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Biomedical subjects

G Samuelson

Publications and source records attributed to G Samuelson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Food habits in Swedish adolescents in relation to socioeconomic conditions.

OBJECTIVE: To describe the food habits of Swedish adolescents 14-15 y of age. To analyse the connection between food habits and socioeconomic circumstances and background factors. DESIGN: Cross-sectional survey using a Food Frequency Questionnaire including questions on meal patterns. SETTING: The city of Göteborg and the County of Alvsborg, Sweden 1996. SUBJECTS: Pupils in the 8th grade in all schools in the city of Göteborg and the County of Alvsborg were in February 1996 invited to participate. The study comprised 7605 pupils. The drop-out rate was 14.4% (n = 1280). RESULTS: The adolescents had an infrequent consumption of vegetables and fruits and they had a daily consumption of sweets. Cereals, dairy products and snacks: buns, wafers, soft drinks, ice cream and potato crisps were consumed more than once a day. Thirty percent of the girls and 20% of the boys did not eat breakfast every day. The free school lunch was eaten daily by 50% of the boys and 30% of the girls, the remainder ate some type of snack. A negative correlation was found between smoking and the frequency of vegetable consumption. Pupils from areas with high socioeconomic status more often ate breakfast and lunch and the boys more often ate dinner compared to adolescents from areas with low socioeconomic status. CONCLUSIONS: An irregular meal pattern as well as snack consumption and smoking were common, especially among girls in areas with low socioeconomic status.

Adolescent↗
PubMed1998

Total energy expenditure and physical activity as assessed by the doubly labeled water method in Swedish adolescents in whom energy intake was underestimated by 7-d diet records.

Swedish children and adolescents may be adopting a sedentary lifestyle with low energy expenditures and intakes, but no quantitative data are available. The purpose of the present study in 50 adolescents aged 15 y was to investigate whether assessment of total energy expenditure (TEE) and physical activity level (PAL) by the doubly labeled water method and indirect calorimetry and estimation of energy intake by a 7-d diet record would indicate physical inactivity. The boys' (n = 25) mean weight was 112% and the girls' (n = 25) was 109% of Swedish reference values from 1976; the mean height of both boys and girls was 102% of those reference values. Mean TEE in the boys and girls, 13.82 +/- 1.90 and 10.70 +/- 1.59 MJ/d, and mean PAL (TEE/basal metabolic rate), 1.89 +/- 0.16 and 1.79 +/- 0.22, respectively, were nonsignificantly higher than corresponding figures from other published studies. Mean energy intake as a percentage of TEE was 81.9 +/- 17.9% in the boys and 78.3 +/- 16.4% in the girls. Significant negative correlations were found both between energy intake as a percentage of TEE and percentage body fat and between energy intake as a percentage of TEE and body mass index. These results add to the evidence that 7-d diet records underestimate energy intake in adolescents, particularly those with a tendency for overweight and increased body fat. The results support indications of a trend of increasing body weight and height in Swedish adolescents, but conflict with the presumptions of low physical activity, low energy expenditure, and low energy intake. These results support the view that current recommendations for energy intake during adolescence are too low.

Adipose Tissue↗
PubMed1997

A 7-day activity diary for assessment of daily energy expenditure validated by the doubly labelled water method in adolescents.

OBJECTIVES: To validate the use of an activity diary and predicted BMR for assessment of daily total energy expenditure (TEE) and physical activity level (PAL = TEE/BMR) in adolescents. DESIGN: TEE and PAL estimated from activity diary records kept for seven days and BMR predicted from age, gender and body weight were compared with the results of doubly labelled water (DLW) measurements and indirect calorimetry performed during the same time period. SETTING: The Unit of paediatric Physiology of the Department of Clinical Physiology, University Hospital, Uppsala, Sweden. SUBJECTS: Fifty randomly selected 15 y old adolescents (25 boys and 25 girls). RESULTS: The mean difference between TEE estimated in all adolescents by the activity diary and by DLW methods was 1.2%. The limits of agreement (mean difference 2 s.d.) were -3.47 and 3.77 MD/d, equivalent to a coefficient of variation of 15%. The mean difference between PAL assessed by activity diary records and by DLW measurements was 0.001, and the limits of agreement between the two methods were 0.54. CONCLUSIONS: The results imply that the activity diary method provides a close estimate of TEE and PAL in population groups.

Activities of Daily Living↗
PubMed1997

Daily energy expenditure and physical activity assessed by an activity diary in 374 randomly selected 15-year-old adolescents.

OBJECTIVES: To assess the average daily levels of physical activity, energy expenditure and the time and energy spent a different activities in two cohorts of Swedish adolescents. DESIGN: Total energy expenditure (TEE) and physical activity level (PAL = TEE/basal metabolic rate (BMR)) were estimated in 374 randomly selected healthy adolescents living with two different regions of Sweden on the basis of a seven-day activity diary (AD) and predicted BMR. A validation of the estimates from the AD with the doubly labelled water (DLW) method in a randomly selected subsample of 50 of these subjects is presented elsewhere. SETTING: The Unit of Paediatric of the Department of Clinical Physiology, University Hospital, Uppsala and the Department of Paediatrics, Northern Alvsborg Hospital, Trollhättan, Sweden. RESULTS: No significant differences in TEE and PAL were found between the adolescents of the two regions. High levels of TEE (14.2 and 10.9 MJ/d in boys and girls, respectively) and PAL (1.95 and 1.80) were observed. There was a close association between the PAL and the adolescents and their reported time spent sitting. Those with the lowest PAL values spent 3-6 h longer each day sitting compared to those with the highest PAL values. The results also indicate that everyday activities such as walking and bicycling have a crucial impact on the PAL values. CONCLUSIONS: In the 15 y old adolescents of the two studied regions of Sweden, high and concordant levels of energy expenditure and physical activity were found.

Adolescent↗
PubMed1996

Expression of basement membrane type IV collagen chains during postnatal development in the murine cochlea.

An immunofluorescence study was performed to examine the temporal and spatial patterns of expression for the different type IV collagen chains during postnatal cochlear development. At birth, the classical chains (4A1 and 4A2) were widely expressed, while the novel chains (4A3, 4A4, and 4A5) were completely absent. Activation of the novel chains was observed at 4 days of age, with intense, widely distributed immunostaining suggesting that most of the cells in the cochlea express the novel chains at this developmental stage. From day 8 through day 14, developmental inactivation of the novel chains results in a reduction of generalized immunoreactivity with a concomitant elevation of specific staining in the membranous structures bounding the interdental cells of the spiral limbus, the inner sulcus, the basilar membrane, and in a fibrous bed of staining radiating from the spiral prominence into the region of the spiral ligament which corresponds to the location of the root cell processes. This pattern of intense immunostaining for the novel chains persists through adulthood. The classical chains are expressed in these same anatomical regions only transiently (from day 6 to day 10), after which a gradual developmental inactivation leads to the adult expression pattern where classical collagen chains are found primarily in the perineurium, in the membranes surrounding the spiral ganglion cell bodies, and in the vascular basement membranes of the spiral ligament and the stria vascularis. The complex developmental pattern of expression for the type IV collagen chains in the murine cochlea is similar to that observed in the murine kidney, which is the other major site for basement membrane pathology in Alport syndrome.

Animals↗
PubMed1996

Dietary iron intake and iron status in adolescents.

The aim of this study was to evaluate the dietary iron intake of 15-year-old adolescents from two different regions of Sweden, in relation to their iron status. The study comprised 185 boys and 209 girls, randomly selected from the official population register. The iron intake was calculated from a 7-day record, and varied between 7 and 35 and 6 and 27 mg per day for boys and girls, respectively. The daily median intakes in boys and girls were 18.7 and 14.2 mg, respectively. S-ferritin, s-iron, and s-transferrin saturation, measured in all the subjects, did not differ significantly between the two regions. However, the mean serum ferritin concentration was significantly higher in the boys (36.4 micrograms l-1) than in the girls (29.4 micrograms l-1) (p < 0.001). Low s-ferritin levels, defined as s-ferritin < 12 micrograms l-1 were found in seven boys (3.7%) and in 29 girls (13.9%). None of the adolescents had iron deficiency anaemia, defined as Hb < 110 gl-1 in combination with s-ferritin < 12 micrograms l-1. Regression and correlation analyses did not show any significant correlation between dietary iron intake and s-ferritin, or between s-ferritin and haemoglobin (Hb), MCH and MCHC. A significant correlation was found, however, between s-ferritin and transferrin saturation (p < 0.005) in both sexes. When the adolescents who still had s-ferritin < 12 micrograms l-1 at a second blood examination were given a 6 weeks trial with oral iron therapy, all of them showed an increase both in s-ferritin and in blood Hb. The 95% confidence intervals of s-ferritin for 15-year-old Swedish boys and girls were defined as 11-90 and 7-85 micrograms l-1, respectively.

Adolescent↗
PubMed1996

Food habits and energy and nutrient intake in Swedish adolescents approaching the year 2000.

In 1993-94 a nutritional survey of 15-year-old adolescents was carried out in Uppsala, a university city in eastern Sweden, and in Trollhättan, an industrial town in the western part of the country. The study was the beginning of a longitudinal nutritional survey of 193 boys and 218 girls randomly selected from the official population register. The dietary methods used were a food frequency questionnaire (FFQ) and a combined estimated and weighed 7-day dietary record. According to the FFQ both boys and girls consumed cereals, butter or margarine and something from the group meat/fish/eggs every day. Milk, milk products, sweets and snacks were consumed more than once per day. Vegetables and fruit/roots were consumed less often. There was relatively good correlation between the FFQ and the 7-day record results. The mean daily energy intakes of the 15-year-old boys and girls were 10.2 and 8.3 MJ, respectively, in Uppsala, and 9.8 and 7.4 MJ in Trollhättan. The mean daily intakes of sucrose were 74 and 58 g in boys and 64 and 52 g in girls. The average daily dietary fibre intake was 1.8 g/MJ. The daily intake of energy obtained from breakfast was 18% on weekdays and 22% on weekends; 18 and 11% from prepared lunch; 24 and 30% from dinner, 21 and 14% from light meals; and 16 and 28% from snacks, in Uppsala and Trollhättan respectively. The lowest energy intake from a prepared lunch meal was noted during weekends. On both weekdays and weekends, considerable energy was obtained from light meals and snacks. However, nearly 40% of the girls and 28% of the boys had an energy intake from fat of < 30 energy%. The mean intakes of vitamin D and selenium and, in the case of girls, iron and zinc, were below the official Swedish Nutrition Recommendations. The daily median intake of iron was 18.7 mg in boys and 14.1 mg in girls. The iron intakes varied between 6 and 35 mg per day. Low serum ferritin concentrations, defined as s-ferritin < 12 micrograms/L, were found in 7 boys (3.7% and in 29 girls (13.9%). Significant negative correlations were found between smoking and frequency of consumption of vegetables, roots, fruits and meat. A negative correlation was also found between smoking and the intake of energy and a number of nutrients. Socioeconomic factors seem to be less important for the food habits of teenagers than for those noted during childhood. Only frequent consumption of vegetables was positively correlated to the mothers' educational level.

Adolescent↗
PubMed1996

Immunohistochemical localization of basement membrane collagens and associated proteins in the murine cochlea.

Immunohistochemistry using antibodies specific for each of the basement membrane collagen chains was used to assess the location and composition of basement membranes in the mouse cochlea. The classical chains (COL4A1, 4A2) localized primarily in the osseous spiral lamina and in the capillaries of the spiral ligament. In contrast, the novel collagen chains (4A3, 4A4, and 4A5) localized to the interdental cells of the sulcus, the inner sulcus, the basilar membrane, and the region of type II fibrocytes in the spiral ligament. Antibodies against type 4A5 collagen also heavily stained the stria vascularis. Weak staining in the stria was observed with antibodies against 4A3. Basement membrane-associated proteins were also assessed. The basement membrane in the perineurium of the osseous spiral lamina immunostained using antibodies against laminin, heparan sulfate proteoglycan, and entactin. The basilar membrane contained only fibronectin in association with the novel collagen chains. The capillaries of the spiral ligament and the stria vascularis stained heavily for heparin sulfate proteoglycan and laminin. Generalized staining for laminin was observed in the spiral ligament. These results indicate that an abundance of basement membrane collagen containing extracellular matrix exists in the murine cochlea and that the composition of these matrices are surprisingly varied and tissue specific.

Animals↗
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

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↗
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↗
PubMed1994

Zinc intake, zinc status and growth in a longitudinal study of healthy Danish infants.

Mild, growth-limiting zinc deficiency might be prevalent in otherwise healthy infants according to recent studies. We examined zinc intake and status in 91 healthy term infants from birth to 12 months, as part of the Copenhagen Cohort Study on Infant Nutrition and Growth. Zinc intake was recorded monthly and the amount of zinc absorbed was estimated. These estimates were below recently published FAO/WHO/IAEA values for basal requirements in 68%, 62% and 14% of the infants at 2, 4 and 9 months of age, respectively. Serum zinc decreased significantly (p < 0.01) from 10.6 mumol/l at 6 months to 8.4 mumol/l at 9 months of age (normal range 10-18 mumol/l). Erythrocyte metallothionein values, a tentative indicator of long-term zinc status, decreased significantly from 2 to 6 months (p < 0.001) and from 6 to 9 months (p < 0.01). Serum zinc at 9 months was positively associated with growth velocity during the period from 6 to 9 months (weight: p = 0.05; knee-heel length: p = 0.002). The results provide descriptive data on zinc intake and zinc status in healthy Danish infants. Although some of our data suggest suboptimal zinc status during late infancy, evidence for this can only be obtained through a randomized intervention study.

Deficiency Diseases↗
PubMed1992

Serum bone gamma-carboxyglutamic acid protein in a longitudinal study of infants: lower values in formula-fed infants.

Bone gamma-carboxyglutamic acid protein [BGP (osteocalcin)] is a protein synthesized by osteoblasts and incorporated in the bone matrix. Serum BGP is a sensitive marker of bone formation, and it parallels the growth velocity curve during childhood and adolescence. Serum BGP was measured at the age of 2, 6, and 9 mo in a cohort study of nutrition and growth in 91 healthy infants. At 2 mo, the mean BGP value (+/- SD) was 275 +/- 87 ng/mL in infants exclusively breast-fed, and 80 +/- 44 ng/mL in formula-fed infants. At 6 mo, the values were 142 +/- 58 ng/mL and 55 +/- 30 ng/mL, and at 9 mo 75 +/- 39 ng/mL and 45 +/- 19 ng/mL in partially breast-fed and formula-fed infants, respectively. The differences were significant (p less than 0.001) at all three ages. At 2 and 9 mo, breast-milk intake was measured by test-weighing. Serum BGP was positively correlated to breast milk intake (mL/kg body wt) at 2 mo (r = 0.59, p less than 0.001) and 9 mo (r = 0.41, p = 0.06). When breast-feeding was stopped, the high BGP concentrations were not sustained. There were no significant differences in linear growth velocity between breast-fed and formula-fed infants and no correlation between BGP values and linear growth velocity. We speculate that either a factor in human milk or the level of minerals in human milk causes the high BGP values. Moreover, if the higher values are associated with increased osteoblast activity, then the remodeling or the mineralization of bone might be different in infants not being breast-fed.

Age Factors↗