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Biomedical subjects

K F Michaelsen

Publications and source records attributed to K F Michaelsen.

At least 91 records · Page 5Linked to original sources
PubMed1996

Visual acuity and erythrocyte docosahexaenoic acid status in breast-fed and formula-fed term infants during the first four months of life.

It has been recognized that preterm infants have a more rapid development of visual acuity if fed human milk or a formula enriched with the long-chain polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA) compared to a standard formula devoid of LCPUFA. Few studies have addressed whether the same is also true in term infants. The aim of the present study was to follow visual acuity and fatty acid composition in red blood cells (RBC) for the first 4 mon of life in 17 breast-fed and 16 formula-fed term infants. The formula used did not contain LCPUFA, but contained 1.7 wt% alpha-linolenic acid, and the linoleic/alpha-linolenic acid ratio was 8.5. The increase in visual acuity measured by Teller acuity cards developed more rapidly in breast-fed infants compared to formula-fed infants (P < 0.001). This was parallelled by a decrease in DHA of RBC in formula-fed infants, and with a significantly lower level at two and four months as compared to breast-fed infants. The content of DHA in milk from the breast-feeding mothers was high compared to other Western countries. The difference in visual acuity between the two feeding groups could be due to differences in DHA status as reflected by the RBC levels, but other explanations are possible. Intervention studies are required to verify if development of visual acuity in term formula-fed infants is dependent on the DHA level of formula.

Breast Feeding↗
PubMed1996

Decreased thymus size in formula-fed infants compared with breastfed infants.

The objective of this research was to investigate if breastfeeding affects the size of the thymus. Ultrasound assessment of the thymic index (a volume estimate) at birth and age 4 months in 47 healthy infants born in the hospital were used. History of feeding mode, body size and illness were registered. At 4 months the geometric mean thymic index (range) was 38.3 (16.2-83.2) in exclusively breastfed infants (n = 21), 27.3 (15.6-50.0) in partially breastfed infants (n = 13) and 18.3 (12.2-32.6) in formula fed infants (n = 13; p = 0.0001, ANOVA). This finding was independent of weight, length, sex and previous or current illness. There was no significant difference in mean thymic index at birth between the three feeding groups and mean thymic index had increased in all three groups from birth to 4 months. For the formula-fed infants it seems that the thymus remains large for a period and then decreases in size after breastfeeding has been terminated. We conclude that the thymus is considerably larger in breastfed than in formula-fed infants at the age of 4 months. The cause of this difference is unknown but human milk contains many immune modulating factors that might cause this effect.

Analysis of Variance↗
PubMed1996

Serum concentration of micronutrients in relation to schistosomiasis and indicators of infection: a cross-sectional study among rural Zimbabwean schoolchildren.

OBJECTIVE: To study the relation between indicators of infection and Schistosoma mansoni and S. haematobium infection, and serum concentrations of zinc, ferritin and retinol. DESIGN: Cross-sectional. SETTING AND SUBJECTS: 313 rural Zimbabwean schoolchildren (144 boys and 169 girls, 11-17 years). VARIABLES: S. mansoni and S. haematobium egg output, concentration of C-reactive protein, neutrophil count, questionnaire data on fever and diarrhoea, and serum concentrations of retinol, ferritin and zinc. RESULTS: Age, elevated CRP, fever and S. mansoni egg output were significant predictors of the concentration of retinol. The regression coefficient for age was positive, and negative for elevated CRP, fever and S. mansoni egg output. As S. mansoni, but not S. haematobium, was of significance, it is unlikely that low retinol level increased susceptibility to infection. The effect of S. mansoni on retinol level was 0.03 mumol/l (95% CI: 0.002-0.06, P = 0.03) for each 100 eggs/g increase in egg output. Neither indicators of infection nor age and sex were predictors of concentration of zinc and log10 concentration of ferritin. CONCLUSION: S. mansoni infection reduced retinol level, when indicators of infection and age were controlled for. High intensities of S. mansoni infection may induce vitamin A deficiency among children with marginal vitamin A status. The study emphasizes the importance of controlling for age and metabolic response to concurrent infections in studies using serum retinol as a measure of vitamin A status.

Adolescent↗
PubMed1995

[Duration of breast feeding--which factors are significant?].

Duration of breast-feeding (BF) was studied in 249 randomly chosen healthy, term infants of Danish origin of which 81% participated. BF was initiated by 99.5% of the mothers. At three, six, and nine months, 71%, 52%, and 33%, respectively, were still BF. Only one infant (0.5%) was exclusively BF beyond the age of seven months. In a Cox multiple regression analysis of factors influencing duration of BF, we found a positive association with maternal education (p < 0.001), and age (p = 0.02), and a negative association with the amount of formula given at the maternity ward (p < 0.001). Six months after delivery 79% of the mothers with higher school education (> or = 12 years) were still BF, compared to 29% with a low school education (< or = 9 years). There is still a need for an increased effort to support mothers in BF to be focused on younger mothers with short school education. Formula supplements during the first days of life, given to 73% of the infants, were associated with shorter duration of BF and should be discouraged.

Breast Feeding↗
PubMed1995

[Importance of n-3 and n-6 fatty acids for visual function and development in newborn infants].

Long-chain polyunsaturated n-3 and n-6 fatty acids are present in human milk, but not in the majority of infant formulas sold in Denmark. The content of the n-3 fatty acid DHA is high in retinal tissue and cerebral cortex. A number of studies have suggested that the content of DHA has a positive influence on the function of cell membranes. Preterm infants receiving human milk or infant formula with DHA have a better visual acuity than those receiving infant formula without DHA. In term infants receiving infant formula the content of DHA in plasma, red blood cell membranes and cerebral tissue is reduced compared to breast-fed infants.

Child Development↗
PubMed1995

Ocular findings in cystic fibrosis patients receiving vitamin A supplementation.

BACKGROUND: Vitamin A deficiency with eye symptoms has been reported in patients with cystic fibrosis who received the recommended daily intake of vitamin A. METHODS: We measured serum retinol, dark adaptation, contrast sensitivity, and dry eye status in 35 adult cystic fibrosis patients to ascertain whether they had ocular signs or symptoms. RESULTS: Median serum retinol concentration was 1.95 mumol/l, range 1.08-4.01 mumol/l, with no values indicating vitamin A deficiency. Retinal light sensitivity was normal. Nineteen patients had reduced contrast sensitivity. Conjunctival imprints all showed plenty of goblet cells, but were characteristic of dry eye in 42% of patients (n = 14). Decreased tear film stability was found in 49% (n = 17), tear production was low in 31% (n = 11), and 23% (n = 8) showed an increased amount of dying epithelial cells. Nine patients (26%) had keratoconjunctivitis sicca according to the Copenhagen criteria. CONCLUSION: Our patients had no biochemical or clinical signs of vitamin A deficiency. We speculate that the high incidence of dry eye could be a primary manifestation of cystic fibrosis.

Adolescent↗
PubMed1995

A longitudinal study of iron status in healthy Danish infants: effects of early iron status, growth velocity and dietary factors.

In a cohort of term infants (n=91), followed from birth to 12 months, iron intake was examined by 24-h food records, and iron status by blood samples (haemoglobin (Hb)), mean corpuscular volume (MCV), serum values for iron, ferritin and transferrin, and erythrocyte protoporphyrin) at 2, 6 and 9 months. At 9 months of age, 5% had anaemia (Hb<105 g/l), but none had developed iron deficiency according to strict definitions used in this study (serum ferritin < 13 micrograms/l and transferrin saturation < 10%). Infants with high serum ferritin, serum transferrin and erythrocyte protoporphyrin values at one blood sampling also had high values at the following sample (tracking, r=0.45-0.80), suggesting that iron stores at delivery are an important determinant of iron stores during late infancy. Factors related to changes in serum ferritin were investigated by multiple linear regression. From 2 to 6 months, serum ferritin was negatively associated with knee-heel growth velocity (p=0.006) and positively with intake of infant formula (p=0.04). From 6 to 9 months it was negatively associated with intake of bread (p=0.001), and there was a trend for a positive association with intake of meat (p=0.07) and fish (p=0.08) and for a negative association with intake of cow's milk (p=0.07). In conclusion, those with a high growth velocity and a dietary pattern with a high intake of bread and a low intake of meat and fish had lower ferritin values and thereby an increased risk of depleting their iron stores later during infancy.

Anemia, Iron-Deficiency↗
PubMed1995

Serum levels of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) in healthy infants, children, and adolescents: the relation to IGF-I, IGF-II, IGFBP-1, IGFBP-2, age, sex, body mass index, and pubertal maturation.

Circulating IGF-I and -II are bound to specific insulin-like growth factor (IGF)-binding proteins (IGFBPs), of which IGFBP-3 binds the majority of the IGFs. IGFBP-3 levels are regulated by GH and have been suggested to provide additional information on GH secretory capacity compared to IGF-I. However, the diagnostic value of IGFBP-3 is still controversial, perhaps because the quality of the available normative data for IGFBP-3 varies. It has recently been shown that a large number of individuals is required to establish reference ranges for IGF-I that take into account age, sex, body mass index (BMI), and pubertal stage. Therefore, we measured IGFBP-3, IGF-I, IGF-II, IGFBP-1, and IGFBP-2 levels by RIA in 907 healthy children to establish well characterized normative data on IGFBP-3 according to age, sex, and pubertal stage and to study the complex relationship between IGFs and their BPs in puberty. We found that IGFBP-3 levels increase with age in children, with maximal levels in puberty; girls experience peak values approximately 1 yr earlier than boys. Age, sex, height, BMI, and pubertal maturation were all important factors in determining the circulating levels of IGFBP-3, whereas IGF-I levels were unaffected by BMI. Comparison of IGFBP-3 with IGF-1 concentrations revealed that they did not exhibit the same developmental pattern in puberty. IGF-I levels increased to relatively higher levels than IGFBP-3, leading to an increasing molar ratio between IGF-I and IGFBP-3 in puberty, when growth velocity is high. Concomitantly, IGF-II and IGFBP-2 levels were unchanged throughout puberty, whereas IGFBP-1 levels declined with age in prepubertal children, with lowest values in puberty. There was a highly significant correlation between IGF-I and -II and IGFBP-3 on a molar basis (r = 0.84; P < 0.0001). Thus, we speculate that IGFBP-3 is pivotal for circulating IGF bioactivity and that the increase in the molar ratio between IGF-I and IGFBP-3 reflects an increase in free, biologically active IGF-I. In conclusion, we have provided normative data on a large group of healthy individuals and conclude that age, sex, height, BMI, and pubertal maturation have to be taken into account before a single IGFBP-3 value in a growth-retarded child can be evaluated properly.

Adolescent↗
PubMed1995

Growth of breast-fed infants deviates from current reference data: a pooled analysis of US, Canadian, and European data sets. World Health Organization Working Group on Infant Growth.

OBJECTIVE: To compare growth patterns of a large sample of breast-fed infants with the current World Health Organization (WHO)/Centers for Disease Control and Prevention (CDC) reference data. METHODS: Data from seven longitudinal studies of infant growth in North America and northern Europe were pooled (n = 453 breast-fed infants). Weight, length and head circumference were compared with the WHO/CDC reference, and repeated-measures analysis of variance was used to examine associations between growth patterns and breast-feeding duration, age of introduction of solid foods, and use of other milks. RESULTS: In comparison with WHO/CDC reference data, infants breast-fed for at least 12 months (n = 226) grew more rapidly in the first 2 months and less rapidly (particularly in weight) from 3 to 12 months; the mean z score at 12 months was -0.53 for weight for age, -0.29 for length for age, and -0.32 for weight for length. In contrast, mean head circumference was well above the WHO/CDC median throughout the first year of life. These patterns were generally consistent across studies. In the full sample (n = 453), a longer duration of breast-feeding was associated with a greater decline in weight for age and weight for length but not length for age. CONCLUSION: These results suggest that if growth charts are to reflect patterns consistent with those of infants following WHO feeding recommendations, new reference data based on breast-fed infants are needed.

Age Factors↗
PubMed1994

[The importance of nutrition for the prevention of osteoporosis].

The prevalence of osteoporosis is increasing, and is a significant burden on society. Dietary composition is an important determinant of the bone mineral density in the growth period, and of the magnitude of the age related bone mineral loss, in particular among postmenopausal women. Therefore, an improvement of the diet has an important role in the prevention of osteoporosis. A sufficient intake of calcium and vitamin D can reduce the risk of fractures in postmenopausal women, and it is likely that a low calcium intake may affect peak bone mass negatively. Calcium in the Danish diet comes mainly from dairy products. Half a litre of milk and 25 g of cheese will cover most people's calcium requirement. Part of the calcium requirement may also be covered by consuming other foods such as cabbage, broccoli and beans. Children, adolescents and elderly individuals who avoid dairy products are recommended to take a calcium supplement. The status of vitamin D among the elderly can be improved by a daily outdoor stay and by a frequent intake of fatty fish such as herrings. Elderly persons who stay indoors are recommended to take a vitamin D supplement.

Adolescent↗
PubMed1994

[Children's requirements for dietary calcium].

Childrens' need for calcium is uncertain, and as a consequence there are large differences in the official recommendations for calcium intake. A low calcium intake is not followed by acute complications. A very low calcium intake (less than 200 mg/d) combined with a high intake of fibre and phytate can cause osteomalacia, as in rickets. Several studies support that calcium intake during growth is positively associated to bone mineralisation, and to peak bone mass, which is associated to the risk of developing osteoporosis. At present, we know very little about childrens' ability to adapt to a low calcium intake. Furthermore, knowledge of the capacity for catch-up mineralisation after a period of low calcium intake is limited. Bone mineralisation during growth is also influenced by physical activity, hormonal status and race. The relative importance of these factors is unknown. Longitudinal studies of bone mineralisation using DXA scanning will, in the future, increase our knowledge about the need for calcium during growth.

Adolescent↗
PubMed1994

The Copenhagen Cohort Study on Infant Nutrition and Growth: breast-milk intake, human milk macronutrient content, and influencing factors.

In 91 healthy term infants breast-milk intake was measured at 2, 4, and 9 mo by test weighing and human milk macronutrient content by infrared analysis every 2-4 wk. In infants exclusively breast-fed, mean milk intake was 781 and 855 mL/24 h at 2 and 4 mo, respectively, and correlated positively with the current weight of the infant and negatively with the amount of formula supplement given at the maternity ward. Median daily energy intake was considerably below current recommendations (423 and 381 kJ/kg body wt at 2 and 4 mo, respectively). Protein concentration in the milk was approximately 8% higher in primipara. Median daily protein intake was 1.3 and 1.0 g/kg body wt at 2 and 4 mo, respectively. Median fat concentration was 39.2 g/L and was positively associated with pregnancy weight gain. This supports the hypothesis that maternal fat stores laid down during pregnancy are easier to mobilize during lactation than are other fat stores and, if low, may limit milk fat when exhausted.

Birth Weight↗
PubMed1994

The Copenhagen cohort study on infant nutrition and growth: duration of breast feeding and influencing factors.

Duration of breast feeding was studied in 249 randomly chosen, healthy, term infants of Danish origin of which 80.7% participated. Breast feeding was initiated by 99.5% of the mothers. At 3, 6 and 9 months, 71%, 52% and 33%, respectively, were still breast feeding. Only 1 infant (0.5%) was exclusively breast fed beyond 7 months of age. In a Cox multiple regression analysis of factors influencing duration of breast feeding, we found a positive association with maternal education (p < 0.001) and age (p = 0.02) and a negative association with the amount of formula given at the maternity ward (p < 0.001). Six months after delivery, 79% of the mothers with higher school education (> or = 12 years) were still breast feeding, compared to 29% with a low school education (< or = 9 years). There is still a need for an increased effort to support mothers in breast feeding, focusing particularly on younger mothers with short school education. Formula supplements during the first days of life, given to 73% of the infants, were associated with a shorter duration of breast feeding and should be discouraged.

Adult↗