Body mass index trend as a new parameter for evaluating children's nutritional status.

OBJECTIVES: The objective was to identify a body mass index (BMI) trend as a new indicator and predictor of children's nutritional status, replacing absolute BMI, and to demonstrate that a local BMI trend is more appropriate for this purpose than a national (or international) BMI trend. STUDY DESIGN: An entire school year group of primary school children were subject to a longitudinal 8-year cohort study. METHODS: BMI was measured three times during primary school education-on enrolment to primary school, then in the fifth and eighth grades. The BMI values obtained were used to create gender- and age-based percentile curves for children born in 1998/1999 (Osijek Percentile Curves (OPC) study) in the Osijek-Baranja County, Croatia. Every BMI result obtained was linked to one of the five percentile ranks (PRs) according to threshold percentiles 3, 10, 90 and 97; hence, the PRs were <3, ≥3 to <10, ≥10 to <90, ≥90 to <97 and ≥ 97. Percentiles and PRs were specified for each BMI value in a dual fashion, i.e. according to OPC and the entire Croatian territory (Croatian Percentile Curves (CROPC)-2008) cross-sectional study. After integrating the BMI values at all three time points, two BMI trends appeared-one based on the OPC criteria and one based on the CROPC-2008 criteria. Individual trends were grouped into three descriptive BMI categories: 'healthy', 'at risk' and 'unhealthy'. RESULTS: For the OPC and CROPC-2008, the 'healthy' trend characterised 2097 (78.72%) and 1975 (74.14%) children, respectively; the 'at risk' trend marked 434 (16.29%) and 458 (17.19%) children, respectively; and the 'unhealthy' trend was found in 133 (4.99%) and 231 (8.67%) children, respectively. The biggest difference between the OPC-based and CROPC-2008-based results was detected in the 'unhealthy' trend. According to CROPC-2008, there were almost twice as many children in that category. For the purpose of study design and comparing results obtained based on OPC and those obtained based on CROPC-2008, the BMI of one boy was used. His BMI values on starting primary school, in the 5th and in the 8th grades were 19.05 kg/m2, 26.11 kg/m2 and 27.11 kg/m2, respectively. Analysis of PRs based on OPC and CROPC-2008 reveals that the same boy was represented by different trends: '<90 <90 <97' and '<90 <97 <97', respectively. In terms of residence, girls from urban areas have higher BMI values than rural girls when starting primary school. CONCLUSION: This study suggests that a BMI trend could be a better indicator and predictor of children's nutritional status than absolute BMI. In addition, a cohort study is preferential to a cross-sectional study as a trend in an OPC-based study can be personalised. Also, local BMI reference values defined for each generation of children are more advantageous in this context than national BMI reference values.

Hepatitis B in the family.

During a 3-year period (1992-1995), 239 index cases of hepatitis B virus (HBV) infection and 459 members of their households from the Osijek-Baranja county were examined. The aim of the study was to determine the spread of HBV infection in the families with a member verified as a virus carrier, and to identify the family members with the highest risk of infection according to kinship degrees. The retrospective and prospective methods were used in the study. The probable route of infection was assessed by the use of an epidemiologic questionnaire, and the serologic status of the study subjects concerning infection with HBV was determined by enzyme immunoassays (HBsAg, anti-HBs, anti-HBe and anti-HBc). The first member of a family identified as a virus carrier was considered an index case. HBV infection was demonstrated in 334 (47.85%) out of a total of 698 subjects. Only 21 (6.28%) of the 334 subjects with verified HBV infection developed the clinical picture of acute hepatitis B. The ratio of clinically manifest vs inapparent infection was 1:16. Serologic traces of infection were detected in 95 of the 459 family members of the index cases, yielding a mean rate of the infection among the virus carrier family members of 20.70%.