Genetic epidemiology of Greenland

The prevalence and disease course of autoimmune liver diseases in Greenland

Autoimmune liver diseases are rare serious diseases causing chronic inflammation and fibrosis in the liver parenchyma and bile ducts. Yet, the prevalence and burden of autoimmune liver diseases are largely unexplored in Arctic native populations. We investigated the prevalence and management of autoimmune liver diseases in Greenland using nationwide cross-sectional register data and subsequent medical chart reviews validating diagnoses and extracting liver histology examinations and medical treatments. The overall prevalence of autoimmune liver diseases in Greenland was 24.6 per 100,000 (95% CI: 14.7-41.3). This was based on 7 patients with autoimmune hepatitis (AIH) (12.3 per 100,000), 3 patients with primary biliary cholangitis (PBC) (5.3 per 100,000), 4 patients with AIH/PBC overlap disease (7.0 per 100,000), and no patients with primary sclerosing cholangitis. All diagnoses were confirmed by liver histology examinations. Medical treatments adhered to internal recommendations and induced complete remission in most patients with AIH, and complete or partial remission in 1 patient with PBC and 3 patients with AIH/PBC overlap disease. One patient had established cirrhosis at the time of diagnosis, while 2 patients progressed to cirrhosis. In conclusion, the prevalence of autoimmune liver diseases was lower in Greenland than in Scandinavia and among Alaska Inuit.

Skin diseases among adults in Tasiilaq, East Greenland

Cold climate and unique genetic and environmental factors may influence the prevalence of skin diseases in Greenland. However, there is a lack of epidemiological studies on skin diseases in the adult Greenlandic population. To address this unmet need a cross-sectional study, run by dermatologists from Denmark, the UK, and Switzerland estimated the prevalence and clinical manifestations of skin diseases among adults in East Greenland in May 2022. All adults ≥18 years in the town of Tasiilaq were invited, and 295 individuals aged 18-78 years participated (22.5% of the overall adult population in Tasiilaq). Two-hundred and three participants (69%) had visible signs of current skin disease, and among these, 242 cases of dermatoses were identified. The most common skin diseases were hand eczema (22.4%), lichen simplex (9.5%), discoid eczema (7.1%), psoriasis, atopic dermatitis and acne vulgaris (5.8% each). Scabies was the most frequent infectious skin disease (4.4%). No cases of skin cancer were identified. Atopic dermatitis and psoriasis presented with disease that was of limited extent and different from the classical presentations. Skin diseases showed a high prevalence among adults in East Greenland, and some of them were severe. This indicates a noteworthy public health problem that warrants better access to dermatologist support.

Burden of selected chronic non-communicable diseases in a primary healthcare setting in Nuuk, Greenland, compared to a Danish suburb

INTRODUCTION

Noncommunicable diseases (NCDs) constitute a massive global burden and are the leading cause of death and disability worldwide. In Greenland, the prevalence of NCDs has historically been low. However, during the past approximately 70 years, life circumstances have changed dramatically resulting in increased life expectancy. Today, the proportion of inhabitants in Greenland ≥65 years has nearly tripled since the 1980s, and the prevalence of obesity and diabetes has increased rapidly within the past decades. The aim of this study was to describe the burden of selected NCDs in a primary care setting in Nuuk and compare it to a modern westernized suburban general practice in Denmark.

METHODS

The study was performed as a cross sectional register-based study using data extracted from the electronic medical records (EMR) based on diagnosis codes from inhabitants living in Nuuk, Greenland, and a suburb in Denmark. Estimates of prevalence were age-standardized to the WHO world standard population.

RESULTS

In both Nuuk and the Danish suburb, the highest prevalence was observed for hypertension (13.2% for both populations), followed by asthma (4.4 and 9.5%, respectively) and diabetes (4.3 and 2.9%, respectively). The age-standardized prevalences of diabetes, COPD, atrial fibrillation, and heart failure, were significantly higher in Nuuk, while seven NCDs including asthma, ischemic heart disease, arthritis urica, psoriasis, hyperthyreosis, hypothyreosis and osteoporosis were significantly higher in the Danish suburb.

CONCLUSION

In contrast to the disease pattern observed in Greenland in the last century, the prevalence of diagnosed NCDs in Nuuk is no longer rare. Thus, the overall prevalence of NCDs in the population of Nuuk is now comparable to or even higher than in the suburb in Denmark. This calls for increased focus on all NCDs in the primary healthcare system in Greenland and adaption of the primary healthcare services to a changed disease spectrum.

The Prevalence of Inflammatory Bowel Disease in Greenland

BACKGROUND

Inflammatory bowel disease (IBD) is sparsely investigated in Arctic populations. The aim of this study was to estimate the prevalence of ulcerative colitis (UC) and Crohn's disease (CD) in Greenland.

METHODS

Cross-sectional nationwide data on demography, anthropometry, biochemistry, and pharmacotherapy were extracted from the electronic medical records in Greenland. Diagnoses of UC and CD were based on International Classification of Diseases-Tenth Revision and International Classification of Primary Care-Second Edition coding and treatment with mesalazine. Data from Statistics Greenland were used for prevalence calculations.

RESULTS

In total, 254 patients in Greenland experienced IBD, with 214 cases of UC and 40 cases of CD. The overall IBD prevalence was 0.45%, distributed as 0.38% with UC and 0.07% with CD. The IBD prevalence was similar across the 5 regions of Greenland. However, a higher prevalence was observed in the region main towns with the largest populations (0.53%) compared with the small towns along the coastline (0.29%). UC patients were prescribed mesalazine treatment with a frequency of 78%. Furthermore, 10% of all IBD patients received treatment with nonspecific immunomodulators and 7% received biologics.

CONCLUSIONS

This study estimates the prevalence and uncovers characteristics of IBD in Greenland. Although CD may be underdiagnosed or less prevalent, the overall prevalence of IBD in Greenland parallels Scandinavian countries and North America. These results boost the knowledge on autoimmune diseases in arctic populations and may guide clinicians in their management of IBD in Greenland. Furthermore, the results may encourage research in IBD across the Arctic regions.

Low prevalence of patients diagnosed with psoriasis in Nuuk: a call for increased awareness of chronic skin disease in Greenland

The objective of this study was to estimate the age- and gender-specific prevalence of psoriasis in Nuuk. Furthermore, we aimed to explore the common risk factors and comorbidities for patients with psoriasis compared to an age- and gender-matched control group. The study was designed as a cross- sectional case-control study based on national high-quality data from medical and population registers in Nuuk. A total of 175 patients (0.9%) were diagnosed with psoriasis in Nuuk by January 1 January 2022, of which 79 were females and 96 were males. The prevalence of patients diagnosed with psoriasis in the adult population aged 20 years old or more in Nuuk was 1.1%. No overall gender-specific difference in prevalence was observed. Chronic diseases including diabetes, hypertension, and obstructive lung disease were observed more frequently among patients with diagnosed psoriasis (28.6%) in Nuuk compared to controls (20.9%) (p < 0.05). We found a low prevalence of patients with psoriasis in Nuuk. We speculate that the prevalence found in this study is underestimated and thus, call for increased awareness of chronic skin disease in Nuuk, Greenland. Chronic co-morbidity to psoriasis was common.

Dioxin-like Activity in Pregnant Women and Indices of Fetal Growth: The ACCEPT Birth Cohort

Exposure to lipophilic persistent organic pollutants (lipPOPs) elicits a number of species- and tissue-specific toxic responses, many of which involve the aryl hydrocarbon receptor (AhR). This study aims to measure the combined serum dioxin-like activity of lipPOPs in Greenlandic Inuit pregnant women and the associations with fetal growth indices. The combined dioxin-like activity of serum lipPOPs extracts was determined using the AhR reporter gene bioassay and expressed as pico-gram (pg) TCDD equivalent (TEQ) per gram serum lipid [AhR-TEQ (pg/g lipid)]. Significant AhR-TEQ was found in >87% of serum samples with the median level of 86.2 pg TEQ/g lipid. The AhR-TEQ level positively correlated with the marine food intake biomarker n-3/n-6 polyunsaturated fatty acids ratio, while negatively correlated with body mass index and parity. Women giving birth to infants with low birth weight (<2500 g) and length (<50 cm) had higher AhR-TEQ level compared to those with normal weight and length infants. For previous smokers, we found significant inverse associations between maternal AhR-TEQ level and fetal growth indices. In conclusion, exposure of Greenlandic Inuit pregnant women to dioxin-like compounds through traditional marine food can adversely influence the fetal growth via induced AhR activity. Smoking might have modifying effects.

Non-infectious skin disease in Indigenous Australians

The burden of non-infectious skin disease in the Indigenous Australian population has not been previously examined. This study considers the published data on the epidemiology and clinical features of a number of non-infectious skin diseases in Indigenous Australians. It also outlines hypotheses for the possible differences in the prevalence of such diseases in this group compared with the general Australian population. There is a paucity of literature on the topic but, from the material available, Indigenous Australians appear to have a reduced prevalence of psoriasis, type 1 hypersensitivity reactions and skin cancer but increased rates of lupus erythematosus, kava dermopathy and vitamin D deficiency when compared to the non-Indigenous Australian population. This article profiles the prevalence and presentation of non-infectious skin diseases in the Indigenous Australian population to synthesise our limited knowledge and highlight deficiencies in our understanding.

Psoriasis and streptococci: the natural selection of psoriasis revisited

We have previously postulated that surviving invasive streptococcal infections may have been a factor in psoriasis becoming a common skin disease in some parts of the world. Many of the candidate genes linked to psoriasis are associated with the acquired or innate immune system, which are also important in host defence to invasive streptococcal infections. High rates of positive streptococcal throat swabs among patients with chronic plaque psoriasis suggest that they are efficient at internalizing/carrying beta-haemolytic streptococci. Internalization of streptococci in the throat is dependent upon the transforming growth factor (TGF)-beta/fibronectin/alpha 5 beta 1 integrin pathway. The immune cell Th17 and its related cytokine network are important in mucosal defence, being very effective against extracellular microbes but having little effect on intracellular organisms. The TGF-beta/fibronectin/alpha 5 beta 1 integrin pathway and the Th17 cell network also appear to be operative in psoriasis, animal models of both TGF-beta and alpha 5 beta 1 cutaneous overexpression being associated with characteristic psoriasis lesions. We postulate that some of the genotypic/phenotypic changes in different immunological pathways in psoriasis, including the acquired T-cell response, the innate immune response, the TGF-beta/fibronectin/alpha 5 beta 1 integrin pathway and the Th17 cell system, confer protection against mortality during epidemics of invasive streptococcal infections, heightened efficiency in internalizing and allowing carriage of streptococci as well as predisposition to the development of psoriasis.

Cancer patterns in Inuit populations

Inuit people inhabit the circumpolar region, with most living in Alaska, northwest Canada, and Greenland. Although malignant diseases were believed to be almost non-existent in Inuit populations during the beginning of the 20th century, the increasing life expectancy within these populations showed a distinct pattern, characterised by a high risk of Epstein-Barr virus-associated carcinomas of the nasopharynx and salivary glands, and a low risk of tumours common in white populations, including cancer of the prostate, testis, and haemopoietic system. Both genetic and environmental factors seem to be responsible for this pattern. During the second half of the 20th century, Inuit societies underwent major changes in lifestyle and living conditions, and the risk of lifestyle-associated tumours, especially cancers of the lung, colon, and breast, increased considerably after changes in smoking, diet, and reproductive factors. This Review will briefly summarise the current knowledge on cancer epidemiology in Inuit populations, with emphasis on the characteristic Inuit types of cancer.

Psoriasis, innate immunity, and gene pools

Recently, emphasis has shifted from T cells to innate (natural) immunity as the possible major culprit in psoriasis. All known elements of innate immune responses are up-regulated in psoriasis lesions, which must have a polygenetic origin. We hypothesize that urbanized populations have been under evolutionary pressure that selects for increased innate immunity responses because those offer relative but immediate protection from epidemic infections. That would have resulted in a changing gene pool, in which alleles of polymorphisms associated with increased innate immunity responses have amplified in these populations. Having too many of these genes together in one individual would result in a relatively low number of infections. On the other hand, it would also result in a higher prevalence of diseases related to increased innate immunity, such as psoriasis, and perhaps also multiple sclerosis and rheumatoid arthritis. Indeed, in indigenous people (Inuit, Aborigines, Ami) who have not been under this selection pressure, morbidity due to infections is high and the prevalence of psoriasis is low or even absent.

Pattern of hypocretin (orexin) soma and axon loss, and gliosis, in human narcolepsy

Human narcolepsy is correlated with a greatly reduced number of hypocretin (orexin) containing neurons and axons, and an elevated level of hypothalamic gliosis. We now report that the percentage loss of Hcrt cells and percentage elevation of GFAP staining are variable across forebrain and brain-stem nuclei, and are maximal in the posterior and tuberomammillary hypothalamic region. Regional gliosis and percent loss of hypocretin axons in narcoleptics are not correlated with regional hypocretin cell soma density in normals or with regional percent soma loss in narcoleptics. Rather they are independently and strongly correlated with the regional density of hypocretin axons and the message density for hypocretin receptor 2, as quantified in the rat. These results are consistent with the hypotheses that the loss of hypocretin function in narcolepsy results from a cytotoxic or immunologically mediated attack focused on hypocretin receptor 2 or an antigen anatomically linked to hypocretin receptor 2, and that this process is intensified in regions of high axonal density.

Cancer immunotherapy: insights from transgenic animal models

A wide range of strategies in cancer immunotherapy has been developed in the last decade, some of which are currently being used in clinical settings. The development of these immunotherapeutical strategies has been facilitated by the generation of relevant transgenic animal models. Since the different strategies in experimental immunotherapy of cancer each aim to activate different immune system components, a variety of transgenic animals have been generated either expressing tumor associated, HLA, oncogenic or immune effector cell molecule proteins. This review aims to discuss the existing transgenic mouse models generated to study and develop cancer immunotherapy strategies and the variable results obtained. The potential of the various transgenic animal models regarding the development of anti-cancer immunotherapeutical strategies is evaluated.

A unique pattern of apo(a) polymorphism in an isolated east Greenlandic Inuit (Eskimo) population

Eskimos of the east coast of Greenland very rarely had contacts with Caucasians until late in the 19th century. Their genes are therefore likely to be similar to those in the original Eskimo gene pool. We have compared serum concentrations of Lp(a) and apo(a) phenotypes in 78 East Greenland Eskimos (EGE) with those in Eskimos from Western Greenland (WGE) (n = 100) and Caucasian Danes (n = 466). Lp(a) levels were higher in EGE (median: 11.9 mg/dl [95% CI: 9.1-16.4]) than in Danes (p < 0.01), (median: 6.3 mg/dl [95% CI: 5.5-7.3]) and WGE (p < 0.01), (median: 7.8 mg/dl [95% CI: 5.7-10.2]). Lp(a) concentrations above 30 mg/dl were (p < 0.05) more common in EGE (19%) than in WGE (9%) and similar (p = 0.89) to those in Danes (20%). Apo(a) molecules as small as S2 or smaller (S1, B and F) were present in 26% of Danes and in 3% of WGE but were absent in EGE (p < 0.01). In contrast, a large apo(a) variant (VS4) was present in 54% of EGE and 62% of WGE, whereas it was very rare in Danes (2%). Lp(a) concentrations were inversely associated with apo(a) size in EGE (p < 0.05), WGE (p < 0.01) and Danes (p < 0.01), but EGE with S3 or S4 had significantly higher Lp(a) levels than Danes (p < 0.05) with the same phenotypes.