High incidence of amyotrophic lateral sclerosis in the Faroe Islands 2010-2020

Islands and Neurology: An Exploration into a Unique Association

The current study investigates the intricate connection between neurology and islands shedding light on the historical, epidemiological, and genetic aspects. Based on an elaborate literature review, we identified neurological conditions having a significant clustering in an island(s), confined to a particular island(s), named after an island, and described first in an island. The genetic factors played a crucial role, uncovering disorders like Cayman ataxia, Machado Joseph disease, SGCE-mediated dystonia-myoclonus syndrome, X-linked dystonia parkinsonism, hereditary transthyretinrelated amyloidosis, Charcot Marie Tooth 4F, and progressive myoclonic epilepsy syndromes, that exhibited remarkable clustering in diverse islands. Local customs also left enduring imprints. Practices such as cannibalism in Papua New Guinea led to Kuru, while cycad seed consumption in Guam triggered Lytico-Bodig disease. Toxin-mediated neurologic disorders exhibited intricate island connections, exemplified by Minamata disease in Kyushu islands and atypical parkinsonism in French Caribbean islands. Additionally, the Cuban epidemic of amblyopia and neuropathy was associated with severe nutritional deficiencies. This study pioneers a comprehensive review narrating the genetic, environmental, and cultural factors highlighting the spectrum of neurological disorders in island settings. It enriches the medical literature with a unique understanding of the diverse influences shaping neurological health in island environments.

Increased incidence of motor neuron disease in Sweden: a population-based study during 2002-2021

BACKGROUND

Motor neuron diseases (MND), with amyotrophic lateral sclerosis constituting most cases, are rare conditions of unknown etiology. There have been reports of an increase in incidence during the latter half of the twentieth century in various Western countries, including Sweden. This study provides updated data on the incidence of MND in Sweden during the last 20 years.

METHODS

Data was obtained from the Swedish National Patient Register on individuals diagnosed with MND from 2002 to 2021 and analysed in relation to group level data for the entire Swedish population. Incidence rates were calculated and presented in relation to year, age, sex, and region.

RESULTS

In the early 2000s, there was a crude incidence rate of 3.5-3.7 per 100,000 person-years, which then increased to 4.0-4.6 from 2008 onward. Age standardization to the starting year (2002) partially mitigated this increase. The incidence rate was greater among men compared to women and was highest within the age range of 70 to 84 years. There were indications of a higher incidence rate in the northernmost parts of the country, although the difference was not statistically significant.

CONCLUSIONS

The incidence rate of MND in Sweden now seems to have surpassed 4 cases per 100,000 person-years. This is higher when compared to both other European countries and previous Swedish studies. It remains to be determined if this increase reflects an actual increasing incidence of MND in Sweden or is due to other factors such as better registry coverage.

Possible explanations for the common clinical familial hypercholesterolemia phenotypes in the Faroe Islands

BACKGROUND

The prevalence of clinical familial hypercholesterolemia (FH) is very high in the Faroe Islands, but the possible causes are unknown.

OBJECTIVES

We aimed to describe potential genetic causes of FH in the Faroe Islands and to investigate whether levels of lipoprotein(a) and measures of dietary habits were associated with clinical FH in the Faroe Islands.

METHODS

In this case-control study, we identified potential clinical FH cases aged 18-75 years registered within a nationwide clinical laboratory database in the Faroe Islands and invited them for diagnostic evaluation according to clinical FH scoring systems. Controls were identified in the background population. Lipoprotein(a) was measured in plasma, while the fatty acid composition was determined in adipose tissue. The habitual diet of the participants was assessed using a food frequency questionnaire. Genetic testing for FH and polygenic variants was performed in a selection of clinical FH cases.

RESULTS

A total of 121 clinical FH cases and 123 age- and sex-matched controls were recruited. We found a very low frequency of monogenic FH (2.5%), but a high level of polygenic FH (63%) in those genetically tested (67%). High levels of plasma lipoprotein(a) were associated with high odds of clinical FH. Clinical FH cases had a lower intake of saturated fatty acids (SFAs) measured by a high fat-score and a lower content of SFAs in adipose tissue compared with controls.

CONCLUSION

The high prevalence of FH in the Faroe Islands may be due to polygenic causes of hypercholesterolemia and to a lesser extent other genetic factors and elevated plasma lipoprotein(a) levels.

Cancer survival in the Faroe Islands over the last 50 years compared to the other Nordic countries

As sustained development in cancer treatment protocols have led to improved survival in most areas of the world, surveillance is needed to ensure that small populations follow suit. Our study reports age-standardized relative cancer survival in the Faroe Islands compared to the other Nordic countries. We present 1- and 5-year survival estimates and corresponding 95% confidence intervals for the Faroe Islands and compare them with estimates for the Nordic countries. The data for this article has been obtained through the NORDCAN collaboration (2019 data). Age-standardized relative survival was estimated using shared R codes on individual-level data within each country. Ten-year calendar inclusion periods were used in addition to the usual 5-year calendar periods to include cancer sites with few cases, which is especially beneficial to the smaller populations. The primary findings were that 1- and 5-year survival were consistently lower in the Faroes for the summary group all sites but non-melanoma skin cancer for both women and men. Further, 5-year survival was lower for women with ovarian cancer and men with lung cancer than in other Nordic countries. Previously, breast cancer survival was low in the Faroes but has improved to a comparable level over the last few years. Colorectal cancer survival was relatively high for both sexes. The reported estimates in this article call for further research to investigate the cancers with lower survival and should call for actions to improve the survival of Faroese cancer patients.

Early-onset, conjugal, twin-discordant, and clusters of sporadic ALS: Pathway to discovery of etiology via lifetime exposome research

The identity and role of environmental factors in the etiology of sporadic amyotrophic lateral sclerosis (sALS) is poorly understood outside of three former high-incidence foci of Western Pacific ALS and a hotspot of sALS in the French Alps. In both instances, there is a strong association with exposure to DNA-damaging (genotoxic) chemicals years or decades prior to clinical onset of motor neuron disease. In light of this recent understanding, we discuss published geographic clusters of ALS, conjugal cases, single-affected twins, and young-onset cases in relation to their demographic, geographic and environmental associations but also whether, in theory, there was the possibility of exposure to genotoxic chemicals of natural or synthetic origin. Special opportunities to test for such exposures in sALS exist in southeast France, northwest Italy, Finland, the U.S. East North Central States, and in the U.S. Air Force and Space Force. Given the degree and timing of exposure to an environmental trigger of ALS may be related to the age at which the disease is expressed, research should focus on the lifetime exposome (from conception to clinical onset) of young sALS cases. Multidisciplinary research of this type may lead to the identification of ALS causation, mechanism, and primary prevention, as well as to early detection of impending ALS and pre-clinical treatment to slow development of this fatal neurological disease.

The challenge of amyotrophic lateral sclerosis descriptive epidemiology: to estimate low incidence rates across complex phenotypes in different geographic areas

PURPOSE OF REVIEW

Amyotrophic lateral sclerosis (ALS) is a rare progressive neurodegenerative disease of motor neurons with a fatal outcome. The rareness of the disease and the rapidly fatal course are the main challenges for the ALS epidemiological research. The understanding of ALS has clearly advanced in the recent years both in the genetics and in the leading pathways of disease determinants. Epidemiological research has played a primary role in these discoveries.

RECENT FINDINGS

Epidemiological studies have shown a variation of incidence, mortality and prevalence of ALS between geographical areas and different populations, supporting the notion that genetic factors, linked to populations' ancestries, along with environmental and lifestyle factors, play a significant role in the occurrence of the disease. The burden of motor neuron diseases is increasing and currently more relevant in high-income countries but increasing at the highest rate in low and middle-income countries. The ALS phenotype is not restricted to motor functions. C9orf72 repeat expansion seems to present a recognizable phenotype characterized by earlier disease onset, the presence of cognitive and behavioural impairment.

SUMMARY

Population-based disease registries have played a major role in developing new knowledge on ALS, in characterizing genotype-phenotype correlations, in discovering new genetic modifiers and finally in planning research and health services, considering the high cost of motor neuron disease care. Epidemiological research based on multicentre international collaboration is essential to provide new data on ALS, especially in some regions of the world with poor data.

Cancer in the Faroe Islands from 1960-2019 - incidence, mortality, and comparisons with the other Nordic countries

Purpose: In this paper, we present age-standardized cancer incidence and mortality rates in the Faroe Islands. We also compare with the Nordic rates and show incidence rate ratios (IRR) and mortality rate ratios (MRR).Materials and methods: The Faroese cancer registry (FCR) was established in 1994, with incidence available from 1960 and mortality from 1983. The FCR is a part of the NORDCAN collaboration, where the different Nordic countries all report anonymized cancer data by standardized methods, ensuring comparability. Validation efforts revealed that 13% of cases had not been reported to the FCR from 2006 to 2019, emphasizing the need for continued validation efforts of cancer registries. After validation, we submitted the updated cancer cases to NORDCAN and now present this data, taken directly from the NORDCAN website (2019 data).Results: We found that the incidence of the summary group all cancers in the Faroe Islands increased from 1960 to 2019, while cancer mortality decreased from 1983 to 2019. Comparisons with Nordic rates showed significantly lower IRRs for cancer in all cancers, bladder and urinary tract, and skin cancer for both sexes, while IRR was lower for breast cancer in women and prostate cancer in men. Contrary, IRR was higher for rectum and kidney cancer in women and esophagus and testicular cancer in men. There was an increased MRR for cancer in female organs, bladder and urinary tract, and kidney cancer in women, and esophagus and pancreas cancer in men. In contrast, malignant hematopoietic diseases and melanoma in women had a lower MRR.Conclusions: Cancer incidence in the Faroe Islands was lower than in the other Nordic countries. Of particular interest, the incidence of testicular cancer saw a steep increase during the last 20 years, and an investigation into possible causes for this is needed.