ObjectivesTo estimate the prevalence of vitamin D deficiency (25(OH)D) <50 nmol/L among recently arrived immigrants from Africa and Asia in Oslo, and to explore 25(OH)D levels according to origin, gender and age.DesignA cross-sectional study.SettingPrimary healthcare unit in Oslo, Norway, offering family immigrants, asylum seekers, United Nations (UN) refugees or individuals granted asylum a free medical examination on arrival.ParticipantsAll individuals from African and Asian countries (n=591) referred to the Centre of Migrant Health, Health Agency, Oslo, Norway in 2010, estimated to cover 60% of the targeted population.Results25(OH)D <50 nmol/L was very prevalent in immigrants from the Middle East (81% (95% CI 75.4% to 86.6%)), South Sahara Africa (73% (CI 67.5% to 78.5%)) and South Asia (75% (CI 64.0% to 86.0%)), in contrast to East Asians (24% (CI 12.6% to 35.4%)), p<0.001 for differences. The prevalence of 25(OH)D<25 nmol/L was lower but followed the same pattern (Middle East: 38% (CI 31.1% to 45.0%), South Sahara Africa: 24% (CI 18.7% to 29.3%) and South Asia: 35% (CI 22.9% to 47.1%), although it was not observed in East Asians (p<0.001 for differences)). The ethnic differences persisted after adjusting for the duration of residence, seasonality and residence status in multiple linear regression analyses. Female adolescents from South Asia, the Middle East and South Sahara Africa had the lowest levels of 25(OH)D. Further, country-specific median levels of 25(OH)D were low (24–38 nmol/L) among groups from Somalia, Eritrea, Afghanistan and Iraq, the countries with the largest number of immigrants in our study.ConclusionsThe majority of recently settled immigrant groups from the Middle East, South Asia and Africa had 25(OH)D <50 nmol/L, in contrast to East Asians. Female adolescents from these regions had the lowest levels of 25(OH)D.

BackgroundTo investigate ethnic differences in vitamin D levels during pregnancy, assess risk factors for vitamin D deficiency and explore the effect of vitamin D supplementation in women with deficiency in early pregnancy.MethodsThis is a population-based, multiethnic cohort study of pregnant women attending Child Health Clinics for antenatal care in Oslo, Norway. Serum-25-hydroxyvitamin D [25(OH)D] was measured in 748 pregnant women (59 % ethnic minorities) at gestational weeks (GW) 15 (SD:3.6) and 28 (1.4). Women with 25(OH)D <37 nmol/L at GW 15 were for ethical reasons recommended vitamin D3 supplementation. Main outcome measure was 25(OH)D, and linear regression models were performed.ResultsSevere deficiency (25(OH)D <25 nmol/L) was found at GW 15 in 45 % of women from South Asia, 40 % from the Middle East and 26 % from Sub-Saharan Africa, compared to 2.5 % in women from East Asia and 1.3 % of women from Western Europe. Women from South Asia, the Middle East and Sub-Saharan Africa had mean values that were −28 (95 % CI:-33, −23), −24 (−29, −18) and −20 (−27, −13) nmol/L lower than in Western women, respectively. Ethnicity, education, season and intake of vitamin D were independently associated with 25(OH)D. At GW 28, the mean 25(OH)D had increased from 23 (SD:7.8) to 47 (27) nmol/L (p < 0.01) in women who were recommended vitamin D supplementation, with small or no change in women with sufficient vitamin D levels at baseline.ConclusionsVitamin D deficiency was prevalent among South Asian, Middle Eastern and African women. The serum levels of 25(OH)D increased significantly from GW 15 to 28 in vitamin D deficient women who received a recommendation for supplementation. This recommendation of vitamin D supplementation increased vitamin D levels in deficient women.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-016-0796-0) contains supplementary material, which is available to authorized users.

We investigated associations between serum 25-hydroxyvitamin D (25(OH)D) in pregnancy and birth weight and other neonatal anthropometric measures. The present study was a population-based, multiethnic cohort study of 719 pregnant women (59 % ethnic minorities) in Oslo, Norway, delivering a singleton neonate at term and with birth weight measurements. In a representative sample, anthropometric measurements were taken. Maternal 25(OH)D was measured at gestational weeks 15 and 28. Women with 25(OH)D <37 nmol/l were recommended vitamin D3 supplementation. Separate linear regression analyses were performed to model the associations between 25(OH)D and each of the outcomes: birth weight, crown-heel length, head circumference, abdominal circumference, sum of skinfolds, mid-upper arm circumference and ponderal index. In early pregnancy, 51 % of the women were vitamin D deficient (25(OH)D<50 nmol/l). In univariate analyses and in models adjusting for maternal age, parity, education, prepregnancy BMI, season, gestational age and neonate sex, maternal 25(OH)D was significantly associated with birth weight, head circumference, abdominal circumference and ponderal index (P<0·05 for all), when used as a continuous variable and categorised (consistently low, consistently high, increasing and decreasing level). However, after adjusting for ethnicity, 25(OH)D was no longer associated with any of the outcomes. Sex-specific associations for abdominal circumference and sum of skinfolds were found (P for interaction<0·05). In conclusion, in a multiethnic cohort of pregnant women with high prevalence of vitamin D deficiency, we found no independent relation between maternal vitamin D levels and any of the neonatal anthropometric measures, and the strong association between ethnicity and neonatal outcomes was not affected by maternal vitamin D status.

Context:Autoimmune thyroid disorders have been linked to vitamin D deficiency, but an effect of vitamin D supplementation is not established.Objective:Our objective was to test whether vitamin D compared with placebo could reduce thyroid autoantibodies.Design:Predefined additional analyses from a randomized, double-blind, placebo-controlled trial.Setting:The study was conducted in different community centers in Oslo, Norway.Participants:A total of 251 presumed healthy men and women, aged 18 to 50 years, with backgrounds from South Asia, the Middle East, and Africa were included.Intervention:Daily supplementation with 25 µg (1000 IU) vitamin D3, 10 µg (400 IU) vitamin D3, or placebo for 16 weeks.Outcome Measure:Difference in preintervention and postintervention antithyroid peroxidase antibody (TPOAb) levels. Additional outcomes were differences in thyroid-stimulating hormone (TSH) and free fraction of thyroxine (fT4).Results:There were no differences in change after 16 weeks on TPOAb (27 kU/L; 95% CI, −17 to 72; P = 0.23), TSH (−0.10 mU/L; 95% CI, −0.54 to 0.34; P = 0.65), or fT4 (0.09 pmol/L; 95% CI, −0.37 to 0.55; P = 0.70) between those receiving vitamin D supplementation or placebo. Mean serum 25(OH)D3 increased from 26 to 49 nmol/L in the combined supplementation group, but there was no change in the placebo group.Conclusion:Vitamin D3 supplementation, 25 µg or 10 µg, for 16 weeks compared with placebo did not affect TPOAb level in this randomized, double-blind study among participants with backgrounds from South Asia, the Middle East, and Africa who had low vitamin D levels at baseline.

BackgroundWhich blood-based indicator best reflects the iron status in pregnant women is unclear. Better assessments of iron status in today's multiethnic populations are needed to optimize treatment and clinical recommendations.ObjectivesWe aimed to determine the prevalence of anemia (hemoglobin <11.0 g/dL in first and <10.5 g/dL in second trimester) and iron deficiency (ID) by the iron indicators serum ferritin <15 µg/L, serum soluble transferrin receptor (sTfR) >4.4 mg/L, and calculated total body iron <0 mg/kg, and their associations with ethnicity.MethodsThis was a population-based cross-sectional study from primary antenatal care of 792 healthy women in early pregnancy in Oslo, Norway. We categorized the women into 6 ethnic groups: Western European, South Asian, Middle Eastern, Sub-Saharan African, East Asian, and Eastern European.ResultsAnemia was found in 5.9% of women (Western Europeans: 1.8%; non-Western: 0–14%, P < 0.05). ID from ferritin was found in 33% (Western Europeans: 15%; non-Western: 27–55%, P < 0.05). ID from sTfR was found in 6.5% (Western Europeans: 0.3%; non-Western: 0–20%, P < 0.01). Calculated total body iron indicated ID in 11% (Western Europeans: 0.6%, non-Western: 7.0–28%, P < 0.01). The prevalence of ID was significantly higher by all measures in South Asian, Sub-Saharan African, and Middle Eastern than in Western European women, and the ethnic differences persisted after adjusting for confounders. South Asians, Sub-Saharan Africans, and Middle Easterners had lower iron concentrations by all measures for all hemoglobin intervals. Anemia related to ID varied from 35% (sTfR) to 46% (total body iron) and 72% (ferritin) depending on the iron indicator used.ConclusionsWomen at the highest risk of ID and anemia were of South Asian, Middle Eastern, and Sub-Saharan African origin. The prevalence of ID differed considerably depending on the iron indicator used.