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Jan Burema

Publications and source records attributed to Jan Burema.

4 recordsLinked to original sources

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren.

The effect of iron fortification is generally assumed to be less than iron supplementation; however, the magnitude of difference in effects is not known. The present study aims to compare the efficacy of these two strategies on anaemia and iron status. After screening on low Hb, 425 anaemic children in six primary schools in Tam Nong district of Phu Tho province were included in a randomized, placebo-controlled trial comparing two groups receiving iron fortified instant noodles or iron supplementation for 6 months and a control group, with children in all groups having been dewormed. Blood samples were collected before and after intervention for haemoglobin, serum ferritin (SF), serum transferrin receptor (TfR), C-reactive protein (CRP), and haemoglobinopathies analysis. Regression analysis was used to assess the effect of iron fortification and iron supplementation on haemoglobin concentration, SF, TfR, body iron, and anaemic status as outcome variables. The improvement of haemoglobin, SF, and body iron level in the group receiving iron fortification was 42% (2.6 g/L versus 6.2 g/L), 20% (23.5 microg/L versus 117.3 microg/L), and 31.3% (1.4 mg/kg versus 4.4 mg/kg) of that in the iron supplementation group. The prevalence of anaemia dropped to 15.1% in the control group, with an additional reduction of anaemia of 8.5% in the iron supplementation group. The additional reduction due to iron fortification was 5.4%, which amounts to well over 50% of the impact of supplementation. In conclusion, the efficacy of iron fortification based on reduction of prevalence of anaemia, and on the change in haemoglobin level, is about half of the maximum impact of supplementation in case of optimal compliance. Thus, in a population of anaemic children with mild iron deficiency, iron fortification should be the preferred strategy to combat anaemia.

Anemia, Iron-Deficiency↗

The intraclass correlation coefficient applied for evaluation of data correction, labeling methods, and rectal biopsy sampling in DNA microarray experiments.

We show that the intraclass correlation coefficient (ICC) can be used as a relatively simple statistical measure to assess methodological and biological variation in DNA microarray analysis. The ICC is a measure that determines the reproducibility of a variable, which can easily be calculated from an ANOVA table. It is based on the assessment of both systematic deviation and random variation, and it facilitates comparison of multiple samples at once. We used the ICC first to optimize our microarray data normalization method and found that the use of median values instead of mean values improves data correction. Then the reproducibility of different labeling methods was evaluated, and labeling by indirect fluorescent dye incorporation appeared to be more reproducible than direct labeling. Finally, we determined optimal biopsy sampling by analyzing overall variation in gene expression. The variation in gene expression of rectal biopsies within persons decreased when two biopsies were taken instead of one, but it did not considerably improve when more than two biopsies were taken from one person, indicating that it is sufficient to use two biopsies per person for DNA microarray analysis under our experimental conditions. To optimize the accuracy of the microarray data, biopsies from at least six different persons should be used per group.

Analysis of Variance↗

Dietary quality and lifestyle factors in relation to 10-year mortality in older Europeans: the SENECA study.

The single and combined effects of three healthy lifestyle behaviors-nonsmoking, being physically active, and having a high-quality diet-on survival were investigated among older people in the SENECA Study. This European longitudinal study started with baseline measurements in 1988-1989 and lasted until April 30, 1999. The study population consisted of 631 men and 650 women aged 70-75 years from Belgium, Denmark, Italy, The Netherlands, Portugal, Spain, and Switzerland. A lifestyle score was calculated by adding the scores of the lifestyle factors physical activity, dietary quality, and smoking habits. The single lifestyle factors and the lifestyle score were related to mortality. Even at ages 70-75 years, the unhealthy lifestyle behaviors smoking, having a low-quality diet, and being physically inactive were singly related to an increased mortality risk (hazard ratios ranged from 1.2 to 2.1). The risk of death was further increased for all combinations of two unhealthy lifestyle behaviors. Finally, men and women with all three unhealthy lifestyle behaviors had a three- to fourfold increase in mortality risk. These results underscore the importance of a healthy lifestyle, including multiple lifestyle factors, and the maintenance of it with advancing age.

Age Distribution↗