Growth and morbidity in children in the Aboriginal Birth Cohort Study: the urban–remote differential

Objectives: To describe the prevalence of markers of growth, chronic and infectious disease in peripubertal Aboriginal children living in the Darwin Health Region in the “Top End” of the Northern Territory, and to compare prevalence between children living in urban and remote areas. Design: Cross-sectional survey nested in a prospective birth cohort. Subjects: 482 children living in the region who were recruited at birth (Jan 1987 to Mar 1990) and were followed up between 1998 and 2001, when aged 8–14 years. Main outcome measures: Selected parameters of growth and nutrition, infectious disease and potential markers of chronic adult disease were compared between children living at follow-up in suburban situations in Darwin–Palmerston (urban) and those living in rural communities with an Aboriginal council (remote). Results: Remote children were shorter than urban children (mean height, 141.7 v 146.3 cm; P \u3c0.001), lighter (median weight, 30.3 v 37.1 kg; P \u3c0.001) and had lower body mass index (median, 15.3 v 17.9 kg/m2; P \u3c0.001) and haemoglobin level (mean, 125.1 v 130.9 g/L; P \u3c0.001). Some potential markers of adult chronic disease were higher in urban than remote children: systolic blood pressure (mean, 109.6 v 106.2 mmHg; P = 0.004), and levels of total cholesterol (4.3 v 4.0 mmol/L; P \u3c0.001), high-density lipoprotein cholesterol (mean, 1.4 v 1.2 mmol/L; P \u3c0.001) and insulin (median, 7 v 4 mU/L; P = 0.007). Diastolic blood pressure, levels of red cell folate, serum glucose and low-density lipoprotein cholesterol, and urinary albumin–creatinine ratio did not differ by location. The prevalence of visible infections was also higher in remote than urban children (P \u3c0.05). Conclusion: As some markers of health differ between peripubertal Aboriginal children living in urban areas and those in remote areas, results of surveys in remote areas cannot be generalised to urban Aboriginal populations

An Australian Aboriginal birth cohort: a unique resource for a life course study of an Indigenous population. A study protocol

BACKGROUND: The global rise of Type 2 diabetes and its complications has drawn attention to the burden of non-communicable diseases on populations undergoing epidemiological transition. The life course approach of a birth cohort has the potential to increase our understanding of the development of these chronic diseases. In 1987 we sought to establish an Australian Indigenous birth cohort to be used as a resource for descriptive and analytical studies with particular attention on non-communicable diseases. The focus of this report is the methodology of recruiting and following-up an Aboriginal birth cohort of mobile subjects belonging to diverse cultural and language groups living in a large sparsely populated area in the Top End of the Northern Territory of Australia. METHODS: A prospective longitudinal study of Aboriginal singletons born at the Royal Darwin Hospital 1987–1990, with second wave cross-sectional follow-up examination of subjects 1998–2001 in over 70 different locations. A multiphase protocol was used to locate and collect data on 686 subjects with different approaches for urban and rural children. Manual chart audits, faxes to remote communities, death registries and a full time subject locator with past experience of Aboriginal communities were all used. DISCUSSION: The successful recruitment of 686 Indigenous subjects followed up 14 years later with vital status determined for 95% of subjects and examination of 86% shows an Indigenous birth cohort can be established in an environment with geographic, cultural and climatic challenges. The high rates of recruitment and follow up indicate there were effective strategies of follow-up in a supportive population

Intraindividual variation in urinary iodine concentrations: effect of adjustment on population distribution using two and three repeated spot urine collections

Objectives: To determine the effect of adjustment for intraindividual variation on estimations of urinary iodine concentrations (UIC), prevalence of iodine deficiency and population distribution of iodine status. Setting: Community-dwelling older adults from New South Wales, Australia. Participants: 84 healthy men and women aged 60–95 years were recruited prior to introduction of the mandatory iodine fortification programme. Primary and secondary outcome: measures UIC data were collected from three spot urine samples, each 1 week apart. Repeated measures analysis of variance were determined between-person (sb) and total (sobs) SDs. Adjusted UIC values were calculated as ((person\u27s UIC−group mean)×(sb/sobs))+group mean, and a corrected UIC distribution was calculated. Results: The sb/sobs for using three samples and two samples were 0.83 and 0.79, respectively. Following adjustment for intraindividual variation, the proportion with UIC \u3c50 μg/L reduced from 33% to 19%, while the proportion with UIC ≥100 μg/L changed from 21% to 17%. The 95th centile for UIC decreased from 176 to 136 μg/L. Adjustment by taking averages yielded a lesser degree of contraction in the distribution than the analysis of variance method. Conclusions: The addition of information about intraindividual variability has potential for increasing the interpretability of UIC data collected to monitor the iodine status of a population