Effect of zinc supplementation on the morbidity, immune function, and growth of low-birth-weight, full-term infants in northeast Brazil.

In Brazil, the highest incidence of low birth weight (LBW) occurs in the northeast, and diarrhea and respiratory infections are the main causes of infant mortality and morbidity. We hypothesized that LBW infants may be zinc deficient, and that this might be adversely affecting their immune function, morbidity, and postnatal growth. We therefore examined the effect of zinc supplementation on these outcomes during the first 6 mo of life. LBW full-term infants (mean birth weight 2337 g) were given daily for 8 wk either 5 mg Zn (n = 71), 1 mg Zn (n = 68), or a placebo (n = 66). Morbidity was determined prospectively through daily home visits (except on Sunday) during weeks 0-8, then twice weekly in weeks 9-26. Anthropometric measurements were made at 0, 4, 8, 17, and 26 wk. Immune function was assessed at 8 wk by the phytohemagglutinin skin test. Supplementation (5 mg Zn) was associated with a 28% reduction in diarrhea prevalence over the 6-mo period [after adjustment for confounders (P = 0.043)], and a 33% reduction in the prevalence of cough (NS, adjusted prevalence P = 0.073). All infants had a positive immune response at 8 wk. Although supplementation had no significant effect on weight and length gains from 0 to 26 wk, infants given 5 mg Zn gained more weight than infants given placebo during weeks 17-26 (P = 0.024, analysis of variance). There was no effect on any outcome with 1 mg Zn. We conclude that 5 mg Zn/d is of benefit to LBW, full-term infants who only have a modest weight deficit.

Breast-feeding and growth in Brazilian infants.

A new international growth reference is being prepared based on children who are fed according to World Health Organization recommendations, which entail exclusive breast-feeding for the first 4-6 mo of life. However, the number of exclusively breast-fed infants in most societies is small, so that selection biases may result from using such a population. We examined the variability in linear and soft tissue growth of infants according to their feeding patterns, emphasizing differences between exclusively and predominantly (breast milk plus fluids) breast-fed infants. About 650 infants from a relatively developed urban area in southern Brazil were examined at the ages of 1, 3, 6, and 12 mo, and an additional 800 infants at 6 and 12 mo. At each visit, infants were weighed and measured and a 24-h dietary recall was completed with the infants' caretakers. In the analyses of growth, care was taken to address the biases of reverse causality, regression to the mean, and confounding. There was little association between feeding pattern and growth in the first month. From 1 to 3 mo, partially breast-fed infants tended to gain more weight, followed by those who were completely weaned. From 3 to 6 mo, fully weaned infants grew fastest in weight and length and exclusively breast-fed infants grew slowest. After 6 mo of age, the growth in length of partially breast-fed and fully weaned infants was similar, but the latter gained more weight. There were virtually no differences between exclusively and predominantly breast-fed infants in the first 6 mo of life. There results suggest that both of these groups may be pooled for the purpose of constructing growth references.

PIP: Under the auspices of the World Health Organization, a new international growth reference is being developed to reflect the growth of breast-fed infants and their tendency to falter from 3-4 months onward. Of concern, however, is the small number of exclusively breast-fed infants in most societies and the potential for selection bias. A study conducted in Brazil in 1993 found no significant differences between exclusively and predominantly breast-fed infants in the first 6 months of life, suggesting that both these groups can be pooled for the purpose of growth reference construction. 650 infants from a relatively developed urban area in southern Brazil (Pelotas) were examined at 1, 3, 6, and 12 months of age and an additional 800 infants were enrolled at 6 and 12 months. There was little association between growth and feeding pattern in the first month of life. Slower growth in the first month increased the risk of subsequent weaning. From months 1-3, partially breast-fed infants tended to gain more weight, followed by those who were completely weaned. During months 3-6, fully weaned infants grew fastest in terms of both weight and length and exclusively breast-fed infants grew slowest. After 6 months of age, the growth in length of partially breast-fed and fully weaned infants was similar, but the latter group gained more weight. The tendency for breast-fed infants to grow more slowly should be considered in view of the many benefits of breast feeding, including protection against infections and diseases of the immune system, psychological advantages, and birth spacing.

Vitamin A supplementation and childhood malaria in northern Ghana.

Two companion, randomized, placebo-controlled trials of prophylactic vitamin A supplementation provided the opportunity to assess the impact of supplementation on malaria parasitemia, morbidity, and mortality in young children in northern Ghana. In the mortality study, 21,906 children were visited every 4 mo over 2 y, and in the morbidity study 1455 children were visited weekly for 1 y. There was no difference between children supplemented with vitamin A and those given placebo in malaria mortality rates (rate ratio = 1.03; 95% CI 0.74, 1.43) or fever incidence based on reported symptoms. Malaria parasitemia rates, parasite densities in children with a positive blood smear, and rates of probable malaria illness also did not differ between treatment groups. There was no correlation between serum retinol at the beginning of the trial and subsequent malaria parasitemia in children who received placebo (r = 0.01). It is concluded that vitamin A supplementation had no impact on malaria in this population.

Vitamin A supplementation, morbidity, and serum acute-phase proteins in young Ghanaian children.

The association of vitamin A supplementation with concentrations of positive acute-phase proteins in the serum was investigated in the Child Health Study of the Ghana Vitamin A Supplementation Trials, a randomized, controlled trial of the effect of vitamin A on morbidity in children aged < 5 y. Mean serum concentrations of alpha 1-acid glycoprotein, serum amyloid A, and C-reactive protein did not differ overall between the vitamin A-supplemented and placebo-treated groups. Treatment groups were then subdivided according to what symptoms children had experienced in the week before blood sampling. Acute-phase-protein responses to fever and cough were not affected by vitamin A supplementation. There was a tendency for vitamin A-supplemented children, but not placebo children, to have elevated acute-phase proteins in association with reported vomiting or severe diarrhea. The failure of unsupplemented children to mount an acute-phase response may have contributed to their increased morbidity from gastrointestinal symptoms.

Precision, accuracy, and reliability of hemoglobin assessment with use of capillary blood.

BACKGROUND: Previous research has suggested that there may be significant within-subject variability, both site-to-site and over time, in hemoglobin concentrations in capillary blood. OBJECTIVE: This study examined the reliability of the portable hemoglobinometer (PHM) system with use of capillary blood and the implications of errors of the magnitude found for the classification of anemia status in individuals and population groups. The precision and accuracy of the method with use of venous blood were also tested. DESIGN: Three empirical data sets were used to measure reliability, precision, and accuracy of the PHM system [2 from Honduras (n = 87 and 141); 1 from Bangladesh (n = 73)]. Simulation data were used to assess the implications of errors for screening individuals for anemia and to estimate anemia prevalence. RESULTS: High within-subject variability (unreliability) was identified when capillary blood from the left hand was compared with that from the right hand (CV: 6.3%) and when measurements were taken on 4 consecutive days (CV: 7.0%). Reliability was only 69% and 50%, respectively. Precision and accuracy, however, were very high (concordance coefficients of 0.99 and 0.98 and CV < 1%). CONCLUSIONS: The simulation data showed that errors of the magnitude found due to unreliability can lead to misclassification of anemia status in individuals and small biases in anemia prevalence estimates. We recommend replicate sampling to reduce the influence of unreliability in the use of the PHM system with capillary blood.

Effect of vitamin A supplementation on the growth of young children in northern Ghana.

The effect of prophylactic vitamin A supplementation on child growth was studies in two randomized, placebo-controlled trials carried out in adjacent areas of northern Ghana between 1989 and 1991. In the Health Study, the midupper arm circumference (MUAC) and weight of the approximately 1500 children (aged 6-59 mo) in the trial were measured every 4 wk for up to 52 wk. In addition, MUAC, weight, and height were measured at each of the four potential vitamin A or placebo dosing times, which were at 4-mo intervals. In the Survival Study, MUAC and weight were measured at 4-mo intervals at each of seven dosing rounds in the approximately 15 000 children currently in the trial. Overall, there were > 90 000 observations of weight and MUAC in > 25 000 children, and 3347 observations of length/height in 1546 children. Within each study, the mean monthly weight, MUAC, and gains in length/height in each treatment group were compared by using multilevel modeling. There were no significant differences in either MUAC or gains in length/height. The only significant difference in weight gain was in the Survival Study: children in the vitamin A-supplemented group who were > or = 36 mo of age had a mean weight gain that was 3 g lower per month (95% CI: 0.4, 5.0, P = 0.02) than that in the placebo group; a difference that was unlikely to be functionally important in this age group. Vitamin A supplementation did not lead to any increased growth in this population of young children, in whom supplementation reduced mortality and severe morbidity substantially.

Influence of morbidity on serum retinol of children in a community-based study in northern Ghana.

Serum retinol concentrations decrease during illness and thus may not accurately reflect the vitamin A status of populations with a high prevalence of illness. To quantify the contribution of illness to low serum retinol in a field study of children aged 6-59 mo in northern Ghana, serum retinol values were compared with two indicators of recent illness; symptoms reported by parents and acute-phase protein concentrations in serum. Serum retinol was not associated with symptoms of illness but showed a significant negative correlation with both alpha 1-acid glycoprotein (AGP) and serum amyloid A (SAA). Elevated AGP was associated with a 24% decrease in mean serum retinol. A large proportion of asymptomatic children had elevated AGP or SAA concentrations, suggesting that subclinical infections may have had important effects on serum retinol. A significant negative correlation between malaria parasite density and serum retinol indicated that malaria may have been one of the subclinical infections responsible. Measurement of AGP may improve interpretation of serum retinol data from populations with a high prevalence of morbidity.

Particulate air pollution and respiratory disease in Anchorage, Alaska.

This paper examines the associations between average daily particulate matter less than 10 microns in diameter (PM10) and temperature with daily outpatient visits for respiratory disease including asthma, bronchitis, and upper respiratory illness in Anchorage, Alaska, where there are few industrial sources of air pollution. In Anchorage, PM10 is composed primarily of earth crustal material and volcanic ash. Carbon monoxide is measured only during the winter months. The number of outpatients visits for respiratory diagnoses during the period 1 May 1992 to 1 March 1994 were derived from medical insurance claims for state and municipal employees and their dependents covered by Aetna insurance. The data were filtered to reduce seasonal trends and serial autocorrelation and adjusted for day of the week. The results show that an increase of 10 micrograms/m3 in PM10 resulted in a 3-6% increase in visits for asthma and a 1-3% increase in visits for upper respiratory diseases. Winter CO concentrations were significantly associated with bronchitis and upper respiratory illness, but not with asthma. Winter CO was highly correlated with automobile exhaust emissions. These findings are consistent with the results of previous studies of particulate pollution in other urban areas and provide evidence that the coarse fraction of PM10 may affect the health of working people.

Influence of heavy agricultural work during pregnancy on birthweight in northeast Brazil.

BACKGROUND: Women in developing countries often continue their agricultural work during late pregnancy. Whether this adversely affects birthweight is not clear from previous studies as few controlled for confounding factors. This study seeks to clarify this issue. METHODS: This retrospective cohort study investigated 958 low-income women and their singleton newborn babies residing in a region of Northeast Brazil dependent on sugar-cane production. Women were recruited at maternity centres, when attending for delivery, and were allocated to one of two groups according to their exposure to heavy agricultural labour for at least 3 months during the second and third trimesters of pregnancy (n = 250), or to household activities only (n = 708). RESULTS: The mean birthweight of infants born to women who worked in agriculture during 9 months of pregnancy was 190 g lower than that of the non-exposed group (P = 0.02). After controlling for confounding factors, the adjusted effect was 117 g (P = 0.05). Heavy agricultural work for 6, 7 or 8 months had no significant effect. CONCLUSIONS: These findings suggest that working throughout pregnancy significantly reduces birthweight in this low-income population.

Diarrhoea--defining the episode.

BACKGROUND: There is still no consensus on the appropriate definition of an 'episode' of diarrhoea, even though it has been shown that the choice of definition has a major impact on reported incidence rates. Previous work has focused on the observed distribution of illness episodes in time but has not attempted to determine whether the patterns observed depart from those expected by chance. METHODS: A simple theoretical model of the distribution of illness episodes is developed, based on the concept of a 'trigger event'. The model incorporates elements relating to the duration of symptoms, inter-individual variation in incidence rates and seasonality. Appropriate parameters for the model are derived from two empirical datasets. RESULTS: It is shown that short intervals between one aetiologically distinct period of diarrhoea and the next will frequently occur by chance, especially in circumstances where high incidence rates and within-child clustering of illness prevail. The duration of symptoms will have no effect on the length of intervals between periods of illness, and seasonality is unlikely to have a major impact. Over 10% of all non-initial trigger events might be expected to occur during the course of a pre-existing period of diarrhoea, and would not therefore be identified in a study based on reported symptoms. CONCLUSIONS: The findings of previous studies, suggesting that 2 or 3 days without symptoms will generally mark a new episode of diarrhoea, are endorsed. Modelling the expected distribution of illness in time may help to highlight structural or analytical problems with empirical datasets.

Length and ponderal index at birth: associations with mortality, hospitalizations, development and post-natal growth in Brazilian infants.

BACKGROUND: Low birthweight infants suffer greater mortality and neonatal morbidity, grow less well in infancy and show poorer psycho-motor development. However, this simple categorization may obscure important differences in aetiology and prognosis between infants born stunted, thin, or both. METHODS: In 1993, all births in Pelotas, Brazil, were enrolled into a prospective study of health and development in infancy. Of 5249 live births, 5160 had length and weight measures at birth, and were classified into tertiles of length and ponderal index. All deaths and hospitalizations were monitored, and suspected developmental delay and attained growth at 12 months were assessed on a subsample of 1364 infants. Logistic regression was used to control for gestational age and socioeconomic status. RESULTS: There was no association between birth length and ponderal index tertiles. After adjusting for gestational age, infants in the lower tertiles of both length and ponderal index presented a 3.8-times higher risk of mortality from day 8 to day 365, and a 2.5-times higher risk of hospitalization compared to infants with greater birth lengths and/or ponderal indices. Suspected developmental delay was associated with length and, less strongly, with ponderal index, but there was no synergism between the two. Infants in the middle and upper tertiles of ponderal index at birth became thinner. CONCLUSIONS: Birth length was strongly associated with development at 12 months, but only infants born both short and thin were at increased risk of mortality and hospitalizations. The combination of the two measures provides a useful classification of the anthropometric status of the newborn.

PIP: A prospective study of all 5249 live births in Pelotas, Brazil, in 1993 examined interactions between health and development in infancy. The 5160 infants who had length and weight measurements taken at birth were classified into tertiles of length-for-age Z score and ponderal index--a measure of soft tissue growth. There was no association between these two measures. After adjustments for gestational age, infants in the lower tertiles of both length and ponderal index had a 3.8 times greater risk of mortality from day 8 to 365 and a 2.5 times higher risk of hospitalization than infants in the high tertile. However, infants born short but not thin, or thin but not short, were not at increased risk of either mortality or hospitalization. Suspected developmental delay at 12 months was associated with shorter stature at birth and, less strongly, with a lower ponderal index, but there was no synergism between the two measures. Infants in the middle and upper tertiles of ponderal index at birth became markedly thinner in the first year of life, while length changes were less strongly associated with initial status. Overall, these findings suggest that the combination of length and ponderal index at birth may provide a functionally relevant means of classifying the newborn's anthropometric status since the two measures are relatively independent of each other at the level of the individual and appear to affect different aspects of the infant's subsequent health and development.

Validity of rapid estimates of household wealth and income for health surveys in rural Africa.

STUDY OBJECTIVE: To test the validity of proxy measures of household wealth and income that can be readily implemented in health surveys in rural Africa. DESIGN: Data are drawn from four different integrated household surveys. The assumptions underlying the choice of wealth proxy are described, and correlations with the true value are assessed in two different settings. The expenditure proxy is developed and then tested for replicability in two independent datasets representing the same population. SETTING: Rural areas of Mali, Malawi, and Côte d'Ivoire (two national surveys). PARTICIPANTS: Random sample of rural households in each setting (n=275, 707, 910, and 856, respectively). MAIN RESULTS: In both Mali and Malawi, the wealth proxy correlated highly (r>/=0.74) with the more complex monetary value method. For rural areas of Côte d'Ivoire, it was possible to generate a list of just 10 expenditure items, the values of which when summed correlated highly with expenditures on all items combined (r=0.74, development dataset, r=0. 72, validation dataset). Total household expenditure is an accepted alternative to household income in developing country settings. CONCLUSIONS: It is feasible to approximate both household wealth and expenditures in rural African settings without dramatically lengthening questionnaires that have a primary focus on health outcomes.

Patterns of malaria morbidity and mortality in children in northern Ghana.

A malaria prevalence survey was carried out in young children in northern Ghana between October 1990 and September 1991, in an area with continuous mortality and morbidity surveillance. There was marked seasonal variation in malaria deaths, reported fevers, parasite rates and mean parasite densities, with parasite rates reaching 85-94% in the wet season. The monthly numbers of malaria deaths were highly correlated with rainfall in the previous 2 months (r = 0.90, P < 0.001). Parasite rates were highest in the oldest children (5-7 years), but parasite densities and rates of febrile illness were highest in those 6-11 months old. Haemoglobin levels were also at their lowest in this age group. The predominant species, Plasmodium falciparum, was present in 71% of all blood films. Febrile illness was well recognized by mothers, but it was not possible to construct a simple clinical diagnostic algorithm which would identify even 50% of children with high levels of malaria parasitaemia (> or = 4000 parasites/microL). Malariometric indicators appear to have changed little in this area since a previous survey in 1955.

People and eyes: statistical approaches in ophthalmology.

In conclusion, when an observation by its nature involves two eyes, as for blindness, statistical analyses should be conducted on individuals rather than eyes and between eye correlation is not a problem. In other circumstances, if information on only one eye per individual is used in the analysis there is a potential "waste" of information leading to less precise estimates of effect and less power. In addition, bias may be introduced into a study if there is non-random selection of the eye for inclusion in the analysis. The use of an overall summary of ocular findings for an individual may result in "wastage" of information in a similar fashion to the use of only one eye per individual. On the other hand, an analysis of individual eyes with no allowance made for between eye correlation may result in falsely narrow confidence intervals around estimates of effect. Between eyes correlation may be assessed empirically using the kappa statistic or similar means. If between eye correlation is substantial, statistical techniques exist which can utilise all available data while allowing for the correlation. In some circumstances a powerful design may be to use the fellow eye as a "control". Two conclusions may be drawn from this review of analytical approaches to the analysis of clinical data in the BJO. Firstly, the analytical approaches employed in many studies fail to use all the data available. In other words the analysis is less than "optimal". Secondly, in a proportion of studies, inappropriate statistical methods are used which may lead the investigator to draw inappropriate conclusions. In other words, the analysis is invalid. Ophthalmic data, by their very nature, present particular statistical challenges. We emphasise the need to involve appropriate statistical expertise in the design and analysis of ophthalmic studies.

Feeding behaviors, food attitudes, and body fatness in infants.

One hundred and thirty-four infants were studied at 3 and 9 months of age to determine possible behavioral causes of fatness. A feeding behaviors interview and a semantic differential to measure mothers' attitudes toward food were developed. A stepwise multiple regression procedure revealed that none of the independent variables significantly predicted the dependent variable of infant triceps skinfold thickness at the age of 9 months. Even so, care should be exercised in instructing caregivers concerning specific feeding behaviors to use with infants.

Zinc supplementation, mental development and behaviour in low birth weight term infants in northeast Brazil.

OBJECTIVE: To test whether zinc supplementation reduces the deficits in mental development and behaviour that are found in term infants of low birth weight in the study population. DESIGN: A prospective double-blind, part-randomised efficacy trial. SETTING: A low-income population in Pernambuco, northeast Brazil, where the economy is largely dependent on sugar-cane production, and where over 90% of deliveries occur in health facilities. SUBJECTS: During a 20-month period, all singleton, term infants weighing 1500-2499 g born to families of low income ( < US $280/month) were enrolled at birth (n = 205). At 6 and 12-months, the numbers tested were 163 and 138 respectively. INTERVENTION: Infants born from January 1993-January 1994 were randomly assigned to receive daily, except Sundays, a placebo (n = 66) or 1 mg zinc (n = 68). Those born February-August 1994 were given 5 mg zinc (n = 71). Supplementation was for eight weeks, starting at birth. Field workers visited each infant at home to administer the supplement. RESULTS: At 6 and 12-months, mental and psychomotor development was assessed with the Bayley Scales of Infant Development and no significant differences in the scores of the three groups were found. At 12-months, behaviour was also assessed on 5 ratings. Ratings were highest in infants given 5 mg zinc (P = 0.042). CONCLUSIONS: Zinc supplementation (5 mg/d) for eight weeks may reverse some of the poor behaviours, particularly responsiveness, exhibited by low birth weight infants. No amelioration of their mental and psychomotor deficits was found.

PIP: Severe zinc deficiency, widespread in developing countries, has been associated with cognitive and psychomotor impairment in animal studies. The capability of zinc supplementation, to reduce the deficits in mental development and behavior found in low-birth-weight term infants, was assessed in a prospective study conducted in a low-income community in Pernambuco, Brazil. All 205 singleton, term infants, delivered at the local hospital in a 20-month period and weighing 1500-2499 g at birth, were enrolled. Infants born from January 1993 to January 1994, were randomly assigned to receive either a placebo (n = 66) or 1 mg of zinc (n = 68) 6 days a week. The 71 low-birth-weight infants delivered from February to August 1994, were given 5 mg of zinc 6 days a week. Supplementation administered by local health workers was initiated at birth and lasted for 8 weeks. Mental and psychomotor development was measured at 6 and 12 months of age by the Bayley Scales of Infant Development. There were no significant differences between infants in the 3 study groups on this test. Also at 12 months, infant behavior was assessed on 5 scales. Ratings for one of these scales (responsiveness to tester) were significantly higher in infants who received 5 mg of zinc than in the 2 other groups, and the 5 mg zinc group also had the highest scores on the 4 other scales. Further studies are urged to investigate the effect of zinc provided later in life, and for longer periods of time, on the development of low-birth-weight infants.

Lack of association between vitamin A status and measures of conjunctival epithelial integrity in young children in northern Ghana.

OBJECTIVE: To investigate the association between vitamin A status and conjunctival epithelial function in young children in rural northern Ghana and to consider whether impaired epithelial function was associated with increased measures of systemic infection in these children. DESIGN: Children were selected from the Ghana Vitamin A Supplementation Trials' Child Health Study, a randomized, double-blind, placebo-controlled trial of the effect of vitamin A supplementation on morbidity. Treatment group and serum retinol concentrations were used as measures of vitamin A status, conjunctival impression cytology and tear IgA concentrations as measures of conjunctival epithelial integrity, and serum immunoglobulin and alpha 1-acid glycoprotein concentrations as indicators of chronic or acute systemic infection. SUBJECTS: Children 13-64 months old. INTERVENTION: 60 mg retinol as retinyl palmitate every 4 months for 1 year. RESULTS: Vitamin A status was not significantly associated with epithelial integrity nor with measures of systemic infection. Impaired conjunctival epithelial integrity was also not associated with increased systemic infection. CONCLUSIONS: There was no evidence for a major role of improved epithelial integrity and function on the biochemical indices of chronic or acute systemic infection after vitamin A supplementation. These data support the observations in the main study that vitamin A supplementation did not improve conjunctival impression cytology nor decrease the prevalence of most morbidity symptoms.

PIP: Vitamin A deficiency is associated with an increased risk of mortality among young children. The authors report findings from their study of whether vitamin A deficiency was associated with epithelial defects which might result in impaired mucosal protection and increased systemic infection in children. Samples and data were used from the Ghana Vitamin A Supplementation Trials' Child Health Study, a randomized, double-blind, placebo-controlled study of the effect of periodic large doses of vitamin A on the morbidity of young children. 80 children aged 13-64 months in rural northern Ghana received 60 mg retinol as retinyl palmitate every four months for one year. The study found vitamin A status to be significantly associated with neither epithelial integrity nor measures of systemic infection. Impaired conjunctival epithelial integrity was also not associated with increased systemic infection. These data support observations in the broader study that vitamin A supplementation does not improve conjunctival impression cytology or decrease the prevalence of most morbidity symptoms.

Associations between respiratory illness and PM10 air pollution.

In this study, the association between daily morbidity and respirable particulate pollution (i.e., particles with a mass median aerodynamic diameter of < or = 10 microns [PM10]) was evaluated in the general population of Anchorage, Alaska. Using insurance claims data for state employees and their dependents who lived in Anchorage, Alaska, the authors determined the number of medical visits for asthma, bronchitis, and upper respiratory infections. The number of visits were related to the level of particulate pollution in ambient air measured at air-monitoring sites. This study was conducted during a 3-y period, which included several weeks of higher-level particulate pollution that resulted from a volcanic eruption (i.e., August 1992). The particulate pollution was measured by the Anderson head sampler (24-h accumulation). The medical visits of the population at risk were also tallied daily. To help confirm whether PM10 exposure was a risk factor in the exacerbation of asthma, we used a regression analysis to regress daily asthma visits on PM10 pollution levels, controlling for seasonal variability. A significant positive association between morbidity and PM10 pollution was observed. The strongest association was with concurrent-day PM10 levels. The relative risk of morbidity was higher with respect to PM10 pollution during warmer days.

Randomised, double blind, placebo controlled clinical trial of efficacy of vitamin A treatment in non-measles childhood pneumonia.

OBJECTIVE: To evaluate the impact on clinical recovery and severity of the addition of large doses of vitamin A to the standard treatment for childhood pneumonia. DESIGN: A randomised, double blind, placebo controlled trial. SETTING: Study children were recruited at a public hospital in Recife, north east Brazil, an area of marginal vitamin A deficiency. SUBJECTS: 472 children aged 6 to 59 months with clinical diagnosis of pneumonia. INTERVENTIONS: 200,000 IU (infants) or 400,000 IU (1-4 year olds) of vitamin A in oil or similar capsules of placebo divided into two daily oral doses, in addition to the standard treatment. MAIN OUTCOME MEASURES: Duration of the episode and incidence of adverse outcomes. RESULTS: The groups were similar with respect to overall duration of pneumonia and incidence of adverse outcomes. Children who received vitamin A, however, were less likely to have fever by day 3 (P = 0.008) and were 29% less likely to fail to respond to the first line antibiotic (P = 0.054). CONCLUSION: There was little evidence for an effect of vitamin A treatment on the immediate outcome of the pneumonia episode.

[Nutritional and feeding status of preschool children in the semi-arid region of Bahia (Brazil): I. Anthropometric assessment]. / Situação nutricional e alimentar de pré-escolares no semi-árido da Bahia (Brasil): I. Avaliação antropométrica.

A survey of 754 preschool children was undertaken in the urban areas of seven small towns of the semi-arid region of Bahia, Northeast Brazil. The study set out to determine the prevalence of weight and height deficits, as well as to correlate them with variables such as age, family income, mother's schooling and food consumption. A prevalence of 22.9% of Height for Age (HA) below -2.0 SD was found (stunting) and prevalence of 19.1% and 3.6% were determined, respectively for Weight for Age (WA) and Weight for Height (WH) below -2.0 SD (wasting). Regarding food consumption, only 6.8% of the children received a diet with an adequate energy supply for their age group in the previous day. There was a close association between inadequate HA and WA and family income per capita (p = 0.001 and p = 0.000, respectively). Children from families with income < 1/4 of the minimum wage per capita had twice the chance of being malnourished as compared with those from the > or = 1/2 minimum wage per capita stratum. The children included in this study showed prevalences of inadequate WH and WA significantly higher than those found in a national survey conducted in the same period (p = 0.047 and p = 0.000 respectively). This fact is surprising since in the last decade important reductions in child malnutrition and mortality were reported in the country as a whole; this may indicate that children from this region probably were not benefitted in the same way as the rest of the Brazilian child population.