Maternal supplementation and bone growth in infancy

History and Design of the INCAP Longitudinal Study (1969-1977) and Its Impact in Early Childhood

The Institute of Nutrition of Central America and Panama (INCAP) longitudinal study of 1969 to 1977 was a community randomized trial in which 2 pairs of matched villages received either a protein-rich gruel (atole) or a nonprotein, low-energy drink (fresco). Both contained equal amounts of micronutrients by volume. I review the history and design of the study and impact on dietary intakes and physical growth. The design dates from the 1960s when protein was seen as the main dietary deficiency. During the 1970s, emphasis shifted to energy deficiency and this influenced early analyses. Energy from the 2 drinks during pregnancy was associated with improved birthweights and whether protein was also provided along with energy appeared to make no difference. These analyses, observational in nature, were possible because there was substantial overlap in energy intakes from the supplements during pregnancy across village types. In children, analyses initially focused on energy but eventually relied on the original experimental design. Exposure to the atole compared to fresco was associated with improved physical growth at 3 years of age but not from 3 to 7 years. Consumption of the fresco in the first 3 years of life was low such that there was little overlap in energy intakes from the supplements, not allowing for the type of analyses done for pregnancy. Diets in atole villages were greater from 15 to 36 months in protein, energy, and micronutrients, making attribution of impact on growth to a specific nutrient impossible. The atole improved linear growth, arm, and calf circumferences at 3 years but not skinfold thicknesses.

Physical growth and development of the malnourished child: contributions from 50 years of research at INCAP

This paper reviews the main findings and policy implications of 50 years (1949-1999) of research conducted by INCAP on growth and development. Topical areas reviewed include a) maternal size and birthweight and the causes of intrauterine growth retardation (IUGR), b) patterns and causes of postnatal growth retardation, c) the relative importance of genetics and the environment in explaining differences in growth among populations, d) the implications of being small, for both children and adults, e) bone growth and maturation and dental development, f) menarche, and g) methodological contributions such as anthropometric reference data, quality control of data collection, development of risk indicators and use of anthropometry in nutrition surveillance systems. Key contributions to knowledge by INCAP include a) characterization of growth failure and maturational delays as mainly occurring during the intrauterine period and the first 3 years of life b) clarification of the role of small maternal size and of inadequate dietary intakes during pregnancy as major causes of intrauterine growth failure, c) evidence that diarrheal diseases and poor dietary intakes are the principal causes of growth failure in early childhood, d) demonstration that environmental factors related to poverty, and not genetic or racial ancestry, account for most of the differences in growth between populations, e) evidence that growth failure predicts functional impairment in the child as well as in the adult andf) demonstration that nutrition interventions are effective in preventing growth failure and its consequences, if targeted to needy women and young children. INCAP's work has contributed knowledge that has informed and improved policies and programs aimed at overcoming maternal and child undernutrition and promoting optimal growth and development.

Maternal nutrition, intrauterine programming and consequential risks in the offspring

It is traditionally believed that genetic susceptibility and adult faulty lifestyle lead to type 2 diabetes, a chronic non-communicable disease. The "Developmental Origins of Health and Disease" (DOHaD) model proposes that the susceptibility to type 2 diabetes originates in the intrauterine life by environmental fetal programming, further exaggerated by rapid childhood growth, i.e. a biphasic nutritional insult. Both fetal under nutrition (sometimes manifested as low birth weight) and over nutrition (the baby of a diabetic mother) increase the risk of future diabetes. The common characteristic of these two types of babies is their high adiposity. An imbalance in nutrition seems to play an important role, and micronutrients seem particularly important. Normal to high maternal folate status coupled with low vitamin B(12) status predicted higher adiposity and insulin resistance in Indian babies. Thus, 1-C (methyl) metabolism seems to play a key role in fetal programming. DOHaD represents a paradigm shift in the model for prevention of the chronic non-communicable diseases.

Reliability and validity of parental measurements of infant size

This study evaluates the reliability and validity of parental measurements of infant size, using illustrated instructions and simple measuring tools. Following pilot tests, final methods were evaluated on a sample of 28 parents (26 mothers and 2 fathers) of infants from 1 to 6 weeks of age. Parents independently measured twice the infant's head circumference (HC), mid-upper arm circumference (MUAC), abdominal circumference (AC), and recumbent length (RL). Infants were also measured twice by a trained observer. Mean parental measures were correlated (intraclass R) with the observer criterion measures at the levels of 0.81 for RL, 0.70 for AC, 0.80 for MUAC, and 0.94 for HC. Relative differences in the means for measurements obtained by parents and the trained observer were small, ranging from 0.3% for HC and RL, to 3.8% for AC. Intraclass correlations of reliability between the two parental measurements ranged from R = 0.84 for MUAC to 0.96 for RL. Given the reliability and validity of the results, the methods tested yield measurements that are suitable for ranking individuals and for use in group-level analyses, and at least in the case of head circumference, for individual-level analyses.

Hypovitaminosis A: A model for sudden infant death syndrome

The cause of sudden infant death syndrome (SIDS) is unknown. It is the leading cause of death from age one month to one year in North America. The purpose of this essay is to generate some testable hypotheses as to the cause of SIDS by drawing attention to distinct epidemiological parallels between SIDS and a newly recognized form of enamel hypoplasia, termed localized hypoplasia of the primary canine tooth (LHPC), which has been attributed to vitamin A deficiency. LHPC and SIDS share a common epidemiological profile: winter seasonality, occurrence at 3-5 months, and affecting apparently healthy children, but with increased incidence in socio economically disadvantaged families particularly racial/ethnic minorities (except Hispanics who show a reduced incidence), previously compromised infant health, less prenatal counselling, and less breastfeeding. Vitamin A has pervasive functions throughout the body including bone growth and maintenance of epithelial membranes. It is proposed that SIDS is due in part to hypovitaminosis A through one of several mechanisms: imbalanced basicranial growth producing mechanical constriction on the respiratory nerves passing through the jugular foramen; or through compromised myelination and/or maturation of the brain stem and cranial nerves involved in respiration; or through pharyngeal collapse due to mandibular undergrowth; or dysfunction of hypoxia-sensitive epithelial cells in the trachea. It is recommended that assay of hypoxia-sensitive epithelial cells in the trachea. It is recommended that assay of the retinyl ester content of the liver of SIDS victims be included in autopsy protocol. © 1995 Wiley-Liss, Inc.

Response of bone and enamel formation to nutritional supplementation and morbidity among malnourished Guatemalan children

The effects of changes in nutritional and health status upon bone and enamel development are examined in a sample of 63 rural Guatemalan children (24 females, 39 males). The number of ossified hand-wrist centers at 3 years and the number of linear enamel hypoplasias (LEH) in approximately 0-3 year zones of developing teeth were used to monitor the response of bone mineralization and enamel matrix formation to illness and nutritional supplementation. Numbers of ossified centers and LEH were compared across sex, supplementation, and morbidity groups. Enamel matrix secretion responded positively to increased supplementation. Children who received less than 34.25 kcal/day in supplement had more LEH than those who received more supplement. No differences in ossification status were found between supplementation groups. These data suggest that enamel formation may be more sensitive to changes in nutritional status than is bone mineralization. Disruptions of bone and enamel formation were both associated with frequent illness. Children who were ill more than 3.6% of the time had more LEH and fewer ossified hand-wrist centers than children who were less frequently ill. Conclusions regarding relative environmental sensitivity must take into account the specific aspects of dental and skeletal development examined.