Energy expenditure,physical exertion and time allocation among Hulispeaking people in the Papua New Guinea Highlands

Objectives: The study aimed to (1) elucidate the energetic adaptations of Huli people by comparing the three sub-populations in relation to their diversified natural and socioeconomic environment, based on energy expenditure and time allocation data; and (2) assess the applicability of a new index of physical exertion levels of activities (physical exertion index: PEI). Research design and methods: Married males and females (n = 43) were selected, including 14 from a hilly village, 13 from a flat swampy village and 16 migrants to a town. Continuous heart rate (HR) monitoring, in conjunction with minute-by-minute observation of activities, was undertaken. Total energy expenditure was assessed by flex-HR method and physical activity level (PAL) was calculated as multiples of basal metabolic rate. Observed activities were divided into 15 categories and the PEI was calculated for each: PEI= (mean HR of a categorized activity)/(flex HR) x 100. Results : No significant difference was found in PAL among the three sub-populations: 1.77, 1.92 and 1.81 for men and 1.78, 1.98 and 1.66 for women in hilly and flat villages, and a town, respectively. The comparison of the two village groups revealed that hilly terrain did not affect substantially the physical intensity of agricultural activities. On the other hand, the town migrants were engaged in sedentary paid jobs and these were less energy consuming than agricultural work. However, the different energy costs between paid jobs and agricultural work were offset by longer work time in the town group than in the two village groups (251 vs 50 or 70 min in males; 258 vs 152 or 138 min in females), resulting in similar PAL in the three groups. Conclusions: Despite contrasting natural and social environments, no significant difference was found in daily physical activity level among the three sub-populations (two villages and a town) of Huli-speaking people in Papua New Guinea Highlands.     

Energy expenditure, physical exertion and time allocation among Huli-speaking people in the Papua New Guinea Highlands

OBJECTIVES: The study aimed to (1) elucidate the energetic adaptations of Huli people by comparing the three sub-populations in relation to their diversified natural and socioeconomic environment, based on energy expenditure and time allocation data; and (2) assess the applicability of a new index of physical exertion levels of activities (physical exertion index: PEI). RESEARCH DESIGN and METHODS: Married males and females (n = 43) were selected, including 14 from a hilly village, 13 from a flat swampy village and 16 migrants to a town. Continuous heart rate (HR) monitoring, in conjunction with minute-by-minute observation of activities, was undertaken. Total energy expenditure was assessed by flex-HR method and physical activity level (PAL) was calculated as multiples of basal metabolic rate. Observed activities were divided into 15 categories and the PEI was calculated for each: PEI = (mean HR of a categorized activity)/(flex HR) x 100. RESULTS: No significant difference was found in PAL among the three sub-populations: 1.77, 1.92 and 1.81 for men and 1.78, 1.98 and 1.66 for women in hilly and flat villages, and a town, respectively. The comparison of the two village groups revealed that hilly terrain did not affect substantially the physical intensity of agricultural activities. On the other hand, the town migrants were engaged in sedentary paid jobs and these were less energy consuming than agricultural work. However, the different energy costs between paid jobs and agricultural work were offset by longer work time in the town group than in the two village groups (251 vs 50 or 70 min in males; 258 vs 152 or 138 min in females), resulting in similar PAL in the three groups. CONCLUSIONS: Despite contrasting natural and social environments, no significant difference was found in daily physical activity level among the three sub-populations (two villages and a town) of Huli-speaking people in Papua New Guinea Highlands.     

Ethnic and environmental factors affecting fetal growth in Papua New Guinea

We studied 738 live singleton births in Papua New Guinea to examine the contribution of ethnic origin and environmental factors to birth weight and gestation. Maternal history, examination and post-partum anthropometry, infant anthropometry and clinical gestational assessment were performed, and placental blood slides and histology were examined. Mothers from Highlands provinces who delivered on the coast had larger babies (mean birthweight 3.34 SD 0.48 kg) than either indigenous coastal mothers (mean 3.10 SD 0.51 kg) or those migrating to Port Moresby from other coastal regions (mean 3.14 SD 0.51 kg). This was due to a combination of longer gestation and better intrauterine growth (assessed by birthweight standard deviation scores). Gestation was slightly longer in Highlands mothers delivering on the coast compared with those delivering in the Highlands, but birthweight standard deviation scores were unchanged. Malarial infection of the placenta was almost never found. Stepwise regression analysis showed that parity, maternal height, Highlands origin and maternal body mass index (weight/height2) were all significant predictors of birthweight standard deviation score, while maternal body mass index and Highlands origin were predictors of gestational length. We conclude that Highland mothers have a tendency to deliver heavier babies, and do not demonstrate the fetal growth-retarding effects of altitude seen in other races. Although the incidence of low birthweight was only 7.1% in our study, we found that indices of maternal nutrition were predictors of birth weight.     

Maternal work and childhood nutritional status among the Purari,Papua New Guinea

In traditional economies, body size, physical work capacity, subsistence productivity, and nutrition of adults may be interrelated, and one cross‐generational effect of these relationships may operate through the household, influencing nutritional status of children. In this analysis, the relationships among adult body size, work productivity in terms of time spent making sago starch, dietary diversity, nutrient availability, and childhood nutritional status are examined in the Purari population of Papua New Guinea, a group largely dependent on the starchy staple palm sago, which is devoid of all nutrients apart from energy. Observations of work scheduling, household food and nutrient availability, and nutritional status were carried out for 16 women, their households, and their children. A multiple regression model of hours spent in sago making on a particular day with days spent in other subsistence activities showed a negative relationship with the number of days spent in sago‐making and a positive relationship with the number of days spent fishing. The number of hours spent in sago‐making on a particular day was also positively related to daily per capita availability of protein at the household level. This is not a function of maternal nutritional status, however, since there is no association between body size of adult females and the number of hours spent making sago on a particular day. Nor does the greater per capita protein availability at the household level in households where women spend longer on a particular day in sago‐making result in improved childhood nutritional status. Since relationships among adult body size, work productivity, dietary diversity, nutrient availability, and childhood nutritional status are only partially demonstrated in this population, it may be that these linkages may only be important if physically arduous work is needed more consistently than is the case in the Purari delta. Am. J. Hum. Biol. 15:472–478, 2003. © 2003 Wiley‐Liss, Inc.     

Fertility and infertility in Papua New Guinea

Fertility levels in selected populations of coastal and highland Madang Province of Papua New Guinea are analyzed from reproductive history data. Changing levels of fertility between 1964 and 1984 are examined using reconstructed censuses. Age-specific infertility rates are calculated and evaluated with available data on rates of sexually transmitted diseases (STD) and contraceptive usage. These suggest that STD-associated infertility may be a major factor underlying levels of fertility lower than expected. © 1993 Wiley-Liss, Inc.     

Secular trend in birthweight among the Purari delta population, Papua New Guinea

The aim of this analysis was to examine the extent and possible seasonal nature of the secular trend in mean birthweight in the Purari delta, Papua New Guinea. This is a country undergoing rapid modernization, and with this has come a secular trend toward increased adult body size in some parts of the country but not others. Birthweight data, collected by month of delivery at Kapuna Hospital in the Purari delta between the years 1969 and 1996, was analysed by year of birth and by season, using one-way analysis of variance and post hoc Scheffé tests with the statistical software SPSS-PC+. A total of 927 birthweights for the years 1969, 1972, 1977, 1994 and 1996 were included in the analysis. Twin births were excluded from analysis, as were births below 1.5 kg. There is clear evidence of a secular trend in increasing mean birthweight between the period 1969 and 1996, with the largest significant difference being between 1977 and 1994, from 2.70 to 2.92 kg. There were no significant differences in mean birthweight between the sexes. The rate of birthweight increase between 1977 and 1994 was 130 g per decade, lower than the gain of 200 g per decade in the period 1994-1996. The decline in birthweight of 90 g per decade during the period 1969-1977 is not statistically significant. The proportion of infants born with low birth weight (< 2.5 kg) shows an increase between 1969 and 1972, and a decline thereafter. While seasonal differences in birthweight during any of the years examined is non-significant, significantly greater mean birthweight across the period 1969-1996 was found for births during the wet season (April to July), and the drier season (August to November), respectively. The secular increase in mean birthweight is likely to be a consequence of the improvements in maternal diet and increased maternal body size that have come with economic modernization. The secular trend of seasonality in mean birthweight among the Purari delta population may be a function of seasonally varied displacement of traditional diet by non-local bought foods, as well as reduced seasonality of maternal workload associated with the processing of the traditional staple food.     

Two decade trends in birth weight and early childhood growth in Papua New Guinea

At present, little is known about patterns of early growth and development in foraging and small-scale horticultural populations. Moreover, still less is known about secular changes in growth in these populations. Data collected in 1967, 1976, and 1989 are presented for birth weight and subsequent growth to 5 years among Au forager-horticulturalists of Papua New Guinea. Despite the launching of health campaigns over the last two decades aimed at bettering the nutritional status of the Au, the data show that average birth weight has remained stable and low at just over 2600 g. Weight- and length-for-age also show no significant changes among traditional Au over the last 20 years, and remain on average, at just below the U.S. 5th percentile. Evidence for the start of a positive secular trend in birth weight and subsequent growth is seen, however, among a small group of Au children residing in households that have a source of wage income. These individuals show an increase of 150 g in birth weight, and over the subsequent 5 years of growth average 93 g heavier and 2.6 cm taller than Au children in traditional households. In addition to providing baseline data on child growth in a forager-horticulturalist society, the findings provide evidence for a secular trend newly underway, and suggest that health promotion campaigns alone without socioeconomic development may be insufficient in effecting change in growth status in rural communities. Am. J. Hum. Biol. 10:483–493, 1998. © 1998 Wiley-Liss, Inc.     

Sexual risk behaviour,marriage and ART: a study of HIV-positive people in Papua New Guinea

Background

The prevention of intimate partner transmission of HIV remains an important component of comprehensive HIV prevention strategies. In this paper we examine the sexual practices of people living with HIV on antiretroviral therapy (ART) in Papua New Guinea (PNG).

Method

In 2008, a total of 374 HIV-positive people over the age of 16 and on ART for more than two weeks were recruited using a non-probability, convenience sampling methodology. This accounted for around 18% of adults on ART at the time. A further 36 people participated in semi-structured interviews. All interviews were thematically analysed using NVivo qualitative data analysis software.

Results

Less than forty per cent (38%) of participants reported having had sexual intercourse in the six months prior to the survey. Marital status was by far the most important factor in determining sexual activity, but consistent condom use during vaginal intercourse with a regular partner was low. Only 46% reported consistent condom use during vaginal intercourse with a regular partner in the last six months, despite 77% of all participants reporting that consistent condom use can prevent HIV transmission. Consistent condom use was lowest amongst married couples and those in seroconcordant relationships. The vast majority (91.8%) of all participants with a regular heterosexual partner had disclosed their status to their partner. Qualitative data reinforced low rates of sexual activity and provided important insights into sexual abstinence and condom use.

Conclusions

Considering the importance of intimate partner transmission of HIV, these results on the sexual practices of people with HIV on ART in PNG suggest that one-dimensional HIV prevention messages focussing solely on condom use fail to account for the current practices and needs of HIV-positive people, especially those who are married and know their partners’ HIV status.

     

Size relationships among permanent mandibular molars in Aboriginal Australians and Papua New Guinea Highlanders.

Size relationships among crown units of permanent mandibular molars were investigated in two Sahul-Pacific samples: Aboriginal Australians (Yuendumu) and Papua New Guinea Highlanders (Wabag). Measurements of first, second, and third molars (M1, M2, and M3), including overall mesiodistal and buccolingual diameters as well as the mesiodistal and buccolingual diameters of the trigonid and talonid, were obtained from dental casts using a sliding caliper. Molar reduction was noted in talonid dimensions within both samples, but the trigonid mesiodistal diameter was not reduced in M2 or M3 compared with M1, indicating that the later-developing crown unit (talonid) was more reduced than the early-developing unit (trigonid). M2 was most reduced in size mesiodistally of the three molars, but its buccolingual diameter was not reduced. M3 was the most reduced tooth in trigonid buccolingual diameter. The percentage sexual dimorphism values were greater for the size of the talonid than for the trigonid, indicating that male values exceeded those for females by a greater amount in the later-developing crown unit. Crown dimensions were larger generally in the Aboriginal Australians from Yuendumu than in the Papua New Guinea Highlanders from Wabag, with differences being more evident in M2 and M3 than M1, especially in talonid dimensions. The trigonid, which develops early both phylogenetically and ontogenetically, tended to be relatively stable in size, whereas the later-forming talonid displayed size reduction when comparisons were made both within and between groups.     

Changes in patterns of growth and nutritional anthropometry in two rural modernizing Papua New Guinea communities

In Papua New Guinea growth is slow and adult body size is small. This is often considered an adaptation to the low energy and nutrient densities of the diets in which tubers and root crops predominate. Social and economic change have been a feature of Papua New Guinea, particularly in recent times. In 1969 the human biology of two contrasting communities, one coastal with a long interaction with external influences and cash cropping, the other a highland community with a history of more recent contacts, was investigated. In 1984 repeat measurements of nutritional anthropometry were made on the villagers and those born in the previous 14 years. The coastal boys and girls were taller and heavier in 1984 compared with 1969 but remained below the 5th percentile of reference North American data. Increases were also found in the highland children, particularly girls, but significantly lower means were found in children under 2 years. Although stunting was less common in the coastal children in 1984, 156 cases (37%) versus 175 cases (43%) (x² = 7·69, ρ < 0·05), wasting increased in prevalence from 11 cases (3%) to 20 cases (5%) (n.s.), either because of recent food shortages or because height change was greater than weight change. Stunting rose by 3% to 53% (165 cases) in highland children (x² = 7·24, p < 0·05). In adults, heights were 2–3 cm greater in 1984 than 1969, and weights 2–3 kg greater, with peak differences in the 30–39-year-olds. The percentage of coastal women with body mass indices of less than 18·5 kg/m² fell from 32% to 15% (x² = 27·4, p < 0·01). Mid-upper arm circumferences and triceps skinfolds were significantly higher in all groups. National and regional data suggest that the communities were better off in 1984 than 1969, but social and economic changes were associated with variable benefits in growth and nutritional status.     

Speciation and distribution of the members of the Anopheles punctulatus (Diptera: Culicidae) group in Papua New Guinea

Mosquito collections were made throughout the mainland of Papua New Guinea to identify the members of the Anopheles punctulatus group present and to determine their distribution. Identification was made using morphology, DNA hybridization, and polymerase chain reaction (PCR)-RFLP analysis. Nine members of the group were identified: An. farauti s.s. Laveran, An. farauti 2, An. koliensis Owen, and An. punctulatus D?nitz, were common and widespread; An. farauti 4 was restricted to the north of the central ranges where it was common; An. farauti 6 was found only in the highlands above 1,000 m; and An. farauti 3, An. sp. near punctulatus and An. clowi Rozeboom & Knight were uncommon and had restricted distributions. Identification of An. koliensis and An. punctulatus using proboscis morphology was found to be unreliable wherever An. farauti 4 occurred. The distribution and dispersal of the members of the An. punctulatus group is discussed in regard to climate, larval habitats, distance from the coast, elevation, and proximity to human habitation.     

Definition of species in the Culex sitiens subgroup (Diptera: Culicidae) from Papua New Guinea and Australia

Japanese encephalitis is a disease of major importance in Asia, which from 1995 has extended its range into the north of Australia. Culex annulirostris Skuse of the Culex sitiens subgroup of Culex was incriminated as the most likely mosquito vector. Because misidentifications previously have occurred within this subgroup, our paper defines electrophoretic methods to identify Culex specimens from Queensland and the Northern Territory in Australia and from Western Province in Papua New Guinea. In collections from 1996 to 1998 Culex sitiens Wiedemann, Cx. palpalis Taylor, and Cx. annulirostris comprised 93.1% of the total banded proboscis Culex mosquitoes collected; 6.9% remained unidentified to species by morphological or electrophoretic examination. The prevalence of Cx. palpalis was variable and appeared to be associated with below average rainfall during 1997. In Papua New Guinea, this species comprised up to 97.4% of banded proboscis Culex, with smaller numbers collected from the Torres Strait Islands and Cape York; none was collected from other Queensland localities. Cx. annulirostris was more prevalent during years of average or above average rainfall and was predominant in most localities, especially in the Torres Strait and Queensland. These data confirmed the problems in separating Cx. sitiens from Cx. palpalis and Cx. annulirostris using morphological characters.     

Dietary and nutrient intakes of 25 Ningerum (New Guinea) adult males at two times of the year

In nutritional studies of traditional societies, it is often assumed that dietary intakes are sufficiently homogeneous for dietary studies of short duration to be adequate for accurate assessment of group nutrient intake. The present study examines this assumption by considering food and nutrient intakes of 25 adult males in rural Papua New Guinea (PNG). Five-day weighed dietary intakes were carried out on each individual twice, with a 6-month interval between measurements. The two measurements corresponded to the times of year when the climate was wet and wetter. Energy intakes, at 167 and 169 kJ/kg body weight, were within the range of values reported by other authors for adult males in PNG. Intakes of protein, thiamin, riboflavin, niacin, and calcium were low, while intakes of iron and vitamins A and C were above WHO (FAO/WHO, 1974) recommended daily allowances. Energy and nutrient intakes did not vary between the two times of year, with two exceptions: vitamin C and iron. Intakes of foods and food types varied between wet and wetter times, however. Within- and between-subject coefficients of variation of intakes of energy and six nutrients were used to calculate sample sizes needed to obtain estimates of group intakes at different levels of reliability and number of days of dietary measurement. This varied with the nutrient under consideration and the time of year. At a given level of reliability, accurate estimates of carbohydrate intake could be obtained with smaller sample sizes and/or number of days of observation than for energy, protein, and vitamin C intakes. Longer periods or larger samples would have been needed for the estimation of group vitamin A, fat, and calcium intakes. © 1992 Wiley-Liss, Inc.     

HLA and tropical splenomegaly syndrome in the Upper Watut Valley of Papua New Guinea

Tropical splenomegaly syndrome (TSS) develops as a result of an atypical immune response to recurrent malarial infection. In general a low prevalence disorder, in the Upper Watut Valley of New Guinea TSS affects more than 80% of the inhabitants. We have studied the association of antigens and haplotypes of HLA-A,B,C, DR, and DQ loci with the severity of TSS as judged by the degree of splenomegaly in 77 unrelated Watut. The study confirmed the previously observed lack of association of TSS with HLA-A and B locus antigens. By contrast, HLA-DR2 was found to be more frequent in patients with gross splenomegaly than in those with moderate splenic enlargement. No two-locus haplotypes were, however, found to be significantly associated with TSS.