• 25-hydroxyvitamin D and cardiovascular disease in patients with systemic lupus erythematosus: data from a large international inception cohort.

      Lertratanakul, Apinya; Wu, Peggy; Dyer, Alan; Urowitz, Murray; Gladman, Dafna; Fortin, Paul; Bae, Sang-Cheol; Gordon, Caroline; Clarke, Ann; Bernatsky, Sasha; et al. (Wiley-Blackwell, 2014-08)
      An association between 25-hydroxyvitamin D (25[OH]D; vitamin D) deficiency and increased cardiovascular (CV) risk factors and CV disease (CVD) has been shown in general population studies. Vitamin D deficiency has been noted in systemic lupus erythematosus (SLE), and CVD is a major cause of morbidity and mortality in SLE. The objectives of this study were to estimate the associations of 25(OH)D levels with CV risk factors and to determine whether low baseline 25(OH)D levels predict future CV events in patients participating in an international inception cohort.
    • Associations of physical activity with vitamin D status depends on obesity status in old adults.

      OG, Geirsdottir; M, Chang; Pv, Jonsson; I, Thorsdottir; A, Ramel; 1The Icelandic Gerontological Research Center, Reykjavik, Iceland; Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland. 2The Icelandic Gerontological Research Center, Reykjavik, Iceland; Sport Science, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland. 3The Icelandic Gerontological Research Center, Reykjavik, Iceland; Department of Geriatrics, National University Hospital of Iceland, Reykjavik, Iceland. 4School of Health Sciences, University of Iceland, Reykjavik, Iceland. 5The Icelandic Gerontological Research Center, Reykjavik, Iceland; Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland. Electronic address: alfonsra@hi.is. (Elsevier, 2020-07-12)
      Purpose: Obesity has been associated with low 25-hydroxy-vitamin D (25OHD). The causes of hypovitaminosis D in obese individuals are not known. The present work aimed to investigate 25OHD in obese and normal-/overweight subjects with consideration of leisure-time physical activity (LTPA). Methods: Community-dwelling old adults (N = 229, 73.7 ± 5.7yrs, 58.2% female) from the Reykjavik capital area in Iceland participated in this cross-sectional study. LTPA, vitamin D intake, body composition and background variables were assessed. 25OHD was measured in fasting blood samples. Results: Mean LTPA was 5.7 ± 5.6 h/week and the common activities were walking and gardening. Mean 25OHD was 66.7 ± 28.1 nmol/L and 8.5/21.2% were below 30 and 50 nmol/L, respectively. Obese participants (n = 84) had lower 25OHD (-11.0 ± 3.8 nmol/L,P < 0.001) and lower LTPA (-2.5 + 0.8 h/week,P = 0.001) than normal-/overweight subjects (n = 145). Linear models showed that LTPA (h/week) was associated with higher 25OHD in normal-/overweight participants only (1.3 nmol/L, P < 0.001) but not in obese (-0.7 nmol, P = 0.245). Fish oil intake was associated with higher 25OHD both in normal-/overweight (19.2 ± 4.5 nmol/L, P = 0.001) and obese subjects (13.4 ± 5.3 nmol/L, P = 0.013). Conclusions: Obese community-dwelling old adults in Iceland have lower 25OHD than their normal-/overweight counterparts. LTPA was associated with a higher 25OHD in normal-/overweight, but not in obese participants. However, fish oil was associated with higher 25OHD independently from obesity status. Thus, vitamin D supplementation is important for obese old adults to maintain vitamin D levels. Keywords: Aging; Fish oil; Leisure-time physical activity; Obesity; Vitamin D.
    • Depression and serum 25-hydroxyvitamin D in older adults living at northern latitudes - AGES-Reykjavik Study.

      Imai, Cindy M; Halldorsson, Thorhallur I; Eiriksdottir, Gudny; Cotch, Mary F; Steingrimsdottir, Laufey; Thorsdottir, Inga; Launer, Lenore J; Harris, Tamara; Gudnason, Vilmundur; Gunnarsdottir, Ingibjorg; et al. (Cambridge University Press, 2015)
      Low vitamin D status may be associated with depression. Few studies have examined vitamin D and depression in older adults living at northern latitudes. The present study cross-sectionally investigated serum 25-hydroxyvitamin D (25(OH)D) status and depression among 5006 community-dwelling older persons (66-96 years) living in Iceland (latitudes 64-66°N). Depressive symptoms were measured by the fifteen-item Geriatric Depression Scale (GDS-15). Current major depressive disorder was assessed according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria. Serum 25(OH)D was analysed using chemiluminescence immunoassay and categorised into three groups: deficient (<30 nmol/l); inadequate (30-49·9 nmol/l); and adequate (≥50 nmol/l). There were twenty-eight (2 %) men and fifty (1 %) women with current major depressive disorder. Mean GDS-15 scores for men and women with adequate vitamin D concentrations were 2·1 and 2·2, respectively. Men and women with deficient v. adequate vitamin D status had more depressive symptoms (higher GDS-15 scores) (difference 0·7 (95 % CI 0·4, 0·9) and 0·4 (95 % CI 0·1, 0·6), respectively). Furthermore, men with deficient vitamin D status were more likely to have current major depressive disorder (adjusted OR 2·51; 95 % CI 1·03, 6·13) compared with men with adequate vitamin D status. Associations among women were not significant. In this older population living at northern latitudes, deficient vitamin D status may be associated with depression. Further investigations are warranted to evaluate the pathways that may be associated with risk of depression among older adults.
    • Effects of a healthy Nordic diet on plasma 25-hydroxyvitamin D concentration in subjects with metabolic syndrome: a randomized, placebo-controlled trial (SYSDIET).

      Brader, Lea; Rejnmark, Lars; Carlberg, Carsten; Schwab, Ursula; Kolehmainen, Marjukka; Rosqvist, Fredrik; Cloetens, Lieselotte; Landin-Olsson, Mona; Gunnarsdottir, Ingibjorg; Poutanen, Kaisa S; et al. (Springer, 2014-06)
      At northern latitudes, vitamin D is not synthesized endogenously during winter, causing low plasma 25-hydroxyvitamin D (25(OH)D) concentrations. Therefore, we evaluated the effects of a healthy Nordic diet based on Nordic nutrition recommendations (NNR) on plasma 25(OH)D and explored its dietary predictors.
    • Infant Feeding, Vitamin D and IgE Sensitization to Food Allergens at 6 Years in a Longitudinal Icelandic Cohort.

      Thorisdottir, Birna; Gunnarsdottir, Ingibjorg; Vidarsdottir, Anna Gudrun; Sigurdardottir, Sigurveig; Birgisdottir, Bryndis Eva; Thorsdottir, Inga; 1 Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, 101 Reykjavik, Iceland. bth50@hi.is. 2 Faculty of Sociology, Anthropology and Folkloristics, School of Social Sciences, University of Iceland, 101 Reykjavik, Iceland. bth50@hi.is. 3 Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, 101 Reykjavik, Iceland. 4 Department of Immunology, Landspitali University Hospital, 101 Reykjavik, Iceland. 5 Faculty of Medicine, University of Iceland, 101 Reykjavik, Iceland. 6 The Allergy Outpatient Department, Landspitali University Hospital, 108 Reykjavik, Iceland. 7 School of Health Sciences, University of Iceland, 101 Reykjavik, Iceland. (MDPI Publishing, 2019-07-23)
      Nordic Nutrition Recommendations (NNR) recommend exclusive breastfeeding until 6 months, partial breastfeeding until 1 year or longer and irrespective of breastfeeding, avoiding solid foods before 4 months. Strong evidence was found for benefits of breastfeeding regarding growth and infections but limited/inconclusive evidence regarding atopic disease and asthma. Vitamin D is of special interest in the Nordic diet. The aim of this prospective study was to compare infant feeding and vitamin D between immunoglobulin E (IgE) sensitized (n = 14) and non-sensitized (n = 130) children at 6 years. Information on diet and vitamin D supplement use were collected with dietary recall (<5 months), 1-d food records (5 and 6 months) and 3-d weighed food records (12 months and 6 years). Serum-specific IgE-antibodies against milk, egg, cod, wheat, soy and peanut (cut-off specific IgE ≥ 0.35 kUA/L) were measured at 6 years and serum 25-hydroxyvitamin D at 12 months and 6 years. At 4 months, 57% of IgE sensitized vs. 23% of non-sensitized children (p < 0.01) had received solid food. At 12 months, IgE sensitized children had a lower intake of vitamin D (median (25th, 75th percentiles): 3.9 μg/d (3.2, 7.2) vs. 8.1 μg/d (4.4, 12.3), p = 0.03) and at 6 years, fewer used vitamin D supplements regularly (23% vs. 56%, p = 0.03). Introduction of solid foods prior to 4 months increased the odds of IgE-sensitization, OR = 4.9 (95%, CI = 1.4-16.6) and vitamin D supplement at 6 years decreased the odds of IgE-sensitization, OR = 0.2 (95%, CI = 0.1-0.98), adjusting for maternal smoking. These observations support the NNR in their recommendation against introducing complementary solid foods before the age of 4 months. Furthermore, they support encouraging vitamin D intake for young children at northern latitudes.
    • Insufficient autumn vitamin D intake and low vitamin D status in 7-year-old Icelandic children.

      Bjarnadottir, Adda; Kristjansdottir, Asa Gudrun; Hrafnkelsson, Hannes; Johannsson, Erlingur; Magnusson, Kristjan Thor; Thorsdottir, Inga; 1 Unit for Nutrition Research, Landspitali-University Hospital & Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland, Laeknagardur, Vatnsmyrarvegur 16, 101 Reykjavík, Iceland. 22 Center for Sport and Health Sciences, School of Education, University of Iceland, Reykjavík, Iceland. (Cambridge Univ Press, 2014-01-22)
      The aim was to investigate autumn vitamin D intake and status in 7-year-old Icelanders, fitting BMI and cardiorespiratory fitness as predictors.
    • Lifestyle and 25-hydroxy-vitamin D among community-dwelling old adults with dementia, mild cognitive impairment, or normal cognitive function.

      Eymundsdottir, Hrafnhildur; Chang, M; Geirsdottir, O G; Gudmundsson, L S; Jonsson, P V; Gudnason, V; Launer, L; Jonsdottir, M K; Ramel, A; 1Faculty of Food Science and Nutrition, University of Iceland, Reykjavík, Iceland. hre6@hi.is. 2The Icelandic Gerontological Research Center, The National University Hospital of Iceland, Tungata 26, 101, Reykjavík, Iceland. hre6@hi.is. 3The Icelandic Gerontological Research Center, The National University Hospital of Iceland, Tungata 26, 101, Reykjavík, Iceland. 4Faculty of Health Promotion, Sport and Leisure Studies, School of Education, University of Iceland, Reykjavík, Iceland. 5Faculty of Food Science and Nutrition, University of Iceland, Reykjavík, Iceland. 6Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Reykjavík, Iceland. 7Faculty of Medicine, University of Iceland, Reykjavík, Iceland. 8Department of Geriatrics, The National University Hospital of Iceland, Reykjavík, Iceland. 9Icelandic Heart Association, Kópavogur, Iceland. 10Laboratory of Epidemiology and Population Sciences, National Institute On Aging, National Institutes of Health (NIH), Bethesda, MD, USA. 11Department of Psychology, Reykjavik University, Reykjavík, Iceland. 12Mental Health Services (Memory Clinic) Landspitali-The National University Hospital of Iceland, Reykjavík, Iceland. (Springer, 2020-04-04)
      ackground: Several studies have indicated that older adults with cognitive impairment have a poorer lifestyle than their healthy peers including lower 25-hydroxy-vitamin D levels (25OHD). Aim: To investigate the associations between lifestyle and 25OHD depending on cognitive status among old adults. Methods: Community-dwelling old adults (65-96 years) participated in this cross-sectional study based on the Age-Gene/Environment-Susceptibility-Reykjavik-Study. The analytical sample included 5162 subjects who were stratified by cognitive status, i.e., dementia (n = 307), mild cognitive impairment (MCI, n = 492), and normal cognitive status (NCS, n = 4363). Lifestyle variables were assessed and 25OHD was measured. The associations between lifestyle and 25OHD were calculated using linear models correcting for potential confounders. Results: According to linear regression models, 25OHD was significantly lower in older people with dementia (53.8 ± 19.6 nmol/L) than in NCS participants (57.6 ± 17.7 nmol/L). Cod liver oil (7.1-9.2 nmol/L, P < 0.001) and dietary supplements (4.4-11.5 nmol/L, P < 0.001) were associated with higher 25OHD in all three groups. However, physical activity ≥ 3 h/week (2.82 nmol/L, P < 0.001), BMI < 30 kg/m2 (5.2 nmol/L, P < 0.001), non-smoking (4.8 nmol/L, P < 0.001), alcohol consumption (2.7 nmol/L, P < 0.001), and fatty fish consumption ≥ 3x/week (2.6 nmol/L, P < 0.001) were related to higher 25OHD in NCS only, but not in participants with dementia or MCI. Discussion: Older people living in Iceland with dementia are at higher risk for 25OHD deficiency when compared to healthy individuals. Physical activity reported among participants with dementia, and MCI is low and is not significantly associated with 25OHD. Conclusions: Lifestyle factors among NCS participants are associated with 25OHD levels. Importantly, healthy lifestyle should be promoted among individuals with MCI and dementia.
    • Plasma 25-hydroxyvitamin D2 and D3 levels and incidence of postoperative atrial fibrillation.

      Skuladottir, G V; Cohen, A; Arnar, D O; Hougaard, D M; Torfason, B; Palsson, R; Indridason, O S; [ 1 ] Univ Iceland, Sch Hlth Sci, Dept Physiol, Reykjavik, Iceland [ 2 ] Univ Iceland, Fac Med, Sch Hlth Sci, Reykjavik, Iceland [ 3 ] Statens Serum Inst, Dept Congenital Disorders, DK-2300 Copenhagen, Denmark [ 4 ] Landspitali, Internal Med Serv, Reykjavik, Iceland [ 5 ] Landspitali, Surg Serv, Reykjavik, Iceland (Cambridge Univ Press, 2016)
      Low circulating levels of total 25-hydroxyvitamin D (25(OH)D) have been associated with an increased risk of adverse effects after cardiac surgery. The metabolites, 25(OH)D2 and 25(OH)D3, provide a good index of vitamin D status. In this study, we examined the association between preoperative plasma levels of total 25(OH)D, 25(OH)D2 and 25(OH)D3 and the risk of postoperative atrial fibrillation (POAF) following open heart surgery. The levels of plasma 25(OH)D2 and 25(OH)D3 in 118 patients, who underwent coronary artery bypass grafting and/or valvular surgery, were measured immediately prior to surgery and on postoperative day 3 by liquid chromatography-tandem mass spectrometry. Patients who developed POAF had higher median plasma levels of 25(OH)D2 than those who remained in sinus rhythm (SR) (P = 0·003), but no significant difference was noted in levels of 25(OH)D3 or total 25(OH)D between the two groups (P > 0·05). By univariate analysis, patients with total 25(OH)D and 25(OH)D2 levels above the median had higher frequency of POAF (P < 0·05) and the incidence of POAF increased significantly with each higher quartile of preoperative plasma levels of 25(OH)D2 (P = 0·001), an association that was independent of confounding factors. In both the SR and POAF groups, the median plasma levels of 25(OH)D2, 25(OH)D3 and total 25(OH)D were lower (P < 0·05) on the third postoperative day compared with preoperatively. Our findings demonstrate that higher plasma levels of 25(OH)D2 are associated with increased risk of POAF, while this is not the case for 25(OH)D3 or total 25(OH)D. The reason for these discrepant results is not clear but warrants further study.
    • Severe vitamin D deficiency is common in critically ill patients at a high northern latitude.

      Kvaran, R B; Sigurdsson, M I; Skarphedinsdottir, S J; Sigurdsson, G H; [ 1 ] Landspitali Univ Hosp, Dept Anaesthesia & Intens Care Med, IS-101 Reykjavik, Iceland   Organization-Enhanced Name(s)      Landspitali National University Hospital [ 2 ] Univ Iceland, Fac Med, Reykjavik, Iceland [ 3 ] Brigham & Womens Hosp, Dept Anaesthesia Perioperat & Pain Med, 75 Francis St, Boston, MA 02115 USA (Wiley-Blackwell, 2016-10)
      Critically ill patients at southern latitudes have been shown to have low vitamin D levels that were associated with prolonged hospital stay. To our knowledge no studies have been conducted on vitamin D status amongst critically ill patients at high northern latitudes. Despite the Icelandic population traditionally taking vitamin D supplements, we hypothesized that the majority of critically ill patients in Reykjavik, Iceland have low vitamin D levels.
    • Vitamin D - a systematic literature review for the 5th edition of the Nordic Nutrition Recommendations.

      Lamberg-Allardt, Christel; Brustad, Magritt; Meyer, Haakon E; Steingrimsdottir, Laufey; Univ Helsinki, Dept Food & Environm Sci, FI-00014 Helsinki, Finland, UIT Arctic Univ Norway, Tromso, Norway, Univ Oslo, Inst Hlth & Soc, Dept Community Med, Oslo, Norway, Norwegian Inst Publ Hlth, Oslo, Norway, Landspitali Univ Hosp, Unit Nutr Res, Reykjavik, Iceland, Univ Iceland, Reykjavik, Iceland (Co-Action publishing, 2013)
      The present literature review is part of the NNR5 project with the aim of reviewing and updating the scientific basis of the 4th edition of the Nordic Nutrition Recommendations (NNR) issued in 2004.
    • Vitamin D and Associations with Walking Ability in Community- Dwelling Elderly Adults

      OG, Geirsdottir; A, Ramel; 2Unit for Nutrition Research, National University Hospital of Iceland & Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland 3Department of Geriatrics, National University Hospital of Iceland, Reykjavik, Iceland (SciTechnol, 2016)
      Epidemiological studies have suggested a positive association between vitamin D status and physical function. In order to improve our understanding of vitamin D and physical function, the present analysis investigated the associations between vitamin D status and walking ability in community-dwelling elderly adults, with particular consideration of body fatness and physical activity. This was a secondary, cross-sectional analysis, using baseline data from a randomized, controlled trial. The subjects were elderly adults living in a community (N=236, 73.7 ± 5.7 years, 58.2% female). BMI, body composition and serum 25-OH vitamin D were measured. Walking ability was assessed by the distance covered in a six-minute walk (6MWD). The dietary intake of vitamin D was estimated with a 3-day weighed food record, and physical activity was self-reported. The average serum 25-OH vitamin D levels mean was 67 ± 28 nmol/l. Serum 25-OH vitamin D correlated with self-reported physical activity in minutes per week (r=0.222, P=0.001). It also correlated with physical function in the 6MWD (r=0.264, P=0.037). Dietary vitamin D correlated with serum OH-25 vitamin D (r=0.297, P <0.001). Serum 25-OH vitamin D correlated negatively with BMI and fat mass (r= -0.165, P= 0.012 and r=-0.145, P=0.030). In this cross-sectional analysis we found associations between walking ability and vitamin D status in community-dwelling elder adults. However, these associations were not independent and were mostly explained by the confounding factors of BMI and self-reported physical activity.
    • Vitamin D intake and status in 12-month-old infants at 63-66° N.

      Thorisdottir, Birna; Gunnarsdottir, Ingibjorg; Steingrimsdottir, Laufey; Palsson, Gestur I; Thorsdottir, Inga; Landspitali Univ Hosp, Unit Nutr Res, IS-101 Reykjavik, Iceland, Univ Iceland, Sch Hlth Sci, Fac Food Sci & Nutr, IS-101 Reykjavik, Iceland, Landspitali Univ Hosp, Childrens Hosp, IS-101 Reykjavik, Iceland (MDPI AG, 2014)
      The objective was to assess the vitamin D status in healthy 12-month-old infants in relation to quantity and sources of dietary vitamin D, breastfeeding and seasons. Subjects were 76 12-month-old infants. Serum levels of 25-hydroxyvitamin D (25(OH)D) ≥ 50 nmol/L were considered indicative of vitamin D sufficiency and 25(OH)D < 27.5 nmol/L as being indicative of increased risk for rickets. Additionally, 25(OH)D > 125 nmol/L was considered possibly adversely high. Total vitamin D at 9-12 months (eight data collection days) included intake from diet and supplements. The mean ± SD of vitamin D intake was 8.8 ± 5.2 μg/day and serum 25(OH)D 98.1 ± 32.2 nmol/L (range 39.3-165.5). Ninety-two percent of infants were vitamin D sufficient and none at increased risk for rickets. The 26% infants using fortified products and supplements never/irregularly or in small amounts had lower 25(OH)D (76.8 ± 27.1 nmol/L) than the 22% using fortified products (100.0 ± 31.4 nmol/L), 18% using supplements (104.6 ± 37.0 nmol/L) and 33% using both (110.3 ± 26.6 nmol/L). Five of six infants with 25(OH)D < 50 nmol/L had no intake of supplements or fortified products from 0 to 12 months. Supplement use increased the odds of 25(OH)D > 125 nmol/L. Breastfeeding and season did not affect vitamin D status. The majority of infants were vitamin D sufficient. Our findings highlight the need for vitamin D supplements or fortified products all year round, regardless of breastfeeding.
    • Vitamin D Intake and Status in 6-Year-Old Icelandic Children Followed up from Infancy.

      Thorisdottir, Birna; Gunnarsdottir, Ingibjorg; Steingrimsdottir, Laufey; Palsson, Gestur I; Birgisdottir, Bryndis E; Thorsdottir, Inga; [ 1 ] Univ Iceland, Sch Hlth Sci, Fac Food Sci & Nutr, Unit Nutr Res, IS-101 Reykjavik, Iceland [ 2 ] Landspitali Univ Hosp, IS-101 Reykjavik, Iceland   Organization-Enhanced Name(s)      Landspitali National University Hospital [ 3 ] Landspitali Univ Hosp, Childrens Hosp, IS-101 Reykjavik, Iceland   Organization-Enhanced Name(s)      Landspitali National University Hospital (MDPI AG, 2016)
      High serum 25-hydroxyvitamin D (25(OH)D) levels have been observed in infants in Nordic countries, likely due to vitamin D supplement use. Internationally, little is known about tracking vitamin D status from infancy to childhood. Following up 1-year-old infants in our national longitudinal cohort, our aims were to study vitamin D intake and status in healthy 6-year-old Icelandic children (n = 139) and to track vitamin D status from one year of age. At six years, the mean 25(OH)D level was 56.5 nmol/L (SD 17.9) and 64% of children were vitamin D sufficient (25(OH)D ≥ 50 nmol/L). A logistic regression model adjusted for gender and breastfeeding showed that higher total vitamin D intake (Odds ratio (OR) = 1.27, 95% confidence interval (CI) = 1.08-1.49), blood samples collected in summer (OR = 8.88, 95% CI = 1.83-43.23) or autumn (OR = 5.64, 95% CI = 1.16-27.32) compared to winter/spring, and 25(OH)D at age one (OR = 1.02, 95% CI = 1.002-1.04) were independently associated with vitamin D sufficiency at age six. The correlation between 25(OH)D at age one and six was 0.34 (p = 0.003). Our findings suggest that vitamin D status in infancy, current vitamin D intake and season are predictors of vitamin D status in early school age children. Our finding of vitamin D status tracking from infancy to childhood provides motivation for further studies on tracking and its clinical significance.
    • Vitamin D status and association with gestational diabetes mellitus in a pregnant cohort in Iceland.

      Magnusdottir, Kristin S; Tryggvadottir, Ellen A; Magnusdottir, Ola K; Hrolfsdottir, Laufey; Halldorsson, Thorhallur I; Birgisdottir, Bryndis E; Hreidarsdottir, Ingibjorg T; Hardardottir, Hildur; Gunnarsdottir, Ingibjorg; 1Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland. 2Institution of Health Science Research, University of Akureyri and Akureyri Hospital, Akureyri, Iceland. 3Centre for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark. 4Department of Obstetrics and Gynecology, Landspitali University Hospital, Reykjavík, Iceland. 5Faculty of Medicine, University of Iceland, Reykjavík, Iceland. (Swedish Nutrition Foundation, 2021-03-23)
      Background: Vitamin D deficiency has been associated with an increased risk of gestational diabetes mellitus (GDM), one of the most common pregnancy complications. The vitamin D status has never previously been studied in pregnant women in Iceland. Objective: The aim of this research study was to evaluate the vitamin D status of an Icelandic cohort of pregnant women and the association between the vitamin D status and the GDM incidence. Design: Subjects included pregnant women (n = 938) who attended their first ultrasound appointment, during gestational weeks 11-14, between October 2017 and March 2018. The use of supplements containing vitamin D over the previous 3 months, height, pre-pregnancy weight, and social status were assessed using a questionnaire, and blood samples were drawn for analyzing the serum 25‑hydroxyvitamin D (25OHD) concentration. Information regarding the incidence of GDM later in pregnancy was collected from medical records. Results: The mean ± standard deviation of the serum 25OHD (S-25OHD) concentration in this cohort was 63±24 nmol/L. The proportion of women with an S-25OHD concentration of ≥ 50 nmol/L (which is considered adequate) was 70%, whereas 25% had concentrations between 30 and 49.9 nmol/L (insufficient) and 5% had concentrations < 30 nmol/L (deficient). The majority of women (n = 766, 82%) used supplements containing vitamin D on a daily basis. A gradual decrease in the proportion of women diagnosed with GDM was reported with increasing S-25OHD concentrations, going from 17.8% in the group with S-25OHD concentrations < 30 nmol/L to 12.8% in the group with S-25OHD concentrations ≥75 nmol/L; however, the association was not significant (P for trend = 0.11). Conclusion: Approximately one-third of this cohort had S-25OHD concentrations below adequate levels (< 50 nmol/L) during the first trimester of pregnancy, which may suggest that necessary action must be taken to increase their vitamin D levels. No clear association was observed between the vitamin D status and GDM in this study. Keywords: cod liver oil; gestational diabetes mellitus; nutritional status; pregnancy; supplements; vitamin D.
    • Young overweight and obese women with lower circulating osteocalcin concentrations exhibit higher insulin resistance and concentrations of C-reactive protein.

      Lucey, Alice J; Paschos, Georgios K; Thorsdottir, Inga; Martínéz, J Alfredo; Cashman, Kevin D; Kiely, Máireád; Natl Univ Ireland Univ Coll Cork, Sch Food & Nutr Sci, Cork, Ireland, Univ Iceland, Unit Nutr Res, Reykjavik, Iceland, Landspitali Univ Hosp, Reykjavik, Iceland, Univ Navarra, Dept Physiol & Nutr, E-31080 Pamplona, Spain, Natl Univ Ireland Univ Coll Cork, Sch Med, Cork, Ireland (Pergamon Elsevier Science, 2013-01)
      The role of the skeleton in the regulation of energy metabolism in humans is not clear. This study investigates the hypothesis that biomarkers of bone turnover are associated with indices of glucose homeostasis and systemic inflammation in young adults. A cross-sectional study investigating the relationships between biomarkers of bone turnover (serum total and uncarboxylated osteocalcin, bone-specific alkaline phosphatase, C-telopeptide of type I collagen, urinary N-telopeptide of type I collagen) and glucose metabolism (fasting plasma glucose [FPG], insulin, insulin resistance [homeostatic model assessment of insulin resistance]), systemic inflammation (high-sensitivity C-reactive protein [hsCRP] and interleukin-6), adipokines (leptin and adiponectin), and body composition was conducted in 268 young, nondiabetic overweight and obese adults aged 20 to 40 years (116 men, 152 women; body mass index, 27.5-32.5 kg/m(2)). Data on diet, physical activity, serum 25-hydroxyvitamin D, and parathyroid hormone were also collected. In women, there was a stepwise increase in lean body mass (P < .05) and a decrease in serum hsCRP (P < .001) across tertiles of total osteocalcin. Multiple linear regression analysis showed significant inverse associations between total osteocalcin and FPG (β = -0.350; P = .016; 95% confidence interval [CI], -0.35 to -0.04), insulin (β = -0.455; P = .002; 95% CI, -1.9 to -0.46), and homeostatic model assessment of insulin resistance (β = -0.508; P = .001; 95% CI, -10.93 to -3.17) in women with total osteocalcin concentrations below the group median. Men in the lowest tertile of uncarboxylated osteocalcin had twice the concentration of hsCRP than did other men (P = .05). In this sample, women with less lean body mass had lower circulating total osteocalcin concentrations and exhibited higher FPG, insulin resistance, and hsCRP compared with their similarly sized counterparts, suggesting that associations between osteocalcin and systemic inflammation, glucose homeostasis, and insulin resistance may be influenced by differences in sex and body composition.