Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector

In this Letter, we present the design and performance of the frequency-dependent squeezed vacuum source that will be used for the broadband quantum noise reduction of the Advanced Virgo Plus gravitational-wave detector in the upcoming observation run. The frequency-dependent squeezed field is generated by a phase rotation of a frequency-independent squeezed state through a 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB of generated squeezing, up to 5.6 dB of quantum noise suppression has been measured at high frequency while close to the filter cavity resonance frequency, the intracavity losses limit this value to about 2 dB. Frequency-dependent squeezing is produced with a rotation frequency stability of about 6 Hz rms, which is maintained over the long term. The achieved results fulfill the frequency dependent squeezed vacuum source requirements for Advanced Virgo Plus. With the current squeezing source, considering also the estimated squeezing degradation induced by the interferometer, we expect a reduction of the quantum shot noise and radiation pressure noise of up to 4.5 dB and 2 dB, respectively.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

High Work Demands and Depression: The Moderating Role of the Serotonin Transporter Gene (5-HTT) and Work Control

Background:

High work demands (i.e. a heavy workload, tight time pressures, conflicting work tasks) put individuals at high risk of depression. Our aim was to test whether the relationship between high work demands and depression is moderated by genetic vulnerability to depression and by work control.

Methods:

Participants are members of the Dunedin Study, a 1972-73 longitudinal birth cohort assessed most recently in 2004-2005, at age 32 (96% response rate). This analysis included all participants who were employed at age 32. Depression was measured using the Diagnostic Interview Schedule. Work demands and work control were assessed in an interview. Genetic vulnerability to stress was ascertained by the serotonin transporter gene (5-HTT).

Results:

Among individuals exposed to high work demands, symptoms of depression were significantly higher among those who carried two short alleles of the 5-HTT gene (‘s/s’ group) than among ‘l’ carriers (interaction between 5-HTT gene and work demands: β=4.22, se=1.86, p=0.02). However, this gene-environment interaction was only present among those individuals who had low control over their work (interaction between 5-HTT gene and high work demands: β: 7.21, se: 2.73, p=0.009), not among those who had high work control (interaction between 5-HTT gene and high work demands: β: 1.32, se: 2.53, p=0.60).

Conclusion:

Pending replication, the serotonin transporter gene appears to moderate the effects of high work demands on symptoms of depression. This gene-environment interaction is attenuated by high work control.

The Dunedin Multidisciplinary Health and Development Study: Oral health findings and their implications

Longitudinal research is needed to better understand the natural history of oral conditions and long-term health and social outcomes. Oral health data has been collected periodically in the Dunedin Multidisciplinary Health and Development Study for over 40 years. To date, 70+ peer-review articles on the Study's oral health-related findings have been published, providing insight into the natural history of oral conditions, risk factors, impacts on quality of life, and disparities in oral health. Some of these report new findings, while others build upon the existing body of evidence. This paper provides an overview of these findings and reflects on their public health implications and policy utility in New Zealand.

Genetics and Crime: Integrating New Genomic Discoveries Into Psychological Research About Antisocial Behavior

Drawing on psychological and sociological theories of crime causation, we tested the hypothesis that genetic risk for low educational attainment (assessed via a genome-wide polygenic score) is associated with criminal offending. We further tested hypotheses of how polygenic risk relates to the development of antisocial behavior from childhood through adulthood. Across the Dunedin and Environmental Risk (E-Risk) birth cohorts of individuals growing up 20 years and 20,000 kilometers apart, education polygenic scores predicted risk of a criminal record with modest effects. Polygenic risk manifested during primary schooling in lower cognitive abilities, lower self-control, academic difficulties, and truancy, and it was associated with a life-course-persistent pattern of antisocial behavior that onsets in childhood and persists into adulthood. Crime is central in the nature-nurture debate, and findings reported here demonstrate how molecular-genetic discoveries can be incorporated into established theories of antisocial behavior. They also suggest that improving school experiences might prevent genetic influences on crime from unfolding.

Childhood body mass index and endothelial dysfunction evaluated by peripheral arterial tonometry in early midlife

BACKGROUND/OBJECTIVES

Endothelial dysfunction predicts mortality but it is unknown whether childhood obesity predicts adult endothelial dysfunction. The aim of this study was to determine whether anthropometric indices of body fat in childhood, adolescence and early midlife are associated with endothelial dysfunction in early midlife.

SUBJECTS/METHODS

Participants belonged to a representative birth cohort of 1037 individuals born in Dunedin, New Zealand in 1972 and 1973 and followed to age 38 years, with 95% retention (the Dunedin Multidisciplinary Health and Development Study). We assessed anthropometric indices of obesity at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, 26, 32 and 38 years. We tested associations between endothelial function assessed by peripheral arterial tonometry (PAT) at age 38 and; age 38 cardiovascular risk factors; age 3 body mass index (BMI); and four BMI trajectory groups from childhood to early midlife.

RESULTS

Early midlife endothelial dysfunction was associated with BMI, large waist circumference, low high-density lipoprotein cholesterol, low cardiorespiratory fitness and increased high-sensitivity C-reactive protein. After adjustment for sex and childhood socioeconomic status, 3-year-olds with BMI 1 s.d. above the mean had Framingham-reactive hyperemia index (F-RHI) ratios that were 0.10 below those with normal BMI (β=-0.10, 95% confidence interval (CI) -0.17 to -0.03, P=0.007) at age 38. Cohort members in the 'overweight', 'obese' and 'morbidly obese' trajectories had F-RHI ratios that were 0.08 (β=-0.08, 95% CI -0.14 to -0.03, P=0.003), 0.13 (β=-0.13, 95% CI -0.21 to -0.06, P<0.001) and 0.17 (β=-0.17, 95% CI -0.33 to -0.01, P=0.033), respectively, below age-peers in the 'normal' trajectory.

CONCLUSIONS

Childhood BMI and the trajectories of BMI from childhood to early midlife predict endothelial dysfunction evaluated by PAT in early midlife.

Life satisfaction and mental health problems (18 to 35 years)

BACKGROUND

Previous research has found that mental health is strongly associated with life satisfaction. In this study we examine associations between mental health problems and life satisfaction in a birth cohort studied from 18 to 35 years.

METHOD

Data were gathered during the Christchurch Health and Development Study, which is a longitudinal study of a birth cohort of 1265 children, born in Christchurch, New Zealand, in 1977. Assessments of psychiatric disorder (major depression, anxiety disorder, suicidality, alcohol dependence and illicit substance dependence) using DSM diagnostic criteria and life satisfaction were obtained at 18, 21, 25, 30 and 35 years.

RESULTS

Significant associations (p < 0.01) were found between repeated measures of life satisfaction and the psychiatric disorders major depression, anxiety disorder, suicidality, alcohol dependence and substance dependence. After adjustment for non-observed sources of confounding by fixed effects, statistically significant associations (p < 0.05) remained between life satisfaction and major depression, anxiety disorder, suicidality and substance dependence. Overall, those reporting three or more mental health disorders had mean life satisfaction scores that were nearly 0.60 standard deviations below those without mental health problems. A structural equation model examined the direction of causation between life satisfaction and mental health problems. Statistically significant (p < 0.05) reciprocal associations were found between life satisfaction and mental health problems.

CONCLUSIONS

After adjustment for confounding, robust and reciprocal associations were found between mental health problems and life satisfaction. Overall, this study showed evidence that life satisfaction influences mental disorder, and that mental disorder influences life satisfaction.

Specificity of childhood psychotic symptoms for predicting schizophrenia by 38 years of age: a birth cohort study

BACKGROUND

Childhood psychotic symptoms have been used as a subclinical phenotype of schizophrenia in etiological research and as a target for preventative interventions. However, recent studies have cast doubt on the specificity of these symptoms for schizophrenia, suggesting alternative outcomes such as anxiety and depression. Using a prospective longitudinal birth cohort we investigated whether childhood psychotic symptoms predicted a diagnosis of schizophrenia or other psychiatric disorders by 38 years of age.

METHOD

Participants were drawn from a birth cohort of 1037 children from Dunedin, New Zealand, who were followed prospectively to 38 years of age (96% retention rate). Structured clinical interviews were administered at age 11 to assess psychotic symptoms and study members underwent psychiatric assessments at ages 18, 21, 26, 32 and 38 to obtain past-year DSM-III-R/IV diagnoses and self-reports of attempted suicides since adolescence.

RESULTS

Psychotic symptoms at age 11 predicted elevated rates of research diagnoses of schizophrenia and posttraumatic stress disorder (PTSD) and also suicide attempts by age 38, even when controlling for gender, social class and childhood psychopathology. No significant associations were found for persistent anxiety, persistent depression, mania or persistent substance dependence. Very few of the children presenting with age-11 psychotic symptoms were free from disorder by age 38.

CONCLUSIONS

Childhood psychotic symptoms were not specific to a diagnosis of schizophrenia in adulthood and thus future studies of early symptoms should be cautious in extrapolating findings only to this clinical disorder. However, these symptoms may be useful as a marker of adult mental health problems more broadly.

Construct validity of Locker's global oral health item

With clinical oral examinations not always possible in health surveys, researchers may instead be invited to add questions to a wider health survey. In such situations, an item is needed which adequately represents both clinical and self-reported oral health. This study investigated the clinical validity of Locker's global self-reported oral health item among young middle-aged adults in populations in New Zealand and Australia. Clinical examination and self-report data (including the OHIP-14) were obtained from recent national dental surveys in NZ and Australia, and from age-38 assessments in the Dunedin Multidisciplinary Health and Development Study. National dataset analyses involved 35- to 44-year-olds. Caries and tooth-loss experience showed mostly consistent, statistically significant gradients across the Locker item responses; those responding 'Excellent' had the lowest scores, and those responding 'Poor' the highest. Periodontitis experience gradients in the NZ national sample were mainly as hypothesized; those rating their oral health as 'Poor' had the highest disease experience. OHIP-14 gradients across the Locker item responses were consistent and as hypothesized. The proportion of disease in the population borne by those 'Fair' or 'Poor' ranged from 26% to 72%. These findings provide preliminary support for the measure's validity as a global self-reported oral health measure in young middle-aged adults.

Risk factors prospectively associated with adult obsessive-compulsive symptom dimensions and obsessive-compulsive disorder

BACKGROUND

Very few longitudinal studies have evaluated prospective neurodevelopmental and psychosocial risk factors for obsessive-compulsive disorder (OCD). Furthermore, despite the heterogeneous nature of OCD, no research has examined risk factors for its primary symptom dimensions, such as contamination/washing.

METHOD

Potential risk factors for symptoms or diagnosis of OCD in adulthood and for specific adult obsessive-compulsive (OC) symptom dimensions were examined in the Dunedin Study birth cohort. The presence of obsessions and compulsions and psychological disorders was assessed using the Diagnostic Interview Schedule (DIS) at ages 26 and 32 years. Individuals with a diagnosis of OCD at either age (n=36) were compared to both a healthy control group (n=613) and an anxious control group (n=310) to determine whether associations between a risk factor and an OCD diagnosis were specific.

RESULTS

Childhood neurodevelopmental, behavioral, personality and environmental risk factors were associated with a diagnosis of OCD and with OC symptoms at ages 26 and 32. Social isolation, retrospectively reported physical abuse and negative emotionality were specific predictors of an adult OCD diagnosis. Of note, most risk factors were associated with OC symptoms in adulthood and several risk factors predicted specific OCD dimensions. Perinatal insults were linked to increased risk for symmetry/ordering and shameful thoughts dimensions, whereas poor childhood motor skills predicted the harm/checking dimension. Difficult temperament, internalizing symptoms and conduct problems in childhood also predicted specific symptom dimensions and lower IQ non-specifically predicted increased risk for most dimensions.

CONCLUSIONS

The current findings underscore the need for a dimensional approach in evaluating childhood risk factors for obsessions and compulsions.

Maternal oral health predicts their children's caries experience in adulthood

The long-term effects of poor maternal oral health are unknown. We determined whether maternal oral health when children were young was a risk indicator for caries experience in adulthood, using oral examination and interview data from age-5 and age-32 assessments in the Dunedin Study, and maternal self-rated oral health data from the age-5 assessment. The main outcome measure was probands' caries status at age 32. Analyses involved 835 individuals (82.3% of the surviving cohort) dentally examined at both ages, whose mothers were interviewed at the age-5 assessment. There was a consistent gradient in age-32 caries experience across the categories of maternal self-rated oral health status (from the age-5 assessment): it was greatest among the probands whose mothers rated their oral health as "poor" or who were edentulous, and lowest among those whose mothers rated their oral health as "excellent". Unfavorable maternal self-rated oral health when children are young should be regarded as a risk indicator for poor oral health among offspring as they reach adulthood.

How common are common mental disorders? Evidence that lifetime prevalence rates are doubled by prospective versus retrospective ascertainment

BACKGROUND

Most information about the lifetime prevalence of mental disorders comes from retrospective surveys, but how much these surveys have undercounted due to recall failure is unknown. We compared results from a prospective study with those from retrospective studies.

METHOD

The representative 1972-1973 Dunedin New Zealand birth cohort (n=1037) was followed to age 32 years with 96% retention, and compared to the national New Zealand Mental Health Survey (NZMHS) and two US National Comorbidity Surveys (NCS and NCS-R). Measures were research diagnoses of anxiety, depression, alcohol dependence and cannabis dependence from ages 18 to 32 years.

RESULTS

The prevalence of lifetime disorder to age 32 was approximately doubled in prospective as compared to retrospective data for all four disorder types. Moreover, across disorders, prospective measurement yielded a mean past-year-to-lifetime ratio of 38% whereas retrospective measurement yielded higher mean past-year-to-lifetime ratios of 57% (NZMHS, NCS-R) and 65% (NCS).

CONCLUSIONS

Prospective longitudinal studies complement retrospective surveys by providing unique information about lifetime prevalence. The experience of at least one episode of DSM-defined disorder during a lifetime may be far more common in the population than previously thought. Research should ask what this means for etiological theory, construct validity of the DSM approach, public perception of stigma, estimates of the burden of disease and public health policy.

Long-term dental visiting patterns and adult oral health

To date, the evidence supporting the benefits of dental visiting comes from cross-sectional studies. We investigated whether long-term routine dental visiting was associated with lower experience of dental caries and missing teeth, and better self-rated oral health, by age 32. A prospective cohort study in New Zealand examined 932 participants' use of dentistry at ages 15, 18, 26, and 32. At each age, routine attenders (RAs) were identified as those who (a) usually visited for a check-up, and (b) had made a dental visit during the previous 12 months. Routine attending prevalence fell from 82% at age 15 to 28% by 32. At any given age, routine attenders had better-than-average oral health, fewer had teeth missing due to caries, and they had lower mean DS and DMFS scores. By age 32, routine attenders had better self-reported oral health and less tooth loss and caries. The longer routine attendance was maintained, the stronger the effect. Routine dental attendance is associated with better oral health.

Trajectories of dental anxiety in a birth cohort

OBJECTIVE

To examine predictors of dental anxiety trajectories in a longitudinal study of New Zealanders.

METHODS

Prospective study of a complete birth cohort born in 1972/73 in Dunedin, New Zealand, with dental anxiety scale (DAS) scores and dental utilization determined at ages 15, 18, 26 and 32 years. Personality traits were assessed at a superfactor and (more fine-grained) subscale level via the Multidimensional Personality Questionnaire at age 18 years. Group-based trajectory analysis was used to identify dental anxiety trajectories.

RESULTS

DAS scores from at least three assessments were available for 828 participants. Six dental anxiety trajectories were observed: stable nonanxious low (39.6%); stable nonanxious medium (37.9%); recovery (1.6%); adult-onset anxious (7.7%); stable anxious (7.2%) and adolescent-onset anxious (5.9%). Multivariate analysis showed that males and those with higher DMFS at age 15 years were more likely to be in the stable nonanxious low trajectory group. Membership of the stable nonanxious medium group was predicted by the dental caries experience at age 15 years. Participants who had lost one or more teeth between ages 26 and 32 years had almost twice the relative risk for membership of the adult-onset anxious group. Personality traits predicted group membership. Specifically, high scorers (via median split) on the 'stress reaction' subscale had over twice the risk of being in the stable anxious group; low scorers on the traditionalism subscale were more likely to be members of the recovery trajectory group; and high scorers on the 'social closeness' subscale had half the risk of being in the stable anxious group. Dental caries experience at age 5 years was also a predictor for the stable anxious group. Membership of the late-adolescent-onset anxious group was predicted by higher dental caries experience by age 15 years, but none of the other predictors was significant.

CONCLUSION

Six discrete trajectories of dental anxiety have been observed. Some trajectories (totalling more than 90% of the cohort) had clear associations with external influences, but others were more strongly associated with characteristics such as personality traits. A mix of both influences was observed with only the stable anxious dental anxiety trajectory.

Effects of cannabis on lung function: a population-based cohort study

The effects of cannabis on lung function remain unclear and may be different from those of tobacco. We compared the associations between use of these substances and lung function in a population-based cohort (n = 1,037). Cannabis and tobacco use were reported at ages 18, 21, 26 and 32 yrs. Spirometry, plethysmography and carbon monoxide transfer factor were measured at 32 yrs. Associations between lung function and exposure to each substance were adjusted for exposure to the other substance. Cumulative cannabis use was associated with higher forced vital capacity, total lung capacity, functional residual capacity and residual volume. Cannabis was also associated with higher airway resistance but not with forced expiratory volume in 1 s, forced expiratory ratio or transfer factor. These findings were similar among those who did not smoke tobacco. In contrast, tobacco use was associated with lower forced expiratory volume in 1 s, lower forced expiratory ratio, lower transfer factor and higher static lung volumes, but not with airway resistance. Cannabis appears to have different effects on lung function from those of tobacco. Cannabis use was associated with higher lung volumes, suggesting hyperinflation and increased large-airways resistance, but there was little evidence for airflow obstruction or impairment of gas transfer.

The validity of the family history screen for assessing family history of mental disorders

There is a need to collect psychiatric family history information quickly and economically (e.g., for genome-wide studies and primary care practice). We sought to evaluate the validity of family history reports using a brief screening instrument, the Family History Screen (FHS). We assessed the validity of parents' reports of seven psychiatric disorders in their adult children probands from the Dunedin Study (n = 959, 52% male), using the proband's diagnosis as the criterion outcome. We also investigated whether there were informant characteristics that enhanced accuracy of reporting or were associated with reporting biases. Using reports from multiple informants, we obtained sensitivities ranging from 31.7% (alcohol dependence) to 60.0% (conduct disorder) and specificities ranging from 76.0% (major depressive episode) to 97.1% (suicide attempt). There was little evidence that any informant characteristics enhanced accuracy of reporting. However, three reporting biases were found: the probability of reporting disorder in the proband was greater for informants with versus without a disorder, for female versus male informants, and for younger versus older informants. We conclude that the FHS is as valid as other family history instruments (e.g., the FH-RDC, FISC), and its brief administration time makes it a cost-effective method for collecting family history data. To avoid biasing results, researchers who aim to compare groups in terms of their family history should ensure that the informants reporting on these groups do not differ in terms of age, sex or personal history of disorder.

Associations between birth weight, early childhood weight gain and adult lung function

BACKGROUND

Low birth weight is associated with lower values for spirometry in adults but it is not known if birth weight influences other measures of pulmonary function. It is also unclear whether postnatal growth affects adult lung function. The associations between birth weight, postnatal growth and adult lung function were assessed in an unselected birth cohort of 1037 children.

METHODS

Birth weight, weight gain between birth and age 3 years, and lung function at age 32 years were measured. Analyses were adjusted for adult height and sex and further adjusted for multiple other potential confounding factors.

RESULTS

Birth weight was positively correlated with spirometric (forced expiratory volume in 1 s and forced vital capacity) and plethysmographic (total lung capacity and functional residual capacity) lung function and with lung diffusing capacity. These associations persisted after adjustment for confounding factors including adult weight, exposure to cigarette smoke in utero and during childhood, personal smoking, socioeconomic status, asthma and gestational age. Weight gain between birth and age 3 years was also positively associated with lung diffusing capacity, and with higher values of lung volumes in men after adjustment for covariates. Neither birth weight nor postnatal weight gain was associated with airflow obstruction.

CONCLUSIONS

Low birth weight and lower weight gain in early childhood are associated with modest reductions in adult lung function across a broad range of measures of lung volumes and with lower diffusing capacity. These findings are independent of a number of potential confounding factors and support the hypothesis that fetal and infant growth is a determinant of adult lung function.

How should we construct psychiatric family history scores? A comparison of alternative approaches from the Dunedin Family Health History Study

BACKGROUND

There is increased interest in assessing the family history of psychiatric disorders for both genetic research and public health screening. It is unclear how best to combine family history reports into an overall score. We compare the predictive validity of different family history scores.

METHOD

Probands from the Dunedin Study (n=981, 51% male) had their family history assessed for nine different conditions. We computed four family history scores for each disorder: (1) a simple dichotomous categorization of whether or not probands had any disordered first-degree relatives; (2) the observed number of disordered first-degree relatives; (3) the proportion of first-degree relatives who are disordered; and (4) Reed's score, which expressed the observed number of disordered first-degree relatives in terms of the number expected given the age and sex of each relative. We compared the strength of association between each family history score and probands' disorder outcome.

RESULTS

Each score produced significant family history associations for all disorders. The scores that took account of the number of disordered relatives within families (i.e. the observed, proportion, and Reed's scores) produced significantly stronger associations than the dichotomous score for conduct disorder, alcohol dependence and smoking. Taking account of family size (i.e. using the proportion or Reed's score) produced stronger family history associations depending on the prevalence of the disorder among family members.

CONCLUSIONS

Dichotomous family history scores can be improved upon by considering the number of disordered relatives in a family and the population prevalence of the disorder.

Trajectory patterns of dental caries experience in the permanent dentition to the fourth decade of life

Dental caries is a chronic, cumulative disease, but no studies have investigated longitudinal patterns of caries experience. The objective of this study was to identify and describe developmental trajectories of caries experience in the permanent dentition to age 32. Longitudinal caries data for 955 participants in a longstanding birth cohort study were analyzed by trajectory analysis. Three caries experience trajectories were identified by the SAS macro PROC TRAJ; these were categorized as "high" (approximately 15%), "medium" (approximately 43%), and "low" (approximately 42%) DMFS (Decayed, Missing, and Filled Surfaces). All were relatively linear, although the higher trajectories were more "S-shaped". This effect disappeared following adjustment for the number of unaffected surfaces remaining at each age, suggesting that, among individuals following a similar caries trajectory, caries rate is relatively constant across time.

Psychosocial correlates of 6-n-propylthiouracil (PROP) ratings in a birth cohort

This study investigated the relation between ratings of 6-n-propylthiouracil (PROP) and two psychosocial constructs, socioeconomic status and IQ, which are related to health outcomes. A 3.2mM solution of PROP was rated by 922 32-year-old members of a birth cohort (450 women) relative to the strongest imaginable sensation of any kind using the generalised Labelled Magnitude Scale. Women had higher PROP ratings than men. Following normalisation of PROP ratings, multiple linear regression showed that higher ratings were independently associated with lower childhood socioeconomic status, lower childhood IQ scores and ratings of an imagined stimulus made on the same scale (r(2)=0.12). Results suggest that psychosocial variables, sex and scale use, in addition to established genetic determinants, may help explain variability in ratings of supra-threshold concentrations of PROP.

Changes in medication use from age 26 to 32 in a representative birth cohort

BACKGROUND

To date, longitudinal studies of medications have been confined to older adults or clinical samples, with no data from prospective studies of younger adults. The aim of the study was to examine changes in medication usage between ages 26 and 32 in a prospective study of a representative birth cohort.

METHODS

Medication use during the previous 2 weeks was investigated among 960 individuals at ages 26 and 32.

RESULTS

Nearly two-thirds took at least one medication at each age, with medication prevalence higher among women than among men. Three-quarters of those taking at least one at age 26 were doing so at 32. Over-the-counter medication prevalence increased from 35 to 43% between 26 and 32 years of age. Although the prevalence of prescribed medications decreased (from just under half to just over one-third, and from two-thirds to below half among women), there was no significant difference between the ages once hormonal contraceptives were accounted for. By 32, reduced usage of hormonal contraceptives was apparent, with one-third of age-26 users still taking these at 32. Other categories showing major changes were analgesics (increased), anti-asthma drugs (decreased), antidepressants (increased) and antiulcer drugs (increased). At 32, 82% of those taking analgesics, 85% of those taking nutrient supplements, 71% of those taking antihistamines and 33% of those taking antiulcer drugs had self-prescribed them.

CONCLUSION

A considerable proportion of the sample used medications by age 32, and there was considerable change between 26 and 32. The changes are likely to have been due to a mix of ageing and period effects.

Progression of dental caries and tooth loss between the third and fourth decades of life: a birth cohort study

The majority of what is known of the experience of dental caries among adults is from cross-sectional studies, and there are surprisingly few population-level longitudinal studies of dental caries among adults. Dental examinations were conducted at age 26 and again at age 32 among participants in a longstanding prospective study of a birth cohort born in Dunedin (New Zealand) in 1972/1973. Some 901 individuals (88.8%) were dentally examined at both ages. The mean number of remaining teeth and tooth surfaces fell between 26 and 32, reflecting ongoing tooth loss. The overall prevalence of caries rose from 94.9 to 96.8%, while there were greater increases in the proportion with caries-associated tooth loss (from 10.8 to 22.8%). Caries experience was greatest in the molar teeth and upper premolars, and was lowest in the lower anterior teeth. The mean crude caries increment (CCI) was 5.0 surfaces (SD 6.6); 681 (75.5%) experienced 1+ CCI, and the mean CCI among those individuals was 6.6 surfaces (SD 6.9). Substantial dental caries and tooth loss experience occur as people move from the third into the fourth decade of life.

Oral health beliefs in adolescence and oral health in young adulthood

According to theory, health beliefs are related to health behaviors. We investigated whether individuals who hold favorable oral-health-related beliefs over time have better adult oral health than those who do not. Beliefs about the efficacy of water fluoridation, keeping the mouth clean, avoiding sweet foods, visiting the dentist, using dental floss, and using fluoridated toothpaste were assessed in a birth cohort at ages 15, 18, and 26 years. At each age, the majority of participants endorsed the importance of each practice. However, there was also evidence of instability across time. Individuals who held stable favorable dental beliefs from adolescence through adulthood had fewer teeth missing due to caries, less periodontal disease, better oral hygiene, better self-rated oral health, and more restorations. Dental beliefs can change between adolescence and young adulthood, and these changes are related to oral health. In particular, unfavorable dental health beliefs are related to poorer oral health.

Watching television is associated with childhood obesity: but is it clinically important?

OBJECTIVE

To assess the impact of television viewing during childhood and adolescence on body mass index (BMI) in children up to the age of 15 years.

DESIGN

Unselected birth cohort, assessed at birth and every 2 years from age 3 to 15 years.

SUBJECTS

In all, 1037 individuals were assessed at age 3 years. At age 15 years, 976 (95% of living cohort) continued to participate.

MEASUREMENTS

Parental estimates of weekday television viewing between age 5 and 11 years. Self-reports of television viewing at age 13 and 15 years. Weight and height were measured at each age to calculate BMI.

RESULTS

BMI and prevalence of overweight at all ages were significantly associated with mean hours of television viewing reported in the assessments up to that age. These associations were stronger in girls than boys. The associations remained significant after adjusting for parental body mass indices and socio-economic status.

CONCLUSION

Time spent watching television is a significant predictor of BMI and overweight in childhood. Although the effect size appears small, it is larger than the effect sizes commonly reported for nutritional intake and physical activity. Television viewing should be regarded as an important contributing factor to childhood obesity.

Breast feeding is related to C reactive protein concentration in adult women

OBJECTIVE

To assess the influence of infant breast feeding on C reactive protein (CRP), a marker of low grade inflammation associated with cardiovascular mortality independent of serum cholesterol concentrations.

DESIGN

Serum CRP, total cholesterol, anthropometric, and blood pressure measurements were performed along with assessment of infant breast feeding duration, birth weight, smoking status, adult socioeconomic status, number of health problems, and hormonal contraceptive use.

SETTING

A New Zealand predominantly European descent community birth cohort.

PARTICIPANTS

822 men and women aged 26 years.

MAIN RESULTS

There was a significant linear relation (p<0.001) between duration of breast feeding and adult CRP level in women. The geometric means (IQR) for CRP were 2.22 (1, 4) mg/l for women breast fed for six months or more and 3.95 (2, 8) mg/l for women not breast fed (ratio, 95% confidence interval (CI): 0.69 (0.55 to 0.87). The linear association between cholesterol and breast feeding was also significant (p = 0.01), the geometric mean (IQR) total cholesterol levels being 4.62 (4.10, 5.10) for those breast fed for six months or more and 5.04 (4.5, 5.80) for those not breast fed (ratio, 95% CI: 0.92 (0.87, 0.98). There was no relation between CRP or total cholesterol and duration of breast feeding in men.

CONCLUSIONS

The findings of lower CRP with an increased duration of breast feeding in women suggest early postnatal nutrition may influence long term cardiovascular risk.

Socioeconomic inequalities in oral health in childhood and adulthood in a birth cohort

OBJECTIVES

To determine whether adult oral health is predicted by (a) childhood socioeconomic advantage or disadvantage (controlling for childhood oral health), or (b) oral health in childhood (controlling for childhood socioeconomic advantage or disadvantage), and whether oral health in adulthood is affected by changes in socioeconomic status (SES).

METHODS

Participants in a longstanding cohort study underwent systematic dental examination for dental caries and tooth loss at ages 5 and 26 years. The examination at age 26 years included the collection of data on periodontal attachment loss and plaque level. Childhood SES was determined using parental occupation, and adult SES was determined from each study member's occupation at age 26 years. Regression models were used to test the study hypotheses.

RESULTS

Complete data were available for 789 individuals (47.4% female). After controlling for childhood oral health, those who were of low SES at age 5 years had substantially greater mean DFS and DS scores by age 26 years, were more likely to have lost a tooth in adulthood because of caries, and had greater prevalence and extent of periodontitis. A largely similar pattern was observed (after controlling for childhood SES) among those with greater caries experience at age 5 years. For almost all oral health indicators examined, a clear gradient was observed of greater disease at age 26 years across socioeconomic trajectory groups, in the following order of ascending disease severity and prevalence: 'high-high', 'low-high' (upwardly mobile), 'high-low' (downwardly mobile) and 'low-low'.

CONCLUSION

Adult oral health is predicted by not only childhood socioeconomic advantage or disadvantage, but also by oral health in childhood. Changes in socioeconomic advantage or disadvantage are associated with differing levels of oral health in adulthood. The life-course approach appears to be a useful paradigm for understanding oral health disparities.

Association between C-reactive protein, metabolic cardiovascular risk factors, obesity and oral contraceptive use in young adults

OBJECTIVE

This study sought to determine the relationship between levels of the inflammatory marker, C-reactive protein (CRP), cardiovascular risk factors and oral contraceptive use in young adults.

DESIGN

Cross-sectional study of a community cohort.

SUBJECTS

A total of 822 men and women aged 26 y.

MEASUREMENTS

CRP, body mass index (BMI), blood pressure, lipid and lipoprotein levels, smoking status, socioeconomic status, health status, and hormonal contraceptive use in women.

RESULTS

Multiple regression analysis showed that obesity was independently related to CRP with an increase in ratio CRP of 1.03 (95% CI 1.01, 1.05) for men and 1.07 (1.05, 1.09) for women associated with a 1 kg/m(2) increase in BMI. In women, combined oral contraceptive use was associated with a ratio change in CRP of 1.52 (1.27, 1.82) compared with nonusers. Other independent determinants of CRP in men and women were apolipoprotein B level, systolic blood pressure and apolipoprotein A1 in men. Univariate analysis showed that the relationship between CRP and BMI, systolic blood pressure and apolipoprotein B was significantly stronger in women than men.

CONCLUSION

These findings suggest that obesity is associated with inflammation independent of other cardiovascular risk factors that may contribute to an increased risk for cardiovascular disease in men and women. Elevated CRP related to combined oral contraceptive use may influence the rate of cardiovascular events in young women.

Relationship between socioeconomic status and asthma: a longitudinal cohort study

BACKGROUND

There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors.

METHODS

We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models.

RESULTS

No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports.

CONCLUSIONS

Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding.

The dopamine D4 receptor and the hyperactivity phenotype: a developmental-epidemiological study

Attention-deficit hyperactivity disorder (ADHD) affects 2-6% of school-age children and is a precursor of behavioural problems in adolescence and adulthood. Underlying the categorical definition of ADHD are the quantitative traits of activity, impulsivity, and inattention which vary continuously in the population. Both ADHD and quantitative measures of hyperactivity are heritable, and influenced by multiple genes of small effect. Several studies have reported an association between clinically defined ADHD and the seven-repeat allele of a 48-bp tandem repeat polymorphism in the third exon of the dopamine D4 receptor gene (DRD4). We tested this association in a large, unselected birth cohort (n = 1037) using multiple measures of the hyperactivity phenotype taken at multiple assessment ages across 20 years. This longitudinal approach allowed us to ascertain whether or not DRD4 has a general effect on the diagnosed (n = 49) or continuously distributed hyperactivity phenotype, and related personality traits. We found no evidence to support this association.

Medications taken by 26-year-olds

BACKGROUND

Most descriptive pharmacoepidemiological reports are from studies of older people, and little is known about medication use by younger adults.

AIMS

The aim of the present study was to examine the prevalence of medication usage in the previous 2 weeks among young adults.

METHODS

Detailed information was collected on medications taken by 26-year-old participants in the longstanding Dunedin Multidisciplinary Health and Development Study.

RESULTS

At age 26, 980 (96.2%) of the surviving cohort participated; medication data were available for 978 individuals, of whom 78.1% had taken one or more prescribed or over-the-counter medications. Medication use was higher among females. The most prevalent drug categories were analgesics (taken by 22.8% of the sample), hormonal contraceptives (21.9%; 44.7% of females), nutrient supplements (17.6%) and anti-asthma drugs (11.1%).

CONCLUSIONS

The prevalence and pattern of medication use among younger adults differ from those reported for older age groups. Asthma appears to be the most prevalent chronic medical condition requiring pharmacological intervention (and for which medical care has been sought) among younger adults. The low rates of use of antidepressants and anxiolytics suggest that common psychiatric disorders may currently go unrecognized or untreated among young adults, and the high prevalence of 'third generation' oral contraceptive use among females is of particular concern.

Physical and psychological correlates of primary headache in young adulthood: a 26 year longitudinal study

OBJECTIVES

To determine if physical and/or psychological risk factors could differentiate between subtypes of primary headache (migraine, tension-type headache (TTH), and coexisting migraine and TTH (combined)) among members of a longitudinal birth cohort study.

METHODS

At age 26, the headache status of members of the Dunedin Multidisciplinary Health and Development Study (DMHDS) was determined using International Headache Society criteria. Headache history and potential physical and psychological correlates of headache were assessed. These factors included perinatal problems and injuries sustained to age 26; and behavioural, personality, and psychiatric disorders assessed between ages 5 to 21.

RESULTS

The 1 year prevalences for migraine, TTH, and combined headache at the age of 26 were 7.2%, 11.1%, and 4.3%, respectively. Migraine was related to maternal headache, anxiety symptoms in childhood, anxiety disorders during adolescence and young adulthood, and the stress reactivity personality trait at the age of 18. TTH was significantly associated with neck or back injury in childhood (before the age of 13). Combined headache was related to maternal headache and anxiety disorder at 18 and 21 only among women with a childhood history of headache. Headache status at the age of 26 was unrelated to a history of perinatal complication, neurological disorder, or mild traumatic head injury.

CONCLUSIONS

Migraine and TTH seem to be distinct disorders with different developmental characteristics. Combined headache may also have a distinct aetiology.

Persistence and perceived consequences of cannabis use and dependence among young adults: implications for policy

AIMS

To document patterns of cannabis use and dependence from late-adolescence through to the mid-twenties; to describe perceived consequences of cannabis use among young people; and to consider policy implications of these findings.

METHODS

This was a longitudinal study of the Dunedin Multidisciplinary Health and Development Study birth cohort with repeated measures of cannabis use at ages 18, 21 and 26 years.

RESULTS

Twelve month prevalence rates of cannabis use (just over 50%) and dependence (just under 10%) remained stable between age 21 and 26 years, contrary to an expected decline. Cannabis dependence, as distinct from occasional use, was associated with high rates of harder drug use, selling of drugs and drug conviction. Cumulatively, almost 3/4 of our cohort had tried cannabis by age 26. Young people thought the risk of getting caught using cannabis was trivial, and that using cannabis had few negative social consequences.

CONCLUSIONS

The persistent high rates of cannabis use and dependence among young New Zealand adults raises important issues for policy makers. Current laws are not particularly effective in deterring use. Whereas occasional use does not appear to present a serious problem, cannabis dependence among users is a serious public health issue that warrants immediate action.

A longitudinal study of the etiology of separation anxiety

A longitudinal examination of the relation between separation experiences and the development of separation anxiety at age 3, 11 and 18 years was conducted. Three associative pathways were assessed. Conditioning events were not related to separation anxiety at age 3. Vicarious learning (modelling) in middle childhood (age 9 years) was the conditioning variable most strongly related to separation anxiety at age 11, accounting for 1.8% of the variance in symptoms. Separation experiences (hospitalisations) before the age of 9 were inversely correlated with separation anxiety at age 18. That is, more overnight hospital stays in childhood were related to less separation anxiety in late adolescence. However, none of these conditioning correlates remained significant predictors of separation anxiety in adjusted regression models. In contrast, certain "planned" separations in early-mid childhood were associated with lower levels of separation anxiety at later ages. Generally, the findings were consistent with predictions from the non-associative theory of fear acquisition. That vicarious learning processes appeared to modulate, albeit to a minor degree, the expression of separation anxiety during mid-late childhood suggests that there may be critical periods during which some individuals are susceptible to the interactive effects of both associative and non-associative processes. These findings serve to illustrate the complexity of fear acquisition, the relevance of developmental factors and the likely interplay between associative and non-associative processes in the etiology of fear and anxiety.

Psychological disorders and dental anxiety in a young adult population

OBJECTIVES

It has been suggested that some individuals who are fearful or anxious about dental treatment have a constitutional vulnerability to anxiety disorders as evidenced by the presence of multiple fears, generalized anxiety or panic disorders. This paper compares the prevalence of psychological disorders among dentally anxious and non-anxious groups drawn from the general population.

METHODS

Data were obtained as part of a birth cohort study when study members were aged 18 years. They were assessed using the Dental Anxiety Scale (DAS) and the Diagnostic Interview Schedule (DIS). The disorders diagnosed by the DIS were major depressive episode, dysthymia, generalized anxiety disorder, panic disorder, agoraphobia, social phobia, simple phobia, obsessive compulsive disorder, conduct disorder, cannabis and alcohol dependence.

RESULTS

Overall, 12.5% of study members had DAS scores of 13 or more and were considered to be dentally anxious. Those who were dentally anxious were more likely than the non-anxious to be diagnosed with one or more psychological disorders (55.0% vs. 42.3%). However, those with DAS scores of 13 or 14 (moderately dentally anxious) were broadly similar to the non-anxious in terms of their psychological profile. This excess prevalence of psychological disorder was largely accounted for by high rates of disorder among those with DAS scores of 15 or more (highly dentally anxious). The highly anxious were more likely than the non-anxious to have a diagnosis of conduct disorder, agoraphobia, social phobia, simple phobia or alcohol dependence. Odds ratios ranged from 2.8 to 5.0 after controlling for the effects of gender. The data also suggested that dentally anxious individuals with psychological disorders were more likely to maintain their anxiety over time.

CONCLUSIONS

In this population of young adults, high rates of psychological disorder were characteristic of those with high levels of dental anxiety. Psychological disorder was related to the maintenance of dental anxiety over time.

Brain drain or OE? Characteristics of young New Zealanders who leave

AIMS

To characterise the emigration patterns of young New Zealanders.

METHODS

The 980 members of the Dunedin Multidisciplinary Health and Development Study participating in the "age-26" (1998-1999) assessment provided information about emigration behaviour, qualifications, aspects of physical and mental health and personality.

RESULTS

26% of the sample had moved overseas to live between the ages of 18 and 26, with the United Kingdom and Australia being the most common destinations. Compared to non-emigrants, emigrants had higher IQ scores, were better qualified, leaner and fitter, and had happier and less stress-prone personalities. Based on their planned return date, 63% of emigrants were considered to be on their OE overseas experience (OE, return in <5 years), 18% were defined as brain-drain emigrants (return in >5 years or never) and 18% were uncertain about their return. Brain-drain emigrants were more likely than OE emigrants to leave for better work opportunities, and they were also more likely to go to Australia. However, there were no differences in terms of qualifications, intelligence and personality between OE and brain-drain emigrants.

CONCLUSIONS

Most young New Zealanders in this cohort who left for overseas were embarking on their OE. Brain-drain emigrants make up a sizeable minority of emigrants, but appear to possess no more skills than those who plan or choose to return.

Nicotine dependence and attempts to quit or cut down among young adult smokers

AIMS

To describe tobacco smoking behaviours, attempts to cut down or quit, and estimate the prevalence of DSM-IV nicotine dependence among young adult smokers. To relate these findings to population demand for national Quitline services.

METHODS

Confidential interviews were conducted during the assessment of the Dunedin Multidisciplinary Health and Development Study birth cohort at age 26 years. Current smokers who had smoked daily for at least one month during the twelve months before interview were asked questions to identify nicotine dependence, based on DSM-IV criteria.

RESULTS

Overall, 40% (n = 386) of the cohort followed up were current smokers who met the twelve month daily smoking criterion, one third of whom fulfilled DSM-IV criteria for nicotine dependence. The mean number of attempts to quit or cut down in the past year was 1.2. Assuming that each attempt represents a potential call to the Quitline, more than 5500 calls per month might be anticipated from the 25-29 year age group and in excess of 40 000 from the total New Zealand population, eighteen years and older.

CONCLUSIONS

Results indicate that many young adult smokers are potential users of smoking cessation services and many are nicotine dependent. In order to satisfy this reservoir of need and reduce the population burden of ill-health and premature death due to tobacco smoking, resources should continue to be provided to support and enhance tobacco control programmes with proven effectiveness in helping smokers to quit.

IL-1 genotype and adult periodontitis among young New Zealanders

Several recent studies have investigated the association between interleukin-1 genotype and periodontitis in clinical samples, where generalizability is an issue. The aim of this study was to investigate the association between adult periodontitis and IL-1 genotype in a population-based sample of 26-year-olds. Based on probing depth (PD) measurements, participants were divided into three disease groups: "Severe" (1+ teeth with 5+mm PD; N = 25), "Moderate" (2+ teeth with 4+mm PD; N = 36), and "Controls" (the remainder; N = 800). The "periodontitis-associated genotype" (PAG; Kornman et al., 1997) was present in 20.0% of the "Severe" group and in 34.8% of "Controls", whereas the IL-1A(+4845) [1,1]/IL-1B(+3953) [2,2] genotype was present in 12.0% and 0.9%, respectively. After controlling for sex, smoking status, and plaque levels, we found that those with IL-1B(+3953) [1,1]/IL-1A(+4845) [2,2] had 12.3 times the odds of being in the "Severe" group. Analysis of these data suggests that the IL-1A(+4845) [1,1]/IL-1B(+3953) [2,2] genotype is associated with periodontal disease in this young population. Future periodontal data collections as this cohort ages are required to confirm the predictive value of that genotype.

Determinants of early- vs late-onset dental fear in a longitudinal-epidemiological study

A longitudinal investigation of risk factors for early- and late-onset dental fear was conducted. Early-onset dental fear was related to conditioning experiences (indexed via caries level and tooth loss), service use patterns, stress reactive personality and specific beliefs about health professionals. Late-onset dental fear was related to aversive conditioning experiences, irregular service use and an external locus of control. In contrast to recent findings for dental anxiety, personality factors were not strongly related to the onset of dental fear in young adulthood. The key role played by conditioning events in the development of both early- and late-onset dental fear was confirmed. Conditioning events appear to play a different role in the development of dental fear vs dental anxiety. This may reflect important, but largely ignored differences between these two closely-related constructs. Interventions for early-onset dental fear should aim to modify both the dental fear and the personality vulnerabilities that may contribute to the development of dental fear early in the life-course.

Psychological disorder, conditioning experiences, and the onset of dental anxiety in early adulthood

Most studies examining the origins of dental fear and anxiety have relied on cross-sectional data. These are subject to several problems, such as recall and uncertainty concerning temporal relationships. This paper uses longitudinal data from the Dunedin Multidisciplinary Health and Development Study to assess risk factors for the development of dental anxiety in persons between the ages of 18 and 26 years. It was hypothesized that psychological factors would be as important as conditioning experiences in the genesis of dental anxiety over this period. The eight-year incidence of dental anxiety was 16.5%. Five variables entered models predicting onset: multiple fears, symptoms of substance dependence, previous experience of invasive dental treatment, dental visiting pattern, and the extraction of one or more teeth. Separate analyses for those avoiding and those using dental services resulted in different explanatory models. These results indicated that both psychological and conditioning variables contributed to the development of dental anxiety in this population of young adults.

Onset of and patterns of change in dental anxiety in adolescence and early adulthood: a birth cohort study

OBJECTIVE

To assess the onset of and patterns of change in dental anxiety during adolescence and early adulthood.

DESIGN

A birth cohort study of 1,037 individuals born in Queen Mary Hospital, Dunedin, New Zealand between 1 April 1972 and 31 March 1973. Data were collected from these individuals at birth, every two years between the ages of 3 and 15 and at 18, 21 and 26 years. STUDY MEMBERS: Data on dental anxiety were obtained at the 15, 18 and 26-year assessments from 678 study members.

OUTCOMES

Dental anxiety was assessed using the Dental Anxiety Scale. Study members with a score of 13 or over were classified as being dentally anxious.

RESULTS

The prevalence of dental anxiety increased from 10.6% at age 15 years to 13.3% at 18 years and 21.1% at 26 years. Of the 31.2% who were anxious at one or more data collection periods, approximately one third were anxious by the age of 15, one third became anxious between 16 and 18 years and one third between 18 and 26 years. High rates of remission were observed. Of 72 study members who were dentally anxious at 15 years, 22% were persistent cases, anxious at all three data collection points; 24% were recurrent cases, anxious at 26 but not anxious at 18 years; and 54% were remitted cases, no longer anxious at 26 years. There were no gender differences in the onset and course of dental anxiety over the developmental periods observed.

CONCLUSIONS

The period of observation was one of instability with respect to anxiety about dental treatment. Early adulthood in particular appeared to be a life stage during which this population was vulnerable to the onset of dental anxiety. This may be related to dental disease and treatment factors, or changing psychological states during significant life transitions.

Paths to panic disorder/agoraphobia: an exploratory analysis from age 3 to 21 in an unselected birth cohort

OBJECTIVE

To evaluate childhood temperamental traits and early illness experiences in the etiology of adult panic disorder with agoraphobia.

METHOD

Evaluated temperamental and illness experience factors, at ages 3 through 18, as predictors of panic and agoraphobia at ages 18 or 21 in an unselected sample (N = 992). Analyses were conducted with classification trees.

RESULTS

Experience with respiratory ill health predicted panic/agoraphobia relative to other anxiety disorders and healthy controls. Also, temperamental emotional reactivity at age 3 predicted panic/agoraphobia in males but did not predict other anxiety disorders, compared with healthy controls. Furthermore, temperament and ill health interacted with gender.

CONCLUSIONS

Results are discussed in terms of cognitive theories of fear of physical symptoms and biological models of respiratory disturbance for panic/agoraphobia.

The irritable bowel syndrome and psychiatric disorders in the community: is there a link?

OBJECTIVE

Psychiatric morbidity is high among patients who present to referral centers with irritable bowel syndrome (IBS). However, few studies have investigated the relationship between psychiatric disturbance and IBS in community samples. We hypothesized that psychiatric disorders are linked to IBS in the general community, but this is influenced by the criteria used to establish a diagnosis of IBS.

METHODS

The data were collected from a birth cohort born in Dunedin (New Zealand) between April 1972 and March 1973. This cohort consisted of 1037 members (52% male), who were assessed at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, and 26 yr. GI symptoms were recorded at age 26 yr, using an abbreviated version of the Bowel Symptom Questionnaire; psychiatric history was obtained at ages 18 and 21 yr, using a modified version of the Diagnostic Interview Schedule.

RESULTS

The prevalence of IBS was 12.7% according to the Manning criteria and 4.3% according to the Rome II criteria. The IBS was not significantly related to a diagnostic history for psychiatric illness overall, nor to a history of anxiety disorders, depressive disorders, and substance dependence. These results were independent of the IBS criteria used; there was no association between psychiatric history and IBS when IBS was defined according to the Manning criteria (p = 0.11 to 0.98) or the Rome criteria (p = 0.18 to 0.92): Rome and Manning criteria subjects did not significantly differ from each other in terms of psychiatric history (p = 0.16 to 0.89).

CONCLUSION

In a cohort of young adults with IBS from New Zealand, IBS appears to not be related to psychiatric disorders.

Failure to overcome 'innate' fear: a developmental test of the non-associative model of fear acquisition

The non-associative, Darwinian theory of fear acquisition proposes that some individuals fail to overcome biologically-relevant fears (e.g. height) because they (1) do not have sufficient safe exposure to the relevant stimuli early in life or (2) are poor habituators who have difficulty 'learning not to fear'. These two hypotheses were tested in a longitudinal birth cohort study. Study 1 found evidence for reduced exposure to height stimuli in childhood for individuals with a fear of heights compared to study members without fear. Study 2 found evidence for higher levels of stress reactivity (a proxy for habituation) in childhood and adolescence among 18-year-old height phobics compared to study members with dental phobia and those with no fear. The results were discussed in relation to recent findings suggesting that some evolutionary-relevant fears may appear in the absence of traumatic 'learning' experiences. The merits of adding a fourth, non-associative pathway to Rachman's [Rachman, S. (1977)]. The conditioning theory of fear acquisition: a critical examination. Behaviour Research and Therapy, 15, 375-387) three pathways model of fear acquisition were briefly considered.