Relationship between maternal glycaemia and birth weight in glucose-tolerant women from different ethnic groups in New Zealand.

AIM: The aim of this study was to compare the population attributable fraction(PAF) for a large baby (> or =4 kg) due to glycaemia, weight and smoking in glucose-tolerant women from different ethnic groups. METHODS: A retrospective review of screening for gestational diabetes (GDM)and associated birth weight was undertaken in New Zealand European (n= 529), Maori (n= 540) and Pacific (n= 916) women. The proportion with a large baby was compared by 1-h post 50-g glucose challenge test tertile and maternal weight tertile. RESULTS: Large babies were more common from Pacific and European than Maori women (24.3%, 18.8%, 8.9%, respectively; P<0.001). Birth weight increased significantly with increasing glucose among Pacific women (P<0.001) even after adjusting for maternal weight and other confounders. The risk of having a large baby was 2.56 (1.82-3.60)-fold greater in women in the highest maternal weight tertile (> or =84 kg), with a significantly greater PAF in Pacific women(27.2%, 12.9%, 16.4%, respectively; P<0.001). The odds ratio (OR) of having a large baby increased with even mildly elevated maternal 1-h glucose concentrations [OR for 5.6-6.2 mmol/l: 1.54 (1.11-2.14); for > or =6.3 mmol/l: 2.06 (1.50-2.82)], with no ethnic differences in PAF (11.1-11.8%, 16.7-18.7%, respectively). Smoking and being Maori were associated with smaller babies. CONCLUSIONS: Increased maternal weight and glycaemia are associated with a greater proportion of large babies among glucose-tolerant women. Growth of Pacific babies may be more sensitive to a higher maternal glucose when the mother is obese.     

Population study of T cell receptor V beta gene usage in peripheral blood lymphocytes: differences in ethnic groups.

The T cell receptor (TCR) V beta repertoire in peripheral blood lymphocytes (PBL) of a large number of healthy individuals was analysed by quantifying V beta-specific mRNA using the method of anchored multiprimer DNA amplification and a reverse dot blot assay. Among 16 V beta gene families examined, particular V beta genes were noted to be unequally expressed in the PBL of 70 healthy donors. The frequently used genes belong to the V beta 4, 5, 6, 8 and 13 (12) families, while V beta 1, 9 and 15 were the least frequently used gene families. This bias in gene usage was observed in all individuals. Marked deviation from the mean percentage usage was noted for some V beta genes in individuals when their PBL were examined serially, but the common pattern of biased usage was not grossly distorted. When the TCR repertoire of different ethnic groups was examined, a lower mean frequency of V beta 3.2 was seen in the repertoire of 19 Caucasians compared with 25 age-matched Samoans (P < 0.003). Conversely, the expression of V beta 5.1 and V beta 5.3 was higher in Caucasians than in 51 age-matched Polynesians (Maoris and Samoans, P < 0.003). Considering the 20% co-efficient of variation in the estimate of V beta gene usage, our data from 70 unrelated individuals suggest that in PBL, individual variations in the TCR repertoire were superimposed upon a common biased usage of V beta genes in the general population.     

Empirical support for the reliability of DNA evidence interpretation in Australia and New Zealand

The results of empirical testing of forensic DNA probabilities for Australian and New Zealand populations is reported. It is concluded that if consideration is given to relatedness and subpopulation effects, the current model used in most of Australia and New Zealand appears to give very good predictions.     

Polynesians: prone to obesity and Type 2 diabetes mellitus but not hyperinsulinaemia.

AIMS: To compare the extent of hyperinsulinaemia among New Zealand Europeans and Polynesians (an ethnic group at high risk of Type 2 diabetes mellitus). METHODS: A cross-sectional survey from randomly selected households was conducted in inner urban South Auckland. Subjects were either European, Maori or Pacific Islands Polynesians aged 40-79 years and were screened for diabetes using a random blood glucose. Those with an elevated result, and 20% randomly selected from those with a normal screening result, were invited to a 75-g glucose tolerance test. WHO criteria (1998) for diabetes were used. RESULTS: In those aged 40-59 years, total prevalence of diabetes was 7.5 (6.2-9.0)% in Europeans but 21.1 (16.6-25.6)% among Maori and 25.0 (19.8-30.1)% among Pacific peoples; obesity (body mass index >or= 31.0 kg/m2) was present in 26% Europeans, 63% Maori and 69% Pacific peoples. Non-diabetic Polynesians were relatively hyperglycaemic and hyperinsulinaemic. After adjusting for the degree of obesity, Polynesians had similar insulin levels to Europeans. CONCLUSIONS: These findings indicate that Polynesians are not intrinsically insulin resistant as a group, a prerequisite found in most other ethnic groups at high risk of Type 2 diabetes mellitus. The high prevalence of Type 2 diabetes in Polynesians could be the result of their high prevalence of obesity.     

Molecular genetic studies of natives on Easter Island: evidence of an early European and Amerindian contribution to the Polynesian gene pool

Most archaeological and linguistic evidence suggest a Polynesian origin of the population of Easter Island (Rapanui), and this view has been supported by the identification of Polynesian mitochondrial DNA (mtDNA) polymorphisms in prehistoric skeletal remains. However, some evidence of an early South American contact also exists (the sweet potato, bottle gourd etc.), but genetic studies have so far failed to show an early Amerindian contribution to the gene pool on Easter Island. To address this issue, we analyzed mtDNA and Y chromosome markers and performed high-resolution human leukocyte antigen (HLA) genotyping of DNA harvested from previously collected sera of 48 reputedly nonadmixed native Easter Islanders. All individuals carried mtDNA types and HLA alleles previously found in Polynesia, and most men carried Y chromosome markers of Polynesian origin, providing further evidence of a Polynesian origin of the population of Easter Island. A few individuals carried HLA alleles and/or Y chromosome markers of European origin. More interestingly, some individuals carried the HLA alleles A*0212 and B*3905, which are of typical Amerindian origin. The genealogy of some of the individuals carrying these non-Polynesian HLA alleles and their haplotypic backgrounds suggest an introduction into Easter Island in the early 1800s, or earlier. Thus, there may have been an early European and Amerindian contribution to the Polynesian gene pool of Easter Island.     

FTO polymorphisms in oceanic populations

It has been suggested that Neel’s “thrifty genotype” model may account for high body weights in some Oceanic populations, which presumably arose in modern times. In European populations, common variants (rs1421085-C, rs17817449-G, and rs9939609-A) in the fat mass and obesity (FTO associated) were recently found to be associated with body mass index (BMI) or obesity. In this study, we investigated the population frequencies of these variants in six Oceanic populations (Melanesians, Micronesians, and Polynesians) and tested for an association with BMI. Unlike European populations, the Oceanic populations displayed no significant association between the FTO polymorphisms and BMI. These variants were in strong linkage disequilibrium. The population frequencies ranged between 4.2 and 30.3% in the six Oceanic populations, and were similar to those in southeast and east Asian populations. Our study of the FTO polymorphisms has generated no evidence to support the thrifty genotype hypothesis for Oceanic populations.     

Health and functional status of the elderly in a Polynesian population

A health survey was conducted on a random sample of the elderly living on Niue Island in the Southwest Pacific, an island experiencing both the demographic and epidemiological transitions predicted to become common throughout the Third World in the next decades. One-quarter of the respondents reported having no medical impairments and one-third experience no diminution in functional capacity. Visual and auditory losses were common as were respiratory conditions and chronic degenerative disorders. Mobility was a central aspect of functional status. Few striking differences in health and functional status exist between Niuean elderly and their counterparts in the United States. The small but significant proportion (16%) of Niuean elderly who are very frail represent a challenge to the organization and delivery of current health and welfare services.     

“Food Is Our Love Language”: Using Talanoa to Conceptualize Food Security for the Māori and Pasifika Diaspora in South-East Queensland,Australia

Queensland is home to the largest diaspora of Māori and Pasifika peoples in Australia. They form an understudied population concerning experiences and challenges of food insecurity. This community co-designed research aims to explore the conceptualization of household food security by Māori and Pasifika peoples living in south-east Queensland. Participatory action research and talanoa were used to collect and analyse forty interviews with leaders representing 22 Māori and Pasifika cultural identities in south-east Queensland. Eight key themes emerged that conceptualise food security as an integral part of the culture and holistic health. These themes included: spirituality, identity, hospitality and reciprocity, stigma and shame, expectations and obligations, physical and mental health and barriers and solutions. Addressing food insecurity for collectivist cultures such as Māori and Pasifika peoples requires embracing food sovereignty approaches for improved food security through the co-design of practical solutions that impact social determinants and strengthen existing networks to produce and distribute affordable and nutritious food.     

Early Lapita skeletons from Vanuatu show Polynesian craniofacial shape: Implications for Remote Oceanic settlement and Lapita origins

With a cultural and linguistic origin in Island Southeast Asia the Lapita expansion is thought to have led ultimately to the Polynesian settlement of the east Polynesian region after a time of mixing/integration in north Melanesia and a nearly 2,000-y pause in West Polynesia. One of the major achievements of recent Lapita research in Vanuatu has been the discovery of the oldest cemetery found so far in the Pacific at Teouma on the south coast of Efate Island, opening up new prospects for the biological definition of the early settlers of the archipelago and of Remote Oceania in general. Using craniometric evidence from the skeletons in conjunction with archaeological data, we discuss here four debated issues: the Lapita–Asian connection, the degree of admixture, the Lapita–Polynesian connection, and the question of secondary population movement into Remote Oceania.The first human settlement of Vanuatu is indicated by the Lapita culture, whose earliest signature appears in the northwestern Melanesian islands toward the end of the interval 3,470–3,250 y B.P. or slightly later (1). The Lapita culture is defined by a set of artifacts including highly decorated pottery displaying a distinctive design system, long-distance exchanges of raw material and finished items, translocations of plants and animals, and the initial incursion of humans into the pristine island environments of Remote Oceania to the east of the main Solomon chain between 3,000 and 2,800 y B.P. (1, 2). In Vanuatu, as in the rest of Remote Oceania, Lapita quickly evolved, within 200–300 y, into distinctive local cultures in conjunction with increased population size and sedentism by the end of the Lapita period (3).The question of the biological nature of the Lapita populations is routinely approached with data collected from protohistoric/historic or extant populations used as proxies. Analysis of skull morphology and morphometrics of protohistoric/historic populations from Oceania shows a geographical pattern of variation, separating northern and southern Melanesia from western and eastern Polynesia (4–6). More generally, the results indicate two contrasting divisions, an Australo-Melanesian pole comprising groups from the western part of Remote Oceania (Island Melanesia) and an Asian pole including groups from the (far) eastern part of Remote Oceania (Polynesia). This pattern suggests separate origins for the indigenous inhabitants of these two regions. Evidence from inherited genetic markers indicates that the populations living today in Vanuatu and generally in the region first settled by Lapita groups share a common origin in an area that encompasses Island South East Asia, the north coast of New Guinea, and the Bismarck Archipelago (7–13). These populations display haplogroups attributed both to the Pleistocene settlement of the northern Melanesian/Near Oceanic region and to the Lapita diaspora, with chronological estimates based on genetic data. Geographical variations in haplotype frequencies distinguish the western part of the initial Lapita region from the eastern part, with a smaller diversity in the eastern populations in what is today Western Polynesia.Studies on Lapita skeletal morphology (14–20). In a recent biodistance study of mandibles from Watom (New Britain), Pietrusewsky et al. (16) conclude that “expectation that skeletons associated with the Lapita Cultural Complex, Early or Late Lapita, biologically resemble the modern-day inhabitants of Remote Oceania is not supported” and challenge “the prevailing orthodox view that the origin of Polynesians is associated with Lapita culture.” However, whether the few analyzed individuals represent initial “Lapita people” is open to question. Because they postdate the initial appearance of the Lapita culture in the region (20), they may actually reflect subsequent gene flow and migratory events within the Melanesian region, saying more “about the contemporary indigenous inhabitants of eastern Melanesia than … about the ancestors of the Polynesians,” as noted by Pietrusewsky et al. (18). Alternatively, the possibility that these late Lapita and (immediately) post-Lapita individuals derive directly from the initial “Lapita population” is not excluded, because heterogeneity among the early populations of the region and among the Lapita groups themselves might be expected (21–23).

Table S1.

List of Lapita specimens known so far