Breastfeeding and the risk of sudden infant death syndrome

The New Zealand Cot Death Study, a multicentre case-control study, was set up to identify risk factors associated with sudden infant death syndrome (SIDS). In the 3 years of the study there were 485 infant deaths classified as SIDS in the study areas and 1800 infants who were randomly selected as controls. Data were collected by parent interviews and from obstetric notes. A full set of data for this analysis was available from 356 cases and 1529 control infants. The relationship between length of any breastfeeding and SIDS was examined: 92% of the controls were initially breastfed compared to 86% of the cases. As time went by, cases stopped breastfeeding sooner than controls: by 13 weeks, 67% controls were breastfed versus 49% cases. A reduced risk for SIDS in breastfed infants persisted during the first 6 months after controlling for confounding demographic, maternal and infant factors. Infants exclusively breastfed 'at discharge from the obstetric hospital' (odds ratio [OR] = 0.52, 95% confidence interval (CI): 0.35-0.71) and during the last 2 days (OR = 0.65, 95% CI: 0.46-0.91) had a significantly lower risk of SIDS than infants not breastfed after controlling for potential confounders. We have shown a substantial association of breastfeeding with a lowered risk for SIDS. This supports the need for more positive promotion and active community support to further enhance the level and length of exclusive breastfeeding.

Smoking and the sudden infant death syndrome

OBJECTIVE

Maternal smoking has been shown to be a risk factor for sudden infant death syndrome (SIDS). The effect of smoking by the father and other household members has not previously been examined.

METHODS

A large nationwide case-control study. Four hundred eighty-five SIDS deaths in the postneonatal age group were compared with 1800 control infants.

RESULTS

Infants of mothers who smoked during pregnancy had a 4.09 (95% confidence interval [CI] = 3.28, 5.11) greater risk of death than infants of mothers who did not smoke. Infants of mothers who smoked postnatally also had an increased risk of SIDS compared with infants of nonsmokers and, furthermore, the risk increased with increasing levels of maternal smoking. Smoking by the father and other household members increased the risk (odds ratio [OR] = 2.41, 95% CI = 1.92, 3.02 and OR = 1.54, 95% CI = 1.20, 1.99, respectively). Smoking by the father increased the risk of SIDS if the mother smoked, but had no effect if she did not smoke. In analyses controlled for a wide range of potential confounders, smoking by the mother and father was still significantly associated with an increased risk of SIDS.

CONCLUSION

Passive tobacco smoking is causally related to SIDS.

Dummies and the sudden infant death syndrome

The association between dummy use and sudden infant death syndrome (SIDS) was investigated in 485 deaths due to SIDS in the postneonatal age group and compared with 1800 control infants. Parental interviews were completed in 87% of subjects. The prevalence of dummy use in New Zealand is low and varies within New Zealand. Dummy use in the two week period before death was less in cases of SIDS than in the last two weeks for controls (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.57 to 1.02). Use of a dummy in the last sleep for cases of SIDS or in the nominated sleep for controls was significantly less in cases than controls (OR 0.44, 95% CI 0.26 to 0.73). The OR changed very little after controlling for a wide range of potential confounders. It is concluded that dummy use may protect against SIDS, but this observation needs to be repeated before dummies can be recommended for this purpose. If dummy sucking is protective then it is one of several factors that may explain the higher mortality from SIDS in New Zealand than in other countries, and may also explain in part the regional variation within New Zealand.

Evaluation of the cot death prevention programme in South Auckland

AIMS

The National Cot Death Prevention Programme aims to reduce the prevalence of four modifiable risk factors for cot death, namely infant sleeping prone, maternal smoking, lack of breast feeding and infant sharing a bed with another person. This study evaluated the knowledge of 200 mothers of infants in South Auckland and estimated the prevalence of these infant care practices, which were compared with that found in the New Zealand Cot Death Study.

METHODS

200 mothers were interviewed.

RESULTS

The prevalence of these modifiable risk factors in this study and that found in 1987/89 in Auckland were: prone sleep position: 2.5% compared with 36.8%, p < 0.001; infant sharing a bed with another person: 23.5% and 45.2%, p < 0.001; maternal smoking: 24.0% and 26.1%, p = ns; lack of breast feeding at 4 weeks of age: 11.0% and 13.6%, p = ns. The following percentage of mothers knew that there were risk factors for cot death: prone sleep position 95.5%, maternal smoking 89.4%, lack of breast feeding 63.1% and infant sharing a bed with another person 68.0%.

CONCLUSIONS

This study shows that infant care practices are changing and highlights the need for continuing efforts, especially relating to maternal smoking and the practice of infants sharing a bed with another person.

Ethnic differences in mortality from sudden infant death syndrome in New Zealand

OBJECTIVES

To examine the factors which might explain the higher mortality from sudden infant death syndrome in Maori infants (7.4/1000 live births in 1986 compared with 3.6 in non-Maori children).

DESIGN

A large nationwide case control study.

SETTING

New Zealand. 485 infants who died of sudden infant death syndrome were compared with 1800 control infants. There were 229 Maori and 240 non-Maori cases of sudden infant death syndrome (16 cases unassigned) and 353 Maori and 1410 non-Maori controls (37 unassigned).

RESULTS

Maori infants had 3.81 times the risk (95% confidence interval 3.06 to 4.76) of sudden infant death syndrome compared with non-Maori infants. The risk factors for sudden infant death syndrome within groups were remarkably similar. When Maori and non-Maori controls were compared the prevalence of many of the known risk factors was higher in Maori infants. In particular, mothers were socioeconomically disadvantaged, younger, and more likely to smoke and their infants were of lower birth weight and more likely to share a bed with another person. Multivariate analysis controlling for potential confounders found that simply being Maori increased the risk of sudden infant death syndrome by only 1.37 (95% CI = 0.95 to 2.01), not statistically significantly different from 1. Population attributable risk was calculated for prone sleeping position, maternal smoking, not breast feeding, and infants sharing a bed with another person. In total these four risk factors accounted for 89% of deaths from sudden infant death syndrome in Maori infants and 79% in non-Maori infants.

CONCLUSION

The high rate of sudden infant death syndrome among Maori infants is based largely on the high prevalence in the Maori population of the major risk factors. Other risk factors, not related to ethnicity, probably explain remaining differences between Maori and non-Maori children.

Asthma knowledge and management in primary schools in south Auckland

AIMS

to examine the management of asthma in primary schools and the school teachers' knowledge, confidence and attitude in managing the pupils with asthma.

METHODS

forty-two primary schools in south Auckland were randomly selected to participate. Questionnaires were posted out to the principals and another questionnaire was given randomly to 253 teachers from these primary schools.

RESULTS

76% of the school principals surveyed returned the questionnaire; and 66% of the school teachers surveyed returned a separate questionnaire. The average incidence of asthma reported by school principals and school teachers was 9.9% and 12.6% respectively, which suggests underreporting of the diagnosis of asthma. In 81% of the schools a questionnaire was used to identify students with asthma when they first join the school. School teachers had good basic knowledge on asthma, however 33% of teachers did not know that Ventolin (salbutamol) is for symptomatic treatment and 58% and 65% of teachers did not know that Becotide (beclomethasone) and Intal (sodium cromoglycate) are prophylactic medications.

CONCLUSIONS

we suggest that primary school teachers should receive further education on asthma, especially on practical aspects of asthma management.

The national cot death prevention program in New Zealand

A case-control study examining the risk factors for sudden infant death syndrome (SIDS) in New Zealand identified three risk factors that are potentially amenable to modification: prone sleeping position of the infant, maternal smoking and lack of breastfeeding. In total these three risk factors may account for 79 per cent of deaths from SIDS in New Zealand. We describe the planning and implementation of the cot death prevention program, which has involved a wide range of groups and different strategies. The outcome of the prevention program is being evaluated.

Postnatal depression and SIDS: a prospective study

This study was carried out in response to reports from nurses to a post-neonatal mortality review committee that a number of mothers of infants dying from sudden infant death syndrome (SIDS) appeared to be depressed before the child's death. The New Zealand Cot Death Study was a 3 year multicentre case-control study for SIDS. There were 485 SIDS cases in the post-neonatal age group in the study regions, and these were compared with 1800 control infants. Infants of mothers with either a self-reported use of medication for psychiatric disorders, a history of hospitalization for psychiatric illness or a family history of postnatal depression had a significantly increased risk of SIDS compared with infants of mothers who were either not using medication (odds ratio (OR) = 1.45; 95% confidence interval (CI) = 1.03, 2.04) or were without a history of hospitalization for psychiatric illness (OR = 1.80; 95% CI = 1.03, 3.11) or a family history of postnatal depression (OR = 1.61; 95% CI = 1.06, 2.43). All mothers of infants born in the study areas over a 1 year period were eligible to complete a questionnaire measuring maternal depression when the infant was 4 weeks of age. Thirty-three infants subsequently died from SIDS, and they were compared with 174 controls. Fifteen (45.5%) of the mothers of cases were depressed, compared with 28 (16.1%) of the mothers of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Four modifiable and other major risk factors for cot death: the New Zealand study

New Zealand's high mortality rate from sudden infant death syndrome (SIDS) prompted the development of the New Zealand Cot Death Study. A report of the analysis of the data from the first year has been published. This report now gives the major identified risk factors from the full 3 year data set. In this case-control study there were 485 infants who died from SIDS in the post-neonatal age group, and 1800 control infants, who were a representative sample of all hospital births in the study region. Obstetric records were examined and parental interviews were completed in 97.5% and 86.9% of subjects, respectively. As expected many risk factors for SIDS were confirmed including: lower socio-economic status, unmarried mother, young mother, younger school-leaving age of mother, younger age of mother at first pregnancy, late attendance at antenatal clinic, non-attendance at antenatal classes, Maori, greater number of previous pregnancies, the further south the domicile, winter, low birthweight, short gestation, male infant and admission to a special care baby unit. In addition, however, we identified four risk factors that are potentially amenable to modification.(ABSTRACT TRUNCATED AT 250 WORDS)

The New Zealand Cot Death Study: some legal and ethical issues

The New Zealand Cot Death Study is a 3 year multicentre case-control study aimed at identifying the risk factors for sudden infant death syndrome (SIDS). The paper describes some of the legal and ethical issues which arose in the planning, implementation and analysis of the study.

Further evidence supporting a causal relationship between prone sleeping position and SIDS

A 3 year case-control study identifying the risk factors for SIDS was undertaken. Preliminary analysis of the data from the first year suggested that SIDS mortality could fall by 50% if the prevalence of the prone sleeping position changed from 40 to 0%. During the 3 year study the prevalence of the prone sleeping position among infants has fallen from 43% in the first year to 20% in the third year. SIDS mortality has fallen to 3.1/1000 live births, which is very close to that predicted. When considered with other available evidence this strongly supports a causal relationship between the prone sleeping position and SIDS.

Sudden infant death syndrome and weather temperature

The relationship between the days on which sudden infant death syndrome (SIDS) occurred and the daily minimum temperature was examined in Auckland (1979-1984) and Christchurch (1979-1987). There was a marked winter excess of deaths in both regions. There was a significant negative correlation between the monthly mean minimum temperature and SIDS rate for both regions (r = -0.43, n = 347, P less than 0.0001). The monthly mean minimum temperature describes SIDS mortality equally as well as the three variables of daily minimum temperature, season and geographical location. There was a significant association of SIDS with minimum temperature 4 and 5 days prior to the death after adjusting for the effect of monthly mean minimum temperature. The days preceding death were on average colder than the other days, but the effect was small, especially when compared with the magnitude of the temperature differences between consecutive months.

Results from the first year of the New Zealand cot death study

New Zealand's high mortality rate from the sudden infant death syndrome (SIDS) prompted the development of the New Zealand cot death study. This report of the preliminary analysis of the first year of the data gives the major identified risk factors. One hundred and sixty-two infants who died from SIDS were compared with 589 control infants, who were a representative sample of all hospital births in the study region. Obstetric records were examined and parental interviews were completed in 96% and 89% of subjects respectively. Data were available for all the variables in this study in 95% of those interviewed, thus 128 cases and 503 controls make up the subjects of this report. As expected we confirmed many risk factors for SIDS including: lower socioeconomic status, unmarried mother, young mother, younger school leaving age of mother, younger age of mother at first pregnancy, late attendance at antenatal clinic, nonattendant at antenatal classes, Maori, greater number of previous pregnancies, lower birth weight, shorter gestation, male infant, admission to neonatal intensive care unit. In addition, however, we identified three risk factors which are potentially amenable to modification. These were the prone sleeping position of baby (odds ratio = 3.53, 95% confidence interval 2.26, 5.54), maternal smoking (1-9 cigarettes/day OR = 1.87, 95% CI = 0.98, 3.54; 10-19/day OR = 2.64, 95% CI = 1.47, 4.74; 20+/day OR = 5.06, 95% CI = 2.86, 8.95) and breast feeding (OR = 2.93, 95% CI = 1.84, 4.67).(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroanatomical structures involved in the action of the 5-HT3 antagonist ondansetron: a 2-deoxyglucose autoradiographic study in the rat

Local cerebral glucose utilization following the acute administration of the 5-HT3 receptor antagonist ondansetron (0.01-1.0 mg/kg) was determined using [14C]2-deoxyglucose quantitative autoradiography. Ondansetron effected alterations in 13 of the 66 brain areas analyzed including limbic, auditory and visual structures. In the majority of these 13 regions ondansetron was only effective at reducing glucose use compared to control values at a dose of 0.01 mg/kg. Thus in limbic and related areas (CA2 and CA3 fields of the hippocampus, lateral habenula and septal nucleus) glucose utilization was reduced by 15-21%. Similar reductions (18-20%) were apparent in primary auditory and visual areas (auditory cortex, medial geniculate and visual cortex). However, with the exception of the ventromedial thalamic nucleus (14% reduction) glucose use in extrapyramidal and sensory motor areas was unchanged. Following larger doses of ondansetron (0.1 and 1.0 mg/kg), there was no change in cerebral glucose utilization relative to control values, with the exception of the median raphe. In this structure local cerebral glucose utilization was significantly increased (P less than 0.05) following administration of 1.0 mg/kg ondansetron relative to the lower dose of 0.01 mg/kg. Changes in glucose use did not always reflect areas of high 5-HT3 receptor density. Thus, although cerebral glucose use was reduced in hippocampal layers, it was unchanged in the entorhinal cortex and the area postrema. These data suggest that under these experimental conditions ondansetron produces modest changes in glucose utilization which are primarily confined to limbic structures and those involved in sensory processing.

A tool for measuring the asthma self-management competency of families

A tool for measuring a family's asthma self-management behaviour has been developed for a study examining the relationships of asthma self-management behaviour, knowledge, and psychosocial factors with various indices of morbidity in children with asthma. The tool involves a structured interview which includes three typical situations of asthma self-management (scenarios). Each of the scenarios is divided into graded challenges. A scoring schedule was developed according to the critical incidents of self-management inherent in each situation. This schedule was then applied to the verbatim transcripts of the subjects' responses. These were presented to 380 asthmatic children aged 5-11 yr and their primary caregivers. Inter-rater reliability, inter-rater agreement and test-retest reliability coefficients indicate that the scores obtained are stable across raters and time. Correlations between scores on different scenarios suggest there is a common factor of self-management competency across all scenarios, but families are better at some aspects of self-management than others. The distribution of scores for each scenario is presented. The place of this tool as a means of assessing self-management behaviour is discussed.

Racial inequalities in childhood asthma

Mortality and hospital admission rates for asthma are higher in Maoris and Pacific Islander children than in European children. These ethnic differences are not explained by ethnic differences in asthma prevalence, the characteristics of the disease or admission criteria. There are major ethnic differences in asthma drug management both in the community and at the time of discharge from hospital. In particular Polynesians were less likely to receive prophylactic therapy and this factor probably accounts for ethnic differences in mortality and admission rates. Possible explanations for the ethnic differences in medical management are discussed.

Evaluation and outcome of the vision screening programme in south Auckland intermediate schools

Four thousand, seven hundred and fifty-nine form 1 intermediate school children (aged 11 years) in the south Auckland health district were screened in 1987. There were 88 (1.8%) new visual defects detected (defined as a visual acuity (VA) of 6/12 or worse in one or both eyes), while 103 (2.2%) wore glasses and a further 22 (0.5%) did not have their glasses available at the time of the VA test. The total prevalence of screening visual defects was 4.5%. A survey was carried out of those pupils who failed the VA screening test in the previous year and those recorded as wearing glasses. Sixty-seven (76%) of 88 children with newly detected visual defects were interviewed. An abnormal VA test was confirmed in 59 (88%), of which 39 (66%) required treatment. Thirty were prescribed glasses, of which 27 purchased them, but at the time of interview nine did not have them available. Twenty-one (20%) of the 103 children tested with glasses failed the VA test. Twenty-two children had glasses but were not wearing them at the time of the VA test. Only three of these children had a VA better than 6/12 bilaterally. These results highlight the importance of the vision screening programme in this age group and the follow up of children with known visual defects.

The interrelationship among bronchial hyperresponsiveness, the diagnosis of asthma, and asthma symptoms

Bronchial hyperresponsiveness (BHR) to inhaled histamine has often been cited as the gold standard in asthma diagnosis, but recently this has been questioned. This report assesses the relationship of BHR to asthma symptoms and asthma diagnosis in a large community-based sample of children. A total of 2,053 children 7 to 10 yr of age were randomly sampled from Auckland primary schools and assessed by a questionnaire and histamine inhalation challenge. In all, 14.3% had had asthma diagnosed, 29.6% reported having had one of the four respiratory symptoms in in the previous 12 months, and 15.9% had BHR (PD20 less than or equal to 7.8 mumol histamine). After a cumulative dose of 3.9 mumol histamine, the percent change in FEV1 from postsaline FEV1 was unimodally distributed, with those in whom asthma had been diagnosed dominating the severe end of the spectrum. However, 53% of those with BHR had no asthma diagnosis, and 41% had no current asthma symptoms. On the other hand, 48% of all subjects with diagnosed asthma and 42% of children with diagnosed asthma and current symptoms did not have BHR. Although severity of BHR tended to increase with wheezing frequency, all grades of severity (including no BHR) were found for any given frequency of wheeze. An existing diagnosis of asthma identified symptomatic children more accurately than did BHR, regardless of the criteria used for BHR or for "symptomatic" and irrespective of ethnic group. In conclusion, BHR is related to, but not identical to, clinical asthma. Bronchial challenge testing is an important tool of respiratory research, but cannot reliably or precisely separate asthmatics from nonasthmatics in the general community.

International trends in postneonatal mortality

Trends in mortality in the age groups 1-5 and 6-11 months from 1966 to 1987 for Australia, Canada, England and Wales, New Zealand, and Sweden were examined. Mortality rates for ages 1-5 months differed appreciably between countries, with Sweden lower than all other countries examined. Rates have decreased in Australia, Canada, and England and Wales, but increased in New Zealand and Sweden. Mortality reported as due to the sudden death syndrome (SIDS) increased dramatically in all countries, although much of the increase was probably due to diagnostic transfer from respiratory diseases. Over 80% of SIDS deaths occurred in the age group 1-5 months and SIDS accounted for about half of all deaths in this age group. For developed countries total mortality in those aged 1-5 months was an indirect measure of SIDS mortality. A real increase in SIDS has thus occurred in Sweden and New Zealand and possibly in other countries as well. Mortality in the age group 6-11 months has approximately halved in all countries examined over the study period.

Why are hospital admission and mortality rates for childhood asthma higher in New Zealand than in the United Kingdom?

New Zealand has higher mortality and hospital admission rates for asthma than England and Wales. To determine the reasons for this the available data on asthma mortality and hospital admissions from the Auckland region of New Zealand were compared with data from the South West Thames Region of England for 1979-86 and data from previous surveys on prevalence of wheeze (Auckland 1985, Croydon 1978). In addition, a survey of general practitioners was carried out to determine their approach to the management of asthma, patient simulations being used. Asthma mortality in children of European descent aged 5-14 years was 2.5 times higher in Auckland than in South West Thames. The reported lifetime, 12 month, and one month prevalences of wheeze were also higher in Auckland (by 18.5%, 32.1%, and 87.5%). Unexpectedly, the hospital admission rate for asthma in children of European descent aged 5-14 years was 5% less in Auckland than in South West Thames. Comparative studies of hospital case notes and of the replies from general practitioners showed that in Auckland the duration of illness before admission was greater and that general practitioners were less likely to admit patients with acute asthma. The overall standard of general practitioner care in Auckland was, if anything, higher than in South West Thames but in both areas there was considerable variation. On balance it was concluded that the higher mortality rate in New Zealand is explained by higher levels of morbidity rather than relative deficiencies in care. Nevertheless, the implications of the lesser use of hospital care for acute asthma observed in Auckland need further consideration.

Maori and nonMaori postneonatal mortality rates by domicile

The urbanisation of Maori with the possible loss of family and cultural ties may in part account for the higher Maori postneonatal mortality rate compared with nonMaori. To examine this hypothesis rural and urban postneonatal mortality rates by region and ethnic group were compared. In the North Island regions there was no significant difference between the urban and rural rates of either ethnic group. In the South Island the rate for Maori in the rural areas (7.51/1000 live births) was lower (RR = 0.45, 95%CI = 0.17-1.17) than in the urban areas (16.83/1000).

Socioeconomic status in childhood asthma

This study examines the relationship between socioeconomic status (SES) and asthma prevalence and the use of asthma medication. One thousand and fifty European children aged eight and nine years were studied by parent completed questionnaire and histamine inhalation challenge. After controlling for sex of the child and for smokers in the house there were significantly higher lifetime (P = 0.029) and current (P = 0.046) prevalence rates of wheeze in children in low SES groups. There was no relationship between SES and asthma diagnosis, bronchial hyperresponsiveness (BHR: PD20 less than 7.8 mumol), or any combination of BHR with symptoms or diagnosis. The use of bronchodilators and asthma prophylactic drugs was less frequent in the low SES groups of children with wheeze in the last 12 months both with concurrent BHR or irrespective of BHR than in those in high SES groups.

Why are hospital admissions of children with acute asthma increasing?

The hospital admission rate for asthma has increased in many countries. Particularly prominent has been the increase for children, especially male children under five yrs. The increased admission rate refers to increased number of individuals and to increased frequency per individual. The moderate increase in asthma prevalence does not account for the large increase in admissions. Various other factors are discussed here, such as changes in admission criteria, medical management, and/or clinical expression of the disease.

Why are hospital admissions of children with acute asthma increasing?

The hospital admission rate for asthma has increased in many countries. Particularly prominent has been the increase for children, especially male children under five yrs. The increased admission rate refers to increased number of individuals and to increased frequency per individual. The moderate increase in asthma prevalence does not account for the large increase in admissions. Various other factors are discussed here, such as changes in admission criteria, medical management, and/or clinical expression of the disease.

Ethnic differences in prevalence of asthma symptoms and bronchial hyperresponsiveness in New Zealand schoolchildren

Maoris and Pacific Islanders in New Zealand have a higher asthma mortality and hospital admission rates than Europeans. To determine whether difference in asthma prevalence is the major factor underlying these differences in mortality, 2053 Auckland children aged 7-10 years (European 1084, Maori 509, Pacific Islander 460) were randomly sampled from school classes in the Auckland Urban Area, and studied by questionnaire (completed by parents) and histamine inhalation challenge to assess the provocative dose of histamine causing a 20% fall in FEV1 (PD20). Maoris had the highest prevalence rates of respiratory symptoms, and Europeans had rates similar to Pacific Islanders. For "any current wheeze" for example, the prevalence in Maoris was 22.2% compared with 16.1% and 16.3% in the Europeans and Pacific Islanders. The prevalence of diagnosed asthma was similar in the three groups. When bronchial hyperresponsiveness (defined as a PD20 less than or equal to 7.8 mumol histamine) was considered, Europeans had the highest rates (20%), followed by Maoris (13%), and then Pacific Islanders (8.7%). These differences were not accounted for by differences in socioeconomic status, rates of smoking in the home, age, gender, or height. It is concluded that differences in asthma prevalence do not satisfactorily explain the mortality and admission rate differences, although the higher symptom prevalence in the Maoris could be relevant to the higher mortality rate. Maori and Pacific Island children with symptoms of asthma were less likely to be taking prophylactic medication than European children. It is proposed that differences in management are important factors relevant to the increased mortality and morbidity from asthma in Polynesians.

Recent trends in asthma mortality, morbidity, and management in New Zealand

Trends in mortality and hospital admission rates, prevalence, and drug sales, relating to asthma in New Zealand since 1960 were examined. Two epidemics of asthma death among people in the age range of 15-64 years occurred during this period with peak mortality rates more than four times pre-epidemic rates. Death from asthma was nevertheless rare compared with hospital admissions which have increased 20-fold in children and three- to fivefold in adults between 1960 and 1985. Asthma drug sales have also risen dramatically, particularly in the late 1970s when it is likely that a major change in the drug management of asthma occurred. Changes in asthma prevalence and severity may account in part for the increasing hospital admissions rates. However, the lack of any clear relationship between hospital admissions and death rates and the abrupt time course of the mortality epidemics suggest that changes in the management rather than in the disease itself may be responsible for the increased number of asthma deaths.

Deaths from sudden infant death syndrome on public holidays and weekends

Deaths from sudden infant death syndrome (SIDS) between 1979 and 1984 were tabulated by month for weekdays, weekends and public holidays. Examination of deaths by day of the week showed the weekend had more deaths than the weekdays (chi 2 = 26.3, df = 6, p = 0.0002) and that this pattern occurred in both the under three months and three-11 months age group. There were 40 deaths on the 78 public holidays in the six years under study. Modelling the data showed that there was no difference between the number of deaths on holidays compared to weekends.

International comparison of the prevalence of asthma symptoms and bronchial hyperresponsiveness

Potential explanations for the higher rates of asthma mortality and hospital admissions in New Zealand (NZ) include greater prevalence of asthma. To evaluate this further, a large community survey has been undertaken. Rates of respiratory symptoms and bronchial hyperresponsiveness (BHR) for children in Auckland, NZ have been compared to those for children in two locations in New South Wales (NSW), Australia: Wagga Wagga (inland) and Belmont (coastal). The methodology used was the same in both studies: parent-completed questionnaire and BHR measured by response to an abbreviated histamine challenge. In Auckland, 1,084 children participated (84% of those selected) and were compared to 769 inland NSW and 718 coastal NSW children. The prevalence of respiratory symptoms, BHR, severity of BHR, and BHR combined with symptoms was similar among Auckland and inland NSW children but lower among coastal NSW children than those from the other two sites. It is concluded that other unidentified factors must be invoked to explain mortality and admission differences between these regions.

Why are Polynesian children admitted to hospital for asthma more frequently than European children?

Polynesian children have higher hospital admission rates than European children. This study compared 156 Polynesian children with 199 European children admitted to hospital for asthma. After controlling for socioeconomic status Polynesian children were similar to European children for many variables, but there were a number of important differences. The number of previous hospital admissions for asthma was higher in Polynesians than Europeans (mean (SD), 3.9 (4.6) v 2.8 (3.8) respectively p = 0.028). Despite this, 33% of Polynesian children were not receiving any asthma drugs in the 24 hours prior to admission to hospital compared with 14% of Europeans (relative risk (RR) = 1.94, 95% confidence interval (CI) = 1.25-3.00) and fewer were taking sympathomimetics and cromoglycate. A similar trend in asthma drug usage was seen six months later. Polynesian children were less likely to be referred to hospital by a general practitioner than European children (42% v 64% respectively, RR = 0.72 95% CI = 0.58-0.89). The differences in hospital admission rates are not explained by genetic or socioeconomic factors but seem to be related more to patterns of medical management.

Comparison of the characteristics of children with multiple admissions to hospital for asthma with those with a single admission

Hospital admission rates in children for asthma have increased strikingly and part of this increase is due to an increase in the readmission rate. The study compared the characteristics of European children with multiple admission to hospital for asthma with those having their first admission for asthma. The number and magnitude of the differences found were small. Differences found included asthma drug management in the 24 hours prior to the index admission and six months later and days lost from school. Twenty-four percent of study population were readmitted within six months. The number of parents who smoked and the number of pets in the home are of concern and the lack of difference between the multiple and single admission groups suggest our education efforts are ineffectual at altering parental behaviour.