Early child health in Lahore, Pakistan: XI. Growth

Weight Velocity in Addition to Latest Weight Does Not Improve the Identification of Wasting or the Prediction of Stunting and Mortality: A Longitudinal Analysis Using Data from Malawi, South Africa, and Pakistan

BACKGROUND

In low/middle-income countries, most nutritional assessments use the latest weights, without reference to growth trajectory.

OBJECTIVES

This study explores whether velocity, in addition to the latest weight, improves the prediction of wasting, stunting, or mortality in the first 2 years of life.

METHODS

We analyzed a combined data set with weight and height data collected monthly in the first year of 3447 children from Pakistan, Malawi, and South Africa, with height and survival recorded till 24 m. The main exposures were weight-for-age z-score (WAZ) at the end of each 2-m period and weight velocity-for-age z-score (WVZ2) across that period. The outcomes were wasting, stunting, or all-cause mortality in the next 1-2 mo. As a sensitivity analysis, we also used WVZ over 6 mo (WVZ6), with matching WAZ. Cox proportional hazard models with repeated growth measures were used to study the association between exposures and mortality. Mixed Poisson models were used for stunting and wasting.

RESULTS

Children who were already stunted or wasted were most likely to remain so. Higher WVZ2 was associated with a lower risk of subsequent stunting (risk ratio [RR]: 0.95; 95% confidence interval [CI]: 0.93, 0.96), but added minimal prediction (difference in AUC = 0.004) compared with a model including only WAZ. Similarly, lower WVZ2 was associated with wasting (RR: 0.74; 95% CI 0.72, 0.76) but the prediction was only marginally greater than for WAZ (difference in AUC = 0.015). Compared with WAZ, WVZ6 was less predictive for both wasting and stunting. Low WVZ6 (but not WVZ2) was associated with increased mortality (hazard ratios: 0.75, 95% CI: 0.67, 0.85), but added only marginal prediction to a model including WAZ alone (difference in C = 0.015).

CONCLUSIONS

The key anthropometric determinant of impending wasting, stunting, and mortality appears to be how far below the normal range the child's weight is, rather than how they reached that position.

Wasting and Stunting in Infants and Young Children as Risk Factors for Subsequent Stunting or Mortality: Longitudinal Analysis of Data from Malawi, South Africa, and Pakistan

BACKGROUND

Few studies have had sufficient longitudinal data to track how different malnourished states relate to mortality at different ages and interrelate over time.

OBJECTIVES

This study aims to describe the RRs and proportions of mortality associated with wasting and stunting and the pathways into and out of these nutritional states.

METHODS

Longitudinal growth data sets collected for children ages 0-24 months from Malawi, South Africa, and Pakistan were combined (n = 5088). Children were classified as deceased, wasted (weight for height < -2 SD; 1-4%), stunted (length < -2SD; 20-47%), or wasted and stunted (WaSt; 2-5%) at ages 3, 6, 9, 12, 18, and 24 months. Mixed-effects Cox models were used to study the association between nutritional status and mortality.

RESULTS

By age 3 months, 20% of children were already stunted, rising to 49% by 24 months, while wasting (4.2% and 2.2% at 3 months, respectively) and WaSt (0.9% and 3.7% at 24 months, respectively) were less common. The HR for mortality in WaSt was 9.5 (95% CI, 5.9-15), but 60% of WaSt-associated mortality occurred at 3-6 months. Wasting or WaSt was associated with 10-23% of deaths beyond 6 months, but in the second year over half of deaths occurred in stunted, nonwasted children. Stunting persisted in 82% of children and wasting persisted in 44%. Wasted children were more likely than nonwasted, nonstunted children to become stunted (RR, 1.93; 95% CI, 1.7-2.2), but 94% of children who progressed to stunting had not been wasted in the prior period.

CONCLUSIONS

WaSt greatly increased the risk of death, particularly in very young infants, but more deaths overall were associated with stunting. Most stunting appeared to be either intrauterine in origin or arose in children without prior wasting. Either stunting and wasting represent alternative responses to restricted nutrition, or stunting also has other, nonnutritional causes.

Stunting at birth: recognition of early-life linear growth failure in the western highlands of Guatemala

OBJECTIVE

Measurements of length at birth, or in the neonatal period, are challenging to obtain and often discounted for lack of validity. Hence, classical 'under-5' stunting rates have been derived from surveys on children from 6 to 59 months of age. Guatemala has a high prevalence of stunting (49.8%), but the age of onset of growth failure is not clearly defined. The objective of the study was to assess length-for-age within the first 1.5 months of life among Guatemalan infants.

DESIGN

As part of a cross-sectional observational study, supine length was measured in young infants. Mothers' height was measured. Length-for-age Z-scores (HAZ) were generated and stunting was defined as HAZ <-2 using WHO growth standards.

SETTING

Eight rural, indigenous Mam-Mayan villages (n 200, 100% of Mayan indigenous origin) and an urban clinic of Quetzaltenango (n 106, 27% of Mayan indigenous origin), Guatemala.

SUBJECTS

Three hundred and six newborns with a median age of 19 d.

RESULTS

The median rural HAZ was -1.56 and prevalence of stunting was 38%; the respective urban values were -1.41 and 25%. Linear regression revealed no relationship between infant age and HAZ (r = 0.101, r(2) = 0.010, P = 0.077). Maternal height explained 3% of the variability in HAZ (r = 0.171, r(2) = 0.029, P = 0.003).

CONCLUSIONS

Stunting must be carried over from in utero growth retardation in short-stature Guatemalan mothers. As linear growth failure in this setting begins in utero, its prevention must be linked to maternal care strategies during gestation, or even before. A focus on maternal nutrition and health in an intergenerational dimension is needed to reduce its prevalence.

Chronic growth faltering amongst a birth cohort of Indian children begins prior to weaning and is highly prevalent at three years of age

BACKGROUND

Poor growth of children in developing countries is a major public health problem associated with mortality, morbidity and developmental delay. We describe growth up to three years of age and investigate factors related to stunting (low height-for-age) at three years of age in a birth cohort from an urban slum.

METHODS

452 children born between March 2002 and August 2003 were followed until their third birthday in three neighbouring slums in Vellore, South India. Field workers visited homes to collect details of morbidity twice a week. Height and weight were measured monthly from one month of age in a study-run clinic. For analysis, standardised z-scores were generated using the 2006 WHO child growth standards. Risk factors for stunting at three years of age were analysed in logistic regression models. A sensitivity analysis was conducted to examine the effect of missing values.

RESULTS

At age three years, of 186 boys and 187 girls still under follow-up, 109 (66%, 95% Confidence interval 58-73%) boys and 93 (56%, 95% CI 49-64%) girls were stunted, 14 (8%, 95% CI 4-13%) boys and 12 (7%, 95% CI 3-11%) girls were wasted (low weight-for-height) and 72 (43%, 95% CI 36-51) boys and 66 (39%, 95% CI 31-47%) girls were underweight (low weight-for-age). In total 224/331 (68%) children at three years had at least one growth deficiency (were stunted and/or underweight and/or wasted); even as early as one month of age 186/377 (49%) children had at least one growth deficiency. Factors associated with stunting at three years were birth weight less than 2.5 kg (OR 3.63, 95% CI 1.36-9.70) 'beedi-making' (manual production of cigarettes for a daily wage) in the household (OR 1.74, 95% CI 1.05-2.86), maternal height less than 150 cm (OR 2.02, 95% CI 1.12-3.62), being stunted, wasted or underweight at six months of age (OR 1.75, 95% CI 1.05-2.93) and having at least one older sibling (OR 2.00, 95% CI 1.14-3.51).

CONCLUSION

A high proportion of urban slum dwelling children had poor growth throughout the first three years of life. Interventions are needed urgently during pregnancy, early breastfeeding and weaning in this population.

Seasonality of growth in Shanghai infants (n=4128) born in 11 consecutive years

OBJECTIVE

To describe the seasonal growth patterns in Shanghai infants, to explore seasonal time lag between weight gain and length gain, and to investigate the long-term effect of birth season on early postnatal growth.

DESIGN

Community-based longitudinal study.

SETTING

Shanghai, People's Republic of China.

METHOD

Children were followed up monthly from 1 to 6 months, 3 monthly from 6 to 12 months, and 6 monthly from 12 to 24 months.

SUBJECTS

A total of 6018 children born between 1 January 1980 and 31 December 1990.

MAIN OUTCOME MEASURES

Weight gain, length gain and change in body mass index (BMI) over the seasons of the year.

RESULTS

The infants tended to grow faster in height in spring and summer, and faster in weight and BMI in autumn and winter. The seasonal effect on weight gain and length gain is largely independent. The mean length value at 1 month of age was about 2.0 cm higher in infants born in May to July than in those born in November to February. At 24 months of age this difference was reduced to about 0.7 cm.

CONCLUSIONS

There is a clear and consistent seasonality in growth in Shanghai infants. The seasonality seems to act independently on weight and length. Birth month has some association with attained size, but this is reduced during the first 2 y of life.

Growth stunting in early life in relation to the onset of the childhood component of growth

AIMS

Growth stunting is prevalent in developing countries. The prevalence of stunting ranges from 10-80% or more. The critical period for growth faltering in length is between six and 18 months. The aims of this study were 1) to investigate the association between the age at onset of the childhood component and growth stunting in early life; 2) to develop a screening method for identifying any individual infant subject to stunting in early life.

MATERIALS & METHODS

This community-based longitudinal study was carried out in Lahore, Pakistan. Three studied areas and one local control group were included in the study. There were 425 subjects for whom data were available for determining the age at onset of the childhood component. The onset was defined as an abrupt increase in length velocity. It was determined individually using the infancy-childhood-puberty growth model.

RESULTS

The medians of the age at onset of childhood component were 15, 13, 10 and 9 months in the periurban, village, urban and control groups, respectively. The onset was significantly related to both length and length velocity during the critical period of stunting. Based on the distribution of individual length increment from 12 to 15 months, 2.0 and 3.0 cm were chosen as the cut-off points to identify a stunting infant. In the normal onset group, 84% of the children were identified as growing normally; in the delayed onset group, 61% were identified as stunting. Using this screening method, 97% of children have a delayed onset if their length increase is below 2 cm from 12 to 15 months; 99% of them have a normal onset if the increase is above 3 cm over the same period.

CONCLUSIONS

The age at onset of the childhood component can significantly explain the variations in both length and length velocity in early life. The stunting screening method reported here is simple. It can be used in almost any situation, such as a pediatric clinic or community-based survey.

Severe mental retardation in 2 to 24-month-old children in Lahore, Pakistan: a prospective cohort study

Severe mental retardation (developmental quotient (DQ) < 50) was investigated in 1303 children from 2 to 24 months of age, born during 1984-87 in four population groups representing different socio-economic levels in and around Lahore, Pakistan. The incidence per 1000 live births was 22 in the periurban slum, 9 in the urban slum, 7 in the village and 4 in the upper middle class group. The aetiology was prenatal in 79%, perinatal in 14% and untraceable in 7% of cases. Down's syndrome was the most common cause of severe mental retardation (36%). Impairments were studied at 2 years of age. Impairment of language was present in all, while locomotor dysfunction was seen in 89% of cases. Epilepsy and cerebral palsy were each present in 22% of cases. Mortality among these severely mentally retarded children was 36%.

Postnatal growth and mental development: evidence for a "sensitive period"

For many years it has been suspected that severely impaired somatic growth during early postnatal life can be associated with the subsequent impairment of mental abilities. This study aimed to test that hypothesis on the basis of data gathered from a prospective whole population survey of infant development in south London. A year's birth cohort of 1558 full-term singletons was monitored; 47 otherwise healthy cases with serious growth faltering in the first year were recruited. Mental and psychomotor abilities were assessed at 15 months. Potentially confounding psychosocial variables, including cognitive stimulation received at home, were measured contemporaneously. A statistical model was constructed that enabled the timing, duration and severity of growth faltering to be used as predictors of mental functioning. Up to 37% of the variance in cognitive and psychomotor outcome at 15 months can be explained by the model. The first few postnatal months appear to constitute a "sensitive period" for the relationship between growth and mental development.

Early child health in Lahore, Pakistan: XII. Milestones

Psychomotor development was assessed in 1476 infants from four different levels of urbanization in and around Lahore, Pakistan. Development was assessed monthly at birth to 24 months of age by using a set of 10 milestones selected from the Denver Developmental Screening Test and the Developmental Screening Inventory. The psychomotor development of children in the upper middle (Um) class was consistent with reference population groups in Europe and North America, hence this group was used as control. There was significant delay in the psychomotor development of infants belonging to the poorer areas compared to the Um class. There was no sex difference in the development of the milestones in any study area, except for girls in the Um class who were earlier for about one month than boys in talking. Infants in the poorer areas were, on average about 3 months, delayed in their walking and fine motor activity (building a tower of 3 cubes) in comparison with the Um class. Observed disturbance in psychomotor development at an early age may affect the abilities and achievements in later life.

Early child health in Lahore, Pakistan: II. Inbreeding

The prevalence of consanguineous marriages was studied in 940 families belonging to four different socio-economic groups in and around Lahore, Pakistan. The births occurring in these families from September 1984 to March 1987 were also investigated for birth defects. The overall prevalence of consanguineous marriages was 46%. The first cousin marriages were most common (67%), followed by the marriages between second cousins, 19%. The prevalence of consanguineous marriages was clearly associated with the socio-economic status of the study groups; 50% of the marriages was related in the periurban slum, 49% in the village, 44% in the urban slum and 31% in the upper middle class. The birth defects were also more prevalent in the poorer areas, being highest in the periurban slum (17.7%) followed by the urban slum (15.6%) and then the village (14.8%) and lowest in the upper middle class (12.3%). Although, the frequency of both consanguinity and birth defects were related with the socio-economic levels of the study groups, there was no association between inbreeding and birth defects. Perhaps, deleterious recessive genes for birth defects have been "bred out", because of continuous inbreeding over generations in this population. There was a significant predilection of major birth defects in boys without clear sex linkage. The conclusion is that the rate of consanguineous marriages was high, especially in the poorer areas, but the relationship between consanguineous marriages and birth defects was little or none. However, other child health indicators may be affected by consanguineous marriages.

Early child health in Lahore, Pakistan: XIII. Primary teeth emergence

The aim of this study was to investigate the number of emerged primary teeth at various ages from 6 to 24 months in 1347 longitudinally followed Pakistan infants sampled from four socio-economically different areas in Lahore, Pakistan; from a very poor periurban slum to a privileged upper middle class group. The emergence of the primary teeth was found to be little, or not all related to sex or to the area of living. However, in comparison with studies conducted in other continents, the Indo-Pak subcontinent population lags behind in primary teeth emergence, especially in early life. This genetic difference makes it necessary to create specific standards of primary teeth emergence for this population.

Early child health in Lahore, Pakistan: IV. Child care practices

Child care practices and hygiene measures were studied at 6 months of age in a longitudinally followed cohort of 1476 infants born between September 1984 to March 1987 in four socio-economically different areas in and around Lahore, Pakistan. Although, 76-98% of the mothers looked after their infants during health and 96-98% during a diarrhoeal illness, child care practices and hygiene measures differed significantly between the four areas. During a diarrhoeal episode, the mothers from the upper middle class took timely medical help, fed ample food and Oral Rehydration Salts (ORS) to the sick infants and provided uncontaminated food to them in clean surroundings. The mothers from the village and the periurban slum took their sick child, mostly after the second day of illness, to a doctor, but preferred home remedies. Fourteen percent of the mothers in the village and 6% in the periurban slum did not seek any medical help at all. One-third of the families, from these two areas, fed food to children 12 hours after cooking; the surroundings of the child were dirty with large numbers of flies present throughout the year, though the food was commonly kept covered with a lid. We constructed a simple measure of the surroundings of the child, rated as dirty, medium or clean; it was found to be associated to both parental illiteracy and child growth, but not with housing standard. The main conclusion is that any attempt to improve child-care practices and the hygienic environment for the child, should focus on maternal literacy and simple health messages.