Determinants of aggressive and prosocial behaviour among Jamaican schoolboys.

PURPOSE: This study examines risk factors for aggression among boys in Kingston, Jamaica. METHODS: One hundred and one aggressive and 101 prosocial schoolboys in grades 5-6 (mean age 11.7, SD 0.6 years) were selected by peer and teacher ratings from 10 schools in the capital city, Kingston, during 1998. They were given in-depth questionnaires, arithmetic, reading and verbal intelligence tests and their behaviour was rated. Their parents were also given a detailed questionnaire. RESULTS: The aggressive boys reported significantly more involvement in fights than the prosocial boys. They had lower scores on spelling/reading and verbal IQ, less ambitious aspirations and poorer quality school uniforms. They were not more likely to infer hostile intent in ambiguous situations but were more likely to respond with aggression. Aggressive boys came from poorer homes with more marijuana use, less parental affection or supervision and more family discord. They were less exposed to religious instruction, their parents had lower occupational levels and were more likely to be in common-law unions than married. They were more exposed to neighbourhood violence and were punished more often at home and at school. Logistic regression analyses were carried out to determine the independent risk factors for aggression. Exposure to neighbourhood violence, physical punishment at home and family discord were associated with increased risk; parents' being married, practising religion as a family and better school uniforms were associated with reduced risk. CONCLUSIONS: Although community violence was a serious problem, family characteristics were also important risk factors for aggressive behaviour.

Determinants of aggressive and prosocial behaviour among Jamaican schoolboys / Determinantes del comportamiento agresivo y prosocial entre los escolares Jamaicanos)

PURPOSE: This study examines risk factors for aggression among boys in Kingston, Jamaica. METHODS: One hundred and one aggressive and 101 prosocial schoolboys in grades 5-6 (mean age 11.7, SD 0.6 years) were selected by peer and teacher ratings from 10 schools in the capital city, Kingston, during 1998. They were given in-depth questionnaires, arithmetic, reading and verbal intelligence tests and their behaviour was rated. Their parents were also given a detailed questionnaire. RESULTS: The aggressive boys reported significantly more involvement in fights than the prosocial boys. They had lower scores on spelling/reading and verbal IQ, less ambitious aspirations and poorer quality school uniforms. They were not more likely to infer hostile intent in ambiguous situations but were more likely to respond with aggression. Aggressive boys came from poorer homes with more marijuana use, less parental affection or supervision and more family discord. They were less exposed to religious instruction, their parents had lower occupational levels and were more likely to be in common-law unions than married. They were more exposed to neighbourhood violence and were punished more often at home and at school. Logistic regression analyses were carried out to determine the independent risk factors for aggression. Exposure to neighbourhood violence, physical punishment at home and family discord were associated with increased risk; parents' being married, practising religion as a family and better school uniforms were associated with reduced risk. CONCLUSIONS: Although community violence was a serious problem, family characteristics were also important risk factors for aggressive behaviour.

Propósito: Este estudio examina los factores de riesgo que influyen en la agresión entre los niños en Kingston, Jamaica. Métodos: Ciento un escolares agresivos y 101 escolares prosociales en los grados 5­6 (edad promedio 11.7, desviación estándard 0.6 años) fueron seleccionados de acuerdo con las valoraciones de los pares y los maestros de 10 escuelas en la ciudad capital, Kingston, durante 1998. Se les aplicó cuestionarios exhaustivos, así como pruebas de aritmética y lectura, tests de inteligencia, y se clasificó su conducta. A sus padres también se les aplicó un cuestionario detallado. Resultados: Los niños agresivos reportaron una participación en peleas significativamente mayor que los niños prosociales. Asimismo, tuvieron puntuaciones más bajas en deletreo, lectura y coeficiente de inteligencia (C.I.) verbal, mostraron tener aspiraciones menos ambiciosas, y vestían uniformes más pobres. No estaban más inclinados a inferir intenciones hostiles en situaciones ambiguas, pero si más propensos a responder agresivamente. Los niños agresivos provenían de hogares más pobres, caracterizados por mayor consumo de marihuana, menos afecto o supervisión por parte de los padres, y más discordia en la familia. Estaban también menos expuestos a la instrucción religiosa, sus padres tenían bajo nivel ocupacional, y vivían en su mayor parte más en unión consensual que en matrimonio. Estaban más expuestos a la violencia del vecindario, y recibían castigos en la casa y la escuela con mayor frecuencia. Se llevaron a cabo análisis de regresión logística a fin de determinar los factores de riesgo de la agresión. La exposición a la violencia del vecindario, el castigo físico en el hogar, y la discordia familiar estaban asociados con el aumento del riesgo. En cambio, padres casados en matrimonio, la práctica de la religión como familia, y mejores uniformes escolares, estuvieron asociados con la reducción del riesgo. Conclusiones. Aunque la violencia comunitaria constituía un serio problema, las características de la familia fueron también importantes factores de riesgo en el comportamiento agresivo.

Factors associated with size and proportionality at birth in term Jamaican infants.

The objective of this study was to identify the factors associated with size and proportionality at birth in a cohort of term infants established to investigate their growth and development. One hundred and forty term low-birth-weight (birth-weight < 2,500 g) infants and 94 normal birth-weight infants (2,500- < 4,000 g) were recruited within 48 hours of birth at the main maternity hospital, Kingston, Jamaica. Birth anthropometry and gestational age were measured, and maternal information was obtained by interview and from hospital records. Controlling for gestational age, variables independently associated with birth-weight were rate of weight gain in the second half of pregnancy, maternal height, haemoglobin level < 9.5 microg/dL, time of first attendance in antenatal clinic, birth order, pre-eclampsia, and consumption of alcohol, with 33% of the variance in birth-weight explained. Birth length was associated only with maternal height and age, while measures of proportionality (ponderal index and head/length ratio) were associated with characteristics of the environment in late pregnancy, including rate of weight gain, weight in late pregnancy, and pre-eclampsia. The variation in maternal characteristics associated with size or proportionality at birth may reflect the times during gestation when different aspects of growth are most affected.

Early linear growth retardation and later blood pressure.

OBJECTIVE: To examine the effects of stunting in early childhood on blood pressure in later childhood. DESIGN: A cohort study. SETTING: Kingston, Jamaica. SUBJECTS: Seven to eight year old children, 120 stunted (height for age <-2 s.d. of the NCHS references) and 224 non-stunted (height for age >-1 s.d. of the NCHS references) at age 9-24 months. METHODS: Stunted and non-stunted children were identified at age 9-24 months by house to-house survey of poor neighbourhoods in Kingston, Jamaica. Blood pressure and anthropometry were measured at age 7-8 y. Birth weight was obtained from hospital records (73%) or maternal recall. RESULTS: The stunted children remained shorter and thinner than the non-stunted ones. In multiple regression analysis adjusting for size and pulse rate, the stunted children had higher systolic blood pressure (P<0.05). Birth weight was not a significant predictor of systolic blood pressure. CONCLUSION: Stunting in early childhood may increase the risk of elevated systolic blood pressure in later life. SPONSORSHIP: Nutricia Research Foundation, The Netherlands and the Commonwealth Caribbean Medical Research Council.

Effects of growth restriction in early childhood on growth, IQ, and cognition at age 11 to 12 years and the benefits of nutritional supplementation and psychosocial stimulation.

OBJECTIVES: (1) To determine whether benefits to growth and cognition remain after intervention in growth-restricted children who received psychosocial stimulation and nutritional supplementation in early childhood. (2) To investigate the extent of the differences in IQ and cognition at age 11 to 12 years between growth-restricted and non-growth-restricted children. STUDY DESIGN: Growth-restricted and non-growth-restricted children were identified at age 9 to 24 months, at which time the growth-restricted children participated in a 2-year randomized trial of nutritional supplementation and psychosocial stimulation. Eight years after the interventions ended, the children's growth, IQ, and cognitive functions were measured. RESULTS: There were no significant benefits from supplementation to growth or cognition. Children who had received stimulation had higher scores on the Weschler Intelligence Scales for Children-Revised full-scale (IQ) and verbal scale and tests of vocabulary and reasoning (all P <.05). The growth-restricted children had significantly lower scores than the non-growth-restricted children on 10 of 11 cognitive tests. CONCLUSIONS: Psychosocial stimulation had small but significant long-term benefits on cognition in growth-restricted children. Growth-restricted children had significantly poorer performance than non-growth-restricted children on a wide range of cognitive tests, supporting the conclusion that growth restriction has long-term functional consequences.

Effect of breastfeeding and morbidity on the development of low birthweight term babies in Brazil.

Low birthweight (LBW) occurs in 17% of births in developing countries and many of them are full term. The subsequent development of LBW term infants is poorer than higher birthweight children and more likely to be affected by poor social circumstances. We investigated the effects of morbidity and breastfeeding on the development of these LBW term infants. Two parallel cohorts (n = 131 + 131) of LBW term (1500-2499 g) and higher birthweight (3000-3499 g) infants were recruited from six maternity centers in northeast Brazil. The longitudinal prevalence of morbidity and the frequency of breastfeeding over the first 6 mo of life were assessed. The infants' development was assessed on the Bayley Scales at 6 and 12 mo, and we previously reported that the low birthweight group had lower scores than the higher birthweight group. Hospitalizations in the first 6 mo were negatively associated with 6-mo and 12-mo Bayley scores in both groups. Among LBW infants, but not higher birthweight infants, there were significant associations between the prevalence of diarrhea and mental and motor development at 6 mo and mental development at 12 mo. Breastfeeding frequency in the first 4 wk of life was positively associated with mental development in both birthweight groups at 6 mo but not at 12 mo. Breastfeeding beyond 4 wk was not associated with the children's development. We conclude that low birthweight infants are especially vulnerable to the effects of diarrhea, and the greater frequency and differential effect of diarrhea partly explains their poorer development.

Behaviour and development of stunted and nonstunted Jamaican children.

In order to examine the mechanism whereby stunted children have poor developmental levels, we compared the behaviour of stunted (N = 78) and nonstunted (N = 26) children aged 12 to 24 months, and examined the relationship of their behaviour to their developmental levels. The effect of nutritional supplementation with or without psychosocial stimulation on the stunted children's behaviour was also examined. The children were observed at home during 4 days over a period of 6 months. The stunted children showed significantly more apathy, and less enthusiasm and variety in exploring, were less happy and more fussy. Caretakers' vocalisations to them were less warm or instructive. Stunted children's activity level, exploratory and happy behaviours were predictive of change in developmental levels measured on the Griffiths Scales, from enrolment to 12 and 24 months later. Supplementation predicted mental age at 12 and 24 months after enrolment, however, it had no significant effect on behaviour.

Nutrition and education: a randomized trial of the effects of breakfast in rural primary school children.

Hunger during school may prevent children in developing countries from benefiting from education. Although many countries have implemented school feeding programs, few programs have been rigorously evaluated. We conducted a randomized, controlled trial of giving breakfast to undernourished and adequately nourished children. The undernourished group comprised 407 children in grades 2-5 in 16 rural Jamaican schools (weights-for-age < or = -1 SD of the National Center for Health Statistics references) and the adequately nourished group comprised 407 children matched for school and class (weights-for-age >-1 SD). Both groups were stratified by class and school, then randomly assigned to breakfast or control groups. After the initial measurements, breakfast was provided every school day for 1 school year. Children in the control group were given one-quarter of an orange and the same amount of attention as children in the breakfast group. All children had their heights and weights measured and were given the Wide Range Achievement Test before and after the intervention. School attendance was taken from the schools' registers. Compared with the control group, height, weight, and attendance improved significantly in the breakfast group. Both groups made poor progress in Wide Range Achievement Test scores. Younger children in the breakfast group improved in arithmetic. There was no effect of nutritional group on the response to breakfast. In conclusion, the provision of a school breakfast produced small benefits in children's nutritional status, school attendance, and achievement. Greater improvements may occur in more undernourished populations; however, the massive problem of poor achievement levels requires integrated programs including health and educational inputs as well as school meals.

The development of low birth weight term infants and the effects of the environment in northeast Brazil.

OBJECTIVES: (1) To compare the mental and psychomotor development of low birth weight term (LBW-T) infants with that of appropriate birth weight (ABW) infants at 6 and 12 months of age. (2) To examine the relationship between developmental levels and social background. METHODS: A cohort of 131 LBW-T infants (1500 to 2499 gm) and 131 ABW infants (3000 to 3499 gm) matched for sex and time of birth, recruited from six maternity centers in Northeast Brazil were followed for 1 year. Their development was assessed with the Bayley Scales at 6 and 12 months of age, and at 12 months their behavior during the test was rated on five scales. Details of their families' socioeconomic status were recorded and the degree of stimulation in their homes was assessed. RESULTS: At 6 months of age the LBW-T infants had significantly lower scores than the ABW infants on the mental development index (MDI; 4.2 points lower, p < 0.001) and on the psychomotor development index (PDI; 7.3 points lower, p < 0.001). The difference had increased by 12 months of age (MDI 7.0 points lower, p < 0.001; PDI 9.9 points lower, p < 0.001). Socioeconomic variables were related to development at both ages in both groups. Maternal literacy was significantly related to the PDI in LBW-T infants at 12 months but not in ABW infants. Similarly, stimulation in the home was related to the MDI in LBW-T infants at 6 and 12 months but not in ABW infants. LBW-T infants were less active, cooperative, vocal, and happy, and were more inhibited than ABW infants. CONCLUSIONS: LBW-T infants had poorer development than ABW infants and differed in their behavior. There was an interaction between birth weight and the environment. LBW-T infants, but not ABW infants, were affected by the quality of stimulation in the home and maternal illiteracy.

Evaluation of school feeding programs: some Jamaican examples.

It is hypothesized that giving children a daily breakfast at school may improve their scholastic achievement through several mechanisms: increasing the time spent in school, improving certain cognitive functions and attention to tasks, and, perhaps indirectly, improving nutritional status. Two Jamaican studies showed that providing breakfast to students at school improved some cognitive functions, particularly in undernourished children. However, changes in classroom behavior varied depending on the quality of the school. Children in better-organized schools concentrated on tasks for longer periods and made fewer undesirable movements, whereas in poorly organized schools the children's behavior deteriorated. Studies to date have provided insufficient evidence to determine whether children's long-term scholastic achievement is improved by eating breakfast daily. Well-designed, randomized, controlled, long-term trials are essential for determining public policy on the implementation of school feeding programs.

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.

School performance in adolescent Jamaican girls: associations with health, social and behavioural characteristics, and risk factors for dropout.

Health, nutrition and behavioural determinants of school achievement, attendance and dropout were examined in 452 girls aged 13-14 years, randomly selected from grade 8 in nine schools in inner-city Kingston, Jamaica. Girls who were anaemic, sexually active or aggressive had worse achievement levels. Better achievement levels were associated with possession of school materials and access to reading material outside of school. Poor attendance, early sexual activity, and not living with both parents predicted school dropout in the subsequent year. Strategies to reduce anaemia, to improve sex education and reduce the levels of aggression may benefit school performance.

Small for gestational age, term babies, in the first six years of life.

The cognitive development and behaviour in the first six years of life of small for gestational age (SGA) babies born at term are reviewed. Differences in sample selection and confounding factors associated with socio-economic background, perinatal complications and biased follow-up make the interpretation of results and the comparison of studies difficult. Studies of infants (< 12 months) generally do not show any differences between SGA babies and controls. One study, carried out in Brazil and including comprehensive data on socio-economic background, parental literacy and infant stimulation, showed that low birth weight (LBW) babies were more vulnerable to effects of the environment than normal birth weight (NBW) babies, thus illustrating the importance of looking for interactions between covariates, rather than controlling for them. Deficits begin to appear in the second year of life, but are mainly found in high-risk subgroups. In all three studies of SGA children tested at 3 years of age, the SGA children had lower scores than NBW controls. SGA children tested between 4 and 7 years had generally lower scores than NBW, but differences were smaller and sometimes did no longer reach statistically significant levels. Some recommendations are made for future studies.

PIP: An estimated 16% of births worldwide are low birth weight (LBW); 90% of such infants are in developing, low-income countries. A greater proportion of LBW infants in low-income countries is reported to be small for gestational age (SGA) compared to in developed countries. The subsequent development of such children is critically important to both the future of the children and the countries they will inherit. Findings are reported from a review of the literature on the cognitive development and behavior during the first 6 years of life of SGA infants born at term. 6 studies were found of term, SGA infants in whom development was assessed during the first 2 years of life. Several of these studies followed the children beyond age 2 years and up to age 7. Differences in sample selection and confounding factors associated with socioeconomic background, perinatal complications, and biased follow-up complicate the interpretation of results and the comparison of studies. Nonetheless, the observed studies of infants under age 12 months generally show no differences between SGA subjects and controls. Deficits, however, in development begin to appear during the second year of life, but were found mainly in high-risk subgroups. In all 3 studies of SGA children tested at age 3 years, the SGA children had lower scores than did normal birth weight (NBW) controls. SGA children tested between ages 4 and 7 years had generally lower scores than NBW children, but differences were smaller and sometimes no longer statistically significant. One study conducted in Brazil is discussed in some detail.

Growth and development four years after treatment for the Trichuris dysentery syndrome.

A follow-up study is reported of 18 children 4 y after treatment for the Trichuris dysentery syndrome (TDS) and matched control children. The TDS children were initially severely stunted and had extremely low developmental levels. They showed catch-up in height of 1.9 z-scores even though they remained in very poor environments. Their intelligence quotients, school achievement and cognitive function remained significantly lower than those of the controls. Controlling for their earlier developmental levels, the TDS children showed a small improvement in mental development relative to the controls.

Schoolchildren's diets and participation in school feeding programmes in Jamaica.

OBJECTIVES: To describe food consumption during the school day of rural Jamaican children and participation in two government school feeding programmes. To determine factors which were related to these. DESIGN: Cross sectional. SETTING: 16 primary schools in rural Jamaica. SUBJECTS: 415 children in grades 2 and 5 (ages 7 and 10 years). RESULTS: Consumption of sweets, sweet drinks and snacks was high. Mean intakes at lunch were: energy 1537 kJ (SD 756), protein 10.4 g (SD 7.6) and iron 1.5 mg (SD 1.2). The mean energy intake was 17-20% of the daily requirement for this age group. Two types of school feeding programmes were available in the schools, one provided a cooked meal and the other a bun and milk. Median availability of school meals (as a percentage of children enrolled in the schools) over three terms was 24.6% (range 0-85.4%). Twenty per cent of the children participated in one or other programme. Poorer children were more likely to participate in the bun and milk programme (odds ratio 2.1, 95% CI 1.3-3.5) but children with more money to purchase food participated in the more costly cooked meal programme (odds ratio 2.4, 95% CI 1.3-4.6). CONCLUSIONS: Energy intakes at lunch in Jamaican children were somewhat below optimal levels and the reliance on sweets and snacks is an area of concern. Programme characteristics such as meal cost, may affect access to school feeding by poor children.

Nutrition, anaemia, geohelminth infection and school achievement in rural Jamaican primary school children.

OBJECTIVE: To determine whether nutritional status, anaemia and geohelminth infections were related to school achievement and attendance in Jamaican children. DESIGN: A cross-sectional study using a randomly selected sample. SUBJECTS: Eight hundred children aged 9-13 y randomly selected from those enrolled in grade 5 in 16 primary schools in rural Jamaica. RESULTS: The mean height-for-age of the children was -0.37 z-score +/- 1.0 s.d. with 4.9% having heights-for-age < -2 s.d. of the NCHS references. Anaemia (Hb < 11 g/dl) was present in 14.7% of the children, 38.3% were infected with Trichuris trichiura and 19.4% with Ascaris lumbricoides. Achievement levels on the Wide Range Achievement Test were low, with children performing at grade 3 level. In multilevel analyses, controlling for socioeconomic status, children with Trichuris infections had lower achievement levels than uninfected children in spelling, reading and arithmetic (P < 0.05). Children with Ascaris infections had lower scores in spelling and reading (P < 0.05) Height-for-age (P < 0.01) was positively associated with performance in arithmetic. Ascaris infection (P < 0.001) and anaemia (P < 0.01) predicted poorer school attendance. CONCLUSION: Despite mild levels, undernutrition and geohelminth infections were associated with achievement, suggesting that efforts to increase school achievement levels in developing countries should include strategies to improve the health and nutritional status of children.

PIP: The association of nutritional status, anemia, and geohelminth infection with school attendance and performance was investigated in a cross-sectional study of 800 primary school students 9-13 years of age (mean age, 10.8 years) from 4 rural parishes in Jamaica. 4.9% of the children had heights-for-age less than 2 standard deviations of the US National Center for Health Statistics references and 14.7% were anemic; 38.3% were infected with Trichuris trichiura and 19.4% with Ascaris lumbricoides. Multivariate analyses, controlled for socioeconomic status, indicated children with Trichuris infection had significantly lower achievement levels than uninfected children in spelling, reading, and arithmetic, while those with Ascaris infection had significantly lower scores in spelling and reading. Height-for-age was positively associated with performance in arithmetic. Ascaris infection and anemia predicted poorer school attendance. The associations demonstrated in this study are not necessarily causal. However, these findings indicate that efforts to increase school achievement levels in developing countries should include strategies to address the health and nutritional status of rural children.

Effects of early childhood supplementation with and without stimulation on later development in stunted Jamaican children.

It is not known whether nutritional supplementation in early childhood has long-term benefits on stunted children's mental development. We followed up 127 7-8-y old children who had been stunted in early childhood and received supplementation, stimulation, or both. At 9-24 mo of age, the children had been randomly assigned to four treatment groups: nutritional supplementation, stimulation, both treatments, and control. After 2 y, supplementation and stimulation had independent benefits on the children's development and the effects were additive. The group receiving both treatments caught up to a matched group of 32 nonstunted children. Four years after the end of the 2-y intervention 97% of the children were given a battery of cognitive function, school achievement, and fine motor tests. An additional 52 nonstunted children were included. Factor analyses of the test scores produced three factors: general cognitive, perceptual-motor, and memory. One, the perceptual-motor factor, showed a significant benefit from stimulation, and supplementation benefited only those children whose mothers had higher verbal intelligence quotients. However, each intervention group had higher scores than the control subjects on more tests than would be expected by chance (supplemented and both groups on 14 of 15 tests, P = 0.002; stimulated group in 13 of 15 tests, P = 0.01), suggesting a very small global benefit. There was no longer an additive effect of combined treatments at the end of the intervention. The stunted control group had significantly lower scores than the nonstunted children on most tests. Stunted children's heights and head circumferences on enrollment significantly predicted intelligence quotient at follow-up.

A method to estimate prevalence of iron deficiency and iron deficiency anemia in adolescent Jamaican girls.

A method is presented to estimate a cutoff for hemoglobin concentration appropriate for estimating the prevalence of iron deficiency anemia in poor Jamaican girls 13-14 y of age. Iron deficiency was determined from a three-variable model of iron status (serum ferritin, erythrocyte protoporphyrin, and mean corpuscular volume). The most appropriate hemoglobin cutoff was considered the one that minimized misclassification of iron deficiency: that yielding the maximum kappa coefficient for correctly classifying iron deficiency between 100 and 120 g/L, at 1-g/L intervals. By using this method, a hemoglobin cutoff of 107 g/L was considered most appropriate. This cutoff and the other indicators were used to estimate prevalence of iron deficiency and iron deficiency anemia in the Jamaican girls: 7.6% and 4.3%, respectively. This approach should be appropriate for determining hemoglobin cutoffs for iron deficiency anemia in other populations.

Early childhood supplementation does not benefit the long-term growth of stunted children in Jamaica.

The long-term benefits of early childhood supplementation and the extent to which catch-up growth occurs following linear growth retardation remain controversial. Stunted children (height-for-age < -2 SD of NCHS references, n = 122) recruited from a survey of poor neighborhoods in Kingston, Jamaica, participated in a 2-yr randomized, controlled trial of supplementation beginning at ages 9-24 mo. A group of 32 non-stunted children from the same neighborhoods was also followed. Four years after the intervention ended, when children were 7 to 8 y old, there were no effects of supplementation on any anthropometric measure. From the end of the trial until follow-up, the children who had been supplemented gained 1.2 cm less (P < 0.05) than the non-supplemented children, approximately the same amount as they had gained during the trial compared with the non-supplemented children. After adjustment for regression to the mean, the height-for-age of stunted children (supplemented and non-supplemented combined) increased from enrollment to follow-up by 0.31 Z-score (95% CI 0.17, 0.46). The height-for-age of the non-stunted children also increased (0.96 Z-score; 95% CI 0.70, 1.22). Our results suggest that some catch-up growth is possible even when children remain in poor environments. Long-term benefits of supplementation to growth may not be achieved when intervention begins after age 12 mo in children who have already become undernourished.