Adolescents bullying and young adults body mass index and obesity: a longitudinal study.

OBJECTIVE: To examine whether adolescent males and females who were victims of bullying were at greater risk of a higher body mass index (BMI) and obesity by young adulthood. DESIGN: Secondary analysis of data from a community-based cohort study. SUBJECTS: A sub-sample of 1694 offspring (50% males) who were participants in the Mater-University of Queensland Study of Pregnancy (MUSP), Brisbane, and who provided bullying information at 14 years and physical assessment at 21 years. MAIN OUTCOME MEASURES: BMI and its categories as normal, overweight or obese at 21 years. RESULTS: One in two adolescent males and one in three adolescent females reported that they had been bullied at school by others. We found that adolescent males and females who were bullied were at a significantly greater risk of a higher BMI and obesity by young adulthood. Fourteen-year-old males who were occasionally/often bullied at school had 0.64 (95% confidence interval (CI): 0.02, 1.27) kg m(2) greater mean BMI by 21 years compared with males who were never bullied by 14 years. This mean difference in BMI was 1.52, (95% CI: 0.75, 2.29) kg m(2) for females. Similarly, the odds of being obese were 2.54 (95% CI: 1.58, 4.09) times at 21 years for those males who were bullied occasionally/often compared with adolescent males who were never bullied. For females, this was 2.18 (95% CI: 1.40, 3.39). Overweight adolescents who experienced bullying had the greatest increase in BMI by young adulthood. Adjusting for potential confounding or mediating factors, the associations remain strong for males but are attenuated for females. CONCLUSIONS: The findings of this study suggest that both male and female adolescents who were bullied often/sometimes by their peer group at 14 years were at greater risk of higher BMI and obesity by young adulthood.

Longitudinal correlates of the persistence of irregular eating from age 5 to 14 years.

AIM: To report the stability of parent-perceived child irregular eating from 6 months to 14 years of age and to investigate a predictive model inclusive of child and parent factors. METHODS: Of the 7223 singleton children in a birth cohort, 5122 children were re-interviewed at 5 years and 4554 for the 14-year analysis. Information was obtained from structured interviews including questions answered by parents of the child at birth, 6 months, 5 years and 14 years; and by teenagers at age 14 years and from physical measures of the child. The mother's perception that the child was an irregular eater at age 14 years was the major outcome variable of interest. RESULTS: Approximately 40% of irregular eaters at age 5 will still be irregular eaters at age 14 years. This was not related to maternal education or socio-economic class. Significant at multivariate analysis were infant feeding problems and the children's ability to regulate their sleep and mood. Significant maternal factors were greater age, not feeling positive about the baby and persistent maternal anxiety during the child's early years. CONCLUSION: Irregular eating behaviour displays considerable continuity from childhood to mid-adolescence. Independent contributions to this behavioural phenotype include child biological and psychological factors and maternal anxiety during the child's early years.

Maternal smoking during and after pregnancy and lung function in early adulthood: a prospective study.

BACKGROUND AND AIMS: There is a paucity of evidence about whether exposure to antenatal smoking impacts on offspring's lung function in early adulthood. This study aimed to examine whether (1) in utero exposure to maternal smoking is related to poorer respiratory functioning in early adulthood; (2) the impact of prenatal smoking is independent of postnatal maternal smoking; and (3) the link between prenatal smoking and a young adult's lung function is explained by the child's birth weight, smoking or history of asthma. METHODS: Data were from a 21-year follow-up of mothers and their children recruited into the Mater-University of Queensland Study of Pregnancy, a longitudinal prebirth cohort. The study is based on 2409 young adults (1185 males and 1224 females) who had prospective data available on respiratory function at 21 years and maternal smoking during and after pregnancy. A Spirobank G spirometer system was used to measure forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)) and forced expiratory flow between 25% and 75% of FVC (FEF(25-75)). RESULTS: In utero exposure to maternal smoking was associated with a reduction in FEV(1) and FEF(25-75) in males (regression coefficient, -0.16; 95% CI, -0.30 to -0.02), after accounting for maternal smoking after pregnancy. At least part of the effect of in utero smoking on young adults' lung function was explained by the child's birth weight and subsequent asthma. CONCLUSIONS: Adverse effects of antenatal smoking on development of airway growth may persist into early adulthood. Gender differences noted in this longitudinal cohort need to be explored further.

Predictors of maternal misclassifications of their offspring's weight status: a longitudinal study.

BACKGROUND: Very little is known about the factors influencing parental misclassifications of a child's weight status. The aim of this study is to examine the predictors of maternal misclassifications of their adolescent offspring's weight status. METHODS: A mother-child linked analysis was carried out using 14-year follow-up data from a population-based prospective birth cohort of 2650 children (52% males) who were participants in the Mater-University Study of Pregnancy in Brisbane (Australia) in 1981. Offspring's observed height and weight and maternal perception of offspring weight were reported when they were 14 years old and predictors were prospectively recorded either at first clinical visit of mothers or at 5 or 14 years follow-up. Maternal misclassifications were defined combining observed body mass index (BMI) categories and maternal perceptions of their offspring's weight status. RESULTS: We found that maternal misclassification of child's weight status was common and included misclassifications both to higher and lower weight categories. Forty percent of mothers of overweight children misclassified their child as normal or underweight, more so in males than females. Fifteen percent of mothers of normal weight children misclassified their child as underweight, again more so in males than females. The main independent predictors of maternal misclassifications of child weight status were gender, child dissatisfaction with appearance, shape, size and weight, dieting to lose weight, general health status, maternal BMI and family meals. Gender, child dissatisfaction, dieting and maternal overweight were especially associated with misclassifications of overweight children. CONCLUSIONS: This study identified a number of maternal, child and family factors associated with maternal misclassifications of child weight status. Although relevant for clinical practice, further study is needed, however, to evaluate the benefits and harms of promoting increasing parental and child awareness of the child's weight status at a population level.

Selective increases in regional brain glucocorticoid: a novel effect of chronic alcohol.

The hypothalamo-pituitary-adrenal axis shows functional changes in alcoholics, with raised glucocorticoid release during alcohol intake and during the initial phase of alcohol withdrawal. Raised glucocorticoid concentrations are known to cause neuronal damage after withdrawal from chronic alcohol consumption and in other conditions. The hypothesis for these studies was that chronic alcohol treatment would have differential effects on corticosterone concentrations in plasma and in brain regions. Effects of chronic alcohol and withdrawal on regional brain corticosterone concentrations were examined using a range of standard chronic alcohol treatments in two strains of mice and in rats. Corticosterone was measured by radioimmunoassay and the identity of the corticosterone extracted from brain was verified by high performance liquid chromatography and mass spectrometry. Withdrawal from long term (3 weeks to 8 months) alcohol consumption induced prolonged increases in glucocorticoid concentrations in specific regions of rodent brain, while plasma concentrations remained unchanged. This effect was seen after alcohol administration via drinking fluid or by liquid diet, in both mice and rats and in both genders. Shorter alcohol treatments did not show the selective effect on brain glucocorticoid levels. During the alcohol consumption the regional brain corticosterone concentrations paralleled the plasma concentrations. Type II glucocorticoid receptor availability in prefrontal cortex was decreased after withdrawal from chronic alcohol consumption and nuclear localization of glucocorticoid receptors was increased, a pattern that would be predicted from enhanced glucocorticoid type II receptor activation. This novel observation of prolonged selective increases in brain glucocorticoid activity could explain important consequences of long term alcohol consumption, including memory loss, dependence and lack of hypothalamo-pituitary responsiveness. Local changes in brain glucocorticoid levels may also need to be considered in the genesis of other mental disorders and could form a potential new therapeutic target.

Alterations in mesolimbic dopamine function during the abstinence period following chronic ethanol consumption.

Previous work demonstrated that the locomotor stimulant actions of amphetamine, cocaine and nicotine were increased when these drugs were given during the abstinence phase after chronic ethanol consumption. These changes were seen at 6 days and at 2 months after cessation of alcohol. The present study examined neuronal alterations which might be related to these changes in behaviour. Markedly reduced spontaneous firing rates of dopaminergic cells in the ventral tegmental area (VTA) in midbrain slices were seen 6 days into the abstinence period after cessation of chronic ethanol consumption, but by 2 months the firing rates had returned to control values. Increased affinity of striatal receptors for the D1-like receptor ligand 3H-SCH23390, but no change in the receptor density, was found both at the 6 day and the 2 month intervals. The binding properties of striatal D2-like receptors, of D1-like and D2-like receptors in the frontal cerebral cortex, and the release of tritiated dopamine from slices of striatum or frontal cerebral cortex, were unchanged at 6 days and 2 months. It is suggested that the decreased neuronal firing leads to a persistent increase in sensitivity of D1-like receptors and that these changes could explain the increased effects of the other drugs of abuse.

Effects of intraperitoneal injections of saline on the alcohol and sucrose consumption of C57/BL10 mice.

RATIONALE: To determine the effects of multiple saline injections on alcohol drinking by male and female C57/BL10 mice with low preference for alcohol. OBJECTIVE: An investigation of the effects of multiple saline injections on alcohol consumption, with a comparison of corresponding effects on sucrose consumption. METHODS: The effects of a range of injection schedules on preference for 8% alcohol, or 1% sucrose, compared with tap water, were measured in two-bottle choice tests. RESULTS: The multiple saline injection schedule significantly increased the alcohol preference, even when no alcohol was available during the injection period. The actual administration of fluid was not necessary for the increase in alcohol preference, since sham injections without fluid administration also increased alcohol preference. A single injection of saline did not alter the alcohol preference 3 weeks later. Daily saline injections for 3 weeks did not alter the consumption of the dilute sucrose solution. In the population of mice used, the preference for sucrose over water was found to follow a biphasic distribution, similar to that reported earlier in these mice for alcohol preference, but there was no correlation between alcohol preference and sucrose preference. CONCLUSIONS: The results suggest that lasting changes in the areas of the brain that specifically control alcohol intake are produced by repetition of a routine laboratory procedure.

Low alcohol preference among the "high alcohol preference" C57 strain of mice; preference increased by saline injections.

RATIONALE AND OBJECTIVE: This study investigated individual alcohol preference among the "high alcohol preferring" strain of C57BL10 (line ScSn) mice. METHODS: Alcohol preference was assessed in free choice two-bottle preference tests, using 8% ethanol and tap water, under various conditions. RESULTS: Between 15 and 40% of the mice, bred in house, showed a low preference for alcohol with ethanol/water ratios of 0.4 or less. There was a biphasic distribution of preference, and no relationship between alcohol preference and gender. Mice of the C57BL/6 strain from an outside breeder also contained animals with low preference for alcohol. Selective breeding from "in house" stock did not demonstrate evidence of a simple genetic link. Ethanol preference showed no correlation with locomotor activity or the effects of alcohol on such activity. Daily intraperitoneal injections of saline increased the preference of low preference mice, an effect prevented by the CCK(B) antagonist, CAM1028. The preference of "low preference" mice was significantly increased when the effects of saline injections were compared with those of handling alone. Diazepam, at 1 mg/kg, did not affect the low preference, compared with Tween vehicle. This demonstration of C57 strain mice with low preference for alcohol may provide a valuable model for the effects of stress on alcohol consumption.

The prevalence and origins of left hand preference in high risk infants, and its implications for intellectual, motor and behavioural performance at four and six years.

This study investigates the origins of hand preference at 4 years in a cohort of 115 high risk and premature infants; the relationship between patterns of hand preference and intellectual, motor, temperament and behavioural status at 4 and 6 years; and evidence for brain injury in mediating the relationship between hand preference and development disorder. Increased left hand preference was independently associated with extreme prematurity, high neonatal risk, increased numbers of minor physical anomalies, lowered intellectual and motor abilities, and more difficult temperament. These findings supported the presence of intrauterine and neonatal pathological mechanisms leading to left hand preference in a small number of children. Neither poor function of the non dominant hand nor absence of a family history of left handedness could further define this pathological subgroup. Support for pathological mechanisms producing left handedness was found predominatly in the infants of high birth weight, whereas prevalence of left handedness was increased mainly among the extremely low birth weight infants. In this latter group the prevalence of left handedness was also increased among children of normal intelligence, suggesting that mechanisms other than brain damage lead to left hand preference in very premature infants.

Handedness in extremely low birth weight infants: aetiology and relationship to intellectual abilities, motor performance and behaviour at four and six years.

Hand preference was measured in a total group of 71 ELBW children to determine patterns of hand preference at 4 and 6 years, possible aetiological factors leading to handedness, and whether left or non right hand preference were markers for intellectual, motor, temperament or behavioural differences. At both 4 and 6 years the prevalence of left handedness was increased, though this prevalence changed over the period of the study. Results supported brain injury as one mechanism leading to increased left hand preference, though this process did not adequately explain this increase. Possible reasons for this and the apparent change in prevalence with time are examined. Mixed handedness at 4 years was associated with lower intellectual abilities though otherwise children were similar in motor skills, temperament and behaviour independent of hand preference category.

Neurodevelopmental outcome of preterm infants with bronchopulmonary dysplasia.

The neurodevelopmental outcome of 78 infants with bronchopulmonary dysplasia (BPD) was compared with that of 78 control infants matched for birthweight. To determine the effect of the severity of BPD, 62 infants requiring oxygen at 36 weeks' postmenstrual age (sBPD) were compared with their matched controls. Infants were followed up to 2 years of age, corrected for prematurity, and were classified for neurological impairment, developmental delay, and neurodevelopmental disability. Seventy six (98%) BPD infants and 71 (91%) controls had follow up data available to two years. Neurological impairment, developmental delay, and neurodevelopmental disability occurred more frequently in infants with BPD than in controls but this was not significant. For infants with sBPD, the increased incidence of neurological impairment and definite developmental delay was not significant when compared with the controls, though neurodevelopmental disability occurred more frequently (odds ratio (OR) 3.6: 95% confidence intervals (CI) 1.1-11.8). Predictors of disability in infants with sBPD included periventricular haemorrhage (OR 19.4: 95% CI 4.3-86.6), ventricular dilatation (OR 12.8: 95% CI 2.9-57.3), and sepsis (OR 5.0: 95% CI 1.3-19.4). Adjusting for the presence of these factors, the association between BPD and disability was no longer apparent (OR 0.9: 95% CI 0.2-3.6). The findings suggest that BPD is not independently associated with adverse neurodevelopmental outcome.

Maternal hypertension and neurodevelopmental outcome in very preterm infants.

AIM: To determine the outcome of preterm infants born to mothers with hypertension during pregnancy, and preterm controls. METHODS: 107 infants of 24-32 weeks gestation, born to hypertensive mothers, and 107 controls matched for gestational age, sex, and multiple pregnancy, born to normotensive mothers, were prospectively enrolled over 2 years. Information on maternal complications and medication was obtained and neonatal mortality and morbidities recorded. Survivors were followed up to at least 2 years, corrected for prematurity. RESULTS: One third of the hypertensive mothers were treated with antihypertensive drugs, while 18% received convulsion prophylaxis with phenytoin. Magnesium sulphate was not prescribed. Both groups had a mean gestational age of 29.9 weeks, with the study infants having a significantly lower birthweight than the controls. Four study and three control infants died in the neonatal period. Cerebral palsy was not diagnosed in any infant of a hypertensive mother compared with five of the controls. The mean general quotient for the two groups was very similar and no difference in the incidence of minor neuromotor developmental problems was shown. CONCLUSIONS: Maternal hypertension seems to protect against cerebral palsy in preterm infants without increasing the risk of cognitive impairment. This was independent of the use of maternally administered magnesium sulphate.

Low alcohol preference among the "high alcohol preference" C57/BL10 mice; factors affecting such preference.

The effects of age, ethanol concentration and minor stress on the variation in alcohol preference of C57 strain mice were determined. In two bottle choice tests, an older population of mice contained slightly more low-preference mice than a younger population. A wide range of ethanol preference was consistently seen in young mice for 8% and 6% ethanol, but the previously reported biphasic pattern of distribution was revealed only with 8% ethanol. Very few animals showed high preference for concentrations of 10% or 12% ethanol. Moving low alcohol preference mice to a new location (but not repeated cage changing or ultrasonic noise) significantly increased the alcohol preference. Exploratory locomotor activity did not correlate with the subsequent alcohol consumption. Blood and brain alcohol concentrations showed that the differences in alcohol preference were not due to differences in metabolism of ethanol. The C57 strain mice with low preference for alcohol provides a valuable model for the study of the effects of minor stress on alcohol consumption.

Gender differences in cognitive abilities at 2 years in ELBW infants. Extremely low birth weight.

Gender differences in cognitive abilities exist for children born at term. For very preterm infants uncertainty exists regarding the presence and extent of such differences and their relationship to perinatal brain injury and neurological impairment. This study examined gender differences in cognitive abilities in a cohort of 336 extremely low birth weight (ELBW) infants at 2 years corrected age. Infants were classified as at low or high perinatal risk at birth according to four perinatal risk factors. A subgroup of 33 neurologically impaired infants was identified. Outcome at 2 years was measured by the overall General Quotient (GQ) on the Griffiths scale and its five subscale scores. Female ELBW children were superior to male ELBW children by 4.1 GQ points (95% CI 1.0, 7.1). If the impaired subgroup was excluded, the difference in GQ was 3.2 points (95% CI 0.4, 5.6), and this difference was predominantly due to female infants being superior in the hearing and speech subscale (6.0 points, 95% CI 2.6, 9.5). These differences were relatively independent of perinatal risk status. Gender differences in the Griffiths GQ for ELBW infants are similar to expected differences for term infants and are unlikely to cause substantial bias in interpreting outcome studies for ELBW infants, unless these involve tests of specific cognitive abilities such as language.

Non-anaemic iron deficiency identified by ZPP test in extremely premature infants: prevalence, dietary risk factors, and association with neurodevelopmental problems.

INTRODUCTION: The aims of this study were to determine, in a cohort of extremely premature infants, the prevalence of iron deficiency identified by zinc protoporphyrin/heme ratio (ZPP) testing, and its association with neurodevelopmental problems and dietary risk factors for iron deficiency. METHODS: Infants of less than 29 weeks' gestation or less than 1000 g birth weight were studied prospectively at a multidisciplinary follow-up clinic. Assessments were made at a corrected age of either 12 months (n=72) or 2 years (n=69). Physical examination, Griffiths Developmental Scale, and neurosensory-motor assessment were administered, information on diet and behaviour was obtained by questionnaire, and a fingerprick ZPP ratio was performed to identify iron deficiency. RESULTS: 18.4% of infants had positive ZPP tests. There was no significant association between a positive ZPP test result and dietary risk factors, or symptoms of lethargy, irritability or poor attention. In children without cerebral palsy, there was no difference on Griffiths scores or neurosensory-motor assessment between ZPP-positive and ZPP-negative groups. The diagnosis of cerebral palsy (n=12) was significantly associated with both a positive ZPP test and a lower Griffiths general quotient (GQ) score. CONCLUSIONS: Iron deficiency occurs commonly in extremely low birth weight (ELBW) children in early childhood, and is not predicted by dietary risk factors. The prevalence of iron deficiency is increased in ELBW children with cerebral palsy. Non-anaemic iron deficiency (NAID) does not impair development or significantly affect behaviour of ELBW subjects who do not have cerebral palsy.

Extremely low birth weight and control infants at 2 years corrected age: a comparison of intellectual abilities, motor performance, growth and health.

A 2-year cohort of 63 surviving extremely low birth weight (ELBW) infants was prospectively studied and 60 of these infants, together with 44 normal birth weight control infants, were assessed at 2 years of age for intellectual abilities, motor skills, growth and health. The total ELBW group differed significantly from controls on overall Griffiths developmental quotient (99.3 vs. 103.8 P = 0.02) and in the personal/social subscale (100.7 vs. 106.7 P = 0.01). A subset of 43 of the ELBW infants was identified as low risk at discharge. No statistically significant differences were present between the low risk ELBW subset and controls in intellectual abilities though both the total ELBW group and the low risk ELBW subset differed from controls in fine and gross motor abilities, and in weight at 2 years. The total ELBW group also experienced more frequent ill health and hospital readmission.

Characteristics at four months follow-up of infants born small for gestational age: a controlled study.

This prospective study compared 65 small-for-gestational-age (SGA) (birth weight < 3rd centile) and 71 control infants at a corrected age of 4 months. It was hypothesised that differences would exist in growth, development, temperament and minor neurological signs and that these would be predicted by type (proportional/disproportional) of growth restriction at birth and maternal mood disturbance at birth or at 4 months. Infants had a Griffith's developmental test and neuromotor assessment. Maternal mood and infant temperament were surveyed. Few differences were found between SGA and control infants. SGA infants showed catch-up growth with 63% being above the third percentile and 43% being above the tenth percentile for weight. SGA infants had lower Griffith's GQ scores (97 vs. 102, P = 0.02) and they were rated in temperament as more manageable than controls. There were no differences in subtle neuromotor signs. Neither type of SGA nor maternal mood disturbance at birth had prognostic significance for infant catch up growth, neuromotor scores, or temperament though level of maternal stress and anxiety at 4 months were related to lower GQ scores in SGA infants.

D-amphetamine and antipsychotic drug effects on latent inhibition in mice lacking dopamine D2 receptors.

Drugs that induce psychosis, such as D-amphetamine (AMP), and those that alleviate it, such as antipsychotics, are suggested to exert behavioral effects via dopamine receptor D2 (D2). All antipsychotic drugs are D2 antagonists, but D2 antagonism underlies the severe and debilitating side effects of these drugs; it is therefore important to know whether D2 is necessary for their behavioral effects. Using D2-null mice (Drd2-/-), we first investigated whether D2 is required for AMP disruption of latent inhibition (LI). LI is a process of learning to ignore irrelevant stimuli. Disruption of LI by AMP models impaired attention and abnormal salience allocation consequent to dysregulated dopamine relevant to schizophrenia. AMP disruption of LI was seen in both wild-type (WT) and Drd2-/-. This was in contrast to AMP-induced locomotor hyperactivity, which was reduced in Drd2-/-. AMP disruption of LI was attenuated in mice lacking dopamine receptor D1 (Drd1-/-), suggesting that D1 may play a role in AMP disruption of LI. Further supporting this possibility, we found that D1 antagonist SKF83566 attenuated AMP disruption of LI in WT. Remarkably, both haloperidol and clozapine attenuated AMP disruption of LI in Drd2-/-. This demonstrates that antipsychotic drugs can attenuate AMP disruption of learning to ignore irrelevant stimuli in the absence of D2 receptors. Data suggest that D2 is not essential either for AMP to disrupt or for antipsychotic drugs to reverse AMP disruption of learning to ignore irrelevant stimuli and further that D1 merits investigation in the mediation of AMP disruption of these processes.

Analysis of threshold-type behaviour in mathematical models of the intrusion of a novel macroparasite in a host colony.

Macroparasites include worms, ticks, mites, bugs and fleas. These parasites are well known to induce morbidity effects including a reduction in the hosts' reproductive output and survival. An important scenario is the introduction of a new macroparasite into an established host population which may be caused by the climate change and by the transport of domestic animals. The aim of the article is to demonstrate an interesting feature of this scenario using a mathematical model with four dimensionless parameters. Six possible scenarios of introducing a new macroparasite into a host colony, ranging from the elimination of the new pathogen, through guaranteed host and parasite coexistence, to the collapse of the host colony are distinguished. The threshold surfaces in the space of parameters which separate the different scenarios are found. Some special limit cases are discussed.

Family food behaviours and adolescents' overweight status: a mother-offspring link study.

BACKGROUND: The role of family food behaviours on weight status of family members is not well understood. The objective of this study was to examine the influence of some aspects of family food behaviours on adolescents overweight. METHOD: In a cross-sectional mother-child-linked study design, participants were a subsample of 3862 adolescents (51.9% boys) from the Mater hospital-University of Queensland Study of Pregnancy (MUSP), a longitudinal study of a birth cohort of 7,223 women and their offspring. Information on aspects of family food behaviours (family meal patterns and influences, frequency of family food consumption, and influences on family food selection) was collected by self reported questionnaires from mothers in a 14 years follow up (in 1994-1997) and other covariates at different stages of follow-ups. Body Mass Index of the adolescents was calculated using measured height and weight. RESULTS: Being overweight at 14 years had significant negative associations with mothers' report on the importance of family meals (OR=1.28), frequency of eating cake/biscuits (OR=1.71), and significant positive association with mothers' report on frequency of consumption of cooked vegetables (OR=1.32), soft drinks (OR=1.60) and importance of fattening of foods (OR=1.27). CONCLUSION: The study confirmed the importance of the family and some family food behaviours in shaping risk of being overweight amongst adolescents. Because of the cross-sectional nature of this study, we could not conclude that they had casual correlations. Comparison with the literature suggests that some of these effects may be specific to particular contexts, potentially affected by cultural and socio-economic differences.