Stature and age as factors in the growth of second metacarpal cortical bone in moderately malnourished children

Revisiting the radiographic assessment of osteoporosis-Osteopenia in children 0-2 years of age. A systematic review

BACKGROUND

Imaging for osteoporosis has two major aims, first, to identify the presence of low bone mass (osteopenia), and second, to quantify bone mass using semiquantitative (conventional radiography) or quantitative (densitometry) methods. In young children, densitometry is hampered by the lack of reference values, and high-quality radiographs still play a role although the evaluation of osteopenia as a marker for osteoporosis is subjective and based on personal experience. Medical experts questioned in court over child abuse, often refer to the literature and state that 20-40% loss of bone mass is warranted before osteopenia becomes evident on radiographs. In our systematic review, we aimed at identifying evidence underpinning this statement. A secondary outcome was identifying normal references for cortical thickness of the skeleton in infants born term, < 2 years of age.

METHODS

We undertook systematic searches in Medline, Embase and Svemed+, covering 1946-2020. Unpublished material was searched in Clinical trials and International Clinical Trials Registry Platform (ICTRP). Both relevant subject headings and free text words were used for the following concepts: osteoporosis or osteopenia, radiography, children up to 6 years.

RESULTS

A total 5592 publications were identified, of which none met the inclusion criteria for the primary outcome; the degree of bone loss warranted before osteopenia becomes visible radiographically. As for the secondary outcome, 21 studies were identified. None of the studies was true population based and none covered the pre-defined age range from 0-2 years. However, four studies of which three having a crossectional and one a longitudinal design, included newborns while one study included children 0-2 years.

CONCLUSIONS

Despite an extensive literature search, we did not find any studies supporting the assumption that a 20-40% bone loss is required before osteopenia becomes visible on radiographs. Reference values for cortical thickness were sparse. Further studies addressing this important topic are warranted.

Maternal supplementation and bone growth in infancy

The effects of maternal supplementation during pregnancy and lactation on bone growth of infants were investigated in 272 mother-infant pairs who participated in the Guatemalan Longitudinal Study of Nutritional Supplementation, Growth and Development. Mothers received one of two nutritional supplements according to village of residence, and bone growth was determined from dimensions of the second metacarpal measured directly from hand-wrist radiographs of 3-month-old infants. Multiple regression analyses indicated significant supplementation effects on cortical bone dimensions related to the volume of supplement intake. These findings were independent of maternal characteristics and attendance at the supplementation centres, and the infant's gender, size, gestational age and morbidity experience. The nutrient composition of the supplements and the patterns of the supplementation effects eliminate proteins, energy, calcium and phosphorus as the nutrients potentially responsible for the bone-specific response. Candidate nutrients for the observed effects are vitamin A, ascorbic acid, niacin, thiamin, iron or fluorine. Presumptive evidence suggests the effects may be due to vitamin A supplementation. These findings suggest opportunities for nutritional intervention in pregnancy and the early postpartum period to prevent osteopaenia in infancy.