Published today in PLoS Medicine, the study compares reproductive hormone levels of groups of Bangladeshi women who migrated at different periods of their life. It finds that women who migrated from Bangladesh to the UK during infancy and early childhood reach puberty earlier, are taller, and have up to 103 per cent higher levels of the hormone progesterone as adults in comparison to women who migrated at a later age, as well as those who had remained in Bangladesh. These higher hormone levels could potentially increase a woman’s ability to conceive.
Lead author Dr Alejandra Núñez de la Mora, UCL Department of Anthropology, said: “The findings point to the period before puberty as a sensitive phase when changes in environmental conditions positively impact on key developmental stages. Put very simply, the female body seems to monitor its environment throughout childhood and before puberty, to gauge when and at what rate it will be best to mature. It then sets development, including reproductive hormone levels, accordingly. This is an advantage in evolutionary terms, as it makes the best of the resources and energy available for reproduction in any given circumstance.
“Girls who migrate at a young age seem to mature more quickly when they find themselves in an environment where the body has more access to energy. In other words, when they’re under less physical strain due to factors like a better diet and general health. When energy is a limited resource, it must be allocated between maintenance, growth, and reproductive functions – the body makes trade-offs within the constraints it experiences. When conditions are better, these constraints are relaxed and more energy is diverted towards reproduction.”
The results of this study are relevant not only to Bangladeshi groups, but to other migrant groups and populations in transition worldwide. These findings add to accumulating evidence that humans have an evolved capacity to respond to chronic environmental conditions during growth and to make decisions about how to apportion energy between reproductive and other bodily functions.
Five groups of women were selected and compared for the study. These included women who had grown up in Bangladesh but moved to the UK as adults; those who had moved to the UK as children; second generation Bangladeshi women living in the UK; women who were born and raised in Bangladesh; and a comparison group of women of European descent who were born and raised in the UK. Bangladeshi migrants were chosen for this study because of the long and on-going history of migration to the UK and the general contrasts in conditions between the two countries.
The subjects in each group gave saliva samples over an extended period, to measure levels of the female hormones progesterone and oestradiol. These are key fertility hormones, influencing the female menstrual cycle, pregnancy and embryonic development. Health information and body measurements were also provided by the subjects.
Co-author Dr Gillian Bentley, UCL Department of Anthropology, who directed the project added: “The theory that early environmental factors may affect reproductive function has been suggested previously by anthropologists*, but this field study is the first to use measurements of hormone levels to demonstrate a link between childhood environment and reproductive maturation and function. However, hormone levels are not just relevant to reproduction. The significant increase in progesterone levels that we document in migrant women may result, for example, in higher breast cancer risks in subsequent generations of this community. The potential health implications are far-reaching.”
Bangladesh, in South Asia, is one of the most densely populated countries in the world. The Bangladeshis who took part in the study were middle class women from the Sylhet District. Although a relatively affluent area of the country, inhabitants still suffer from higher immune challenges, primarily due to poor sanitation and limited access to healthcare. These aspects of the environment in Bangladesh are thought to be responsible for the slower development of the Bangladeshi women who grew up there.
The study was co-authored by Dr Robert Chatterton in Obstetrics and Gynaecology at Northwestern University, Chicago who supervised the laboratory work, and Dr Osul Choudhury of the Sylhet Osmani Medical College, Bangladesh who co-ordinated research with Dr Núñez de la Mora in Bangladesh.
Dominique Fourniol | alfa
The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences