Household interventions for prevention of domestic lead exposure in children.

BACKGROUND: Lead poisoning is associated with physical, cognitive and neurobehavioral impairment in children and many household interventions to prevent lead exposure have been trialled. OBJECTIVES: To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development. SEARCH STRATEGY: Trials were identified through electronic searches of CENTRAL 2006 (Issue 1), MEDLINE 1966 to March 2006, and thirteen other electronic databases and contacting experts to find unpublished studies. SELECTION CRITERIA: Randomised and quasi randomised trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported. DATA COLLECTION AND ANALYSIS: Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. Triallists were contacted to obtain missing information. MAIN RESULTS: Twelve studies (2239 children) were included. All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. Studies were subgrouped according to their intervention type. Meta-analysis of both continuous and dichotomous data was performed for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: WMD 0.13, 95% CI -0.30, 0.56, I2 = 41.6; dichotomous >/= 10 microg/dL (>/= 0.48 micromol/l): RR 1.02 (95% CI 0.79, 1.30, I2 = 0); dichotomous >/= 15 microg/dL (>/=0.72 micromol/l): RR 0.60, 95% CI 0.33, 1.09, I2 = 0). Meta-analysis of the dichotomous data for the dust control subgroup found no evidence of effectiveness. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies. AUTHORS' CONCLUSIONS: Currently there is no evidence of effectiveness for household interventions for education or dust control measures in reducing blood lead levels in children as a population health measure. There is insufficient evidence for soil abatement or combination interventions. Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements should include longer term follow up and measures of compliance as well as performing trials in developing countries and differing socio-economic groups in developed countries.

Social capital: a key factor in child health inequalities.

The widening gap in health outcomes between rich and poor is particularly evident among children and social inequalities in health are therefore of great concern to readers of this journal. Reducing inequalities in health is an important component of UK health policy.

Health and access issues among Australian adolescents: a rural-urban comparison.

INTRODUCTION: Previous research has reported rural-urban differences in health concerns and access issues. However, very little of this has concerned young people, and what has been published has been mainly from countries other than Australia and may not generalise to Australian youth. The study described in this paper is a subset of a larger study on health concerns and access to healthcare for younger people (12-17 years) living in New South Wales (NSW), Australia. This paper reports findings on rural-urban similarities and differences. The specific study objective was to identify and describe rural-urban differences, especially those associated with structural disadvantage. METHOD: The reported findings form part of a larger state-wide cross-sectional study of access to healthcare among NSW adolescents. Adolescents were drawn from high schools in ten of the 17 Area Health Services in NSW. These Area Health Services were selected because they represent most aspects of rural-urban NSW with respect to population characteristics and health services. Eighty-one focus groups were conducted with adolescents (35 with boys and 46 with girls), of which 56 were conducted in urban, 22 in rural and 3 in regional areas. The focus groups were tape-recorded, transcribed and analysed using the computer software package NUD*IST 4. RESULTS: The analysis revealed certain health concerns that were common to both rural and urban adolescents: use of alcohol and illicit drugs, bullying, street safety, diet and body image, sexual health, stress and depression. However, certain concerns were mentioned more frequently in rural areas (eg depression), and two concerns were raised almost exclusively by rural youth (youth suicide and teenage pregnancy). There were also structural differences in service provision: adolescents in rural areas reported disadvantage in obtaining access to healthcare (limited number of providers and lengthy waiting times); having only a limited choice of providers (eg only one female doctor available), and cost (virtually no bulk billing--ie direct charge to Medicare with no patient co-payment). A lack of confidentiality as a barrier to seeking service access was raised by both rural and urban youth, but was a major concern in rural areas. No issues specific to urban areas were raised by urban youth. Male and female rural adolescents were more likely than urban adolescents to express concerns over limited educational, employment and recreational opportunities, which they believed contributed to their risk-taking behaviour. Gender differences were evident for mental health issues, with boys less able to talk with their peers or service providers about stress and depression than girls. These gender differences were evident among adolescents in both rural and urban areas, but the ethos of a self-reliant male who does not ask for help was more evident among rural boys. CONCLUSIONS: While Australian rural and urban youth shared many health concerns, rural-urban differences were striking in the almost exclusive reporting of youth suicide and teenage pregnancy by rural adolescents. The findings suggest that structural disadvantage in rural areas (limited educational, employment opportunities, and recreational facilities) impact adversely on health outcomes, particularly mental health outcomes, and contribute to risk-taking behaviour. Such disadvantages should be considered by health-service policy makers and providers to redress the imbalance. Gender differences were also evident and efforts to target the specific needs of Australian adolescent boys are warranted.

Iron deficiency in Australian-born children of Arabic background in central Sydney.

OBJECTIVES: To determine the prevalence of iron depletion and deficiency, and iron-deficiency anaemia, along with risk factors for iron depletion, in Australian-born children aged 12-36 months of Arabic-speaking background. DESIGN: Community-based survey. SETTING: Central Sydney Area Health Service (CSAHS), NSW, April to August, 1997. PARTICIPANTS: All children born at five Sydney hospitals between 1 May 1994 and 30 April 1996, whose mothers gave an Arabic-speaking country of birth and resided in the area served by the CSAHS. MAIN OUTCOME MEASURES: Full blood count (haemoglobin, mean corpuscular haemoglobin, mean corpuscular volume), plasma ferritin concentration, haemoglobin electrophoresis, potential risk factors for iron depletion. RESULTS: Families of 641 of the 1,161 eligible children were able to be contacted, and 403 agreed to testing (response rate, 62.9% among those contacted). Overall, 6% of children had iron-deficiency anaemia, another 9% were iron deficient without anaemia, and 23% were iron depleted. Multiple logistic regression analysis showed three significant independent risk factors for iron depletion: <37 weeks' gestation (odds ratio [OR], 5.88, P=0.001); mother resident in Australia for less than the median time of 8.5 years (OR, 1.96, P=0.016); and daily intake of >600 mL cows' milk (OR, 3.89, P=<0.001). CONCLUSION: Impaired iron status is common among children of Arabic background, and targeted screening is recommended for this group.

Immunization coverage of Australian-born children of Arabic-speaking background in Central Sydney.

OBJECTIVES: To examine the immunization coverage rates of 12-36-month-old Australian-born children from an Arabic-speaking background in Central Sydney as determined by parental report and documentary evidence. METHODOLOGY: Eligible children were identified by examination of the records of five hospitals. Eligibility criteria were that the mother gave an Arabic speaking country of birth and a Central Sydney post code (as her place of residence) and the child was born between 1 May 1994 and 30 April 1996. Parents of all eligible children were invited to participate, either by a special appointment to answer a structured questionnaire, or by telephone survey. Of the 1157 eligible children identified from hospital birth records, only 641 could be contacted, of whom 584 (91.1%) agreed to participate. Full information on age appropriate immunization rates, as reported by parents and documented in records, could be assessed for 403 children. RESULTS: Parents reported that 97.6% of children were fully immunized. When the child's immunization status could be verified from either the child's personal health record and/or the service provider, the rate of full, age-appropriate immunization was 94.3% (95% confidence intervals 92.0-96.6) compared to a parent-reported rate of 98.0%. General practitioners provided 76.2% of immunizations. CONCLUSION: While a substantial proportion of children identified from birth records could not be contacted, comparisons with census data and other analyses indicate that this sample is likely to be representative of the general population of 12-36-month-old Australian-born children from an Arabic-speaking background. This group appeared to be highly immunized. Further studies examining why the rates for this ethnic group are high in Central Sydney may determine strategies which will enhance immunization rates in other communities.

Serological survey of measles and rubella immunity in Sydney preschool children.

OBJECTIVES: To estimate the prevalence of serological evidence of immunity to measles and rubella in preschool children in central and southern Sydney (NSW, Australia) and the prevalence of immunity in children with either documented or parentally reported immunization. METHODS: Geographical cluster random sampling was used to select children aged between 18 and 60 months to participate in the present study. Standardized interviews obtained information on each child's reported (by parents) immunization status and documentary evidence of immunization was recorded from the Personal Health Record. Venous blood was collected, serum was separated and stored frozen until tested. Measles and rubella antibodies were measured using ELISA, with either immunofluorescence or haemagglutination inhibition being used to clarify equivocal results. The study was conducted from 1992 to 1994 in conjunction with surveys of blood lead concentrations, iron status and micronutrient status. RESULTS: Parents of 726 of 953 children identified between 9 and 60 months of age agreed to participate in the lead, immunization, iron status and micronutrient studies. Sufficient blood for antibody testing was obtained from 580 children, aged 18 to 62 months at the time of collection. Parents reported that 94.7% (95% confidence interval (CI) 92.7-96.5%) of children had received a measles-mumps or measles-mumps-rubella (MMR) immunization. General practitioners administered 72.8% of these immunizations. The prevalence of serological evidence of immunity to measles and rubella was 88.8% (95% CI 86.2-91.4%) and 91.9% (95% CI 89.6-94.2%). respectively. There was documented evidence of measles and rubella immunization for 88.4% (95% CI 85.7-91.2%) and 86.4% (95% CI 83.4-89.3%) of children, respectively. Of children with documented measles immunization, 91.6% (95% CI 89.2-94.0%) had detectable measles antibody. Of children with documented rubella immunization 97.2% (95% CI 95.8-98.6%) had detectable rubella antibody. CONCLUSIONS: Measles and rubella immunization rates in central and southern Sydney are relatively high and most of these immunizations are provided by the private sector. Immunity to rubella in children with documented rubella immunization is at the level that would be expected from seroconversion studies. Immunity to measles in children with documented measles immunization is slightly lower than expected from seroconversion studies, highlighting the need for the second MMR immunization in preschool children, as well as making near universal immunization imperative if this disease is to be eradicated.

Cost effectiveness analysis of school based Mantoux screening for TB infection.

OBJECTIVE: To assess the cost-effectiveness of adding school based Mantoux screening programs to the New South Wales current TB prevention strategy. METHOD: A decision analysis model compared the costs and consequences of screening strategies against the current no-screen strategy. Costs associated with screening and with treating future cases of TB were considered. Consequences considered were deaths and adult cases of TB prevented. The study was based on data from prevalence surveys conducted in 1992 and 1994 in Central and South Western Sydney, New South Wales. Screening strategies considered were screening all or only overseas born (OSB) 6 year olds and all or only OSB 14 year olds in school settings. RESULTS: Screening 14 year olds prevented more deaths and adult cases of TB than screening 6 year olds for a similar cost. For both age groups targeted screening of OSB children was more cost-effective than screening all children. Targeted screening of 14 year olds--the most cost effective option--cost $17,956 (costs and benefits discounted at 5%) per adult case prevented, equivalent to approximately $130,000 per life year saved. The cost-effectiveness ratios decline substantially if lower discount rates and less conservative assumptions are applied. CONCLUSION: Targeted screening was more cost effective than screening all children, however, there are ethical implications of targeting a group based on their origin of birth. IMPLICATIONS: As prevention and control of TB continues to be a high priority for NSW, the implications of a school based screening program should be seriously considered.

Prevalence of tuberculosis infection among homeless young people in central and eastern Sydney.

OBJECTIVE: To determine the prevalence of tuberculosis (TB) infection among homeless young people (aged 12-25 years) in central and eastern Sydney. METHODOLOGY: A cross-sectional survey was conducted in 16 youth refuges and four drop-in centres in Central and Eastern Sydney Health Areas and at the Cellblock Youth Health Centre, Glebe and the Kirketon Road Centre, Darlinghurst, New South Wales (NSW). Participants completed a questionnaire and underwent Mantoux testing. RESULTS: One hundred and forty-one young people completed questionnaires and 139 received a Mantoux test; 112 (80. 6%) had their Mantoux read and 10 (8.9%) were Mantoux positive (95% confidence interval 3.6-14.2). None of the risk factors examined were found to be associated with increased risk for TB infection. CONCLUSIONS: In this sample of homeless young people in central and eastern Sydney, the Mantoux positivity rate appears to be higher than the general population in NSW, but they would not currently be considered a high-risk group for TB infection.

Transmission of tuberculosis from a seven-year-old child in a Sydney school.

OBJECTIVES: To determine whether a 7-year-old child with extrapulmonary and pulmonary tuberculosis (TB) and direct smear positive sputum for acid-fast bacilli was infectious to home and school contacts, and to ascertain potential adult sources of infection for these contacts. METHODS: Contact tracing by Mantoux testing was conducted on 220 children at a primary school and after-school care facility, and 59 selected adults considered potential sources of infection. RESULTS: The participation rate for the children was 98% and 92% for the adults. Mantoux positivity (induration >/= 10 mm, or >/= 15 mm with previous BCG) among children was 13% at the school (anticipated rate 2-3%), 26% among school staff, and 7% among children at the after-school care centre where the index case attended. One exposed adult hospital staff member converted from Mantoux negative to positive. No other cases of TB disease were detected among children or adults tested. CONCLUSION: Although spread of TB from children to others is rare, the findings of this investigation indicate that transmission of TB from a young child to other children and an adult may have occurred, and that sputum testing and contact tracing for sputum smear positive children should be considered.

Compliance with anti-tuberculosis preventive therapy among 6-year-old children.

There are no published data regarding compliance with anti-tuberculosis preventive therapy among children in Australia and limited published data worldwide. This study aimed to determine the compliance rate among 6-year-old children prescribed preventive therapy for tuberculosis infection. A prospective cohort study was conducted on 78, 6-year-old children prescribed antituberculosis preventive therapy. Compliance was measured by compliance with prescribed preventive therapy as reported by parents who were administered questionnaires on completion of the course. In a subsample of 44 children, the proportion of children who complied with scheduled visits to the hospital, and pharmacy records of isoniazid dispensed were used as measures of compliance. Questionnaire data indicated a reported compliance rate for completion of the 6-month course of preventive therapy of 70.5% (55 children). For those 55 who reported completing the full course, 91% reported missing less than 1 tablet per week. In the subsample of 44 children, only 59% attended all follow-up clinic visits, and 54% collected all 6 months of isoniazid prescribed. Compliance with antituberculosis preventive therapy is suboptimal. Improved methods to measure compliance and strategies to optimise compliance with preventive therapy is required.

Opportunistic sampling from early childhood centres: a substitute for random sampling to determine lead and iron status of pre-school children?

This report compares the results from two sampling strategies used to determine the prevalence of elevated blood lead concentrations and iron status in 12-36 month old children in Central Sydney. The two methods were stratified random sampling using census collector districts and an opportunistic sampling strategy using client registers at Early Childhood Centres (ECCs). The response rates were 75.3% (n = 718 of whom 198 were aged 12-36 months) and 24.1% (n = 304) respectively. The geometric mean blood lead concentrations were 0.40 and 0.34 mumol/L respectively (p = 0.001). The traditional random sampling prevalence survey identified a significantly higher proportion of children with blood lead concentrations greater than 0.48 (OR = 0.61, 95% CI 0.40-0.93) and 0.72 mumol/L (OR = 0.44, 95% CI 0.21-0.92) compared to the simpler opportunistic survey. The median plasma ferritin concentration for both studies was 19 micrograms/L (p = 0.4). The prevalence of iron depletion, iron deficiency and iron deficiency anaemia was not significantly different between the two studies. In conclusion, opportunistic sampling through ECCs does not appear to be a substitute for the traditional random sampling prevalence surveys of determine the prevalence of elevated blood lead concentrations in pre-school children in Central Sydney. However, opportunistic sampling through ECCs may be an appropriate method for monitoring iron status, in particular iron depletion, in pre-school children in Central Sydney.

Plasma and serum micronutrient concentrations in preschool children.

The plasma concentrations of vitamin A, vitamin E, beta-carotene and serum concentrations of zinc, retinol-binding protein and prealbumin were examined for a random cluster sample, stratified by socioeconomic status, of 467 healthy preschool children. Children were aged 9-62 months; 44% were females. The mean plasma values were: vitamin A, 1.29 micromol l(-1); vitamin E, 18.9 micromol l(-1); and beta-carotene, 0.30 micromol l(-1). The mean serum values were: zinc, 13.9 micromol l(-1); retinol-binding protein, 25.5 mg l(-1); and prealbumin, 186.2 mg l(-1). The mean molar ratio of vitamin A to retinol-binding protein for the study group was 1.10. There were no differences in the mean values of any of the measured micronutrients between the genders. The results of this survey do not indicate that the prevalence of micronutrient deficiency in this preschool population is of public health significance.

Age-specific reference intervals for plasma vitamins A, E and beta-carotene and for serum zinc, retinol-binding protein and prealbumin for Sydney children aged 9-62 months.

Paediatric reference intervals for blood concentrations of certain nutrients are often based on either adult data or are derived from small samples of young children. Biochemical data were obtained from 467 randomly selected, healthy preschool children aged 9-62 months in Sydney, Australia. Data were obtained for plasma vitamins A, E and beta-carotene and for serum zinc, retinol-binding protein and prealbumin. Reference intervals based on the 2.5 and 97.5 centiles for age groups 9-23, 24-35, 36-47, 48-62 months and for the total group (9-62 months) were calculated. The 2.5-97.5 centiles for the whole group were: vitamin A, 0.7-1.8 mumol/l (20.05-51.56 micrograms/dl); vitamin E, 8-30 mumol/l (0.34-1.29 mg/dl); beta-carotene, 0.1-1.1 mumol/l (5.4-59.0 micrograms/dl); zinc, 9-19 mumol/l (58.8-124.2 micrograms/dl); retinol-binding protein, 14-36 mg/l; prealbumin, 104-264 mg/l. The reference intervals reported are consistent with the findings of a number of smaller studies and are likely to be an accurate reflection of the true intervals for healthy preschool children in western developed countries.

Iron status and anaemia in preschool children in Sydney.

The purpose of this study was to determine the iron status of preschool children in Sydney. We assessed 678 children aged 9 to 62 months living in 32 randomly selected census collection districts in central and southern Sydney for iron status using plasma ferritin; of these 678 children, 542 had zinc protoporphyrin tests, red cell indices and haemoglobin tests. Risk factors for iron deficiency were assessed by an administered questionnaire. Overall, the prevalence of iron depletion was 10.5 per cent, iron deficiency 2.8 per cent and iron deficiency anaemia 1.1 per cent. The 24-to-35-month age group (176 children) had the highest prevalence of iron deficiency anaemia of 3.0 per cent although iron depletion (18.7 per cent) and iron deficiency (5.4 per cent) were highest among the 9-to-23-month age group (182 children). Low iron status was related to age of under 24 months (odds ratio (OR) 2.86,95 per cent confidence interval (CI) 1.72 to 4.76). After adjustment for this age effect, the consumption of red meat fewer than four times a week was significantly associated with iron depletion (OR 2.27, CI 1.25 to 4.17) and there was a tendency for children who were being given a vitamin supplement to be less likely to be iron depleted (OR 4.00, CI 0.95 to 16.67). Iron deficiency and iron deficiency anaemia do not represent a major public health problem in preschool children in Sydney. However, for children in the age range of 12 to 36 months there is scope for interventions to further reduce the prevalence of iron deficiency anaemia.

Haem iron intake in 12-36 month old children depleted in iron: case-control study.

OBJECTIVE: To compare the intakes of haem and non-haem iron in iron depleted and iron replete children. DESIGN: Case-control study. SETTING: Early Childhood Centres and a long day care centre in Sydney, Australia. SUBJECTS: Children aged 12-36 months depleted in iron and controls matched for age and sex. MEAN OUTCOME MEASURES: Iron status by using plasma ferritin concentration. A three day weighed dietary intake record completed by the parents. Risk factors for iron deficiency assessed by questionnaire. RESULTS: Fifty six iron depleted and 68 iron replete children participated. The average daily intake of haem iron was significantly lower in the iron depleted group (t = 2.392, P = 0.018); there was a tendency towards a lower average daily intake of non-haem iron (t = 1.724, P = 0.086) and vitamin C (t = 1.921, P = 0.057) for iron depleted children. Low intake of haem iron (< 0.71 mg/day) was significantly associated with iron depletion with an odds ratio fo 3.0 (P = 0.005). The proportion of iron depleted children who were given whole cows' milk before 12 months of age was almost double that of iron replete children; multivariate analysis showed that both haem iron intake and age of introduction of cows' milk were independently associated with iron depletion. CONCLUSIONS: The results of this study show that, in young children in developed countries, a lower haem iron intake is a major risk factor for iron depletion; the introduction of whole cows' milk before 12 months is further confirmed as a risk factor. Parental education on nutrition should now focus on these two aspects of nutrition for infants and young children.

Prevalence of tuberculosis infection among primary school-entry children in Sydney.

A cross-sectional survey of 2044 Year I children enrolled in 24 primary schools was performed to determine the prevalence of tuberculosis (TB) infection. Of the 2044 children, 1458 (71 per cent) were Mantoux-tested and 1452 Mantoux reactions were read. Of the total, 6.5 per cent were Mantoux-positive; 17.8 per cent of overseas-born children and 2.8 per cent of Australian-born children were Mantoux-positive (relative risk for overseas-born 6.9, 95 per cent confidence interval 4.2 to 9.6). In the areas of Sydney where the study was conducted, there is a high prevalence of TB infection (non-contagious) among overseas-born children in the five- to seven-year age group. This indicates that there may be a large pool of infected children, a proportion of whom are at risk of developing active (contagious) adult-type TB in the future. These data, with other published data on TB infection rates in other age groups, can contribute to the estimation of the size of the infected pool in Australia to allow rational decisions regarding control of TB in Australia, including the possibility of introducing Mantoux screening and preventive therapy programs for high-risk groups.

Blood lead concentrations of preschool children in central and southern Sydney.

OBJECTIVES: To determine the prevalence of elevated blood lead concentrations in preschool children in central and southern Sydney. PARTICIPANTS AND SETTING: Children aged from 9 months to 5 years living in 32 randomly selected geographical areas in Central and southern Sydney. METHODS: Venous blood lead concentrations were estimated by atomic absorption spectrometry. RESULTS: 953 children were identified and 726 had parental consent to participate. A blood sample for lead estimation was obtained from 718 children. The geometric mean blood level concentration was 0.34 mu mol/L (7.0 mu/dL). The proportion of children with elevated blood lead concentrations was: 16.1% (>0.48 mu mol/L [10mu/dL]), 3.9% (>0.72 mu mol/L[15mu/dL]) and 0.3% (>1.21mu mol/L [25 mu/dL], respectively. The blood lead levels for children living with a 10-km radius of the Sydney Central Business district were: 25% (>0.48 mu mol/L [10mu/dL]) and 7% (>0.72 mu mol/L [15mu/dL]), respectively. Corresponding findings for children living 10 km outside this radius were: 9% (>0.48 mu mol/L [10mu/dL]) and 1.5% (0.72 mu mol/L [15mu/dL]), respectively. CONCLUSIONS: The proportion of children with elevated blood lead concentrations in Central and Southern Sydney as a whole does not exceed current National Health and Medical Research Council (NHMRC) recommendations. However, in those areas within a 10-km radius of the Central Business District, NHMRC interventional guidelines for communities where more that 5% of children have blood lead concentrations higher than 0.72 mu mol/L (15 mu/dL) should be applied.