The dietary intake of chemical residues in Brisbane adults.

The purpose of this work was to integrate existing chemical residue and food consumption data for individuals to improve estimates of the dietary intake of chemical residues in the population of Brisbane. Previous estimates of intakes from the Australian Market Basket Survey (AMBS) have been based on energy-adjusted 'hypothetical national diets' and so allow no assessment of variation in intakes between individuals or groups. Data on concentration of fenitrothion, chlorpyrifos-methyl, pirimiphos-methyl, heptachlor and dieldrin in selected foods were taken from reports of the AMBS. Food consumption data were based upon the National Dietary Survey of Adults (NDSA) 1983; the same data from which the hypothetical diets are derived. The distribution of estimated 24-hour intakes was adjusted to represent usual intakes. Mean intakes of all residues were about one third those reported previously. None of the observed diets contained levels of residues that were greater than the Acceptable Daily Intakes. These findings support reassurances to the public that residues of agricultural chemicals monitored in the AMBS do not pose a health risk.

The food-service industry, dietary guidelines and change.

The influence of the food-service industry on compliance with the Australian dietary guidelines was investigated through three separate methods of data collection and analysis: a telephone survey of 1683 randomly selected Brisbane residents; telephone interviews with 69 food-service-industry operators and 10 face-to-face interviews with key stakeholders in industry and government. Nearly 40 per cent of respondents had consumed foods prepared by the food-service industry at least once on the day before the interview, mainly from restaurants, cafes and takeaway shops, in the form of fast-food or snacks. Consumption of these foods declined with age. Those consuming foods prepared by the food-service industry ate significantly less fruit, vegetables and dairy food and were therefore less likely to comply with the dietary guidelines. Outcomes from interviews with operators in the food-service industry show that food choices offered to consumers were the result of a dynamic interaction between consumer demand and operators' own tastes and perceptions of food quality. Key informant interviews show that public health nutrition programs will have limited effect without supportive environmental changes in the food-service industry supply. An effective means of increasing the likelihood of compliance with the Australian dietary guidelines will be to encourage food suppliers in ways that address their core business concerns simultaneously with the goals of health professionals.

The implications of underreporting in dietary studies.

Dietary data from the Western Sydney Dietary Survey 1989-90 (n = 512) was used to investigate: 1. the prevalence and predictors of underreporting of energy intake, 2. the effects on results of excluding data from underreporters for analysis of mean nutrient intakes, and 3. the proportion of energy intake supplied by macronutrients and proportions of subjects who met dietary goals. The proportion whose measured energy intakes from a Food Frequency Questionnaire (FFQ) were below cutpoints for biologic plausibility was 28.5 per cent; it was higher for subjects who had BMI > 25 and were female. Point estimates for mean intakes of energy and nutrients were all greater when data from underreporters were excluded, but nutrient intakes expressed as percentages of energy intake remained largely unchanged. Increases in estimated mean population intake for each nutrient ranged from 7 per cent to 14 per cent for males, and 12 per cent to 17 per cent for females. Estimates of the percentages of the sample who did not meet dietary goals were significantly lower for a number of nutrients when underreporters were excluded. We conclude that: 1. results expressed as a percentage of energy intake are not affected by the exclusion of energy underreporters, and 2. estimates of the proportion of populations meeting some nutrient goals and associations between diet and disease are likely to change meaningfully and significantly with the exclusion of data from underreporters.

Endemic goitre and cretinism in the Simbai and Tep-Tep areas of Madang Province, Papua New Guinea.

In the late 1960s and early 1970s a mass campaign of iodized oil injections was carried out in Papua New Guinea as an interim measure to improve iodine status in the population and to prevent endemic goitre and endemic cretinism. Following informal reports of children with neurological abnormalities resembling endemic cretinism in two areas of Madang Province, the Simbai and Tep-Tep Subdistricts, surveys were conducted in these areas in 1985 to establish prevalence rates of goitre and cretinism in order to determine whether they had returned as public health problems. 42% of the Simbai population and 38% of the Tep-Tep population attended for examination. Amongst those surveyed, the visible goitre rate was low: 0.1% in the Simbai and 2.5% in the Tep-Tep area. Although the iodized oil patrols were carried out a decade previously, goitre does not seem to have re-emerged in the area to the levels reported previously. In the Simbai villages surveyed, there were nine individuals diagnosed as suffering from cretinism, three of whom were thought to have been born after the last iodized oil patrol in the area. In the Tep-Tep villages, eight subjects were diagnosed as suffering from cretinism, all of whom were thought to have been born before the iodized oil patrols. A number of younger children with neurological abnormalities which did not fulfil criteria for endemic cretinism were also seen in both areas. Because of the difficulties in diagnosing endemic cretinism in young children, it is not possible to conclude that endemic cretinism is no longer a problem in these areas. More work is needed to confirm the results of these studies. This will enable a rational control program to be designed and implemented.

Nutrition and health in South-East Asia.

Poor nutrition remains a significant contributor to morbidity and mortality in South-East Asia. Manifestations of this include protein-energy malnutrition, iodine deficiency diseases, vitamin A deficiency, iron deficiency and some non-communicable diseases of adults. The extent of these diseases, and their interactions with infection, make nutrition the single most important modifiable host factor underlying health status in the region. It is vital that long-term sustainable programs for the control of nutrition problems are accorded a high priority within the health sector.

Chemoprophylaxis against malaria in Papua New Guinea: a trial of amodiaquine and a combination of dapsone and pyrimethamine.

A placebo-controlled chemoprophylaxis trial was carried out in 1980 in 318 semi-immune school children in the Madang area of Papua New Guinea, where there was a high prevalence of strains of Plasmodium falciparum resistant to 4-aminoquinolines. Since prophylaxis with amodiaquine at 5 mg/kg weekly had failed, amodiaquine at a dose of 10mg/kg weekly and Maloprim (half a tablet or one tablet depending on body weight, which gave ranges of dapsone of 1.7-3.3mg/kg and pyrimethamine 0.2-0.4 mg/kg) weekly were tried. Neither regimen was completely successful in preventing parasitaemia, though after 13 weeks of prophylaxis the slide positivity rate was 16% for the amodiaquine group and 2% for the Maloprim group, which was in each case significantly lower than the normal baseline rate in the controls of 42%. Amodiaquine was completely successful in suppressing Plasmodium vivax infections. Breakthrough parasitaemia occurred, with either P. falciparum or P. vivax, in 5% of subjects on Maloprim at some time during the 13-week period of prophylaxis. Significantly more children in both the amodiaquine and Maloprim groups than in the placebo group showed a reduction in spleen size. All groups showed an unexplained fall in haemoglobin level over the study period but the fall was significantly less in both the prophylaxis groups. There was no adverse effect on white cell counts by either drug regimen. Chemoprophylaxis as a component of an integrated malaria control program should not be overlooked, provided that compliance can be maintained. However, in this particular case the principal purpose of the study had been to evaluate the proposed chemoprophylactic regimens in school children before embarking on an intervention study in young children. As a result of this study it was decided not to go ahead with the chemoprophylactic intervention in young children but to adopt an approach based on early presumptive treatment.

Motor development and nutritional status of young children in Madang, Papua New Guinea.

The relationship between nutritional status and motor development was investigated in a cross-sectional study of 457 0-2 year old children in Madang, Papua New Guinea. The median ages at which the major motor developmental milestones are attained are almost comparable to western populations up to 6 months of age. However, crawling and independent walking are slower to develop. At any given age children of higher nutritional status by weight for age (W/A), length for age (L/A) or weight for length (W/L) are more likely to have attained a given developmental stage than children of lower nutritional status.

Mortality in a rural area of Madang Province, Papua New Guinea.

As part of a multi-disciplinary research programme undertaken by the Papua New Guinea Institute of Medical Research near the town of Madang, northern PNG, a three-year study of mortality was conducted in a rural population of approximately 16,500 people. From early 1982 the area was under continuous demographic surveillance which continued for the three years of the study. All deaths which occurred in this period were investigated by interviewing relatives of the deceased and examining any available health service records. Respiratory diseases were the commonest cause of death, with pneumonia accounting for 20% of deaths in children under 10 years of age, and pneumonia and chronic obstructive lung disease (COLD) together accounting for a third of all deaths. Deaths from COLD were more common in the study population than in PNG hospitals and health centres. The proportion of deaths caused by malaria in children under 10 years was estimated to be between 4 and 17%. Mortality rate in the first year of life were determined by following up a cohort of 1015 births occurring in the first 20 months of the study. Of the 1002 live births, 46 died in the first 12 months of life, giving an infant mortality rate of 45.9% live births. Other mortality and demographic rates were consistent with data reported from the 1980 PNG National Census, suggesting that the study population belonged to an advantaged rural area. Demographic features found in this population were a high birth rate, a relatively low crude death rate, and a rate of natural population increase of 2.8% per annum. The methodological difficulties associated with the measurement of malaria mortality have important implications for the evaluation of future malaria vaccines. The methods employed in this study are critically discussed, and recommendations made for future studies.

The effect of iron therapy on malarial infection in Papua New Guinean schoolchildren.

The effect of iron therapy on malarial infection was investigated in Papua New Guinea, where malaria is endemic. Prepubescent schoolchildren with hemoglobin levels of 8-12 g/dl were randomly assigned to receive either 200 mg ferrous sulfate or a placebo twice daily for 16 weeks. Iron status and malarial infection were assessed at baseline, after 6 and 16 weeks of therapy, and 8 weeks after therapy was discontinued. Iron status was significantly improved by the treatment. The treatment did not significantly affect parasite rate, parasite density, or levels of anti-malarial IgG. No changes in spleen size were observed in either group. Furthermore, there was no significant difference between the groups in reported episodes of suspected malaria during the therapy. These results suggest that, in malaria endemic areas, oral treatment for iron deficiency can be carried out in semi-immune or immune schoolchildren without adverse consequences.

Effects of low protein intake on protein metabolism of Papua New Guinea highlanders studied with [15N]glycine.

The effects of low protein intake on protein metabolism, including the size of pools and the protein synthesis rates, were studied by use of [15N]glycine in Papua New Guinea highlanders. Studies were made on 9 men between October and December in 1982. In experiment 1, two subjects were given a protein-free diet (PFD) containing 49.1 kcal/kg of energy. In experiment 2, subjects were given a sweet-potato diet (SPD) containing 45.4 kcal/kg of energy and 0.507 g/kg of protein for 8 days, and then were given a low-protein sweet-potato diet (LPSPD) containing 50.0 kcal/kg of energy and 0.265 g/kg of protein. During the SPD period, the sizes of the metabolic and active protein pools (mean +/- SD) were 270 +/- 134 mgN/kg and 362 +/- 107 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 463 +/- 161 mgN/kg/day and 299 +/- 38 mgN/kg/day, respectively. During the LPSPD period, the sizes of the metabolic pool and active protein pool were 131 +/- 64 mgN/kg and 378 +/- 106 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 490 +/- 206 mgN/kg/day and 280 +/- 26 mgN/kg/day, respectively. The protein metabolism in the LPSPD showed no significant difference from the SPD. The results suggest that, when the energy levels were approximately the same, protein metabolism in Papua New Guinea highlanders was maintained in spite of the decrease in protein intake.

Human malaria transmission studies in the Anopheles punctulatus complex in Papua New Guinea: sporozoite rates, inoculation rates, and sporozoite densities.

Malaria sporozoite rates and inoculation rates were measured over periods up to 25 months in the different anopheline species biting humans in 13 villages in Madang Province, Papua New Guinea. Analysis of three members of the Anopheles punctulatus complex, 68,458 An. farauti, 36,779 An. koliensis, and 11,667 An. punctulatus caught in landing catches was made using monoclonal antibody based ELISAs to detect sporozoites of Plasmodium falciparum and P. vivax. Sporozoite rates ranged from 0%-5.5% in An. farauti, 0.2%-3.8% in An. koliensis, and 0%-3.3% in An. punctulatus. In addition, over 3,000 An. longirostris were analyzed and sporozoites were not detected in this species. No significant differences were observed between the three vector species in the densities of P. falciparum sporozoites (geometric mean 2,320). However, the geometric mean P. vivax sporozoite density was significantly higher in An. punctulatus (350) than in either An. koliensis (160) or An. farauti (150). An. koliensis was less susceptible to infections of P. falciparum or P. vivax than either An. farauti or An. punctulatus. Variations in average sporozoite and inoculation rates were found among different villages, despite their close geographic proximity. Sporozoite and inoculation rates varied greatly within a village over time, but malaria transmission was perennial with a higher transmission during the wet season by An. koliensis and An. punctulatus.

Longitudinal measurements of breast milk output by a 2H2O tracer technique in rural Papua New Guinean women.

Longitudinal measurements of breast milk output were made using a 2H2O tracer technique over 24 months in 23 rural Papua New Guinean women. A small (n = 14) cross-sectional sample of women from a different area were also studied. Mean outputs of the longitudinal sample rose from 601 +/- 100 g/d at 1 month to a maximum of 901 +/- 211 g/d at 9 months and fell to 501 +/- 188 g/d at 24 months, values which are considerably higher than previously reported from Papua New Guinea. This is considered to be primarily due to the suitability of the method of measurement. The late and complementary nature of the introduction of additional foods to the infant diet is considered to be responsible for the maintenance of these high outputs over periods of up to 24 months in some cases. Multiple regression analysis performed on all data points up to 6 months or 6 kg infant weight showed that infant weight accounted for 55.8 per cent of the total variation in milk output. The additional effect of infant age, given weight, was not significant (t = 1.37). In cross-cultural comparisons infant size was also shown to be a more important determinant of milk output than infant age. These comparisons were made using the rate constant Fbm/Vb, the basic measurement of the estimation of milk output by the tracer method.

The epidemiology of malaria in a population surrounding Madang, Papua New Guinea.

Malaria is prevalent throughout coastal and lowland Papua New Guinea. Recent changes, including a shift from predominance of Plasmodium vivax to Plasmodium falciparum, appearance of chloroquine-resistant P. falciparum and decreased effectiveness of vector control programs have been observed. Epidemiological features of malaria were studied through four six-month surveys of a population of 16,500 in Madang Province from 1981-1983. Baseline data on parasitology, splenic enlargement, serology, hemoglobin levels, prevalence of 4-aminoquinolines, utilization of mosquito nets and incidence of fever were collected for use in future evaluation of malaria control measures including possible field trials of an antimalarial vaccine. Prevalence of parasitemia (all species, all ages) varied from 35.0% to 42.7% over the four surveys each of which covered a random sample of 25% of the population. The ratio of parasite species was: P. falciparum 70:P. vivax 25:P. malariae 5 in the dry seasons, shifting slightly in favor of P. falciparum during the wet seasons. Intense year-round transmission was indicated by decreasing parasite prevalence and splenic enlargement with age, low density asymptomatic parasitemias and high prevalence of antimalarial antibodies (i.e., greater than 80% of the population over five years of age was ELISA-positive). Levels of endemicity varied geographically, presence of 4-aminoquinolines in urine samples was relatively common (12.7% positive) and chloroquine resistance was widespread (81.6% in vitro, 46.6% in vivo).

The role of voluntary village aides in the control of malaria by presumptive treatment of fever. 1. Selection, training and practice.

As part of a multi-disciplinary malaria research programme in a rural area of Madang Province, the Papua New Guinea Institute of Medical Research (PNG IMR) in 1982 established a village-based intervention programme of presumptive treatment of fever in 35 villages (population about 5,200). Seventy-four villages aides, selected by people from their own village, attended two-week training courses conducted by PNG IMR staff, and were trained to dispense three-day courses of amodiaquine (for children) or chloroquine (for adults) to anyone presenting with fever (presumptive malaria). The majority of village aides, who were voluntary workers, were married men and women between the ages of 20 and 35 years, who had had up to six years' schooling. In 1983, 5,075 fever cases were treated by village aides, which represents a quarter of the number of fever episodes estimated to occur each year in this area. Utilization of village-aide services was variable, the most important determining factors being the personality and standing of the village aide, and the distance (walking time) to the village aide's house from the patient's house. The village aides' role was expanded to include taking blood slides, dispensing other medicines (aspirin and dressings), treatment of diarrhoea by oral rehydration, and registration of vital demographic events in the village. Regular supervision, currently undertaken on a two-weekly basis by PNG IMR staff, regular refresher courses, and, probably, some sort of compensation (not necessarily monetary) are important for the long-term continuation of the programme, which may serve as a model for other areas.(ABSTRACT TRUNCATED AT 250 WORDS)