Intra-individual variability in infancy: Structure, stability, and nutritional correlates

Motor activity and intra-individual variability according to sleep-wake states in preschool-aged children with iron-deficiency anemia in infancy

BACKGROUND

A chronic or acute insult may affect the regulatory processes that guide motor and behavioral performance, leading to increased intra-individual variability (IIV). Increased variability is often interpreted as an indication of regulatory dysfunction. Iron plays an important role in the regulatory processes of the nervous system and affects motor activity. To our knowledge, no study has examined the long-lasting patterns and IIV of motor activity following iron-deficiency anemia in human infants.

AIMS

This study compared 48-h motor activity and variability in preschool-aged children with or without iron-deficiency anemia (IDA) in infancy.

METHODS

Motor activity was recorded through actigraphs during two week-days in 47 4-year-old Chilean children (23 former IDA and 24 non-anemic in infancy). All were given oral iron as infants. Sleep-wake states were identified by means of automated software. The frequency of movement units per minute was determined for each waking/sleep state during the individual day and night periods; data were examined in blocks of 15 min. Analyses of mean frequency and duration and intra-individual variability were conducted using multivariate mixed models.

RESULTS

For daytime sleep, former IDA children were more active without a difference in the total duration. They also spent less time awake throughout the individual day period. Motor activity intra-individual variability was higher in former IDA children.

CONCLUSIONS

The findings suggest that IDA in infancy sets the stage for long lasting dysfunction in the neural processes regulating sleep-wake states and spontaneous motor activity patterns.

Infant responsiveness, alertness, haemoglobin and growth in rural Sidama, Ethiopia

Several recent studies have supported relations between infant behaviour (alertness and responsiveness) and nutrition in addition to investigating infant behaviour within the context of changes in iron status over time. Existing research is typically limited to the investigation of the effects of a single vitamin or mineral, and no studies have been found that examined the influence that early alertness and responsiveness have on growth in early infancy, despite the fact that relations between behaviour and nutritional status may be bidirectional. The current study used a sample of Ethiopian infants and investigated anthropometrics, haemoglobin, the frequency of alertness and the frequency of responsiveness at 6 and 9 months of age. Six-month weight-for-age predicted 9-month frequency of alertness, while 6-month haemoglobin predicted 9-month frequency of responsiveness. Compared with responsive infants, non-responsive infants at 6 months remained more non-responsive at 9 months, although weight-for-age for both groups converged at 9 months. Results support relations between nutrition and behaviour (alertness and responsiveness) and provide evidence of a potentially useful tool (the Laboratory Temperament Assessment Battery) that was adapted to evaluate these relations in Ethiopia.

Annual Research Review: Improved nutrition--pathway to resilience

BACKGROUND

Early child nutritional deficiencies are prevalent in low- and middle-countries with consequences linked not only to poor survival and growth, but also to poor development outcomes. Children in disadvantaged communities face multiple risks for nutritional deficiencies, yet some children may be less susceptible or may recover more quickly from malnutrition. A greater understanding is needed about factors which moderate the effects of nutrition-related risks and foster resilience to protect against or ameliorate poor development outcomes.

METHODS

A literature review was undertaken from August to December 2011 and updated in August 2012. Key word searches using terms Nutrition, Malnutrition, Child Development, Responsive Care, Stimulation, Low and Middle Income Countries and Resilience were undertaken using PubMed and Psychinfo.

RESULTS

Dietary adequacy is critical for growth and development, but current evidence indicates that nutrition supplementation alone is insufficient to foster resilience to protect against, mitigate, and recover from nutritional threats and to promote healthy development. The combination of nutrition interventions with stimulation and responsive care is necessary. Combined nutrition and psychosocial stimulation approaches can potentially work effectively together to promote protective factors and mitigate risks for poor cognitive, motor, social, and affective functioning helping children to adapt in times of adversity. However, there are gaps in our existing knowledge to combine nutrition and psychosocial stimulation interventions effectively and promote these interventions at scale.

CONCLUSIONS

Research needs to address barriers at the level of family, community, programme, and policy which have prevented thus far the uptake of combined nutrition and psychosocial intervention strategies. Further investigations are needed on how to provide support to caregivers, enabling them to implement appropriate care for feeding and stimulation. Finally, the effect of combined interventions on pathways of care and protective mediators that foster resilience need to be better understood to determine focus areas for content of combined intervention curricula which help families in high-risk settings.

Inequality in early childhood: risk and protective factors for early child development

Inequality between and within populations has origins in adverse early experiences. Developmental neuroscience shows how early biological and psychosocial experiences affect brain development. We previously identified inadequate cognitive stimulation, stunting, iodine deficiency, and iron-deficiency anaemia as key risks that prevent millions of young children from attaining their developmental potential. Recent research emphasises the importance of these risks, strengthens the evidence for other risk factors including intrauterine growth restriction, malaria, lead exposure, HIV infection, maternal depression, institutionalisation, and exposure to societal violence, and identifies protective factors such as breastfeeding and maternal education. Evidence on risks resulting from prenatal maternal nutrition, maternal stress, and families affected with HIV is emerging. Interventions are urgently needed to reduce children's risk exposure and to promote development in affected children. Our goal is to provide information to help the setting of priorities for early child development programmes and policies to benefit the world's poorest children and reduce persistent inequalities.

Iron, Lead, and Children's Behavior and Cognition

Iron deficiency (ID) is the most common micronutrient deficiency in the world, with consequences of ID and ID anemia (IDA) in young children including behavioral and cognitive deficits. In turn, lead exposure is one of the most common environmental toxicants affecting children. Elevated blood lead levels (BLLs) in young children are also associated with behavioral and cognitive deficits. The metabolic and physiological connections between iron and lead, including a common route of entry into the body and similar neural targets, suggest a considerable overlap in their effects on functional outcomes. Very few studies have examined the existence of increased susceptibility to lead neurotoxicity in children with ID, but there is evidence that ID and BLL are independently associated with cognition and behavior. Children's susceptibility to both ID and elevated BLLs will likely depend on the timing and severity of both exposures, something that should be investigated systematically.

Iron deficiency anemia and affective response in rhesus monkey infants

Infant iron deficiency anemia (IDA) occurs spontaneously in monkey populations as it does in humans, providing a model for understanding effects on brain and behavior. A set of 34 monkey infants identified as IDA (hemoglobin <11 g/dl) over a 5-year period at the California National Primate Research Center (CNPRC) was compared to a set of 57 controls (hemoglobin >12 g/dl) matched for age and caging location. The infants had participated in a Biobehavioral Assessment conducted at 3-4 months of age at CNPRC that included measures of behavioral and adrenocortical response to a novel environment. IDA males differed from control males in two factors ("activity," "emotionality") derived from observational data taken on the first and second day of the exposure to the novel environment. In the male infants, IDA was associated with less restriction of activity in the novel environment on both days and less emotionality on the second day (p < .05). IDA males also displayed less response to approach by a human (human intruder test) than did control males. IDA females did not differ from controls. Adrenocortical response was not significantly affected. These findings may be relevant to functional deficits in human infants with IDA that influence later behavior.