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Biomedical subjects

D M Fergusson

Publications and source records attributed to D M Fergusson.

At least 19 recordsLinked to original sources

Attention deficit and reading achievement.

A model for estimating possible reciprocal relationships between attention deficit and reading achievement is proposed. This model is fitted to data for a birth cohort of New Zealand children studied at 10 and 12 years on measures of attention deficit and reading achievement. Model estimates suggest that at the age of 12 years the predominant direction of causality is that attention deficits influence reading achievement and there is no evidence to suggest that reading achievement influenced attention deficit levels. The implications of these findings are discussed.

Achievement

Family change, parental discord and early offending.

The relationship between exposure to family change, exposure to parental discord during the period from birth to 10 years and risks of offending by the age of 13 years was studied in a birth cohort of New Zealand children. This analysis showed that while exposure to parental discord during middle and early childhood led to increased risks of early offending, exposure to family change in the absence of parental discord did not lead to increased risks of offending. The results also suggested that children with a history of early conduct problems were particularly susceptible to parental discord but that the effects of discord did not vary with the child's gender. These results persisted when errors of measurement in the reporting of offending were taken into account using latent class methods.

Adolescent

Smoking during pregnancy and its effects on child cognitive ability from the ages of 8 to 12 years.

Maternal smoking during pregnancy and subsequent child cognitive development and ability were examined in a birth cohort of New Zealand children studied to the age of 12 years. Analysis at a bivariate level showed that children whose mothers smoked during pregnancy scored significantly lower on standardised tests of intelligence, reading and mathematical ability than children whose mothers did not smoke. However, after adjustment for confounding covariates, the results showed no detectable relationship between smoking during pregnancy and child cognitive ability. These results suggest that children whose mothers smoked during pregnancy fared worse on tests of cognitive ability not because of possible causal effects of smoking, but rather because these children tended to come from families which provided a relatively disadvantaged home environment.

Child

Confirmatory factor models of attention deficit and conduct disorder.

The paper presents four alternative confirmatory factor models to represent the structure of measures of attention deficit and conduct disorder obtained from multiple sources. These models range in complexity from a simple one-factor model with no method effects to a two-factor model with method effects. These models were fitted to data gathered on maternal, teacher and self-report of attention deficit and conduct disorder for a sample of New Zealand children studied at ages 9 and 10 years. The analysis strongly suggests that the best representation of the data was a two-factor model in which there were distinct factors of attention deficit and conduct disorder with these factors being highly correlated (r = 0.87-0.88). It is suggested that the most suitable clinical nomenclature may be to describe conduct disorder and attention deficit generically as externalizing disorders, subscripting this classification with clauses which describe the relative contributions of conduct disorder and attention deficit. The implications of this finding for the measurement, classification and explanation of conduct disorder and attention deficit disorder are discussed.

Attention Deficit Disorder with Hyperactivity

A model of stability and change in minor psychiatric symptoms: results from three longitudinal studies.

A statistical model designed to estimate the contributions of stable and changing symptomatology to levels of minor psychiatric symptoms is developed. This model is fitted to data obtained from three longitudinal studies. These studies involved subjects from Canberra (Australia), Christchurch (New Zealand) and Groningen (Holland). Data from all three data sets were shown to fit the proposed model adequately. However, there were systematic differences in the findings of the study. The findings from the Canberra and Groningen studies suggested that a large amount (50-75%) of the variance in symptom levels could be attributed to between subject difference in stable levels of symptomatology. In contrast the Christchurch study suggested a smaller contribution of stable symptomatology. These differences may be explained by the nature of the samples studied. All three studies showed evidence of strong correlations (0.79-0.94) between stable levels of symptomatology and the measure of trait neuroticism. It is concluded on the basis of this evidence that the neuroticism may be little more than a way of measuring the subject's characteristic level of minor psychiatric symptoms. The model also made it possible to secure estimates of the extent to which measures of neuroticism were contaminated by short-term mental state. Estimates of contamination effects varied between studies. For the Canberra data contamination was negligible, for the Groningen data mild contamination effects were present but for the Christchurch data contamination was larger. These differences may be explained by differences in the nature of the samples studied.

Adaptation, Psychological

Secondary enuresis in a birth cohort of New Zealand children.

The development of secondary enuresis was examined in a birth cohort of New Zealand children studied to the age of 10 years. By this age, 7.9% of children had developed secondary enuresis. Analysis suggested two risk factors were involved in secondary enuresis. First, children who were late to attain nocturnal bladder control had significantly higher risks of secondary enuresis than children who attained early nocturnal bladder control. Secondly, the child's level of exposure to adverse life events was associated with the onset of secondary enuresis. Children who attained bladder control after 5 years were 3.39 (1.76-6.56) times more likely to develop secondary enuresis than those who attained bladder control before the age of 3 years (P less than 0.001); children who were exposed to four or more life events in a given year were 2.56 (1.18-5.50) times more likely to develop secondary enuresis in that year (P less than 0.05). These results suggest that the rate at which the child acquires primary bladder control acts as a vulnerability factor which determines the child's susceptibility to developing secondary enuresis when exposed to stress.

Child

Vulnerability to childhood problems and family social background.

The relationship between family social background and risks of problems in the areas of health, education, behaviour and offending was examined in a birth cohort of New Zealand children studied to the age of 11 years. The analysis showed the presence of small consistent correlations between family social background and individual outcomes on a range of childhood measures. These correlations ranged from 0.12 to 0.31 with a median value of 0.18. The association between family social background and childhood outcomes was modelled using LISREL modelling methods which assumed that this association was mediated by common non-observed vulnerability processes. This analysis suggested that while variations in family social background act as relatively weak determinants of specific problem outcomes, these factors had a relatively strong influence on the child's generalized vulnerability to a wide range of childhood problems. The implications of these results for research into social background and childhood are discussed.

Achievement

Early solid feeding and recurrent childhood eczema: a 10-year longitudinal study.

The relationship between early solid feeding practices and risks of recurrent or chronic eczema in childhood was examined in a birth cohort of New Zealand children studied to the age of 10. By the age of 10 years, 7.5% of children had chronic or recurrent eczema. There were clear and consistent associations between the diversity of the child's diet during the first 4 months and risks of eczema. Even when due allowance was made for a range of confounding factors--including parental atopic illness, atopic illness in siblings, the child's early milk diet, and family social background--children exposed to four or more different types of solid food before 4 months had risks of recurrent or chronic eczema that were 2.9 times those of children who were not exposed to early solid feeding. It is concluded that early exposure to a diet diverse in potential food antigens may act to predispose susceptible children to recurrent or chronic childhood eczema.

Chronic Disease

Medical insurance and childhood general practitioner contacts.

The relationships between the duration of medical insurance coverage and rates of general practitioner consultations for morbidity were examined for a birth cohort of children studied to ten years. This showed that children from insured families had higher consultation rates even when due allowance was made for known social and economic factors correlated with the ownership of insurance. During the period from birth to five years children who were insured throughout the period made a mean of 19.16 consultations compared to 15.38 for the uninsured (p less than 0.001); during the period from five to ten years the insured made 13.07 contacts compared to 9.38 for the uninsured (p less than 0.001). The net effects of these trends were that children whose families had been insured throughout the ten year study period made a mean of nine more general practitioner consultations by the age of ten years than children from uninsured families. It is concluded that the presence of private medical insurance encourages the development of inequalities in childhood access to health care with children from insured families having greater access to care than children from uninsured families.

Child

Patient perceptions of general practitioner fees.

General practitioner fees were surveyed in a sample of 1033 families with eleven year old children. The median fee paid for a child consultation was $12.00 and for an adult consultation $22.00. The majority of respondents were of the opinion that these fees were too high: over half said this about child fees and over two thirds believed adult fees were too high. Patient estimates of reasonable fees were, on average, $8.00 for a child and $15.00 for an adult. There were clear and consistent dose/response relationships between the fee level charged and the likelihood that the fee would be described as too high. Comparisons of the fees paid by this cohort in 1980 with fees in 1988 indicated that child fees had increased at an average rate of 24% per annum during this period. The implications of these findings for health care delivery are discussed and the possible impact of recent increases in GMS benefits on levels of dissatisfaction with fees are examined.

Adult

The relationships between neuroticism and depressive symptoms.

A structural equation model designed to estimate the reciprocal associations which may exist between mental state and personality trait variables is presented. This model is applied to measures of neuroticism and depression obtained for a sample of over 1000 women studied over a two year period. The fitted model suggests that while measures of neuroticism are contaminated by the effects of short term mental state on the reporting of personality, there is still a fairly substantial relationship between trait neuroticism (corrected for the effects of mental state contamination) and reports of depressive symptoms.

Depression

The Christchurch Child Development Study: a review of epidemiological findings.

The Christchurch Child Development Study is a longitudinal study of a birth cohort of 1265 New Zealand children who have been studied over an 11-year period using data from multiple sources including parental interview, medical records, teacher questionnaires and direct testing of children. The article provides a review of the major lines of epidemiological research examined in the Study. These include: breast feeding and child health; parental smoking and child health; the effects of low level lead exposure; childhood asthma; nocturnal bladder control; the effects of early hospital admission; the distribution of child health services; and the consequences of private medical insurance. In addition a number of general topics (sample attrition, measurement error, individual differences and causal inference) relating to longitudinal designs are discussed briefly. It is concluded that the longitudinal design is a powerful and cost-effective method of gathering data for general paediatric epidemiological purposes but that research in this area would benefit from an increased use of emerging methods of statistical modelling.

Child

Ketotifen in asthma.

Sixty children aged 5-13 years with moderately severe asthma took part in a double-blind, placebo-controlled trial of ketotifen. The design incorporated a 22 week study period, the addition of ketotifen or placebo to the current medication, and a controlled withdrawal of the regular therapy. Children receiving ketotifen showed significantly lower mean numbers of asthma attacks and less absence from school. The addition of ketotifen to existing treatment was associated with marginally significant changes in rates of day and night wheezing. In the second phase of study, additional therapy was withdrawn from both the ketotifen and placebo groups which resulted in a high (percentage) withdrawal. Children receiving ketotifen did not have a significantly lower failure rate than those given placebo.

Asthma

Infant circumcision.

A prospective one year study of a birth cohort of 1262 infants indicates that the rate of infant circumcision has decreased substantially and is now about 25 percent. Most are performed at parental request and for family and traditional reasons rather than medical indications.

Circumcision, Male

Factors associated with ex-nuptial birth.

The paper examines the background to 210 live exnuptial births studied in the first phase of the Christ-church Child Development Study. The results show: 1. That nearly half of the children had been conceived within cohabiting situations. 2. That nearly one in five ex-nuptial children was the result of a planned pregnancy. 3. Maternal reactions to the birth and pregnancy varied with the mother's situation: cohabiting mothers reported considerably less adverse reaction to the birth than did non-cohabiting mothers. 4. Overall, mothers of ex-nuptial children had a fairly sophisticated appreciation of contraceptive methods. 5. One quarter of unplanned ex-nuptial pregnancies were the result of contraceptive failure and three-quarters were the result of contraceptive non-usage. 6. In common with previous findings for nuptial pregnancies, about 35 percent of unplanned ex-nuptial pregnancies were ascribed to a breakdown in the mother's pattern of usage of the contraceptive pill.

Adolescent

Smoking during pregnancy.

The paper examines smoking amongst a sample of 1248 women giving birth to live-born infants. The findings show: 1. That about 26 percent of women smoked throughout pregnancy and a further 8.0 percent smoked at some time during pregnancy. 2. Smoking during pregnancy was realted to the mother's social background: younger mothers, non-European mothers, mothers with no formal educational qualifications, mothers of low socioeconomic background and mothers of ex-nuptial infants tended to smoke more during pregnancy. 3. Smoking was associated with a decrease in birth weight, a greater risk of low birth weight (less than 2500g) infants and a greater risk of spontaneous abortion. There was no statistically significant relationship between smoking during pregnancy and: the risk of complicated labour, time to the onset of neonatal respiration, the use of active resuscitation or the risk of neonatal infection.

Adult