Moira S Hutchinson

University Hospital of North Norway, Tromsø, Troms, Norway

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Publications (9)27.24 Total impact

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    ABSTRACT: In observational studies, low serum 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with insulin resistance and other risk factors for cardiovascular disease.RESEARCH DESIGN AND METHODS: We present 1-year data from an ongoing 5-year trial in 511 individuals with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) randomly assigned to 20,000 IU/week vitamin D3 or placebo. An oral glucose tolerance test was performed at baseline and after 1 year.RESULTS: Mean baseline serum 25(OH)D was 59.9 nmol/L and 61.1 nmol/L in the vitamin D and placebo groups, respectively, and increased by 45.8 nmol/L and 3.4 nmol/L, respectively. With adjustment for baseline concentrations, no differences in measures of glucose metabolism, insulin secretion or sensitivity, blood pressure, or hs-CRP were found after 1 year. There was a slight, but significant decrease in total and LDL cholesterol in the vitamin D group compared with the placebo group, but as there was also a decrease in HDL cholesterol, the change in the total/HDL cholesterol ratio did not differ significantly. Only analyzing subjects with 25(OH)D <50 nmol/L did not change the results.CONCLUSIONS: This study shows that vitamin D supplementation does not improve glycemic indices, blood pressure, or lipid status in subjects with IFG and/or IGT.
    Diabetes care. 06/2014;
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    ABSTRACT: Cross-sectional studies indicate a positive relation between serum 25-hydroxyvitamin D [25(OH)D] and testosterone. It is not known if this relation is causal, which in theory could be in both directions. A cross-sectional population based study was designed with pooled data from 3 vitamin D randomized clinical trials (RCTs) performed in Tromsø with weight reduction, insulin sensitivity, and depression scores as endpoints, and one testosterone RCT in subjects with low serum testosterone (<11.0 nmol/l) and with body composition as endpoint. Serum 25(OH)D and androgens were measured in 893 males in the cross-sectional part, at baseline and after 6-12 months of supplementation with vitamin D 20 000 IU-40 000 IU per week vs. placebo in the vitamin D RCTs (n=282), and at baseline and after one year treatment with testosterone undecanoate 1 000 mg or placebo injections (at baseline and after 6, 16, 28, and 40 weeks) in the testosterone RCT (n=37). In the cross-sectional study, serum 25(OH)D was found to be a significant and positive predictor of serum testosterone. In the vitamin D RCTs, no significant effect on serum total or free testosterone levels was seen, and in the testosterone RCT no significant effect on serum 25(OH)D was seen. This was unchanged in sub-analyses in subjects with low serum 25(OH)D (or testosterone) levels. In conclusion, in subjects without significant vitamin D deficiency, there is no increase in serum testosterone after high dose vitamin D supplementation. Similarly, in subjects with moderately low serum testosterone levels, substitution with testosterone does not increase serum 25(OH)D.
    Hormone and Metabolic Research 05/2013; · 2.15 Impact Factor
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    ABSTRACT: AIMS: To compare depressive symptoms in participants with low and high serum 25-hydroxyvitamin D (25(OH)D) levels and to examine whether supplementation with vitamin D(3) would improve symptoms in those with low serum 25(OH)D levels. METHOD: Participants with low 25(OH)D levels were randomised to either placebo or 40 000 IU vitamin D(3) per week for 6 months. Individuals with high serum 25(OH)D levels were used as nested controls. Depressive symptoms were evaluated with the Beck Depression Inventory, Hospital Anxiety and Depression Scale, Seasonal Pattern Assessment Scale and Montgomery-Åsberg Depression Rating Scale. The study was registered at (NCT00960232). RESULTS: Participants with low 25(OH)D levels (n = 230) at baseline were more depressed (P<0.05) than participants with high 25(OH)D levels (n = 114). In the intervention study no significant effect of high-dose vitamin D was found on depressive symptom scores when compared with placebo. CONCLUSIONS: Low levels of serum 25(OH)D are associated with depressive symptoms, but no effect was found with vitamin D supplementation.
    The British journal of psychiatry: the journal of mental science 07/2012; · 6.62 Impact Factor
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    ABSTRACT: Vitamin D deficiency has been associated with a number of diseases, including influenza. Whether or not this reflects a causal relationship is unknown. We therefore wanted to examine if supplementation with vitamin D would affect the incidence and severity of influenza-like disease. Questionnaires on influenza were sent to subjects participating in ongoing placebo-controlled intervention studies with vitamin D supplementation, up until the end of April 2010. Five hundred and sixty-nine subjects from 10 different clinical trials were included in the study, of whom 289 were randomized to receive vitamin D (1111-6800 IU/day) and 280 to receive placebo. Influenza-like disease during the previous fall/winter was reported in 38 subjects in the vitamin D group and 42 in the placebo group (non-significant), of whom 25 and 26 subjects, respectively, fulfilled our clinical criteria for influenza. In these latter subjects, the duration of illness was significantly longer among those in the vitamin D group than among those in the placebo group (median 7 (range 2-60) days vs median 4 (range 2-18) days; p = 0.007). However, this difference was not statistically significant if all 38 (vitamin D) and 42 (placebo) subjects who reported symptoms were included. Our results do not support the hypothesis that high doses of vitamin D supplementation will have a pronounced effect on influenza-like disease in populations not targeted for high influenza risk.
    Scandinavian Journal of Infectious Diseases 02/2012; 44(2):126-32. · 1.71 Impact Factor
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    ABSTRACT: Background Haemoglobin A1c 6.5 % has recently been recommended by the World Health Organization (WHO) and the American Diabetes Association (ADA) as an alternative diagnostic criterion for diabetes mellitus (DM). Aim To evaluate HbA1c as an alternative to oral glucose tolerance test (OGTT) for diagnosis of DM and pre-diabetes and to find the optimal HbA1c cut off points for DM and pre-diabetes in our population. Subjects and Methods The subjects were recruited from the Tromsø Study, performed for the sixth time in 2007-2008 with 12 984 participants. All subjects with HbA1c in the range 5.8 - 6.9 % and a random sample of subjects with levels 5.3 - 5.7 % were invited to an OGTT. Results Among 3476 subjects who completed the OGTT, 199 were diagnosed with DM. The best sensitivity (69.8 %) and specificity (81.8 %) were found at HbA1c 6.2 %. For HbA1c 6.5 % we found a sensitivity of 34.7 % and specificity 97.1 %. The best cut off points for impaired fasting glucose (n=314) and impaired glucose tolerance (n=404) were found at HbA1c 5.9 % and 6.0 %, respectively. Pre-diabetes detected only by OGTT was associated with worse metabolic characteristics than pre-diabetes detected only by HbA1c. Conclusions The optimum HbA1c cut off point for DM in our population was lower than that proposed by WHO and ADA. To establish more precisely the HbA1c levels predictive of micro and macro-vascular complications long term prospective studies are needed. Population specific optimum cut off points may be necessary.
    Journal of endocrinological investigation 12/2011; · 1.65 Impact Factor
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    ABSTRACT: The relationships between vitamin D concentrations, hyperglycemia, and insulin resistance remain uncertain. During 2008 - 2010, an oral glucose tolerance test was performed in 3520 subjects from Tromsø, Norway. Serum 25-hydroxyvitamin D [25(OH)D] was measured in 1193 subjects with normal glucose tolerance, in 304 with isolated impaired fasting glucose, in 254 with isolated impaired glucose tolerance, in 139 with a combination of the two, and in 194 subjects with type 2 diabetes. Serum 25(OH)D did not differ between subjects with isolated impaired fasting glucose or impaired glucose tolerance, but was lower in all groups of deranged glucose metabolism as compared with normal subjects. These differences could not be explained by differences in intakes of vitamin D from cod liver oil or other supplements and remained statistically significant after adjustment for gender, age, body mass index, physical activity score, and month of examination. When the cohort was divided according to serum 25(OH)D quartiles, there was an improvement in all measures of glucose metabolism (fasting and 2-hour plasma glucose, serum insulin, HbA(1c)) and estimates of insulin resistance (QUICKI , HOMA-IR, ISI(0.120)) with increasing serum 25(OH)D quartile. However, interventional studies are needed to prove a causal relationship between vitamin D and glucose metabolism.
    International Journal for Vitamin and Nutrition Research 09/2011; 81(5):317-27. · 1.27 Impact Factor
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    ABSTRACT: Animal and human studies have shown an association between serum 25-hydroxyvitamin D (25(OH)D) level and insulin secretion and sensitivity. Accordingly, an association between 25(OH)D and glycated haemoglobin (HbA(1c)) is to be expected, and this was tested for in the present study. The Tromsø Study is a longitudinal population-based study initiated in 1974. In the sixth Tromsø Study conducted in 2007-2008, 12,984 subjects aged 30-87 years attended. After exclusion of current smokers and subjects with diabetes, the dataset consisted of 8643 subjects available for the present analyses. The correlation between serum 25(OH)D and HbA(1c) was -0.07 (p < 0.001). This association remained significant in a multiple linear regression model after adjustment for covariates gender, age, month of blood sampling, body mass index (BMI), physical activity score, serum triglycerides (TG), serum calcium and haemoglobin, and persisted across categories of gender, age, BMI and TG. The association appears to be most pronounced in the oldest, the obese and in those with the highest TG levels. Seasonal variation was found both for serum 25(OH)D and HbA(1c) with highest serum 25(OH)D levels and lowest HbA(1c) levels during summer months. In conclusion, there is a significant inverse association between serum 25(OH)D and HbA(1c) after adjustment for known confounders. The association is most pronounced in subjects with risk factors for glucose intolerance/type 2 diabetes. In a sub-analysis on subjects with diabetes the association between serum 25(OH)D and HbA(1c) appeared even stronger with a difference in HbA(1c) of 0.48 % between the highest and lowest serum 25(OH)D quartiles.
    Scandinavian journal of clinical and laboratory investigation 04/2011; 71(5):399-406. · 1.38 Impact Factor
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    ABSTRACT: Low serum 25-hydroxyvitamin D (25(OH)D) levels are associated with risk factors for cardiovascular disease, and they also appear to predict later development of type 2 diabetes, cancer, and an increased mortality rate. These predictions are all based on a single 25(OH)D measurement, but so far there are no known reports on tracking of serum 25(OH)D levels. In the present Norwegian study, serum 25(OH)D levels were measured 1) in 2,668 subjects in the 1994 and 2008 Tromsø surveys and 2) every third month for 1 year in 94 subjects randomly assigned to placebo in a vitamin D intervention study. There was a marked seasonal variation in 25(OH)D, and, depending on the method of adjusting for season, the correlation coefficient between serum 25(OH)D measurements from 1994 and 2008 ranged from 0.42 to 0.52. In the 1-year intervention study, the correlation between baseline and 12-month values was 0.80. Apart from the effect of season, changes in weight, intake of vitamin D, and physical activity were related to change in serum 25(OH)D levels. Tracking of serum 25(OH)D appears similar to that for blood pressure and serum lipids, and it provides some support for the use of a single 25(OH)D measurement to predict future health outcomes.
    American journal of epidemiology 03/2010; 171(8):903-8. · 5.59 Impact Factor
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    ABSTRACT: Vitamin D receptors have been detected in vascular smooth muscle cells, and 1,25-dihydroxyvitamin D inhibits the renin mRNA expression. Epidemiological studies show an inverse relation between serum 25-hydoxyvitamin D levels and blood pressure, and low serum 25-hydoxyvitamin D levels are reported to be predictors of future development of hypertension. This may indicate an important role for vitamin D in blood pressure regulation. In the present study, 25-hydoxyvitamin D was measured in sera collected in 1994 from 4125 subjects who did not use blood pressure medication, and thereafter measurement was repeated in 2008 for 2385 of these subjects. In sera from 1994 there was a significant decrease in age, body mass index, and systolic blood pressure and a significant increase in physical activity score across increasing 25-hydoxyvitamin D quartiles. After adjusting for sex, age, body mass index, and physical activity, the difference in systolic blood pressure between the lowest and highest serum 25-hydoxyvitamin D quartiles was 3.6 mm Hg. After adjustment for confounders, serum 25-hydoxyvitamin D from 1994 did not predict future hypertension or increase in blood pressure, nor was there any significant association between change in serum 25-hydoxyvitamin D from 1994 to 2008 and change in blood pressure. Our results do not support a causal role for vitamin D in blood pressure regulation, and large randomized clinical trials, preferably including subjects with hypertension and/or low serum 25-hydoxyvitamin D levels, are greatly needed to clarify whether vitamin D supplementation affects the blood pressure.
    Hypertension 03/2010; 55(3):792-8. · 6.87 Impact Factor