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- Bergström, Erik, 1944-
(författare)
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Cardiovascular risk indicators in adolescents : the Umeå youth study
- 1995
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerotic cardiovascular diseases (CVD), particularly coronary heart disease (CHD) and cerebrovascular disease, are today major causes of death in the industrialised parts of the world. There are evidence to suggest that the atherosclerotic process starts in childhood, implying that preventive measures should be implemented already in children and adolescents.The aim of this study was to examine CVD risk indicators and their determinants in healthy Swedish adolescents. The study population comprised 14- and 17-year-old boys and girls (n=1032), in the dty and surroundings of Umeå in northern Sweden.Biochemical, anthropometric, and physiological parameters associated to CVD (s- lipoproteins and s-apolipoproteins, s-insulin, s-ferritin, anthropometric measurements, blood pressure, and physical fitness) were evaluated in relation to family history of CVD, weight and length at birth, infant feeding regimen, physical growth during infancy and childhood, current diet, physical activity, smoking, and educational level and occupation of the parents.The main findings of the study were that, on average, total serum cholesterol (TC) values in boys and girls were at the same level as reported from other European countries. A family history of CVD, short duration of breast feeding, low attained height during infancy and childhood, high body mass index (BMI), and low physical fitness were all associated with an unfavourable serum lipid profile. The findings also showed that features typical of the insulin resistance syndrome are present already in adolescents. In boys, iron stores, estimated by serum ferritin, were related to BMI and physical fitness, in a similar way as well established CVD risk indicators. Compared to previous dietary studies in Sweden, mean relative (energy %) fat intake had decreased substantially although the mean relative intake of saturated fat was still rather high. For both boys and girls, reported relative energy intake (energy intake/estimated energy expenditure) decreased with increasing level of BMI. Furthermore, daily smoking was more common among adolescents from families with low socio-economic status (SES) but was most strongly associated to smoking in peers. Tobacco use was considerably higher among adolescents attending vocational programs at secondary high school as compared to theoretical programs. Daily smokers had a more unfavourable serum lipid profile compared to non-smokers. Low socio-economic status of the parents was related to higher BMI and low educational level to higher dietary fat intake in both boys and girls.In conclusion, the findings of the study show that parameters linked to adult CVD when examined in adolescents, are related to family history, infant nutrition, previous physical growth, current body composition, physical fitness, physical activity, smoking, and social status and educational level of the parents.
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| 12. |
- Björmsjö, Maria, 1978-
(författare)
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Clinical effects of reduced iron content and fortification with bovine lactoferrin in infant formula
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Breast milk, with its complex, individual and over time adapting composition, is considered the optimal source of nutrition for infants during the first months of life. Two possible contributing factors to the benefits of breastfeeding compared to infant formula-feeding are the differences in iron and lactoferrin (Lf) concentrations between breast milk and infant formula. The overall purpose of the LIME (a Swedish acronym) study was to add knowledge on how to reduce the gap in health and development between breastfed and formula-fed infants. The aim of this double-blinded controlled trial, and doctoral thesis, was to investigate how added bovine lactoferrin and reduced iron concentration in infant formula affect health and development.Methods: Recruitment took place from June 2014 to June 2018. With equal gender distribution, healthy term Swedish formula-fed infants (n=180) were randomly assigned, from 6 weeks to 6 months of age, to receive a low iron formula (2 mg/L) with bovine Lf (1.0 g/L) (Lf+, n=72), a low iron formula without Lf (Lf-, n=72) or a control standard formula with 8 mg/L iron and no Lf (CF, n=36). Additionally, 72 breastfed infants were recruited as a reference (BF) group. Blood samples were drawn at 4, 6, and 12 months. Primary outcomes were cytokine levels and iron status. Secondary outcomes were growth, gastrointestinal symptoms, infection-related morbidity and treatments, antibody response to vaccines and cognitive development.Findings: All explored outcomes were unaffected by Lf fortification and the two low iron groups (Lf+ and Lf-) were combined and compared to the CF group. At 6 months of age the TGF-β2 levels were lower among the low iron groups and more similar to the BF infants. No other significant differences in cytokine levels were observed. There was a trend of lower geometric mean of ferritin at 4, 6, and 12 months for the combined low iron groups compared to the CF group (67.7 vs 88.7, 39.5 vs 50.9, and 20.5 vs 25.1 μg/L, respectively, p=0.054, p=0.056, and p=0.082). No similar trends or significant differences were found for any of the other iron status indicators, except for hepcidin at 12 months with lower levels in the low iron group compared to CF (37.8 vs 49.4 ng/mL, p=0.027). Overall, infants fed low iron formula had iron status indicators closer to the breastfed reference group and the prevalence of iron deficiency (ID) and iron deficiency anemia (IDA) was generally low with no significant differences among the intervention groups.There were no clinically relevant effects of the interventions on growth, gastrointestinal symptoms, infection-related morbidity, vaccine antibody response or neurocognitive development.In secondary analyses, the present study confirmed previous results of higher cognitive scores among breastfed infants compared to formula-fed and observed an unexpected lower IgG response to vaccines against Hib and Diphtheria.Conclusion: Adding bovine lactoferrin did not affect any of the clinical outcomes explored. Lowering infant formula iron concentration from 8 to 2 mg/L minimally reduced iron stores to levels closer to breastfed infants but did not increase the risk of ID/IDA during the first year of life. Consequently, 2 mg/L is a sufficient level of iron fortification during the first six months of life in a population with low risk of ID. Both adjustments are considered safe with no observed adverse effects.
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| 20. |
- Hernell, Olle, 1945-
(författare)
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Den humana mjölkens lipaser : egenskaper och fysiologiska aspekter
- 1974
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I avhandlingen visas att: Human mjölk innehåller två lipaser. Det ena är ett serum-stimulerat lipas (lipoprotein lipas). Lipoprotein lipaser är enzymer som har en central roll i den normala katabolismen av de triglyceridrika plasma- lipoproteinerna. Lipaset har sannolikt inte någon fysiologisk funktion i mjölken. En metod beskrivs med vilken lipaset har renats ca 9 500 gånger från mjölk. Det serum-stimulerade lipaset från human mjölk har de klassiska egenskaperna för ett serum-stimulerat lipas (lipoprotein lipas). Med en immunologisk metod visas att lipaset korsreagerar med motsvarande lipaser i bovin mjölk och human postheparin plasma. Slutsatsen är att det serum-stimulerade lipaset i human mjölk är väl värt att studera eftersom det mycket väl kan ha många egenskaper gemensamma med de fysiologiskt aktiva och viktiga humana serum-stimulerade lipaserna. Det andra lipaset i human mjölk, det gallsalt-stimulerade lipaset, har en låg substratspecificitet. Gallsalter stimulerar enzymaktiviteten mot alla substrat som testats. Mot mjölkens egna triglycerider är lipaset helt inaktivt i frånvaro av gallsalter. I närvaro av gall- salter spjälkar lipaset alla tre esterbindningarna i triglycerid- molekylen så att slutprodukterna blir fria fettsyror och glycerol. Gallsalter skyddar lipaset mot olika typer av inaktivering, t ex mot inaktivering av tarmens proteinnedbrytande enzymer. Det är sannolikt att gallsalternas effekt beror på att de direkt interagerar med enzymproteinet. Lipaset visas ha sådana egenskaper att det väsentligt skulle kunna bidraga till den spjälkning av mjölktriglyceriderna som sker i tarmen hos den nyfödde.
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