D. F. Roberts

Bio: D. F. Roberts is an academic researcher from Newcastle University. The author has contributed to research in topics: Population & Genetic variation. The author has an hindex of 15, co-authored 28 publications receiving 646 citations.

Menarcheal age in University of Warwick young women

Abstract: Data from the final 16 years of a 28-year ongoing survey of menarcheal age are reported. From 1971 onwards, recalled aged at menarche was recorded for all young women entering the University of Warwick. These data show that mean menarcheal age is increasing, a trend which is independent of father's occupation, family size, position of girl in the family, and physique. This continues a similar upward tendency noted in a preceding study in Swansea. It appears that the downward trend to earlier age at menarche of the earlier decades of this century has been replaced by one in the opposite direction.

Influences on menarcheal age in girls in a Welsh College.

Abstract: Of the methods used to obtain estimates of the mean and dispersion of age at menarche in a population, the potential accuracy of two are generally agreed: the prospective method, in which individuals are followed in longitudinal studies throughout the pubertal period, and the status quo method, in which probits or logits are fitted to data from Yes/No questions to girls of known age in the range 9 to 17 years. These two procedures avoid many of the errors and biases that may arise from cross-sectional retrospective studies in which girls are asked to recollect their age when they first started to menstruate. Such errors may arise from the difficulty of exact recollection; this is particular ly so in the case of older women but may also occur at younger ages, for De Wijn (1966) showed that the percentage of teenage girls unable to recollect the exact month increases with the age at which they are asked; but errors of recollection do not always occur, as was shown by Livson and McNeill (1962), who compared recorded age with that remembered 17 years later and found close individual and very close mean concordance. Much depends on the intelligence of the girl and on the clarity of definition of the event. There may be bias if there are any girls in the sample who have not yet menstruated or who give deliberately false answers to emulate their friends; for example, Kark (1943) showed that girls of 18 to 20 gave an average age remembered as 15 to 16 years, whereas those of 15 to 17 gave an average age of 13 to 14 years; Wilson and Suther land (1949), comparing two groups of children in Oxford and in Oxfordshire, snowed that the difference in their respective remembered ages (13-4 and 13*09 years respectively), was entirely due to the inclusion of more pre-pubertal girls in the latter sample, for probit analysis showed an identical

End of the trend? A 12-year study of age at menarche.

Abstract: A 12-year study of menarchial age in all girls entering the University College of Swansea (1959-70) suggests that the downward trend in age at menarche has ceased in Britain. The turning point appears to have occurred in girls born about 1946.

Genetic heterogeneity and population structure in north-west India.

Abstract: Genetic markers consisting of 11 blood group and red cell enzyme systems were investigated in 14 endogamous groups of north-west India. Genetic differentiation among the samples as indicated by FST is appreciable, reflecting the ethnic diversity characteristic of this region. Local variation within each state is lower, indicating a geographical component to the total variation. This variation is refined by calculations of genetic distances, which show that the tribals and low-caste groups are closer together but well separated from high-caste Brahmins and other non-tribal middle castes. There is a slight possibility of disruptive selection, but the analyses suggest that the differences in genetic structure in north-west India are more likely to be due to their breeding structure, differential migration and ethnic affiliation.

Socioeconomic Status and Obesity: A Review of the Literature

Abstract: A review of 144 published studies of the relationship between socioeconomic status (SES) and obesity reveals a strong inverse relationship among women in developed societies. The relationship is inconsistent for men and children in developed societies. In developing societies, however, a strong direct relationship exists between SES and obesity among men, women, and children. A review of social attitudes toward obesity and thinness reveals values congruent with the distribution of obesity by SES in different societies. Several variables may mediate the influence of attitudes toward obesity and thinness among women in developed societies that result in the inverse relationship between SES and obesity. They include dietary restraint, physical activity, social mobility, and inheritance.

Socioeconomic Status and Obesity

Abstract: The objective of this review was to update Sobal and Stunkard’s exhaustive review of the literature on the relation between socioeconomic status (SES) and obesity (Psychol Bull 1989;105:260–75). Diverse research databases (including CINAHL, ERIC, MEDLINE, and Social Science Abstracts) were comprehensively searched during the years 1988–2004 inclusive, using ‘‘obesity,’’ ‘‘socioeconomic status,’’ and synonyms as search terms. A total of 333 published studies, representing 1,914 primarily cross-sectional associations, were included in the review. The overall pattern of results, for both men and women, was of an increasing proportion of positive associations and a decreasing proportion of negative associations as one moved from countries with high levels of socioeconomic development to countries with medium and low levels of development. Findings varied by SES indicator; for example, negative associations (lower SES associated with larger body size) for women in highly developed countries were most common with education and occupation, while positive associations for women in medium- and low-development countries were most common with income and material possessions. Patterns for women in higher- versus lower-development countries were generally less striking than those observed by Sobal and Stunkard; this finding is interpreted in light of trends related to globalization. Results underscore a view of obesity as a social phenomenon, for which appropriate action includes targeting both economic and sociocultural factors.

The timing of normal puberty and the age limits of sexual precocity: variations around the world, secular trends, and changes after migration

Abstract: During the past decade, possible advancement in timing of puberty has been reported in the United States. In addition, early pubertal development and an increased incidence of sexual precocity have been noticed in children, primarily girls, migrating for foreign adoption in several Western European countries. These observations are raising the issues of current differences and secular trends in timing of puberty in relation to ethnic, geographical, and socioeconomic background. None of these factors provide an unequivocal explanation for the earlier onset of puberty seen in the United States. In the formerly deprived migrating children, refeeding and catch-up growth may prime maturation. However, precocious puberty is seen also in some nondeprived migrating children. Attention has been paid to the changing milieu after migration, and recently, the possible role of endocrine- disrupting chemicals from the environment has been considered. These observations urge further study of the onset of puberty as a possible sensitive and early marker of the interactions between environmental conditions and genetic susceptibility that can influence physiological and pathological processes.

Growth at Adolescence.

Abstract: argument is often, if not acrimonious, at least heated. It gives an impression of the fluidity of opinion on many fundamental ideas under discussion and of the urgency with which cardiac cyanosis in the newborn is regarded. When Dr. William Muscott says that the earliest he has operated for pulmonary stenosis is on an infant 3 days old, and Sir Russell Brock agrees that the earlier in the first month that operation is undertaken the better, and when Dr. Varco asks Dr. Senning 'so far as I know they have never yet catheterized any child intrauterine in Sweden, but they have done it through the delivery canal sometimes-would you tell us the indications of the Scandinavian group for catheterization in the immediate newborn period?', one is indeed being kept up with the times. But that was two years ago and already some of the questions then debated have since been answered. This beautifully printed and well-illustrated stiff paperbacked volume is, and will for a few years yet remain, an invaluable companion to a full-scale textbook on congenital heart disease.

Timing of Pubertal Maturation in Girls: An Integrated Life History Approach.

Abstract: Life history theory provides a metatheoretical framework for the study of pubertal timing from an evolutionary-developmental perspective. The current article reviews 5 middle-level theories--energetics theory stress-suppression theory psychosocial acceleration theory paternal investment theory and child development theory--each of which applies the basic assumptions of life history theory to the question of environmental influences on timing of puberty in girls. These theories converge in their conceptualization of pubertal timing as responsive to ecological conditions but diverge in their conceptualization of: a. the nature extent and direction of environmental influences and; b. the effects of pubertal timing on other reproductive variables. Comparing hypotheses derived from the 5 perspectives are evaluated. An extension of W.T. Boyce and B.J. Elliss (in press) theory of stress reactivity is proposed to account for both inhibiting and accelerating effects of psychosocial stress on timing of pubertal development. This review highlights the multiplicity of (often unrecognized) perspectives guiding research raises challenges to virtually all of these and presents an alternative framework in an effort to move research forward in this arena of multidisciplinary inquiry. (authors)