To identify the prevalence of chronic low back pain (CLBP) and examine factors associated with this condition in a Southern Brazilian adult population, a population-based cross-sectional study was conducted, including 3,182 subjects of both sexes, aged 20 years or over, living in the urban area of Pelotas, Rio Grande do Sul State. The questionnaire included socio-demographic, behavioral, and nutritional variables, as well as characterization of exposure to ergonomic factors in daily activities. CLBP prevalence was 4.2%. The variables sex, age, marital status, schooling, smoking, body mass index, working in a lying position, heavy physical work, and repetitive movements were associated with CLBP. Prevalence of CLBP is important as it limits normal activities and increases the use of health care services. There may be differences in the ergonomic risk factors for CLBP and low back pain in general.

This paper describes the main methodological aspects of a cohort study, with emphasis on its recent phases, which may be relevant to investigators planning to carry out similar studies. In 1993, a population based study was launched in Pelotas, Southern Brazil. All 5,249 newborns delivered in the city's hospitals were enrolled, and subsamples were visited at the ages of one, three and six months and of one and four years. In 2004-5 it was possible to trace 87.5% of the cohort at the age of 10-12 years. Sub-studies are addressing issues related to oral health, psychological development and mental health, body composition, and ethnography. Birth cohort studies are essential for investigating the early determinants of adult disease and nutritional status, yet few such studies are available from low and middle-income countries where these determinants may differ from those documented in more developed settings. Resumo

Background: Helicobacter pylori (Hp) infection is associated with several upper gastrointestinal disorders. Local data on the epidemiology of the infection are scarce in Brazil. The purpose of this study is to measure the prevalence rate and to explore the associated factors among the adult population living in Pelotas, a southern Brazilin city.

To assess the effectiveness on child growth and body composition of a supplementary feeding program (Milk Supplement Program), a prospective, controlled study was conducted in Northeast Brazil. When entering the Program, children from 10 municipalities with the highest coverage rates in the Program (intervention group) were compared to non-beneficiary children from 10 municipalities with the lowest coverage rates (control group). A total of 219 children aged 6-18 months were enrolled. At entry, both groups were comparable in terms of age, sex, and nutritional status. There were frequent gaps in delivery of the supplement, no extra milk was provided to siblings less than 5 years of age, intra-household redistribution of milk was high, and maternal compliance with recommendations was low. Adjusted analyses by multilevel modelling showed average changes in weight, length, weight-age and length-age Z-scores, and % body water (deuterium method), at 6 months, of 1.53kg, 6.34cm, 0.33, 0.05, and 1.11% respectively among supplemented children as compared to 1.54kg, 6.5cm, 0.26, 0.07, and 4.10% among controls, with no statistically significant difference between groups. Thus, the Program failed to compensate for nutritional deficiencies in undernourished children in Northeast Brazil.

Objective: To investigate the association between Helicobacter pylori infection and anaemia. Design: Six cross-sectional studies. H. pylori infection was assessed by the [ 13 C]urea breath test using MS or IR analysis. Hb was measured for all countries. Ferritin and transferrin receptors were measured for Argentina, Bolivia, Mexico, and Venezuela. Setting: Health services in Argentina, Brazil and Mexico or public schools in Bolivia, Cuba and Venezuela. Subjects: In Argentina, 307 children aged 4-17 years referred to a gastroenterology unit; in Bolivia, 424 randomly selected schoolchildren aged 5-8 years; in Brazil, 1007 adults (157 men, 850 women) aged 18-45 years attending thirty-one primary healthcare units; in Cuba, 996 randomly selected schoolchildren aged 6-14 years; in Mexico, seventy-one pregnant women in their first trimester attending public health clinics; in Venezuela, 418 children aged 4-13 years attending public schools. Results: The lowest prevalence of H. pylori found was among children in Argentina (25?1 %) and the highest in Bolivia (74?0 %). In Bolivia, Cuba and Venezuela children showed similar prevalence of H. pylori infection as in Brazilian and Mexican adults (range 47?5 % to 81?8 %). Overall anaemia prevalence was 11?3 % in Argentina, 15?4 % in Bolivia, 20?6 % in Brazil, 10?5 % in Cuba and 8?9 % in Venezuela. Adjusted analyses allowing for confounding variables showed no association between H. pylori colonization and anaemia in any study. Hb, ferritin and transferrin receptor levels were also not associated with H. pylori infection in any country.