Objective To calculate a reliable estimate of the population prevalence of Down syndrome in the US. Study design The annual number of births of infants with Down syndrome were estimated by applying published birth prevalence rates of Down syndrome by maternal age to US data from the Centers for Disease Control and Prevention for the years for which births by maternal age were available (1940–2008). Death certificate data for persons with Down syndrome were available for the years 1968–2007. We estimated the number of people with Down syndrome on January 1, 2008, using a life table approach based on proportions of deaths by age. Monte Carlo sampling was used to create 90% uncertainty intervals (UIs) for our estimates. Results We estimated the January 1, 2008, population prevalence of Down syndrome as approximately 250 700 (90% UI, 185 900–321 700) based on proportions of deaths by age from the most recent 2 years (2006–2007) of death certificate data. This estimate corresponds to a prevalence of 8.27 people with Down syndrome per 10 000 population (90% UI, 6.14–10.62). Conclusion Our estimate of Down syndrome prevalence is roughly 25%–40% lower than estimates based solely on current birth prevalence. The results presented here can be considered a starting point for facilitating policy and services planning for persons with Down syndrome.

Background & Aims Although childhood and adult abuse are more prevalent among patients with irritable bowel syndrome (IBS) than healthy individuals (controls), other types of early adverse life events (EALs) have not been well characterized. We investigated whether different types of EALs, before an age of 18 years, are more prevalent among patients with IBS, and the effects of gender and non-gastrointestinal symptoms on the relationship between EALs and IBS. Methods EALs were evaluated in 294 IBS patients (79% women) and 435 controls (77% women) using the early trauma inventory self report form, which delineates sub-categories of general trauma and physical, emotional, and sexual abuse. Validated questionnaires assessed gastrointestinal, psychological, and somatic symptoms. Results Compared to controls, IBS patients reported a higher prevalence of general trauma (78.5% vs 62.3%), physical punishment (60.6% vs 49.2%), emotional abuse (54.9% vs 27.0%), and sexual events (31.2% vs 17.9%) (all P’s <.001). These significant differences were mainly observed in women. Of the EAL domains, emotional abuse was the strongest predictor of IBS (P<.001). Eight of the 27 EAL items were significant (P<.001) and increased the odds of having IBS by 108%–305%. Although EAL and psychological variables were related, EALs had an independent association with IBS (P=.04). Conclusion Various types of EALs are associated with development of IBS—particularly among women. Psychological distress and somatic symptoms might contribute to this relationship. When appropriate, EALs and non-gastrointestinal symptoms should be assessed in IBS patients.

SUMMARY In mice, clonal tracking of hematopoietic stem cells has revealed variations in repopulation characteristics. However, it is unclear whether similar properties apply in primates. Here, we examined this issue through tracking of thousands of hematopoietic stem and progenitor cells (HSPCs) in rhesus macaques for up to 12 years. Approximately half of the clones analyzed contributed to long-term repopulation (over 3–10 years) and likely represent self-renewing hematopoietic stem cells (HSCs), while the remainder contributed primarily for the first year. The long-lived clones could be further subdivided into functional groups contributing primarily to myeloid, lymphoid or both lineages. Over time, the 4–10% of clones with robust dual lineage contribution predominated in repopulation capacity. HSPCs expressing a CCR5 shRNA transgene behaved similarly to controls. Our study therefore documents HSPC behavior in a clinically-relevant model over a long time frame, and provides a substantial system-level dataset that is a reference point for future work.

OBJECTIVES Low-grade colonic mucosal inflammation has been postulated to have an important role in the pathophysiology of irritable bowel syndrome (IBS). The objectives of this study were (i) to identify serum and tissue-based immunological and neuroendocrine markers associated with mucosal inflammation in male (M) and female (F) patients with non-post-infectious IBS (non-PI-IBS) compared with healthy controls and (ii) to assess possible correlations of such markers with IBS symptoms. METHODS Sigmoid mucosal biopsies were obtained from 45 Rome II positive IBS patients without a history of PI-IBS (26 F, 35.5% IBS-C, 33.3% IBS-D, 31.1% IBS-A/M) and 41 healthy controls (22 F) in order to measure immunological markers (serum cytokine levels, colonic mucosal mRNA levels of cytokines, mucosal immune cell counts) and neuroendocrine markers associated with mucosal inflammation (corticotropin releasing factor- and neurokinin (NK)-related ligands and receptors, enterochromaffin cells). Symptoms were measured using validated questionnaires. RESULTS Of all the serum and mucosal cytokines measured, only interleukin-10 (IL-10) mRNA expression showed a group difference, with female, but not male, patients showing lower levels compared with female controls (18.0 ± 2.9 vs. 29.5 ± 4.0, P = 0.006). Mucosal mRNA expression of NK-1 receptor was significantly lower (1.15 ± 0.19 vs. 2.66 ± 0.56, P = 0.008) in female, but not male, patients compared with healthy controls. No other significant differences were observed. CONCLUSIONS Immune cell counts and levels of cytokines and neuropeptides that are associated with inflammation were not significantly elevated in the colonic mucosa of non-PI-IBS patients, and did not correlate with symptoms. Thus, these findings do not support that colonic mucosal inflammation consistently has a primary role in these patients. However, the finding of decreased IL-10 mRNA expression may be a possible biomarker of IBS and warrants further investigation.