Decrease in vitamin D status in the Greenlandic adult population from 1987-2010

Determining the vitamin D supplementation duration to reach an adequate or optimal vitamin D status and its effect on blood lipid profiles: a longitudinal study

BACKGROUND

Recently, Serum vitamin D (Vit. D) levels evaluation and the use of Vit. D supplements have increased substantially. There is no specific guideline for the duration of Vit. D supplementation, so yet Vit. D supplementation duration has remained a critical and controversial issue. This study aimed to determine the vit. D supplementation duration to reach an adequate or optimal Vit. D status and its effect on lipid profile.

METHODS

In this longitudinal study, 345 women with different status of Vit. D levels were enrolled and followed up for one year. Eligible participants received 50,000 IU Vit. D3 (cholecalciferol) once a month for 12 consecutive months. The serum Vit. D levels and lipid profiles were measured at baseline, 3rd, 6th, and 12th months after the intervention. Participants were categorized based on Vit. D level at baseline into deficiency (< 20 ng/mL), inadequate (20-30 ng/mL), and adequate (> 30 ng/mL) groups, and the data were compared at different times between the three groups.

RESULTS

Three deficiency (n = 73), inadequate (n = 138) and adequate (n = 134) groups of participants were followed. In all participants the average amount of Vit. D level changes were 8 ng/mL after one year of supplementation. The mean changes of serum Vit. D level in 6th and 12th months vs. 3th month was as below: In deficiency group: 4.08 ± 0.85 and 10.01 ± 1.02 ng/mL; (p < 0.001), in inadequate group: 3.07 ± 0.59 and 7.26 ± 0.78 ng/mL; (p = 0.001) and in adequate group: 2.02 ± 0.88 and 6.44 ± 1.005 ng/ml; (p = 0.001). Lipid profiles were improved in three groups. So, the mean changes of lipid profiles at the end of the study comparing with the baseline were: -5.86 ± 2.09, -7.22 ± 1.43 and - 6.17 ± 1.72 (mg/dl) for LDL (p < 0.05); -12.24 ± 3.08, -13.64 ± 3.21 and - 17.81 ± 2.94 (mg/dl) for cholesterol (p < 0.05) in deficiency, inadequate and adequate groups, respectively. For triglyceride, the mean changes were - 13.24 ± 5.78 and - 15.85 ± 7.49 (mg/dl) in deficiency and adequate groups, respectively (p < 0.05). Although the triglyceride decreased in the inadequate group at the end of the study but this difference was not significant (p = 0.67).

CONCLUSION

Taking of 50,000 IU Vit. D 3 monthly for 12 months resulted in reaching its level to adequate level in both deficiency and insufficient groups; however, in the adequate group its level did not reach above than 50 ng/mL. Therefore, 50,000 IU Vit. D3 supplementation monthly for one year can have beneficial effects on lipid profiles and there is no risk of toxicity in healthy women.

Wild fish consumption and latitude as drivers of vitamin D status among Inuit living in Nunavik, northern Québec

OBJECTIVE

To measure vitamin D status and estimate factors associated with serum 25-hydroxyvitamin D (25(OH)D) in Nunavimmiut (Inuit living in Nunavik) adults in 2017.

DESIGN

Data were from Qanuilirpitaa? 2017 Nunavik Inuit Health Survey, a cross-sectional study conducted in August-October 2017. Participants underwent a questionnaire, including an FFQ, and blood samples were analysed for total serum 25(OH)D.

SETTING

Nunavik, northern Québec, Canada.

PARTICIPANTS

A stratified proportional model was used to select respondents, including 1,155 who identified as Inuit and had complete data.

RESULTS

Geometric mean serum vitamin D levels were 65·2 nmol/l (95 % CI 62·9-67·6 nmol/l) among women and 65·4 nmol/l (95 % CI 62·3-68·7 nmol/l) among men. The weighted prevalence of serum 25(OH)D < 75 nmol/l, <50 nmol/l <30 nmol/l was 61·2 %, 30·3 % and 7·0 %, respectively. Individuals who were older, female, lived in smaller and/or more southerly communities and/or consumed more country (traditional) foods were at a reduced risk of low vitamin D status. Higher consumption of wild fish was specifically associated with increased serum 25(OH)D concentration.

CONCLUSION

It is important that national, regional and local policies and programs are in place to secure harvest, sharing and consumption of nutritious and culturally important country foods like Arctic char and other wild fish species, particularly considering ongoing climate change in the Arctic which impacts the availability, access and quality of fish as food.

Low vitamin D levels among children and adolescents in an Arctic population

AIMS

We aimed to study the vitamin D status of the population of Arkhangelsk, a city in northwestern Russia.

METHODS

A cross-sectional study was conducted to estimate serum 25(OH)D concentrations in Arkhangelsk residents, including 55 neonates and their mothers, 214 children <3 years, 191 schoolchildren (7-8 years), 403 adolescents (13-17 years), 260 university students (18-22 years) and 85 adults (24-60 years). The data were collected from March 2013 to November 2014 and from January 2016 to May 2016.

RESULTS

Normal levels of 25(OH)D (>30 ng/ml) were found in 5% of neonates, 43% of their mothers, 43% of children <3 years, 9% of schoolchildren, 1% of adolescents, 17% of students and 26% of adults. There was a moderate positive correlation (rs = 0.563, p = 0.001) between 25(OH)D levels in mother's blood and umbilical cord blood.

CONCLUSIONS

Vitamin D deficiency is highly prevalent in the population of Arkhangelsk, particularly in neonates, schoolchildren and adolescents.

Vitamin D status of the Russian adult population from 2013 to 2018

Vitamin D deficiency is widespread globally, however available data for the Russian adult population is fragmented. This cross-sectional study used secondary data for individuals undergoing testing for vitamin D concentrations from 2013 to 2018 by InVitro laboratory. 25(OH)D serum concentration was determined using chemiluminescent microparticle immunoassay. The mean, median, and proportion with severe, deficient, insufficient and sufficient 25-hydroxyvitamin D (25(OH)D) concentrations were estimated. Splines examined the effect of latitude on 25(OH)D concentrations. Data were available for 30,040 subjects age ≥ 18 years. 24.2% of the sampled population had sufficient (30-< 150 25(OH)D ng/mL), 34% deficient (10-19.9 ng/mL) and 5.6% severely deficient (< 10 ng/mL) status. Average 25(OH)D concentrations were highest among 30-44 years and lowest amongst older adults; females had modestly higher values. Concentrations were 15% higher in fall/summer vs. winter/spring. A non-linear relationship was observed by latitude; the highest 25(OH)D concentrations were observed near 54°N, decreasing at more southern latitudes for women and more northern latitudes for both sexes. These results are comparable to other Northern European publications and limited Russian samples demonstrating low concentrations. Acknowledging that nationally-representative and randomly sampled data are needed, the present data suggest the burden may be high and identifies some population sub-groups and geographic areas with a higher potential deficiency of vitamin D.

The prevalence of patients treated for osteoporosis in Greenland is low compared to Denmark

The study is a register-based cross-sectional study aiming to estimate the prevalence of treated osteoporosis in Greenland compared to Denmark and provide a description of the patients with osteoporosis in Greenland. In addition, the study estimates the incidence of hip fractures in Greenland from 2018 to 2020 among people aged 65 years or older. The overall prevalence of patients prescribed medication for osteoporosis among those aged 18 years or older was 0.56% in Greenland and 2.36% in Denmark (p < 0.001). Among those aged 50 years or older, the prevalence was 1.28% and 4.71% in Greenland and Denmark, respectively (p < 0.001). The prevalence increased to 3.41% and 11.18% among patients aged 80 years or older in Greenland and Denmark, respectively. The incidence of hip fractures in Greenland was 6.55 per 1,000 inhabitants in 2020 compared to 5.65 per 1,000 inhabitants in Denmark (NS). In conclusion, the prevalence of treated osteoporosis in Greenland was less than one in four of that of Denmark. The incidence of hip fractures was similar in Greenland than in Denmark. Hence, our findings suggest that a marked number of subjects with osteoporosis in Greenland go untreated.

Decision models in type 2 diabetes mellitus: A systematic review

AIMS

To reduce the burden of type 2 diabetes (T2DM), the disease decision model plays a vital role in supporting decision-making. Currently, there is no comprehensive summary and assessment of the existing decision models for T2DM. The objective of this review is to provide an overview of the characteristics and capabilities of published decision models for T2DM. We also discuss which models are suitable for different study demands.

MATERIALS AND METHODS

Four databases (PubMed, Web of Science, Embase, and the Cochrane Library) were electronically searched for papers published from inception to August 2020. Search terms were: "Diabetes-Mellitus, Type 2", "cost-utility", "quality-of-life", and "decision model". Reference lists of the included studies were manually searched. Two reviewers independently screened the titles and abstracts following the inclusion and exclusion criteria. If there was insufficient information to include or exclude a study, then a full-text version was sought. The extracted information included basic information, study details, population characteristics, basic modeling methodologies, model structure, and data inputs for the included applications, model outcomes, model validation, and uncertainty.

RESULTS

Fourteen unique decision models for T2DM were identified. Markov chains and risk equations were utilized by four and three models, respectively. Three models utilized both. Except for the Archimedes model, all other models (n = 13) implemented an annual cycle length. The time horizon of most models was flexible. Fourteen models had differences in the division of health states. Ten models emphasized macrovascular and microvascular complications. Six models included adverse events. Majority of the models (n = 11) were patient-level simulation models. Eleven models simulated annual changes in risk factors (body mass index, glycemia, HbA1c, blood pressure (systolic and/or diastolic), and lipids (total cholesterol and/or high-density lipoprotein)). All models reported the main data sources used to develop health states of complications. Most models (n = 11) could deal with the uncertainty of models, which were described in varying levels of detail in the primary studies. Eleven studies reported that one or more validation checks were performed.

CONCLUSIONS

The existing decision models for T2DM are heterogeneous in terms of the level of detail in the classification of health states. Thus, more attention should be focused on balancing the desired level of complexity against the required level of transparency in the development of T2DM decision models.

Adaptation and co-adaptation of skin pigmentation and vitamin D genes in native Americans

We carried out an exhaustive review regarding human skin color variation and how much it may be related to vitamin D metabolism and other photosensitive molecules. We discuss evolutionary contexts that modulate this variability and hypotheses postulated to explain them; for example, a small amount of melanin in the skin facilitates vitamin D production, making it advantageous to have fair skin in an environment with little radiation incidence. In contrast, more melanin protects folate from degradation in an environment with a high incidence of radiation. Some Native American populations have a skin color at odds with what would be expected for the amount of radiation in the environment in which they live, a finding challenging the so-called "vitamin D-folate hypothesis." Since food is also a source of vitamin D, dietary habits should also be considered. Here we argue that a gene network approach provides tools to explain this phenomenon since it indicates potential alleles co-evolving in a compensatory way. We identified alleles of the vitamin D metabolism and pigmentation pathways segregated together, but in different proportions, in agriculturalists and hunter-gatherers. Finally, we highlight how an evolutionary approach can be useful to understand current topics of medical interest.

Time trends of vitamin D concentrations in northern Sweden between 1986 and 2014: a population-based cross-sectional study

Purpose

Vitamin D, produced through cutaneous photosynthesis or ingested via foods or supplements, has generated considerable research interest due to its potential health effects. However, epidemiological data on the time trends of vitamin D status are sparse, especially from northern Europe. We examined the time trend of vitamin D concentrations in northern Sweden between 1986 and 2014.

Methods

We used data on 11,129 men and women (aged 25–74 years) from seven population-based surveys (the Northern Sweden MONICA study), recruited between 1986 and 2014. Serum vitamin D (25-hydroxyvitamin D) status was measured using a one-step immunoassay (Abbott Architect). Multivariable linear regression models, adjusted for age, sex, and a number of other variables, were used to estimate the time trend of vitamin D concentrations.

Results

The mean value of vitamin D in the entire study population was 19.9 ng/mL [standard deviation (SD) 7.9], with lower values in men (19.4 ng/mL; SD 7.5) than in women (20.5 ng/mL; SD 8.2). Using the survey in 1986 as reference category, the multivariable-adjusted mean difference [95% confidence interval (CI)] in ng/mL was 2.7 (2.2, 3.3) in 1990, 3.2 (2.7, 3.7) in 1994, 1.6 (1.0, 2.1) in 1999, − 2.0 (− 2.5, − 1.4) in 2004, 1.0 (0.4, 1.5) in 2009, and 3.1 (2.5, 3.6) in 2014.

Conclusion

In this large cross-sectional study, we observed no clear upward or downward trend of vitamin D concentrations in northern Sweden between 1986 and 2014.

Electronic supplementary material

The online version of this article (10.1007/s00394-019-02142-x) contains supplementary material, which is available to authorized users.

Latitude continues to be significantly associated with the prevalence of multiple sclerosis: an updated meta-analysis

OBJECTIVES

Previous studies have demonstrated a strong latitudinal gradient in multiple sclerosis (MS) prevalence. Herein, we present a meta-analysis of the latitudinal gradient of MS prevalence including studies published since our 2011 review, seeking to assess the latitudinal gradient and whether it has changed since our previous analysis.

METHODS

Studies published up to December 2018 were located via Embase, Web of Knowledge and PubMed, using standardised search terms; data were extracted from peer-reviewed studies and these studies added to those from our previous analysis. Where age-specific data were available, prevalence estimates were age-/sex-standardised to the 2009 European population. Prevalence estimates were adjusted for study prevalence year and ascertainment methods. The latitudinal association with MS prevalence was assessed by meta-regression.

RESULTS

A total of 94 studies met inclusion criteria, yielding 230 new prevalence points and 880 altogether with those from the prior study. There was a significant positive gradient in time-corrected MS prevalence with increasing latitude (5.27/100 000 per degree latitude), attenuating slightly to 4.34/100 000 on age-standardisation, these associations persisting on adjustment for ascertainment method. Of note, the age-standardised gradient was consistently significantly enhanced from our previous study, regardless of whether it was as-measured, time-corrected or adjusted for ascertainment methods. Certain areas, such as the Scandinavian and Atlantic Coast/Central Europe regions, showed changes in MS prevalence gradient over time, but other regional gradients were similar.

CONCLUSIONS

This new meta-analysis confirms that MS prevalence is still strongly positively associated with increasing latitude and that the gradient is increasing, suggesting that potentially modifiable environmental factors, such as sun exposure, are still strongly associated with MS risk.

Evolutionary Perspective in Rickets and Vitamin D

Modern lifestyle limits our exposure to sunlight, which photosynthesizes vitamin D in the skin, and the incidence of nutritional rickets has been resurging. Vitamin D is one of the first hormones; it is photosynthesized in all organism from the phytoplankton to mammals. A selective sweep of the promoter of the vitamin D receptor (VDR) happened as soon as Homo sapiens migrated out of Africa; it co-adapted with skin color genes to provide adaptation to latitudes and the levels of exposure to ultraviolet (UV)B radiation along the route out of Africa. Exposure to UVB radiation balances the need for vitamin D photosynthesis and degradation of folic acid by UVB radiation. Skin color follows a latitude distribution: the darkest populations dwell in the tropical belt; and the fair-skinned populations inhabit the northern countries. Due to their greater need for calcium during their reproductive life, the skin color of women is lighter- than that of men. Vitamin D is essential for mineral homeostasis and has a wide variety of non-skeletal functions, of which the most important for natural selection is a regulatory function in the innate immune system. In the human fossil record, vitamin D deficiency coincided with bone tuberculosis. About 6,000 years ago, a diet which included cow's milk provided Neolithic humans with twice as much calcium and was more alkaline than that of its Paleolithic predecessors. Adiposity is negatively associated with the vitamin D status and obese individuals require 2-3 times more vitamin D than non-obese individuals to normalize circulating 25OHD levels. In an era of an obesity epidemic, we need more research to determine whether adiposity should be considered when determining the dietary requirements for vitamin D and calcium and the optimal serum 25OHD levels.

Vitamin D status in a multi-ethnic population of northern Norway: the SAMINOR 2 Clinical Survey

Objective

To investigate serum 25-hydroxyvitamin D (S-25(OH)D) concentration in a multi-ethnic population of northern Norway and determine predictors of S-25(OH)D, including Sami ethnicity.

Design

Cross-sectional data from the second survey of the Population-based Study on Health and Living Conditions in Regions with Sami and Norwegian Populations (the SAMINOR 2 Clinical Survey, 2012–2014). S-25(OH)D was measured by the IDS-iSYS 25-Hydroxy Vitamin Dˢ assay. Daily dietary intake was assessed using an FFQ. BMI was calculated using weight and height measurements.

Setting

Ten municipalities of northern Norway (latitude 68°–70°N).

Participants

Males (n 2041) and females (n 2424) aged 40–69 years.

Results

Mean S-25(OH)D in the study sample was 64·0 nmol/l and median vitamin D intake was 10·3 µg/d. The prevalence of S-25(OH)D<30 nmol/l was 1·9 % and <50 nmol/l was 24·7 %. In sex-specific multivariable linear regression models, older age, blood sample collection in September–October, solarium use, sunbathing holiday, higher alcohol intake (in females), use of cod-liver oil/fish oil supplements, use of vitamin/mineral supplements and higher intakes of vitamin D were significantly associated with higher S-25(OH)D, whereas being a current smoker and obesity were associated with lower S-25(OH)D. These factors explained 21–23 % of the variation in S-25(OH)D.

Conclusions

There were many modifiable risk factors related to S-25(OH)D, however no clear ethnic differences were found. Even in winter, the low prevalence of vitamin D deficiency found among participants with non-Sami, multi-ethnic Sami and Sami self-perceived ethnicity was likely due to adequate vitamin D intake.

Cancer Incidence and Mortality in Greenland 1983-2014 - Including Comparison With the Other Nordic Countries

BACKGROUND

During the last decades, social and life-style changes in Greenland have led to an increase in the incidence of several non-communicable diseases. Our aim is to present the cancer incidence and mortality in Greenland and compare the results with the other Nordic countries.

METHODS

The data stems from The Danish Cancer Registry and The Danish Register of Causes of Death. Comparable data on cancer incidence and mortality in Denmark, Finland, Iceland, Norway, Sweden, and Greenland are available through collaboration between Nordic Cancer Registries (NORDCAN). We included all individuals residing in Greenland and diagnosed with or died of a cancer from 1983 to 2014.

FINDINGS

The total number of cancer cases in Greenland for the study period was 4716 and there were 3231 cancer deaths. Respiratory and gastrointestinal cancers had the highest incidence as well as mortality in Greenland for the entire time period and for both sexes. Compared to the other Nordic countries, Greenland had significantly higher incidence and mortality rates for several cancers. Cancer of the lip, oral cavity, and pharynx, respiratory cancer, and cancer of unknown sites had the highest incidence rate ratios (2.3-3.9) and mortality rate ratios (2.7-9.9) for both sexes. The time trend from 1983 to 2014 showed a significant increase in cancer incidence in Greenland with nearly the same incidence level as the other Nordic countries. While the cancer mortality decreased in the other Nordic countries during the time period studied, there was no change in the cancer-specific mortality in Greenland.

INTERPRETATIONS

The trends in cancer incidence and mortality in Greenland compared to the other Nordic countries have not been reported earlier. These data underline a need to focus on cancer-specific mortality in Greenland and prevention of high-incidence cancers related to well-established risk factors.

Sleep, physical activity, waist circumference and diet as factors that influence health for reproductive age women in northern Greenland

BACKGROUND

This study explored community and individual factors that influence the health of reproductive age women in a settlement in northern Greenland. This is important because Greenland has a declining population, a high abortion rate and because of projected environmental shifts due to climate change.

METHODS

This study collected mixed methods data to explore diet, physical activity, sleep and waist circumference for reproductive age women in Kullorsuaq, Greenland. The daily steps and sleeping hours of 13 reproductive age women were measured using activity monitoring bracelets. Waist circumference measurements and in-depth interviews about daily eating and physical activity were conducted with 15 participants and ethnographic participant observations were recorded using field notes.

RESULTS

Waist circumference measurements were above recommended cutoffs established by the World Health Organization. Physical activity measured by daily steps was within the 'active' range using the cutoff points established by Tudor and Locke. Physical activity is social and is important for communal relationships. Sleeping hours were within normal ranges based on US guidelines; however, the quality of this sleep, its variability across seasons and cultural expectations of what healthy sleep means must be further explored. Diets of women included a mixture of locally harvested meats and imported packaged foods. Study participants experienced less satiety and reported getting hungrier faster when eating packaged foods. This research took place in Spring 2016 and women reported that their sleep, physical activity and diet fluctuate seasonally.

CONCLUSION

The reported findings suggest further investigation of sleep, diet and physical activity combined with the measurement of reproductive hormones to determine linkages between lifestyle factors and reproductive health outcomes is needed.

Associations between vitamin D status and atherosclerosis among Inuit in Greenland

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.

Declines in traditional marine food intake and vitamin D levels from the 1960s to present in young Alaska Native women

OBJECTIVE

To measure the trends in traditional marine food intake and serum vitamin D levels in Alaska Native women of childbearing age (20-29 years old) from the 1960s to the present.

DESIGN

We measured a biomarker of traditional food intake, the δ15N value, and vitamin D level, as 25-hydroxycholecalciferol (25(OH)D3) concentration, in 100 serum samples from 20-29-year-old women archived in the Alaska Area Specimen Bank, selecting twenty-five per decade from the 1960s to the 1990s. We compared these with measurements of red-blood-cell δ15N values and serum 25(OH)D3 concentrations from 20-29-year-old women from the same region collected during the 2000s and 2010s in a Center for Alaska Native Health Research study.

SETTING

The Yukon Kuskokwim Delta region of south-west Alaska.

SUBJECTS

Alaska Native women (n 319) aged 20-29 years at the time of specimen collection.

RESULTS

Intake of traditional marine foods, as measured by serum δ15N values, decreased significantly each decade from the 1960s through the 1990s, then remained constant from the 1990s through the present (F 5,306=77·4, P<0·0001). Serum vitamin D concentrations also decreased from the 1960s to the present (F 4,162=26·1, P<0·0001).

CONCLUSIONS

Consumption of traditional marine foods by young Alaska Native women dropped significantly between the 1960s and the 1990s and was associated with a significant decline in serum vitamin D concentrations. Studies are needed to evaluate the promotion of traditional marine foods and routine vitamin D supplementation during pregnancy for this population.

Associations between Vitamin D Status and Type 2 Diabetes Measures among Inuit in Greenland May Be Affected by Other Factors

OBJECTIVE

Epidemiological studies have provided evidence of an association between vitamin D insufficiency and type 2 diabetes. Vitamin D levels have decreased among Inuit in Greenland, and type 2 diabetes is increasing. We hypothesized that the decline in vitamin D could have contributed to the increase in type 2 diabetes, and therefore investigated associations between serum 25(OH)D3 as a measure of vitamin D status and glucose homeostasis and glucose intolerance in an adult Inuit population.

METHODS

2877 Inuit (≥18 years) randomly selected for participation in the Inuit Health in Transition study were included. Fasting- and 2hour plasma glucose and insulin, C-peptide and HbA1c were measured, and associations with serum 25(OH)D3 were analysed using linear and logistic regression. A subsample of 330 individuals who also donated a blood sample in 1987, were furthermore included.

RESULTS

After adjustment, increasing serum 25(OH)D3 (per 10 nmol/L) was associated with higher fasting plasma glucose (0.02 mmol/L, p = 0.004), 2hour plasma glucose (0.05 nmol/L, p = 0.002) and HbA1c (0.39%, p<0.001), and with lower beta-cell function (-1.00 mmol/L, p<0.001). Serum 25(OH)D3 was positively associated with impaired fasting glycaemia (OR: 1.08, p = 0.001), but not with IGT or type 2 diabetes.

CONCLUSIONS

Our results did not support an association between low vitamin D levels and risk of type 2 diabetes. Instead, we found weak positive associations between vitamin D levels and fasting- and 2hour plasma glucose levels, HbA1c and impaired fasting glycaemia, and a negative association with beta-cell function, underlining the need for determination of the causal relationship.

Are the current Australian sun exposure guidelines effective in maintaining adequate levels of 25-hydroxyvitamin D?

An adequate vitamin D status, as measured by serum 25-hydroxyvitamin D (25(OH)D) concentration, is important in humans for maintenance of healthy bones and muscle function. Serum 25(OH)D concentration was assessed in participants from Melbourne, Australia (37.81S, 144.96E), who were provided with the current Australian guidelines on sun exposure for 25(OH)D adequacy (25(OH)D ≥50 nmol/L). Participants were interviewed in February (summer, n=104) and August (winter, n=99) of 2013. Serum 25(OH)D concentration was examined as a function of measures of sun exposure and sun protection habits with control of key characteristics such as dietary intake of vitamin D, body mass index (BMI) and skin colour, that may modify this relationship. The mean 25(OH)D concentration in participants who complied with the current sun exposure guidelines was 67.3 nmol/L in summer and 41.9 nmol/L in winter. At the end of the study, 69.3% of participants who complied with the summer sun exposure guidelines were 25(OH)D adequate, while only 27.6% of participants who complied with the winter sun exposure guidelines were 25(OH)D adequate at the end of the study. The results suggest that the current Australian guidelines for sun exposure for 25(OH)D adequacy are effective for most in summer and ineffective for most in winter. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Vitamin D-rich marine Inuit diet and markers of inflammation - a population-based survey in Greenland

The traditional Inuit diet in Greenland consists mainly of fish and marine mammals, rich in vitamin D. Vitamin D has anti-inflammatory capacity but markers of inflammation have been found to be high in Inuit living on a marine diet. Yet, the effect of vitamin D on inflammation in Inuit remains unsettled. This led us to investigate the association between vitamin D and markers of inflammation in a population with a high intake of a marine diet. We studied 535 Inuit and non-Inuit living in West and East Greenland. Information concerning dietary habits was obtained by interview-based FFQ. Blood samples were drawn for analysis of 25-hydroxyvitamin D, high-sensitivity C-reactive protein (hsCRP) and chitinase-3-like protein 1(YKL-40). Participants were divided into three groups based on degree of intake of the traditional Inuit diet. The diet groups (Inuit diet/mixed diet/imported foods) were associated with vitamin D levels in serum (74·2, 69·8 and 52·9 nm; P < 0·001), hsCRP (1·6, 1·4 and 1·3 mg/l; P = 0·002) and YKL-40 (130, 95 and 61 ng/ml; P < 0·001), respectively. YKL-40 level decreased with rising vitamin D level in Inuit (Inuit diet P = 0·002; mixed diet P = 0·011). YKL-40 was lower in groups with higher vitamin D levels after adjusting for other factors known to influence inflammation (P < 0·001). This was not seen for hsCRP. In conclusion, vitamin D and markers of inflammation vary in parallel with the intake of the marine Inuit diet. Vitamin D levels were inversely associated with YKL-40 levels, but no association with hsCRP was found. The hypothesised anti-inflammatory effect of vitamin D was not supported. Other factors in the marine diet may be speculated to influence inflammation.

An efficient case finding strategy to diagnose osteoporosis in a developing society with low treatment frequency

OBJECTIVES

Osteoporosis is a debilitating condition with rising frequency of fragility fractures with advancing age. Life expectancy increases in developing societies with the emergence of osteoporosis. There is a need for a simple protocol to diagnose fractures that merit treatment for osteoporosis.

METHODS

Evaluation of all consecutive lateral chest radiographs performed at the National Hospital in the capital city in Greenland over a 3-month period for vertebral body heights at the anterior, middle and posterior regions. Use of anti-osteoporotic drug was evaluated from records of dispensed drugs from Greenland National Pharmacy.

RESULTS

1869 vertebrae were evaluated on radiographs from 203 subjects. On average 9.2 vertebrae (range 5-13) qualified for evaluation in each individual. Median (range) age was 55 (30-82) years. Any vertebral deformity above 25 (20) % was seen in 28.6 (50.2) %. More than one fracture was seen in 10.3 (27.1) %. Fractures occurred in 18.5 (36.9) % of patients from the General Medicine Clinic and in 33.3 (56.5) % of inpatients (p = 0.029). The occurrence of vertebral fractures increased with age (p < 0.001) and hosting more than one vertebral fracture was markedly more frequent after the age of 60 years [OR, 95 % CI 9.6, 3.1-30 (5.7, 2.9-11); p < 0.001] after correction for gender in logistic regressions. The National Pharmacy handed out anti-osteoporotic drugs equal to the treatment of 36 individuals.

CONCLUSIONS

Vertebral fractures that merit treatment can be readily diagnosed from lateral chest radiographs taken in routine clinical work-up. They are common in Greenland as demonstrated by this simple protocol to improve diagnosis and treatment of osteoporosis in a developing society.

Adequate vitamin D levels in a Swedish population living above latitude 63°N: The 2009 Northern Sweden MONICA study

Background

Even though vitamin D is mainly produced by exposure to sunlight, little is known regarding vitamin D levels in populations living in sub-Arctic areas with little or no daylight during winter.

Objective

We describe distributions of vitamin D3 and the prevalence of adequate levels in a population living above 63°N.

Design

We sampled 1,622 randomly selected subjects, aged 25–74 years, between January and May, 2009, as part of the Northern Sweden MONICA study (69.2% participation rate). By using HPLC, 25(OH) vitamin D3 was analysed. Levels used for definitions were deficient, D3<25 nmol/l (<10 ng/ml); insufficient, D3 25–49.9 nmol/l (10–20 ng/ml); and adequate, D3≥50 nmol/l (20 ng/ml).

Results

Mean (median) level of vitamin D3 was 65.2 (63.6) nmol/l in men and 71.0 (67.7) nmol/l in women. Adequate levels were found in 79.2%, more often in women (82.7%) than in men (75.6%). Only 0.7% of the population were vitamin D3–deficient but 23.1% of men and 17.1% of women had insufficient levels. Levels of vitamin D3 increased with age and insufficient status was most common among those aged 25–34 years, 41.0% in men and 22.3% in women.

If subjects using vitamin D-supplementation are excluded, the population level of D3 is 1–2 nmol/l lower than in the general population across sex- and age groups. There were no differences between the northern or the southern parts, between urban or rural living or according to educational attainment. Those subjects born outside of Sweden or Finland had lower levels.

Conclusion

The large majority living close to the Arctic Circle in Sweden have adequate D3 levels even during the second half of the dark winter. Subjects with D3 deficiency were uncommon but insufficient levels were often found among young men.