Diabetes incidence in an Australian aboriginal population. An 8-year follow-up study.
(17/872)
OBJECTIVE: To examine prospectively the association between age, BMI, and subsequent incidence of type 2 diabetes in Australian aboriginal people. RESEARCH DESIGN AND METHODS: We performed a stratified analysis of incidence data from a community-based longitudinal study. Measures included fasting and 2-h postload glucose concentrations, and BMI, stratified into four categories. Subjects were 882 male and female participants in diabetes screening initiatives in two remote Australian aboriginal communities, free from diabetes at baseline, ages 15-77 years. RESULTS: There were 46 incident cases of diabetes over 2,808 person-years of follow-up. BMI modified strongly the sex- and community-adjusted association between age and diabetes incidence (P < 0.001). Adjusted for age, sex, and community, the population diabetes incidence rate was 20.3 cases/1,000 person-years, with BMI-specific rates of 10.7-47.2 cases/1,000 person-years, and relative risks (95% CI) for BMI strata beyond the reference category (< 25 kg/m2) of 3.3 (1.5-7.0), 2.7 (1.1-6.8), and 4.4 (1.7-11.6), respectively. The population's attributable risk (95% CI) associated with BMI beyond the reference category was 70.1% (58.1-82.4). CONCLUSIONS: BMI-specific diabetes incidence rates in Australian aboriginal people are among the highest in the world. Diabetes incidence in the lowest BMI category (10.7 cases/1,000 person-years) is two to five times greater than corresponding rates for non-aboriginal populations. An urgent need exists to prevent weight gain associated with diabetes. Further study is required to determine for aboriginal people an optimal range of BMI, likely lower than that suggested for non-aboriginal populations. (+info)
Report of a mucopolysaccharidosis occurring in Australian aborigines.
(18/872)
The first 2 reported cases of a mucopolysaccharidosis occurring in an Australian aboriginal family are presented. Though these children had the characteristic morphological features of the Hurler syndrome, enzyme assay of cultured fibroblasts showed normal levels of alpha-L-iduronidase and decreased activity of arylsulphatase B. Thus, they represented the Hurler syndrome clinically, while they had the enzyme defect of the Maroteaux-Lamy syndrome, and they may represent a new severe form of the Maroteaux-Lamy syndrome. The parents of these children were first cousins. Though the children were not full blood aborigines, examination of the pedigree indicates that the gene originated in the common aboriginal family. (+info)
Pharmacokinetics and pharmacodynamics of gliclazide in Caucasians and Australian Aborigines with type 2 diabetes.
(19/872)
AIMS: Gliclazide pharmacokinetics and pharmacodynamics were assessed in 9 Caucasians and 10 Australian Aborigines with uncomplicated type 2 diabetes. METHODS: Subjects were on a stable dose of 80 mg gliclazide twice daily, took 160 mg on the morning of study and had a standard breakfast. No further gliclazide was given over the next 48 h. Regular blood samples were drawn for serum glucose, insulin and gliclazide assay. Gliclazide was measured using h.p.l.c. Noncompartmental analysis was used to describe primary data. A multicompartment model incorporating entero-hepatic recirculation was fitted to group mean serum gliclazide profiles. RESULTS: The Caucasians were older than the Aborigines (mean +/- s.d. age 53.4 +/- 12.2 vs 40.3 +/- 6.9 years, P < 0.05) but had similar diabetes duration, body mass index and glycated haemoglobin. Noncompartmental analysis revealed no between-group differences in gliclazide kinetics. Post-breakfast serum glucose and insulin responses were also similar apart from a longer time to maximum concentration (tmax) for glucose amongst the Aborigines (2.6 +/- 0.4 vs 2.2 +/- 0. 3 h in Caucasians; P = 0.024). Gliclazide tmax exhibited a skewed unimodal distribution and was not associated with gliclazide maximum concentration, or glucose or insulin responses. Most patients had a serum gliclazide profile suggestive of enterohepatic recirculation and/or biphasic absorption. Model-derived estimates of the extent of putative enterohepatic recirculation were 30% and 20% of dose in Caucasians and Aborigines, respectively. CONCLUSIONS: Gliclazide is equally effective in Caucasian and Aboriginal diabetic patients. The pharmacokinetics of oral gliclazide appear more complex than previously thought. Gliclazide pharmacodynamics are unrelated to rate and extent of absorption, consistent with a threshold concentration for hypoglycaemic effect. (+info)
Estimating the prevalence of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, and human papillomavirus infection in indigenous women in northern Australia.
(20/872)
OBJECTIVE: To estimate more accurately the age specific prevalence of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, and human papillomavirus infection (HPV) in indigenous women living in urban, rural, and remote areas of the "Top End" of the Northern Territory (NT). DESIGN: Analysis of data obtained from two community based studies using self administered tampon specimens tested by polymerase chain reaction for sexually transmitted disease (STD). Data pertaining to the notifiable STDs (N gonorrhoeae and C trachomatis) were obtained from the NT health department. PATIENTS: 1090 indigenous women (age range 12-73 years) were enrolled when they attended local community health centres, family planning clinics, and STD clinics. The majority attended clinics in their home community in the course of "well women's checks" which encourage women to undergo screening for a variety of general medical conditions. RESULTS: The overall prevalence of T vaginalis, C trachomatis, N gonorrhoeae, and HPV was 0.25 (95% CI: 0.22-0.28), 0.11 (0.09-0.13), 0.17 (0.15-0.19), and 0.42 (0.37-0.48) respectively. Of the women found to be infected (excluding HPV), 25.5% had two or more of the above organisms detected. There was a statistically significant increase in the age specific prevalence of T vaginalis but a significant decrease with age for C trachomatis and HPV infection. There was no statistically significant change for N gonorrhoeae with age. CONCLUSIONS: STDs are hyperendemic in this population of indigenous women and the notification data significantly underestimate their prevalence. Distinct patterns of age specific prevalence were demonstrated, highlighting the need to tailor control strategies to specific epidemiological features. (+info)
Cumulative incidence of rheumatic fever in an endemic region: a guide to the susceptibility of the population?
(21/872)
Aboriginal Australians in northern Australia are subject to endemic infection with group A streptococci, with correspondingly high rates of acute rheumatic fever and rheumatic heart disease. For 12 communities with good ascertainment, the estimated lifetime cumulative incidence of acute rheumatic fever was approximately 5.7%, whereas over the whole population, with less adequate ascertainment, the cumulative incidence was only 2.7%. The corresponding prevalences of established rheumatic heart disease were substantially less than the cumulative incidences of acute rheumatic fever, at least in part because of poor ascertainment. The cumulative incidence of acute rheumatic fever estimates the proportion of susceptible individuals in endemically exposed populations. Our figures of 2.7-5.7% susceptible are consistent with others in the literature. Such comparisons suggest that the major part of the variation in rheumatic fever incidence between populations is due to differences in streptococcal exposure and treatment, rather than to any difference in (genetic) susceptibility. (+info)
Methods and limits of digital image compression of retinal images for telemedicine.
(22/872)
PURPOSE: To investigate image compression of digital retinal images and the effect of various levels of compression on the quality of the images. METHODS: JPEG (Joint Photographic Experts Group) and Wavelet image compression techniques were applied in five different levels to 11 eyes with subtle retinal abnormalities and to 4 normal eyes. Image quality was assessed by four different methods: calculation of the root mean square (RMS) error between the original and compressed image, determining the level of arteriole branching, identification of retinal abnormalities by experienced observers, and a subjective assessment of overall image quality. To verify the techniques used and findings, a second set of retinal images was assessed by calculation of RMS error and overall image quality. RESULTS: Plots and tabulations of the data as a function of the final image size showed that when the original image size of 1.5 MB was reduced to 29 KB using JPEG compression, there was no serious degradation in quality. The smallest Wavelet compressed images in this study (15 KB) were generally still of acceptable quality. CONCLUSIONS: For situations where digital image transmission time and costs should be minimized, Wavelet image compression to 15 KB is recommended, although there is a slight cost of computational time. Where computational time should be minimized, and to remain compatible with other imaging systems, the use of JPEG compression to 29 KB is an excellent alternative. (+info)
Restricted polymorphism of the mannose-binding lectin gene of indigenous Australians.
(23/872)
Mannose-binding lectin (MBL) is an important complement-activating protein of the human innate immune system. Deficiency of MBL is associated with an increased risk of various infections and arises from three structural gene mutations in exon 1 (variants B, C and D) and/or the presence of a low efficiency promoter. The C allele is found in sub-Saharan Africa whereas the B allele is found elsewhere, suggesting that these mutations occurred after the suggested hominid migration out of Africa [100-150 000 years before present (BP)]. Paradoxically, these alleles may have a selective advantage in protection against intracellular pathogens and occur at particularly high frequencies in sub-Saharan Africa (C variant) and South America (B variant). Since hominids reached Australia at least 50 000 years ago, a study of MBL polymorphisms in the indigenous population was of interest. Using heteroduplex technology we found a paucity of MBL structural gene mutations in two population groups from geographically distinct regions. Of 293 individuals tested, 289 were wild-type and four were heterozygous for either the B or D allele. In each individual with an MBL mutation the HLA haplotype profile suggested some Caucasian admixture. We also found a restricted range of MBL promoter haplotypes and the serum MBL levels were higher than those of any other ethnic group studied to date (median 3.07 microg/ml). Our data suggest that the B mutation probably arose between 50 000 and 20 000 BP. Its absence from the founder gene pool of indigenous Australians may also partly explain their vulnerability to intracellular infections such as tuberculosis. (+info)
A novel ryanodine receptor mutation and genotype-phenotype correlation in a large malignant hyperthermia New Zealand Maori pedigree.
(24/872)
Malignant hyperthermia (MH) is a pharmacogenetic disorder that predisposes to a sometimes fatal hypermetabolic reaction to halogenated anaesthetics. MH is considered to originate from abnormal regulation of skeletal muscle Ca(2+) release. Current diagnosis of MH susceptibility (MHS) relies on in vitro contracture testing (IVCT) of skeletal muscle. The ryanodine receptor (RYR1) encoding the major Ca(2+) release channel in the skeletal muscle sarcoplasmic reticulum has been shown to be mutated in a number of MH pedigrees. The large Maori pedigree reported here is the largest MHS pedigree investigated to date and comprises five probands who experienced clinical episodes of MH and 130 members diagnosed by the IVCT. Sequencing of the 15 117 bp RYR1 cDNA in a MHS individual from this pedigree identified a novel C14477T transition that results in a Thr4826 to Ile substitution in the C-terminal region/transmembrane loop of the skeletal muscle ryanodine receptor. This is the first mutation in the RyR1 C-terminal region associated solely with MHS. Although linkage analysis showed strong linkage (max LOD, 11.103 at theta = 0.133) between the mutation and MHS in the pedigree using the standardized European IVCT phenotyping protocol, 22 MHS recombinants were observed. The relationship between the IVCT response and genotype was explored and showed that as IVCT diagnostic cut-off points were made increasingly stringent, the number of MHS discordants decreased with complete concordance between the presence or absence of the C14477T mutation and MHS and MH normal phenotypes, respectively, using a cut-off of 1.2 g tension at 2.0 mM caffeine and 1.8 g tension at 2.0% halothane. Many MHS pedigrees investigated have been excluded from linkage to the RYR1 gene on the basis of a small number of recombinants; however, the linkage analysis reported here suggests that other recombinant families excluded from linkage to the RYR1 gene may actually demonstrate linkage as the number of members tested within the pedigrees increases. The high number of discordants observed using the standardized diagnostic cut-off points is likely to reflect the presence of a second MHS susceptibility locus in the pedigree. (+info)