Linnea Bärebring

Preeclampsia and Blood Pressure Trajectory during Pregnancy in Relation to Vitamin D Status

Every tenth pregnancy is affected by hypertension, one of the most common complications and leading causes of maternal death worldwide. Hypertensive disorders in pregnancy include pregnancy-induced hypertension and preeclampsia. The pathophysiology of the development of hypertension in pregnancy is unknown, but studies suggest an association with vitamin D status, measured as 25-hydroxyvitamin D (25(OH)D). The aim of this study was to investigate the association between gestational 25(OH)D concentration and preeclampsia, pregnancy-induced hypertension and blood pressure trajectory. This cohort study included 2000 women. Blood was collected at the first (T1) and third (T3) trimester (mean gestational weeks 10.8 and 33.4). Blood pressure at gestational weeks 10, 25, 32 and 37 as well as symptoms of preeclampsia and pregnancy-induced hypertension were retrieved from medical records. Serum 25(OH)D concentrations (LC-MS/MS) in T1 was not significantly associated with preeclampsia. However, both 25(OH)D in T3 and change in 25(OH)D from T1 to T3 were significantly and negatively associated with preeclampsia. Women with a change in 25(OH)D concentration of ≥30 nmol/L had an odds ratio of 0.22 (p = 0.002) for preeclampsia. T1 25(OH)D was positively related to T1 systolic (β = 0.03, p = 0.022) and T1 diastolic blood pressure (β = 0.02, p = 0.016), and to systolic (β = 0.02, p = 0.02) blood pressure trajectory during pregnancy, in adjusted analyses. There was no association between 25(OH)D and pregnancy-induced hypertension in adjusted analysis. In conclusion, an increase in 25(OH)D concentration during pregnancy of at least 30 nmol/L, regardless of vitamin D status in T1, was associated with a lower odds ratio for preeclampsia. Vitamin D status was significantly and positively associated with T1 blood pressure and gestational systolic blood pressure trajectory but not with pregnancy-induced hypertension.

Vitamin D Status during Pregnancy in a Multi-Ethnic Population-Representative Swedish Cohort

There is currently little information on changes in vitamin D status during pregnancy and its predictors. The aim was to study the determinants of change in vitamin D status during pregnancy and of vitamin D deficiency (<30 nmol/L) in early pregnancy. Blood was drawn in the first (T1) and third trimester (T3). Serum 25-hydroxyvitamin D (25(OH)D) (N = 1985) was analysed by liquid chromatography tandem-mass spectrometry. Season-corrected 25(OH)D was calculated by fitting cosine functions to the data. Mean (standard deviation) 25(OH)D was 64.5(24.5) nmol/L at T1 and 74.6(34.4) at T3. Mean age was 31.3(4.9) years, mean body mass index (BMI) was 24.5(4.2) kg/m2 and 74% of the women were born in Sweden. Vitamin D deficiency was common among women born in Africa (51%) and Asia (46%) and prevalent in 10% of the whole cohort. Determinants of vitamin D deficiency at T1 were of non-North European origin, and had less sun exposure, lower vitamin D intake and lower age. Season-corrected 25(OH)D increased by 11(23) nmol/L from T1 to T3. The determinants of season-corrected change in 25(OH)D were origin, sun-seeking behaviour, clothing style, dietary vitamin D intake, vitamin D supplementation and recent travel <35° N. In conclusion, season-corrected 25(OH)D concentration increased during pregnancy and depended partly on lifestyle factors. The overall prevalence of vitamin D deficiency was low but common among women born in Africa and Asia. Among them, the determinants of both vitamin D deficiency and change in season-corrected vitamin D status were fewer, indicating a smaller effect of sun exposure.

Determinants of changes in vitamin D status postpartum in Swedish women

Low vitamin D status has been associated with unfavourable health outcomes. Postpartum, it is speculated that maternal vitamin D status decreases due to transfer of vitamin D from mother to child through breast milk. A few studies have investigated changes in maternal vitamin D postpartum and possible determinants. Thus, the aims of the present study were to determine changes in serum concentrations of 25-hydroxyvitamin D (25(OH)D) between 2 weeks and 12 months postpartum in Swedish women and to evaluate lactation and other determinants for changes in 25(OH)D concentration postpartum. In total, seventy-eight women were studied at 2 weeks, 4 months and 12 months postpartum. Data collection included measurements of weight and height as well as information about lactation, sun exposure, use of oestrogen contraceptives and physical activity level. Blood samples were collected and serum 25(OH)D levels were analysed using liquid chromatography-tandem MS. Dietary intake of vitamin D was recorded using 4-d food diaries. For all the women studied, mean serum 25(OH)D did not change between 2 weeks and 12 months postpartum (67 (SD 23) v. 67 (SD 19) nmol/l). No association was found between lactation and changes in serum 25(OH)D concentration postpartum. Significant determinants for postpartum changes in 25(OH)D concentration were use of vitamin D supplements (P=0·003), use of oestrogen contraceptives (P=0·013) and season (P=0·005). In conclusion, no changes were observed in 25(OH)D concentrations during the 1st year postpartum in these women and no association was found between lactation and changes in 25(OH)D concentration postpartum. The main determinants for the variation in changes in 25(OH)D concentrations postpartum were use of vitamin D supplements, use of oestrogen contraceptives and season.

Validation of Dietary Vitamin D Intake from Two Food Frequency Questionnaires, Using Food Records and the Biomarker 25-Hydroxyvitamin D among Pregnant Women

Our objective was to validate vitamin D intake from a short vitamin D questionnaire (VDQ) and a longer online food frequency questionnaire (FFQ) against a food record and 25-hydroxyvitamin D (25OHD) as a biomarker of vitamin D status, among pregnant women in Sweden. The number of women included was 1125 with VDQ, FFQ and 25OHD, and of those, 64 also completed the food record. Median vitamin D intakes were 3.9 µg by VDQ (p < 0.001), and 5.3 µg by FFQ (p = 0.89), compared to 5.0 µg by food record. Correlations between vitamin D intake from food record and VDQ (rho = 0.51, p < 0.001) or FFQ (rho = 0.49, p < 0.001) were similar. The VDQ and FFQ also had a similar ability to rank the individuals according to vitamin D intake. However, only vitamin D intake from the VDQ was significantly associated with vitamin D status as assessed by 25OHD. The validation coefficient for the VDQ was 0.68 and 0.75 for the FFQ. In conclusion, assessing dietary vitamin D intake is challenging, regardless of the dietary assessment method. The VDQ, that includes only four food items, is a valid, simple and useful tool in assessing vitamin D intake of pregnant women in Sweden, while imposing a minimal burden on women and researchers.

Avoiding maternal vitamin D deficiency may lower blood glucose in pregnancy

BACKGROUND Vitamin D status is hypothesised to play a role in gestational glucose control. No studies to date have examined vitamin D in relation to changes in blood glucose in pregnancy. Thus, the aim was to examine if vitamin D in early pregnancy and vitamin D trajectory associate with blood glucose trajectory over pregnancy in a Swedish cohort. We also investigated the relation between maternal vitamin D status and excessive fetal growth. METHODS In 2013-2014, pregnant women were recruited to the GraviD cohort study when registering at the antenatal clinics in south-west Sweden. In the present analysis, 1928 women were included. Women with preexisting diabetes and multifetal pregnancy were excluded. Random blood glucose was assessed according to routine practice, in first trimester (T1, gestational week 4-16), second trimester (T2, gestational week 17-27), early (T3a, gestational week 28-35) and late third trimester (T3b, gestational week 36-41). In T1 and T3a, serum 25-hydroxyvitamim D (25OHD) was analyzed by liquid chromatography tandem mass spectrometry. Large for gestational age (LGA), as a proxy of excessive fetal growth, was defined as body weight at birth above 2 standard deviations of the gender specific population mean. Adjusted linear regression, linear mixed models analysis and logistic regression analysis were used to study 25OHD in relation to T1 blood glucose, glucose trajectory and LGA, respectively. RESULTS Mean blood glucose increased during pregnancy (5.21 mmol/L in T1, 5.27 mmol/L in T2, 5.31 mmol/L in T3a and 5.34 mmol/L in T3b; p = 0.003). In T1, 25OHD was negatively associated with blood glucose, i.e. 25OHD ≥ 30 nmol/L was associated with 0.25-0.35 mmol/L lower glucose. T1 25OHD was also negatively associated with blood glucose trajectory. Higher T3 25OHD was associated with higher odds of LGA (p = 0.032). CONCLUSION Avoiding maternal vitamin D deficiency in early pregnancy is associated with lower blood glucose in early pregnancy and throughout pregnancy. Higher 25OHD in late pregnancy was associated with higher odds of LGA at birth.

Poor Dietary Quality Is Associated with Increased Inflammation in Swedish Patients with Rheumatoid Arthritis

The aim was to study whether dietary quality was associated with disease activity and inflammation among patients with rheumatoid arthritis (RA). This cross-sectional analysis included 66 Swedish participants, who each completed a food frequency questionnaire (FFQ) at screening. Food intake was scored by a dietary quality index created by the Swedish National Food Agency. Disease activity was measured as Disease Activity Score 28 (DAS28), based on erythrocyte sedimentation rate (ESR), a patient administered visual analogue scale of perceived global health and the number of tender and swollen joints out of 28 examined. Inflammation was measured as ESR and C-reactive protein (hs-CRP). Associations between dietary quality, disease activity and inflammation were evaluated using multivariable linear regression analysis. High dietary quality (high intake of fish, shellfish, whole grain, fruit and vegetables and low intake of sausages and sweets) was not related to DAS28 (B = −0.02, p = 0.787). However, dietary quality was significantly negatively associated with hs-CRP (B = −0.6, p = 0.044) and ESR (B = −2.4, p = 0.002) after adjusting for body mass index, age, education, smoking and gender. Both hs-CRP and ESR decreased with increasing dietary quality. In conclusion, among patients with RA, high dietary quality was associated with reduced inflammation but not with disease activity.