The impact on vitamin A status of the distribution of vitamin A during national immunisation days (NIDs) has not been well established despite strong promotion by international agencies and donors. Using a pre–post design, the change in prevalence of vitamin A deficiency was examined in pre-school children in Mali.

Two cross-sectional surveys were conducted in Mopti region, the first in March 1997 before this strategy was adopted and the second in March 1999, four-and-a-half months after a mass distribution of vitamin A during NIDs.

We compared the vitamin A status of children aged 12 to 66 months targeted in 1999 by NIDs with the status of children in the same age group in 1997. Infectious events of the previous two weeks were concurrently recorded. Within the 1999 sample, the status of recipient and non-recipient children was also compared.

In 1997, the prevalence of xerophthalmia (defined by the presence of night blindness and/or Bitot spots) was 6.9% (95% confidence interval (CI) 5.1–9.2) and the modified retinol dose response (MRDR) test proved abnormal in 77.8% of 12–66-month-old children (95% CI 68.27–85.17). In 1999 this picture had improved significantly, both for xerophthalmia prevalence, 3.3% (95% CI 2.1–5.2), and abnormal MRDR test response, 63.1% (95% CI 54.25–71.23). The infectious morbidity rates between 1997 and 1999 tended to decrease. No significant improvement was found among children older than those targeted by NIDs. In 1999, children who received vitamin A had a lower risk for xerophthalmia (3.0% for recipients vs. 8.7% for non-recipients) and experienced fewer infectious events.

The clinical and biological vitamin A status of pre-school children improved between 1997 and 1999. Mass distribution of vitamin A appears to reduce the occurrence of xerophthalmia and would seem to be associated with a decrease in other related illnesses. Vitamin A supplementation during NIDs should be given a high priority when vitamin A deficiency remains a public health problem.

Objective: To estimate the role of human milk n-6 and n-3 polyunsaturated fatty acids (PUFA) in term infant growth in two African urban populations.

Observational study. Weight gains at 5 months of age and dietary habits were compared between Congolese infants (n=102) and Burkinabè infants (n=101). Socio-economic status and anthropometry of the mothers were also recorded.

One suburban district in Brazzaville (capital of The Congo) and one in Ouagadougou (capital of Burkina Faso).

Two random samples of nursing mothers and their 5-month-old infants.

All infants were born at term and there was no difference in birth weights. At 5 months of age, infants in Ouagadougou were thinner but not shorter than their counterparts in Brazzaville (average weight gain (standard deviation): 614 (168) g month-1 vs. 720 (176) g month-1; P>0.0001). Drastic differences were found in infant diets with regard to extra fluid intake and n-6 and n-3 PUFA concentrations in breast milk. In Ouagadougou, all infants were given fluids other than milk from birth. Breast milk had highly unbalanced 18:2n-6/18:3n-3 and n-6/n-3 long-chain PUFA ratios (53:1 and 5:1, respectively). In Brazzaville, half of the infants received fluids other than milk, and breast milk showed balanced 18:2n-6/18:3n-3 and n-6/n-3 long-chain PUFA ratios (12:1 and 1:1, respectively). A non-linear relationship between 18:2n-6/18:3n-3 ratio and growth was established in Brazzaville (P=0.0027). The 18:2n-6/18:3n-3 ratio adjusted with covariates had an even more significant effect on weight gain (P=0.0011). Applying the same model in Ouagadougou did not show such a relation.

Data strongly suggest that a balanced ratio of 18:2n-6/18:3n-3 (between 5:1 and 15:1) in breast milk leads to higher weight gain of infants during the first 5 months of life.

To assess the effect of the incorporation of amylase in maize-based flours prepared as gruels on the energy intake and growth of Congolese infants.

A randomised controlled trial. At 18 weeks of age, infants were randomised into either an intervention group, where they were provided with a maize/soya-based flour that contained amylase, or a control group, where they were provided with a similar flour that did not contain amylase.

Urban borough of Poto-Poto in Brazzaville, The Congo.

Eighty infants (40 in each group) were randomised into intervention and control groups. Three infants in the intervention group and two controls subsequently dropped out.

At 24 weeks, the addition of amylase resulted in a significant increase in energy intake (in kJ kg-1 day-1) from gruels (P=0.02) without affecting breast milk consumption. In contrast, total energy intake (in kJ kg-1 day-1) did not differ significantly between groups (P=0.08). After adjustment for morbidity and previous growth, infants in the intervention group showed better growth in length during the trial (+0.22 cm month-1; P=0.04), especially between 24 and 31 weeks of age (+0.51 cm month-1; P>0.01). There were no differences in weight velocity between groups.

The findings of this study suggest that the consumption of amylase-treated gruels allows an increase in energy intake from these gruels without affecting breast milk consumption but has no impact on total daily energy intake. However, if started after 6 months, it could be effective in preventing faltering of infant linear growth.

To describe the lifestyle characteristics and nutrient intakes of the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).

Cohort of men and women recruited through general practices or by post to include a high proportion of non meat-eaters. Dietary, anthropometric and lifestyle data were collected at baseline and four diet groups were defined.

United Kingdom.

In total, 65 429 men and women aged 20 to 97 years, comprising 33 883 meat-eaters, 10 110 fish-eaters, 18 840 lacto-ovo vegetarians and 2596 vegans.

Nutrient intakes and lifestyle factors differed across the diet groups, with striking differences between meat-eaters and vegans, and fish-eaters and vegetarians usually having intermediate values. Mean fat intake in each diet group was below the UK dietary reference value of 33% of total energy intake. The mean intake of saturated fatty acids in vegans was approximately 5% of energy, less than half the mean intake among meat-eaters (10–11%). Vegans had the highest intakes of fibre, vitamin B1, folate, vitamin C, vitamin E, magnesium and iron, and the lowest intakes of retinol, vitamin B12, vitamin D, calcium and zinc.

The EPIC–Oxford cohort includes 31 546 non meat-eaters and is one of the largest studies of vegetarians in the world. The average nutrient intakes in the whole cohort are close to those currently recommended for good health. Comparisons of the diet groups show wide ranges in the intakes of major nutrients such as saturated fat and dietary fibre. Such variation should increase the ability of the study to detect associations of diet with major cancers and causes of death.

This study investigated 5-year trends in body weight, overweight and obesity and their association with sociodemographic variables in a large, multi-ethnic community sample of Australian adults.

This prospective population study used baseline and 5-year follow-up data from participants in the Melbourne Collaborative Cohort Study (MCCS).

Population study in Melbourne, Australia.

In total, 12 125 men and 17 674 women aged 35–69 years at baseline.

Mean 5-year weight change in this sample was +1.58 (standard deviation (SD) 4.82) kg for men and +2.42 (SD 5.17) kg for women. Younger (35–44 years) men and, in particular, women gained more weight than older adults and were at highest risk of major weight gain (≥5 kg) and becoming overweight. Risk of major weight gain and associations between demographic variables and weight change did not vary greatly by ethnicity. Education level showed complex associations with weight outcomes that differed by sex and ethnicity. Multivariate analyses showed that, among men, higher initial body weight was associated with decreased likelihood of major weight gain, whereas among women, those initially overweight or obese were about 20% more likely to experience major weight gain than underweight or healthy weight women.

Findings of widespread weight gain across this entire population sample, and particularly among younger women and women who were already overweight, are a cause for alarm. The prevention of weight gain and obesity across the entire population should be an urgent public health priority. Young-to-mid adulthood appears to be a critical time to intervene to prevent future weight gain.

To describe how a risk analysis can be applied to food fortification, with emphasis on voluntary fortification and intake levels that might exceed usual dietary levels.

Use of the risk analysis model as a frame to classify nutrients according to the risk of exceeding upper safe intake levels. Furthermore, to apply the model when discussing possible consequences of liberal fortification practices on eating behaviour and disease patterns.

The discussion on food fortification presently going on internationally.

Micronutrients can be classified according to their safety margin, i.e. the size of the interval between the recommended intake and the upper safe level of intake. We suggest that nutrients with a small safety margin, i.e. for which the upper safe level is less than five times the recommended intake, be placed in a category A and should be handled with care (retinol, vitamin D, niacin, folate and all minerals). Category B comprises nutrients with an intermediate safety margin (vitamins E, B6, B12 and C), while nutrients that according to present knowledge are harmless even at 100 times the recommendation (vitamin K, thiamin, riboflavin, pantothenic acid and biotin) are categorised as C.

The risk analysis model is a useful tool when assessing the risk of both too low and excess intakes of single micronutrients, but can also be applied to analyse the consequences of fortification practices on eating behaviour and disease patterns. Liberal fortification regulations may, for example, distort the conception of what is healthy food, and drive consumption towards a more unhealthy diet, contributing to the plague of overweight and concomitant increased risk of degenerative diseases.

The impact of fortification practices on the total eating pattern of a population should become an integrated part of the discussions and regulations connected to the issue.

The European Youth Heart Study (EYHS) is a cross-sectional, school-based population study on risk factors for future cardiovascular disease in children, with an overall participation rate in Sweden of about 50%. To study the representativeness of the participants in the Swedish part of EYHS, a comprehensive non-participant follow-up study was carried out.

A structured multilevel analysis model was developed, addressing each level in the sampling procedure. The income, educational and occupational categories of the geographical regions of the study (level I), school catchment areas (level II) and parents (level III) were compared with official data. Participating and non-participating pupils (level IV) were compared through a questionnaire.

Thirty-seven state schools in two regions of Central Sweden (Örebro and southern Stockholm) were visited during the school year 1998/1999.

Boys and girls aged 9 and 15 years were randomly sampled through a multiphase sampling procedure.

Data for socio-economic status for levels I and II corresponded well to national and regional official data. At level III, non-manually working parents were slightly over-represented among parents of participating children. At level IV, non-participating subjects corresponded in most respects to participants with a few exceptions – mainly more interest in physical exercise among participants.

Based on the knowledge from the non-participant study, we do not foresee problems regarding interpretation of the outcomes in the EYHS, despite the low participation rate.

To examine a possible problem of overreporting and to describe the degree of error with the International Physical Activity Questionnaire (IPAQ) short telephone protocol.

Cross-sectional study, using two different physical activity (PA) self-report protocols.

Telephone interviews about PA in Belgium.

Fifty adults who had previously been interviewed with IPAQ in a national survey.

Seventy-five per cent reported less PA with the modified procedure than with the IPAQ. Twenty-three of the 50 individuals were found to have reported some amounts of PA with the IPAQ (either walking, or vigorous or moderate PA) when they should have reported none. In total, based on their revised reports of PA, 50% fewer persons met PA recommendations than was the case with IPAQ. The overreporting could not be related to types of error-prone individuals.

Overreporting of PA in population samples is a serious problem that could be reduced by implementing procedure changes without changing the IPAQ items themselves.

To calculate the sensitivity, specificity and agreement of body mass index (BMI) values proposed by Cole et al. (Br. Med. J. 2000; 320: 1) and Must et al. (Am. J. Clin. Nutr. 1991; 53: 839 & 54: 773) with weight-for-height index in the nutritional evaluation of children.

Criterion standards for diagnostic tests.

North-east and south-east Brazil.

Two thousand nine hundred and twenty children studied in Life Pattern Research performed by the Brazilian Institute of Geography and Statistics in 1997. Main outcome measures are the sensitivity, specificity and agreement of BMI values proposed by Must et al. (1991) and Cole et al. (2000).

Sensitivity of values proposed by both authors was around 90%. Specificity was almost 100% considering weight-for-height index as the gold standard. The agreement of both values with weight-for-height index, based on kappa results, was good and in pre-school children it was excellent.

Values proposed by Cole et al. (2000) and Must et al. (1991) should be used carefully to screen obesity in childhood but can be used to ‘diagnose’ overweight children with a very low chance of having false-positive results. Although the values proposed by both authors performed similarly, use of Cole et al.'s values should be encouraged. The latter cover children from 2 to 6 years old; their values are presented for six-month age intervals; they are based on a larger sample from six different countries; and they are related to the definition of adult obesity.

To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR).

Subjects completed the Scottish Collaborative Group FFQ and carried out a 4-day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients, the percentages of subjects classified into the same and opposite thirds of intake, and Cohen's weighted kappa.

Forty-one men, mean age 36 (range 21-56) years, and 40 women, mean age 33 (range 19-58) years, recruited from different locations in Aberdeen, Scotland.

Spearman correlation coefficients tended to be lower than Pearson correlation coefficients, and were above 0.5 for 10 of the 27 nutrients in men and 17 of the 27 nutrients in women. For nutrients with Spearman correlation coefficients above 0.5, the percentage of subjects correctly classified into thirds ranged from 39 to 78%, and weighted kappa values ranged from 0.23 to 0.66.

Both Spearman correlation coefficients and weighted kappa values are useful in assessing the relative validity of estimates of nutrient intake by FFQs. Spearman correlation coefficients above 0.5, more than 50% of subjects correctly classified and less than 10% of subjects grossly misclassified into thirds, and weighted kappa values above 0.4 are recommended for nutrients of interest in epidemiological studies.