[Prevalence and Trends in Prepregnancy Overweight and Obesity in Northern Iceland 2004-2022]

INTRODUCTION

Prepregnancy overweight and obesity is an increasing public health issue worldwide, including Iceland, and has been associated with higher risk of adverse maternal and birth outcomes. The aim of this study was to investigate trends in prepregnancy weight amongst women in North Iceland from 2004 to 2022, and the prevalence of overweight and obesity in this population.

MATERIAL AND METHODS

This retrospective cross-sectional study included all women who gave birth at Akureyri Hospital in North Iceland between 2004 and 2022 (N = 7410). Information on age, parity, height, and prepregnancy weight was obtained from an electronic labour audit database. Body mass index (BMI) was calculated from self-reported height and weight, and the median BMI and proportions in each of the six BMI categories were calculated for four time periods.

RESULTS

Median BMI increased significantly from 24.5 kg/m2 in 2004-2008 to 26.2 kg/m2 in 2019-2022. On average, BMI increased by 0.15 kg/m2 with each passing year (p<0.001). The prevalence of normal weight decreased from 53% to 40% and the entire BMI distribution shifted towards a higher BMI. The proportion of women in obesity class I (BMI 30.0 - 34.9) increased from 12.8% to 17.3%, the proportion of women in obesity class II (BMI 35.0 - 39.9) doubled (3.7% to 8.1%) and tripled in obesity class III (BMI ≥ 40.0; 1.6% to 4.8%).

CONCLUSION

Prepregnancy weight of women in Northern Iceland has gradually increased over the last 19 years and 30% of pregnant women are now classified as obese. Further studies on the subsequent effects on maternal and birth outcomes are needed, with a focus on strategies to decrease adverse effects and reverse this trend.

Early pregnancy plasma fatty acid profiles of women later diagnosed with gestational diabetes

INTRODUCTION

Fatty acid (FA) concentrations have previously been associated with gestational diabetes mellitus (GDM). However, few studies on GDM have examined FA profiles in early pregnancy or before diagnosis. This study aimed to compare early pregnancy plasma FA profiles of women with and without GDM diagnoses as well as their reported dietary consumption.

RESEARCH DESIGN AND METHODS

The subjects comprised 853 women from the prospective study: Pregnant Women in Iceland II (PREWICE II), attending their 11-14 weeks ultrasound appointment in 2017-2018. During the visit, blood samples were collected for plasma FA analysis, and dietary habits were assessed using a short food frequency questionnaire. Information on GDM diagnoses was then later extracted from medical records. Differences in FA profile between GDM cases and non-cases were evaluated using the Mann-Whitney U test.

RESULTS

GDM was diagnosed in 127 women (14.9%). Concentrations of saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids (PUFA) n-6, PUFA n-3 and total FA were higher in the women who later developed GDM compared with those who did not (p≤0.05). The medians for total FA were 2898 μg/mL for the women with GDM and 2681 μg/mL for those without GDM. Mean adjusted difference for total FA between the groups was 133 μg/mL (95% CI 33 to 233). Similar results were observed in prepregnancy normal-weight women and overweight women/women with obesity. Overall diet quality in early pregnancy appeared to be lower among the women later diagnosed with GDM.

CONCLUSION

We found that plasma FA profiles in early pregnancy were different for women later diagnosed with GDM compared with those who were not, independent of the women's body mass index.

Higher Alkylresorcinol Concentrations, a Consequence of Whole-Grain Intake, are Inversely Associated with Gestational Diabetes Mellitus in Iceland

BACKGROUND

A diet rich in whole grains may provide benefits for pregnant women due to whole grains' high nutritional value and dietary fiber content.

OBJECTIVES

To study the associations of whole-grain consumption, as well as the plasma alkylresorcinol concentration, a whole-grain consumption biomarker, in early pregnancy with gestational diabetes mellitus (GDM) diagnoses.

METHODS

Subjects were women from the prospective study Pregnant Women in Iceland II (PREWICE II; n = 853) who attended their ultrasound appointment in gestational weeks 11-14 during the period from October 2017 to March 2018. During that visit, whole-grain consumption was estimated using a diet screening questionnaire, and blood samples were collected for analysis of plasma alkylresorcinols (ARs). Information on GDM diagnoses was later extracted from medical records. Multivariate log-binomial regression was used to evaluate the association of dietary whole-grain and AR concentrations with GDM.

RESULTS

In total, 14.9% of the women adhered to the national food-based dietary guidelines (n = 127), which recommend 2 portions of whole grains daily. GDM was diagnosed in 127 women (14.9%). The frequency of whole-grain consumption was lower in women who were later diagnosed with GDM compared to the women without GDM (median, 5 times/week vs. 6 times/week, respectively; P = 0.02). This difference was reflected in the lower median concentration of total AR in women diagnosed with GDM (163 nmol/L vs. 209 nmol/L, respectively; P < 0.01). The quartile with the highest concentrations of AR had a RR of 0.50 (95% CI: 0.27-0.90) of being diagnosed with GDM, in comparison to the lowest quartile. There was a significant dose response in the GDM risk with higher AR levels.

CONCLUSIONS

We found that a higher consumption of whole grains, reflected both by reported consumption according to the FFQ and AR biomarkers, was associated with a decreased risk of receiving a GDM diagnosis.

Vitamin D status and association with gestational diabetes mellitus in a pregnant cohort in Iceland

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.

Insufficient iodine status in pregnant women as a consequence of dietary changes

Background

Historically, Iceland has been an iodine-sufficient nation due to notably high fish and milk consumption. Recent data suggest that the intake of these important dietary sources of iodine has decreased considerably.

Objective

To evaluate the iodine status of pregnant women in Iceland and to determine dietary factors associated with risk for deficiency.

Methods

Subjects were women (n = 983; 73% of the eligible sample) attending their first ultrasound appointment in gestational weeks 11–14 in the period October 2017–March 2018. Spot urine samples were collected for assessment of urinary iodine concentration (UIC) and creatinine. The ratio of iodine to creatinine (I/Cr) was calculated. Median UIC was compared with the optimal range of 150–249 μg/L defined by the World Health Organization (WHO). Diet was assessed using a semiquantitative food frequency questionnaire (FFQ), which provided information on main dietary sources of iodine in the population studied (dairy and fish).

Results

The median UIC (95% confidence interval (CI)) and I/Cr of the study population was 89 μg/L (42, 141) and 100 (94, 108) μg/g, respectively. UIC increased with higher frequency of dairy intake, ranging from median UIC of 55 (35, 79) μg/L for women consuming dairy products <1 time per week to 124 (98, 151) μg/L in the group consuming dairy >2 times per day (P for trend <0.001). A small group of women reporting complete avoidance of fish (n = 18) had UIC of 50 (21, 123) μg/L and significantly lower I/Cr compared with those who did not report avoidance of fish (58 (34, 134) μg/g vs. 100 (94, 108) μg/g, P = 0.041). Women taking supplements containing iodine (n = 34, 3.5%) had significantly higher UIC compared with those who did not take supplements (141 (77, 263) μg/L vs. 87 (82, 94), P = 0.037).

Conclusion

For the first time, insufficient iodine status is being observed in an Icelandic population. There is an urgent need for a public health action aiming at improving iodine status of women of childbearing age in Iceland.

Association between maternal gluten intake and type 1 diabetes in offspring: national prospective cohort study in Denmark

OBJECTIVE

To examine the association between prenatal gluten exposure and offspring risk of type 1 diabetes in humans.

DESIGN

National prospective cohort study.

SETTING

National health information registries in Denmark.

PARTICIPANTS

Pregnant Danish women enrolled into the Danish National Birth Cohort, between January 1996 and October 2002, MAIN OUTCOME MEASURES: Maternal gluten intake, based on maternal consumption of gluten containing foods, was reported in a 360 item food frequency questionnaire at week 25 of pregnancy. Information on type 1 diabetes occurrence in the participants' children, from 1 January 1996 to 31 May 2016, were obtained through registry linkage to the Danish Registry of Childhood and Adolescent Diabetes.

RESULTS

The study comprised 101 042 pregnancies in 91 745 women, of whom 70 188 filled out the food frequency questionnaire. After correcting for multiple pregnancies, pregnancies ending in abortions, stillbirths, lack of information regarding the pregnancy, and pregnancies with implausibly high or low energy intake, 67 565 pregnancies (63 529 women) were included. The average gluten intake was 13.0 g/day, ranging from less than 7 g/day to more than 20 g/day. The incidence of type 1 diabetes among children in the cohort was 0.37% (n=247) with a mean follow-up period of 15.6 years (standard deviation 1.4). Risk of type 1 diabetes in offspring increased proportionally with maternal gluten intake during pregnancy (adjusted hazard ratio 1.31 (95% confidence interval 1.001 to 1.72) per 10 g/day increase of gluten). Women with the highest gluten intake versus those with the lowest gluten intake (≥20 v <7 g/day) had double the risk of type 1 diabetes development in their offspring (adjusted hazard ratio 2.00 (95% confidence interval 1.02 to 4.00)).

CONCLUSIONS

High gluten intake by mothers during pregnancy could increase the risk of their children developing type 1 diabetes. However, confirmation of these findings are warranted, preferably in an intervention setting.

Development of a dietary screening questionnaire to predict excessive weight gain in pregnancy

Excessive gestational weight gain (GWG) is a risk factor for several adverse pregnancy outcomes, including macrosomia. Diet is one of the few modifiable risk factors identified. However, most dietary assessment methods are impractical for use in maternal care. This study evaluated whether a short dietary screening questionnaire could be used as a predictor of excessive GWG in a cohort of Icelandic women. The dietary data were collected in gestational weeks 11–14, using a 40‐item food frequency screening questionnaire. The dietary data were transformed into 13 predefined dietary risk factors for an inadequate diet. Stepwise backward elimination was used to identify a reduced set of factors that best predicted excessive GWG. This set of variables was then used to calculate a combined dietary risk score (range 0–5). Information regarding outcomes, GWG (n = 1,326) and birth weight (n = 1,651), was extracted from maternal hospital records. In total, 36% had excessive GWG (Icelandic criteria), and 5% of infants were macrosomic (≥4,500 g). A high dietary risk score (characterized by a nonvaried diet, nonadequate frequency of consumption of fruits/vegetables, dairy, and whole grain intake, and excessive intake of sugar/artificially sweetened beverages and dairy) was associated with a higher risk of excessive GWG. Women with a high (≥4) versus low (≤2) risk score had higher risk of excessive GWG (relative risk = 1.23, 95% confidence interval, CI [1.002, 1.50]) and higher odds of delivering a macrosomic offspring (odds ratio = 2.20, 95% CI [1.14, 4.25]). The results indicate that asking simple questions about women's dietary intake early in pregnancy could identify women who should be prioritized for further dietary counselling and support.

Maternal Macronutrient Intake and Offspring Blood Pressure 20 Years Later

Background

Results from 2 cohort studies in Scotland established in the 1940s and 1950s (Aberdeen and Motherwell) suggested that a high protein diet during pregnancy might adversely influence offspring blood pressure at adult age. Our objective was to examine this association in the Danish Fetal Origins Cohort (DaFO88).

Methods and Results

This was a prospective birth cohort of 965 women who gave birth in 1988–1989 in Aarhus, Denmark, and whose offspring (n=434) participated in a clinical examination ≈20 years later. Macronutrient intake was assessed in gestational week 30. Multivariable adjusted linear regression was used to examine the relation between higher maternal protein intake, at the expense of carbohydrates, and offspring blood pressure (isocaloric substitution). Main analyses were adjusted for mother's age during pregnancy, prepregnancy body mass index, parity, smoking during pregnancy, educational level, and offspring's sex. The mean total energy intake was 8.7 MJ/day (SD 2.3 MJ/day). The mean energy from carbohydrate, fat, and protein intake was 51, 31, and 16 of total energy, respectively. The results showed that after adjustment, higher maternal protein intake was associated with slightly higher offspring diastolic blood pressure (highest compared with the lowest quintile of protein intake: ∆=2.4 mm Hg; 95% CI 0.4–4.4; P=0.03 for trend). Similar differences, although not significant, were found for systolic blood pressure (∆=2.6 mm Hg; 95% CI −0.0 to 5.3; P=0.08 for trend).

Conclusions

Higher maternal dietary protein intake at the expense of carbohydrates was associated with a modest increase in offspring blood pressure in young adulthood.

Maternal diet, gestational weight gain, and inflammatory markers during pregnancy

OBJECTIVE

To examine the associations of gestational weight gain (GWG) and diet with low-grade inflammation in pregnancy.

METHODS

A cross-sectional analysis of 671 pregnant women was performed, and diet was assessed in gestational week 30. GWG was recorded in weeks 30 and ∼37 (difference between the weight recorded at these time points and pre-pregnancy weight). Markers of inflammation, high-sensitivity C-reactive protein (hsCRP), serum amyloid A (SAA), interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor-α were quantified in serum from week 30.

RESULTS

After adjusting for age, pre-pregnancy BMI, parity, smoking status, and education, each 1 kg increase in GWG was associated with 3% (95% CI: 1-5) higher hsCRP and 3% (95% CI: 1-4) higher SAA concentrations, which corresponded to ∼18% to 25% increase in these biomarkers among those with excessive weight gain. GWG was inversely associated with IL-8 while no associations were found for the other inflammatory markers. With respect to diet, women in the highest compared with lowest quintile of protein intake had 26% (95% CI: 3-54) higher hsCRP concentrations. This increase appeared to be driven by intake of animal protein. A similar pattern was observed for SAA.

CONCLUSIONS

Excessive GWG, as well as high intake of animal protein, was associated with higher concentrations of inflammatory factors.