Publications

Ca homoeostasis is important to human health and tightly controlled by powerful hormonal mechanisms that display ethnic variation. Ethnic variations could occur also in Arctic populations where the traditional Inuit diet is low in Ca and sun exposure is limited. We aimed to assess factors important to parathyroid hormone (PTH) and Ca in serum in Arctic populations. We included Inuit and Caucasians aged 50–69 years living in the capital city in West or in rural East Greenland. Lifestyle factors were assessed by questionnaires. The intake of Inuit diet was assessed from a FFQ. 25-Hydroxyvitamin D (25OHD2 and 25OHD3) levels were measured in serum as was albumin, Ca and PTH. The participation rate was 95 %, with 101 Caucasians and 434 Inuit. Median serum 25OHD (99·7 % was 25OHD3) in Caucasians/Inuit was 42/64 nmol/l (25, 75 percentiles 25, 54/51, 81) (P<0·001). Total Ca in serum was 2·33/2·29 mmol/l (25, 75 percentiles 2·26, 2·38/2·21, 2·36) (P=0·01) and PTH was 2·7/2·2 pmol/l (25, 75 percentiles 2·2, 4·1/1·7, 2·7) (P<0·001). The 69/97 Caucasians/Inuit with serum 25OHD <50 nmol/l differed in PTH (P=0·001) that rose with lower 25OHD levels in Caucasians, whereas this was not the case in Inuit. Ethnic origin influenced PTH (β=0·27, P<0·001) and Ca (β=0·22, P<0·001) in multivariate linear regression models after adjustment for age, sex, BMI, smoking, alcohol and diet. In conclusion, ethnic origin influenced PTH, PTH response to low vitamin D levels and Ca levels in populations in Greenland. Recommendations are to evaluate mechanisms underlying the ethnic influence on Ca homoeostasis and to assess the impact of transition in dietary habits on Ca homoeostasis and skeletal health in Arctic populations.

We previously showed that a common genetic variant leads to a remarkably increased risk of type 2 diabetes (T2D) in the small and historically isolated Greenlandic population. Motivated by this, we aimed at discovering novel genetic determinants for glycated hemoglobin (HbA1C) and at estimating the effect of known HbA1C-associated loci in the Greenlandic population. We analyzed genotype data from 4049 Greenlanders generated using the Illumina Cardio-Metabochip. We performed the discovery association analysis by an additive linear mixed model. To estimate the effect of known HbA1C-associated loci, we modeled the effect in the European and Inuit ancestry proportions of the Greenlandic genome (EAPGG and IAPGG, respectively). After correcting for multiple testing, we found no novel significant associations. When we investigated loci known to associate with HbA1C levels, we found that the lead variant in the GCK locus associated significantly with HbA1C levels in the IAPGG (PIAPGG=4.8×10−6,βIAPGG=0.13SD). Furthermore, for 10 of 15 known HbA1C loci, the effects in IAPGG were similar to the previously reported effects. Interestingly, the ANK1 locus showed a statistically significant ancestral population differential effect, with opposing directions of effect in the two ancestral populations. In conclusion, we found only 1 of the 15 known HbA1C loci to be significantly associated with HbA1C levels in the IAPGG and that two-thirds of the loci showed similar effects in Inuit as previously found in European and East Asian populations. Our results shed light on the genetic effects across ethnicities.

The purpose of the article is to compare different indicators of social position as measures of social inequality in health in a population sample from an indigenous arctic people, the Inuit in Greenland. Data was collected during 2005–2015 and consisted of information from 3967 adult Inuit from towns and villages in all parts of Greenland. Social inequalities for smoking and central obesity were analysed in relation to seven indicators of social disparity in four dimensions, i.e. education and employment, economic status, sociocultural position, and place of residence. For each indicator we calculated age-adjusted prevalence by social group, rate ratio and the concentration index. The indicators were correlated with Pearson’s r ranging from 0.24 to 0.82. Concentration indices ranged from 0.01 to 0.17. We could not conclude that one indicator was superior to others. Most of the indicators were traditional socioeconomic indicators used extensively in research in western countries and these seemed to be useful among the Inuit too, in particular household assets and job. Two sociocultural indicators developed for use among the Inuit and which included parameters specific to the indigenous peoples in the transition from a traditional to a modern life style proved to be equally useful but not superior to the traditional socioeconomic indicators. The choice of indicator must depend on what it is realistic to collect in the actual research setting and the use of more than one indicator is recommended. It is suggested to further develop culture specific indicators of social position for indigenous peoples.

Greenland is a country in transition from a colonial past with subsistence hunting and fishing to an urban Nordic welfare state. Epidemiological transition from infectious to chronic diseases has been evident since the 1950s. Ninety percent of the population is Inuit.

We studied three public health issues based on published literature, namely adverse childhood experiences, addictive behavior, and suicide; diet and obesity; and smoking. Alcohol consumption was high in the 1970s and 1980s with accompanying family and social disruption. This is still a cause of poor mental health and suicides in the generations most affected. The diet is changing from a traditional diet of fish and marine mammals to imported food including food items rich in sugar and fat from domestic animals, and the level of physical activity is decreasing with an ensuing epidemic rise in obesity. The prevalence of smoking is high at around 60% among both men and women and is only slowly decreasing. Smoking shows large social variation, and tobacco-related diseases are widespread.

The diseases and conditions outlined above all contribute towards a low life expectancy at birth—69 years for men and 74 years for women in 2011–2015—compared with 78 and 84 years for men and women, respectively, on average in the European countries. The translation of government public health programs into local activities needs strengthening, and it must be realized that the improvement of public health is a long-term process.

Background and aims: Low levels of vitamin D are suspected to be a risk factor for cardiovascular disease and atherosclerosis. The aim of this study was to assess the prevalence of subclinical atherosclerosis among Inuit in Greenland, and to evaluate the association with vitamin D status. We hypothesized that low vitamin D status could be associated with higher carotid intima-media thickness (IMT) as a marker of atherosclerosis.

Methods: 756 adults from the Inuit Health in Transition (IHIT) study carried out in Greenland in the period 2005–2010 were included. A blood sample donated in 1987 was available for a sub-sample of 102 individuals. Serum 25(OH)D3 from the IHIT study and the 1987 survey was used as a measure of vitamin D status. IMT measurements were conducted by ultrasound scanning. The prevalence of atherosclerosis was estimated, and the association between serum 25(OH)D3 and IMT measurements was examined by linear regression.

Results: The overall prevalence of subclinical atherosclerosis was 20.1% (n = 152). The linear regression analyses indicated a weak positive association between serum 25(OH)D3 level and IMT measurements from the IHIT study, though not statistically significant after adjustment for potential confounders (β = 0.35% per 10 nmoL/L 25(OH)D3, p = 0.06). Linear regression analyses of the association between serum 25(OH)D3 level in the 1987 survey and IMT measurements also indicated a positive, though not statistically significant, association after adjustment (β = 0.07% per 10 nmoL/L 25(OH)D3, p = 0.86).

Conclusions: Our findings did not support the hypothesis of an association between low vitamin D levels and risk of atherosclerosis.