The associations that income, education, and ethnicity have with birthweight and prematurity: how close are they?

OBJECTIVES: To identify evidence that income, education, or ethnicity might be associated with low birthweight, small-for-gestational-age birth, or preterm birth. METHODS: A systematic review was conducted using searches in two online databases, PubMed and Literature in the Health Sciences in Latin America and the Caribbean (LILACS). The searches covered materials published between 1 January 1982 and 5 May 2016. The search terms used were ("infant, premature" OR "infant, small for gestational age" OR "fetal growth retardation") AND ("socioeconomic factors" OR "ethnic groups" OR "maternal age"). RESULTS: A total of 3 070 references that met the initial selection criteria were analyzed, and 157 relevant studies were fully read. We located 18 studies that investigated associations of family or maternal income, education, or ethnicity with low birthweight, small-for-gestational-age birth, or preterm birth. Of the 18, 10 of them involved high-income countries, and 8 dealt with middle- or low-income countries. Greater evidence was found for an association between ethnicity and the three outcomes studied, particularly for prematurity among children of black mothers. There was little evidence for an association between maternal/family income or education and any of the three outcomes. CONCLUSIONS: Income and education weren't determinants for low birthweight, small-for-gestational-age birth, or preterm birth. However, black ethnicity was strongly associated with the three outcomes, especially with prematurity.

Viral load and genotypes of noroviruses in symptomatic and asymptomatic children in Southeastern Brazil.

BACKGROUND: Noroviruses (NoVs) are a major etiological agent of sporadic acute gastroenteritis worldwide. OBJECTIVES: To detect, quantify and characterize genogroups and genotypes of NoVs in children with and without gastrointestinal symptoms. STUDY DESIGN: NoVs were investigated by RT-PCR in a total of 319 fecal specimens from children up to three years old with (n=229) and without (n=90) acute diarrhea, between February 2003 and June 2004 in the emergency room in Vitória, Southeastern Brazil. NoVs were quantified by real-time PCR and genotyped. RESULTS: NoVs were detected in 17% (40/229) and 13% (12/90) of symptomatic and asymptomatic children, respectively. Six NoV-rotavirus A mixed infections were observed. Fifty-one strains were characterized as NoV GII and one as GI. Twenty strains were characterized as GII/4 (9/13), GII/3 (1/13), GII/6 (2/13) and GII/14 (1/13) in symptomatic and GII/3 (6/7) and GII/8 (1/7) in asymptomatic children. The median RNA viral loads were 8.39 and 7.15log(10)copies/g of fecal specimens for symptomatic and asymptomatic children, respectively (p=0.011). NoV load was lower when it was present in a mixed infection with rotavirus A (p=0.0005). CONCLUSIONS: This study demonstrates a diversity of NoV strains circulating in this geographic area, and reports GII/8 and GII/14 in the American Continent for the first time. In addition, it confirms GII/4 as the most prevalent genotype in symptomatic children and identified GII/3 in an important frequency, especially in asymptomatic children. Furthermore, preliminary results show that symptomatic patients present a viral load that is significantly greater than asymptomatic children (p=0.011).