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BackgroundRecently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.ObjectivesThe authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed.DiscussionWe concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.ConclusionsThe IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public's health.

This study explores the stability and change in maternal life satisfaction and psychological distress following the birth of a child with a congenital anomaly using 5 assessments from the Norwegian Mother and Child Cohort Study collected from Pregnancy Week 17 to 36 months postpartum. Participating mothers were divided into those having infants with (a) Down syndrome (DS; n = 114), (b) cleft lip/palate (CLP; n = 179), and (c) no disability (ND; n = 99,122). Responses on the Satisfaction With Life Scale and a short version of the Hopkins Symptom Checklist were analyzed using structural equation modeling, including latent growth curves. Satisfaction and distress levels were highly diverse in the sample, but fairly stable over time (retest correlations: 0.47-0.68). However, the birth of a child with DS was associated with a rapid decrease in maternal life satisfaction and a corresponding increase in psychological distress observed between pregnancy and 6 months postpartum. The unique effects from DS on changes in satisfaction (Cohen's d = -0.66) and distress (Cohen's d = 0.60) remained stable. Higher distress and lower life satisfaction at later assessments appeared to reflect a persistent burden that was already experienced 6 months after birth. CLP had a temporary impact (Cohen's d = 0.29) on maternal distress at 6 months. However, the overall trajectories did not differ between CLP and ND mothers. In sum, the birth of a child with DS influences maternal psychological distress and life satisfaction throughout the toddler period, whereas a curable condition like CLP has only a minor temporary effect on maternal psychological distress.

This register-based longitudinal study of 392 969 Norwegians examined associations between birth order, gender and educational attainment at age 25 years within families (fixed effects regression) and between families (ordinary OLS regression). Data were retrieved from national registers for births of mothers with single births only and a first birth 1967-1976. Mean education was 12.61 years (SD 2.09). In within-family analysis education decreased with increasing birth order, compared to first born, birth orders two and three were associated with mean decreases of 0.24 years (95% confidence interval [CI] 0.21, 0.26) and 0.32 years (95% CI 0.27, 0.37), respectively. Females had an educational advantage of 0.29 years (95% CI 0.28, 0.31). Birth order effects were moderately stronger for females. With few exceptions, the effects showed similar patterns for subsets of families with different characteristics. Between-family analysis showed that social rather than biologic rank was associated with educational attainment, and that only children and last second children had moderately lower education than their counterparts from larger families. A substantial part of the birth order effect on education was mediated by intellectual performance (General Ability score at conscription). The birth order effect was small, but could have some impact on educational attainment at the population level. (Contains 6 figures and 4 tables.)

The present paper reports the results of a within and between family analysis of the relation between birth order and intelligence. The material comprises more than a quarter of a million test scores for intellectual performance of Norwegian male conscripts recorded during 1984-2004. Conscripts, mostly 18-19 years of age, were born to women for whom almost complete reproductive histories were obtained. Women with single births only 1967-1998 and first birth 1967-1976 were selected for analyses. The grand mean stanine score for intellectual performance standardized for age and calendar year was 5.05 (SD=1.80). The mean standardized score decreased with size of sibship and with higher birth orders in all sibship sizes. These patterns as well as the size of the difference between birth orders 1 and 3 were rather similar between and within families. Among 63,951 adjacent sibling pairs the mean standardized scores were 5.18 (95% confidence interval [CI]: 5.16, 5.19) for the elder and 4.93 (95% CI: 4.91, 4.94) for the younger brother. The difference in mean of standardized scores between adjacent siblings was -0.251 (95% CI: -0.270, -0.231). The difference in mean standardized scores between brothers of adjacent birth orders increased with higher maternal level of education, was highest between brothers of married women, higher with paternal income and decreased with sibship size and longer spacing between births.

Introduction Improved neonatal care has contributed to increased survival among preterm and low birth weight (LBW) infants [1, 2]. However, the risk for chronic conditions requiring a high degree of [...], Children born at term with low birth weight (LBW) are regarded growth restricted and are at particular risk of adverse health outcomes requiring a high degree of parental participation in the day-to-day care. This study examined whether their increased risk of special health care needs compared to other children may influence mothers' opportunities for participation in the labor market at different times after delivery. Data from 32,938 participants in the population-based Norwegian Mother and Child Cohort Study with singleton children born at term in 2004-2006 were linked to national registers in order to investigate the mothers' employment status when their children were 1-3 years in 2007 and 4-6 years in 2010. Children weighing less than two standard deviations below the gender-specific mean were defined as LBW children. Although not significantly different from mothers of children in the normal weight range, mothers of LBW children had the overall highest level of non-employment when the children were 1-3 years. At child age 4-6 years on the other hand, LBW was associated with an increased risk of non-employment (RR 1.39: 95% CI 1.11-1.75) also after adjustment for factors associated with employment in general. In accordance with employment trends in the general population, our findings show that while mothers of normal birth weight children re-enter the labor market as their children grow older, mothers of LBW children born at term participate to a lesser extent in paid employment and remain at levels similar to those of mothers with younger children. Keywords Birth weight * Child care * Employment * Special health care needs * Work participation