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Biomedical subjects

Sven Cnattingius

Publications and source records attributed to Sven Cnattingius.

At least 55 records · Page 3Linked to original sources
PubMed2003

Parity and risk of subarachnoid hemorrhage in women: a nested case-control study based on national Swedish registries.

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) is the only type of stroke with female predominance, suggesting that reproductive factors may play a role in the etiology. We conducted a population-based study to examine the influence of parity on the risk of SAH in women. METHODS: We linked data from 3 national Swedish registries to identify first-ever hospitalizations for SAH in a cohort of women followed up since first childbirth during 1973-1997. Within this cohort, we conducted a nested case-control study and estimated the odds ratio (OR) and 95% CI of SAH by parity adjusted for age, calendar period, and length of follow-up. Information on smoking habits before the subject's first childbirth was available in a subset of the data (women with first childbirths during 1982-1997). RESULTS: Of the 887 cases identified, 70% had suffered from SAH > or =5 years after giving birth to their last child. The OR declined with increasing parity (1 child: reference; 2: OR=0.83 [95% CI, 0.70 to 0.99]; 3: OR=0.72 [95% CI, 0.58 to 0.91]; 4: OR=0.72 [95% CI, 0.48 to 1.08]; > or =5: OR=0.67 [95% CI, 0.32 to 1.41]). Adjusting for daily cigarette consumption before first childbirth in the subsample in which this information was available reduced but did not eliminate the association of the disorder with parity. CONCLUSIONS: Parity may confer a moderate long-term protective effect on the risk of SAH. The biological mechanism underlying this association is currently unknown.

Adolescent↗
PubMed2003

Mortality and cancer incidence among individuals with Down syndrome.

BACKGROUND: Individuals with Down syndrome (DS) have a predisposition to leukemia and possibly other cancers and excess mortality from other conditions, but information on the magnitude of risk associated with specific cancers or causes of death is sparse. METHODS: Mortality experience and cancer incidence were evaluated in a combined cohort of 4872 individuals with a hospital discharge diagnosis of DS in Sweden (1965-1993) or Denmark (1977-1989) by linkage to national cancer and vital statistics registries. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) were estimated by comparison with age, sex, and calendar-year expected values. RESULTS: Individuals with DS had an increased risk of incident acute lymphocytic (SIR, 24.2; 95% confidence interval [CI], 15.2-36.6; n = 22) and acute nonlymphocytic (SIR, 28.2; 95% CI, 15.7-48.3; n = 14) leukemias. Risks of testicular cancer (SIR, 3.7; 95% CI, 1.0-9.4; n = 4) and liver cancer (SIR, 6.0; 95% CI, 1.2-17.5; n = 3) were also elevated. Individuals with DS also experienced elevated mortality attributed to stomach cancer (SMR, 6.4; 95% CI, 1.7-16.4; n = 4), dementia and Alzheimer disease (SMR, 54.1; 95% CI, 27.9-94.4), epilepsy (SMR, 30.4; 95% CI, 13.9-57.7), ischemic heart disease (SMR, 3.9; 95% CI, 2.7-5.4), other heart disease (SMR, 16.5; 95% CI, 11.0-23.7), cerebrovascular disease (SMR, 6.0; 95% CI, 3.5-9.6), infectious diseases (SMR, 12.0; 95% 6.0-21.4), and congenital anomalies (SMR, 25.8; 95% CI, 21.0-31.4). CONCLUSIONS: Individuals with DS have a substantially increased risk of mortality due to specific causes and may have an elevated risk of other incident cancers in addition to leukemia. These results provide clues regarding chromosome 21 gene involvement in diseases that complicate DS and are important for disease detection and care of affected individuals.

Adolescent↗
PubMed2003

Abortions and breast cancer: record-based case-control study.

It has been suggested that abortions leave the breast epithelium in a proliferative state with an increased susceptibility to carcinogenesis. Results from previous studies of induced or spontaneous abortions and risk of subsequent breast cancer are contradictory, probably due to methodological considerations. We investigated the relationship between abortions and subsequent breast cancer risk in a case-control study using prospectively recorded exposure information. The study population comprised women recorded in the population-based Swedish Medical Birth Register between 1973-91. Cases were defined by linkage of the birth register to the Swedish Cancer Register and controls were randomly selected from the birth register. From the subjects' antenatal care records we abstracted prospectively collected information on induced and spontaneous abortions, as well as a number of potential confounding factors. Relative risk of breast cancer was estimated by odds ratios (OR) with 95% confidence intervals (95% CI). A reduced risk of breast cancer was observed for women with a history of at least 1 compared to no abortions (adjusted OR = 0.84, 95% CI = 0.72-0.99). The adjusted OR decreases step-wise with number of abortions to 0.59 (95% CI = 0.34-1.03) for 3 or more compared to no abortions. The patterns are similar for induced and spontaneous abortions. In conclusion, neither a history of induced nor spontaneous abortions is associated with an increased risk of breast cancer. Our data suggest a protective effect of pregnancies regardless of outcome.

Abortion, Induced↗
PubMed2003

Polybrominated diphenyl ethers in breast milk from Uppsala County, Sweden.

The breast milk concentrations of polybrominated diphenyl ethers (PBDEs; sum of five congeners: BDE-47, -99, -100, -153, and -154) were determined (by GC-ECD) in samples from 93 primiparous women collected from 1996 to 1999 in Uppsala County, Sweden. Dietary and lifestyle factors were also recorded. The mean PBDE concentration was 4.0 ng/g fat and the distribution of samples was skewed with few high values (maximum 28.2 ng/g fat). BDE-47 was the major congener and constituted 59% of the mean concentration of PBDEs. No significant relationship was found between breast milk concentrations of PBDEs and dietary intake of PBDE, age, body mass index, alcohol consumption, or computer usage. After adjustments for these factors, a weak but significant association between PBDE concentrations and smoking was observed. The dietary intake of PBDE for these women was estimated at 27 ng/day, of which fish contributed almost half. After inclusion of 31 additional samples, collected from 2000 to 2001, time trends were studied. The changes in breast milk PBDE levels between 1996 and 2001, similar to the results from another Swedish study on milk from Stockholm mothers, suggest a peak in PBDE concentrations around 1998 and thereafter decreasing levels. However, far-reaching conclusions about PBDE time trends in milk cannot be drawn from this short study.

Adult↗
PubMed2003

The influence of interpregnancy interval on the subsequent risk of stillbirth and early neonatal death.

OBJECTIVE: To study whether interpregnancy interval is associated with increased risks of stillbirth and early neonatal death and whether this possible association is confounded by maternal characteristics and previous reproductive history. METHODS: In a Swedish nationwide study of 410,021 women's first and second singleton deliveries between 1983 and 1997, we investigated the influence of interpregnancy interval on the subsequent risks of stillbirth and early neonatal death. Odds ratios (ORs) with 95% confidence intervals (CIs) estimated using unconditional logistic regression were adjusted for maternal characteristics and previous pregnancy outcome categorized into stillbirth, early neonatal death, preterm, or small for gestational age delivery. RESULTS: Compared with interpregnancy intervals between 12 and 35 months, very short interpregnancy intervals (0-3 months) were, in the univariate analyses, associated with increased risks of stillbirth and early neonatal death (crude OR 1.9; 95% CI 1.3, 2.7; and 1.8; 1.2, 2.8, respectively). However, after adjusting for maternal characteristics and previous reproductive history, women with interpregnancy intervals of 0 to 3 months were not at increased risks of stillbirth (adjusted OR 1.3; 95% CI 0.8, 2.1) or early neonatal death (adjusted OR 0.9; 95% CI 0.5, 1.6). Women with interpregnancy intervals of 72 months and longer were at increased risk of stillbirth (adjusted OR 1.5; 95% CI 1.1, 2.1) and possibly early neonatal death (adjusted OR 1.3; 95% CI 0.9, 2.1). CONCLUSION: Short interpregnancy intervals appear not to be causally associated with increased risk of stillbirth and early neonatal death, whereas long interpregnancy intervals were associated with increased risk of stillbirth and possibly early neonatal death.

Adult↗
PubMed2003

Signs of infection in Pap smears and risk of adverse pregnancy outcome.

Previous studies on whether signs of infection in Pap smears imply a risk factor for preterm delivery are conflicting. In a large population-based study, we combined information from the Swedish Medical Birth Register and the Swedish Pap Smear Screening Register to investigate whether signs of infection in Pap smears increase the risks of adverse pregnancy outcomes. Logistic regression analyses were used to estimate odds ratios (OR) for antepartum death, preterm or small-for-gestational-age delivery. The presence of Coccobacilli or Trichomonas vaginalis in Pap smears increased the risk of small-for-gestational-age delivery (OR 1.3 and 1.4, respectively). Signs of infection in Pap smears were generally not associated with an increased risk of antepartum death or preterm birth. However, the presence of Coccobacilli in Pap smears within 4 weeks before delivery was associated with a more than fourfold increase in risk of very preterm delivery (< or =31 weeks, OR 4.7). This indicates that if Coccobacilli are detected in Pap smears during the second trimester, antibacterial treatment may lower the risk of very preterm delivery.

Adolescent↗
PubMed2003

Adverse pregnancy outcomes in snuff users.

OBJECTIVE: The purpose of the study was to evaluate the effects of smokeless tobacco use during pregnancy. STUDY DESIGN: We examined birth weight, preterm delivery, and preeclampsia in women who were delivered of singleton, live-born infants in Sweden from 1999 through 2000. For each snuff user, 10 cigarette smokers and 10 tobacco nonusers were selected randomly. RESULTS: After exclusions, 789 snuff users, 11,240 smokers, and 11,495 nonusers remained. Compared with nonusers, adjusted mean birth weight was reduced in snuff users by 39 g (95% CI, 6-72 g) and in smokers by 190 g (95% CI, 178-202 g). Preterm delivery was increased in snuff users and smokers (adjusted odds ratios, 1.98 [95% CI, 1.46-2.68] and 1.57 [95% CI, 1.38-1.80], respectively). Preeclampsia was reduced in smokers (adjusted odds ratio, 0.63; 95% CI, 0.53-0.75) but increased in snuff users (adjusted odds ratio, 1.58; 95% CI, 1.09-2.27). CONCLUSION: Snuff use was associated with increased risk of preterm delivery and preeclampsia. Snuff does not appear to be a safe alternative to cigarettes during pregnancy.

Birth Weight↗
PubMed2003

Birthweight differences between USA and China and their relevance to breast cancer aetiology.

BACKGROUND: There has been renewed interest about determinants of birth size following the propagation of hypotheses that birth size parameters may have long-term consequences on the occurrence of common diseases in adulthood, including breast cancer. METHODS: In the context of a cohort study, 296 Caucasian pregnant women in Boston, USA and 329 Chinese pregnant women in Shanghai, China were followed to term. Birth size characteristics of the baby and maternal anthropometry were measured using standardized protocols. Analyses were conducted through multiple regression procedures. RESULTS: No significant difference was found between US and Chinese newborns with respect to gestational age. Among US women, pregravid oral contraceptive use was strongly associated with higher birthweight. In both US and Chinese women, birthweight was positively associated with height, pre-pregnancy body mass index, and weight gain during pregnancy. More importantly, the difference in these three maternal variables between the two samples fully explains the birthweight difference between the two populations. CONCLUSIONS: We postulate that babies in China may have lower birthweight because their mothers' anthropometry imposes constraints on the growth of the fetus. When Chinese women migrate to the US, they tend to grow taller and heavier so that their babies can reach, on the average, a higher birthweight. The recurrence of this process in successive generations could explain why eventually Chinese Americans tend to have comparable birth and adult anthropometric characteristics, as well as comparable breast cancer rates, to those of Caucasian Americans.

Adolescent↗
PubMed2003

Time of birth and risk of intrapartum and early neonatal death.

BACKGROUND: Previous studies have found that infants born at night and during weekends and holidays have an increased risk of perinatal mortality. However, these associations may be confounded by the distribution of high-risk deliveries according to time of birth. METHODS: We undertook a population-based cohort study of 694,888 singleton births without elective cesarean section in Sweden between 1991 and 1997. We estimated relative risks of intrapartum and early neonatal death according to the hour, day and month of delivery. Estimated risk ratios were adjusted for gestational age, birth weight for gestational age, malformations, induction of labor, breech presentations and year of birth. RESULTS: Infants of high-risk deliveries were more often delivered during daytime (8:00 am to 7:59 pm). Compared with infants born during daytime, infants born at night were at increased risk of early neonatal death (adjusted risk ratio = 1.28; 95% confidence interval = 1.13-1.46), but not intrapartum death (1.05; 0.71-1.54). If this association is causal, 12% of early neonatal deaths can be attributed to the increased risk among nighttime births. There was no association of weekend or holiday births with risks of intrapartum or early neonatal death. CONCLUSIONS: Infants born at night may be at increased risk of early neonatal death.

Cohort Studies↗
PubMed2003

Cigarette smoking and the risk of gestational and pregestational diabetes in two consecutive pregnancies.

OBJECTIVE: Cigarette smoking during pregnancy may increase the risk of gestational diabetes mellitus (GDM) or pregestational diabetes mellitus (PDM). Smoking has been associated positively with hyperinsulinemia and insulin resistance in experimental studies, although the association with diabetes remains unclear. To further explore this issue, we examined the association with smoking in the largest prospective cohort study of GDM and PDM to date. RESEARCH DESIGN AND METHODS: The study population comprised 212190 women in the population-based Swedish Birth Registry who had their first and second deliveries between January 1987 and December 1995. Maternal characteristics were recorded in a standardized manner at the first prenatal visit, followed by a clinical examination and a standardized in-person interview to assess lifestyle habits. Women were categorized as nonsmokers, light smokers (one to nine cigarettes per day), or moderate-to-heavy smokers (at least 10 cigarettes per day). RESULTS: Women with GDM in their first pregnancy experienced an eight- to ninefold increased risk of GDM or PDM in their second pregnancy. Cigarette smoking was not associated with increased risk of these conditions. Neither women who smoked during their first and second pregnancies nor those who commenced smoking between pregnancies had a higher risk of GDM or PDM than nonsmokers. CONCLUSIONS: Our findings do not support an association between cigarette smoking and risk of GDM or PDM in young women of childbearing age.

Adult↗
PubMed2003

Maternal lung cancer and testicular cancer risk in the offspring.

It has been hypothesized that smoking during pregnancy could increase the offspring's risk for testicular cancer. This hypothesis is indirectly supported by both ecological studies and studies of cancer aggregations within families. However, results from analytical epidemiological studies are not consistent, possibly due to methodological difficulties. To further study the association between smoking during pregnancy and testicular cancer, we did a population-based cohort study on cancer risk among offspring of women diagnosed with lung cancer. Through the use of the Swedish Cancer Register and the Swedish Second-Generation Register, we identified 8,430 women who developed lung cancer between 1958 and 1997 and delivered sons between 1941 and 1979. Cancer cases among the male offspring were then identified through the Swedish Cancer Register. Standardized incidence ratios were computed, using 95% confidence intervals. We identified 12,592 male offspring of mothers with a subsequent diagnosis of lung cancer, and there were 40 cases of testicular cancer (standardized incidence ratio, 1.90; 95% confidence interval, 1.35-2.58). The association was independent of maternal lung cancer subtype, and the risk of testicular cancer increased stepwise with decreasing time interval between birth and maternal lung cancer diagnosis. Our results support the hypothesis that exposure to cigarette smoking in utero increases the risk of testicular cancer.

Adult Children↗
PubMed2003

Serum insulin-like growth factors in normal pregnancy and in pregnancies complicated by preeclampsia.

BACKGROUND: Lower levels of insulin-like growth factor I (IGF-I) have been shown to be associated with preeclampsia and also with a reduced risk of breast cancer later in life. Lower levels of IGF before clinical signs of preeclampsia could be one possible mechanism in the etiology of preeclampsia as well as for the reduced risk of breast cancer associated with preeclampsia. We have prospectively investigated maternal serum levels of IGF-I, IGF-II, and the main binding protein insulin-like growth factor binding protein 3 (IGFBP-3) in women with and without preeclampsia. METHODS: We used maternal serum samples from a Swedish-Norwegian cohort study obtained in the 17th and 33rd gestational week from 30 women who subsequently developed preeclampsia and 128 women who did not develop preeclampsia. RESULTS: There were no significant differences in serum concentrations IGF-I and IGFBP-3 in the 17th or the 33rd week of gestation between women who developed preeclampsia or not. Compared with nonpreeclamptic women, preeclamptic women had significantly higher serum levels of IGF-II in week 33, but there was no difference in week 17. CONCLUSION: In women who developed preeclampsia, we found no support for the hypothesis that the disease was preceded by lower serum levels of IGF-I and IGF-II, or higher serum levels of IGFBP-3. However, among women who later developed preeclampsia, serum levels of IGF-II were significantly higher in the 33rd gestational week.

Adult↗
PubMed2002

Women with schizophrenia: pregnancy outcome and infant death among their offspring.

Schizophrenia in the mother may imply an increased risk of adverse pregnancy outcome. However, inconclusive findings, unknown pathological mechanisms and possible confounding by social factors and smoking requests further explorations. The aim of this study were to (1) examine non-optimal pregnancy outcome using data from a population-based cohort, controlling for covariates known to influence fetal growth; and (2) perform separate analyses of women diagnosed before childbirth and women hospitalized for schizophrenia during pregnancy. The study sample comprised 2096 births by 1438 mothers diagnosed with schizophrenia (of whom 696 mothers were antenatal diagnosed and 188 admitted during pregnancy) and 1,555,975 births in the general population. We found significantly increased risks for stillbirth, infant death, preterm delivery, low birth weight, and small-for-gestational-age among the offspring of women with schizophrenia. Women with an episode of schizophrenia during pregnancy had the highest risks (e.g., low birth weight; OR 4.3, 95% CI 2.9-6.6 and stillbirth; OR 4.4, 95% CI 1.4-13.8). Controlling for a high incidence of smoking during pregnancy among schizophrenic women (51% vs. 24% in the normal population) and other maternal factors (single motherhood, maternal age, parity, maternal education, mothers' country of birth and pregnancy-induced hypertensive diseases) in a multiple regression model, reduced the risk estimates markedly. However, the risks for adverse pregnancy outcomes were even after adjustments generally doubled for women with an episode of schizophrenia during pregnancy compared to women in the control group (e.g., low birth weight; OR 2.3, 95% CI 1.5-3.5, preterm delivery; OR 2.4, 95% CI 1.5-3.8 and stillbirth; OR 2.5, 95% CI 0.8-7.9). The risks for preterm delivery and low birth weight were significantly elevated throughout the analyses. We conclude that schizophrenia in the mother implies an increased risk for poor perinatal outcome, not fully explained by maternal factors, and a need to consider a common familial (probably genetic) vulnerability for pre- and perinatal stress and schizophrenia.

Adult↗
PubMed2002

Plasma folate levels and risk of spontaneous abortion.

CONTEXT: Both folate deficiency and folic acid supplements have been reported to increase the risk of spontaneous abortion. The results are inconclusive, however, and measurements of folate have not been available in all studies. OBJECTIVE: To study the association between plasma folate levels and the risk of spontaneous abortion. DESIGN, SETTING, AND POPULATION: Population-based, matched, case-control study of case women with spontaneous abortion and control women from January 1996 through December 1998 in Uppsala County, Sweden. Plasma folate measurements were available for 468 cases and 921 controls at 6 to 12 gestational weeks. MAIN OUTCOME MEASURE: Risk of spontaneous abortion vs maternal plasma folate level. RESULTS: Compared with women with plasma folate levels between 2.20 and 3.95 ng/mL (5.0 and 8.9 nmol/L), women with low (< or =2.19 ng/mL [< or =4.9 nmol/L]) folate levels were at increased risk of spontaneous abortion (adjusted odds ratio [OR], 1.47; 95% confidence interval [CI], 1.01-2.14), whereas women with higher folate levels (3.96-6.16 ng/mL [9.0-13.9 nmol/L] and > or =6.17 ng/mL [> or =14.0 nmol/L]) showed no increased risk of spontaneous abortion (OR, 0.84; 95% CI, 0.59-1.20; and OR, 0.74; 95% CI, 0.47-1.16, respectively). Low folate levels were associated with a significantly increased risk when the fetal karyotype was abnormal (OR, 1.95; 95% CI, 1.09-3.48) but not when the fetal karyotype was normal (OR, 1.11; 95% CI, 0.55-2.24) or unknown (OR, 1.45; 95% CI, 0.90-2.33). CONCLUSION: Low plasma folate levels were associated with an increased risk of early spontaneous abortion.

Abortion, Spontaneous↗
PubMed2002

Effect of caffeine exposure during pregnancy on birth weight and gestational age.

Epidemiologic studies have been unable to conclusively evaluate whether caffeine intake during pregnancy is associated with reduced birth weight and/or fetal growth restriction. The authors conducted a prospective, population-based cohort study to investigate the effect of caffeine on birth weight, gestational age, and birth weight standardized for gestational age (birth weight ratio). Of 953 women recruited in early pregnancy in Uppsala County, Sweden, from 1996 to 1998, 873 women delivering liveborn singleton infants were included in the analysis. Caffeine exposures were ascertained from in-person interviews at 6-12 and 32-34 completed gestational weeks, and maternal plasma was analyzed for cotinine levels as an indicator of smoking. Analysis of variance was used to estimate the effect of caffeine on birth weight, gestational age at delivery, and birth weight ratio after accounting for the effects of other covariates, such as maternal sociodemographic characteristics, plasma cotinine, and pregnancy symptoms. There were no associations between caffeine consumption and birth weight, gestational age, and birth weight ratio, neither when caffeine exposure was averaged from conception to the 32nd to 34th gestational weeks, nor when caffeine exposure was stratified by trimesters of pregnancy. These results do not support an association between moderate caffeine consumption and reduced birth weight, gestational age, or fetal growth.

Adult↗
PubMed2002

Perinatal exposure to infection and risk of childhood leukemia.

BACKGROUND: A population-based case-control study was conducted to investigate the association between childhood leukemia and infectious exposures during pregnancy and early neonatal period. PROCEDURE: Children born and diagnosed with leukemia between 1973 and 1989 in Sweden (578 lymphatic, 74 myeloid) were selected as cases. One control was randomly selected for each case and individually matched by sex, month, and year of birth. Children with Down's syndrome were excluded. Exposure data were blindly abstracted from antenatal, obstetric, and other standardized medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression. RESULTS: A history of maternal infection was not significantly associated with childhood leukemia, OR = 1.25 (95% CI 0.95-1.65). Maternal lower genital tract infection significantly increased the risk of childhood leukemia, OR = 1.78 (95% CI 1.17-2.72), and especially for children over 4 years of age at diagnosis, OR = 2.01 (95% CI 1.12-3.80). Neonatal infection was not associated with the risk of leukemia. The results remained unaltered after adjustment for potential confounders, and separate analyses for myeloid and lymphoid leukemia. CONCLUSIONS: We could document an association between exposure to maternal lower genital tract infection in utero, and a subsequent risk for childhood leukemia, which indicate the importance of an early exposure.

Acute Disease↗