Purpose-Interest in the eVects of neighbourhood or local area social characteristics on health has increased in recent years, but to date the existing evidence has not been systematically reviewed. Multilevel or contextual analyses of social factors and health represent a possible reconciliation between two divergent epidemiological paradigms-individual risk factor epidemiology and an ecological approach. Data sources-Keyword searching of Index Medicus (Medline) and additional references from retrieved articles. Study selection-All original studies of the eVect of local area social characteristics on individual health outcomes, adjusted for individual socioeconomic status, published in English before 1 June 1998 and focused on populations in developed countries. Data synthesis-The methodological challenges posed by the design and interpretation of multilevel studies of local area eVects are discussed and results summarised with reference to type of health outcome. All but two of the 25 reviewed studies reported a statistically significant association between at least one measure of social environment and a health outcome (contextual eVect), after adjusting for individual level socioeconomic status (compositional eVect). Contextual eVects were generally modest and much smaller than compositional eVects. Conclusions-The evidence for modest neighbourhood eVects on health is fairly consistent despite heterogeneity of study designs, substitution of local area measures for neighbourhood measures and probable measurement error. By drawing public health attention to the health risks associated with the social structure and ecology of neighbourhoods, innovative approaches to community level interventions may ensue. (J Epidemiol Community Health 2001;55:111-122)

Among children, having health insurance is strongly associated with access to primary care. The new children's health insurance program enacted as part of the Balanced Budget Act of 1997 may substantially improve access to and use of primary care by children.

Postpartum maternity leave may have a positive effect on breastfeeding among full-time workers, particularly those who hold nonmanagerial positions, lack job flexibility, or experience psychosocial distress. Pediatricians should encourage patients to take maternity leave and advocate for extending paid postpartum leave and flexibility in working conditions for breastfeeding women.

In 2012, the Accreditation Council for Graduate Medical Education (ACGME) designated ultrasound (US) as one of 23 milestone competencies for emergency medicine (EM) residency graduates. With increasing scrutiny of medical educational programs and their effect on patient safety and health care delivery, it is imperative to ensure that US training and competency assessment is standardized. In 2011, a multiorganizational committee composed of representatives from the Council of Emergency Medicine Residency Directors (CORD), the Academy of Emergency Ultrasound of the Society for Academic Emergency Medicine (SAEM), the Ultrasound Section of the American College of Emergency Physicians (ACEM), and the Emergency Medicine Residents' Association was formed to suggest standards for resident emergency ultrasound (EUS) competency assessment and to write a document that addresses the ACGME milestones. This article contains a historical perspective on resident training in EUS and a table of core skills deemed to be a minimum standard for the graduating EM resident. A survey summary of focused EUS education in EM residencies is described, as well as a suggestion for structuring education in residency. Finally, adjuncts to a quantitative measurement of resident competency for EUS are offered. 1 Soon thereafter, the Society for Academic Emergency Medicine (SAEM) endorsed this position and recommended the development of a training curriculum.2 In 1994, Mateer and colleagues 3 published the model curriculum for physician training in EUS and by 1996 the EM core content curriculum required EUS competency for residency graduates. A landmark resolution by the American Medical Association in 1999 (Resolution 802 and policy H-230.960) stated that ultrasound (US) is "within the scope of practice of appropriately trained physicians" and that each specialty should decide the necessary training requirements for sonography competency.4 ACEP further developed the standard recognition of EUS as "a skill integral to the practice of EM" in the 2001 Model of the Clinical Practice of Emergency Medicine (EM Model), which resulted in the Accreditation Council for Graduate Medical Education (ACGME) mandating that all EM residents attain competency in the use of EUS by the completion of residency training. 5 In 2008, as an update and revision, ACEP published more comprehensive specialty-specific guidelines as a standard for EUS.6 Subsequently, SAEM, the Council of Emergency Medicine

In addition to individual socioeconomic characteristics, living in neighborhoods that are less socioeconomically advantaged may differentially influence birthweight, depending on women's ethnicity and nativity.