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
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences