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At least 19 recordsLinked to original sources
PubMed1979

[Correlations between the secular trend in sugar consumption in England and the secular increase of brain weight in adults in London between 1860 and 1940].

Significant positive correlations exist between the secular increase in brain weight of adults in London born between 1860 and 1940, and the secular trend in sugar consumption in the United Kingdom. These results of statistical analysis confirm once again the important bearing of excessive sugar consumption on the development of pre- and postnatal growth acceleration. The pathophysiological interactions of this development are discussed in the light of the experimentum naturae of the IDM (infant of the diabetic mother) and an attempt is made to explain the difference in brain weight increase between males and females.

Anthropometry↗
PubMedDate not supplied

Secular change in height, sitting height and leg length in rural Oaxaca, southern Mexico: 1968-2000.

OBJECTIVE: To evaluate secular changes in height, sitting height and estimated leg length between 1968 and 2000 in residents in a rural Zapotec-speaking community in Oaxaca, southern Mexico. MATERIALS AND METHODS: Height and sitting height were measured in school children 6-13 years (1968; 1978, 2000), in adolescents 13-17 years (1978, 2002) and adults 19-29 years (1978, 2000). Leg length was estimated as height minus sitting height. The sitting height/ height ratio was calculated. Subjects were grouped by sex into four age categories: 6-9, 10-13, 13-17 and 19-29 years for analysis. The Preece-Baines Model I growth curve was fitted to cross-sectional means for 1978 and 2000. RESULTS: There were no differences between children 6-9 and 10-13 years in 1968 and 1978 with the exception of the sitting height ratio in girls 6-9 years. Children of both sexes 6-13 years and adolescent boys 13-17 years were significantly larger in the three dimensions in 2000 compared to 1978; adolescent girls differed only in height and sitting height. Adult males in 2000 were significantly taller with longer legs than those in 1978, but the samples did not differ in sitting height and the ratio. Adult females in 1978 and 2000 did not differ significantly in the three dimensions. Rates of secular change in height and sitting height between 1978 and 2000 were reasonably similar in the three age groups of male children and adolescents, but the rate for estimated leg length was highest in 10-13-year-old boys. Secular gains were smaller in adult males, but were proportionally greater in estimated leg length. Girls 6-9 and 10-13 years experienced greater secular gains in height, sitting height and estimated leg length than adolescent and young adult females, while secular gains and rates decreased from adolescent girls to young adult women. Ages of peak velocity for height, sitting height and estimated leg length declined in boys, while only ages of peak velocity for height and estimated leg length declined in girls. CONCLUSIONS: There are major secular increases in height, sitting height and estimated leg length of children and adolescents of both sexes since 1978. Secular gains in height are of similar magnitude in boys and girls 6-13 years, but are greater in adolescent and young adult males than females. The secular increase in height of young adults of both sexes is smaller than that among adolescents. Estimated leg length accounts for about 60% of the secular increase in height in children of both sexes. Estimated leg length and sitting height contribute equally to the secular increase in height in adolescent boys, whereas estimated leg length accounts for about 70% of the secular increase in height in young adult males. Sitting height contributes about two-thirds of the secular increase in height in adolescent and young adult females.

Adolescent↗
PubMed1990

Research on secular trends in auxology.

Current status of research on secular trends in growth and maturation is considered from several perspectives. The need to define secular trends as positive, negative or absent is initially discussed. Positive secular trends, i.e., increases in size and earlier maturation, characterize the majority of the auxological literature. However, some populations have experienced negative secular trends or no trends. Positive secular trends and cessation of secular trends in stature and age at menarche are described for developed countries, followed by a brief discussion of secular changes in body proportions and composition. Data from developing countries illustrate all three types of secular trends. Some segments of the population show positive changes in size and age at menarche, while others show no evidence of secular change or negative secular trends. Finally, comparisons of estimated statures in earlier European populations suggest a negative secular trend, i.e., a decline in estimated stature from about the 11th to the 19th centuries, which is followed by a positive secular trend starting about the mid-19th century.

Adolescent↗
PubMed1979

Secular trends in human growth, maturation, and development.

Rates of growth during childhood have increased considerably during the past 50-100 years. Because they are associated with increased rates of maturation, these size increases are maximal at ages when recently measured groups are pubescent but those measured in the past had not reached pubescence. Large secular increases in rates of growth and maturation have occurred in all developed countries but not in many other countries. There have been secular increases in recumbent length at birth in Italy and France but little change in the United States. The secular increase in childhood stature is much more obvious, being about 1.5 cm/decade for 12-year-old children, although for young adults the secular increase in stature has been about 0.4 cm/decade in most developed countries. In the United States these trends have been similar for blacks and whites during childhood but greater for black men than white men. Similarly, secular trends in birth weights have been small, but there have been large trends for children (about 1.5 kg/decade for 12-year-olds). These secular changes in size have been associated with an acceleration of maturation that is most evident in the 0.3 years/decade advancement in age at menarche. This advancement has now ceased in Norway and England. The changes in body proportions during recent decades are less marked than those in body size. Leg length, particularly the length of the thigh, seems to have increased more than stature in men but not women; chest circumference has increased more rapidly than stature in each sex. The relationships between stature and weight have changed in different ways in various national groups. Similarly, the relative changes in head length and head breadth vary with the groups studied. Few sets of data allow conclusions about possible secular trends in body composition, but subcutaneous fat thicknesses have increased, especially at the upper percentiles. Also strength, which reflects muscle mass, has increased absolutely, although it has decreased relative to stature. Undoubtedly the secular trend is due to various factors; the identification of causes is necessarily speculative. Changes in nutrition alone could not account for the trends which exceed the original socioeconomic differentials. In the United States, there have been per capita increases in the intake of protein and fat from animal sources, decreases in carbohydrates and fat from vegetable sources, and little change in caloric intake. It is not clear that these changes constitute better nutrition. The secular trends could reflect environmental improvements, specifically changes in health practices and living conditions leading to improvements in mortality rates and life expectancy. These factors are interrelated with those concerning family size. Also genetic factors, especially heterosis, may have played a small role in causing the secular trends...

Body Composition↗
PubMed1975

Stature and secular trend among Southern African Negroes and San (Bushmen).

Despite a wide belief that little information is available on the dimensions of Southern African peoples, data for adult mean stature are presented for no fewer than 123 samples of S.A. Negro (93) and Khoisanoid (30) peoples. Many are published here for the first time. These have made possible a search for signs of the secular trend towards increased adult stature. Two main techniques are the study of longitudinal data (where time-spaced studies on the same population are available) and of age-ranked, cross-sectional data (where the lack of declining stature with age connotes the absence of a secular trens). Most Southern African populations for which data are available show either the absence of the secular trend (previously recognized) or a frankly reversed secular trend (a new concept), in which adults show a decline in mean stature compared with earlier generations. Similar absence or reversal of the secular trend characterizes peoples in Malawi, Kenya, Uganda, Sudan, Senegal, Upper Volta and Ivory Coast, as well as some Asian and South American samples. In the main, developed areas show the secular trend, while less developed areas show an absence or reversal of the trend. To this generalization, the San are a striking exception. All the evidence, first adduced in 1962, points to the usual secular trend as occurring in the San, despite their lowly, undeveloped economic status. Although the data are imperfect, it is possible too, that Xhosa and Moçambique Maravi show evidence of a positive secular trend. "The adult form of mankind is the outcome of growth enhanced, dwarfed, warped, or mutilated by the adventures of life. I am not decrying heredity. But I do insist that new knowledge gained for anthropology through the study of growth brings hope and confidence where formerly was only the grim figure of destiny." (T. Wingate Todd, 1935).

Adolescent↗
PubMed2004

The effects of religious versus secular education on suicide ideation and suicidal attitudes in adolescents in Turkey.

BACKGROUND: Religion is associated with lower rates of self-killing, but the mechanism underlying religion-suicide association is not clear. To better understand this relationship, the present study investigated the impact of religious versus secular education on suicidal ideation and attitudes towards suicide and a suicidal close friend in Turkish adolescents. Deduced from religious commitment, social integration, networking and stigma perspectives, the study tested five specific predictions. METHOD: A questionnaire was used to collect the data in a group of adolescents (n = 206) undergoing religious education and a group of adolescents (n = 214) undergoing secular education (N = 420). RESULTS: Suicide ideation was more frequent in adolescents undergoing secular education than in those undergoing religious education. The secular group was more accepting of suicide than the religious group. Those from the religious group, however, were more accepting of a suicidal close friend than their secular counterparts. CONCLUSION: It seems that self-killing finds accepting attitudes in secular segments of societies and,hence, people consider self-killing as an option during times of personal crises. People from religious communities, however, seem not to accept self-killing as an option, but they are more positive toward persons who have considered suicide for one reason or another.

Adolescent↗
PubMed1999

Secular change in long bone length and proportion in the United States, 1800-1970.

We examine secular change in long bone lengths and allometry of Americans dating from the mid-19th century to the 1970s. Skeletal samples were derived from the Huntington Collection, Terry Collection, World War II casualties, and the Forensic Anthropology Data Bank. Regression of bone length on year of birth allowed evaluation of the secular change in bone length. Size was computed as the geometric mean of all bone lengths, and shape as the ratio of each bone to size. These variables were then regressed on year of birth, allowing evaluation of allometric secular change. The results revealed a pattern of change that can be summarized as follows: male secular change is stronger than female, lower limb bone secular change is more pronounced than upper limb bone change, and distal bones change more than proximal bones, particularly in the lower limb. In males, white changes are uniformly higher than black but these differences do not rise to the level of statistical significance. Environmental forces, such as nutrition and disease, are the usual causes of secular changes in overall size. This paper shows that long bone proportions also respond to these same environmental factors. Moreover, the changes in body proportion are likely to be due to allometric consequences of growth changes that occur early in life. Am J Phys Anthropol 110:57-67, 1999.

Anthropometry↗
PubMed2000

Secular trend in body height and weight of Australian children and adolescents.

Secular changes in growth and maturation have been well documented in various world populations, with secular increase especially noticeable in the developed countries. To assess the trend in both adult size and tempo of growth we compared the data on stature and body weight obtained in 1992-1993 from 1,804 Melbourne school students aged 5 to 17 with historical data collected from white Australians during the last 100 years. We illustrate the age-dependent trend in stature and body weight by means of regression surfaces. These were constructed by fitting local regression models to historical data and by simple plots showing the overall, and per decade, secular increase in both these measures at peripubertal and adult ages. Because of limited information on sample sizes and variability provided by the historical data, statistical comparisons have been performed only between the present 1992-1993 survey and two earlier independent surveys conducted in 1985 and 1970. The results have shown secular increase in adult stature over the last century, with the rate of increase varying between 0.4 and 2.1 cm/decade in males and 0.01 and 1.6 cm/decade in females. While secular increase in stature has significantly slowed down during the last two decades, the increase in body weight is still continuing at a high rate, and this increase is more pronounced in females. The period of strong secular increase, especially in the tempo of growth, coincided both with the shift toward earlier menarche and the improvement of socioeconomic conditions of the Australian population. The need for further studies to identify factors determining the continuing increase in body weight is emphasized, and caution in using the existing national growth standards for stature and weight is recommended.

Adolescent↗
PubMed1980

Secular trend in the stature and weight of Mexican-American children in Texas between 1930 and 1970.

Statures and weights for four samples of Mexican-American children in Texas, measured in 1929-1931 and 1968-1972, were evaluated for evidence of a secular trend. The age range was 6 to 18 years, with more complete data from 8 through 15 years. There is no secular increase in the statures and weights of 6 year old children, a small increase in 8 year old children, and a larger secular increase at 10, 12, 14, and 15 years of age. From about 9 or 10 years of age on, the more recent Mexican-American children tend to have greater weights for their heights. The magnitude of the secular change per decade, however, is considerably smaller than rates for US black, white, European, and Japanese children. The estimated rates of secular change in stature for Mexican-American children approximate about one-fourth to one-half of the generalized rates for European and North American children offered by Meredith ('76) and Tanner ('77). Reasons for a limited secular trend in Texas Mexican-American children are probably bound to the matrix of lower socioeconomic circumstances, poorer health conditions, and marginal nutritional status.

Adolescent↗
PubMed2006

Craniofacial dimensions in children in rural Oaxaca, southern Mexico: secular change, 1968-2000.

The objective of this investigation was to analyze the underlying cause(s) of secular changes in craniofacial dimensions among indigenous children in an isolated community in Oaxaca, southern Mexico, between 1968-2000. Subjects were schoolchildren resident in a rural, agrarian, Zapotec-speaking community in the Valley of Oaxaca, previously characterized as mildly-to-moderately undernourished with growth-stunting in 1968 and 1978. In 2000, children had experienced a secular increase in height compared with two prior growth surveys. Four craniofacial dimensions (head length, head breadth, and bizygomatic and bigonial breadths) were measured during anthropometric surveys of schoolchildren aged 6-13 years in 1968, 1978, and 2000. Cephalic and zygomandibular indices were calculated. Samples by survey were: 1968, 151 males and 157 females; 1978, 179 males and 184 females; and 2000, 180 males and 186 females. The analysis was based on a total of 1,037 children. Multivariate analysis of covariance was used to assess secular trend effects, with height, age, and age2 as covariates by sex. Over the interval of 32 years, significant secular changes occurred in craniofacial dimensions and one index: 1) head length was shorter in boys and girls; 2) bizygomatic breadth was narrower in boys and girls; 3) head breadth increased over time only among girls; 4) brachycephalization increased significantly in a linear manner among both sexes; and 5) the zygomandibular index decreased significantly only in boys. Thus, the cranial complex remodeled to a shorter head length, both relatively (brachycephalization) and absolutely. Remodeling over time also resulted in a narrower face, with the midface changing at about the same rate as the lower face (i.e., mandible). Secular changes are generally recognized as multifactorial. Changes in the cephalic index and cranium over time in schoolchildren in an isolated rural agrarian Zapotec-speaking community in the Valley of Oaxaca suggest that the underlying forces for the secular change are associated: 1) decreased food (maize) coarseness or grit content (masticatory stress), and 2) relaxed natural selection, resulting in 3) a greater role for developmental plasticity.

Adolescent↗
PubMedDate not supplied

Secular change in age at menarche in rural Oaxaca, southern Mexico: 1968--2000.

OBJECTIVE: To evaluate secular change in the age at menarche between 1978 and 2000 in residents of a rural Zapotec-speaking community in Oaxaca, southern Mexico, using status quo and retrospective methods. MATERIALS AND METHODS: Status quo menarcheal status of girls 9-18 years of age in 1978 (n= 101) and 2000 (n=238) and retrospective ages at menarche of adult women 19+ years of age in 1978 (n = 228) and 2000 (n = 246) were obtained via interview. Probit analysis was used to estimate median ages at menarche and 95% confidence intervals (CI) for the status quo data. Analysis of variance and linear regression was used to compare the retrospective data across surveys. RESULTS: The median ages at menarche of adolescents are 14.8+/-1.2 years (0.24 year, 95% CI 14.2-15.4 years) in 1978 and 13.0+/-1.0 years (0.10 year, 95% CI 12.7-13.3 years) in 2000. Age at menarche has declined by 1.8 years over about 23 years, 0.78 year/decade (95% CI = 0.65-0.91 year/decade). Recalled ages at menarche do not differ by age group in the 1978 survey, but differ significantly by age group in the 2000 survey (p <0.001). Within the 2000 survey, the two youngest age groups (< 29, 30-39 years) do not differ, but attain menarche earlier than women in the four older age groups (p < 0.05), who do not differ from each other in age at menarche. The estimated rates of secular decline in age at menarche in adult women vary between 0.38 and 0.42 years/decade (0.26-0.56 year/decade). CONCLUSIONS: There is a major secular decline in the age at menarche of adolescent girls and young adult women between 1978 and 2000. The estimated rate of decline in adult women is about one-half of that in adolescent girls. The secular decline in age at menarche is consistent with corresponding secular gains height, sitting height and estimated leg length of children and adolescents in the community; corresponding secular gains are smaller in young adults 19-29 years.

Adolescent↗
PubMed2006

Opportunity for natural selection and gene flow in an isolated Zapotec-speaking community in southern Mexico in the throes of a secular increase in size.

Our object in this paper is to analyze the opportunity for natural selection and gene flow in an isolated Zapotec-speaking community in the valley of Oaxaca, southern Mexico, that is undergoing a secular increase in body size. Surveys were conducted in the community in 1968, 1978, and 2000, including anthropometric and census data. No secular change was found in the growth status of schoolchildren and adult height between 1968 and 1978; subsequently, major secular gains in height occurred among children and adolescents between 1978 and 2000. The 1978 household data were used to compute gene flow (3.3%) and opportunity for selection intensity (I = 1.312). Migration and other demographic information was obtained from household census data for 1978 and 2000, and mortality information was extracted from community records and archives. These data were used to compute gene flow and opportunity for natural selection. Gene flow increased from 3.3% to 4.7% and intensity of natural selection decreased from 1.312 to 0.272 from 1978 to 2000. Variance in fertility increased slightly over time (12.25 to 13.69). Opportunity for selection was dominant during the prereproductive period in 1978, but approached 0 for the mortality component in 2000, resulting in a marked decrease in the mortality component (Im) of selection (0.626 and 0.019, respectively) and total opportunity for selection (I = 1.312 and 0.272, respectively). Secular increase in height and markedly decreased opportunity for natural selection (1) were associated with better health and nutritional conditions. Genotype-environment interaction and environmental influences are apparently the predominant causes of the secular trend. If natural selection plays a role in causing the secular trend, it is a small one.

Adolescent↗
PubMed2006

Longitudinal and secular trends in physical activity and sedentary behavior during adolescence.

OBJECTIVE: There is little epidemiologic research on longitudinal and secular trends in weight-related health behaviors throughout the stages of adolescence. In particular, few data are available to assess secular trends in various sedentary behaviors. The objective of this research was to investigate longitudinal and secular trends in physical activity and sedentary behavior in a large, diverse cohort of adolescents. METHODS: Project EAT-II is a 5-year longitudinal study (N = 2516) that includes 2 cohorts that allow for the observation of longitudinal changes from early to midadolescence (junior high to high school; n = 806; mean baseline age: 12.8 +/- 0.8 years) and mid- to late adolescence (high school to post-high school; n = 1710; mean baseline age: 15.8 +/- 0.8 years). EAT-II also examined secular trends in health behavior from 1999 to 2004 in midadolescence. The main outcome measures of the mixed-model regression analyses used in this research were self-reported weekly hours of moderate to vigorous physical activity, television/video viewing, and leisure-time computer use. RESULTS: Our findings indicate substantial longitudinal changes in moderate to vigorous physical activity, particularly among girls (decreasing 5.9-4.9 hours/week from early to midadolescence and 5.1-3.5 hours/week from mid- to late adolescence), and leisure-time computer use, particularly among boys (increasing 11.4-15.2 hours/week from early to midadolescence and 10.4-14.2 hours/week from mid- to late adolescence). Secular trends further indicate dramatic increases in midadolescent computer use from 1999 to 2004; girls increased from 8.8 to 11.1 hours/week, and boys increased from 10.4 to 15.2 hours/week. CONCLUSIONS: These adolescents experienced unfavorable shifts in activity patterns, such as longitudinal decreases in moderate to vigorous physical activity, coupled with longitudinal and secular increases in leisure-time computer use. Developing effective health promotion strategies that address a wide array of changing behavioral patterns will be important in promoting long-term health and active lifestyles among adolescents and young adults.

Adolescent↗
PubMed1999

A sensitivity analysis of secular trends in risk factors and mortality based on cohort studies.

Because of a "healthy responder effect," secular trends in mortality based on cohort studies may be biased if based on responders only. Because responders are selected on the basis of their health at study entry, subjects just entering a study are not comparable with subjects who have been in the study for several years. The result may be an artificial increase in mortality, which impedes analyzing the effect of secular trends in risk factors on mortality. The objective of this paper is to suggest a solution by using data on nonresponders and applying a sensitivity analysis. We illustrate this solution with data on trends in smoking prevalence and all-cause mortality based on a large Danish cohort study with 19 years of complete follow-up on responders and nonresponders. Secular trends in mortality based on the whole sample vs responders only illustrated that results based on responders were biased. In a sensitivity analysis, the observed person-years of nonresponders were distributed among six categories of persons with respect to smoking behavior (never-smokers; ex-smokers; noninhaling current smokers; and current smokers of 1-14, 15-24, and > or =25 gm tobacco per day) according to preset assumptions regarding smoking habits. The observed deaths among nonresponders were then distributed on the six smoking categories according to relative risks derived from a Poisson regression analysis among responders. This procedure allowed us to study the effect of adjustment for smoking on the unbiased secular trend in mortality. By applying different assumptions regarding smoking habits among nonresponders, we explored the effect of the assumptions on the adjusted secular trend in mortality. We conclude that secular trends in mortality based on responders in a cohort study are likely to be biased. If complete follow-up on nonresponders is available, this method could prove useful in other cohort studies.

Aged↗
PubMed1990

Secular changes in stature in southern Portugal between 1930 and 1980 according to conscript data.

Stature of conscripts from four regions of southern Portugal was evaluated in a secular perspective. Data were drawn from the draft records for each decade between 1930 and 1980, a period that corresponds to a decisive expansion of industry and urbanization. In each region conscripts were divided into two groups according to their area of birth: urban or rural. A secular shift was apparent in every region, affecting conscripts of both urban and rural extraction. However, gains in stature were greater in the littoral than in the hinterland regions, where agriculture still employs a large percentage of the population. In each region the urban conscripts experienced greater secular gains than their rural counterparts. The secular shift was more pronounced among the short-stature segments of the populations; percentages of conscripts below a height of 160.0 cm dropped in a striking manner throughout the period under investigation. Despite the paucity of reliable information on the anthropometric and biodemographic characteristics of the Portuguese population, the secular gains were found to be associated with infant mortality and total death rate in the four regions. Compared to other Western European populations, the secular growth of the Portuguese proceeds at a slower pace, even when comparisons are made within the group of Latin countries that share a common linguistic and cultural heritage in addition to the shortest statures in Europe.

Body Height↗