Biomedical subjects

Stanley J Ulijaszek

Publications and source records attributed to Stanley J Ulijaszek.

8 recordsLinked to original sources

PubMed2004

Intra-individual variation in RMR in older people.

In the factorial estimation of total energy expenditure it is assumed that the intra-individual variation in RMR is small. Little is known about the intra-individual variation in RMR in older subjects. The present study investigated the intra-individual variation in RMR in older people. Measurements of RMR were made in twenty-seven older subjects, mean age 71.6 (sd 6.1) years, on two separate occasions (T1 and T2) and on a third occasion (T3) in nineteen of the subjects. Measurements of height and weight were taken in all subjects. RMR measurements were made in the laboratory using a Deltatrac (ventilated-hood indirect calorimeter; Datex, Helsinki, Finland). All subjects had fasted overnight for 12 h and refrained from strenuous exercise before measurements. The intra-individual CV in RMR (kJ/d) after T1 and T2 was 2.5 % in women and 3.6 % in men and was 2.6 % in women and 3.4 % in men after all three sets of measurements. Although mean RMR did not vary across T1, T2 and T3, there was significant "crossing tracks" across the three measurement occasions in some individuals, reflecting a high degree of within-subject variability. The methods used had a significant measurement error associated with them (high R value; significant F ratio in three-way ANOVA). In conclusion, the results from the present study indicate that intra-individual variation in RMR was low in older people. The intra-individual variation in the elderly is similar to that seen in younger age groups.

Aged↗

PubMed2003

Trends in body size, diet and food availability in the Cook Islands in the second half of the 20th century.

The body size of adult Cook Islanders on Rarotonga for the years 1952, 1966 and 1996 has been increasing. The rate of increase in stature of women aged 20-39 years was 0.5cm per decade across the period 1952-1966, and 0.8cm per decade for the period 1966-1996. The rate of increase of weight in the 20-29 years age group was 0.6kg per decade in period 1, and 7.3kg per decade in period 2. In the age group 30-39 years, the rates were 3.2kg per decade and 5.1kg per decade respectively. Changing food availability for the period 1961-2000 is used to compare estimates of dietary energy availability with estimates of physiological energy requirements. There has been reduced availability of traditional staples, a likely reduction in consumption of fish, increased consumption of meat, and a decline in the availability of dietary fats and oils. Daily per capita energy intakes in 1952 and 1966 greatly exceed an hypothetical physiological maximum value for energy expenditure, suggesting a large positive energy balance in 1952 and an even greater one in 1966, both predisposing to weight gain. Although daily per capita energy availability in 1996 is similar to the hypothetical physiological maximum value for energy expenditure, it exceeds the measured level of energy expenditure at that time. It is speculated that excessive energy intake relative to requirement is more likely to predispose to positive energy balance and weight gain than decline in energy expenditure, although to a lower extent than in 1966 and 1952.

Adult↗

PubMed2002

Serum insulin-like growth factor-I, insulin-like growth factor binding protein-3, and the pubertal growth spurt in the female rhesus monkey.

While there is good evidence suggesting IGF-I links to pubertal development and crown-rump length growth among rhesus monkeys, linkages between IGF-I and other measures of morphological growth have not been established. In this study, the pubertal growth spurt in a number of morphological characteristics of female rhesus monkeys is related to serum endocrine status of insulin-like growth factor-I (IGF-I) and its binding protein, insulin-like growth factor binding protein-3 (IGFBP-3), to test the hypothesis that elevations in IGF-I and IGFBP-3 coincide with the time of greatest growth rate of different morphological characteristics. A longitudinal study of pubertal growth among four female rhesus monkeys was carried out across a 3-year period. Morphometric measurements included weight, crown-rump length, foot-length, and skinfolds at five sites (biceps, triceps, abdominal, subscapular, and suprailiac). These measures were taken as being representative of total mass, skeletal growth of the trunk and head, limb length, and body fatness, respectively. Measurements were carried out as closely as possible to 3-monthly, with interpolations being performed to standardise the data to exactly 3-monthly intervals for all individuals. Blood samples were taken at time of morphometry. Elevations in serum IGF-I and IGFBP-3 took place in a manner similar to that of humans, and across the period associated with onset of puberty. Mean 3-monthly gain in crown-rump length and foot length showed significant peaks across the measurement period, while mean 3-monthly gains in weight and sum of five skinfolds did not. Greatest foot length gain occurred on average between 3-3.5 years of age, while crown-rump length gain was greatest between 3.75-4 years of age. Periods of greatest gain in crown-rump length and foot length took place across the period of elevated serum IGF-I levels, which was between 3-4.5 years of age. Significant elevations in IGF-I and IGFBP-3 were not coincident with greatest gains in foot length or crown-rump length. Thus the hypothesis does not hold true for the two measures showing significant peaks in 3-monthly gain across the measurement period. The nature of the endocrine impact on macaque morphology remains unclear, although this may be fundamental to the understanding of the variation in the pubertal growth spurt and its influence on morphology at maturity both within and across primate species.

Animals↗

PubMed2002

Human eating behaviour in an evolutionary ecological context.

Present-day human eating behaviour in industrialised society is characterised by the consumption of high-energy-density diets and often unstructured feeding patterns, largely uncoupled from seasonal cycles of food availability. Broadly similar patterns of feeding are found among advantaged groups in economically-emerging and developing nations. Such patterns of feeding are consistent with the evolutionary ecological understanding of feeding behaviour of hominids ancestral to humans, in that human feeding adaptations are likely to have arisen in the context of resource seasonality in which diet choice for energy-dense and palatable foods would have been selected by way of foraging strategies for the maximisation of energy intake. One hallmark trait of human feeding behaviour, complex control of food availability, emerged with Homo erectus (1.9 x 10(6)-200000 years ago), who carried out this process by either increased meat eating or by cooking, or both. Another key trait of human eating behaviour is the symbolic use of food, which emerged with modern Homo sapiens (100000 years ago to the present) between 25000 and 12000 years ago. From this and subsequent social and economic transformations, including the origins of agriculture, humans have come to use food in increasingly elaborate symbolic ways, such that human eating has become increasingly structured socially and culturally in many different ways.

Animals↗

PubMedDate not supplied

Energetics and evolution: an emerging research domain.

The study of energetics is important to human biology because the availability and utilization of food energy influence health, survival, and reproduction. Over the last decade, human biologists, biological anthropologists, and other evolutionary scientists have increasingly come to recognize the importance of energy dynamics in shaping evolutionary processes. Thus far, different lines of energetics research have been conducted largely in isolation from one another. This thematic collection examines topics of evolutionary energetics from several different perspectives, drawing together research from human paleontology, comparative primate and mammalian biology, human population biology, and mathematical modeling. It represents a starting point for further integrative research on human evolutionary energetics.

Animals↗

PubMedDate not supplied

Comparative energetics of primate fetal growth.

Among the primates, Homo sapiens has evolved a life history which includes long gestation, relatively slow growth to reproductive maturity, and large body size. While the slow growth rate may be linked to the energetic demands of having a large brain, there are other important morphological and physiological linkages that may be adaptive, including the development of significant fat stores with which to buffer against episodic and periodic energetic stress. In this comparative analysis of the energetic burden of pregnancy among primates (including humans), the daily energy investment in the development of neonatal tissue is modeled. During pregnancy, larger primates, notably the Hominidae, invest a smaller proportion of their maternal daily nonmaintenance energy budget in fetal tissue with increasing energy budget, allowing diverse adaptations, including foraging strategies which include folivory and mixed patterns of food getting, and meat consumption. Humans have a similar proportion of maternal daily nonmaintenance energy budget invested in fetal tissue with increasing energy budget to other apes and have a diet which is of much higher quality than predicted for body size and metabolic needs. The combination of high diet quality and low proportion of maternal daily nonmaintenance energy budget invested in fetal tissue allows greater brain size relative to body weight at birth compared with all other primates, apart from chimpanzees, and higher birthweight and body fatness at birth for a given body size than other primate species.

Analysis of Variance↗

PubMedDate not supplied

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.

Agriculture↗

PubMedDate not supplied

Village distance from urban centre as the prime modernization variable in differences in blood pressure and body mass index of adults of the Purari delta of the Gulf Province, Papua New Guinea.

OBJECTIVE: The study examined the extent to which the geographical proximity of villages to an urban centre and other modernization variables are associated with variation in blood pressure and body mass index (BMI) of adults of the Purari delta of the Gulf Province, Papua New Guinea (PNG). METHODS: Mean BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP) of 292 adults surveyed in 1995-1997 in the Purari delta, PNG, are reported by village of residence, and related to modernization variables, including village of residence, urban life, urban connectedness, economic status and education. RESULTS: Mean BMI, SBP and DBP differ according to village of residence, there being a gradient in mean blood pressure from highest in the village closest to the urban centre, Baimuru, and lowest in the village most distant from it. The gradients in these variables across the three villages are not due to differences in age structures between the villages. Place of residence, which represents the distance from town, has the greatest impact on the BMI of males, while among the females, the number of relatives living in urban centres had a significant effect on BMI. For both males and females, place of residence has the strongest effect on SBP. While for the males, place of residence is the only significant factor associated with SBP, for the females, SBP is also associated with BMI, level of income and to a lesser extent with age. Very similar results were obtained for DBP. CONCLUSIONS: Distance to urban centre appears to have a strong effect, relative to other modernization variables, on BMI and blood pressure, this effect being far stronger for males than for females. In large part, this effect operates by way of differences in number of sources of income as well as number of close relatives of women who are resident in an urban centre. Reasons for the male-female differences observed may include gender differences in degree of mobility, and possibly greater physical sensitivity of males to the environment than females. Traditionally, there have been clear divisions of labour between males and females, the latter spending longer in subsistence activities than the former. It is speculated that males have more free time to travel to town should they wish, while women may travel to town to take produce to market, and be limited by how much time they spend in town when they are there, by the need to return to carry out household and subsistence tasks. It may also be that young adult males are more susceptible to modernization, in that they exhibit a greater degree of non-conformity than young women, and may be more favourably disposed to adopt aspects of western lifestyle.

Adult↗