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- Särnblad, Stefan, 1963-
(författare)
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Body Composition in Adolescents with Type 1 Diabetes : Aspects of Glycaemic Control and Insulin Sensitivity
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Excessive weight gain has frequently been reported in adolescents with type 1 diabetes, especially in girls. In general, puberty is associated with reduced insulin sensitivity that is further diminished by overweight. The causes and consequences of excessive weight gain in adolescents with type 1 diabetes are not fully understood. The studies described in this thesis addressed body composition in adolescents with type 1 diabetes and the relationships between physical activity, energy intake and changes in body composition. Furthermore, the effect of metformin as additional therapy on glycaemic control and insulin sensitivity was examined in a randomised placebo-controlled study. Body mass index (BMI) and percentage body fat (%BF) were significantly higher in girls with type 1 diabetes compared to healthy control girls. Mean HbA1c during puberty, but not mean insulin dose, was positively related to BMI at the age of 18 in girls with diabetes. A centralised fat distribution was associated with poor glycaemic control, increased daily dosage of insulin and elevated cholesterol and triglyceride levels. Neither total physical activity nor total energy intake differed between adolescent girls with type 1 diabetes and healthy age-matched control girls. A high dietary fat intake was positively related to gain in %BF in girls with type 1 diabetes. Additional therapy with metformin for three months improved glycaemic control and peripheral insulin sensitivity in adolescents with poorly controlled type 1 diabetes. The improvement in glycaemic control was related to insulin sensitivity at baseline, implying that the most insulin resistant subjects benefited most from the metformin therapy. It is concluded that the excessive weight gain observed in girls with type 1 diabetes is mainly attributable to an increased fat mass and that dietary fat intake is of importance for this gain in body fat. Additional treatment with metformin improves glycaemic control in adolescents with poorly controlled type 1 diabetes.
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| 2. |
- Tuvemo, Torsten, et al.
(författare)
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Final height after combined growth hormone and GnRH analogue treatment in adopted girls with early puberty
- 2004
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 93:11, s. 1456-1462
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Tidskriftsartikel (refereegranskat)abstract
- Background: Girls adopted from developing countries often have early or precocious puberty, requiring treatment with gonadotrophin-releasing hormone (GnRH) analogues. During such treatment, decreased growth velocity is frequent. Aim: To study whether the addition of growth hormone (GH) to GnRH analogue treatment improves final height in girls with early or precocious puberty. Methods: Forty-six girls with early or precocious puberty (age ≤9.5 y) adopted from developing countries were randomized for treatment for 2-4 y with GnRH analogue, or with a combination of GH and GnRH analogue. Results: During treatment, the mean growth velocity in the GH/GnRH analogue group was significantly higher compared to the control group. Combined GH/GnRH analogue treatment resulted in a higher final height: 158.9 cm compared to 155.8 cm in the GnRH analogue-treated group. Three out of 24 girls (13%) in the combined group and nine of the 22 girls (41%) treated with GnRH analogue alone attained a final height below -2 standard deviation scores (SDS). Conclusion: The difference between the two groups is statistically significant, and possibly of clinical importance. A future challenge is to identify a subgroup with clinically significant advantage of GH addition to GnRH analogue treatment. Being very short on arrival in Sweden and being short and young at start of treatment are possible indicators.
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| 3. |
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| 4. |
- Ekelund, Ulf, 1960-, et al.
(författare)
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Physical activity but not energy expenditure is reduced in obese adolescents : a case-control study
- 2002
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 76:5, s. 935-941
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The influence of physical activity on body weight in children and adolescents is controversial.OBJECTIVE: The objective was to test the hypothesis that the intensity and duration of physical activity differ between obese and normal-weight adolescents, with no difference in estimated energy expenditure.DESIGN: We compared physical activity in 18 (8 males, 10 females) obese [body mass index (in kg/m(2)) > 30] adolescents (14-19 y) with that in a matched, normal-weight (BMI < 27) control group. Total energy expenditure (TEE) was measured with the doubly labeled water method, and physical activity was measured simultaneously by accelerometry. The physical activity level was determined as the ratio of TEE to the resting metabolic rate (RMR) and activity energy expenditure as 0.9 TEE minus RMR. Accelerometry data included total physical activity (counts x min(-1) x d(-1)), accumulated and continuous duration of activity, and continuous 10-min periods of physical activity of moderate intensity.RESULTS: There was no significant difference in adjusted (analysis of covariance) TEE, RMR, or AEE between groups. The physical activity level was significantly lower (P < 0.05) in the obese group. No sex x group interaction was observed. Differences in total physical activity (P < 0.001), accumulated time (P < 0.05), continuous time (P < 0.01), and continuous 10-min periods of physical activity of moderate intensity (P < 0.01) were observed between groups.CONCLUSIONS: Obese adolescents are less physically active than are normal-weight adolescents, but physical activity-related energy expenditure is not significantly different between groups. The data suggest that physical activity is not necessarily equivalent to the energy costs of activity.
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| 6. |
- Pidokrajt, Narit, 1979-, et al.
(författare)
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Geometry of black hole thermodynamics
- 2003
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Ingår i: General Relativity and Gravitation. - Germany : Springer. - 0001-7701 .- 1572-9532. ; 35:10, s. 1733-1743
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Tidskriftsartikel (refereegranskat)abstract
- The Hessian of the entropy function can be thought of as a metric tensor on the state space. In the context of thermodynamical fluctuation theory Ruppeiner has argued that the Riemannian geometry of this metric gives insight into the underlying statistical mechanical system; the claim is supported by numerous examples. We study this geometry for some families of black holes. It is flat for the BTZ and Reissner-Nordstrom black holes, while curvature singularities occur for the Reissner-Nordstrom-anti-de Sitter and Kerr black holes.
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| 7. |
- Schölin, Anna
(författare)
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Diabetes in Young Adults : Remission, β-cell function and markers of inflammation
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Type 1 diabetes is caused by immuno-mediated β-cell destruction leading to insulin deficiency and hyperglycaemia. The decline in β-cell function and the clinical course after diagnosis vary. Whether the process of destruction of the β-cells is associated with markers of a non-specific inflammatory response is unknown. The aims of these studies were to identify factors of importance for clinical remission (low insulin need and normoglycaemia) and long-term β-cell function and estimate the degree of non-inflammatory response in type 1 diabetes in young adults. Clinical remission and β-cell function eight years after diagnosis were assessed and related to clinical, biochemical and immunological variables at diagnosis, including islet autoantibodies [ICA, GADA, IA-2A]. Markers of low-grade inflammation in plasma [CRP and IL-6] were estimated and the concentrations were related β-cell function [plasma C-peptide], glycaemic control and autoimmunity at diagnosis and the first year thereafter. The results showed that clinical remission occurred in about half of the patients with newly diagnosed type 1 diabetes. Preserved β-cell function eight years after diagnosis was observed in 16% of the patients classified at diagnosis as having autoimmune type 1 diabetes. Duration of remission was dependent on BMI, degree of metabolic derangement and presence of GADA at diagnosis. BMI at diagnosis was also of importance for preserved β-cell function after eight years of the disease, as were the amount of islet antibodies and presence of ICA. Elevated CRP levels were noted in the majority of cases at diagnosis and both CRP and IL-6 concentrations were stable the first year after clinical diagnosis. High concentrations of CRP and IL-6 did not relate to β-cell destruction or the degree of autoimmunity. CRP concentrations were higher in islet antibody negative than in positive patients. CRP also correlated positively to BMI, C-peptide at 12 months and to increasing HbA1c between six and 12 months. In general, females had shorter remissions, lower concentrations of serum bicarbonate and higher levels and prevalence of GADA at diagnosis, compared to males. Females also had higher HbA1c and CRP values the first year after diagnosis. In summary, BMI at diagnosis is a strong predictor of duration of remission and preservation of β-cell function. Elevated CRP concentrations are correlated to factors linked rather to insulin resistance than to β-cell destruction. Females appear to have a more acute onset and a more severe course of the disease than males.
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