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Dissertations

On this page, you will find summaries of the latest dissertations from Folkhälsan Research Center, providing insights into recent research. Further down, you will also find a comprehensive list of past dissertations, including links to the full texts.

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Cerebral small vessel disease and stroke in type 1 diabetes – The impact of blood pressure, haptoglobin genotype, and diabetic retinopathy

Marika Eriksson: The results suggest that cerebrovascular disease in type 1 diabetes is linked to microvascular damage and that the health of the eye’s blood vessels may reflect the health of the brain’s blood vessels.

Marika Eriksson: Cerebral small vessel disease and stroke in type 1 diabetes – The impact of blood pressure, haptoglobin genotype, and diabetic retinopathy

Cerebrovascular disease, such as stroke, is a severe complication of type 1 diabetes, with a high risk of disability and mortality. It is not fully clear how cerebrovascular complications develop, but diabetes is suggested to damage the brain’s small vessels similarly to other diabetic microvascular damage.

This study aimed to assess factors associated with early signs of cerebrovascular brain damage in asymptomatic individuals with type 1 diabetes, as well as risk markers for the development of stroke in these individuals.

Our results showed that cerebral small vessel disease is associated with elevated nocturnal blood pressure in type 1 diabetes. We also found cerebral small vessel diseases to be more common with increasing severity of diabetic eye disease and that severe diabetic eye disease marked an increased risk of having a stroke.

The results suggest that cerebrovascular disease in type 1 diabetes is linked to microvascular damage and that the health of the eye’s blood vessels may reflect the health of the brain’s blood vessels.

Marika Eriksson: Cerebral small vessel disease and stroke in type 1 diabetes – The impact of blood pressure, haptoglobin genotype, and diabetic retinopathy. 2025.

Sleep habits of Finnish preschoolers: Associations with diet and weight

Anna Abdollahi: Children with a later chronotype at preschool age were associated with greater weight gain over the eight-year follow-up period.

Anna Abdollahi: Sleep habits of Finnish preschoolers: Associations with diet and weight

Having a later chronotype often increases the risk of circadian misalignment, as social demands often conflict with internal biological clocks. Among adolescents and adults, a later chronotype has been associated with less healthy sleep patterns, poorer diet quality, increased weight status, and reduced overall well-being. However, little research has focused on younger children, leaving it unclear when these associations begin to develop.

Using data from the DAGIS project, we employed novel, data-driven sleep estimation methods with actigraphy data to assess several sleep measures, including chronotype.

While children with a later chronotype were not associated with higher weight outcomes during preschool age, they were associated with less healthy diet quality, including lower vegetable and higher sugary food consumption. Furthermore, children with a later chronotype at preschool age were associated with greater weight gain over the eight-year follow-up period.

In conclusion, our findings suggest that preschool age may be a critical period when children vulnerable to circadian misalignment potentially begin to experience its negative effects. More research is needed to understand sleep, diet, and weight trajectories in children and the early role of circadian misalignment in weight development.

My dissertation also explored the associations between other sleep measures (duration, timing, quality) with diet (energy intake, macronutrient intake, and food consumption), and weight outcomes.

Anna Abdollahi: Sleep habits of Finnish preschoolers: Associations with diet and weight. 2025.

Frailty and functioning as determinants of healthcare use

Jenni Ikonen: We found that frailty was associated with greater specialized and primary healthcare service use. Furthermore, frailty and its faster progression rate were associated with increased medical imaging service use and costs.

Jenni Ikonen: Frailty and functioning as determinants of healthcare use

The aging global population is creating new demands for healthcare systems. Understanding factors that drive healthcare use is essential for planning preventative measures and adapting the services to meet the needs of the aging populations. Frailty, characterized by vulnerability to stressors and impaired recovery, is proposed to explain health differences among older adults, while maintaining functioning is central to healthy aging. Therefore, we aimed to investigate whether frailty and functioning would be associated with healthcare use.

We found that frailty was associated with greater specialized and primary healthcare service use. Furthermore, frailty and its faster progression rate were associated with increased medical imaging service use and costs. Participants with poorer physical functioning had higher utilization rates of specialized healthcare services compared to participants with better functioning. Poorer mental functioning, in turn, was associated with a higher number of first outpatient visits. In conclusion, public health interventions should be considered to prevent frailty and support functioning among aging populations.

Jenni Ikonen: Frailty and functioning as determinants of healthcare use. 2024.

Estrogen biosynthesis in subcutaneous and visceral adipose tissue in women

Natalia Hetemäki: We found that considerable amounts of estrogens were produced in fat already before menopause. After menopause, the role of visceral adipose tissue in the production of estrogens was highlighted.

Natalia Hetemäki: Estrogen biosynthesis in subcutaneous and visceral adipose tissue in women

Adipose tissue, or fat tissue, is important in the production of sex steroids like estrogens and androgens, especially after menopause. The distribution of adipose tissue in women changes over the course of their reproductive life – at menopause, the relative amount of visceral compared to subcutaneous adipose tissue increases, and this leads to an increased risk of metabolic disorders such as cardiovascular disease and type of 2 diabetes. Menopausal hormone therapy seems to mitigate these changes.

We studied changes taking place in the biosynthesis of estrogens in subcutaneous and visceral adipose tissue in women before and after menopause. We also studied how the production of estrogens and androgens in fat is affected by the use of menopausal hormone therapy.

We found that considerable amounts of estrogens were produced in fat already before menopause. After menopause, the role of visceral adipose tissue in the production of estrogens was highlighted. Users of menopausal hormone therapy had high tissue to serum concentrations of estrogens and increased local estrogen-to-androgen ratios in adipose tissue compared to women without hormone therapy. These changes could play a role in the preventive effect that menopausal hormone therapy has on menopause-associated visceral adiposity.

Natalia Hetemäki: Estrogen biosynthesis in subcutaneous and visceral adipose tissue in women. 2024.

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Genetic and Functional Studies of Ultra-Rare Diseases

Johanna Lehtonen: A striking binding pattern was unraveled: the ends of the nebulin super-repeat region bound strongly to filamentous actin, whereas the central part bound weakly.

Johanna Lehtonen: Genetic and Functional Studies of Ultra-Rare Diseases

In my doctoral thesis, I investigated the genetic inheritance of ultra-rare diseases in twelve families using different high-throughput sequencing (HTS) methods. Of those methods, a technology called linked-read sequencing was studied in more detail.

The study showed that linked-read sequencing can solve the haplotype information (in other words, the information which set of variants are inherited from each parent) even for very large muscle disease genes if the DNA meets quality standards.

These different sequencing strategies resulted in identifying a molecular genetic diagnosis in four families when variants in ACTA1, CCDC88A, MYH3, and TPM3 genes were identified. The thesis work also included functional laboratory studies: the disease-causing mechanisms of the identified CCDC88A variants were evaluated using patient cells.

Additionally, the binding ability of wild-type nebulin and actin muscle sarcomere proteins was investigated. A striking binding pattern was unraveled: the ends of the nebulin super-repeat region bound strongly to filamentous actin, whereas the central part bound weakly.

Johanna Lehtonen: Genetic and Functional Studies of Ultra-Rare Diseases. 2024.

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Feline personality and problematic behaviour – Associations with demographic, genetic, and environmental factors

Salla Mikkola: The most important factors associating with the problematic behaviour were cat's breed and personality traits, especially fearfulness and sociability.

Salla Mikkola: Feline personality and problematic behaviour – Associations with demographic, genetic, and environmental factors

Like dogs, cats can have problematic behaviour. Problematic behaviour is an important subject to study as it can decrease the welfare of both the owner and the cat. We targeted four common problems in cats and studied which demographical, personality and environmental factors associate with them. In addition, we investigated the structure of personality in cats and validated the data with multiple methods.

The results show that the problematic behaviours are complex and affected by various variables. The most important factors associating with the problematic behaviour were cat's breed and personality traits, especially fearfulness and sociability. The gathered data was proven to be valid and reliable.

Salla Mikkola: Feline personality and problematic behaviour – Associations with demographic, genetic, and environmental factors. 2024.

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Biomarkers of the Gut Fungal and Bacterial Composition in Inflammatory Bowel Disease

Rebecka Ventin-Holmberg: The results showed that treatment responses could be accurately predicted even before treatment initiation, and that gut microbiota health improved during successful treatment.

Rebecka Ventin-Holmberg: Biomarkers of the Gut Fungal and Bacterial Composition in Inflammatory Bowel Disease

Research on biomarkers of the gut microbiota may support the important development of precision and personalization of treatment and indication of disease predisposition. Here biomarkers to predict inflammatory bowel disease treatment response were examined and inflammatory-linked biomarkers were investigated from the fungal microbiota of antibiotic-treated infants.

The results showed that treatment responses could be accurately predicted even before treatment initiation, and that gut microbiota health improved during successful treatment. Additionally, significant changes were observed in the fungal gut microbiota of infants exposed to antibiotics.

Rebecka Ventin-Holmberg: Biomarkers of the gut fungal and bacterial composition in inflammatory bowel disease. 2024.

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Simple devices for single-cell trapping and droplet digital PCR

Pinja Elomaa: The study presents promising advancements in droplet technology, offering cost-efficient and fast solutions for single-cell capturing and nucleic acid amplification, with potential future commercial applications in various settings, from field laboratories to clinical facilities.

Pinja Elomaa: Simple devices for single-cell trapping and droplet digital PCR

Droplet technology holds immense potential in various biomedical applications, from single-cell techniques to ddPCR, wherein samples are compartmentalized into numerous droplets housing individual cells or RNA/DNA strands.

Despite existing advanced devices, many are costly and complex. This study focused on advancing droplet-based systems for biomedical research and diagnostics, aiming to develop accessible and portable chips suitable for rapid diagnostics.

Experimental results demonstrate efficacious isolation of single cells as well as isolation and amplification of RNA strands within droplets, particularly showcasing efficient nucleic acid amplification of the SARS-CoV-2 virus using the isothermal amplification reaction, SIBA (Aidian).

Overall, the study presents promising advancements in droplet technology, offering cost-efficient and fast solutions for single-cell capturing and nucleic acid amplification, with potential future commercial applications in various settings, from field laboratories to clinical facilities.

Pinja Elomaa: Simple devices for single-cell trapping and droplet digital PCR. 2024.

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Growth, puberty, gynecological health, and fertility in women with APECED

Viivi Saari: We showed that subjects with APECED have progressive growth impairment through prepuberty until the attainment of adult height.

Viivi Saari: Growth, puberty, gynecological health, and fertility in women with APECED

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare genetic disorder arising from mutations in the autoimmune regulator (AIRE) gene.

AIRE participates in the regulation of autoimmunity. Clinical presentation of APECED is variable, with over 20 different disease manifestations recognized. In women, primary ovarian insufficiency is one of the most common endocrine manifestations.

Our primary objectives were to investigate growth patterns of patients with APECED from birth until the attainment of adult height and to explore effects of APECED on pubertal development, sexual health, and fertility in women with APECED.

We showed that subjects with APECED have progressive growth impairment through prepuberty until the attainment of adult height. Primary ovarian insufficiency often develops shortly after puberty leading to sex hormone deficiencies and a decline in fertility.

Pregnancies in women with APECED are rare, but pregnancy outcomes are usually favourable for both the mother and the infant.

Viivi Saari: Growth, puberty, gynecological health, and fertility in women with APECED. 2024.

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Cardiometabolic health and morbidity in offspring of women with type 1 diabetes

Cedric Korpijaakko: The findings from this thesis suggest that exposure to type 1 diabetes during fetal development might affect long-term health in offspring.

Cedric Korpijaakko: Cardiometabolic health and morbidity in offspring of women with type 1 diabetes

It has been suggested that exposure to maternal diabetes in utero may program the development of cardiometabolic diseases in offspring during adulthood.

The aim of this doctoral thesis was to assess whether maternal type 1 diabetes affects cardiometabolic health in offspring, by investigating prescription drug purchases and by evaluating clinical signs of cardiometabolic diseases during young adulthood.

From the age of seven, we observed that offspring of women with type 1 diabetes purchased significantly more prescription drugs for several indications than offspring of women without diabetes, with increased purchases of prescription drugs used in the treatment of diabetes and cardiovascular disease.

We could not find any differences between offspring of women with type 1 diabetes and offspring of women without diabetes for anthropometric measures or glucose or lipid concentrations in young adulthood.

A new finding was increased arterial stiffness in young adult offspring of women with type 1 diabetes compared to offspring of women without diabetes, while other metrics of cardiovascular disease remained similar.

The findings from this thesis suggest that exposure to type 1 diabetes during fetal development might affect long-term health in offspring.

Cedric Korpijaakko: Cardiometabolic health and morbidity in offspring of women with type 1 diabetes. 2024.