Maternal alcohol and coffee drinking, parental smoking and childhood leukaemia: a French population-based case-control study

We investigated the role of maternal alcohol and coffee drinking during pregnancy and that of parental smoking in the aetiology of childhood leukaemia. A French, population-based, case-control study was conducted, comparing 472 [407 acute lymphoblastic leukaemia (ALL) and 62 acute myeloblastic leukaemia] cases of childhood acute leukaemia (AL) and 567 population controls, frequency-matched with cases on age, gender and region of residence. Both case and control mothers filled in a comprehensive self-administered standardised questionnaire, eliciting detailed data on maternal alcohol and coffee consumption during pregnancy and parental smoking before, during and after pregnancy. Maternal alcohol consumption of more than 1 drink per day was related to ALL (OR = 2.8 [95% CI 1.8, 5.9]). While maternal coffee consumption was not significantly related to AL (OR = 1.4 [95% CI 0.9, 2.3]), highest intake of coffee (more than 3 cups per day) during pregnancy was associated with AL in children whose mothers were non-smokers (OR = 1.9 [95% CI 1.0, 3.5]). No association with parental smoking, either maternal or paternal, was observed with AL. The present results suggest a possible role of the highest consumption of alcohol by the mother during pregnancy in the aetiology of childhood AL.     

Maternal smoking during pregnancy and the risk of congenital urinary tract anomalies.

To study maternal smoking during pregnancy and the risk of congenital urinary tract anomalies, we interviewed mothers of 118 affected infants born to residents of western Washington State during 1990 and 1991 and mothers of 369 control infants randomly selected from those without birth defects delivered during those years in five hospitals in King County, Washington. Maternal smoking was associated with an increased risk of congenital urinary tract anomalies in offspring (adjusted odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.2, 4.5). This risk was higher among light smokers (1-1000 cigarettes during the pregnancy) (OR = 3.7; 95% CI = 1.7, 8.6) than among heavy smokers (OR = 1.4; 95% CI = 0.6, 3.3). Our results corroborate previous findings and support the hypothesis of a causal relation.     

Determinants of developmental delay in infants aged 12 months

The aim of this study was to determine which demographic, maternal, obstetric and postnatal variables were associated with achievement of developmental milestones at the age of 12 months in term infants. Mothers and babies were enrolled in the Auckland Birthweight Collaborative Study shortly after birth. All infants were full term (gestation >or= 37 weeks). Approximately half of the sample were small for gestational age (SGA = birthweight 10th percentile). A maternal interview was conducted soon after birth. Phase 2 of the study occurred 12 months later when mothers were sent a postal questionnaire requesting information about the child's health and development during the first year of life using the Denver Prescreening Developmental Questionnaire. Seven hundred and forty-four (85.4%) European mothers returned the postal questionnaire. SGA children were not at increased risk of developmental delay at 12 months of age. In a sample representative of New Zealand European children, after adjustment for the effects of potential confounders, maternal smoking during pregnancy (OR = 2.1 [95% CI 1.1, 4.0]), maternal smoking during the first year of life (OR = 1.9 [95% CI 1.0, 3.8]) and low levels of satisfaction with parenting (OR = 2.4 [95% CI 1.1, 5.2]) were associated with significantly increased risk of developmental delay. In the subgroup of SGA children, maternal smoking during pregnancy (OR = 2.9 [95% CI 1.4, 6.2]), high levels of stress associated with parenting (OR = 2.2 [95% CI 1.2, 4.0]), and low levels of satisfaction with parenting (OR = 4.3 [95% CI 1.3, 13.5]) were significantly associated with developmental delay after adjustment for the effects of potential confounders. In conclusion, maternal and postnatal factors were better predictors of developmental delay than demographic variables.     

孕期被动吸烟对妊娠并发症及妊娠结局的影响

目的了解孕期被动吸烟发生情况,并探讨其对妊娠并发症及结局的影响。方法选取2012年4月―2013年3月在我国15家医疗保健机构分娩的8926例单胎活产产妇作为研究对象,使用自制调查问卷收集孕期被动吸烟发生情况、妊娠并发症和结局等信息,采用单因素和多因素Logistic回归分析模型分析孕期被动吸烟对妊娠并发症及结局的影响。结果共1801例产妇在孕期经历被动吸烟。控制混杂因素后,孕期经历被动吸烟的产妇妊娠期糖尿病(gestational diabetes mellitus,GDM)的发生风险是非被动吸烟者的1.359倍(95%CI:1.146~1.612,P<0.001),胎膜早破的风险为1.290倍(95%CI:1.095~1.520,P=0.002),早产的风险为1.367倍(95%CI:1.155~1.619,P<0.001),娩出低出生体重儿的风险为1.341倍(95%CI:1.079~1.668,P=0.008)。与非被动吸烟者相比,平均每周被动吸烟天数≥4天者胎膜早破、早产和低出生体重儿的发生风险分别为非被动吸烟者的1.402倍(95%CI:1.104~1.780,P=0.006)、1.690倍(95%CI:1.339~2.132,P<0.001)和1.584倍(95%CI:1.172~2.141,P=0.023)。结论被调查产妇孕期被动吸烟率较高,孕期经历被动吸烟能够增加妊娠期糖尿病、胎膜早破、早产和低出生体重儿的发生风险。     

Prenatal and intrapartum events and sudden infant death syndrome

The purpose of this study was to evaluate specific pregnancy and labour and delivery events that may increase the risk of sudden infant death syndrome (SIDS). A matched case-control study was conducted in five counties in southern California, using California death certificate records. The sample consisted of 239 Caucasian, African-American, Hispanic and Asian mothers of SIDS infants and 239 mothers of control infants matched on sex, race, birth hospital and date of birth. Mothers participated in a detailed telephone interview and provided access to obstetric and paediatric records. More case than control mothers reported a family history of anaemia (OR=2.12, P < 0.001). Placental abruptions were strongly associated with SIDS (unadjusted OR=7.94, [95% CI 1.34,47.12]). There was an increased risk of SIDS death associated with maternal anaemia during pregnancy (OR=2.51, [95% CI 1.25,5.03]), while simultaneously adjusting for maternal smoking during pregnancy, maternal years of education and age, parity, infant birthweight, gestational age, medical conditions at birth, infant sleep position and post-natal smoking. Interactions of anaemia and prenatal smoking as well as anaemia and post-natal smoking were not statistically significant. There were no other statistically significant differences between case and control mothers for pregnancy conditions, labour and delivery events (e.g. caesarean sections, anaesthesia, forceps) or newborn complications (e.g. nuchal cord, meconium aspiration). Anaemia and placental abruptions were significantly associated with an increased risk of SIDS; both are circumstances in which a fetus may become hypoxic, thereby compromising the subsequent growth, development and ultimate survival of the infant.     

Maternal diet and the risk of hypospadias and cryptorchidism in the offspring

Male genital tract birth defects have been associated in previous studies with several prenatal exposures to environmental and dietary risk factors. The purpose of this study was to explore the association between hypospadias and cryptorchidism, and the dietary habits of an agricultural population in Italy. A population-based case-control study was conducted in the Sicilian Province of Ragusa. Cases (n = 90) and controls (n = 202) included births for the period 1998-2002. Data on dietary habits of the mothers, as well as health-related social, occupational and environmental exposures prior to and during the index birth, were collected through interviews. Adjusted odds ratios (OR) were calculated by logistic regression after adjustment for confounding variables. Increased ORs were observed for mothers of children with hypospadias who, during pregnancy, frequently consumed fish (OR = 2.33 [95% confidence interval (CI) 1.03, 5.31]) and market-purchased fruit (OR = 5.10 [95% CI 1.31, 19.82]). For cryptorchidism, increased risk was observed in mothers consuming liver (OR = 5.21 [95% CI 1.26, 21.50]), and smoked products (OR = 2.46 [95% CI 1.15, 5.29]). For the two malformations pooled together, increased risk was associated with maternal consumption of liver (OR = 4.38 [95% CI 1.34, 14.26]) and with frequent consumption of wine (OR = 1.98 [95% CI 1.01, 3.86]). This study suggests that some maternal dietary factors may play a role in the development of congenital defects of the male reproductive tract. In particular, our data indicate that further research may be warranted on the endocrine-disrupting effects resulting from the bioaccumulation of contaminants (fish, liver), pesticides (marketed fruit, wine) and/or potentially toxic food components (smoked products, wine, liver).     

High caffeine consumption in the third trimester of pregnancy: gender-specific effects on fetal growth

It has been suggested that a high caffeine intake in pregnancy may be a risk factor for fetal growth retardation. We have tested this hypothesis in a population-based case-control study. Caffeine intake among 111 mothers of small-for-gestational-age (SGA) infants (56 boys, 55 girls) was compared with the intake among 747 mothers of non-SGA infants (368 boys, 379 girls). Food records for 3 days were collected in the second (week 17-20) and in the third (week 33) trimester, and caffeine intake from coffee, tea, soft drinks and chocolate was calculated and dichotomised as low or high, based upon the median value. Mothers of SGA infants had higher mean intake of caffeine [281 +/- 210 (SD) mg/day] in the third trimester than mothers of non-SGA infants (212 +/- 150 mg/day; P < 0.001). The risk of SGA birth was nearly doubled if the mother had a high rather than a low caffeine intake in the third trimester [odds ratio (OR) 1.8; 95% confidence intervals (CI) 1.2, 2.5]. The increased risk was mainly found in boys (OR 2.8; 95% CI 1.5, 5.2), and not in girls (OR 1.2; 95% CI 0.7, 2.1). The increased risk for boys persisted after adjustment for cigarette smoking alone, or for smoking and various other SGA risk factors together. Our results suggest that a high caffeine intake in the third trimester may be a risk factor for fetal growth retardation, in particular if the fetus is a boy.     

Active and passive maternal smoking during pregnancy and the risks of low birthweight and preterm birth: the Generation R Study

The objective of this study was to examine the associations between active and passive smoking in different periods of pregnancy and changing smoking habits during pregnancy, with low birthweight and preterm birth. The study was embedded in the Generation R Study, a population-based prospective cohort study from early fetal life onwards in Rotterdam, The Netherlands. Active and passive smoking were assessed by questionnaires in early, mid- and late pregnancy. Analyses were based on 7098 pregnant women and their children. Active smoking until pregnancy was ascertained and was not associated with low birthweight and preterm birth. Continued active smoking after pregnancy was also recorded and was associated with low birthweight (adjusted odds ratio 1.75 [95% CI 1.20, 2.56]) and preterm birth (adjusted odds ratio 1.36 [95% CI 1.04, 1.78]). The strongest associations were found for active maternal smoking in late pregnancy. Passive maternal smoking in late pregnancy was associated with continuously measured birthweight (P for trend <0.001). For all active smoking categories in early pregnancy, quitting smoking was associated with a higher birthweight than continuing to smoke. Tendencies towards smaller non-significant beneficial effects on mean birthweight were found for reducing the number of cigarettes without quitting completely. This study shows that active and passive smoking in late pregnancy are associated with adverse effects on weight and gestational age at birth. Smoking in early pregnancy only, seems not to affect fetal growth adversely. Health care strategies for pregnant women should be aimed at quitting smoking completely rather than reducing the number of cigarettes.     

孕妇被动吸烟与低出生体重关系的Meta分析

目的分析孕妇孕早期和不同孕期被动吸烟对新生儿低出生体重的影响。方法通过Meta分析方法分析孕妇被动吸烟与新生儿低出生体重之间的关系。对NCBI、OVID-MEDLINE、CNKI、VIP以及CBM数据库进行检索(截止日期为2008年4月),结果报告合并OR值及95%CI。结果共获得26篇文献,其中队列研究20篇,病例对照研究6篇。总体分析,孕妇被动吸烟的合并效应值OR=1.65(95%CI:1.39～1.97);调整合并效应值OR=1.60(95%CI:1.25～2.05);最低和最高暴露量的合并效应值分别为OR=1.53(95%CI:1.14～2.04)和OR=2.53(95%CI:1.46～4.36);孕早期暴露的合并效应值OR=1.12(95%CI:0.82～1.55),没有统计学意义。结论孕妇被动吸烟增加新生儿低出生体重的危险性;孕中晚期可能是被动吸烟效应的敏感期;被动吸烟的阈值是否存在尚不明确。     

Maternal and gestational risk factors for hypospadias

BACKGROUND: An increase in the prevalence of hypospadias has been reported, but the environmental causes remain virtually unknown. OBJECTIVES: Our goal was to assess the association between risk of hypospadias and indicators of placental function and endogenous hormone levels, exposure to exogenous hormones, maternal diet during pregnancy, and other environmental factors. METHODS: We conducted a case-control study in Sweden and Denmark from 2000 through 2005 using self-administered questionnaires completed by mothers of hypospadias cases and matched controls. The response rate was 88% and 81% among mothers of cases and controls, respectively. The analyses included 292 cases and 427 controls. RESULTS: A diet during pregnancy lacking both fish and meat was associated with a more than 4-fold increased risk of hypospadias [odds ratio (OR) = 4.6; 95% confidence interval (CI), 1.6-13.3]. Boys born to obese [body mass index (BMI) > or = 30] women had a more than 2-fold increased risk of hypospadias (OR = 2.6; 95% CI, 1.2-5.7) compared with boys born to mothers with a normal weight (BMI = 20-24). Maternal hypertension during pregnancy and absence of maternal nausea increased a boy's risk of hypospadias 2.0-fold (95% CI, 1.1-3.7) and 1.8-fold (95% CI, 1.2-2.8), respectively. Nausea in late pregnancy also appeared to be positively associated with hypospadias risk (OR = 7.6; 95% CI, 1.1-53). CONCLUSIONS: A pregnancy diet lacking meat and fish appears to increase the risk of hypospadias in the offspring. Other risk associations were compatible with a role for placental insufficiency in the etiology of hypospadias.     

Maternal smoking habits and cognitive development of children at age 4 years in a population-based birth cohort

BACKGROUND: Active maternal smoking during pregnancy has been associated with a higher risk of behavioural disorders in children, but a few cohort studies measuring smoking data prospectively have studied its specific effects on the cognitive abilities of pre-schoolers. METHOD: A birth cohort was set up in Menorca Island in 1997 within the Asthma Multicenter Infants Cohort Study. A total of 420 (87% of those eligible) children had complete data for final analyses at age 4 years. Interviewer-administered questionnaires were completed by mothers during the third trimester of pregnancy and then every year up to age 4 years of their child. A standardized version of the McCarthy Scales of Children's Abilities (MCSA) was used to evaluate the child's motor and cognitive capabilities. Multivariable regressions were used with MCSA's assessed outcomes adjusting for: home location, maternal alcohol consumption, mother's social class and level of education during pregnancy, parity, marital status, father's education level, child's gender, birth weight and height, breastfeeding duration, passive smoking, school season, age during test administration and evaluator (psychologist). RESULTS: A high global consistency in maternal smoking habits was found (total agreement = 88.7%). Maternal social class and education level were inversely associated with maternal smoking behaviour. Maternal smoking during pregnancy (in cig./day) was associated with a decrease (in points) of children's global cognitive score [beta = -0.60, (95% CI: -1.10; -0.09)]; as well as global cognitive sub-areas like verbal score [beta = -0.59, (95% CI: -1.11; -0.07)]; quantitative score [beta = -0.57, (95% CI: -1.08; -0.06)]; executive function score [beta = -0.71, (95% CI: -1.23; -0.20)]; and working memory score [beta = -0.46, (95% CI: -0.92; -0.01)]. CONCLUSION: Our findings suggest an association with maternal smoking during pregnancy and lowered cognitive development in children at age 4 years.     

Associations of maternal prenatal smoking with child adiposity and blood pressure

OBJECTIVE: To examine the extent to which maternal prenatal smoking is associated with adiposity, central adiposity, and blood pressure in 3-year-old children. RESEARCH METHODS AND PROCEDURES: We studied 746 mother-child pairs in Project Viva, a prospective cohort study, and categorized mothers as never, early pregnancy, or former smokers. Main outcome measures were overweight (BMI for age and sex > 85th percentile), BMI z-score, sum of subscapular (SS) and triceps (TR) skinfolds, SS:TR skinfold ratio, and systolic blood pressure (SBP). RESULTS: One hundred sixty-one (22%) mothers quit smoking before pregnancy, 71 (10%) smoked in early pregnancy, and 514 (69%) never smoked. At age 3 years, 204 (27%) children were overweight. On multivariable analysis, compared with children of never smokers, children of early pregnancy smokers had an elevated risk for overweight [odds ratio (OR), 2.2; 95% confidence interval (CI), 1.2, 3.9] and higher BMI z-score (0.30 units; 95% CI, 0.05, 0.55), SS + TR (2.0 mm; 95% CI, 0.9, 3.0), and SBP (2.4 mm Hg; 95% CI, -0.1, 4.9). Children of former smokers were not more overweight (BMI z-score, 0.02 units; 95% CI, -0.15, 0.19) but had higher SBP (1.5 mm Hg; 95% CI, -0.1, 3.2). We saw no relationship of smoking with central adiposity (SS:TR). DISCUSSION: Former and early pregnancy smokers had children with somewhat higher SBP, but only early pregnancy smokers had children who were more overweight. Mechanisms linking smoking with child adiposity and blood pressure may differ. A long-term impact of maternal smoking on offspring cardiovascular risk provides further reason to reduce smoking in women.     

West Coast study of childhood brain tumours and maternal use of hair-colouring products

The immature nervous system of the fetus is characterised by rapid cell growth and division and is particularly vulnerable to carcinogens and mutagens. Several epidemiological studies have reported an increased risk for childhood brain tumours (CBT) associated with exposure to N-nitroso compounds (NOC). Hair-colouring products (hair "dyes") that contain NOC-related aromatic amines have shown mutagenicity in vitro and carcinogenic properties in vivo. The potential public health impact of the relationship between hair dye use and carcinogenesis has prompted epidemiological research, given that a large proportion of American women have used hair dyes. A large population-based case-control study was conducted on the west coast of the USA to investigate risk factors for CBT including exposure to NOC. Eligible CBT patients (<20 years of age and diagnosed between 1984 and 1991) were identified from cancer registries in Los Angeles County, the San Francisco Bay Area in California and the Seattle area in Washington state. A total of 540 biological mothers of these children were interviewed, and 801 control subjects who were frequency matched to the CBT patients on birth year and sex were obtained using random digit dialling. Mothers were asked details about personal use of hair dyes during the index pregnancy including frequency of use, trimester of use and type of dye used. Results from age- and sex-adjusted unconditional logistic regression analyses showed no association between risk for CBT and use of hair dyes 1 month before and/or during pregnancy nor during specific trimesters. A nearly twofold increased risk for CBT was associated with single-interval use during the 1 month before pregnancy, but the confidence interval (CI) was imprecise and the estimate was not different from unity (OR = 1.9, 95% CI [0.5, 7.0]). Exclusive use of permanent dye, temporary dye or hair darkeners was not associated with risk for CBT. A twofold increased risk (OR = 2.0, 95% CI [0.83, 4.7]) was observed with exclusive use of semi-permanent dye during the month before or during pregnancy. Exclusive use of semi-permanent dye during the month before pregnancy and/or first trimester also was associated with an elevated risk for CBT, again not different from unity and with an imprecise CI (OR = 2.5, 95% CI = [0.58, 10.3]). There was no evidence of an association between risk for CBT by histological subtypes and use of hair dyes during the index pregnancy or the month before conception. Together with results from previous studies, these results provide no consistent evidence of an association between risk for CBT and use of hair dyes during pregnancy.     

母亲孕前BMI和孕期增重与学龄前儿童超重肥胖的相关性研究

目的探讨母亲孕前体质量指数(BMI)和孕期增重与学龄前儿童超重肥胖的相关性。方法选取2019年1月至2020年1月于余姚市妇幼保健院儿童保健科进行儿童保健咨询的3~5岁儿童共300例为研究对象,回顾性收集母亲孕前BMI和孕期增重情况,采用多因素Logistic回归模型进行相关性分析。结果儿童超重肥胖的发生率为35例(11.67%),在校正性别、年龄等混杂因素后,母亲孕前低体重的儿童出现超重肥胖的风险降低,母亲孕前超重肥胖的儿童出现超重肥胖的风险增加,其OR值及95%CI分别为0.602(0.413~0.755)、1.822(1.370~2.424),均P<0.05;母亲孕期增重过度的儿童出现超重肥胖的风险增加,其OR值及95%CI为1.298(1.009~1.669),P<0.05,但是母亲孕期增重不足并不会降低儿童出现超重肥胖的风险(P>0.05);母亲孕前超重肥胖且孕期增重过度的儿童出现超重肥胖的风险显著增加,母亲孕前低体重且孕期增重不足或孕期增重正常的儿童出现超重肥胖的风险显著降低,其OR值及95%CI分别为1.575(1.031~2.411)、0.556(0.343~0.872)、0.411(0.233~0.719),均P<0.05。结论母亲孕前BMI超重和孕期增重过度均是学龄前儿童发生超重肥胖的影响因素,并且母亲孕前BMI的影响更加严重。     

Mental retardation associated with parental smoking and alcohol consumption before, during, and after pregnancy.

METHODS. In an epidemiologic study, parental alcohol consumption and smoking before, during, and after pregnancy were studied as possible risk factors for mental retardation in offspring. The parents of 306 mentally retarded children (cases) and 322 physically handicapped children (referents) were interviewed about their lifestyle habits from 3 months preconception to 6 months postnatal. RESULTS. Odds ratios with 95% confidence intervals were calculated as risk indicators. For fathers who smoked a pipe or cigars, an odds ratio of 2.4 (95% CI: 1.2-5.1) was observed. Maternal alcohol consumption was increased among the case mothers with risk ratios ranging from 1.7 (95% CI: 1.2-2.3) preconception to 1.4 (95% CI:1.0-2.0) during the fetal period. These risks were more pronounced for the mothers who consumed greater than or equal to 3 drinks/day once or twice a week. CONCLUSIONS. This study suggests that paternal smoking and maternal alcohol consumption are risk factors for mental retardation in offspring.     

CYP1A1 gene polymorphisms in modifying the association between passive smoking and primary dysmenorrhea

PURPOSE: This study investigated whether the association between passive smoking exposure and primary dysmenorrhea is modified by two susceptibility genes, cytochrome P450 1A1 (CYP1A1)MspI and CYP1A1HincII. METHODS: We recruited 1645 female textile workers from 1997 to 2000 in Anqing, China, collecting information about passive smoking and status of primary dysmenorrhea and taking blood samples. We analyzed the association of CYP1A1 gene polymorphisms and passive smoking exposure with primary dysmenorrhea using multiple logistic regression. RESULTS: In the passive smoking group, women who had the C/C6235 genotype (odds ratio [OR] = 1.8; 95% confidence intervals [CI] = 1.0-3.3) in CYP1A1MspI and Ile/Ile462 genotype (OR = 2.9; 95% CI = 1.1-7.7) in CYP1A1HincII had increased risk of dysmenorrhea. When stratified by genotype, the adjusted OR of dysmenorrhea was 1.6 (95% CI = 1.2-2.1) for the passive smoking group with the Ile/Ile462 genotype and 1.5 (95% CI = 1.0-2.1) with the C/C6235 genotype, compared with the nonpassive smoking group. The data further showed that there was a significant combined effect between passive smoking and the CYP1A1MspI C/C6235 and HincII Ile/Ile462 genotypes (OR = 2.4; 95% CI = 1.2-4.9). CONCLUSIONS: CYP1A1MspI and HincII genotypes modified the association between passive smoking and primary dysmenorrhea.     

Passive smoking, cytochrome P450 gene polymorphisms and dysmenorrhea

PURPOSE: This study investigated whether the association between passive smoking exposure and dysmenorrhea is modified by two susceptibility genes, CYP1A1MspI and CYP1A1HincII. METHODS: This report includes 1,645 (1,124 no dysmenorrhea, 521 dysmenorrhea) non-smoking and non-drinking newly wedding female workers at Anqing, China between June 1997 and June 2000. Multiple logistic regression models were used to estimate the associations of passive smoking exposure and genetic susceptibility with dysmenorrhea, adjusting for maternal age, BMI, age of menarche, education, vibration exposure, shift work, noise exposure, pregnancy history, perceived stress and physical laboring stress. RESULTS: In the passive smoking group, women who have C/C6235 genotype (OR = 1.8, 95% CI = 1.0-3.3) in CYP1A1MspI and Ile/Ile462 genotype (OR = 2.9, 95% CI = 1.1-7.7) in CYP1A1HincII was associated with an increased risk of dysmenorrhea. When stratified by women genotype, the adjusted OR of dysmenorrheal was 1.6 (95% CI = 1.2-2.1) for passive smoking group with Ile/Ile462 genotype, and 1.5 (95% CI = 1.0-2.1) with C/C6235 genotype, compared to non-passive smoking group, respectively. The data further showed that there was a significant combined effect between passive smoking and the CYP1A1 Msp1C/C6235 (OR = 1.5, 95% CI = 1.0-2.1), and HincII Ile/Ile462 (OR = 1.6, 95% CI = 1.2-2.1), respectively. CONCLUSION: CYP1A1 MspI and HincII genotypes modified the association between passive smoking and dysmenorrhea.     

Risk factors in term children for visual impairment without a known prenatal or postnatal cause

Risk factors were studied for visual impairment in children without known pre- or postnatal cause, for a decrease of visual acuity. Children born at term 1979-98 and with a visual impairment were identified from the Swedish Register of Visually Impaired Children and data were linked with the Swedish Medical Birth Registry. Maternal characteristics such as maternal age, parity, maternal smoking habits in early pregnancy, maternal education, nationality, and subfertility were studied as well as maternal diagnoses such as pre-eclampsia, prolonged second stage of labour, abruptio placentae, and placenta praevia. Mode of delivery was analysed as well as birthweight, and birthweight in relation to gestational age. Abruptio placentae turned out to be the strongest risk factor (OR = 8.24 [95% CI 5.01, 13.51]). Smoking did not give a statistically significant increased risk. There is an increased risk with breech delivery (OR = 2.01 [95% CI 1.28, 3.17]). Pre-eclampsia was associated with an increased risk (OR = 2.22 [95% CI 1.46, 3.38]). There is also an increase in risk at low birthweight and small-for-gestational-age as well as birthweight > 4 kg and large-for-gestational-age. In this study we found that risk factors particularly worth noticing in term children with a presumed perinatal cause of visual impairment are abruptio placentae, pre-eclampsia, excessively low as well as excessively high birthweight, and breech delivery, a fact worth noticing in current discussion on risks, advantages or excessive exploitation of caesarean section.     

Risk of cancer in children with the diagnosis immaturity at birth

Cancer risk in children born before term has been assessed in a large number of case-control studies but very rarely in cohort studies. We carried out a cohort study of 35 178 children with the diagnosis immaturity at birth in the Hospital Discharge Register during 1977-89. The children were followed for cancer in the Danish Cancer Registry until 1994 and comparisons were made with incidence rates for all children in Denmark. The 64 observed cases of childhood cancer in the cohort corresponded closely to the expected number {standardised incidence ratio (SIR) = 1.03; [95% confidence interval (CI) 0.80, 1.32]}. The only cancer site with an observed number that deviated significantly from the expected number was central nervous system (CNS) tumours (26 cases observed; SIR = 1.57; [95% CI 1.02, 2.30]) in particular medulloblastoma (9 cases observed; SIR = 3.1; [95% CI 1.4, 5.9]). In a nested case-control study of the CNS tumours, we found that more cases than controls had been exposed to diagnostic X-rays, but the result was not significant. Surprisingly, for those born before term, the risk of CNS tumours increased with increasing gestational age in the nested case-control data. Our results are in line with previous evidence that children born before term are not at increased risk for childhood cancer in general. An explanation behind the excess of CNS tumours could not be identified, but the effect of diagnostic X-rays in newborns may deserve further attention.     

Active and passive smoking and risk of breast cancer by age 50 years among German women

Recent studies suggest that both active and passive smokers have an increased risk of breast cancer compared with women who have never been either actively or passively exposed. Data on lifetime active and passive smoking were collected in 1999-2000 from 468 predominantly premenopausal breast cancer patients diagnosed by age 50 years and 1,093 controls who had previously participated in a German case-control study conducted in 1992-1995. Compared with never active/passive smokers, former smokers and current smokers had odds ratios of 1.2 (95% confidence interval (CI): 0.8, 1.7) and 1.5 (95% CI: 1.0, 2.2), respectively, and ever active smokers had an odds ratio of 1.3 (95% CI: 0.9, 1.9). The risk increased with duration of smoking and decreased after cessation of smoking. Among never active smokers, ever passive smoking was associated with an odds ratio of 1.6 (95% CI: 1.1, 2.4). Exposure to environmental tobacco smoke during childhood or before the first pregnancy did not appear to increase breast cancer risk. At greatest risk were women who had a high level of exposure to both passive and active smoking (odds ratio = 1.8, 95% CI: 1.2, 2.7). This study strengthens the hypothesis of a causal relation between active and passive smoke exposures and breast cancer risk.