Perinatal risk factors for infantile autism

BACKGROUND: Etiologic hypotheses in infantile autism suggest a strong genetic component, as well as possible environmental risks linked to early fetal development. We evaluated the association of maternal, pregnancy, delivery, and infant characteristics and risk of infantile autism. METHODS: We conducted a case-control study nested within a population-based cohort (all Swedish children born in 1974-1993). We used prospectively recorded data from the Swedish Birth Register, which were individually linked to the Swedish Inpatient Register. Cases were 408 children (321 boys and 87 girls) discharged with a main diagnosis of infantile autism from any hospital in Sweden before 10 years of age in the period 1987-1994, plus 2,040 matched controls. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: The risk of autism was associated with daily smoking in early pregnancy (OR = 1.4; CI = 1.1-1.8), maternal birth outside Europe and North America (OR = 3.0; CI = 1.7-5.2), cesarean delivery (OR = 1.6; CI = 1.1-2.3), being small for gestational age (SGA; OR = 2.1; CI = 1.1-3.9), a 5-minute Apgar score below 7 (OR = 3.2, CI = 1.2-8.2), and congenital malformations (OR = 1.8, CI = 1.1-3.1). No association was found between autism and head circumference, maternal diabetes, being a twin, or season of birth. CONCLUSIONS: Our findings suggest that intrauterine and neonatal factors related to deviant intrauterine growth or fetal distress are important in the pathogenesis of autism.     

Risk factors for anorexia nervosa: a national cohort study

OBJECTIVE: To identify possible risk factors for anorexia nervosa through national registers. METHOD: The study includes the entire Swedish population of 989,871 individuals born between 1973 and 1982. Patients with anorexia nervosa were identified through the Swedish Hospital Discharge Register from November 1990 to December 1999. Information about sociodemographic, perinatal, and psychosocial variables was obtained from different national registers. Attributable risk (AR) was calculated for potential risk factors. RESULTS: Females had the highest AR for hospital admission because of anorexia nervosa (89.2%). Another important risk factor was having parents born in northern, central, or eastern Europe (AR: 49.3%). Psychosocial risk factors also were associated with an increased risk for anorexia nervosa (AR: 7.6%), whereas perinatal complications had an AR of only 3.6%. DISCUSSION: The most important risk factors were related to the sociocultural context of the individual, thus supporting hypotheses of a sociocultural etiology of anorexia nervosa.     

Perinatal characteristics and risk of polio among Swedish twins

Perng W, Cnattingius S, Iliadou A, Villamor E. Perinatal characteristics and risk of polio among Swedish twins. Paediatric and Perinatal Epidemiology 2012; 26: 218–225. Prenatal exposure to adverse environmental conditions is related to increased adult mortality in regions where infections are highly prevalent, yet there is little evidence of the impact of perinatal conditions on the risk of severe infections throughout life. Using prospectively collected data from 21 604 like‐sexed Swedish twins of known zygosity born in 1926–1958, we examined the risk of polio in relation to perinatal characteristics using cohort and nested co‐twin case–control analyses. Polio incidence was determined through an interview in 1998, and linkage with the Swedish national inpatient and death registries. There were 133 cases of polio. In the cohort analysis, birth length, birthweight and head circumference were positively associated with polio risk. After adjustment for sex, birth year, gestational age at birth and within‐twin pair correlations, twins of shortest length (<44 cm) had a 67% ([95% CI: 6%, 88%]; P = 0.04) lower risk of polio compared with the reference group (47–49 cm). After additional adjustment for birth length, every 100‐g increase in birthweight was related to a 34% increased risk of polio ([95% CI: ?1%, 82%]; P = 0.06), and every 10‐mm increase in head circumference was related to a 17% greater risk of polio ([95% CI: 5%, 31%]; P = 0.004). In co‐twin control analyses among 226 disease‐discordant twins, birth length, birthweight and head circumference were 0.3 cm (P = 0.19), 84 g (P = 0.07) and 3 mm (P = 0.08) higher in cases than controls, respectively. Similar associations were observed among monozygotic (n = 84) and dizygotic (n = 142) twins. These findings suggest that early intrauterine growth restriction may be inversely related to the incidence of polio.     

Household pesticides and the risk of Wilms tumor

BACKGROUND: Previous epidemiologic studies have suggested that exposure to pesticides in utero and during early childhood may increase the risk for development of childhood cancer, including Wilms tumor, a childhood kidney tumor. OBJECTIVES: In this analysis we evaluated the role of residential pesticide exposure in relation to the risk of Wilms tumor in children using data from a North American case-control study. METHODS: The National Wilms Tumor Study Group (NWTSG) collected information on exposure to residential pesticides from the month before pregnancy through the diagnosis reference date using detailed phone interviews from 523 case mothers and 517 controls frequency matched on child's age and geographic region and identified by list-assisted random digit dialing. Pesticides were grouped according to type of pesticide and where they were used. RESULTS: A slightly increased risk of Wilms tumor was found among children of mothers who reported insecticide use [odds ratio (OR) = 1.4, 95% confidence interval (CI), 1.0-1.8; adjusted for education, income, and the matching variables]. Results from all other categories of pesticides were generally close to the null. CONCLUSIONS: This study is the largest case-control study of Wilms tumor to date. We were unable to confirm earlier reports of an increased risk for Wilms tumor among those exposed to residential pesticides during pregnancy through early childhood.     

Socio-economic risk factors for injuries in Swedish children and adolescents: A national study over 15 years

Abstract

Few studies have assessed if Sweden's injury prevention work has been equally effective for children of different socio-economic backgrounds. The goal of this paper is to review the country's injury rates for children over time, stratified by socio-economic status (SES), to see if the effects are similar across SES levels. This study employs a retrospective case-control study design, using data from the hospitalisation records of 51,225 children, which were linked to family socio-economic data. Children and adolescents in families receiving social welfare benefits, and those living with single parents and mothers with less education had higher risks of injuries leading to hospitalisation. The population-based safety work over the past decades seems to have had only minor effects on reducing the impact of socio-economic based difference in injury risks to younger Swedes.     

Perinatal risk factors for inflammatory bowel disease: a case-control study

To examine perinatal risk factors for Crohn's disease and ulcerative colitis, the authors analyzed birth records for 257 known case participants delivered from 1924 through 1957 at the University Hospital in Uppsala County, Sweden, and compared them with records for 514 controls delivered at the hospital. The two groups were matched by date of birth, sex, and either maternal age or parity. Eleven study variables were abstracted from standard forms that recorded health events during the pregnancy and the delivery hospitalization. Participants were more likely than controls to have a recorded health event (odds ratio (OR) = 4.4; 95% confidence interval (CI) 3.0-6.4). In a multivariate model, this increased risk was evident for infectious (OR = 3.8; 95% CI 2.6-5.8) and noninfectious (OR = 3.5; 95% CI 2.0-6.3) events. Perinatal health events may have contributed to 40% of the inflammatory bowel disease cases in our study. Infants from families with low socioeconomic status had greater risk of inflammatory bowel disease than did infants from families with high socioeconomic status (OR = 3.0, 95% CI 1.5-6.1). Perinatal health events and low socioeconomic status independently increased the risk of inflammatory bowel disease.     

Perinatal medication as a potential risk factor for adult drug abuse in a North American cohort

The aim of this study was to explore perinatal exposures to medications as risk factors for adult drug abuse. We compared 69 drug abusing subjects and their 33 non-abusing siblings with regard to history of labor pain analgesia during birth and other obstetric variables. Three or more doses of opiates or barbiturates at birth yielded an OR of 4.7 (95% CI = 1.0-44.1) for becoming a drug abuser after multiple perinatal drug exposure.     

Perinatal factors and risk of neuroblastoma

Neuroblastoma is a malignancy commonly diagnosed during infancy or early childhood, raising speculation about the role of perinatal factors and risk of disease. Using a case-control design, cases included 155 infants and children aged 0-5 years with histologically confirmed neuroblastoma diagnosed and reported to the New York State Cancer Registry between 1976 and 1987. Controls were randomly selected from the State's Livebirth Registry and were frequency matched to cases on year of birth (n = 310). Medical records of cases were used to verify histology and stage of disease. Data on perinatal factors were ascertained from birth certificates and standardised telephone interviews with mothers. Unconditional logistic regression was used to estimate (un)adjusted odds ratios (OR) and 95% confidence intervals (CI). Both preterm (< 37 weeks) and post-term (> 42 weeks) birth were associated with a reduction in risk (OR = 0.4 [CI = 0.1, 0.9] and OR = 0.3 [CI = 0.1, 0.7] respectively) after controlling for confounders in unconditional logistic regression analysis. Elevated risk factors included: smoking during pregnancy (OR = 1.6; CI = 0.9, 2.8), contracted pelvis (OR = 2.3; CI = 0.6, 9.8), birth injury (OR = 2.9; CI = 0.3, 24.9) and 1-min Apgar Score < or =3 (OR = 6.0; CI = 0.9, 38.6); all confidence intervals included one. These data suggest that extremes in gestation may be associated with a reduced risk, although aetiological mechanisms remain unknown.     

Fetal exposure, heredity and risk indicators for cardiovascular disease in a Swedish welfare cohort

BACKGROUND: The overall aim was to test whether low birthweight (LBW) in newborns is associated with the risk indicators for cardiovascular disease in early middle age, even in a welfare society. Further, a possible interaction of LBW and heredity for myocardial infarction or stroke was investigated. METHODS: Overall, subjects were identified as newborns in a local birth register, and as adult participants, in the V?sterbotten Intervention Program (n = 7876). Outcome measures such as systolic (SBP) and diastolic blood pressures (DBP), body mass index (BMI), cholesterol, triglycerides and anthropometrics were investigated (at age 29-41 years) in relation to LBW. RESULTS: Low birthweight was associated with increased SBP and DBP. Triglycerides were elevated among women with LBW and total cholesterol was elevated in men with LBW. Heredity for myocardial infarction or stroke interacted with LBW, and indicated a synergistic effect on the level of SBP. The BMI did not differ between LBW and normal birthweight subjects. CONCLUSIONS: Our interpretation is that the 'fetal origins' hypothesis' is valid for middle-age subjects who grow up in a welfare society. The population attributable proportions that result from different exposures to LBW were relatively small overall; from a public health perspective, heredity was more important than LBW for elevated SBP.     

Prenatal and postnatal risk factors for infantile pneumonia in a representative birth cohort

Pneumonia is an important cause of mortality and morbidity in infants. However, information of risk factors for pneumonia in children aged <6 months is limited. This study aimed to evaluate the risk factors and their contribution to infantile pneumonia in a large population-based survey. Of 24,200 randomly sampled main caregivers invited, 21,248 (87.8%) participated in this study. A structured questionnaire was used to interview the main caregivers. Information regarding whether hospitalization was required, family environment, and medical history were obtained. The prevalence of pneumonia was 0.62% in our study cohort. Multivariate logistic regression analysis showed that preterm birth, congenital cardiopulmonary disease, antibiotic use during pregnancy, maternal overweight, daily prenatal exposure to environmental tobacco smoke, maternal smoking during pregnancy, and visible mould on walls at home are risk factors associated with infantile pneumonia. Further study is warranted to investigate the causality and mechanisms of these novel factors.     

Lifestyle and anthropometric risk factors for prostate cancer in a cohort of Iowa men

PURPOSE: Several lines of evidence suggest that prostate cancer has a hormonal etiology. We evaluated factors known to modulate the endocrine system, including alcohol and tobacco use, physical activity, and obesity as risk factors for prostate cancer. METHODS: Cancer-free controls who participated in a population-based case-control study from 1986-1989 (81% response rate) were followed through 1995 for cancer incidence by linkage to the Iowa Cancer Registry; 101 incident prostate cancers were identified. RESULTS: Compared with non-users of alcohol, men who consumed <22 grams alcohol per week (relative risk [RR] = 1.1; 95% Confidence Interval [CI] 0.6-2.1), 22-96 grams alcohol per week (RR = 2.6; 95% CI 1.4-4. 6) and >96 grams alcohol per week (RR = 3.1; 95% CI 1.5-6.3) were at increased risk of prostate cancer after adjustment for age, family history of prostate cancer, body mass index, total energy, and intake of carbohydrate, linoleic acid, lycopene, retinol, and red meat (p for trend < 0.0001). The respective RRs were similar when assessing type of alcohol consumed (beer, wine or liquor) or when well-differentiated, localized tumors were excluded. Body mass index was only weakly and positively associated with prostate cancer after adjustment for age, but this association strengthened after multivariate adjustment and exclusion of well-differentiated, localized tumors. For the latter tumors, men with a BMI of 24.1-26.6 kg/m(2) and >26.6 kg/m(2) were at elevated risk compared to men with a BMI <24.1 kg/m(2). Tobacco use (cigarettes, cigar/pipe, chewing tobacco and snuff use), height, weight, and both leisure and occupational physical activity were not associated with risk of prostate cancer in this cohort. CONCLUSIONS: These data suggest that in white men obesity is a risk factor for more clinically significant prostate cancer and confirm limited previous reports showing that alcohol consumption is positively associated with prostate cancer and that this risk is not limited to any specific type of alcohol.     

Socioeconomic and occupational risk factors for pancreatic cancer: a cohort study in Sweden

OBJECTIVE: The objective of this study was to examine the associations between socioeconomic/occupational factors and pancreatic cancer. METHODS: The Swedish Family-Cancer Database was used to calculate standardized incidence ratios for different social classes and occupational groups. Lung cancer risks were also determined. The reference group was all the economically active population. RESULTS: Farmers were at a decreased risk of pancreatic cancer. A slightly increased risk of pancreatic cancer, independent of lung cancer, was observed for male professionals and administrators and managers. For women, increased risks were observed for cooks and stewards, and glass, ceramic, and tile workers. CONCLUSIONS: The results show that socioeconomic/occupational factors play a small role in the etiology of pancreatic cancer. In addition to smoking, physical inactivity and obesity may contribute to the observed differences.     

Complicated bereavement: a national survey of potential risk factors

We developed a Bereavement Risk Questionnaire to rate 19 possible factors for assessing complicated bereavement. A four-point scale was used (0 = no risk, 3 = significant risk). The questionnaire was mailed nationwide in the United States to 508 hospice bereavement coordinators, and 262 responded. Most rated the following as significant risks: perceived lack of caregiver social support (70 percent), caregiver history of drug/alcohol abuse (68 percent), caregiver poor coping skills (68 percent), caregiver history of mental illness (67 percent), and patient is a child (63 percent). Overall, 61 percent chose perceived lack of social support, and 47 percent chose poor coping skills, as one of the top three risk factors. There was no relationship between professional discipline and responses. We found a consensus among bereavement professionals regarding important indicators in assessing bereavement risk. We conclude that it is possible to assess bereavement risk in caregivers of seriously ill patients, prior to the death of the patient. This would allow palliative care teams to allocate resources and services to those at the greatest risk for complicated bereavement.     

Mortality and risk factors for stroke and its subtypes in a cohort study in Japan

OBJECTIVE: To estimate stroke mortality and evaluate risk factors for total stroke deaths and its two principal subtypes in a cohort study in Japan. METHODS: A total of 9651 subjects aged 40 or over and free of stroke were analyzed in a cohort study conducted in Fukuoka Prefecture, Japan. The follow-up period was from 1986 to 2003. Mortality rate per 100,000 person-years of stroke was estimated. The Cox proportional hazards model was used to estimate the hazard ratios and 95% confidence interval. RESULTS: A total of 226 stroke deaths were recorded during 132,972 years of follow-up. Among these, 47 were intracerebral hemorrhage and 109 were cerebral infarction. Stroke mortality rates were 209.4 per 100,000 person-years in males, and 140.5 in females. The results showed that advanced age, male gender, low body mass index (BMI), history of diabetes, hypertension, and transfusion were associated with an increased risk of mortality from total stroke. CONCLUSION: We confirmed that advanced age, male gender, low BMI, history of diabetes, history of hypertension and history of transfusion were associated with an increased risk of total stroke mortality. In addition, the magnitude of these associations differed between the two principal stroke subtypes.     

Major dietary patterns and risk of renal cell carcinoma in a prospective cohort of Swedish women

Links between specific foods and the risk of renal cell carcinoma (RCC) are not well established. Dietary patterns may be a better predictor of RCC risk. Our aim was to identify and examine major dietary patterns and their relation to the risk of RCC in a large prospective cohort study of Swedish women. Complete dietary information was available from a FFQ from 46,572 women aged 40-76 y at baseline. We conducted factor analysis to identify dietary patterns. Cox proportional hazard models were used to estimate rate ratios (RRs) and 95% CIs. During a mean of 14.3 y of follow-up, we identified 93 cases of RCC. We observed 3 major dietary patterns in the cohort: Healthy (vegetables, tomato, fish, fruits, poultry, whole grains), Western (sweets, processed meat, refined grains, margarine/butter, high-fat dairy products, fried potato, soft drinks, meat) and Drinker (wine, hard liquor, beer, snacks) pattern. Higher Healthy pattern scores were not significantly associated with decreased risk of RCC (highest vs. lowest tertile RR = 0.81; 95% CI 0.45-1.48 and RR = 0.54; 95% CI 0.27-1.10 among women < or = 65 y). There was a suggestion of an inverse association between the Drinker pattern and RCC risk (RR comparing the 2nd and 3rd with the first tertile, 0.56; 95% CI, 0.34-0.95; and 0.72; 95% CI, 0.42-1.22, respectively, P = 0.08 by Wald test); the association was clearer among women < or = 65 y (P = 0.02 by Wald test). Our data suggest an inverse association between Drinker pattern and the risk of RCC.     

Genetic susceptibility to burnout in a Swedish twin cohort

Most previous studies of burnout have focused on work environmental stressors, while familial factors so far mainly have been overlooked. The aim of the study was to estimate the relative importance of genetic influences on burnout (measured with Pines Burnout Measure) in a sample of monozygotic (MZ) and dizygotic (DZ) Swedish twins. The study sample consisted of 20,286 individuals, born 1959–1986 from the Swedish twin registry who participated in the cross-sectional study of twin adults: genes and environment. Probandwise concordance rates (the risk for one twin to be affected given that his/her twin partner is affected by burnout) and within pair correlations were calculated for MZ and DZ same—and opposite sexed twin pairs. Heritability coefficients i.e. the proportion of the total variance attributable to genetic factors were calculated using standard biometrical model fitting procedures. The results showed that genetic factors explained 33% of the individual differences in burnout symptoms in women and men. Environmental factors explained a substantial part of the variation as well and are thus important to address in rehabilitation and prevention efforts to combat burnout.