Search PubMed⌕ Search

Biomedical subjects

K F Michaelsen

Publications and source records attributed to K F Michaelsen.

At least 73 records · Page 4Linked to original sources
PubMed1998

Geophagy, iron status and anaemia among primary school children in Western Kenya.

As part of a cross-sectional study among 156 primary school children (median age 13 years, range 10-18) in Western Kenya, geophagy was assessed through interviews. 114 (73.1%) of these children reported eating soil daily. Haemoglobin levels were determined in all 156 children and serum ferritin concentrations in 135. The mean haemoglobin (Hb) concentration was 12.7 g/dl, and median ferritin concentration 27.2 microg/l. Both the proportion of anaemic (Hb < 11.0 g/dl) and of iron-depleted (ferritin < 12 microg/l) children was significantly higher among the geophageous children than among the nongeophageous (9.6% vs. 0% anaemia; P = 0.037; 18.4% vs. 5.4% iron depletion; P = 0.046). Serum ferritin and haemoglobin concentrations were not correlated (r = 0. 13 5; P = 0. 100). Multiple regression analysis showed that geophagy, hookworm eggs per gram faeces and malaria parasite counts per microl blood were independent predictors of serum ferritin, when controlling for other helminth infections, age and sex, and socio-economic and educational background of the children's families and family size (y = 36.038-11.247(geophagy) -- 0.010(hookworm epg) + 0.001(malaria parasite counts); R2 = 0.17). Multiple regression analysis with haemoglobin as dependent variable and the same independent variables did not reveal any significant predictors. Analysis of the soil eaten by the children revealed a mean HCl-extractable iron content of 168.9 mg/kg (SD 44.9). Based on the data on the amounts eaten daily and this mean iron content, soil could provide on average 4.7 mg iron to a geophageous child (interquartile range 2.1-7.1 mg), which is equivalent to 32% of the Recommended Nutrient Intake (RNI) for girls (interquartile range 14-48%) or 42% of the RNI for boys (interquartile range 19-63%). Iron depletion and anaemia are associated with geophagy, but only serum ferritin concentrations were shown to be dependent upon geophagy in the regression model. From the cross-sectional data no inference about causality can be made. To clarify the possible causal relationships involved, longitudinal studies and iron-supplementation intervention studies are needed.

Adolescent↗
PubMed1998

Influence of weight, age and puberty on bone size and bone mineral content in healthy children and adolescents.

The biology of bone mineralization during growth is important for peak bone mass. The aim of the study was to examine how body size, age and puberty influence bone size and bone mineral density. Whole body bone area (BA) and bone mineral content (BMC) were examined by dual-energy X-ray absorptiometry (Hologic 1000/W) in healthy girls (n = 201) and boys (n = 142) aged 5-19 y. The influence of height, weight, age and puberty on bone mineralization was examined by multiple regression. Main determinants of BA were height and weight. Bone width, approximated by BA corrected for height, increased highly significantly with weight and depended weakly significantly on pubertal stage. Main determinants of BMC were BA, height, age and pubertal stages. Bone mineral density, approximated by BMC corrected for BA and height, depended on age and pubertal stage, but not on weight. Thus skeletal size is mainly determined by body size, while bone density is determined by age and pubertal stage.

Absorptiometry, Photon↗
PubMed1998

Influence of breastfeeding and complementary food on growth between 5 and 10 months.

The aim of this study was to examine the nature of the association between breastfeeding, complementary feeding and growth in a random sample of infants from Denmark, where the prevalence of breastfeeding is high. A semiquantitative food frequency questionnaire and a questionnaire on breastfeeding duration and on weight and length measurements taken at the infant welfare visit at 5 and 10 months were sent to 590 families with 10-month-old infants. A total of 339 infants with complete growth data were included in the analyses. When controlling for mid-parental height and birth weight infants breastfed for > or =7 months gained 198 g less in weight (p < 0.01) and 7 mm less in length (p < 0.01) during the period from 5 to 10 months than infants breastfed for < 7 months. Controlling for these effects, the 10% of the sample with the highest protein intake (i.e. > or =16 energy percentage) gained 262 g more than those with a lower protein intake (p = 0.03). Infants breastfed for > or =7 months received significantly less cow's milk (p < 0.01), and fewer meat-containing dishes (p < 0.05) and sweets or cakes (p < 0.01), which may partly explain the effect of breastfeeding. The long-term consequences of this moderate difference in growth velocity are unknown and the findings should not be used to advocate against breastfeeding during late infancy.

Breast Feeding↗
PubMed1998

Meat intake and iron status in late infancy: an intervention study.

BACKGROUND: Highly bioavailable dietary iron is needed to ensure optimal iron status in infants during weaning. The purpose of the current study was to examine the effect of increased meat intake on hemoglobin concentration (Hb), serum ferritin (SF), and serum transferrin receptors (TfR) in late infancy. METHODS: Forty-one healthy, term, partially breast-fed 8-month-old infants were randomized into two groups: a low-meat group (LMG), in which infants received a diet with a mean meat content of 10 g/day and a high-meat group (HMG), in which infants received a diet with a mean meat content of 27 g/day. The intervention lasted for 2 months, and blood samples were drawn on the first and the last days of the intervention. RESULTS: At the beginning of the intervention, no significant differences were found in Hb, SF, TfR values between the two groups. After the intervention, there was a significant (p = 0.008) difference in the change in hemoglobin (delta Hb) concentration. In the LMG delta Hb was -4.9 g/l (range, -12.9-5.6 g/l) and in the HMG -0.6 g/l (range, -12.1-7.3 g/l). There was no significant difference in change in SF or TfR concentrations between the LMG and the HMG. The intake of iron from meat (mean; range) was significantly higher (p = 0.0001) in the HMG (0.4 mg/day; 0.02-0.7 mg/day) than in the LMG (0.1 mg/day; 0.03-0.5 mg/day). However, there was no significant difference in total iron intake between the HMG (3.1 mg/day; 0.4-6.2 mg/day) and the LMG (3.4 mg/day; 1.4-6.1 mg/day). CONCLUSION: The results suggest that an increase in meat intake can prevent a decrease in Hb in late infancy, probably by enhancing iron absorption. However, there was no effect on iron stores or on cellular iron deficiency, evaluated by SF and TfR levels, respectively.

Anthropometry↗
PubMed1998

Effect of formula supplemented with docosahexaenoic acid and gamma-linolenic acid on fatty acid status and visual acuity in term infants.

BACKGROUND: Docosahexaenoic acid is present in high concentration in retina and does not influence visual development in preterm infants. It is still under discussion whether docosahexaenoic acid is important for visual development in term infants. METHODS: Thirty-seven infants fed formula for a median of 14 days were randomized at median age of 25 days to three formulas: a) DHAGF: 0.3 wt% docosahexaenoic acid and 0.5 wt% gamma-linolenic acid; b) DHAF 0.3 wt% docosahexaenoic acid; or c) STF: standard formula without long-chain polyunsaturated fatty acids and 17 breast-fed infants were observed, using blood samples and anthropometric measurements from 1 to 4 months of age. At 4 months, visual acuity was measured by swept steady-state visual evoked potential. A cross-sectional study on 25 breast-fed infants was carried out as a reference group for the analyses. RESULTS: Infants fed the two docosahexaenoic acid-supplemented formula had relative docosahexaenoic acid concentrations in red blood cell phospholipids almost as high as those in breast-fed infants, whereas infants in the standard formula group had significantly lower levels. The addition of gamma-linolenic acid to the formula had a positive effect on red blood cell arachidonic acid levels, compared with levels obtained using fish oil only. Visual acuity was significantly different among all feeding groups (analysis of variance; p = 0.05, means +/- standard deviation: breast-fed, 0.37+/-0.06 logMAR; DHAF and DHAGF combined, 0.40+/-0.07 logMAR; and standard formula 0.44+/-0.07 logMAR. However, there was no statistical difference among the formula groups. In a multiple regression analysis including all formula-fed infants, weight at delivery (p = 0.002), but not type of formula, was significantly associated with visual acuity at 4 months of age. CONCLUSIONS: The addition of docosahexaenoic acid resulted in concentrations in red blood cells at similar levels as those in breast-fed infants, whereas the increase in visual acuity did not reach significance. The addition of gamma-linolenic acid resulted in higher arachidonic acid concentrations in red blood cells.

Anthropometry↗
PubMed1998

Bone mass after treatment for acute lymphoblastic leukemia in childhood.

PURPOSE: To study bone mass after childhood acute lymphoblastic leukemia (ALL) and determine if reduced bone mass is related to previous therapy or endocrine status at follow-up. PATIENTS AND METHODS: We studied 95 survivors of childhood ALL who were in first remission a median of 11 years (range, 3 to 23 years) after diagnosis and who had never been irradiated outside a cranial field. The bone mass was measured by dual-energy x-ray absorptiometry. The results were compared with data on 396 local controls. RESULTS: Adjusted for sex and age, the mean whole-body bone mineral content (BMC) and bone mineral areal density (BMDA) were both significantly reduced (0.4 SDs less than the predicted mean value). This was mainly caused by reduced bone mass in the 33 participants who were aged 19 years or older at follow-up. In these young adults, the mean height for age, bone area for height, and BMC for bone area were all significantly reduced. This indicated that the reduced whole-body bone mass was caused by both reduced bone size and reduced size-adjusted bone mass. Reduced bone size was related to previous cranial irradiation. Reduced size-adjusted bone mass was not significantly related to age at diagnosis or at follow-up, length of follow-up, cranial irradiation, cumulative dose of methotrexate or corticosteroids, or endocrine status at follow-up. CONCLUSION: The whole-body bone mass was reduced 11 years after diagnosis of childhood ALL. If these abnormalities remain, survivors of childhood ALL will have an increased risk for osteoporotic fractures later in life.

Absorptiometry, Photon↗
PubMed1998

The influence of meat on nonheme iron absorption in infants.

During weaning the infant has a high iron requirement, and highly available dietary iron is needed to ensure optimal iron status. Muscle tissue has been identified as an enhancer of nonheme iron absorption in adults, although the influence of meat on nonheme iron absorption in infants has not been previously reported. The effect of the addition of 25 g of meat (lean beef) on nonheme iron absorption from a home-prepared vegetable purée meal (80 g of vegetables) was investigated in infants in the present study. The meals did not differ in their contents of other known enhancers or inhibitors of nonheme iron absorption. Incorporation of stable isotopes of iron (57Fe and 58Fe) into red blood cells 14 d after intake was used to measure iron absorption, using a cross-over design in eight healthy infants 43-49 wk of age. Nonheme iron absorption was significantly increased (p = 0.002) from the vegetable purée with added meat (geometric mean 15.0%) compared with the puréed vegetables (geometric mean 9.9%). These results thus suggest that meat is also an enhancer of nonheme iron absorption in infants and that nonheme iron absorption from weaning foods can be increased by the addition of meat.

Adult↗
PubMed1998

Bone mineral density in the lumbar spine as determined by dual-energy X-ray absorptiometry. Comparison of whole-body scans and dedicated regional scans.

PURPOSE: To compare bone mineral in the lumbar spine as measured by either consecutive regional or whole-body dual-energy X-ray absorptiometry (DXA), and to develop models that predict regional results from whole-body results. MATERIAL AND METHODS: In 180 children and young adults, bone mineral in the lumbar spine was measured by a Hologic QDR-1000/W DXA scanner, using either whole-body software (which can give data for the lumbar spine subregion) or dedicated lumbar spine software. Data on 139 persons were used to compare the two methods and to develop models that predict the result of a regional scan from the result of a whole-body scan. Data on the remaining 41 persons were used to control these models. RESULTS: Bone mineral content, bone area, and bone mineral areal density (BMDA) of the lumbar spine were measured significantly lower by whole-body scans than by regional scans (p < 0.0001). The difference was larger for the lower values of bone area and BMDA. We developed models that predicted lumbar spine BMDA from whole-body results. When these models were controlled in another group, the mean error between the methods was non-significant and the error was unrelated to the BMDA value. However, the variance of the error was only minimally reduced. CONCLUSIONS: Lumbar spine bone mineral was measured significantly lower by whole-body DXA than by regional DXA. Based on local data, models were developed that removed the significant difference between the methods.

Absorptiometry, Photon↗
PubMed1998

Bone mass and body composition after cessation of therapy for childhood cancer.

Our aim was to review current information on body composition and bone mass after cessation of therapy for childhood cancer and to present preliminary data on body composition and bone mass in a group of Danish survivors of childhood leukaemia or lymphoma. Elevated body-mass index (weight/height2; BMI) is frequent after treatment for childhood acute lymphoblastic leukaemia. BMI increases during therapy or within the first year after therapy and remains abnormal thereafter. Treatment with corticosteroids, abnormal growth-hormone secretion after treatment with cranial irradiation (CI) or corticosteroids, younger age at diagnosis, or female gender were risk factors for elevated BMI in earlier studies. We evaluated 185 survivors of childhood leukaemia or lymphoma by dual-energy X-ray absorptiometry scanning. We found elevated whole-body relative fat mass, which was associated with CI. Other studies found reduced bone mass in the radius, the lumbar spine and the whole body after treatment for childhood cancer. Growth-hormone deficiency that is not adequately corrected, CI, reduced height or reduced weight were risk factors for reduced bone mass. In our 185 participants, the whole-body bone mass was also reduced significantly compared with reference values. CI and older age at follow-up were risk factors for reduced bone mass. We conclude that the elevated relative fat mass and reduced bone mass seen after treatment for childhood leukaemia or lymphoma is associated mainly with CI.

Adolescent↗
PubMed1997

Randomised trial of effect of vitamin A supplementation on antibody response to measles vaccine in Guinea-Bissau, west Africa.

BACKGROUND: WHO has recommended vitamin A supplementation for children aged 6 months or older in developing countries at the same time as immunisation. One study has reported significantly lower seroconversion ratios among children who have received vitamin A supplements with measles vaccine at age 6 months. The aim of our study was to assess the effect of vitamin A supplementation on antibody response to measles vaccination at age 9 months, which is the more common age for immunisation in developing countries. METHODS: In an urban community in Guinea-Bissau, we did a randomised, double-blind, placebo-controlled study of the effect of simultaneous vaccination and vitamin A supplementation in 462 children who received either a two-dose schedule of measles vaccine at the ages of 6 months and 9 months (150 infants) or one dose of measles vaccine at age 9 months (312 infants). Children were followed up to the age of 18 months and a blood sample was then collected to assess the antibody response. FINDINGS: 397 (86%) of the children took part in the follow-up (52 [11%] had moved and 13 [3%] had died). Among children who received a two-dose vaccine schedule, seroconversion was 98%. There was no difference in seroconversion or geometric mean titre (GMT) for children receiving vitamin A compared with children receiving no supplement. Among children receiving only one dose of measles vaccine at age 9 months, seroconversion was 95%. The GMT was significantly higher in children receiving vitamin A than in those receiving no supplement (3704 vs 2439 mIU; GMT ratio 1.52 [1.22-1.88]). The effect on plasma antibody concentration in the blood was stronger for boys (3902 vs 1916 mIU; GMT ratio 2.04 [1.53-2.72]) than for girls (3502 vs 3017 mIU; GMT ratio 1.16 [0.85-1.58]) who had received vitamin A with measles vaccine. In a multivariate analysis of variance adjusted for sex, vitamin A supplementation was associated with higher antibody titres (p < 0.001). There was a significant interaction between vitamin A supplementation and sex (p = 0.02). INTERPRETATION: There is no indication that simultaneous administration of measles vaccine and vitamin A supplements has a negative effect on measles immunity. Among the children who had received two doses of measles vaccine at the ages of 6 months and 9 months, supplements of vitamin A had no significant effect. Among children only receiving one dose of measles vaccine at age 9 months, 100,000 IU vitamin A increased antibody concentrations, especially for boys.

Antibodies, Viral↗
PubMed1997

The impact of zinc supplementation on growth and body composition: a randomized, controlled trial among rural Zimbabwean schoolchildren.

OBJECTIVES: To assess the effect of zinc supplementation on growth and body composition among schoolchildren. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING AND SUBJECTS: 313 rural Zimbabwean schoolchildren (144 boys and 169 girls, 11-17 y). INTERVENTIONS: Supplementation with zinc (30 or 50 mg) or placebo on schooldays for 12 months. Due to drought, a food programme was in operation during the last eight months of the study. VARIABLES: Weight, height, upper arm circumference, triceps skinfold thickness, and weight-for-age, height-for-age, weight-for-height, arm muscle-area-for-age and arm fat-area-for-age Z-scores. RESULTS: Significant effects on weight gain (0.51 vs 0.14 kg, P = 0.01), weight-for-age Z (-0.08 vs -0.14, P = 0.01) and arm muscle area-for-age Z-score (0.10 vs 0.01, P = 0.03) were seen over the first three months, whereas no effects were seen over the full 12 months. CONCLUSIONS: Zinc deficiency impairing lean body mass and weight gain was documented. However, the effect of zinc seen over the first three months vanished during the last nine months when the food programme was in operation. Zinc deficiency may have persisted, but another nutrient may have become growth limiting during the last nine months.

Adolescent↗
PubMed1997

The impact of zinc supplementation on Schistosoma mansoni reinfection rate and intensities: a randomized, controlled trial among rural Zimbabwean schoolchildren.

OBJECTIVES: To assess the effect of zinc supplementation on susceptibility to S. mansoni reinfections among schoolchildren. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING AND SUBJECTS: 313 rural Zimbabwean schoolchildren (144 boys and 169 girls), 11-17 y). INTERVENTIONS: Supplementation with zinc (30 or 50 mg) or placebo on schooldays for 12 months. Due to drought, a food programme was in operation during the last eight months of the study. OUTCOME MEASURES: S. mansoni and S. haematobium reinfection rates and intensities. RESULTS: There was no difference in reinfection rates between the zinc and placebo groups (25 vs 29%, P = 0.46). However, the median intensity of S. mansoni reinfection, although low in both groups, was significantly lower in the zinc than in the placebo group (7 vs 13 eggs per gram of faeces, P = 0.048). No difference in either S. haematobium reinfection rates or intensities were seen. CONCLUSIONS: Zinc supplementation reduced the intensity of S. mansoni reinfections. Although the intensities of reinfection were very low, the finding probably reflects a biological effect of zinc that could be of public health importance in settings with higher transmission.

Adolescent↗
PubMed1997

Serum retinol concentrations and Schistosoma mansoni, intestinal helminths, and malarial parasitemia: a cross-sectional study in Kenyan preschool and primary school children.

Parasitic determinants of serum retinol concentrations were studied in 159 preschool (0.25-5.1 y) and 695 primary school (9.2-17 y) children in western Kenya. Mean serum retinol was 0.63 micromol/L in preschool and 0.94 micromol/L in primary school children; 62% and 24%, respectively, had serum retinol < 0.70 micromol/L. Serum retinol was lower in boys than in girls among both preschool (P = 0.04) and primary school children (P = 0.0001). Schistosoma mansoni, Ascaris lumbricoides, hookworm, and Trichuris trichiura egg output and malarial parasitemia were determined and their relation with serum retinol assessed. Among preschool children, sex, elevated serum concentrations of C-reactive protein, and malarial parasitemia were significant predictors of serum retinol. Among the 63 children from whom stool samples were available, none of the helminth infections were significant predictors of serum retinol. For primary school children, age, sex, and S. mansoni egg output were predictors of serum retinol. Malarial parasitemia among nonimmune preschool children may contribute to low serum retinol, whereas malarial parasitemia did not have any effects in semiimmune primary school children. In contrast, the inverse relation between S. mansoni and serum retinol found in primary school children could be due to an effect of infection on serum retinol or an increased susceptibility to infection among children with low serum retinol. Although parasitic infections may contribute to poor vitamin A status in children, they do not explain the age and sex differences.

Adolescent↗
PubMed1997

Whole body bone mineral content in healthy children and adolescents.

Data from healthy children are needed to evaluate bone mineralisation during childhood. Whole body bone mineral content (BMC) and bone area were examined by dual energy x ray absorptiometry (Hologic 1000/W) in healthy girls (n = 201) and boys (n = 142) aged 5-19 years. Centile curves for bone area for age, BMC for age, bone area for height, and BMC for bone area were constructed using the LMS method. Bone mineral density calculated as BMC/bone area is not useful in children as it is significantly influenced by bone size. Instead, it is proposed that bone mineralisation is assessed in three steps: height for age, bone area for height, and BMC for bone area. These three steps correspond to three different causes of reduced bone mass: short bones, narrow bones, and light bones.

Adolescent↗
PubMed1997

Free insulin-like growth factor I serum levels in 1430 healthy children and adults, and its diagnostic value in patients suspected of growth hormone deficiency.

Serum levels of total insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) reflect endogenous GH secretion in healthy children, which makes them good diagnostic markers for screening of GH deficiency (GHD) in short children, although some controversy still exists. Only a minor fraction of the total IGF-I circulates in its free form, which is believed to be the biologically active form. However, our knowledge of the clinical or physiological value of determination of free IGF-I in serum is limited at present. In adults, the diagnostic value of total IGF-I and IGFBP-3 determinations in patients suspected of GHD has only been reported in a few studies, whereas no previous reports on the diagnostic value of free IGF-I levels in adults suspected of GHD exist. Serum levels of free IGF-I were determined in 1430 healthy children, adolescents, and adults by a newly developed, commercially available immunoradiometric assay (Diagnostic Systems Laboratories) to establish valid normative data for this analysis. We studied the diagnostic value of free IGF-I in relation to total IGF-I and IGFBP-3 determinations in adults who were suspected of GHD. A GH provocative test, using oral clonidine, was performed in 108 adult patients who had previously been treated with GH in childhood. In healthy subjects, free IGF-I levels increased during childhood, with the highest mean values during puberty. After puberty, a subsequent decline in serum levels of free IGF-I was apparent. We found, unmeasurable free IGF-I values in 34 of the prepubertal children (3.3%). All individuals over 8 yr of age had measurable free IGF-I levels that amounted to approximately 1% of the total IGF-I concentrations. Free IGF-I levels were below--2 SD in 56 of 79 GHD patients (sensitivity, 71%) and above--2 SD in 24 of 29 patients with a normal GH response (specificity, 83%). Multiple linear regression analysis demonstrated that free IGF-I was significantly dependent on peak GH levels, duration of the disease, and number of other pituitary axes affected. We conclude that free IGF-I serum levels increase during childhood with a peak in puberty, whereafter free IGF-I levels return to prepubertal levels. Three percent of healthy prepubertal children had unmeasurable free IGF-I levels using this assay. We found that determination of the free IGF-I serum concentration may predict the outcome of a GH provocative test in adults suspected of GHD, but that a single determination of free IGF-I offered no significant advantage compared to determination of total IGF-I or IGFBP-3 serum levels.

Adolescent↗