles of studying low-level neurotoxic exposures in children: using the Seychelles Child Development Study of methyl mercury as a prototype.

Epidemiological studies to determine the impact of low level toxic exposure on child development are important in guiding clinical and public health action. However, carrying out such studies and interpreting their findings presents a number of significant challenges to the investigators. First, they must find a cohort with suitable exposure, select a biomarker that will accurately determine the level of exposure and determine the endpoints that are most likely to detect subtle differences in neurodevelopment. Following that, the logistics of the study must be organised and collaboration established with the local population and health authorities. To accurately interpret the data, they must also accurately determine covariates that impact child development. After the data are collected, interpreting the findings presents a further challenge. Throughout this process, the study must adhere to fundamental epidemiological principles and clearly defined statistical approaches. This paper discusses those principles and uses the Seychelles Child Development Study to show how one epidemiological study addressed them.

The oral health status of children aged 12 years in Seychelles in the years 1994 and 2000.

The results of two national oral health surveys in 1993/4 led the Seychelles School Dental Service (SDS) to implement an oral health improvement strategy through the adoption of a targeted population approach. The aim was to attain the World Health Organization's (WHO) goal for 12-year-olds, of a DMFT (decayed, missing, filled permanent teeth) of less than 3.0, by the year 2000. Primary 5 (P5) children from all state schools were selected as the target population. Although all the children (1538) were exposed to the targeted service interventions, 500 were sampled out for study, through random sampling of school class lists. Data was collected at the beginning of 1998 and end of 2000, through clinical examination and self-administered questionnaires. All examinations and interventions were carried out by dental therapists (DTs), in their respective clinics. For the purpose of this paper comparisons made between 12-year-olds of 1994 and those of 2000 are based only on the dental examination data. Interventions were spread over three years from 1998 to 2000. These included an initial dental examination followed by any dental treatment required, an annual recall visit, dental health education at class and individual level, and weekly school-based fluoride mouth rinses. Parameters investigated were 1) community periodontal index of treatment needs (CPITN), 2) dental health status (DMFT), 3) enamel defect, and 4) clinic attendance. All parameters improved significantly between the cohort of 1994 and that of 2000. The proportion of children and of sextants with healthy gingivae increased from 3.4% to 51.8% and from 25.9% to 70.9% respectively. Children with no enamel defects increased from 51.1% to. 92.6%, while children with newly decayed teeth decreased from 61% to 33%. The mean number of newly decayed teeth fell from 2.0 to 0.8. The proportion of children attending their clinic at least once a year for check up increased from 51% in 1994 through 73% in 1998 to almost 100% in 2000. The WHO goal for children aged 12 years to have a DMFT of less than 3 was met, with a change from 3.2 in 1994 to 1.9 in 2000.

Education in Seychelles: an overview.

The paper gives a brief description of the Seychelles education system, its main characteristics and its major achievements. It outlines the various reforms that have been instituted since independence from the British in 1976. It reviews the objectives of the reforms, which were to ensure ten years of universal education and to bring about significant improvements in the quality of education throughout the system. The second part of the paper examines the extent to which the main issues targeted by the reforms have been resolved and the related aspects of quality enhancement. Finally, future directions as outlined in the Ministry of Education's Strategic Plan are considered.