In utero exposure to maternal tobacco smoke and subsequent obesity, hypertension, and gestational diabetes among women in the MoBa cohort

Background: Environmental factors influencing the developmental origins of health and disease need to be identified and investigated. In utero exposure to tobacco smoke has been associated with obesity and a small increase in blood pressure in children; however, whether there is a corresponding increased risk of conditions such as diabetes and hypertension during adulthood remains unclear.Objective: Our goal was to assess the association of self-reported in utero exposure to tobacco smoke with the prevalence of obesity, hypertension, type 2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM) in women 14–47 years of age.Methods: We conducted a cross-sectional analysis of the Norwegian Mother and Child Cohort Study, which enrolled pregnant women in Norway from 1999 thorough 2008. Exposure to tobacco smoke in utero (yes vs. no) was ascertained on the baseline questionnaire (obtained at ~ 17 weeks’ gestation); the outcomes were ascertained from the Medical Birth Registry of Norway and the questionnaire. Our analysis included 74,023 women.Results: Women exposed to tobacco smoke in utero had 1.53 times the odds of obesity [95% confidence interval (CI): 1.45, 1.61] relative to those unexposed, after adjusting for age, education, and personal smoking. After further adjustment for body mass index, the odds ratio for hypertension was 1.68 (95% CI: 1.19, 2.39); for T2DM 1.14 (95% CI: 0.79, 1.65); and for GDM 1.32 (95% CI: 1.10, 1.58) among exposed compared with unexposed.Conclusions: Exposure to tobacco smoke in utero was associated with obesity, hypertension, and GDM in adult women. The possibility that the associations were attributable to unmeasured confounding cannot be excluded.     

Data linkage methods used in maternally-linked birth and infant death surveillance data sets from the United States (Georgia,Missouri, Utah and Washington State), Israel,Norway, Scotland and Western Australia

In this paper we describe the methods used to link birth and infant mortality and morbidity surveillance data sets into sibships using deterministic or multistage probabilistic linkage methods. We describe nine linked data sets: four in the United States (Georgia, Missouri, Utah and Washington State), and four elsewhere (Scotland, Norway, Israel and Western Australia). Norway and Israel use deterministic methods to link births and deaths into sibships. The deterministic linkage is usually dependent on the availability of national identification numbers. In both countries they assign these numbers at birth. Deterministic linkage is usually highly successful, and the major problem is the validation of linkages. In the United States, Western Australia and UK linkage is multistage and probabilistic. This approach is usually dependent on the calculation linkage weights from sociodemographic variables. The success rates of probabilistic methods are above 80%. Maternally-linked perinatal data open new vistas for epidemiological research. Recurrence of poor perinatal outcomes is more appropriately studied using longitudinally-linked data sets. In addition, the emergence of risk factors and the recurrence of risk factors can be studied.     

Survival after peptic ulcer perforation: A time trend analysis

The survival of 1098 patients with ulcer perforation in Norway during the period 1952–1990 was compared with expected survival. Cox regression models incorporating population mortality rates, were used to analyse effects of sex, age, year of birth, and year at risk on excess mortality. Survival was lower in patients than in the general population through a follow-up period of 38 years. Relative survival was lower in women as compared to men, due to more delayed treatment. Long-term survival was lower after praepyloric perforations than after the other perforation types. Relative survival was higher in patients treated 1952–1970 than in those treated more recently. However, adjustment for year of birth revealed a decline in short-term mortality with calendar time, which is in accordance with improved management during the study period. Relative mortality, particularly long-term mortality, was higher in younger birth cohorts, suggesting a shift towards more serious etiologies.     

Measurement of local blood flow in acute myocardial infarction: loss of 15-micron microspheres during the first hour

Distribution of radiolabelled microspheres is widely utilized for determination of regional blood flow in experimental myocardial infarction studies. The purpose of this investigation was evaluation of the microsphere method during 1 h of regional ischaemia. Special attention was focused upon loss of preocclusion microspheres from ischaemic myocardium; mechanisms for loss and blood flow distribution in non-ischaemic left ventricle. Microspheres (15 micron) were injected into the left atrium in nine pentobarbital anaesthetized cats prior to coronary artery occlusion and again after 1 h of occlusion. Preocclusion blood flow estimates were lower in ischaemic compared with non-ischaemic myocardium (1.36 vs. 1.62 cm3 X min-1 X g-1, P = 0.002), corresponding to 16% apparent loss. In endocardial ischaemic tissue, development of oedema could account for the loss. In epicardial ischaemic tissue, oedema was not present and loss was therefore due to migration of microspheres. Epicardial loss increased in proportion to restoration of left ventricular contractility. There was no evidence for significant microsphere loss through lymphatic pathways. In non-ischaemic left ventricular tissue, myocardial blood flow was evenly distributed from apex to base, and also between endocardial and epicardial layers. This study quantitates an important limitation to measurements of local blood flow in ischaemic myocardium by radiolabelled microspheres.     

Estrogen receptor in breast cancer; its relation to mean nuclear area, age and lymph node status

A study of 378 patients with infiltrating breast carcinoma using linear logistic regression and ANOVA analysis demonstrated a different relation between age at operation and estrogen-receptor (ER) concentration in the lymph-node negative and the lymph-node positive groups. Tumours from patients between 51 and 70 years old had lower median ER concentration in the lymph-node negative group than in the lymph-node positive group. In the group older than 70 years, however, tumours from lymph-node negative patients had higher median ER concentrations than those from the lymph-node positive patients. Patients 50 years and younger had similar median ER concentrations in both lymph-node groups. Low mean nuclear area (MNA) of the tumour cells was associated with high frequency of tumours able to produce ER. No such association was found for age. Independent of age and lymph-node status tumours with low MNA also had high ER concentration. These findings suggest that tumours from different lymph-node/age groups may have different biological properties. The relationship between ER and nuclear size point to a key function of the nucleus, both as regards the ability to produce ER and its level of production.     

Changes in frequency and indications for cesarean section in Norway 1967-1984

We have studied the cesarean section frequencies and changing spectrum of indications in Norway during six consecutive 3-year periods from 1967 to 1984. The data set consists of 1,046,162 births notified to the Medical birth registry of Norway, of which 52,426 were specified as cesarean sections, the frequency rising from 1.9% in 1967-69 to 9.7% in 1982-84. A check for completeness of cesarean section notification was made against the birth protocols of the largest obstetrical unit in Norway. The error rate was about 3%. Information on the indication for performing cesarean section was missing in 11.4% of the cases. We grouped thirty-one specified indications under seven headings. In 1967-69 the operation was most often performed for 'maternal' reasons, followed by 'mechanical', 'abnormalities of fetal presentation' and 'acute placental' conditions. Throughout the study period, 'mechanical' (which can also be labelled 'dystocia') accounted for about one third of the indications for cesarean section, while 'maternal' (including high maternal age and pre-eclampsia) and 'acute placental' (placenta praevia and placental abruption) decreased in relative importance. 'Fetal presentation' (including twins) doubled its relative share, while increasing from 2.4 per 1000 births in 1967-69 to 24.8 per 1000 births in 1982-84. A steep rise in the group 'fetal asphyxia' corresponded to the period when the mass of electronic monitoring devices was introduced, in the early 1970s. 'Fetal asphyxia' had a higher relative share of the indications among para 0 mothers than in the total birth population.     

Low birthweight and mortality: the tendency to repeat low birthweight and its association with early neonatal and infant morbidity and mortality

Previous studies have demonstrated the tendency to repeat gestational age and birthweight in successive pregnancies and that this tendency is associated with infant survival. Thus, newborn outcome and survival is less favourable if the gestational age and size departs from this maternal tendency. This paper aims to study diseases or conditions that might be associated with this effect. Data were provided through a linkage between three Danish health registries: the Danish Fertility Database, the National Hospital Registry, and the Registry for Preventive Medicine. Such linkage was possible due to the use of unique ID-person numbers. The study included all 8219 second-order low-birthweight (LBW) singleton Danish births, 1980-94, of whom 7811 were liveborn. It was also required that the mother's first delivery took place during that period. The analysis considered 7803 of these births; eight were excluded due to insufficient information. Of the second-order LBW children, 26% had an elder sibling who was also LBW. Early neonatal mortality of a 'non-repeat' LBW birth was 1.3 times higher than 'repeat' LBW births [53.8 vs. 41.2 per 1000; RR 1.31; 95% CI 1.03, 1.65], as was infant mortality [78.4 vs. 60.8 per 1000; RR 1.30; 95% CI 1.06, 1.56]. Also, proportionately more LBW repeat births had Apgar scores of >or=7 after 1 and 5 min. Overall, repeat second-order LBW babies weighed 68 g more than non-repeat LBW babies (P < 0.001). At term, the weight difference was 160 g higher among repeat LBW births (P < 0.001). The mean number of hospitalisations during the first year of life was lower among repeat than non-repeat LBW babies (2.30 vs. 2.46, P < 0.001), while the mean duration of stay was 23.71 vs. 23.97 days (P > 0.05). Newborn immaturity was the most common diagnosis for hospitalisation, and infections the second most common. There were no differences between repeat and non-repeat LBW births in the proportion with each diagnosis. Apart from the differences in birthweight, we were unable to explain the improved survival for repeat compared with non-repeat LBW babies. Except for differences in Apgar scores, we observed no differences in morbidity based on registered hospitalisations during infancy.