Secular trends in male adult height 1904-1996 in relation to place of residence and parent's educational level in Portugal

Life History Transitions at the Origins of Agriculture: A Model for Understanding How Niche Construction Impacts Human Growth, Demography and Health

Over recent millennia, human populations have regularly reconstructed their subsistence niches, changing both how they obtain food and the conditions in which they live. For example, over the last 12,000 years the vast majority of human populations shifted from foraging to practicing different forms of agriculture. The shift to farming is widely understood to have impacted several aspects of human demography and biology, including mortality risk, population growth, adult body size, and physical markers of health. However, these trends have not been integrated within an over-arching conceptual framework, and there is poor understanding of why populations tended to increase in population size during periods when markers of health deteriorated. Here, we offer a novel conceptual approach based on evolutionary life history theory. This theory assumes that energy availability is finite and must be allocated in competition between the functions of maintenance, growth, reproduction, and defence. In any given environment, and at any given stage during the life-course, natural selection favours energy allocation strategies that maximise fitness. We argue that the origins of agriculture involved profound transformations in human life history strategies, impacting both the availability of energy and the way that it was allocated between life history functions in the body. Although overall energy supply increased, the diet composition changed, while sedentary populations were challenged by new infectious burdens. We propose that this composite new ecological niche favoured increased energy allocation to defence (immune function) and reproduction, thus reducing the allocation to growth and maintenance. We review evidence in support of this hypothesis and highlight how further work could address both heterogeneity and specific aspects of the origins of agriculture in more detail. Our approach can be applied to many other transformations of the human subsistence niche, and can shed new light on the way that health, height, life expectancy, and fertility patterns are changing in association with globalization and nutrition transition.

Is the secular trend in height delaying overweight rise among adolescents? The Brazilian case

OBJECTIVE

To explore if the secular trend in height is contributing to delay overweight rise among Brazilian adolescents.

DESIGN

Changes in BMI mean over time were fitted using linear regression including as independent variables survey year, height, survey-specific income quintiles, age and an interaction term of height × survey year. Overweight was defined as BMI≥25·0 kg/m2. Changes in overweight prevalence over time were fitted using Poisson regression.

SETTING

Four national household surveys: 1974/5, 1989, 2002/3 and 2008/9.

SUBJECTS

Brazilian adolescents.

RESULTS

Mean values of height and BMI increased over the period, for both sexes and in all age ranges, except for girls aged 14-19 years from 1989 to 2002/3. The highest average increment and mean rate of height were between 1989 and 2002/3 and in 10-15-year-olds. The annual increment of height decreased from 2002/3 to 2008/9 in parallel with the increment in BMI rate. After fitting the regression model, the height × survey year interaction and per capita income were strong vectors to increase BMI mean. Changes in increment rate of height played a protective role against overweight in the last two periods for both sexes, mainly for girls. The period from 1989 to 2002/3 was the strongest vector associated with overweight in boys and the association decreased to the next period, from 2002/3 to 2008/9.

CONCLUSIONS

BMI and height of adolescents have increased in a wavering and alternate way throughout four decades in Brazil. The rate of height increment has played a protective role against overweight in adolescents.

Are chronic diseases related to height? Results from the Portuguese National Health Interview Survey

This paper analyze the association between height and chronic diseases in Portugal and the extent to which this relationship is mediated by education. The sample upon which the analysis is based comprised those participants in the 2005/2006 Portuguese National Health Interview Survey (n=28,433) aged 25-79. Logistic regressions measured the association of height with ten chronic diseases, adjusting for age, lifestyle, education, and other socioeconomic factors. Among women, an additional centimeter in stature significantly decreased the prevalence of asthma, chronic pain, and acute cardiac disease, by 0.057, 0.221, and 0.033 percentage points, respectively. Also, mental disorders were significantly less prevalent in the last quartile of height. Among men, an additional centimeter in height was associated with a 0.074 lower prevalence of asthma, and men in the last quartile of height were significantly less at risk of acute cardiovascular disease. There was no significant association between height and the risk of diabetes, high blood pressure, cancer, and pulmonary diseases. As for the impact of education, women with a tertiary level were on average 5.3cm taller than those with no schooling; among men, the difference was almost 9cm. Adjusting for education reduced the height-related excess risk of ill health by 36% on average among men, and by 7% among women. The analysis indicates that there is a significant association of height with several chronic conditions, and that education plays a mediating role in the height-health connection. By emphasizing the role of height and education as determinants of chronic conditions, this paper also highlights the role of conditions related to childhood health and socioeconomic background.

The influence of inequality on the standard of living: worldwide anthropometric evidence from the 19th and 20th centuries

We provide empirical evidence on the existence of the Pigou-Dalton principle. The latter indicates that aggregate welfare is - ceteris paribus - maximized when incomes of all individuals are equalized (and therefore marginal utility from income is as well). Using anthropometric panel data on 101 countries during the 19th and 20th centuries, we determine that there is a systematic negative and concave relationship between height inequality and average height. The robustness of this relationship is tested by means of several robustness checks, including two instrument variable regressions. These findings help to elucidate the impact of economic inequality on welfare.

Global variance in female population height: the influence of education, income, human development, life expectancy, mortality and gender inequality in 96 nations

Human height is a heritable trait that is known to be influenced by environmental factors and general standard of living. Individual and population stature is correlated with health, education and economic achievement. Strong sexual selection pressures for stature have been observed in multiple diverse populations, however; there is significant global variance in gender equality and prohibitions on female mate selection. This paper explores the contribution of general standard of living and gender inequality to the variance in global female population heights. Female population heights of 96 nations were culled from previously published sources and public access databases. Factor analysis with United Nations international data on education rates, life expectancy, incomes, maternal and childhood mortality rates, ratios of gender participation in education and politics, the Human Development Index (HDI) and the Gender Inequality Index (GII) was run. Results indicate that population heights vary more closely with gender inequality than with population health, income or education.

Re-examining heritability: genetics, life history and plasticity

Human life-history traits (growth, maturation, nutritional status) are increasingly associated with risk of chronic degenerative disease. Twin studies suggest high heritability of such traits; however, although sophisticated approaches have identified genetic variation underlying a proportion of this heritability, studies also increasingly demonstrate significant plasticity, and many life-history traits are able to change by one standard deviation (SD) over 3-6 generations. Developments in our understanding of the contributions of genetics and plasticity to human life history are likely to improve understanding of the growing burden of chronic diseases. We argue that a life-history approach to understanding variation in the human phenotype must integrate these two risk components, and highlight the important contribution of plasticity to changes in disease prevalence.

Patterns and trends of adult height in India in 2005-2006

Differences in height by wealth, education, caste, geography, and birth years are examined for men and women born between 1961 and 1981 in India using data from the 2005-2006 Indian National Family Health Survey. There is a positive association between socioeconomic position (SEP) and height with lower SEP individuals being shorter. Height varies across the 29 Indian states even after accounting for individual differences in SEP, with substantial variation in height remaining at the neighborhood and state levels. Among men, height appears to have modestly increased for all birth cohorts as compared to the 1961-1965 cohort, with smaller increases for the most recent cohorts. For women, height across birth cohorts has shown little increase. These results suggest that inequalities in several health outcomes for low SEP adults may be reflected in inequalities in height, which can be used to represent long-term health at the population level. Shorter stature and slower growth among some groups may indicate that they did not experience the improvements that were assumed to have occurred across the population. This study presents a comprehensive, empirical description of mean height differences and the underlying variation among adults in India across diverse socioeconomic, demographic, and geographically oriented groups as well as birth cohorts.

Secular changes and predictors of adult height for 86 105 male and female members of the Thai Cohort Study born between 1940 and 1990

Background

Height trends can be useful indicators of population health but, despite Thailand's rapid socioeconomic development since the 1950s, few studies have examined accompanying secular changes in adult height or the effects of the transition on the heights of rural versus urban populations. This study therefore sought to document average heights in different age groups of rural and urban Thais and to investigate factors associated with attained height.

Methods

Data from 86 105 Thai Cohort Study participants was used to estimate mean heights for men and women in different birth year groups. Simple regression was used to calculate the change in height per decade of birth year among those based in rural or urban locations as children. Multiple linear regression was used to investigate effects of other childhood factors on height.

Results

Overall, average heights were found to have increased by approximately 1 cm per decade in those born between 1940 and 1990. However, the rate of increase was 0.4–0.5 cm per decade greater among urban-based Thais compared with those from the countryside. Parental education levels, household assets, birth size, sibling number, birth rank and region of residence were also significantly associated with adult height.

Conclusions

These data suggest a marked secular increase in Thai heights in the second half of the 20th century probably reflecting improved childhood health and nutrition over this time. Rural-born Thais, who benefited to a lesser extent from the changes, may face future health challenges with greater risks of, among other things, obesity and its health consequences.

Secular growth changes in stature and weight for Chinese Mongolian youth, 1964-2005

BACKGROUND

A secular growth trend has been demonstrated in China during the past half century. However, few studies have involved minority ethnicity.

AIM

This study demonstrates secular changes in stature and weight for Chinese Mongolians from 1964 to 2005, and analyses the correlations with environmental factors, revealing inequalities within populations.

SUBJECTS AND METHODS

Data were gathered from 7- to 18-year-old students in the Inner Mongolian Autonomous Region of China, both from local records in 1964 and from the 1985, 1991, 1995, 2000 and 2005 cycles of the Chinese National Survey on Students' Constitution and Health.

RESULTS

During the past 41 years, the average rates of stature increments for 7- to 17- year-olds are 1.9 and 2.0 cm per decade, of weight are 2.2 and 1.5 kg per decade and of BMI are 0.5 and 0.3 kg/m(2) per decade, for males and females, respectively. The overall increments of stature in 18-year-old males and females from 1985 to 2005 are 2.3 and 2.1 cm, respectively. The rate of change of stature is stronger in the first three decades, while that of weight and BMI are greater in the last decade. Evidence strongly suggests that changes may have occurred since the late 1970s.

CONCLUSION

The positive growth changes of Chinese Mongolian people are closely related to urbanization, socio-economic progress and living improvements.

Estimation of secular trends in adult height, and childhood socioeconomic circumstances in three Eastern European populations

The objective of these analyses was to estimate the strength and direction of secular trends in adult height and childhood socioeconomic circumstances in eight towns in three Eastern European countries in the mid-20th century, and to assess the extent to which childhood conditions might explain the height differences. We used cross-sectional data from the baseline survey of the Health, Alcohol and Psychosocial factors in Eastern Europe (HAPIEE) study, conducted in 2002-2005. The study examined 24,012 men and women born between 1933 and 1957, randomly selected from the general populations of Novosibirsk (Russia), Krakow (Poland) and six towns of the Czech Republic. To allow for age-related height loss we estimated maximum attained height. Parental education and household item ownership at age 10 were used as markers of childhood socioeconomic conditions. In all 5-year birth cohorts, Novosibirsk men and women were shortest. There were positive and statistically significant secular trends in childhood conditions and in maximum adult height. Adjustment for childhood conditions explained about one third of the trend in height. There appeared to be a small reduction in height of persons born during the Second World War which was, however, only significant in Novosibirsk. These results suggest that secular trends in height mirror, but are not wholly explained by, trends in socioeconomic circumstances in early life.

Changes in body size, shape and nutritional status of middle-class Bengali boys of Kolkata, India, 1982--2002

Growth changes over time among school-aged boys in Kolkata, India, have been investigated using two surveys: 1982--1983 (n=816) and 1999--2002 (n=1187). The two surveys were implemented according to highly similar protocols which strongly adds to the reliability and accuracy of the results of the study. Age-specific average height, weight and BMI all increased during these two decades (by respectively, 3.2cm, 6.1kg and 2.1kg/m2), while relative sitting height and sitting height-subischial leg length ratio decreased for almost all ages between 7.0 and 16.0 years. Moreover, the prevalence of stunting and thinness declined (stunting from 11.2% to 4.9%, p<0.01, thinness from 50.5% to 22%, p<0.01), while the prevalence of overweight increased (from 4.7% to 17.2%, p<0.01). Through analysis of variance, the relationships between various socio-economic factors and anthropometric traits are analyzed. Factors strongly related with positive changes in anthropometric traits are maternal education and family expenditure.

The relationship between body mass index and educational level in young Portuguese males: 1995 and 1999 cohorts

INTRODUCTION

Over the last decades, a progressive increase in height and weight has been observed throughout Europe. Increase in weight has been more marked however, with a resulting increase in overweight and obesity prevalence. RESULTS published have analyzed the relationship between body mass index (BMI) and educational level. Most studies indicate an inverse relationship between BMI and educational level in developed countries.

OBJECTIVE

This study's main objective was to evaluate the relationship between BMI and educational level (years of schooling) in young Portuguese males in 1995 and 1999.

METHODS

Transverse study of data (BMI and years of schooling) from the military inspection records of virtually the entire Portuguese male population with an average age of 20 years, examined in 1995 and 1999, totaling 81 363 and 71 254, respectively. Four classes of BMI (<20, 20-24.9, 25-29.9 and > or =30 kg/m2) and four schooling levels (<5, 5-9, 10-12, and >12 years) were considered. We applied the chi2 test for associations between BMI and educational level and the odds ratio to quantify categorical variables. The significance level was 5%.

RESULTS

In 1995, 15.2% were overweight (BMI> or =25 years), increasing to 20.8% in 1999. The percentage of obesity (BMI> or =30 years) was 1.4% in 1995 and 2.2% in 1999. The percentage of overweight and obesity increased directly in line with the increase in educational level, both in 1995 and 1999. In 1995, the percentage of subjects with obesity according to years of schooling was as follows: <5 years--1.4%; 5-9 years--1.4%; 10-12 years--1.5% and >12 years--1.7%. In 1999, the results were as follows: <5 years--1.4%; 5-9 years--2.2%; 10-12 years--2.8% and >12 years--3.2%.

CONCLUSIONS

We can conclude that the prevalence of overweight and obesity in young male Portuguese increased in the last decade and that, unlike most developed countries, the higher the level of education, the greater the percentage of overweight and obesity, both in 1995 and 1999.

Are inequalities in height narrowing? Comparing effects of social class on height in two generations

OBJECTIVE

To determine whether social inequalities in height change across generations.

METHODS

The target population was from the 1958 British birth cohort, all born 3rd-9th March 1958, followed to 1991, and the offspring of one third of this population. Main outcomes were height measured at 7, 11, 16, and 33 years (cohort members) and once at 4-18 years (offspring). Multilevel models applied to associations of social class of origin with (a) child-to-adult growth trajectory (cohort members), (b) height (offspring), and (c) generational height increment.

RESULTS

Height inequalities were observed among cohort members, with differences >2.0 cm at all ages between classes I and II, and IV and V. By adulthood, the difference in mean height had declined significantly in boys and slightly in girls. A secular trend was seen between the two generations. While male offspring had a similar mean height to their fathers in classes I and II, boys in classes IV and V gained 2.1 cm (p<0.001). Height gains of female offspring were evident in all classes, with a greater gain in classes IV and V (non-significant). The social class effect on height was weaker among offspring, with a difference between classes I and II, and IV and V of less than 1 cm.

CONCLUSIONS

Social inequalities in height observed among the cohort weakened substantially in the next generation due to a greater height gain among offspring from manual classes. Inequalities in childhood height have narrowed between the two generations in this study.

Social inequalities and children's height in Trinidad and Tobago

OBJECTIVE

The aim of the study was to report the association of socio-economic factors with child's height.

DESIGN

Cross-sectional study based on a representative national sample of government schools.

SETTING

Trinidad and Tobago in 1999.

SUBJECTS

A total of 2608 boys and girls mean age 5.8 y, range 4.38-6.99 y and 3080 mean age 8.6 y, range 7.00-10.44 y olds.

OUTCOME

Measurement of height and a questionnaire completed by parents. In the analysis height was expressed as standard deviation scores (s.d.s.) based on the British height curves (1990) or height below -1.5 s.d.s.

RESULTS

Ethnicity, parental heights, birthweight, maternal age at child's birth and number of children in the family were the main factors associated with children's height. Lack of piped water supply in the home was the only socio-economic factor consistently associated with height (mean difference in s.d.s. adjusted only for age group, gender and ethnicity -0.192, 95% CI -0.257 to -0.127 and in addition adjusted for the variables listed above -0.080, 95% CI -0.141 to -0.019). Parental education, household overcrowding and employment status were weakly associated with height in the partially adjusted model only. Analysis of severe growth failure gave similar results.

CONCLUSION

The impact of socio-economic factors on height is marginal in Trinidad and Tobago. As socio-economic factors may have an impact on a broad range of health indicators, height and rates of undernutrition should not be used as sole criteria for assessing progress in decreasing health differentials caused by social inequalities.

Secular trends in growth

Since the 19th century there have been clearly documented secular trends to increasing adult height in most European countries, with current rates of 10-30 mm/decade. Over the same period menarcheal age has also fallen steeply, but has now stabilized at approximately 13 years and may be rising again. Height trends tend to be greater in childhood than in adulthood due to the associated advance in maturation, but no trends are apparent before the age of 2 years. In particular, birth-weight trends are small and different in shape from height trends. The adult height trend matches that at age 2 years, so that the increment in adult height has already been achieved by age 2 years. To try to identify factors relating to the secular trend, increased height gain in late infancy is hypothesized to be equivalent to a reduction in stunting, and stunting is thought to be caused by impaired growth in the long bones of the leg in later infancy. Leg growth may be regulated by the expression of growth-hormone receptors on the growth plates, which it is hypothesized are susceptible to the interaction between concurrent nutrition and the nominal growth rate set during pregnancy. The timing of menarche is also likely to be determined by some growth factor operating near the time of birth, which also affects later weight, but not height.