Parental age and birth defects: a sibling study

Higher parental age at childbearing has generated much attention as a potential risk factor for birth disorders; however, previous research findings are mixed. Existing studies have exploited variation in parental age across families, which is problematic because families differ not only in parental age but also in genetic and environmental factors. To isolate the effects of parental age, holding many genetic and environmental factors constant, we exploit the variation in parental age within families and compare outcomes for full siblings. The study data were retrieved from the Medical Birth Registry of Norway, which covers the entire population of births in Norway over an extended period (totaling 1.2 million births). Using variation in parental age when siblings were born, we find large and convex effects of increased parental age on the increased risk of birth disorders. To facilitate comparison with the existing literature, we also estimate the effects of parental age using variation in parental age across families and find that the effects are substantially weaker. We conclude that the existing literature may have underestimated the negative effects of parental aging on adverse offspring outcomes.

Low birthweight is associated with lower glomerular filtration rate in middle-aged mainly healthy women

Background Low birthweight (LBW) has been shown to increase the risk of severe kidney disease. Studies have also shown associations between LBW and lower estimated glomerular filtration rate (GFR) in young adults. In this study we investigated whether LBW associates with measured GFR (mGFR) in middle-aged mainly healthy adults. Methods We invited individuals with LBW (1100–2300 g) and individuals with normal BW (NBW; 3500–4000 g) ages 41–52 years. GFR was measured using plasma clearance of iohexol. BW and BW for gestational age (BWGA) were obtained from the Medical Birth Registry of Norway and tested as main predictors. GFR was the main outcome. Results We included 105 individuals (57 LBW and 48 NBW). The mean GFR was 95 ± 14 mL/min/1.73 m2 in the LBW group and 100 ± 13 mL/min/1.73 m2 in the NBW group (P = 0.04). There was a significant sex difference: in women the mean GFR was 90 ± 12 versus 101 ± 14 mL/min/1.73 m2 in the LBW and NBW groups, respectively (P = 0.006), whereas corresponding values for men were 101 ± 15 versus 100 ± 11 mL/min/1.73 m2 (P = 0.7). Using linear regression, we found the GFR was 4.5 mL/min/1.73 m2 higher per 1 kg higher BW for women (P = 0.02), with a non-significant 1.2 mL/min/1.73 m2 lower GFR for men (P = 0.6). In analyses of BWGA, there was also a significant association for women, but not for men. Conclusions Middle-aged mainly healthy women with LBW had lower mGFR as compared with women with NBW. No such difference was found for men.

Evaluation of incomplete maternal smoking data using machine learning algorithms: a study from the Medical Birth Registry of Norway

Background The Medical Birth Registry of Norway (MBRN) provides national coverage of all births. While retrieval of most of the information in the birth records is mandatory, mothers may refrain to provide information on her smoking status. The proportion of women with unknown smoking status varied greatly over time, between hospitals, and by demographic groups. We investigated if incomplete data on smoking in the MBRN may have contributed to a biased smoking prevalence. Methods In a study population of all 904,982 viable and singleton births during 1999–2014, we investigated main predictor variables influencing the unknown smoking status of the mothers’ using linear multivariable regression. Thereafter, we applied machine learning to predict annual smoking prevalence (95% CI) in the same group of unknown smoking status, assuming missing-not-at-random. Results Overall, the proportion of women with unknown smoking status was 14.4%. Compared to the Nordic country region of origin, women from Europe outside the Nordic region had 15% (95% CI 12–17%) increased adjusted risk to have unknown smoking status. Correspondingly, the increased risks for women from Asia was 17% (95% CI 15–19%) and Africa 26% (95% CI 23–29%). The most important machine learning prediction variables regarding maternal smoking were education, ethnic background, marital status and birth weight. We estimated a change from the annual observed smoking prevalence among the women with known smoking status in the range of − 5.5 to 1.1% when combining observed and predicted smoking prevalence. Conclusion The predicted total smoking prevalence was only marginally modified compared to the observed prevalence in the group with known smoking status. This implies that MBRN-data may be trusted for health surveillance and research.

Caesarean section and the association with migraine: a retrospective register-linked HUNT population cohort study

ObjectivesTo evaluate the association between caesarean section and migraine in a population-based register-linked cohort study.SettingData from the population-based Nord-Trøndelag Health Studies (HUNT2 and HUNT3) were linked to information from the Norwegian Medical Birth Registry.Participants65 343 participants responded to the headache questions in any of the two HUNT studies. Only those answering the headache questions in HUNT2 or 3 and had information about mode of delivery in the Norwegian Medical Birth Registry (born after 1967) were included. Our final sample consisted of 6592 women and 4602 men, aged 19–41 years.OutcomesORs for migraine given caesarean section. Analyses were performed in multivariate logistic regression models.ResultsAfter adjusting for sex, age and fetal growth restriction, delivery by caesarean section was not associated with migraine later in life (OR 0.86, 95% CI 0.64 to 1.15). Delivery by caesarean section was associated with a reduced OR of non-migrainous headache (OR 0.77, 95% CI 0.60 to 0.99).ConclusionNo association was found between caesarean section and migraine in this population-based register-linked study.

P0731LOW BIRTH WEIGHT IS ASSOCIATED WITH LOWER MEASURED GLOMERULAR FILTRATION RATE IN ADULT AGE

Background and Aims Low birth weight (LBW) has been shown to increase the risk of severe kidney disease. Studies have also shown that LBW is associated with lower estimated glomerular filtration rate (eGFR) or creatinine clearance in young adults. In the present study we investigated whether LBW associate with measured glomerular filtration rate (mGFR) in 40-50 year old adults. Method Retrospective longitudinal cohort study using the Medical Birth Registry of Norway to invite 200 individuals with LBW (birth weight ≤ 2300 gram) and 200 individuals with normal birth weight (NBW, 3500 – 4000 grams). All participants were aged 41 – 52 at time of examination. GFR was measured using plasma clearance of iohexol. Birth weight and gestational age were reported from the Medical Birth Registry. Main outcome was difference in measured GFR. Results We included 105 individuals – 57 LBW and 48 NBW – 55% females. Mean GFR was 94.8 ± 14.2 ml/min/1.73m2 in the LBW group and 100.2 ± 12.5 ml/min/1.73m2 in the NBW group (p=0.043). In females the mean GFR was 90.4 ± 12.2 ml/min/1.73m2 in the LBW group and 100.5 ± 14.0 ml/min/1.73m2 in the NBW group (p=0.005). In males the mean GFR was 101.4 ± 14.5 and 100 ± 11.2 ml/min/1.73m2 in the LBW and NBW groups respectively (p=0.7). In a multi-regression model adjusting for age, maternal age and maternal civil status, we found an increase in mGFR of 4.5 ml/min/1.73m2 for an increase of 1 kg in birth weight (p= 0.02) for women. For men there was a non-significant decrease of 1.2 ml/min/1.73m2 for an increase of 1 kg in birth weight (p=0.6). Conclusion Women aged 41-52 years with low birth weight had significantly lower measured GFR as compared with participants with normal birth weight, there was no difference for men.

Intrauterine growth restriction, preterm birth and risk of end-stage renal disease during the first 50 years of life

Background Low birth weight (LBW) is associated with a higher risk of end-stage renal disease (ESRD). The relative impacts of absolute birth weight, birth weight in relation to gestational age and preterm birth are, however, uncertain. Methods The Medical Birth Registry of Norway has since 1967 recorded data on all births. All patients with ESRD since 1980 have been registered in the Norwegian Renal Registry. Data from these registries were linked. All individuals registered in the Medical Birth Registry were included and the development of ESRD was used as endpoint in Cox regression statistics. LBW and LBW for gestational age [small for gestational age (SGA)] according to the 10th percentiles were used as the main predictor variables. Results Of the 2 679 967 included subjects, 1181 developed ESRD. Compared with subjects without LBW, subjects with LBW had an adjusted hazard ratio (aHR) for ESRD of 1.61 (1.38–1.98). SGA had an aHR of 1.44 (1.22– 1.70). Further analyses showed that as compared with subjects who had none of the risk factors LBW, SGA and preterm birth, subjects with one risk factor had an aHR of 1.05 (0.84–1.31), subjects with two risk factors had an aHR of 1.67 (1.40–1.98) and subjects with three risk factors had an aHR of 2.96 (1.84–4.76). Conclusions We conclude that LBW was associated with increased risk for ESRD during the first 50 years. Our analyses add to previous knowledge showing that only subjects with at least two of the risk factors LBW, SGA or preterm birth have increased risk.

Improving maternal healthcare in Georgia

Improvement of reproductive health is a worldwide priority. Maternal and perinatal mortality and morbidity are frequently used as measure of quality of the healthcare. Thus, reduction of maternal morbidity and mortality are important goal for the SDGs. Hence, maternal and new-borns health are crucial to report accurately. The key requirement for progress is to have as much precise data as it is possible. Several tools are developed for quality surveillance; among them is the medical birth registry. Georgia is a developing country which recently had healthcare in transition. Over the last decade, Georgia’s health sector has improved quality and embraced evidence-based medicine. Transformation and progress attributed reproductive healthcare. Country elaborated strategic plan and set achievable target for maternal and children’s mortality ratios for 2030. Georgia developed national maternal surveillance system. However, country has been lacking precise, comprehensive, and longitudinal data dealing with the reproductive health. Thus far, data on associated health services mainly derived from the sporadic on-demand surveys. Routine info on mortality and morbidity were available as aggregated data with a lack of epidemiological analysis. In order to provide proper reproductive health profile, Georgia created a nationwide medical birth registry (GBR). GBR has made it possible to create a precise epidemiological analysis and to ensure the evidence-based reporting. To improve epidemiological research capacity, PhD projects were implemented a year after the GBR started operation, in the frame of cooperation of Norwegian and Georgian Universities. Moreover, universities initiated tracks for master students to have internship and graduate thesis in GBR related topics. Overarching goals of the GBR are numerous. Although compilations of statistics and ensuring scientific bases for advice through generated researches are beneficial for universities and country as well. Key messages Studies, based on transparency of highly accurate medical statistics gives possibility for effective implementation of evidence-based public health interventions. Recommendations provided by registry based studies have a pivotal role in formulation and revision of relevant public health strategies.