Epigenome-wide association study of DNA methylation in maternal blood leukocytes with BMI in pregnancy and gestational weight gain

OBJECTIVES

We aimed to discover CpG sites with differential DNA methylation in peripheral blood leukocytes associated with body mass index (BMI) in pregnancy and gestational weight gain (GWG) in women of European and South Asian ancestry. Furthermore, we aimed to investigate how the identified sites were associated with methylation quantitative trait loci, gene ontology, and cardiometabolic parameters.

METHODS

In the Epigenetics in pregnancy (EPIPREG) sample we quantified maternal DNA methylation in peripheral blood leukocytes in gestational week 28 with Illumina's MethylationEPIC BeadChip. In women with European (n = 303) and South Asian (n = 164) ancestry, we performed an epigenome-wide association study of BMI in gestational week 28 and GWG between gestational weeks 15 and 28 using a meta-analysis approach. Replication was performed in the Norwegian Mother, Father, and Child Cohort Study, the Study of Assisted Reproductive Technologies (MoBa-START) (n = 877, mainly European/Norwegian).

RESULTS

We identified one CpG site significantly associated with GWG (p 5.8 × 10-8) and five CpG sites associated with BMI at gestational week 28 (p from 4.0 × 10-8 to 2.1 × 10-10). Of these, we were able to replicate three in MoBa-START; cg02786370, cg19758958 and cg10472537. Two sites are located in genes previously associated with blood pressure and BMI. DNA methylation at the three replicated CpG sites were associated with levels of blood pressure, lipids and glucose in EPIPREG (p from 1.2 × 10-8 to 0.04).

CONCLUSIONS

We identified five CpG sites associated with BMI at gestational week 28, and one with GWG. Three of the sites were replicated in an independent cohort. Several genetic variants were associated with DNA methylation at cg02786379 and cg16733643 suggesting a genetic component influencing differential methylation. The identified CpG sites were associated with cardiometabolic traits.

CLINICALTRIALS

GOV REGISTRATION NO

Not applicable.

Objectively recorded physical activity and the association with gestational diabetes

The aim of this population-based study was to assess the association between objectively recorded physical activity (PA) in early gestation and gestational diabetes mellitus (GDM) identified at 28 weeks of gestation in a multi-ethnic cohort of healthy pregnant women in Oslo, Norway. In total, 759 women were included. In early gestation (<20 weeks), light-, moderate-, and vigorous-intensity PA and number of steps were objectively recorded (SenseWear™ Armband Pro3), and self-reported PA, demographics, and anthropometrics were collected. The 75-g oral glucose tolerance test was performed at 28 weeks of gestation. Women with GDM had fewer objectively recorded steps (mean 7964 steps/day vs 8879 steps/day, P < 0.001) and minutes of moderate-to-vigorous-intensity PA (median 62 min/day vs 75 min/day, P = 0.004) in early gestation than women without GDM. Additionally, 30% of women with GDM compared with 44% (P < 0.001) of women without GDM self-reported regular PA before pregnancy. The significant inverse association between objectively recorded steps per day in early gestation and GDM persisted after adjustment for ethnic origin, weeks of gestation, age, parity, pre-pregnancy BMI, early life socioeconomic position, and self-reported regular PA before pregnancy. The adjusted odds ratio for GDM decreased 19% per standard deviation (3159 steps) increase in objectively recorded steps per day (P = 0.039). Daily life PA in early gestation measured as steps/day was associated with lower risk of GDM.

The prevalence of urinary incontinence in pregnancy among a multi-ethnic population resident in Norway

OBJECTIVES

To investigate prevalence of urinary incontinence (UI) in a multi-ethnic population of pregnant women, and to analyse for possible associations of the known risk factors for UI in such a population.

DESIGN

Population-based cross-sectional study.

SETTING

All pregnant women in three administrative city districts attending the Child Health Clinics.

POPULATION AND SAMPLE

Out of 823 women identified in the [corrected] first trimester, 772 (94%) [corrected] agreed to participate in the study at 28 weeks of gestation. Inclusion criteria were: healthy women at 20 weeks of gestation or less and able to communicate in Norwegian, Arabic, English, Sorani, Somali, Tamil, Turkish, Urdu or Vietnamese.

METHODS

Differences between ethnic groups were tested by simple descriptive statistics. Associations were estimated by logistic regression analysis and presented as crude (cOR) and adjusted (aOR) odds ratios.

MAIN OUTCOME MEASURES

Prevalence of UI as ascertained using the International Consultation on Incontinence Questionnaire-urinary incontinence-short form.

RESULTS

Prevalence rates of UI at 28 weeks of gestation were 26% for women of African origin, 36% for women of Middle Eastern origin, 40% for women of East Asian origin, 43% for women of South Asian origin and 45% for women of European/North American origin. The difference was significant between women of African and European/North American origins (P = 0.011) and between women of African and South Asian origins (P = 0.035). Age (aOR 1.05; 95% CI 1.01-1.09) and parity (aOR 2.34; 95% CI 1.66-3.28) were positively associated with the prevalence of UI in pregnancy. Women of African origin had significantly reduced odds for UI (aOR 0.42; 95% CI 0.20-0.87). East Asian and African women reported the highest perceived impact of UI in pregnancy.

CONCLUSIONS

A high prevalence of UI was found in a multi-ethnic pregnant population.

[Pyelonephritis in children--a retrospective study]

BACKGROUND

Urinary tract infection (UTI) is a common bacterial infection in childhood, sometimes associated with urological malformations and, in a few cases, causing permanent renal damage.

MATERIAL AND METHODS

A retrospective study was performed of children with UTI first time admitted to Ullevål Hospital during the period 1988-97. All medical records with diagnoses related to the urinary tract were investigated. Criteria for inclusion were bacteriuria and temperature > or = 38.5 degrees C in children over one year of age, and bacteriuria below one year of age.

RESULTS

Age, sex, symptoms, urine sampling method, medical treatment and radiological investigations were evaluated. 180 children were included, (38% boys, 62% girls), 87% of the boys were referred during this first year of life. Fever as sole symptom was found in one of six. Urinary tract related symptoms were rare. Urine sampling was performed by suprapubic aspiration in only 7%, and was not specified in half of the samples. Imaging evaluation was performed in almost all children. More than half of the evaluated children had one or more abnormalities, vesicoureteric reflux being the most frequent.

INTERPRETATION

In our material we find a high frequency of urological malformations. Better routines for urine sampling and evaluation of long term complications are suggested.