Sustainability of personal social networks of people with Down syndrome.

Research continues to demonstrate that the characteristics of one's social network could have an impact on the development of Alzheimer's disease. Given the predisposition of people with Down syndrome to develop Alzheimer's disease, analysis of their social networks has become an emerging focus. Previous pilot research demonstrated that the personal networks of people with DS could be quantitatively analyzed, with no difference between self-report and parent-proxy report. This manuscript focuses on a 12-month follow-up period with the same original participants (24 adults with Down syndrome). Their social networks demonstrated sustainability, but not improvement, as reported by people with DS (mean network size: 8.88; mean density: 0.73; mean constraint: 0.44; mean effective size: 3.58; mean max degree: 6.04; mean degree: 4.78) and their proxies (mean network size: 7.90; mean density: 0.82; mean constraint: 53.13; mean effective size: 2.87; mean max degree: 5.19; mean degree: 4.30). Intentional and continued efforts are likely needed in order to improve the social network measures of people with Down syndrome.

Occurrence of mosaic Down syndrome and prevalence of co-occurring conditions in Medicaid enrolled adults, 2016-2019.

BACKGROUND: Mosaic Down syndrome is a triplication of chromosome 21 in some but not all cells. Little is known about the epidemiology of mosaic Down syndrome. We described prevalence of mosaic Down syndrome and the co-occurrence of common chronic conditions in 94,533 Medicaid enrolled adults with any Down syndrome enrolled from 2016 to 2019. METHODS: We identified mosaic Down syndrome using the International Classification of Diseases and Related Health Problems, tenth edition code for mosaic Down syndrome and compared to those with nonmosaic Down syndrome codes. We identified chronic conditions using established algorithms and compared prevalence by mosaicism. RESULTS: In total, 1966 (2.08%) had claims for mosaic Down syndrome. Mosaicism did not differ by sex or race/ethnicity with similar age distributions. Individuals with mosaicism were more likely to present with autism (13.9% vs. 9.6%) and attention deficit hyperactivity disorder (17.7% vs. 14.0%) compared to individuals without mosaicism. In total, 22.3% of those with mosaic Down syndrome and 21.5% of those without mosaicism had claims for Alzheimer's dementia (Prevalence difference: 0.8; 95% Confidence interval: -1.0, 2.8). The mosaic group had 1.19 times the hazard of Alzheimer's dementia compared to the nonmosaic group (95% CI: 1.0, 1.3). DISCUSSION: Mosaicism may be associated with a higher susceptibility to certain neurodevelopmental and neurodegenerative conditions, including Alzheimer's dementia. Our findings challenge previous assumptions about its protective effects in Down syndrome. Further research is necessary to explore these associations in greater depth.

Health care satisfaction and medical literacy habits among caregivers of individuals with Down syndrome.

Patients with Down syndrome have significant specialized health care needs. Our objective was to understand the needs, satisfaction, and online habits of caregivers as they care for persons with Down syndrome. A mixed-method survey was distributed through REDCap from April 2022 to June 2022 in the United States; a Spanish-translated version was distributed through SurveyMonkey from August 2022 to March 2023 in Mexico. We received 290 completed responses from the United States and 58 from caregivers in Mexico. We found that current health care options are not meeting the needs of many individuals with DS in both the United States (39.7%) and Mexico (46.6%). Caregivers expressed frustrations with the inaccessibility and inapplicability of health care information. In particular, they often found the volume of information overwhelming, given their limited medical background. Additionally, health care recommendations were not customized and lacked practical recommendations. Most caregivers in both the United States (72.1%) and Mexico (82.8%) believe it is not easy to find answers to medical questions about their loved ones with DS. Online platforms with customized, specific health information related to DS could offer innovative solutions to these unmet needs for families and primary care providers.

Results of inaugural international Down Syndrome Societal Services and Supports survey.

PURPOSE: We previously designed the Down Syndrome Societal Services and Supports Survey (DS-4S) to measure country-specific supports for people with Down syndrome (DS) across multiple life domains (healthcare, education, policy, independence, and community inclusion). We now report and analyze the results. METHODS: We partnered with international DS consortia, who distributed the DS-4S to 154 cumulative members representing over 100 countries. Organizations were included if they had a holistic focus on the lives of people with DS and if at least 50% of their members either have DS or are family members of people with DS. Factor analysis was used to analyze the results. RESULTS: We received survey responses from 55 different organizations in 50 countries who met inclusion criteria. Each country had complete data for at least 4 of the 5 domains. The lowest 5 scores were from countries in Africa and Asia; the highest 5 scores were in Europe and North America. CONCLUSION: The responses to the DS-4S stratified countries within each surveyed domain. The DS-4S can now be used to track countries' progress over time and to determine which countries have best practices that might be replicated. We will publish the results and update them biennially at www.DownSyndromeQualityOfLife.com.

Parents of children with Down syndrome reflect on their postnatal diagnoses, 2003-2022.

A 2003 survey revealed the scope of mothers' dissatisfaction with their postnatal support following a diagnosis of Down syndrome (DS). Substantial proportions of mothers reported that providers conveyed diagnoses with pity, emphasized negative aspects of DS, and neglected to provide adequate materials explaining DS. This study follows up on the 2003 survey by assessing whether parents' experiences have improved. Four DS nonprofit organizations, which participated in the original study, distributed a mixed-methods survey to families who have had children with DS between 2003 and 2022. Quantitative analysis assessed correlations among responses and differences between the 2003 and 2022 survey groups. Open-ended responses were qualitatively analyzed. Compared to the 2003 findings, parents' perceptions of their postnatal care have not improved (N = 89). Parents are increasingly likely to report that their providers pitied them, omitted positive aspects of DS, and provided insufficient materials describing DS. Substantial proportions of parents reported fear (77%) and anxiety (79%), only 24% described receiving adequate explanatory materials, and parents were 45% likelier to report that physicians discussed negative aspects of DS than positive aspects. Qualitatively, substantial numbers of parents recounted insensitive conduct by providers. These results suggest that despite interventions, parents' experiences of postnatal diagnoses of DS have not improved over time. Certain provider behaviors-such as describing positive aspects of DS and providing comprehensive explanatory materials-can reduce fear and anxiety, pointing to directions for reform.

Tailored vs. General COVID-19 prevention for adults with mental disabilities residing in group homes: a randomized controlled effectiveness-implementation trial.

BACKGROUND: People with serious mental illness (SMI) and people with intellectual disabilities/developmental disabilities (ID/DD) are at higher risk for COVID-19 and more severe outcomes. We compare a tailored versus general best practice COVID-19 prevention program in group homes (GHs) for people with SMI or ID/DD in Massachusetts (MA). METHODS: A hybrid effectiveness-implementation cluster randomized control trial compared a four-component implementation strategy (Tailored Best Practices: TBP) to dissemination of standard prevention guidelines (General Best-Practices: GBP) in GHs across six MA behavioral health agencies. GBP consisted of standard best practices for preventing COVID-19. TBP included GBP plus four components including: (1) trusted-messenger peer testimonials on benefits of vaccination; (2) motivational interviewing; (3) interactive education on preventive practices; and (4) fidelity feedback dashboards for GHs. Primary implementation outcomes were full COVID-19 vaccination rates (baseline: 1/1/2021-3/31/2021) and fidelity scores (baseline: 5/1/21-7/30/21), at 3-month intervals to 15-month follow-up until October 2022. The primary effectiveness outcome was COVID-19 infection (baseline: 1/1/2021-3/31/2021), measured every 3 months to 15-month follow-up. Cumulative incidence of vaccinations were estimated using Kaplan-Meier curves. Cox frailty models evaluate differences in vaccination uptake and secondary outcomes. Linear mixed models (LMMs) and Poisson generalized linear mixed models (GLMMs) were used to evaluate differences in fidelity scores and incidence of COVID-19 infections. RESULTS: GHs (n=415) were randomized to TBP (n=208) and GBP (n=207) including 3,836 residents (1,041 ID/DD; 2,795 SMI) and 5,538 staff. No differences were found in fidelity scores or COVID-19 incidence rates between TBP and GBP, however TBP had greater acceptability, appropriateness, and feasibility. No overall differences in vaccination rates were found between TBP and GBP. However, among unvaccinated group home residents with mental disabilities, non-White residents achieved full vaccination status at double the rate for TBP (28.6%) compared to GBP (14.4%) at 15 months. Additionally, the impact of TBP on vaccine uptake was over two-times greater for non-White residents compared to non-Hispanic White residents (ratio of HR for TBP between non-White and non-Hispanic White: 2.28, p = 0.03). CONCLUSION: Tailored COVID-19 prevention strategies are beneficial as a feasible and acceptable implementation strategy with the potential to reduce disparities in vaccine acceptance among the subgroup of non-White individuals with mental disabilities. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04726371, 27/01/2021. https://clinicaltrials.gov/study/NCT04726371 .

COVID-19-Related Outcomes Among Group Home Residents with Serious Mental Illness in Massachusetts in the First Year of the Pandemic.

This study examined COVID-19 infection and hospitalizations among people with serious mental illness who resided in residential care group homes in Massachusetts during the first year of the COVID-19 pandemic. The authors analyzed data on 2261 group home residents and COVID-19 data from the Massachusetts Department of Public Health. Outcomes included positive COVID-19 tests and COVID-19 hospitalizations March 1, 2020-June 30, 2020 (wave 1) and July 1, 2020-March 31, 2021 (wave 2). Associations between hazard of outcomes and resident and group home characteristics were estimated using multi-level Cox frailty models including home- and city-level frailties. Between March 2020 and March 2021, 182 (8%) residents tested positive for COVID-19, and 51 (2%) had a COVID-19 hospitalization. Compared with the Massachusetts population, group home residents had age-adjusted rate ratios of 3.0 (4.86 vs. 1.60 per 100) for COVID infection and 13.5 (1.99 vs. 0.15 per 100) for COVID hospitalizations during wave 1; during wave 2, the rate ratios were 0.5 (4.55 vs. 8.48 per 100) and 1.7 (0.69 vs. 0.40 per 100). In Cox models, residents in homes with more beds, higher staff-to-resident ratios, recent infections among staff and other residents, and in cities with high community transmission risk had greater hazard of COVID-19 infection. Policies and interventions that target group home-specific risks are needed to mitigate adverse communicable disease outcomes in this population.Clinical Trial Registration Number This study provides baseline (i.e., pre-randomization) data from a clinical trial study NCT04726371.

Pneumonia vaccine response in individuals with Down syndrome at three specialty clinics.

Individuals with Down syndrome (DS) have been particularly impacted by respiratory conditions, such as pneumonia. However, the description of co-occurring recurrent infections, the response to pneumococcal immunization, and the association of these was previously unknown. We screened individuals with DS using an 11-item screener and prospectively collected pneumococcal titers and laboratory results. We found that the screener did not successfully predict which individuals with DS who would have inadequate pneumococcal titers. Thirty four of the 55 individuals with DS (62%) had abnormal pneumococcal titers demonstrating an inadequate response to routine immunization. In the absence of a valid screener, clinicians should consider screening all individuals with DS through the use of pneumococcal titers to 23 serotypes to assess vaccine response.

Health Surveillance in a Down Syndrome Specialty Clinic: Implementation of Electronic Health Record Integrations During the Coronavirus Disease 2019 Pandemic.

OBJECTIVE: To address gaps in routine recommended care for children with Down syndrome, through quality improvement during the coronavirus disease 2019 (COVID-19) pandemic. STUDY DESIGN: A retrospective chart review of patients with Down syndrome was conducted. Records of visits to the Massachusetts General Hospital Down Syndrome Program were assessed for adherence to 5 components of the 2011 American Academy of Pediatrics (AAP) Clinical Report, "Health Supervision for Children with Down Syndrome." The impact of 2 major changes was analyzed using statistical process control charts: a planned intervention of integrations to the electronic health record for routine health maintenance with age-based logic based on a diagnosis of Down syndrome, created and implemented in July 2020; and a natural disruption in care due to the COVID-19 pandemic, starting in March 2020. RESULTS: From December 2018 to March 2022, 433 patients with Down syndrome had 940 visits. During the COVID-19 pandemic, adherence to the audiology component decreased (from 58% to 45%, P < .001); composite adherence decreased but later improved. Ophthalmology evaluation remained stable. Improvement in adherence to 3 components (thyroid-stimulating hormone, hemoglobin, sleep study ever) in July 2020 coincided with electronic health record integrations. Total adherence to the 5 AAP guideline components was greater for follow-up visits compared with new patient visits (69% and 61%, respectively; P < .01). CONCLUSIONS: The COVID-19 pandemic influenced adherence to components of the AAP Health supervision for children with Down syndrome, but improvements in adherence coincided with implementation of our intervention and reopening after the COVID-19 pandemic.

Personal social networks of people with Down syndrome.

Studies in the neurotypical population have demonstrated that personal social networks can mitigate cognitive decline and the development of Alzheimer disease. To assess whether these benefits can also be extended to people with Down syndrome (DS), we studied whether and how personal networks can be measured in this population. We adapted a personal networks instrument previously created, validated, and implemented for the neurotypical population. We created two versions of the survey: one for participants with DS, ages 25 and older, and another for their study partners, who spent a minimum of 10 h/wk in a caregiver role. Participants with DS gave concordant data to those of study partners. Their personal networks included a median network size of 7.50, density 0.80, constraint 46.00, and effective size 3.07. Personal networks were composed of 50% kin, 80% who live within 15 miles, and 80% who eat a healthy diet. In this proof-of-principle study, we demonstrated that the personal networks of people with DS can be quantitatively analyzed, with no statistical difference between self-report and parent-proxy report. Future research efforts can now evaluate interventions to enhance personal networks for preventing Alzheimer disease in this population.

Global health measures from a National Down Syndrome Registry.

People with Down syndrome (DS) have a unique medical profile which may impact views of health. We aimed to study the use of global health measures for DS in a national cohort. We prospectively surveyed parents of individuals with DS from the DS-Connect® registry with validated Patient Reported Outcomes Measurement Information System (PROMIS)® instruments of global health. Analyses included use of scoring manuals and the PROMIS® scoring service, descriptive statistics, and t-tests. We received completed surveys from 223 parents of individuals with DS; previously published limitations of the instrument in this population were shown again. T-scores differed from the available comparative standardized scores to these measures from PROMIS® reference population on Fatigue (p < 0.001) and Global Health (p < 0.001), but not on Pain Interference (p = 0.41).

Validation of a predictive model for obstructive sleep apnea in people with Down syndrome.

Detecting obstructive sleep apnea (OSA) is important to both prevent significant comorbidities in people with Down syndrome (DS) and untangle contributions to other behavioral and mental health diagnoses. However, laboratory-based polysomnograms are often poorly tolerated, unavailable, or not covered by health insurance for this population. In previous work, our team developed a prediction model that seemed to hold promise in identifying which people with DS might not have significant apnea and, consequently, might be able to forgo a diagnostic polysomnogram. In this study, we sought to validate these findings in a novel set of participants with DS. We recruited an additional 64 participants with DS, ages 3-35 years. Caregivers completed the same validated questionnaires, and our study team collected vital signs, physical exam findings, and medical histories that were previously shown to be predictive. Patients then had a laboratory-based polysomnogram. The best modeling had a validated negative predictive value of 50% for an apnea-hypopnea index (AHI) > 1/hTST and 73.7% for AHI >5/hTST. The positive predictive values were 60% and 39.1%, respectively. As such, a clinically reliable screening tool for OSA in people with DS was not achieved. Patients with DS should continue to be monitored for OSA according to current healthcare guidelines.

Cardiometabolic profiles in children and adults with overweight and obesity and down syndrome.

Individuals with Down syndrome (DS) are at increased risk for being overweight/obese, but the associated cardiometabolic risk (CR) is not clear. Cross-sectional anthropometric and clinical laboratory data from a multi-site, international cohort of individuals with DS were analyzed to determine cardiometabolic risk by reporting observed distributions of cardiometabolic biomarkers in overweight/obese individuals with DS throughout the lifespan. Descriptive statistics and regression analyses by age categories determined the distributive percentiles for cardiometabolic biomarkers and tested for adiposity as a predictor of CR. Across seven DS clinics, data were collected on 240 patients between the ages of 3 and 63 years, with one quarter overweight and three quarters obese among children and nearly all adults being obese. In children and adults, most cardiometabolic biomarker profiles showed distributive values within normal ranges. Blood lipids were positively associated with body mass index (BMI) in children (high density lipid-cholesterol, p = 0.01; low density lipid-cholesterol, p = 0.02). Levels of hs-CRP were elevated in both children and adults, with BMI positively associated with hs-CRP in adults with DS (p = 0.04). Liver enzyme values were positively associated with BMI in children and adults. The data suggest that in contrast to the general population, in individuals with Down syndrome, being overweight and obese does not appear to confer a significantly increased risk for cardiometabolic disease by biomarker profile. Individuals with DS who are overweight/obese appear to have unique cardiometabolic profiles unrelated to adiposity, notable for increased hs-CRP and normal HA1c levels.

Healthcare experiences of patients with Down syndrome who are Black, African American, of African descent, or of mixed race.

Scant research has explored the healthcare experiences of people with Down syndrome (DS) in the United States who are Black, African American, of African descent, or of mixed race. The purpose of this study was to identify and describe the barriers and facilitators that such patients and their caregivers face when accessing healthcare. We gathered data in three ways: focus groups with caregivers, a national survey completed by caregivers, and in-depth interviews with primary care providers. Many caregivers and primary care physicians felt that patients with DS who are Black, African American, of African descent, or of mixed race receive a lower quality of medical care than their white counterparts with DS. Caregivers mentioned feeling tired of being reminded by the medical community about their race and wanting acknowledgment that raising a child with DS can be hard at times. Many felt that the medical community's conscious and unconscious racial biases do negatively impact the care of their loved ones with DS. Caregivers desired more race concordant medical providers or, when not possible, medical providers who are willing to learn more about DS and build trusted, longitudinal relationships. Primary care providers discussed the need for funded resources and support services to effectively care for their patients with DS.

Healthcare experiences of patients with Down syndrome from primarily Spanish-speaking households.

We report on the health care experiences of individuals with Down syndrome (DS) from families who are primarily Spanish-speaking. Data were collected through three methods: (1) a nationally distributed, 20-item survey, (2) two focus groups with seven family caregivers of individuals with DS who self-identified as living in primarily Spanish speaking households, and (3) 20 interviews with primary care providers (PCPs) who care for patients who are underrepresented minorities. Standard summary statistics were used to analyze the quantitative survey results. Focus group and interview transcripts, as well as an open-ended response question in the survey, were analyzed using qualitative coding methods to identify key themes. Both caregivers and PCPs described how language barriers make giving and receiving quality care difficult. Caregivers additionally described condescending, discriminatory treatment within the medical system and shared feelings of caregiver stress and social isolation. Challenges to care experienced by families of individuals with DS are compounded for Spanish-speaking families, where the ability to build trust with providers and in the health care system may be compromised by cultural and language differences, systemic issues (lack of time or inability to craft more nuanced schedules so that patients with higher needs are offered more time), mistrust, and sometimes, overt racism. Building this trust is critical to improve access to information, care options, and research opportunities, especially for this community that depends on their clinicians and nonprofit groups as trusted messengers. More study is needed to understand how to better reach out to these communities through primary care clinician networks and nonprofit organizations.

Views on the impact of the COVID-19 pandemic on health in people with Down syndrome from diverse backgrounds.

Down syndrome (DS) has a unique medical and psychological profile. To date, few studies have asked individuals with DS about their views of health, and fewer have explored the impact of COVID-19 on the health of individuals with DS and their families. We used a mixed methods approach including two studies on the health of individuals with DS and their parents conducted during the COVID-19 pandemic: (1) eight virtual focus groups, comprised of 20 parents and 8 individuals with DS to obtain participants' views of health, and (2) a 20-item questionnaire on health care experience of patients with DS who are African American or come from primarily Spanish-speaking homes. Focus group transcripts were coded using a hybrid inductive/deductive framework and thematically analyzed using the Framework Method. This questionnaire included questions regarding the impact of COVID-19 on caregivers and their loved ones with DS; responses to these questions were summarized using descriptive statistics. Individuals with DS discussed the impact of the COVID-19 pandemic on their physical and social health including masking, online learning, and online communication with friends and family. Parents of individuals with DS discussed how the COVID-19 pandemic negatively impacted their child's physical, social, and mental health, as a result of virtual schooling and decreased socialization. There were unexpected positives of the pandemic such as improved hygiene and eased scheduling with telehealth visits. Caregivers noted COVID-19 impacted their own anxiety, employment, and other domains that have potential ripple effects on the health of their children. The COVID-19 pandemic had a pervasive impact on the mental health and wellness of caregivers as well as the physical, social, and mental health of individuals with DS.

Biometric magnetic resonance imaging analysis of fetal brain development in Down syndrome.

OBJECTIVES: To assess brain development in living fetuses with Down syndrome (DS) by biometric measurements on fetal brain magnetic resonance images (MRI). METHODS: We scanned 10 MRIs of fetuses with confirmed trisomy 21 at birth and 12 control fetal MRIs without any detected anomalies. Fetal brain MRIs were analyzed using 14 fetal brain and skull biometric parameters. We compared measures between DS and controls in both raw MRIs and motion-corrected and anterior-posterior commissure-aligned images. RESULTS: In the reconstructed images, the measured values of the height of the cerebellar vermis (HV) and anteroposterior diameter of the cerebellar vermis (APDV) were significantly smaller, and the anteroposterior diameter of the fourth ventricle (APDF) was significantly larger in fetuses with DS than controls. In the raw MRIs, the measured values of the right lateral ventricle were significantly larger in fetuses with DS than in controls. Logistic regression analyses revealed that a new parameter, the cerebellar-to-fourth-ventricle ratio (i.e., (APDV * Height of the vermis)/APDF), was significantly smaller in fetuses with DS than controls and was the most predictive to distinguish between fetuses with DS and controls. CONCLUSIONS: The study revealed that fetuses with DS have smaller cerebellums and larger fourth ventricles compared to the controls.

Designing an international survey for organisations serving people with Down syndrome.

BACKGROUND: Down syndrome is the most common liveborn genetic condition. However, there are no surveys measuring societal services and supports for people with Down syndrome. We developed a questionnaire so that initiatives could be targeted towards countries most in need of assistance. METHOD: We formed a geographically diverse group of physicians, family members of people with Down syndrome, and members of Down syndrome not-for-profit organisations to create a survey of societal services and supports. We used a modified Delphi method and disseminated the survey to Down syndrome non-profit organisations worldwide. RESULTS: Our survey consists of 61 items categorised within five domains: Education, Community Inclusion, Independence, Healthcare, and Social and Policy Issues. CONCLUSIONS: We developed a survey to measure societal services and supports available to people with Down syndrome as perceived by organisational leaders. Our methods might serve as a blueprint for other populations of people with intellectual and developmental disabilities.

Aberrant Function of the C-Terminal Tail of HIST1H1E Accelerates Cellular Senescence and Causes Premature Aging.

Histones mediate dynamic packaging of nuclear DNA in chromatin, a process that is precisely controlled to guarantee efficient compaction of the genome and proper chromosomal segregation during cell division and to accomplish DNA replication, transcription, and repair. Due to the important structural and regulatory roles played by histones, it is not surprising that histone functional dysregulation or aberrant levels of histones can have severe consequences for multiple cellular processes and ultimately might affect development or contribute to cell transformation. Recently, germline frameshift mutations involving the C-terminal tail of HIST1H1E, which is a widely expressed member of the linker histone family and facilitates higher-order chromatin folding, have been causally linked to an as-yet poorly defined syndrome that includes intellectual disability. We report that these mutations result in stable proteins that reside in the nucleus, bind to chromatin, disrupt proper compaction of DNA, and are associated with a specific methylation pattern. Cells expressing these mutant proteins have a dramatically reduced proliferation rate and competence, hardly enter into the S phase, and undergo accelerated senescence. Remarkably, clinical assessment of a relatively large cohort of subjects sharing these mutations revealed a premature aging phenotype as a previously unrecognized feature of the disorder. Our findings identify a direct link between aberrant chromatin remodeling, cellular senescence, and accelerated aging.

Estimation of the number of people with Down syndrome in Australia and New Zealand.

PURPOSE: Previous research estimated the effect of selective terminations on birth prevalence and population prevalence of people with Down syndrome (DS) in the United States and Europe. This study provides comparative data from Australia and New Zealand. METHOD: The number of live births (LBs) with DS-in the absence of DS-related terminations of pregnancy-was estimated on the maternal age distribution in the general population. Actual LBs were modeled on registry data. We applied constructed survival curves to annual LBs to predict population numbers. RESULTS: For 2016-2020, we estimated 265 annual LBs with DS (1 in 1158) in Australia and 41 annual LBs (1 in 1450) in New Zealand. For this period, the reduction percentage-the net result of DS-related terminations on LB prevalence-was estimated at 66% for Australia, 71% for New Zealand, 62% for Europe (excluding the former East Bloc), and only 32% for the United States. CONCLUSION: The total population of people with DS has been decreasing since 2000 in Europe (West Bloc) and 2011 in New Zealand owing, in large part, to increased selective terminations. By contrast, the population continues to increase, as of 2020, in Australia and the United States.