| 1. |
- Berhan, Yonas, 1970-
(författare)
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Epidemiological studies of childhood diabetes and important health complications to the disease
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background and aims: The overall aim of this thesis was to increase knowledge regarding the occurrence of childhood onset T1D and T2D in Sweden and in relation to that describe and elucidate important aspects on two grave complications to diabetes; end-stage renal disease (ESRD) and mortality. The two first studies included in this thesis aimed to describe and analyze the cumulative incidence of childhood onset T1D in Sweden and to assess the occurrence of undetected T2D in Swedish children. The aim with the third study was to describe the cumulative incidence of ESRD, and to analyze how ESRD risk differs with age at-onset and sex. The aim of the fourth study was to show how parental socioeconomic status (SES) affects all cause mortality in Swedish patients with childhood onset T1D.Study populations: The foundation for the studies on T1D was data from the Swedish Childhood Diabetes Registry (SCDR). When studying ESRD we also included adult onset T1D cases from the Diabetes Incidence Study in Sweden (DISS). The study on T2D was a population-based screening study where BMI was measured in 5528 school-children and hemoglobin A1c was measured in children with overweight according to international age and sex specific BMI cut-offs. To study ESRD and mortality, we linked the SCDR to various nationwide registers containing individual information on SES, mortality and ESRD.Results: The incidence rates of childhood onset T1D has continued to increase in Sweden 1977–2007. Age- and sex-specific incidence rates varied from 21.6 (95% CI 19.4–23.9) during 1978–1980 to 43.9 (95% CI 40.7– 47.3) during 2005–2007. Cumulative incidence by birth-cohorts has shifted to a younger age at-onset over the first 22 years of incidence registration. From the year 2000 there was a significant reverse in this trend (p<0.01). In contrast to the increase of T1D, we found no evidence of undetected T2D among Swedish school children. Despite a relatively high incidence in T1D in Sweden there is low cumulative incidence of ESRD, 3.3% at maximum 30 years of duration. We found difference between the sexes regarding long-term risk of developing ESRD that was dependent on the age at onset of T1D. When analyzing how socioeconomic status affects mortality in different age at death groups, we found that having parents that received income support increased mortality up to three times in those who died after 18 years of age.Conclusion: The incidence of childhood onset T1D continued to increase in Sweden 1978-2007. Between the years 1978-1999 there was a shift to a younger age at-onset, but from the year 2000 there is a change in this shift indicating a possible trend break. The prevalence of T2D among Swedish children up to 12 years of age is probably very low. There is still a low cumulative incidence of T1D associated ESRD in Sweden. The risk of developing ESRD depends on age at-onset of T1D, and there is a clear difference in risk between men and woman. Excess mortality among subjects with childhood onset T1D still exists, and low parental socioeconomic status additionally increased mortality in this group.
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| 2. |
- Persson, Emma, 1981-
(författare)
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Causal inference and case-control studies with applications related to childhood diabetes
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contributes to the research area of causal inference, where estimation of the effect of a treatment on an outcome of interest is the main objective. Some aspects of the estimation of average causal effects in observational studies in general, and case-control studies in particular, are explored.An important part of estimating causal effects in an observational study is to control for covariates. The first paper of this thesis concerns the selection of minimal covariate sets sufficient for unconfoundedness of the treatment assignment. A data-driven implementation of two covariate selection algorithms is proposed and evaluated.A common sampling scheme in epidemiology, and when investigating rare events, is the case-control design. In the second paper we study estimators of the marginal causal odds ratio in matched and independent case-control designs. Estimators that, under a logistic regression model, utilize information about the known prevalence of being a case is examined and compared through simulations.The third paper investigates the particular situation where case-control sampled data is reused to estimate the effect of the case-defining event on an outcome of interest. The consequence of ignoring the design when estimating the average causal effect is discussed and a design-weighted matching estimator is proposed. The performance of the estimator is evaluated with simulation experiments, when matching on the covariates directly and when matching on the propensity score.The last paper studies the effect of type 1 diabetes mellitus (T1DM) on school achievements using data from the Swedish Childhood Diabetes Register, a population-based incidence register. We apply theoretical results from the second and third papers in the estimation of the average causal effect within the T1DM population. A matching estimator that accounts for the matched case-control design is used.
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| 3. |
- Toppe, Cecilia, 1974-
(författare)
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End stage renal disease in type 1 diabetes : time trends and risk factors
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background and aims: Sweden has a high incidence of type 1 diabetes (T1D) and the incidence is increasing worldwide. The incidence is now twice as high as when the registration of childhood onset T1D in Sweden started in 1977. One of the major risk factors for developing late complications such as renal failure (ESRD) is duration of T1D. With a disease onset early in life this could lead to young patients with serious complications. It is therefore of interest to follow these patients to see how the risk for complications develops over time. In the first study, time trends in onset of ESRD due to diabetes (type 1 and 2) and other causes of kidney failure were studied as well as the age at onset of ESRD. To follow up on this, the aim of the second study was to look at cumulative incidence in ESRD and analyse possible time trends and gender differences in a younger diabetes population with known T1D duration. An earlier study had shown a low incidence of ESRD and now 8 more years of follow up could be added. Besides genetics, metabolic control is a factor with strong impact on the future risk of complications. The social environment of the child and adolescent with diabetes influence the understanding and management of the disease and hence the blood glucose control. Social vulnerability and/or low education imposes even more stress on the individual which could negatively influence disease management. The aim of the third study was therefore to study the impact of socio-economic status (SES) on the risk of developing ESRD in the young diabetes population. The aim of the fourth study was to analyse time trends in the treatment choices once the patients develop ESRD, the survival and cause of death in treatment and how it has developed over time.Study population: In all studies, data from the Swedish Renal Register (SRR) were used. The data on the T1D patients with onset before the age of 15, used in studies II-IV, came from the Swedish Childhood Diabetes Register (SCDR). In study II we also retrieved data from the Swedish National Diabetes Register (NDR) and the Diabetes Incidence Study in Sweden (DISS). All registers have national coverage. The diabetes registers were linked to the SRR to find the patients who had developed ESRD. In study III we used the linkage between the SCDR, the SRR and Longitudinal integration database for health insurance and labour market studies (LISA).Results: Even though the incidence of ESRD in Sweden remained stable, the incidence of ESRD due to T1D decreased over the studied years, 1991-2010. We did not see a concurrent change for T2D. The age when the T1D patients developed ESRD had increased by 3 years and this was not seen in patients with other causes of ESRD. For patients in the SCDR the increase in age was almost 6 years. The cumulative incidence of ERSD in Sweden due to T1D is still low, 5.6% at a maximum follow up of 38 years (median 23). The incidence of ESRD is decreasing when comparing onset of T1D in the 1970´s and 80´s to onset in the 90´s, even when adjusting for T1D duration. Once they had developed ESRD, the survival in renal replacement therapy (RRT) had also improved over the years. The longest survival was seen after receiving a kidney transplant which about 50% of the patients do.When analysing social risk factors for development of ESRD we found that the educational level of both parents, but especially the mothers, affected the child’s risk of developing ESRD. The strongest association of education however was seen in the T1D patients own education. There was also an increased risk of developing ESRD if any or both of the parents had received income support.Conclusion: The incidence of ESRD due to T1D is decreasing in Sweden and the age at onset of ESRD has increased by at least 3 years. There was a significant decrease in development of ESRD over time. The patients have a longer survival once in RRT today and many of them are transplanted, further improving their survival. Growing up in families with a lower SES increases the risk of later developing ESRD, a finding worthy of recognition in the clinical setting.
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| 4. |
- Viklund, Gunnel, 1951-
(författare)
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Education for Teenagers with Type 1 Diabetes
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Education for teenagers with diabetes has had limited effects to date, especially regarding metabolic control. The development had been towards more patient-centred approaches, like empowerment, motivational interviews and family behavioural programmes. A patient-centred approach means that the patient is expected to take control of the management of the disease. The empowerment approach has been implemented in adults with diabetes, with some positive results.The aims of this thesis were to evaluate empowerment group education and education in a camp setting, and to validate the “Check your health” instrument which can be used to assess the effects of such education programmes on perceived health and the burden of diabetes.Thirty-two teenagers between 12 and 17 years of age were randomized to either an intervention group or a wait-listed control group. The intervention consisted of six group sessions with an empowerment approach as the theoretical frame. Thirty-one of the teenagers were interviewed two weeks after the empowerment education programme was completed.The programme did not have any positive effect on metabolic control between-groups, but within groups HbA1c and readiness to change increased. According to the definition of empowerment, which pinpoints decision-making, the interviews were analysed with that in focus. In the interviews the teenagers described five categories they perceived as important for decision-making competence: cognitive maturity, personal qualities, experience, social network and parent involvement. Parent involvement was described as both constructive and destructive. These categories were interpreted in the overall theme that “teenagers deserve respect and support for their shortcomings during the maturity process”.Ninety teenagers between 14 and 17 years of age attended education in a camp setting and were compared to a reference group, who had declined participation. The camp did not have any positive effect on metabolic control, but the frequency of insulin pump use after camp education increased. In a cross-sectional comparison, the campers had more positive attitudes towards diabetes and self-care than the non-campers did.The “Check your health” instrument was tested for reliability and validity in 199 teenagers between 12 and 17 years of age. The instrument was found to be reliable and valid for use on a group level in teenagers with diabetes.In conclusion, empowerment education programmes should be tailored to suit young people with diabetes, and should preferably be integrated into routine care. Teenagers who prefer individual education may be offered an individual education plan. Parents should be involved in all education of teenagers with diabetes, with the purpose of increasing teamwork and decreasing control and conflict. Continued assessment of teenagers perceived health and perceived burden of diabetes can be carried out using the “Check your health” instrument.
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| 5. |
- Pundziute-Lyckå, Auste, 1968-
(författare)
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Incidence trends and environmental determinants of type 1 diabetes in Lithuania and Sweden
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Variation of diabetes incidence over time in countries with different incidence levels and socio-economic conditions, and in an age span beyond the childhood years, may give clues for diabetes causes.Materials: Data from prospective type 1 diabetes registers in Sweden and Lithuania in children (0-14 years) and young adults (15-34 and 15-39 years, respectively). Number of infections recorded in health care booklets (117 cases; 270 controls); interview about the dietary intake one-year before the diagnosis and routinely recorded growth data (99 cases; 180 controls).Results: The incidence of type 1 diabetes in Sweden and Lithuania differed most in the younger age groups, 28.9 and 7.5/100,000/year in 0-14-year group, respectively. During 1983-2000 incidence increased in 0-14-year old children in both countries, but the pattern of change differed. During 1983-1998 the incidence increased in Swedish children, but tended to decrease in young adults, with no increase in the age group below 35 years, indicating that the increase of childhood diabetes may be due to a shift towards a younger age at diagnosis. Within a low-incidence country Lithuania there was an urban-rural gradient of incidence, especially in the younger age groups, that seemed to follow poverty distribution: incidence in the 0-39-year group was 7.1, 9.0 and 8.8/100,000/year in rural areas, towns and cities, respectively, p<0.001.Exposure to one or more non-specific infection during the first half-year of life reduced diabetes risk: odds ratios (95%-CI) in 0-14 and 5-14-year groups were (0.60; 0.37-0.98) and (0.47; 0.26-0.87), respectively. Higher energy intake and weight-for-age were independent diabetes risk factors: odds ratios for medium and high levels of energy were 1.33 (0.52-3.42) and 5.23 (1.67-16.38), and for weight-for-age 3.20 (1.30-7.88) and 3.09 (1.16-8.22), respectively. High intake of carbohydrates, disaccharides and sucrose in particular, increased diabetes risk independently of the high intake of energy.Conclusion: Environmental factors associated with socio-economic conditions in childhood may be important for the occurrence of type 1 diabetes. Lack of exposure to microbial antigens early in life, higher intake of energy and more rapid growth may contribute to the increase of childhood-onset diabetes observed in many countries.
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