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Biomedical subjects

R J Rona

Publications and source records attributed to R J Rona.

At least 19 recordsLinked to original sources
PubMed1992

A methodology for simulating the impact of DNA-probe services on the outcomes of pregnancies.

For certain single-gene disorders, DNA probes allow individuals to make more informed decisions about family size and the outcomes of pregnancies. They may also have important psychological effects. We present a method of assessing their impact on the outcomes of pregnancy. We conclude that the traditional approach, which focuses solely on the potential of prenatal diagnostic services to reduce affected births, is limited. It neglects the potential of such services to promote an increase in unaffected births by reducing the number of unnecessary terminations.

DNA Probes↗
PubMed1992

DNA probe technology: implications for service planning in Britain.

For certain genetic conditions DNA testing identifies carriers and determines the risk status of foetuses, thus helping parents to make more informed prenatal decisions. Data, collected from three genetic centres in England and Wales from August 1986 to July 1990, are used to describe trends in demand for DNA testing, the impact of DNA tests on carrier risk assessment, and the use of DNA tests in relation to pregnancy outcome. Altogether the data include 23,388 subjects and 681 pregnancies in 8738 families divided into five cohorts by year of entry and referral. The most frequent gene disorders referred to the genetic centres are currently being tested or will soon be tested. For these disorders the initial high level of activity has declined and may have reached steady state. Demand for DNA services is high for cystic fibrosis and Duchenne muscular dystrophy, intermediate for Huntington's disease, and low for adult polycystic kidney disease, phenylketonuria and tuberous sclerosis. Based on these findings we suggest that demand for DNA tests will be high in serious, untreatable and slow progressing conditions with early onset; intermediate for conditions affecting intellect and neurological integrity with later onset; and low for treatable, late-onset conditions, or those for which there is evidence of heterogeneity, and variable penetrance. It would be helpful to assess the extent to which this view of demand is confirmed when the new disorders being DNA tested are considered and for the pattern of activity of DNA testing for some types of cancer. Since no DNA centre could offer a fully comprehensive testing service, it is recommended that a structure is created to audit overall activity, assist in policy formulation, and influence supraregional service organisation, in order that the spread of DNA services be planned as effectively as possible. This structure would facilitate monitoring of the evolution of contract specifications agreed by commissioners and providers on a regional basis.

Adolescent↗
PubMed1992

Trends in body mass index in young adults in England and Scotland from 1973 to 1988.

STUDY OBJECTIVE: The aim was to determine whether the mean body mass index of young adults in England and Scotland had increased during the years 1973 to 1988. DESIGN: The study was an analysis of reported heights and weights for parents of children participating in a mixed longitudinal study of children's growth. SETTING: 20 study areas (16 in England and four in Scotland) were selected by stratified random sampling. SUBJECTS: Subjects were parents of 5229 children who were new entrants to the study in the years 1973-6 and 1982-8. After excluding cases containing missing values on continuous variables, data for 4568 (87%) women (mean age 30 years) and 4029 (77%) men (mean age approximately 32 years) were analyzed. MEASUREMENTS AND MAIN RESULTS: Changes in weight for height over time were determined using body mass index as dependent variable, adjusting for age, social class, family size, and study area. In women, mean body mass index showed an annual increase of 0.10 (95% CI 0.03 to 0.17%) per year of study. Body mass index also increased with increasing age and family size and was greatest for women with husbands in manual occupations. The secular trend in body mass index in women was not explained by changes in the distribution of these variables. The proportion of women with BMI greater than 25 kg/m2 increased over the study period. In men the secular trend in body mass index was not quite significant in this age group [annual increase 0.05% (-0.01 to 0.12%)]. CONCLUSIONS: There has been an increase in the body mass index of young women in England and Scotland over the years 1973 to 1988. This increase was not explained by changes in the age, parity, social class of the subjects sampled. Evidence of a trend in men was not found.

Age Factors↗
PubMed1992

Height and age adjustment for cross sectional studies of lung function in children aged 6-11 years.

BACKGROUND: No standard exists for the adjustment of lung function for height and age in children. Multiple regression should not be used on untransformed data because, for example, forced expiratory volume (FEV1), though normally distributed for height, age, and sex, has increasing standard deviation. A solution to the conflict is proposed. METHODS: Spirometry on representative samples of children aged 6.5 to 11.99 years in primary schools in England. After exclusion of children who did not provide two repeatable blows 910 white English boys and 722 girls had data on FEV1 and height. Means and standard deviations of FEV1 divided by height were plotted to determine whether logarithmic transformation of FEV1 was appropriate. Multiple regression was used to give predicted FEV1 for height and age on the transformed scale; back transformation gave predicted values in litres. Other lung function measures were analysed, and data on inner city children, children from ethnic minority groups, and Scottish children were described. RESULTS: After logarithmic (ln) transformation of FEV1 standard deviation was constant. The ratios of actual and predicted values of FEV1 were normally distributed in boys and girls. From the means and standard deviations of these distributions, and the predicted values, centiles and standard deviation scores can be calculated. CONCLUSION: The method described is valid because the assumption of stable variance for multiple regression was satisfied on the log scale and the variation of ratios of actual to predicted values on the original scale was well described by a normal distribution. The adoption of the method will lead to uniformity and greater ease of comparison of research findings.

Age Factors↗
PubMed1992

Weight-for-height in children aged 4-12 years. A new index compared to the normalized body mass index.

Data from the 1990 survey of the National Study of Health and Growth, comprising 3357 white English boys and 3050 white English girls, were used to construct and evaluate a new index of weight-for-height. Prediction of triceps + subscapular skinfold thickness, using half of the data, led to the index (weight -9)/height3.7, where weight was in kilograms, height in metres. Using the second half of the data the index was shown to have almost as good a correlation with normalized (triceps + subscapular skinfold) as the body mass index (BMI) in children aged 4-12 years. The new weight-for-height index had stable variance from age 4 to 12 years after simple log transformation, unlike the BMI which required transformation via three age-related parameters prior to analysis or centile calculation. Neither index was a good proxy for skinfold measurements for comparison of ethnic groups. From data from inner city areas surveyed in 1989 children of Indian subcontinent origin had substantially lower weight-for-height, but only Gujarati children were thinner than white children, whereas Afro-Caribbean children were slightly heavier for their height, but thinner. Centiles of weight-for-height, and of BMI by age, for ages 4-12 years, were calculated for white English boys and white English girls.

Body Height↗
PubMed1991

Social environment and height: England and Scotland 1987 and 1988.

This study was designed to investigate the social characteristics associated with the height of primary schoolchildren aged from 5 to 11. Data were analysed for 8491 representative sample children measured in England and Scotland in 1987 and 1988 and 3203 inner city children measured in England in 1987. Height was negatively associated with social class but the association was not significant after allowing for biological variables. A negative gradient of height with size of sibship was evident in white children but was less so in Afro-Caribbean and Asian children. The individual associations of 11 different environmental characteristics were examined after allowing for biological factors and size of sibship. Consistent associations with height included a negative gradient of height with increasing latitude and an association of taller stature with increasing maternal age. A social class gradient in height is accounted for by associations with biological factors, particularly the parental heights; environmental attributes are weakly associated with height after allowing for biological factors.

Birth Order↗
PubMed1991

Audit from preschool developmental surveillance of vision, hearing, and language referrals.

Referrals from preschool medical examinations were followed up for two years to assess attendance rate, waiting time for appointment, appropriateness of the referral, the diagnosis and management of the condition. Altogether 184 children were referrals for ophthalmology, 285 for audiology, and 195 for speech therapy. The median waiting time for an appointment was 46 days in ophthalmology, 175 days in audiology, and 83 days in speech therapy. The poorest attendance rate was identified in speech therapy (75%). Approximately 60% of examined children had a justified referral to ophthalmology and 20% had a clear defect. Over half the children in audiology (55%) had an altered impedance or hearing impairment. Of those with a hearing problem kept under review only half improved spontaneously. In speech therapy 80% of those assessed had a language problem. Many health problems were detected for which parents were unaware or did not use the service. Parental awareness alone will not uncover the sizable level of lingual and sensorial problems in inner city areas. This audit identified specific deficiencies in the provision of services and a number of organisational changes are suggested to improve their effectiveness.

Age Factors↗
PubMed1991

Quantifying health aspects of passive smoking in British children aged 5-11 years.

STUDY OBJECTIVE: The aim was to estimate the dose-response relations of height and respiratory symptoms to passive smoking in children aged 5-11 years. DESIGN: The study was an analysis of existing observational studies, comprising three samples: English representative; English inner city; Scottish representative. SETTING: Primary schools (children aged 5-11 years). PARTICIPANTS: The study population included 5002 English children from the representative sample (69.1% of total eligible), 2903 English inner city children (42.0%), and 3319 representative Scottish children (75.6%). MEASUREMENTS AND MAIN RESULTS: No significant relation was found between child's height and total parental smoking in the home. Relative risk for persistent wheeze on exposure to 20 cigarettes per day was 1.35, compared to no exposure. Risk of at least one respiratory condition attributable to passive smoking reached 8.1% in white English inner city children. CONCLUSIONS: The relation of child's height to passive smoking was not substantiated. The risk of respiratory conditions resulting from passive smoking, although small, is not negligible.

Asthma↗
PubMed1990

Has the prevalence of asthma increased in children? Evidence from the national study of health and growth 1973-86.

OBJECTIVES: To estimate changes in the prevalence of reported symptoms of respiratory disease and reported diagnoses of asthma and bronchitis in primary school children in England between 1973 and 1986. DESIGN: Mixed longitudinal survey. SETTING: Representative sample of English primary schools in 22 areas. PARTICIPANTS: 15,000 Boys and 14,156 girls each studied at least once between 1973 and 1986. DATA COLLECTED: Whether, according to the parent or guardian, the child had wheezed, wheezed on most days or nights, or had attacks of bronchitis or asthma in the past year. RESULTS: Within age groups trends in successive annual cohorts showed an increasing prevalence of asthma for each annual birth cohort (boys, 6.9%, p less than 0.001; girls, 12.8%, p less than 0.001) and of wheeze on most days or nights (boys, 4.3% per cohort, p less than 0.001; girls, 6.1% per cohort, p less than 0.001) and a falling prevalence of bronchitis (boys, -4.7% per cohort, p less than 0.001; girls, -5.8% per cohort, p less than 0.001). There was a smaller increase in the prevalence of wheeze whether or not it occurred on most days or nights, and this increase was significant only among the girls (boys, 1.0% per cohort, p greater than 0.05; girls, 1.7% per cohort, p less than 0.05). Although the rate of increase of "asthma" was greater than the rate of decrease in "bronchitis," the baseline prevalence of asthma was much lower than that of bronchitis, and the total proportion of children with either diagnosis declined slightly over the whole period. The main change was an increase in the proportion of children whose parents stated that they had persistent wheeze and yet did not have a report of either "asthma" or "bronchitis." CONCLUSIONS: These results suggest that there has been a true increase in morbidity that is not simply due to changes in diagnostic fashion. The increase is large enough to explain much if not all of the increase in admission to hospital and mortality, and it underlines the importance of an understanding of the aetiology of asthma in tackling the causes of the recent increase.

Asthma↗
PubMed1990

Associations of excessive irritability with common illnesses and food intolerance.

In a national study of almost 7000 primary school children, parents' perceptions were used to test the hypothesis that the child's irritability was associated with food intolerance independently of other symptoms. After adjustment in a multiple regression analysis for asthma or wheeze, cough, eczema, hives, diarrhoea and vomiting, rhinitis, hay fever and headache, and the social factors of father's social class, maternal education and maternal age, a highly significant association between perception of food intolerance and irritability (P less than 0.001) remained. Though we cannot rule out that irritable children's parents could be biased towards diagnosing food intolerance the possibility that some children do have behavioural disturbance associated with reactions to food needs to be explored further, preferably with a double blind challenge assessment.

Affect↗
PubMed1990

Sleep habits and height at ages 5 to 11.

Shorter durations of slow wave sleep and lower growth hormone responses have been reported in children with short stature caused by psychosocial deprivation. We investigated whether lower total sleep duration was associated with shorter stature in a sample of children taking part in the National Study of Health and Growth. Parental responses to a self administered questionnaire were used to estimate usual times for going to sleep at night and usual times for waking in the morning for 5145 children aged 5 to 11 years of age. After adjusting for the effects of other variables known to be associated with height, it was shown that there was a weak negative association between sleep duration and height. It is concluded that variation in sleep duration between children is unlikely to have an important influence on growth.

Body Height↗
PubMed1989

Validity and repeatability of self-reported occupational and industrial history from patients in EEC countries.

The results of a study to assess the feasibility and acceptability of a questionnaire designed to ascertain occupational history and the repeatability of coding occupational and industrial status using an abbreviated version of the coding status are presented for EEC countries. The study demonstrates the difficulty of recruiting cancer patients below age 65. The percentage of useful information among patients who completed a self-administered questionnaire was slightly lower than those who completed an administered questionnaire but in general the response rate for most items in the questionnaires in any group was above 90%. The repeatability of coding occupational status and industrial status for current or last job was satisfactory with Kappa values of 65% and 76% respectively. The within-individual repeatability for these variables had similar Kappa values. The validity of coding occupational status with an abbreviated version of coding status compared to the full instructions was satisfactory for current or last occupation. However, observer variability may be fairly large for the abbreviated version. An increase in the coding repeatability could probably be achieved with few modifications to the description of occupation status groups and clearer headings for each division of the Industrial Occupation Classification and greater training of coders.

Adult↗
PubMed1989

Need for new reference curves for height.

Data from the National Study for Health and Growth, on children aged from 4.0 to 12.0 years measured in 1972, 1985, and 1986 were used to assess whether new growth standards are required, and which subgroups of children might require separate standards. The change over this period, from just over half a centimetre in the youngest girls to over a centimetre in the oldest boys, warrants the use of revised reference curves, which are also needed for Afro-Caribbean children.

Body Height↗
PubMed1989

Referral patterns after school medical examinations.

The incidence of sensory or language abnormalities and the factors influencing the clinical medical officers' decisions to refer children who failed developmental tests were studied. There were 1259 children examined and referrals for vision, hearing, and language assessment were made for 39(3.1%), 75(6.0%), and 27(2.1%), respectively. About 80% of these problems, however, were not known to the child health services when the children were 3.5 years old, mainly because children had moved to the district after the age of 3.5, and did not attend the 3.5 year screening clinics. Referrals formed only a small percentage of children who failed a test (11.0% failed vision, 19.5% hearing, and 24.6% language assessments). For vision and hearing the most important reason for the discrepancy was the clinical medical officers' wish to reassess children who failed the test before referring them. For the language test the clinical medical officer's often believed that the screening did not reflect the child's skills, which suggests that language screening as currently used in the district is not effective. Evaluation of the examination has highlighted the need to review the tests being used.

Child, Preschool↗
PubMed1989

School meals, school milk and height of primary school children in England and Scotland in the eighties.

In a nutritional surveillance system of primary school children in England and Scotland we assessed the possible effects on height gain of changes in school meals and school milk policies following the 1980 Education Act (No. 2). Mean height and height gain were estimated separately for English and Scottish samples from 1982 to 1984, and for a selective sample of inner city areas with a high proportion of ethnic minorities from 1983 to 1985 in children from 5.00 to 9.99 years. Children receiving free school meals were smaller than children paying for school meals or receiving a meal prepared elsewhere, while children receiving free school milk were of similar stature to other children in the study. The rate of growth was assessed in children receiving school meals or lunches prepared at home, and in those for whom arrangements changed during the study period; it was also assessed in those children for whom school milk was available, not available, or for whom the provision changed. No consistent association was found between provision of school meals or school milk and the rate of growth in the three samples studied when stratified according to poverty status and ethnic background. We conclude that this observational study does not provide any evidence that the current availability of school meals or school milk increases the rate of growth of primary school children in any social stratum.

Animals↗
PubMed1989

Demand for DNA probe testing in three genetic centres in Britain (August 1986 to July 1987).

We report a preliminary analysis of the data collected during the first year of the evaluation of clinical genetics in the context of DNA probes in three genetic centres, to show the pattern of the demand for genetic services in the three centres and the services used in meeting that demand. The analysis includes information on 10,185 persons from 2852 families. The results are presented according to mode of inheritance and according to the most common disorders for which DNA probes have been used in the three centres. The results indicate that the use of DNA probes is now a major element of activity in genetic departments, and that as long as indirect DNA probe testing is the predominant manner of using recombinant technology, the clinical input will be an important element of the costs, probably more so than that of the DNA laboratories, as a large number of family members needs to be tested. In most cases centres have concentrated activity on DNA testing for common and severe genetic disorders. However, there are disorders, such as familial hypercholesterolaemia, which have not been part of the established pattern of services. Conversely, a relatively high number of families have been studied for some disorders of very low incidence. This suggests that the number of DNA laboratories should be limited. The precise arrangements will need to be established. With such services the distribution of DNA testing facilities for different disorders can be controlled to limit duplication. The model followed in Scotland based on collaboration between centres is worth considering. We have detected very large differences in take up rate of services within and between regions. Although many factors may contribute to these differences, ease of access and lay and professional awareness are probably the most important. This is supported by the fact that more patients from the same or neighbouring DHAs attend the genetic centre than from those further away. We also concluded that published guidelines for clinicians in general on the uses of DNA probes, the type of families that could benefit, and the centres to which referrals should be sent would be very useful in increasing coverage and maximising the effectiveness of the services. Since this may increase demand, this educative tool should be coordinated and agreed by the Departments of Health with all the genetic departments and centres in the country.

DNA Probes↗
PubMed1989

Genetic services in the context of DNA probes: what do they cost?

We describe results from the first year of a three year economic evaluation of genetic services in the context of DNA probes provided at three genetic centres in Great Britain. The analysis so far has concentrated on the costs of providing DNA diagnostic services. Estimates are given of the total costs of providing DNA probe services at each of the three centres, together with information for assessing the cost implications of future developments in these services. DNA probe services are likely to be funded as a Regional specialty. This paper concludes that relative to other developing medical technologies and as an investment by Regions, DNA probe services are inexpensive. An appraisal of the benefits to be derived from DNA probe services is still to be undertaken.

Cost-Benefit Analysis↗