Petter Kristensen

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Experimental evidence suggests that inorganic lead and benzo[a]pyrene (BaP) suppress the development of primordial oocytes during fetal life. We examined the single and combined effects of prenatal exposure to BaP and moderate doses of lead. The fertility and ovarian morphology of F1 female NMRI mice in four treatment groups (nine mice per group) were(More)
Negative associations between birth order and intelligence level have been found in numerous studies. The explanation for this relation is not clear, and several hypotheses have been suggested. One family of hypotheses suggests that the relation is due to more-favorable family interaction and stimulation of low-birth-order children, whereas others claim(More)
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)(More)
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(More)
BACKGROUND Adverse health effects caused by pesticide exposure have been reported in occupied Palestinian territory and the world at large. The objective of this paper is to compare patterns of pesticide use in Beit-U'mmar village, West Bank, between 1998 and 2006. METHODS We studied two populations in Beit-U'mmar village, comprised of: 1) 61 male farmers(More)
Measurement errors in two variables are dependent when the degree of error in one of them correlates with the degree of error in the other. When dependent error affects measured exposure and measured outcome, the estimated association between the two is likely to be falsely inflated. Such information bias is probably not uncommon in cross-sectional studies(More)
BACKGROUND In 2001, the Norwegian authorities and major labour market partners signed an agreement regarding 'inclusive working life' (IW), whereby companies that participate are committed to reducing sickness absence. Our main aim was to determine the effect of the IW program and work characteristics by gender on long-term (>8 weeks) sickness absence(More)
BACKGROUND Recently, 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(More)
BACKGROUND Social inequalities in health can to a substantial degree be explained by social causation. However, indirect selection by early life factors has been suggested. The main aim of this study was to estimate how much adult social gradients in selected psychiatric outcomes depended on parental and individual characteristics in early life. METHODS(More)
BACKGROUND Road traffic injury is a major cause of death among youths. AIMS To estimate mortality differences in family socioeconomic position (SEP) and municipal disadvantage level. METHODS Data on all Norwegians born in 1967-76, gathered from national registries, were linked by a unique national identification number. The 611 654 participants were(More)