Ethnic differences in body mass index trajectories from 18 years to postpartum in a population-based cohort of pregnant women in Norway

Cohort profile update: the Norwegian STORK Groruddalen (STORK G) pregnancy and birth cohort-the role of ethnicity and causal pathways for obesity, type 2 diabetes, cardiovascular disease and other health issues

PURPOSE

The STORK Groruddalen cohort was set up in 2008 to explore ethnic differences in: (1) maternal health, primarily gestational diabetes (GDM) and related health issues during pregnancy and post partum, and effects of exposures on risk for type 2 diabetes, cardiovascular disease and other health issues, and (2) offspring's growth and body composition, overweight/obesity and effects of early life exposures.

PARTICIPANTS

823 women (74% of invited) were followed from gestational week (GW) 15. Data were collected from 618 fathers. In total, 59% of women and 53% of fathers had origin from non-Western countries. Maternal mean age was 29.9 years (SD 4.9), and body mass index (BMI) 25.3 kg/m2 (4.9). Data were obtained from 772 women (94%) at GW 28, and 662 women (80%) 14 weeks post partum. Eleven years post partum, 385 women (53% of eligible/47% of original cohort) attended, age was 42.0 years (4.8) and BMI 27.1 kg/m2 (5.1). We have data for 783 children at birth, and for 586 at last time point, mean age 8.6 (0.5) years, weight 30.7 (6.8) kg and length 133.9 (6.3) cm.

FINDINGS TO DATE

We collected questionnaire data from parents, clinical measurements and blood samples from mothers, and data on children's growth (mid-pregnancy to 8 years). Our biobank includes maternal blood and urine samples, biopsy material from placentas and umbilical venous cord blood. We found several clinically important differences in maternal health, with higher risk in ethnic minority groups for GDM, insulin resistance, vitamin D and iron deficiency, depressive symptoms and physical inactivity. Contrasting patterns of fetal growth and risk of overweight/thinness at preschool age were observed across ethnic groups. Maternal GDM, obesity and high gestational weight gain were associated with children's BMI trajectories.

FUTURE PLANS

We will examine the impact of maternal and fetal health and development during pregnancy on long-term outcomes for mothers and offspring.

TRIAL REGISTRATION NUMBER

Project title STORK G-2: Women and Risk of Type 2 Diabetes NCT03870724 (ClinicalTrials.gov).

The influence of metabolic factors and ethnicity on breast cancer risk, treatment and survival: The Oslo ethnic breast cancer study

BACKGROUND

Breast cancer risk remains higher in high-income compared with low-income countries. However, it is unclear to what degree metabolic factors influence breast cancer development in women 30 years after immigration from low- to a high-incidence country.

METHODS

Using Cox regression models, we studied the association between pre-diagnostic metabolic factors and breast cancer development, and whether this association varied by ethnicity among 13,802 women participating in the population-based Oslo Ethnic Breast Cancer Study. Ethnic background was assessed and pre-diagnostic metabolic factors (body mass index, waist:hip ratio, serum lipids and blood pressure) were measured. A total of 557 women developed invasive breast cancer, and these women were followed for an additional 7.7 years.

RESULTS

Among women with an unfavorable metabolic profile, women from south Asia, compared with western European women, had a 2.3 times higher breast cancer risk (HR 2.30, 95% CI 1.18-4.49). Compared with the western European women, the ethnic minority women were more likely to present with triple-negative breast cancer (TNBC) (OR 2.11, 95% CI 0.97-4.61), and less likely to complete all courses of planned taxane treatment (OR 0.26, 95% CI 0.08-0.82). Among TNBC women, above-median triglycerides:HDL-cholesterol (>0.73) levels, compared with below-median triglycerides:HDL-cholesterol (≤0.73) levels, was associated with 2.9 times higher overall mortality (HR 2.88, 95% CI 1.02-8.11).

CONCLUSIONS

Our results support the importance of metabolic factors when balancing breast cancer prevention and disease management among all women, and in particular among non-western women migrating from a breast cancer low-incidence to a high-incidence country.

Preconception leisure-time physical activity and family history of stroke and myocardial infarction associate with preterm delivery: findings from a Norwegian cohort

Background

Preterm birth poses short and long-term health consequences for mothers and offspring including cardiovascular disease sequelae. However, studies evaluating preexisting family history of cardiovascular disease and risk factors, such as physical activity, as they relate prospectively to risk of delivering preterm are lacking.

Objectives

To evaluate whether preconception past-year weekly leisure-time physical activity or a family history of stroke or of myocardical infarction prior to age 60 years in first degree relatives associated, prospectively, with preterm delivery.

Design

Cohort study. Baseline data from Cohort Norway (1994–2003) health surveys were linked to the Medical Birth Registry of Norway for identification of all subsequent births (1994–2012). Logistic regression models provided odds ratios (OR) and 95% confidence intervals (CI) for preterm delivery (< 37 weeks gestation); multinomial logistic regression provided OR for early preterm (< 34 weeks) and late preterm (34 through to end of 36 weeks gestation) relative to term deliveries.

Results

Mean (SD) length of time from baseline health survey participation to delivery was 5.6 (3.5) years. A family history of stroke associated with a 62% greater risk for late preterm deliveries (OR 1.62; CI 1.07–2.47), while a family history of myocardial infarction associated with a 66% greater risk of early preterm deliveries (OR 1.66; CI 1.11–2.49). Sensitivity analyses, removing pregnancies complicated by hypertensive disorders of pregnancy, diabetes mellitus, and stillbirth deliveries, gave similar results. Preconception vigorous physical activity of three or more hours relative to less than 1 h per week associated with increased risk of early preterm delivery (OR 1.52; 95% CI 1.01–2.30), but not late or total preterm deliveries. Light physical activity of three or more hours per week relative to less activity prior to pregnancy was not associated with early, late, or total preterm deliveries.

Conclusions

Results suggest that family history of cardiovascular disease may help identify women at risk for preterm delivery. Further, research is needed regarding preconception and very early pregnancy vigorous physical activity and associated risks.

Lipid and lipoprotein concentrations during pregnancy and associations with ethnicity

Background

To describe ethnic differences in concentrations of lipids and lipoproteins, and their changes, during pregnancy to postpartum.

Methods

This was a population-based cohort study conducted in primary antenatal care in Norway. The participants (n = 806) were healthy, pregnant women, 59% were ethnic minorities. Outcomes were triglycerides, total cholesterol, HDL- and LDL-cholesterol, analysed from fasting blood samples drawn at gestational age (weeks) 15, 28 and 14 weeks postpartum. We performed linear regression models and linear mixed models to explore the total effect of ethnicity on the outcomes, adjusting for gestational age /week postpartum, maternal age and education. The analyses are corrected for multiple testing using the Bonferroni correction.

Results

At gestational age 15, triglyceride concentrations were lower in women of African origin (1.03 mmol/mol (95% CI: 0.90, 1.16)) and higher in women of South Asian (primarily Pakistan and Sri Lanka) origin (1.42 mmol/mol (1.35, 1.49)) and East Asian (primarily Vietnam, Philippines and Thailand) origin (1.58 mmol/mol (1.43, 1.73)) compared with Western Europeans (1.26 mmol/mol (1.20, 1.32)). Women of Asian and African origin had a smaller increase in triglycerides, LDL- and total cholesterol from gestational age 15 to 28. At gestational age 28, LDL-cholesterol levels were lowest among East Asians (3.03 mmol/mol (2.72, 3.34)) compared with Western Europeans (3.62 mmol/mol (3.50, 3.74)). Triglycerides and HDL-cholesterol were lower postpartum than at gestational age 15 in all groups, but the concentration of LDL-cholesterol was higher, except in Africans. South and East Asian women had lower HDL-cholesterol and higher triglycerides postpartum, while African women had lower triglycerides than Western Europeans.

Conclusion

We found significant differences in the concentrations of lipids and lipoproteins and their changes during pregnancy and the early postpartum period related to ethnic origin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04524-2.

The safety and efficacy of supervised exercise on pregnant women with overweight/obesity: A systematic review and meta-analysis of randomized controlled trials

Behavioural modification through physical activity and dietary counselling has been shown to have beneficial effects on pregnant women with overweight/obesity. Whether exercise alone with supervision (ie, supervised exercise) may also benefit for pregnant women with overweight/obesity is still unknown. This systematic review and meta-analysis aimed to determine the safety and efficacy of supervised exercise on pregnant women with overweight/obesity. PubMed, Cochrane library, Embase (Ovid), CINAHL (EBSCO), and Web of Science were used to search publications using a combination of main keywords "obesity", "exercise", "pregnant women", and "randomised controlled trial". From a total of 740 publications, 11 randomized controlled trials were included. All studies reported no adverse effects of supervised exercise on pregnant women with overweight/obesity. Of interest, this meta-analysis showed gestational weight gain (GWG) was lower in the supervised exercise group as compared to control (Mean difference 0.88 kg, 95%CI -1.73 to -0.03, P = .04). There was a significant effect of supervised exercise on post-prandial blood glucose (MD: -0.24, 95%CI -0.47 to -0.01, P = .04) and insulin resistance (HOMA-IR) (MD: -0.18, 95%CI -0.30 to -0.05, P = .005). There were no differences in risk of gestational diabetes mellitus, pre-eclampsia/gestational hypertension, and newborn outcomes (eg, infants birth weight, preterm birth incident, and gestational age) (all P > .05). This meta-analysis might suggest beneficial effects of supervised exercise on pregnant women with overweight/obesity to prevent excessive GWG, attenuates insulin resistance, and the post-prandial blood glucose level.