Integrating Diversity, Equity, and Inclusion into Preclinical, Clinical, and Public Health Mathematical Models

Mathematical modelling applied to preclinical, clinical, and public health research is critical for our understanding of a multitude of biological principles. Biology is fundamentally heterogeneous, and mathematical modelling must meet the challenge of variability head on to ensure the principles of diversity, equity, and inclusion (DEI) are integrated into quantitative analyses. Here we provide a follow-up perspective on the DEI plenary session held at the 2023 Society for Mathematical Biology Annual Meeting to discuss key issues for the increased integration of DEI in mathematical modelling in biology.

Childhood disadvantage and adolescent socioemotional wellbeing as predictors of future parenting behaviour

INTRODUCTION

In extending work on early life antecedents of parenting, we investigate associations between childhood family history of disadvantage, adolescent socioemotional wellbeing, and age at first parenthood and subsequent parenting behaviour.

METHODS

Parent-child interactions were recorded when participants in the longitudinal Dunedin Multidisciplinary Health and Development Study (New Zealand) had a three-year-old child. Data were available for 358 mothers and 321 fathers, aged between 17.7 and 41.5 at the time of their child's birth. Associations between parenting and antecedent data on socioeconomic disadvantage, adolescent wellbeing and mental health, as well as current adult mental health and age at parenting, were tested for using structural equation modelling.

RESULTS

Family disadvantage in childhood and lower adolescent wellbeing was associated with less positive future parenting, but only adult (not adolescent) anxiety/depression symptoms were directly associated with parenting behaviour. Childhood family disadvantage was associated with further disadvantage across the life course that included less positive parenting of the next generation. In contrast, socioemotional wellbeing during adolescence and later age of onset of parenting were associated with more positive parenting.

CONCLUSIONS

Reducing childhood disadvantage and improving socioemotional wellbeing during childhood and adolescence is likely to have intergenerational benefits through better parenting of the next generation.

First Report of Dodder (Cuscuta pentagona) on Chickpea (Cicer arietinum) in the United States

Chickpea (Cicer arietinum L.) is an important rotational and an emerging specialty crop in the Pacific Northwest of the United States, in California, and in the Northern Great Plains of the United States and Canada. Dodders (Cuscuta spp.) are widespread parasitic weeds on many crops worldwide. Several Cuscuta species (primarily C. campestris Yuncker) have been reported to parasitize chickpea, and dodder is important on chickpea in the Indian subcontinent, the Middle East, and recently in Australia (4), but has previously not been reported from North America. On 28 July 2012, a chickpea field near Walla Walla, WA, was found parasitized by dodder. The chickpea was at late flowering and early pod filling stages and there were no other visible green weedy plants as observed from the canopy. There were about 15 dodder colonies varying in size from 2 to 15 meters in diameter in the field of about 500 acres. Chickpea plants in the center of the dodder colonies were wilting or dead. The colonies consisted of orange leafless twining stems wrapped around chickpea stems and spreading between chickpea plants. Haustoria of the dodder penetrating chickpea stems were clearly visible to the naked eye. Flowers, formed abundantly in dense clusters, were white and five-angled, with capitate stigmas, and lobes on developing calyxes were clearly overlapping. The dodder keyed to C. pentagona Engelm. in Hitchcock and Cronquest (3) and in Costea (1; and www.wlu.ca/page.php?grp_id=2147&p=8968 ). Specimens of dodder plants wrapping around chickpea stems with visible penetrating haustoria were collected on 28 July 2013 and vouchers (WS386115, WS386116, and WS386117) were deposited at the Washington State University Ownbey Herbarium. All dodder colonies in the field were eradicated before seed formation to prevent establishment of dodder. Total genomic DNA was isolated from dodder stems, and PCR primers ITS1 (5'TCCGTAGGTGAACCTGCGG) and ITS4 (5'TCCTCCGCTTATTGATATGC) were used to amplify the internal transcribed spacer (ITS) region of the nuclear rDNA. The ITS region was sequenced. BLAST search of the NCBI nucleotide database using the ITS sequence as query found that the most similar sequence was from C. pentagona (GenBank Accession No. DQ211589.1), and our ITS sequence was deposited in GenBank (KC832885). Dodder (C. approximata Bab.) has been historically a regional problem on alfalfa (Washington State Noxious Weed Control Board 2011). Another species stated to be "mainly" associated with legumes is C. epithymum Murr., and C. pentagona is "especially" associated with legumes (3). The latter species has sometimes been considered a variety (var. calycina) of C. campestris Yuncker (1,3). Although chickpea has been cultivated in the Walla Walla region for over 20 years, to our knowledge, this is the first time dodder has been observed on chickpea in North America. The likely source is from nearby alfalfa or other crop fields, with transmission by farm machinery or wild animals. Some chickpea germplasm exhibits partial resistance to C. campestris (2). References: (1) M. Costea et al. SIDA 22:151, 2006. (2) Y. Goldwasser et al. Weed Res. 52:122, 2012. (3) C. L. Hitchcock and A. Cronquist. Flora of the Pacific Northwest: An Illustrated Manual. University of Washington Press, Seattle, 1973. (4) D. Rubiales et al. Dodder. Page 98 in: Compendium of Chickpea and Lentil Diseases and Pests. W. Chen et al., eds. APS Press, St. Paul, Minnesota, 2011.

Comparison of seasonal phenol and p-cresol emissions from ground-level area sources in a dairy operation in central Texas

Although there are more than 200 odor-causing volatile organic compounds (VOCs), phenol and p-cresol are two prominent odor-causing VOCs found downwind from concentrated animal feeding operations (CAFOs). The VOC emissions from cattle and dairy production are difficult to quantify accurately because of their low concentrations, spatial variability, and limitations of available instruments. To quantify VOCs, a protocol following US. Environmental Protection Agency (EPA) Method TO-14A has been established based on the isolation flux chamber method and a portable gas chromatograph (GC) coupled with a purge-and-trap system. The general objective of this research was to quantify phenol and p-cresol emission rates (ERs) from different ground-level area sources (GLASs) in a free-stall dairy during summer and winter seasons using this protocol. Two-week-long sampling campaigns were conducted in a dairy operation in central Texas. Twenty-nine air samples were collected during winter and 37 samples were collected during summer from six specifically delineated GLASs (barn, loafing pen, lagoon, settling basin, silage pile, and walkway) at the free-stall dairy. Thirteen VOCs were identified during the sampling period and the GC was calibrated for phenol and p-cresol, the primary odorous VOCs identified. The overall calculated ERs for phenol and p-cresol were 2656 +/- 728 and 763 +/- 212 mg hd(-1) day(-1), respectively, during winter. Overall phenol and p-cresol ERs were calculated to be 1183 +/- 361 and 551 +/- 214 mg hd(-1) day(-1), respectively, during summer. In general, overall phenol and p-cresol ERs during winter were about 2.3 and 1.4 times, respectively, higher than those during summer.

Parental help-seeking for behavioural and emotional problems in childhood and adolescence

Previous publications from the Dunedin Multidisciplinary Health and Development Research Unit have reported the prevalence of DSM-III disorders through its longitudinal examination of a New Zealand birth cohort. The present study describes the help-seeking practices of each sample member's parents for their child's behavioural or emotional problems exhibited in childhood (ages 5-11) or adolescence (ages 12-15). Increased help-seeking for boys was evident in childhood. However, this sex difference was not present at adolescence. There was a decline in the frequency with which medically oriented agencies were contacted between childhood and adolescence, and teachers were found to be the most frequently used source of assistance in adolescence. Although there was a strong association between help-seeking and mental health disorder, approximately half of those with disorder had parents who had not sought help for their child's problems. In addition, family characteristics of low SES, low family social support and poorer maternal mental health predicted help-seeking. The results are discussed in terms of service provision for these age groups, within the present restructuring of the public health system in New Zealand.

Time Perception: Does It Distinguish ADHD and RD Children in a Clinical Sample?

This study used a double-dissociation design to evaluate whether children with ADHD demonstrated specific deficits relative to children with Reading Disorders. Recent theory suggests that ADHD children have deficits in time perception and working memory, whereas RD children have deficits in phonological decoding. The performance of 113 clinic-referred children aged 6-11 was examined using measures of working memory, phonological processing, and time perception. Respondents completed two time production tasks in which they were to judge when 30-s had elapsed, and another in which they were asked to estimate the duration of the Conners' CPT (CCPT). Time Perception and phonological processing variables were submitted to a 2 x 2 ANCOVA (ADHD vs. RD), covarying for age, SES, IQ, and working memory. Children with ADHD were more likely to overestimate the time taken for the CCPT than children without ADHD, but no group differences were found on the 30-s estimation tasks. Children with RD did not display deficits in time estimation, but showed deficits in auditory phonological processing. The lack of interaction effects supported an "etiological subtype" over the "phenocopy" model of ADHD and RD. No group differences were detected using the CCPT. Although our previous studies did not find an order effect for the Conners' CPT in a 1-hr battery, a fatigue effect was evident with a 1.5-hr battery. The implications for Barkley's behavioral inhibition theories (R. Barkley, 1997) are discussed.

Caries prevalence and severity in urban Fijian school children

OBJECTIVES

To determine the prevalence and severity of dental caries in a sample of urban Fijian school children.

DESIGN

Cross-sectional.

SAMPLE AND METHODS

Children aged between 6 and 8 years who attended one of four primary schools in different localities of Suva completed self-report questionnaires and were examined for dental caries.

RESULTS

A total of 704 children (response rate = 72.4%) returned questionnaires and were examined dentally. The prevalence of dental caries in the primary dentition was 87.6% and in the permanent dentition, 46.7%. The mean dfs and mean DFS were 8.43 (SD 7.82) and 2.38 (SD 1.37), respectively. High caries prevalence and severity were associated with infrequent brushing, snacking on sugar-containing foods, having seen a dentist before, and having last visited a dentist because of pain.

CONCLUSIONS

The caries prevalence of the sample was comparable with findings from a national oral health survey conducted in 1985/86, but the caries severity was greater. As in other developing countries, this may be due to an increased availability of refined sugar products without a concurrent rise in oral health awareness. The study findings contribute to the overall picture of Fijian school children's dental health.

Multiple maltreatment, attribution of blame, and adjustment among adolescents

The study examined the predictive utility of blame attributions for maltreatment. Integrating theory and research on blame attribution, it was predicted that self-blame would mediate or moderate internalizing problems, whereas other-blame would mediate or moderate externalizing problems. Mediator and moderator models were tested separately. Adolescents (N = 160, ages 11-17 years) were randomly selected from the open caseload of a child protection agency. Participants made global maltreatment severity ratings for each of physical abuse, psychological abuse, neglect. sexual abuse, and exposure to family violence. Participants also completed the Attribution for Maltreatment Interview (AFMI), a structured clinical interview that assessed self- and perpetrator blame for each type of maltreatment they experienced. The AFMI yielded five subscales: self-blaming cognition, self-blaming affect, self-excusing. perpetrator blame, and perpetrator excusing. Caretaker-reported (Child Behavior Checklist) and self-reported (Youth Self Report) internalizing and externalizing were the adjustment criteria. Controlling for maltreatment severity, the AFMI subscales explained significant variance in self-reported adjustment. Self-blaming affect was the most potent attribution, particularly among females. Attributions mediated maltreatment severity for self-reported adjustment but moderated it for caretaker-reported adjustment. The sophistication and relevance of blame attributions to adjustment are discussed, and implications for research and clinical practice are identified.

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.

Sunburn and sun protection among New Zealand adolescents over a summer weekend

OBJECTIVE

To examine predictors of sunburn and sun protection practices during summer weekends within a sample of NZ adolescents.

METHOD

Phone interviews were conducted with 203 participants aged 12-17 years. Questions were asked about behaviour from 11am to 4pm during the previous weekend.

RESULTS

Less than half of the sample outside during peak radiation hours wore sunscreen and only a quarter wore hats. Sunburn was experienced by 31% of adolescents and was associated with spending longer times outside and use of sunscreen without reapplication. Wearing a sunhat was predicted by being younger and male, while sunscreen use was predicted by being female.

CONCLUSIONS

There is a lack of appropriate sun protection among many NZ adolescents, and correspondingly high rates of sunburn. Possible opportunities to address this are through increasing the efficacy of sunscreen and sun hat use, and creating outdoor environments that support sun avoidance.

Low self-esteem and hopelessness in childhood and suicidal ideation in early adulthood

This study examined the longitudinal relationship between family characteristics in early childhood. self-esteem, hopelessness and thoughts of self-harm in the midchildhood years, and suicidal ideation at ages 18 and 21. Path analysis was used to establish separate models for boys and girls. The results suggested different pathways to later suicidal ideation for boys and girls. For boys, suicidal ideation seemed to have stronger roots in childhood, with significant paths from low self-esteem and hopelessness to early thoughts of self-harm and thence to later ideation. For girls, self-esteem had a small but significant direct effect on later suicidal ideation. The findings provide support for the idea that individual characteristics such as feelings of hopelessness and low self-esteem act as "generative mechanisms," linking early childhood family characteristics to suicidal ideation in early adulthood.

Sun protection practices, knowledge and attitudes to tans among New Zealand adolescents, 1991-1997

AIMS

To examine change in the self-reported sun protection, knowledge and attitudes to tans amongst fourth form students from 1991 to 1997.

METHODS

Questionnaires were mailed to 20 New Zealand secondary schools, where 20 students were randomly selected to participate in each school.

RESULTS

The proportions of adolescents who reported getting sunburnt over summer, and sunbathing for the purpose of tanning increased significantly from 1991 to 1997, while there were decreases in the proportions who reported getting a suntan, wearing clothing for sun protection and having heard of melanoma. There was also some evidence of a decrease in the attribution of positive qualities to a tan.

CONCLUSIONS

Some positive changes in attitudes to tanning among New Zealand adolescents were present over the 1991-1997 period. Although these changes are promising there was little change in utilisation of sun protection measures, in fact, there was evidence that this had worsened.

Effectiveness and economic evaluation of a nurse delivered home exercise programme to prevent falls. 2: Controlled trial in multiple centres

OBJECTIVES

To assess the effectiveness of trained nurses based in general practices individually prescribing a home exercise programme to reduce falls and injuries in elderly people and to estimate the cost effectiveness of the programme.

DESIGN

Controlled trial with one year's follow up.

SETTING

32 general practices in seven southern New Zealand centres.

PARTICIPANTS

450 women and men aged 80 years and older.

INTERVENTION

330 participants received the exercise programme (exercise centres) and 120 received usual care (control centres); 87% (371 of 426) completed the trial.

MAIN OUTCOME MEASURES

Number of falls, number of injuries resulting from falls, costs of implementing the programme, and hospital costs as a result of falls.

RESULTS

Falls were reduced by 30% in the exercise centres (incidence rate ratio 0.70, 95% confidence interval 0.59 to 0.84). The programme was equally effective in men and women. The programme cost $NZ418 (121 pound sterling) (at 1998 prices) per person to deliver for one year or $NZ1519 (441 pound sterling) per fall prevented. Fewer participants had falls resulting in injuries, but there was no difference in the number who had serious injuries and no difference in hospital costs resulting from falls in exercise centres compared with control centres.

CONCLUSIONS

An individually tailored exercise programme, delivered by trained nurses from within general practices, was effective in reducing falls in three different centres. This strategy should be combined with other successful interventions to form part of home programmes to prevent falls in elderly people.

Impact of childhood cancer on the mental health of parents

BACKGROUND

When a child is diagnosed with cancer, the family experiences great stress and disruption to daily life. As part of a national study in New Zealand, we evaluated the mental health of mothers and fathers of children with cancer, making comparisons to parents of children from the general population.

PROCEDURE

This was a cross-sectional study. All children diagnosed with cancer at ages 0-14 years in New Zealand during a defined period were ascertained from the national cancer registry and other databases. The population-based comparison children were selected using national birth records. Parents from both groups completed self-administered questionnaires containing the General Health Questionnaire (GHQ-12) and other measures. The analyses included 218 mothers and 179 fathers of children with cancer, and 266 mothers and 224 fathers of children in the comparison group. Multivariate regression was used to adjust for demographic and socioeconomic characteristics, life events, and social support.

RESULTS

Mothers and fathers of children with cancer had poorer GHQ-12 and mood rating scores than those of controls. The adjusted difference in the mean total GHQ-12 score (comparing mothers of children with cancer to mothers of controls) was 2.2 (95% confidence interval 1.3-3.2). The 12 items of the GHQ were each scored 0-3, and the total score was the sum, so 2 points is a small difference. For fathers the difference was 1.5 (95% confidence interval 0.6-2.4). Some subgroups of cancer group parents had poorer emotional health scores than others, including those with poor social support and no paid employment and also those who were bereaved.

CONCLUSIONS

We found statistically significant but small differences between the mental health of parents of children with cancer and controls. The small differences suggest that as a group the parents of children with cancer are relatively resilient.

Dishabituation processes in height fear and dental fear: an indirect test of the non-associative model of fear acquisition

The fear dishabituation hypothesis described in the non-associative model of fear acquisition was tested in a longitudinal birth cohort study. Results were consistent with height fear and phobia dishabituation. That is, 're-emergence' of a fear of heights occurred between age 11 and 18 years among individuals who reported higher levels of non-specific stress at age 15. Interestingly, there was no evidence for dental fear dishabituation--a finding consistent with the non-associative model of fear acquisition. Strengths and weaknesses of the study were considered and the results discussed in relation to laboratory-based findings on (dis)habituation.

A longitudinal study of cannabis use and mental health from adolescence to early adulthood

AIMS

To examine the longitudinal association between cannabis use and mental health.

DESIGN

Information concerning cannabis use and mental health from 15 to 21 years was available for a large sample of individuals as part of a longitudinal study from childhood to adulthood.

PARTICIPANTS

Participants were enrolled in the Dunedin Multidisciplinary Health and Development Study, a research programme on the health, development and behaviour of a large group of New Zealanders born between 1 April 1972 and 31 March 1973.

MEASUREMENTS

Cannabis use and identification of mental disorder was based upon self-report as part of a general assessment of mental health using a standard diagnostic interview. Daily smoking and alcohol use at age 15 were assessed by self-report. Indices of family socio-economic status, family climate and parent-child interaction were formed using information gathered from parent report and behavioural observations over early childhood. Childhood behaviour problems were assessed by parent and teacher report. Attachment to parents was assessed in adolescence.

FINDINGS

Cross-sectional associations between cannabis use and mental disorder were significant at all three ages. Both outcome variables shared similar pathways of low socio-economic status and history of behaviour problems in childhood, and low parental attachment in adolescence. Mental disorder at age 15 led to a small but significantly elevated risk of cannabis use at age 18; by contrast, cannabis use at age 18 elevated the risk of mental disorder at age 21. The latter association reflected the extent to which cannabis dependence and other externalizing disorders at age 21 were predicted by earlier level of involvement with cannabis.

CONCLUSIONS

The findings suggest that the primary causal direction leads from mental disorder to cannabis use among adolescents and the reverse in early adulthood. Both alcohol use and cigarette smoking had independent associations with later mental health disorder.

Phosphorylation of the flagellar regulatory protein FlrC is necessary for Vibrio cholerae motility and enhanced colonization

The human pathogen Vibrio cholerae specifically expresses virulence factors within the host, including cholera toxin (CT) and the toxin co-regulated pilus (TCP), which allow it to colonize the intestine and cause disease. V. cholerae is a highly motile organism by virtue of a polar flagellum, and motility has been inferred to be an important aspect of virulence, yet the exact role of motility in pathogenesis has remained undefined. The two-component regulatory system FlrB/FlrC is required for polar flagellar synthesis; FlrC is a sigma54-dependent transcriptional activator. We demonstrate that the transcriptional activity of FlrC affects both motility and colonization of V. cholerae. In a purified in vitro reaction, FlrB transfers phosphate to the wild-type FlrC protein, but not to a mutant form in which the aspartate residue at amino acid position 54 has been changed to alanine (D54A), consistent with this being the site of phosphorylation of FlrC. The wild-type FlrC protein, but not the D54A protein, activates sigma54-dependent transcription in a heterologous system, demonstrating that phospho-FlrC is the transcriptionally active form. A V. cholerae strain containing a chromosomal flrCD54A allele did not synthesize a flagellum and had no detectable levels of transcription of the critical sigma54-dependent flagellin gene flaA. The V. cholerae flrCD54A mutant strain was also defective in its ability to colonize the infant mouse small intestine, approximately 50-fold worse than an isogenic wild-type strain. Another mutation of FlrC (methionine 114 to isoleucine; M114I) confers constitutive transcriptional activity in the absence of phosphorylation, but a V. cholerae flrCM114I mutant strain, although flagellated and motile, was also defective in its ability to colonize. The strains carrying D54A or M114I mutant FlrC proteins expressed normal levels of CT and TCP under in vitro inducing conditions. Our results show that FlrC 'locked' into either an inactive (D54A) or an active (M114I) state results in colonization defects, thereby demonstrating a requirement for modulation of FlrC activity during V. cholerae pathogenesis. Thus, the sigma54-dependent transcriptional activity of the flagellar regulatory protein FlrC contributes not only to motility, but also to colonization of V. cholerae.

Tobacco smoking among fourth form school students in Wellington, New Zealand, 1991-97

OBJECTIVE

To investigate trends in smoking and associated demographic factors among fourth form (14-15 years) school students.

METHOD

In 1991, all 35 secondary schools in Wellington, New Zealand, were invited to participate; 15 took part. Smoking behaviours were assessed biennially by self-report. Trends were examined among 5,834 students, using multilevel regression.

RESULTS

When adjusted for sex, ethnicity and their interaction, the baseline (1991) prevalence of smoking within the past month was 18% (95% CI 10-29) rising to 28% (95% CI 15-46) in 1997. The comparable baseline prevalence of daily smoking was 8% (95% CI 3-21) rising to 15% (95% CI 4-40) in 1997. Smoking was more common among girls than boys and most common among Maori girls, for whom the adjusted odds of current and daily smoking were, respectively, 3.40 times (95% CI 2.56-4.52) and 5.00 times (95% CI 3.64-6.87) those of Europeans. School socio-economic status and sex composition added to the explanatory power of the model for daily smoking, but had negligible effect on the odds ratios for sex and ethnic group.

CONCLUSIONS AND IMPLICATIONS

The suggested rise in the prevalence of smoking has implications for future adult smoking rates and health costs. Under-representation of socio-economically disadvantaged schools may have produced conservative estimates. The increased odds of smoking among girls and Maori confirm the need to develop interventions appropriate for these groups.

Proliferation, differentiation and apoptosis in villous trophoblast at 13-41 weeks of gestation (including observations on annulate lamellae and nuclear pore complexes)

Ultrastructural, immunochemical, fluorescence and stereological studies were undertaken on human villous trophoblast from 13 weeks of gestation to term. The aim was to describe and quantify morphological changes during proliferation, differentiation and apoptosis in cytotrophoblast and syncytial regions of non-aggregated and aggregated nuclei. Numbers of trophoblast nuclei increased continuously from 13 weeks. In term placentae, intrasyncytial differentiation was characterized ultrastructurally by gradual decreases in nuclear size and packing density accompanied by nucleolar regression, and increasing heterochromatinization, envelope convolution and packing density of nuclear pore complexes. In densely packed areas, nuclear profiles resembled interlocking jigsaw pieces. Occasionally, these 'pre-apoptotic' nuclei were associated with annulate lamellae. Rarely, nuclear changes terminated in apoptosis with a characteristic pattern of condensed peripheral chromatin, a central island of euchromatin, no nucleoli and no discernible nuclear pores. Apoptotic nuclei were seen singly and within dense nuclear aggregations. Similar spatial patterns of nuclei and chromatin were seen in propidium iodide-stained sections at 13-41 weeks. Whilst the relative incidence of intensely fluorescent nuclei remained constant, absolute numbers increased linearly during gestation and correlated positively with the volume of syncytial knots. Nuclei labelled for DNA fragmentation occurred very infrequently and were also found in nuclear clusters as well as singly. We suggest that nuclear differentiation in syncytium has two phases: on entering syncytium, nuclei become committed to a long programmed pre-apoptotic phase which leads to a short apoptotic execution phase. We propose further that clustered nuclei (pre-apoptotic and apoptotic) in syncytial knots probably represent the extrusion component of normal continuous epithelial turnover.

Parent reported preschool attention deficit hyperactivity: measurement and validity

This is a two stage community study of 320 preschool children aged between two and a half to five years. An Attention Deficit Hyperactivity Scale (ADH-P) was constructed. A first stage sample was screened by asking parents to fill in the ADH-P and the Behaviour Check List (BCL) for behaviour problems; 116 children were included in the second stage. Reliability of the ADH-P was tested and found to be satisfactory. Its validity was also supported by teacher's report and clinical observation. Based on the parent report, the children were divided into four groups: pure hyperactive, pure behaviour problem, mixed and no problem groups. External correlates and psychopathology were examined among them. The mixed group had more symptoms, poor maternal mental health, high social adversities, poor prosocial behaviour and high help seeking. Whilst significant associations were also present between these correlates and pure behaviour problems, the situation was substantially worse when hyperactivity co-existed with behaviour problems.

The horizontal equity of health care in New Zealand

OBJECTIVE

Given that 'equal access for equal need' is a clearly articulated goal of the New Zealand public health system, this study is an attempt to determine if access to public health care services in New Zealand is, for people of equal health need, independent of income.

METHOD

Information on health status, income and health service utilisation for just over 6,000 New Zealanders was obtained from the national Household Health Survey 1992-93. Using standardised expenditure concentration curves and a concentration index, the distribution of health service use by individuals in different income groups, as a proxy for access, was illustrated and quantified.

RESULTS

The results suggest either appropriate or slightly excess use of services by the poor given their estimated health need. Due to analytical problems caused by data deficiencies, these results must be regarded as tentative.

CONCLUSION

For the period under study, no evidence was found to indicate significant access barriers to publicly funded health care for people on different incomes. This study has served to demonstrate one approach to measuring inequality and analysing the relationship between inequality and inequity. Given the reforms to the health sector since 1993, ongoing monitoring of equity of access to health care services is essential.

IMPLICATIONS

Given the income-related disparities in health that do exist, the public health community should endeavour to develop techniques to monitor the delivery of publicly funded health care to ensure that further inequity is not borne by the poor.

Is mental health in childhood a major predictor of smoking in adolescence?

AIMS

To test an extended version of Pomerleau's (1997) hypothesis that children with mental health problems are at higher risk of smoking in preadolescence and adolescence.

DESIGN

Information concerning mental health from 5 to 13 years, smoking at ages 11 and 15, and family disadvantage at age 7 was available for 773 children enrolled in a longitudinal study of children and adolescents.

PARTICIPANTS

Participants were enrolled into the Dunedin Multidisciplinary Health and Development Study, which is a longitudinal investigation of the health, development and behaviour of a large group of New Zealand children born between 1 April 1972 and 31 March 1973.

MEASUREMENTS

Assessment of mental health problems in childhood was based upon parent and teacher reports of behavioural and emotional problems. In pre-adolescence, mental health was assessed by self, parent and teacher report. Smoking was assessed by self-report.

FINDINGS

None of the potential risk factors of gender, childhood disadvantage or childhood mental health problems predicted onset of smoking in pre-adolescence. Daily smoking at age 15 was best predicted by smoking in preadolescence, being female and experiencing childhood disadvantage. Pre-adolescent mental health was only weakly predictive of later smoking and this association appeared to be confounded with background disadvantage.

CONCLUSIONS

We found little support for the extension of Pomerleau's (1997) hypothesis to childhood mental health. Our findings also run counter to recent suggestions for targeting smoking prevention at groups of children with mental health disorders.

Sun protection behaviours and the predictors of sunburn in young children

OBJECTIVE

To explore the use of sun protection behaviours and the experience of sunburn in a sample of parents and their children in New Zealand.

METHODOLOGY

Information was collected from 887 parents using postal questionnaires at the beginning of and during the summer.

RESULTS

Thirty per cent of the parents believed their child looked healthier with a suntan, and 40% intended to let their child get a suntan during the summer. Predictors of intention to tan included level of parental education, the child's age, the child's sensitivity to burning and experience of sunburn in the parent. At the end of the summer period, 29% of the children were reported as being sunburned. Predictors of sunburn in the child were the age of the child, experience of sunburn in the parent and use of sunscreen SPF15+ by the parent.

CONCLUSION

Despite intense media coverage of the dangers of overexposure to the sun, it is clear that a significant proportion of children are still getting sunburned.

Caregiving and well-being in a sample of women in midlife

A survey of 742 women in midlife found that 12% were involved in the care of another person with a chronic health disorder. Of note was the diversity of circumstances that led to the women becoming caregivers. Further, about a third of the carers were supporting more than one person. Carers did not differ on measures of depression or subjective health ratings from persons not involved in care. Burden scores were predicted by co-residence, low satisfaction with social support, and poorer health ratings on the part of the carers but not by the relationship between the person cared for and the carer.

Are young adults checking their skin for melanoma?

This study examined the prevalence and predictors of self screening for melanoma in a large sample of young New Zealanders. A self-report questionnaire was administered to a sample of 909, 21-year-olds to investigate if young adults check their skin for changes in lesions which could be melanoma, and to identify the factors which influence this behaviour and any subsequent help seeking. Fifty-three per cent reported checking their skin in the past year, with 20% noticing a change in a mole or freckle. Forty-five per cent of those who noticed a change sought medical advice. The most common reason for not seeking advice was cost. Women were more likely that men to have checked their skin, to have noticed a change and to have sought medical advice. In addition to gender, tendency to self check was also associated with knowledge of melanoma and perceived risk of melanoma. These results are discussed in light of the current debate regarding skin cancer screening. This study fills a gap in the literature regarding self screening for melanoma in young adults and identifies ways in which future prevention campaigns might be modified to address the concerns of this age group.

Children's understanding of sun protection behaviours: a comparative analysis

OBJECTIVE

To investigate awareness of sun protection behaviours in a sample of primary school children in New Zealand.

METHODOLOGY

Information was collected from 824 primary school children in New Zealand using a drawing and writing technique.

RESULTS

The data revealed a bias towards sunscreen as a method of sun protection compared with other methods such as clothing and the use of shade. Comparisons between results obtained from children resident in Australia and England indicated a greater awareness of sun protection methods amongst the children from Australia and New Zealand compared with those children living in England.

CONCLUSIONS

Children as young as 5 and 6 can describe the consequences of overexposure to the sun, and can illustrate methods of sun protection. Sunscreen is seen as the main method of sun protection.

Physical assault in New Zealand: the experience of 21 year old men and women in a community sample

AIM

To obtain epidemiological information on physical assault in a high risk group of New Zealanders.

METHOD

Rates of physical assault in the preceding twelve months were ascertained by interview in a cohort of 21 year old, Dunedin-born men (n = 482) and women (n = 462).

RESULTS

Forty-five percent of the men and one quarter of the women reported at least one physical assault, either completed, attempted or threatened. A small proportion of these received medical treatment. Most serious assaults were by a perpetrator who was thought to have been drinking alcohol. Most assaults on men were by strangers but partners carried out more assaults against women, especially those receiving medical treatment. One quarter of all assaults on women were by other women, compared to 15% of the assaults on men. Differences between patterns of assaults on women and on men are discussed.

CONCLUSION

It is important for doctors to be aware of the widespread occurrence of interpersonal violence in New Zealand and its underreporting.

Development of depression from preadolescence to young adulthood: emerging gender differences in a 10-year longitudinal study

The authors investigated the emergence of gender differences in clinical depression and the overall development of depression from preadolescence to young adulthood among members of a complete birth cohort using a prospective longitudinal approach with structured diagnostic interviews administered 5 times over the course of 10 years. Small gender differences in depression (females greater than males) first began to emerge between the ages of 13 and 15. However, the greatest increase in this gender difference occurred between ages 15 and 18. Depression rates and accompanying gender differences for a university student subsample were no different than for a nonuniversity subsample. There was no gender difference for depression recurrence or for depression symptom severity. The peak increase in both overall rates of depression and new cases of depression occurred between the ages of 15 and 18. Results suggest that middle-to-late adolescence (ages 15-18) may be a critical time for studying vulnerability to depression because of the higher depression rates and the greater risk for depression onset and dramatic increase in gender differences in depression during this period.

Development of depression from preadolescence to young adulthood: emerging gender differences in a 10-year longitudinal study

The authors investigated the emergence of gender differences in clinical depression and the overall development of depression from preadolescence to young adulthood among members of a complete birth cohort using a prospective longitudinal approach with structured diagnostic interviews administered 5 times over the course of 10 years. Small gender differences in depression (females greater than males) first began to emerge between the ages of 13 and 15. However, the greatest increase in this gender difference occurred between ages 15 and 18. Depression rates and accompanying gender differences for a university student subsample were no different than for a nonuniversity subsample. There was no gender difference for depression recurrence or for depression symptom severity. The peak increase in both overall rates of depression and new cases of depression occurred between the ages of 15 and 18. Results suggest that middle-to-late adolescence (ages 15-18) may be a critical time for studying vulnerability to depression because of the higher depression rates and the greater risk for depression onset and dramatic increase in gender differences in depression during this period.

Level of education, age of bearing children and mental health of women

The present study examined the longitudinal relationship between women's mental health and both their level of education and age at which they had their first child. The women were divided into four groups depending on whether or not they had further education after leaving school and whether or not they had a baby before the age of 21. Longitudinal data collected over a 19-year period from this group of women suggested that psychological morbidity was relatively stable across this time span. Women who left school without proceeding to further education and those who became mothers before the age of 21 had higher psychological symptom scores than the other groups throughout this period. These two factors were associated with poorer mental health in an additive fashion. The women were also more likely to have separated from the father of their child and continued to be economically disadvantaged into mid-life.

Sunburn and sun protection among young children

OBJECTIVE

To examine the extent of sun exposure, sun protection and experience of sunburn among young New Zealand children on summer weekends.

METHODS

In a telephone survey of 1243 respondents, those with children in the household were asked about sun exposure and protection for the youngest child in the family. Information was obtained for 285 children aged from infancy to 10 years.

RESULTS

Over 90% of the children were reported to be outside on the preceding Saturday and/or Sunday; 7% of those outside experienced some degree of sunburn. The worst burning was on the face, head, neck or ears. On either day about half the children were wearing sunscreen and 60% were wearing a hat. Parental use of sun protection was the strongest predictor of sun protection among the children.

CONCLUSIONS

While reports of sun protection among young children were encouraging, many children in the community are still at high risk of sunburn. Efforts to promote sun protection as a family responsibility may reduce the experience of burning among the young.

Sun behaviour and perceptions of risk for melanoma among 21-year-old New Zealanders

This study investigated perceived risk of melanoma, sunscreen use and frequency of sunburn in a large sample of young New Zealanders. A self-report questionnaire was administered to a sample of 909 21-year-olds to survey their perception of how sun behaviours affect their risk of getting melanoma, how often they get sunburn, how often they use sunscreen and what factors would get them to use sunscreen more often. Knowledge of melanoma was high, but myths concerning 'safe tanning' persisted. Many young adults believed that sunbathing regularly using a sunscreen and obtaining a good base tan from gradual sun exposure decreased their risk of getting melanoma. They were unsure about the use of artificial sun beds and if their use would increase or decrease their risk. Males and females differed significantly on many aspects of their sun behaviour. Most used sunscreen only 'sometimes' and its use was linked to knowledge of melanoma and perceptions of risk. The best way to modify the sun behaviour of young adults is to target both their knowledge of melanoma risk factors and their perceptions of risk.

Psychometric properties of the Centre for Epidemiologic Studies Depression Scale (CES-D) in a sample of women in middle life

The Centre for Epidemiologic Studies Depression Scale (CES-D) was completed by 675 women taking part in a longitudinal investigation of health-related issues. The data were submitted to confirmatory factor analysis using LISREL 7 and a 4-factor model was found to fit the data moderately well. A second-order depression factor was also identified. The results provide support for the construct validity of the total and subscale scores from this measure. The scale was found to have good reliability. Evidence was found that scores on the subscale measuring somatic features of depression may be inflated in women who have experienced a chronic health problem in the past 12 months.

Inattentive and hyperactive behaviors and driving offenses in adolescence

OBJECTIVE

The associations between symptoms of attention-deficit hyperactivity disorder (ADHD), conduct disorder, anxiety, or depression and no disorder in relation to driving offenses were examined in 916 adolescents.

METHOD

Self-report and parent report were used to assess a birth cohort of New Zealand adolescents' mental health status at age 15 years. Adolescents who scored 1.5 SD above the mean on the DSM-III total ADHD symptom scale were identified as reporting significant ADHD symptomatology. Self-report data and official traffic conviction records were used to identify adolescents who had committed driving offenses between ages 15 and 18 years.

RESULTS

ADHD symptomatology and conduct disorder were strongly associated with driving offenses. ADHD symptomatology in females was significantly associated with driving offenses and more traffic crashes compared with other disorder or no disorder.

CONCLUSIONS

Adolescents with a history of ADHD and conduct problems are significantly more likely than their peers to commit traffic offenses. Research in ADHD and risky driving should include female adolescents, as those with attentional difficulties are at a high risk for being involved in traffic crashes than females who do not experience attentional difficulties.

A comparison of time trade-off and quality of life measures in patients with advanced cancer

Quality of life (QOL) measures are now accepted as indicators of efficacy in the palliative treatment of cancer. Utility measures may also provide valuable information in this area yet they have rarely been applied. To assess the concordance of QOL and utility scales, 93 patients with advanced, symptomatic cancer completed two QOL instruments, the Spitzer Quality of Life Index (QLI) and Spitzer Uniscale, and a time-trade off (TTO) question reflecting the utility of their health states. The scales were self-administered. All patients completed the QLI and Uniscale but only 37% of participants were prepared to trade time. The remainder comprised 39% who felt too well to trade time and 24% who did not wish to consider trading time at all. Those prepared to trade time had significantly worse scores on both QLI and Uniscale instruments than those who felt too well to trade. However the correlation between time traded and QLI and Uniscale scores was poor. We conclude that the TTO question used in this study, while not strongly related to QOL, provides a measure of the patient's attitude to their health state. This may explain why patients differ in their attitude to quantity vs. quality of life.

The (in)stability of adolescent fears

This study examined change in different types of fear in a longitudinal study of a birth cohort from age 13-15 yr. When viewed cross-sectionally there were few differences in the frequency and content of fears reported at these ages with the exception of an increase in social fears at age 15. When viewed longitudinally, however, few adolescents who reported fears at age 13 continued to report fears 2 yr later. Implications for developmental theories of fear and phobia are discussed.

Use of the new media for medical education

The use of an advanced communication network for education has been an integral part of practice at the Mayo Clinic since 1986. The network has been used for patient care, research coordination and administrative support, as well as for educational programming. In 1994, 2655 hours were broadcast by satellite. There were 42,292 participants, representing a total of 47,364 contact hours. Over half of this activity was educational. In using the satellite system, a number of background support systems have been found to be essential to effective communication. First, highly trained technical staff are required to support the communication system. Second, presenters require formal training in adapting audiovisual materials, such as slides and transparencies, to broadcast media. Third, as use of the system has grown, scheduling and prioritizing among the many users has become an increasingly time-consuming and challenging task.

The New Zealand Rugby Injury and Performance Project: alcohol use patterns within a cohort of rugby players

Although heavy drinking has traditionally been associated with rugby, the drinking patterns of New Zealand rugby players have not been examined. Three hundred and forty-eight rugby players (257 males and 91 females), completed the Alcohol Use Disorders Identification Test (AUDIT) at the beginning of the 1993 rugby season. The mean AUDIT scores were 11.2 (SD = 5.1) for the males and 8.7 (4.1) for the females: a cut-off of 8.0 has been recommended by the developers of the instrument for identifying alcohol use disorders. The consumption of large quantities of alcohol, and a high frequency of heavy drinking sessions were the norm for this group. Sixty-one per cent of males and 38% of females consumed six or more drinks in a session at least weekly: typically, men drank 10 or more drinks in a session and women 5-6 drinks. The patterns of drinking exhibited by the cohort give cause for concern regarding the health risks associated with such behaviour.

Personality traits are differentially linked to mental disorders: a multitrait-multidiagnosis study of an adolescent birth cohort

The authors assessed the relation between personality and mental disorder in a representative birth cohort of 897 men and women. Personality was assessed at age 18 with the Multidimensional Personality Questionnaire (MPQ; A. Tellegen, 1982), and 4 types of mental disorder (affective, anxiety, substance dependence, and conduct disorder) were assessed at ages 15, 18 and 21, using age-appropriate standardized diagnostic interviews. All disorder groups had MPQ profiles that were very different from those of controls. When comorbid cases were excluded, fewer significant differences between diagnosed cases and controls remained. Relations between personality and mental disorder were not affected by the measurement of disorder as continuous versus discrete, gender, or the age at which disorder was diagnosed. Relations between personality and mental disorders appear to be robust, and individual personality differences may be particularly relevant to understanding the most severe (comorbid) expressions of psychopathology.

Help-seeking for behavior problems by parents of preschool children: a community study

OBJECTIVE

To identify barriers to seeking help for preschool behavior problems and understand the pattern of service utilization.

METHOD

Altogether, 320 preschool children from eight preschool centers were studied using a two-stage design. After the initial screening, a more detailed assessment was carried out in the second stage involving semistructured interviews with parents and children. Parents also completed a service utilization questionnaire during the first stage and General Health Questionnaire, Family Assessment Device, and life events questions during the second stage.

RESULTS

Only 19% of those with preschool behavior disorder crossed all the filters in reaching for help. The most common perceived barriers to help-seeking were that problems would get better by themselves or that parents should be strong enough to handle them. The major blocks to help-seeking were at two levels, in parents recognizing the presence of a problem and in overcoming the perceived barriers by the parents. Parents sought help from the informal agencies more often than from the formal. Help was sought significantly less often by those who had parental separation, low income, or multiple adversities, all of which were known to be significantly associated with behavior disorder.

CONCLUSION

These findings indicate the need to educate and influence the parents' attitude to help-seeking, target those at risk to develop behavior disorder, and develop better consultation-liaison service with the informal agencies.

Adolescents' promotion of nonsmoking and smoking

Previous studies of the influence of friends on adolescent smoking have adopted the approach of asking adolescents about their friends. However, studies in which the friends were also approached have shown that adolescents' reports of friends behavior were not accurate (more closely resembled their own behavior). In order to gauge the level of active social influence among adolescents we asked 14-15 year old students what they did to influence others not to smoke or to smoke. Across two surveys, a quarter of the Form 4 students were promoting antismoking messages or activities and 3% were promoting smoking by encouraging or forcing friends, siblings and acquaintances to smoke. Relatively more positive beliefs about smoking identified those students who actively promoted smoking whereas some positive beliefs about the adverse effects of cigarette advertising tended to identify those who were actively antismoking. Use of this approach to examine the issue of social influence provided information about the antismoking activities which students conducted, and could be used to further examine which messages students do not believe or do not use. For example, students believed that smoking reduces fitness but did not promote this message to others, and the reasons for such disparity need to be investigated and should be addressed in the content of prevention programs.