OBJECTIVE: To investigate the association between parity and urinary incontinence, including subtypes and severity of incontinence, in an unselected sample, with special emphasis on age as a confounder or effect modifier. METHODS: This was a cross-sectional study (response rate 80%) with 27,900 participating women. Data on parity and urinary leakage, type, frequency, amount, and impact of incontinence were recorded by means of a questionnaire. A validated severity index was used. Relative risks (RR) with nulliparous women as reference were used as an effect measure. RESULTS: Incontinence was reported by 25% of participants. Prevalences among nulliparous women ranged from 8% to 32%, increasing with age. Parity was associated with incontinence, and the first delivery was the most significant. The association was strongest in the age group 20-34 years with RR 2.2 (95% confidence interval [CI] 1.8, 2.6) for primiparous women and 3.3 (2.4, 4.4) for grand multiparous women. A weaker association was found in the age group 35-64 years (RRs between 1.4 and 2.0), whereas no association was found among women over 65 years. For stress incontinence in the age group 20-34 years, the RR was 2.7 (2.0, 3.5) for primiparous women and 4.0 (2.5, 6.4) for grand multiparous women. There was an association with parity also for mixed incontinence, but not for urge incontinence. Severity was not clinically significantly associated with parity. CONCLUSION: Parity is an important risk factor for female urinary incontinence in fertile and peri- and early postmenopausal ages. Only stress and mixed types of incontinence are associated with parity. All effects of parity seem to disappear in older age.
Epidemiologic data were analyzed for a total of 2,693 infants with esophageal atresia registered in nine congenital malformation registries around the world. The average recorded prevalence at birth was 2.6 per 10,000 births, with a significant variability among programs--and sometimes within a program--and a maximum prevalence of above 3 per 10,000 births. Clusters of infants with esophageal atresia were observed but may be random. An increasing rate was seen during the period 1965 to 1975 (Norway, South America, Sweden). The type of esophageal atresia was specified in only 439 cases, but no major differences were seen in the epidemiologic characteristics of infants with the most common type (distal fistula) and infants with other types. There was an excess of low birth weight and preterm birth, and infants with esophageal atresia had a birth weight 500 to 1,000 g less than normal infants in each gestational week. There was an excess of twins, apparently mainly or exclusively due to monozygotic twinning, but in only two pairs did both twins have esophageal atresia. There was no effect seen of maternal age, but low parity, irrespective of maternal age, was associated with an increased risk for esophageal atresia. Infant survival varied among programs and depended heavily on associated malformations. Among 1,107 sibs born before the proband and 385 born after the proband, only 25 (1.7%) had a serious malformation; three had esophageal atresia. In 57.3% of the infants with esophageal atresia, no other malformations were present, in 36.4% other major malformations were recorded, and in 6.3% there were chromosomal anomalies. The malformations present associated with esophageal atresia were analyzed: a large proportion entered the constellation sometimes called "caudal mesoderm spectrum of malformations": VATER, Potter, and caudal regression sequences.
OBJECTIVES: To look at the occurrence of arthrogryposis multiplex congenita in newborn of mothers with myasthenia gravis (MG) and factors connected to this. MATERIAL AND METHODS: We retrospectively studied 176 births by 79 MG mothers, recorded in the Medical Birth Registry of Norway (MBRN). Four (2.2%) newborns (including one pair of twins) born with severe skeletal anomalies were identified. RESULTS: All four children died. Three had findings consistent with arthrogryposis multiplexa congenita (AMC), one had a fetal akinesia deformation sequence (FADS). The mother of the child with FADS had previously given birth to a child with neonatal MG. She was now in complete MG remission. The mother of the twins with AMC later gave birth to a child with neonatal MG. CONCLUSION: Siblings of an affected child -- either with neonatal MG or AMC -- have an increased risk to develop either neonatal MG or AMC. As this appears to be independent of the MG mother's clinical state, it is important to discuss previous pregnancy outcomes with all female MG patients.
Women with myasthenia gravis (MG) have an increased risk of complications and adverse pregnancy outcome. This study has examined if this is true also for asymptomatic MG. Using data from the Medical Birth Registry of Norway, births of women prior to receiving an MG diagnosis or in complete clinical MG remission were compared with all non-MG births in Norway in the same period (1967-2000). Forty-nine births occurred in 37 women, 11 of them in clinical remission, and six thymectomized. The perinatal mortality was increased (P = 0.02) and induction of birth (P = 0.007) occurred more frequently. Protracted labor occurred more frequently in the target group (P = 0.03). One of the three children that died had Potter's syndrome. Both mothers with children who died were in complete clinical MG remission. One had previously given and one subsequently gave birth to a child with neonatal MG. The results indicate that complications in birth and pregnancy are not only related to clinical MG disease severity but to the underlying immunological dysfunction.
The study compares frequencies of birth defects between immigrant groups and the rest of the Norwegian population in Norway and estimates the influence of consanguinity and socioeconomic factors on these frequencies. The authors studied all 1.56 million births in Norway from 1967 to 1993. Of these, 7,494 children had two Pakistani parents, 84,688 had one Norwegian and one immigrant parent, and 25,891 had two immigrant parents from countries other than Pakistan. The risk of birth defects relative to the Norwegian group was 0.98 (95% confidence interval 0.92-1.03) in the group with one foreign and one Norwegian parent, 1.39 (95% confidence interval 1.22-1.60) in the group with two Pakistani parents, and 1.04 (95% confidence interval 0.95-1.14) in the group with two parents from other foreign countries; 0.1% of the Norwegian and 30.1% of the Pakistani children had parents who were first cousins. There was no difference in risk between children of nonconsanguineous Pakistani parents and the other groups. The relative risk of birth defects among children whose parents were first cousins was about 2 in all groups. Among the Pakistani, 28% of all birth defects could be attributed to consanguinity. Low paternal educational level was associated with a slightly increased risk in the Norwegian group, while independent effects of parental educational levels were not found in any other groups.
Erratum In: Am J Epidemiol 1997 May 15;145(10):957
Between 1972 and 1993 the number of hospitals and maternity homes providing obstetric help in Norway fell from 158 to 67. Most of the decline is explained by the closing down of maternity homes and obstetrical units in small hospitals, partly due to a reduction in number of births and partly to a deliberate drive towards giving birth in larger units. 16 of the 19 counties of Norway contained four or fewer obstetric institutions in 1993. Nevertheless, most of the 60,000 births took place in institutions with between 500 and 2,999 births annually. Births at home accounted for 0.3%, and births during transport for 0.2% of the total in 1990 and 1993.
AIM: To establish whether smoking is an independent risk factor for sudden infant death syndrome (SIDS), if the effect is mainly due to prenatal or postnatal smoking, and the effect of smoking cessation. METHODS: The analyses were based on data from the Nordic epidemiological SIDS study, a case-control study with 244 cases and 869 controls. Odds ratios were computed by conditional logistic regression analysis. RESULTS: Smoking emerged as an independent risk factor for SIDS, and the effect was mainly mediated through maternal smoking in pregnancy (crude odds ratio 4.0 (95% confidence interval 2.9 to 5.6)). Maternal smoking showed a marked dose-response relation. There was no effect of paternal smoking if the mother did not smoke. Stopping or even reducing smoking was beneficial. SIDS cases exposed to tobacco smoke were breast fed for a shorter time than non-exposed cases, and feeding difficulties were also more common. CONCLUSIONS: Smoking is an independent risk factor for SIDS and is mainly mediated through maternal smoking during pregnancy. Stopping smoking or smoking less may be beneficial in reducing the risk of SIDS.
OBJECTIVE: This study investigated the causes of death among patients with myasthenia gravis (MG), with emphasis on respiratory tract and cardiac disease. METHODS: The Norwegian Cause of Death Register contains information on all deaths among Norwegian citizens. In total, 249 deceased patients with MG were identified (1951-2001). These were compared with 1245 controls deceased in the same period and matched for sex and year of birth. RESULTS: The death certificates of patients with MG had a significantly higher occurrence of respiratory tract disease as cause of death than controls (28.1% v 20.9%, p = 0.012). The difference was most pronounced for male patients, for patients dying between 30 and 69 years of age, and for deaths occurring before 1996. For cardiac disease there was a significantly lower occurrence among patients with MG than among controls at 50-69 years of age, for both men (19.4% v 52.0%, p = 0.001) and women (14.6% v 29.6%, p = 0.036). Age and year of death were important determinants for the causes of death, but could not account for the differences between the patients with MG and controls. CONCLUSIONS: This study shows that patients with MG dying between 1951 and 1995 had a higher occurrence of respiratory tract disease listed as cause of death than had a matched control group. The lack of difference after 1995 probably reflects improved treatment of MG and its complications. The reduced occurrence of cardiac disease among patients with MG is probably explained by competing factors (respiratory tract disease) causing death.
OBJECTIVE: We compared trends and current levels of cesarean section delivery by indication in four countries to help us understand factors underlying national differences in obstetric delivery practice and identify pathways to lower cesarean rates. STUDY DESIGN: We carried out a measurement of change in the use of cesarean delivery by indication in Norway, Scotland, Sweden, and the United States during intervals centered on 1980, 1985, and 1990. Indication for cesarean delivery was determined by a standard set of selection rules. RESULTS: The rate of growth of national cesarean section rates dropped significantly between the time periods 1980 to 1985 and 1985 to 1990 in all four countries; in Sweden this led to an actual decline in the cesarean section rate. Fetal distress and previous cesarean section were important contributors to cesarean section growth in three of the countries in 1980 to 1985, but their contribution to growth dropped off sharply in 1985 to 1990. By the 1990 interval, the overall rate ranged from 24% (United States) to 11% (Sweden), and all four countries had similar cesarean section rates for breech presentation, fetal distress, and "other" indications. Cesarean section deliveries for previous cesarean section and dystocia accounted for the substantially higher U.S. cesarean section rate. CONCLUSIONS: Cesarean section rates are approaching stability in the four countries and have declined in Sweden. Previous cesarean delivery and dystocia may be the major sources of future reductions in the U.S. cesarean rate. The Swedish example shows that it is possible to reduce a relatively low national cesarean section rate.
AIM: To study circadian variation in the sudden infant death syndrome (SIDS) and possible associations with risk factors for SIDS. METHODS: A questionnaire-based case-control study matched for place of birth, age and gender was conducted in Denmark, Norway and Sweden: The Nordic Epidemiological SIDS Study. The study comprised 244 SIDS victims and 869 control infants between September 1992 and August 1995. The main outcome was hour found dead. RESULTS: A significant circadian pattern was observed among the 242 SIDS victims with a known hour found dead, with a peak at 08.00-08.59 in the morning (n = 33). Of the SIDS victims, 12% were found dead at 00.00-05.59, 58% at 06.00-11.59, 21% at 12.00-17.59 and 9.0% at 18.00-23.59. When comparing night/morning SIDS and day/evening SIDS (found dead 00.00-11.59 and 12.00-23.59, respectively), the proportion of night/morning SIDS was high among infants of smoking mothers (81% vs 53%, p