Associations between maternal physical activity in early and late pregnancy and offspring birth size: remote federated individual level meta-analysis from eight cohort studies.

OBJECTIVE: Evidence on the impact of leisure time physical activity (LTPA) in pregnancy on birth size is inconsistent. We aimed to examine the association between LTPA during early and late pregnancy and newborn anthropometric outcomes. DESIGN: Individual level meta-analysis, which reduces heterogeneity across studies. SETTING: A consortium of eight population-based studies (seven European and one US) comprising 72 694 participants. METHODS: Generalised linear models with consistent inclusion of confounders (gestational age, sex, parity, maternal age, education, ethnicity, BMI, smoking, and alcohol intake) were used to test associations between self-reported LTPA at either early (8-18 weeks gestation) or late pregnancy (30+ weeks) and the outcomes. Results were pooled using random effects meta-analyses. MAIN OUTCOME MEASURES: Birth weight, large-for-gestational age (LGA), macrosomia, small-for-gestational age (SGA), % body fat, and ponderal index at birth. RESULTS: Late, but not early, gestation maternal moderate to vigorous physical activity (MVPA), vigorous activity, and LTPA energy expenditure were modestly inversely associated with BW, LGA, macrosomia, and ponderal index, without heterogeneity (all: I2  = 0%). For each extra hour/week of MVPA, RR for LGA and macrosomia were 0.97 (95% CI: 0.96, 0.98) and 0.96 (95% CI: 0.94, 0.98), respectively. Associations were only modestly reduced after additional adjustments for maternal BMI and gestational diabetes. No measure of LTPA was associated with risk for SGA. CONCLUSIONS: Physical activity in late, but not early, pregnancy is consistently associated with modestly lower risk of LGA and macrosomia, but not SGA. TWEETABLE ABSTRACT: In an individual participant meta-analysis, late pregnancy moderate to vigorous physical activity modestly reduced birth size outcomes.

Being born small-for-gestational-age is associated with an unfavourable dietary intake in Danish adolescent girls: findings from the Danish National Birth Cohort.

Individuals born small have an increased risk for developing type 2 diabetes. Altered food preferences in these subjects seem to play a role; however, limited evidence is available on the association between being born small-for-gestational-age (SGA) at term and food intake in adolescence. Alterations in leptin, ghrelin and dopamine levels are suggested mechanisms linking SGA with later food intake. From a large prospective Danish National Birth Cohort, we compared dietary intake of adolescents being born SGA with normal-for-gestational-age (NGA) adolescents. Intake of foods and nutrients was assessed by a validated food frequency questionnaire in a subsample of 15,607 14-year-old individuals born at term. SGA was defined by birth weight (BW) <10th percentile (n = 1470) and NGA as BW between 10 and 90th percentile (n = 14,137) according to sex and gestational age-specific BW standard curves. Girls born SGA had a 7% (95% CI: 3-12%, P = 0.002) higher intake of added sugar and a 2-8% lower intake of dietary fibre, vegetables, polyunsaturated fatty acids, and total n-6, compared with NGA girls (P < 0.05). Adjusting for parental socio-occupational status, maternal smoking and diet in pregnancy did not substantially change the differences in dietary intake, except from dietary fibre, which were no longer statistically significant. No significant differences in dietary intake between SGA and NGA boys were found. In summary, girls born SGA had an unfavourable dietary intake compared with NGA girls. These differences persisted after controlling for potential confounders, thus supporting a fetal programming effect on dietary intake in girls born SGA at term. However, residual confounding by other factors operating early in childhood cannot be excluded.

Plasma Concentrations of Long Chain N-3 Fatty Acids in Early and Mid-Pregnancy and Risk of Early Preterm Birth.

BACKGROUND: Fish oil supplementation has been shown to delay spontaneous delivery, but the levels and clinical significance remain uncertain. We examined the association between plasma fatty acids quantified in pregnancy and subsequent risk of early preterm birth. METHODS: In a case-control design nested in the Danish National Birth Cohort, we identified 376 early preterm cases (<34 gestational weeks, excluding preeclampsia cases) and 348 random controls. Plasma eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA% of total fatty acids), were measured twice in pregnancy, at gestation weeks 9 and 25 (medians). Odds ratios and 95% confidence intervals (CI's) for associations between EPA+DHA and early preterm risk were estimated by logistic regression, adjusted for the woman's age, height, pre-pregnancy BMI, parity, smoking, and socioeconomic factors. Hypotheses and analytical plan were defined and archived a priori. FINDINGS: Analysis using restricted cubic splines of the mean of 1st and 2nd sample measurements showed a strong and significant non-linear association (p < 0.0001) in which the risk of early preterm birth steeply increased when EPA+DHA concentrations were lower than 2% and flattened out at higher levels. Women in the lowest quintile (EPA+DHA < 1.6%) had 10.27 times (95% confidence interval 6.80-15.79, p < 0.0001) increased risk, and women in the second lowest quintile had 2.86 (95% CI 1.79-4.59, p < 0.0001) times increased risk, when compared to women in the three aggregated highest quintiles (EPA+DHA ≥ 1.8%). INTERPRETATION: Low plasma concentration of EPA and DHA during pregnancy is a strong risk factor for subsequent early preterm birth in Danish women.

Birth by cesarean section in relation to adult offspring overweight and biomarkers of cardiometabolic risk.

BACKGROUND: Birth by Cesarean section (C-section) may increase the risk for non-communicable diseases. We aimed to examine the relation of birth by C-section with offspring overweight and markers of cardiometabolic risk in a prospective observational cohort with 20 years of follow-up. METHODS: The Danish Fetal Origins Cohort enrolled 965 pregnant women in 1988-1989. In 2008, a follow-up study of the offspring was completed. The offspring were invited to participate in a clinical examination with measurements of anthropometry and a fasting blood sample (n=443). In addition, 252 offspring completed a self-administered questionnaire with questions on height and weight, leaving us with a study sample of 695 offspring. Offspring overweight at 20 years was defined as body mass index (BMI)⩾25 kg m-2. We also analyzed blood pressure and fasting blood samples for cardiometabolic risk factors including insulin, leptin and adiponectin, and lipid concentrations. RESULTS: In the cohort, 7% were born by C-section, and at age 20 years, 18% of the offspring had a BMI ⩾25 kg m-2. Birth by C-section was associated with increased odds of overweight or obesity at 20 years (Odds ratio=2.17 (95% confidence interval (CI): 1.10, 4.27)) after adjustment for potential confounders. Birth by C-section was also associated with higher serum concentrations of total cholesterol (8.5%, 95% CI: 1.1-16.5), low-density lipoprotein cholesterol (12.6%, 95% CI: 1.0, 25.5), leptin (73.1%, 95% CI: 5.9, 183.1) and Apolipoprotein B (0.08 g l-1, 95% CI: 0.04, 0.15). In contrast, birth by C-section was not related to blood pressure or serum concentrations of insulin, adiponectin, triglycerides, high-density lipoprotein or Apolipoprotein A. CONCLUSION: Birth by C-section was associated with higher frequency of dysmetabolic traits in offspring independently of shared risk factors. Further research aimed at replicating these findings and elucidating the underlying biological mechanisms of this relation is needed.

Prenatal exposure to persistent organic pollutants and offspring allergic sensitization and lung function at 20 years of age.

BACKGROUND: Prenatal exposures to persistent organic pollutants (POPs) have been associated with asthma medication use and self-reported symptoms, but associations with lung function and allergic sensitization have been minimally explored. The aim of the study was to examine the associations between prenatal exposures to POPs and allergic sensitization and lung function in 20-year-old offspring. METHODS: In a Danish cohort of 965 pregnant women established in 1988-1989, six polychlorinated biphenyl (PCB) congeners, hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (p,p'-DDE) were quantified in archived maternal serum drawn in gestational week 30 (n = 872). Among those with available maternal exposure information, at age 20, 421 offspring attended attended a clinical examination including measurements of allergic sensitization (serum-specific IgE ≥ 0.35 kUA /L) (n = 418) and lung function [forced expiratory volume in one second (FEV1 ) and forced vital capacity (FVC)] (n = 414). RESULTS: There were no associations between maternal concentrations of POPs and offspring allergic sensitization at 20 years of age. Maternal concentrations of POPs were, however, positively associated with offspring airway obstruction (FEV1 /FVC < 75%). Compared to offspring in the first tertile of exposure, offspring in the third tertile of dioxin-like PCB exposure had an OR of 2.96 (95% CI: 1.14-7.70). Similar associations for non-dioxin-like PCBs, HCB, and p,p'-DDE were 2.68 (1.06-6.81), 2.63 (1.07, 6.46), and 2.87 (1.09, 7.57), respectively. No associations were observed with reduced lung function (FEV1 % of predicted value < 90%). CONCLUSION AND CLINICAL RELEVANCE: Our data indicate that prenatal exposure to POPs appears to be associated with airway obstruction but not allergic sensitization at 20 years of age. The findings support that chronic obstructive lung diseases may have at least part of their origins in early life.

Familial risks in nervous system tumours: joint Nordic study.

BACKGROUND: Familial nervous system cancers are rare and limited data on familial aspects are available particularly on site-specific tumours. METHODS: Data from five Nordic countries were used to analyse familial risks of nervous system tumours. Standardised incidence ratios (SIRs) were calculated for offspring of affected relatives compared with offspring of non-affected relatives. RESULTS: The total number of patients with nervous system tumour was 63 307, of whom 32 347 belonged to the offspring generation. Of 851 familial patients (2.6%) in the offspring generation, 42 (4.7%) belonged to the families of a parent and at least two siblings affected. The SIR of brain tumours was 1.7 in offspring of affected parents; it was 2.0 in siblings and 9.4 in families with a parent and sibling affected. For spinal tumours, the SIRs were much higher for offspring of early onset tumours, 14.0 for offspring of affected parents and 22.7 for siblings. The SIRs for peripheral nerve tumours were 16.3 in offspring of affected parents, 27.7 in siblings and 943.9 in multiplex families. CONCLUSION: The results of this population-based study on medically diagnosed tumours show site-, proband- and age-specific risks for familial tumours, with implications for clinical genetic counselling and identification of the underlying genes.

Population attributable fractions for ovarian cancer in Swedish women by morphological type.

Using the Swedish Family-Cancer Database, among a total of 1,030,806 women followed from 1993 through 2004, invasive and borderline epithelial ovarian cancer was identified in 3306 and 822 women respectively, with data on family history, reproductive variables, residential region and socioeconomic status. Relative risks and population-attributable fractions (PAFs) were estimated by Poisson regression. The overall PAFs of invasive epithelial ovarian cancer for family history and for reproductive factors were 2.6 and 22.3%, respectively, for serous/seropapillary cystadenocarcinoma (3.0 and 19.1%), endometrioid carcinoma (2.6 and 26.6%), mucinous cystadenocarcinoma (0.5 and 23.9%) and clear-cell carcinoma (2.6 and 73.9%). The corresponding PAFs of borderline tumours due to family history were lower, but higher due to reproductive factors. Family history, low parity and young age at first birth were associated with elevated risks. The risks for women with a family history were among the highest, but these women accounted for the smallest proportion of the cases, giving the lowest PAFs.

Occupation and bladder cancer: a cohort study in Sweden.

In a follow-up study of occupational exposures and bladder cancer, an increased risk was observed after an adjustment for smoking, for physicians, administrators and managers, clerical workers and sales agents among men and assistant nurses among women. For physicians, the reason may be early diagnosis; for the other groups a sedentary type of work may have a role in bladder cancer aetiology.

Familial clustering of ovarian and endometrial cancers.

Data on the association of ovarian cancer with other cancers in families are limited, and no data are available on the involvement of specific morphological types. The nationwide Swedish Family-Cancer Database on 10.2 million individuals and 19175 invasive ovarian cancers was used to calculate standardised incidence ratios (SIRs) and 95% confidence intervals (CIs) for familial ovarian cancer in 0-66-year-old daughters when mothers or sisters were affected. The SIR for concordant ovarian cancers was increased. When the mother or sister had breast cancer, the SIRs were 1.21 and 1.48, respectively; when they had endometrial cancer, the SIRs were 1.45 and 2.53. Multiple myeloma in the mother was associated with a risk of ovarian cancer in the daughter. The risk of endometrioid ovarian cancer was 3.40 in the daughter when the mother presented with endometrial cancer. Our data show a strong familial coupling of ovarian and endometrial cancers, which appears to be specific to the endometrioid morphology.

The nation-wide Swedish family-cancer database--updated structure and familial rates.

The Swedish Family-Cancer Database was expanded to include all Swedes born in 1932 and later (offspring) with their parents, totaling 10.2 million individuals. Cancer cases were retrieved from the Swedish Cancer Registry from the years 1958 to 1998, including over 1 million primary cancers and in situ tumors. Some 10%, of offspring diagnosed with cancer lack any parental information. Incidence rates of cancers were similar in the database and in the Cancer Registry to age 70, but at higher ages the rates in the Database were lower, probably because of selection. The familial risk for all types of cancer in offspring was 1.73 when a parent had the same type of cancer. The familial rates were increased for all main cancer sites, except for the upper aerodigestive tract, stomach, liver, pancreas and bone marrow (leukemia). The rates were 7.47 for thyroid, 4.69 for testis, and over 2.00 for melanoma, ovary, prostate, skin, endocrine glands and endometrium.