Can non-daytime shifts and physically demanding jobs decrease women’s fertility?

Indeed : heavy lifting, shift work could affect women’s fertility

Women who lift heavy loads at work may experience decreased fertility, and the effect appears stronger among overweight or obese women and older women, according to a new study from Harvard T.H. Chan School of Public Health.

Working non-daytime work schedules may also decrease fertility, the researchers found. 

2017 Study Abstract

Objectives
To explore whether work schedules and physically demanding work were associated with markers of ovarian reserve and response.

Methods
This analysis included women (n=473 and n=313 for ovarian reserve and ovarian response analysis, respectively) enrolled in a prospective cohort study of couples presenting to an academic fertility centre (2004–2015). Information on occupational factors was collected on a take-home questionnaire, and reproductive outcomes were abstracted from electronic medical records. Generalised linear models and generalised linear mixed models were used to evaluate the associations.

Occupational factors and markers of ovarian reserve and response among women at a fertility centre, BMJ, dx.doi.org/10.1136/oemed-2016-103953, 6 February 2017.

Results
Women who reported lifting or moving heavy objects at work had 1.0 fewer total oocytes (p=0.08), 1.4 fewer mature oocytes (p=0.007) and 0.7 fewer antral follicles (p=0.06) compared with women who reported never lifting or moving heavy objects at work. The inverse association between heavy lifting and oocyte yield was stronger in women >37 years and with a Body Mass Index ≥25 kg/m2. Women who worked evening/night/rotating shifts had 2.3 (p<0.001) fewer mature oocytes, on average, compared with women who worked day-only shifts. None of the occupational exposures were associated with day 3 follicle-stimulating hormone or peak oestradiol levels.

Conclusions
Women working non-daytime shifts and those with physically demanding jobs had fewer mature oocytes retrieved after controlled ovarian hyperstimulation. Our results provide insight into possible mechanisms linking these occupational exposures with decreased fecundity.

Association Between the Probability of Autism Spectrum Disorder and Normative Sex-Related Phenotypic Diversity in Brain Structure

Why Autism Affects Boys More than Girls

Key Points

Question
Does the neuroanatomical male brain phenotype carry a higher intrinsic risk for autism spectrum disorder than the female neurophenotype, which could explain the male preponderant prevalence of autism spectrum disorder?

Findings
In this case-control study of 98 adults with autism spectrum disorder and 98 matched neurotypical control individuals, the neurobiological male phenotype was associated with a higher risk for autism spectrum disorder than the female phenotype across the binary categories dictated by biological sex.

Meaning
In addition to genetic and environmental factors, normative sex-related phenotypic diversity should be considered when determining an individual’s risk for autism spectrum disorder.

2017 Study Abstract

Association Between the Probability of Autism Spectrum Disorder and Normative Sex-Related Phenotypic Diversity in Brain Structure, The JAMA Network, doi:10.1001/jamapsychiatry.2016.3990, February 8, 2017.

Image credit Sydney Rae Hass for TIME.

Importance
Autism spectrum disorder (ASD) is 2 to 5 times more common in male individuals than in female individuals. While the male preponderant prevalence of ASD might partially be explained by sex differences in clinical symptoms, etiological models suggest that the biological male phenotype carries a higher intrinsic risk for ASD than the female phenotype. To our knowledge, this hypothesis has never been tested directly, and the neurobiological mechanisms that modulate ASD risk in male individuals and female individuals remain elusive.

Objectives
To examine the probability of ASD as a function of normative sex-related phenotypic diversity in brain structure and to identify the patterns of sex-related neuroanatomical variability associated with low or high probability of ASD.

Design, Setting, and Participants
This study examined a cross-sectional sample of 98 right-handed, high-functioning adults with ASD and 98 matched neurotypical control individuals aged 18 to 42 years. A multivariate probabilistic classification approach was used to develop a predictive model of biological sex based on cortical thickness measures assessed via magnetic resonance imaging in neurotypical controls. This normative model was subsequently applied to individuals with ASD. The study dates were June 2005 to October 2009, and this analysis was conducted between June 2015 and July 2016.

Main Outcomes and Measures
Sample and population ASD probability estimates as a function of normative sex-related diversity in brain structure, as well as neuroanatomical patterns associated with low or high ASD probability in male individuals and female individuals.

Results
Among the 98 individuals with ASD, 49 were male and 49 female, with a mean (SD) age of 26.88 (7.18) years. Among the 98 controls, 51 were male and 47 female, with a mean (SD) age of 27.39 (6.44) years. The sample probability of ASD increased significantly with predictive probabilities for the male neuroanatomical brain phenotype. For example, biological female individuals with a more male-typic pattern of brain anatomy were significantly (ie, 3 times) more likely to have ASD than biological female individuals with a characteristically female brain phenotype (P = .72 vs .24, respectively; χ21 = 20.26; P < .001; difference in P values, 0.48; 95% CI, 0.29-0.68). This finding translates to an estimated variability in population prevalence from 0.2% to 1.3%, respectively. Moreover, the patterns of neuroanatomical variability carrying low or high ASD probability were sex specific (eg, in inferior temporal regions, where ASD has different neurobiological underpinnings in male individuals and female individuals).

Conclusions and Relevance
These findings highlight the need for considering normative sex-related phenotypic diversity when determining an individual’s risk for ASD and provide important novel insights into the neurobiological mechanisms mediating sex differences in ASD prevalence.

The Concern about Overdiagnosis

A clear insight about over diagnosis in less than 3 mns

Video published on 19 Nov 2016 by Show More Spine.

Paul Glasziou’s Interview by Alan Cassels at Preventing Overdiagnosis Conference 2016 in Barcelona, Spain.

Watch more videos about overdiagnosis on YouTube.

Bioaccumulation of Antibiotic Pollution in Marine Food Webs

Antibiotic Pollution in Marine Food Webs in Laizhou Bay, North China: Trophodynamics and Human Exposure Implication

2017 Study Abstract

Little information is available about the bioaccumulation and biomagnification of antibiotics in marine food webs.

Here, we investigate the levels and trophic transfer of 9 sulfonamide (SA), 5 fluoroquinolone (FQ), and 4 macrolide (ML) antibiotics, as well as trimethoprim in nine invertebrate and ten fish species collected from a marine food web in Laizhou Bay, North China in 2014 and 2015.

All the antibiotics were detected in the marine organisms, with SAs and FQs being the most abundant antibiotics. Benthic fish accumulated more SAs than invertebrates and pelagic fish, while invertebrates exhibited higher FQ levels than fish.

Antibiotic Pollution in Marine Food Webs in Laizhou Bay, North China: Trophodynamics and Human Exposure Implication, Environmental Science & Technology, DOI: 10.1021/acs.est.6b04556, January 20, 2017.

Generally, SAs and trimethoprim biomagnified in the food web, while the FQs and MLs were biodiluted. Trophic magnification factors (TMF) were 1.2–3.9 for SAs and trimethoprim, 0.3–1.0 for FQs and MLs. Limited biotransformation and relatively high assimilation efficiencies are the likely reasons for the biomagnification of SAs. The pH dependent distribution coefficients (log D) but not the lipophilicity (log KOW) of SAs and FQs had a significant correlation (r = 0.73; p < 0.05) with their TMFs.

Although the calculated estimated daily intakes (EDI) for antibiotics suggest that consumption of seafood from Laizhou Bay is not associated with significant human health risks, this study provides important insights into the guidance of risk management of antibiotics.

Evidence that bisphenol S crosses the human placenta

Common BPA alternative, BPS, crosses into placenta

Bisphenol S (BPS), found in baby bottles, personal care products and thermal receipts, is a replacement chemical for BPA and was introduced when concern was raised about possible health effects of that plastic compound.

As with BPA, there is evidence that BPS is an endocrine disruptor. Canadian and Chinese scientists have found the “first evidence” that BPS can cross the human placenta.

2017 Study Abstract

Human studies show associations between maternal bisphenol A (BPA) exposure and developmental effects in children, yet biomonitoring of BPA metabolites in maternal and fetal serum remains limited, and less is known for BPA alternatives. BPA-glucuronide, BPA-sulfate, and bisphenol S (BPS) were quantified in 61 pairs of maternal and cord sera from Chinese participants.

Bisphenol A Metabolites and Bisphenol S in Paired Maternal and Cord Serum, Environmental Science & Technology, DOI: 10.1021/acs.est.6b05718, January 22, 2017.

Total BPS was only detectable in four maternal (<0.03–0.07 ng/mL) and seven cord sera (<0.03–0.12 ng/mL), indicating low exposure but providing the first evidence that BPS crosses the human placenta. Total BPA metabolites in cord serum were significantly higher than in maternal serum (p < 0.05), suggesting that these may be formed in the fetus or cleared more slowly from the fetoplacental compartment. Unlike the pharmacokinetic results from controlled oral exposure studies in which BPA-glucuronide is the major BPA metabolite, here, BPA-sulfate was the dominant metabolite (GM: 0.06 and 0.08 ng/mL), significantly higher than BPA-glucuronide (GM: 0.02 and 0.04 ng/mL) (p < 0.01) in both maternal and cord sera. Moreover, the proportion of BPA-sulfate increased with total BPA.

These are the first human data for BPA metabolites in paired maternal and cord serum, and results suggest that the human fetus and pregnant mother have unique exposure to BPA metabolites. Direct analysis of BPA metabolites in serum provides complementary information for evaluating early life-stage exposure and risks of BPA.

The European Chemicals Agency’s role in the EU-wide classification of glyphosate

What is happening with glyphosate in the EU?

Video published on 7 February 2017 by EUchemicals.

Glyphosate is one of the most widely used substances in pesticides. The authorisation for using it in the EU has expired and authorities are deciding whether to renew it for a further 15 years.

The European Commission has in the meantime extended the authorisation temporarily until the end of 2017 while waiting for the classification of the substance by the European Chemicals Agency (ECHA).

Corporate Europe Action

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EurActiv Statement

Read the press release here.

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Join the initiative here.

Science Mag Position

Read the press release here.

EDCs, Pesticides and EU Lobbying…
  1. The Manufacture of a Lie.
  2. A Denial of the State of the Science.
  3. The Interference of the United States.
  4. The Discreet but Major Gift to the Pesticides Lobby.

Increases in synthetic chemical production, and diversification of pharmaceuticals and pesticides, outpace known agents of global change

Production of synthetic chemicals is far outpacing the ability of scientists to study their effects

According to a new analysis in the journal Frontiers of Ecology and Environment, the rate of increase in the production and diversification of pharmaceuticals and pesticides exceeds that of most previously recognized agents of global change, such as habitat destruction and even CO2 emissions. But, reports the analysis — by Emily Bernhardt of Duke University and colleagues — the amount of scientific attention being paid to them, and particularly their possible ecological impacts, is disproportionately low.

2017 Study Abstract

Image credit The Ecological Society of America via Science X network.

Though concerns about the proliferation of synthetic chemicals – including pesticides – gave rise to the modern environmental movement in the early 1960s, synthetic chemical pollution has not been included in most analyses of global change. We examined the rate of change in the production and variety of pesticides, pharmaceuticals, and other synthetic chemicals over the past four decades. We compared these rates to those for well-recognized drivers of global change such as rising atmospheric CO2 concentrations, nutrient pollution, habitat destruction, and biodiversity loss. Our analysis showed that increases in synthetic chemical production and diversification, particularly within the developing world, outpaced these other agents of global change. Despite these trends, mainstream ecological journals, ecological meetings, and ecological funding through the US National Science Foundation devote less than 2% of their journal pages, meeting talks, and science funding, respectively, to the study of synthetic chemicals.

More Information

  • Synthetic chemicals as agents of global change, Frontiers of Ecology and Environment, 24 January 2017.
  • Chemical Pollution Is Soaring Faster Than We Can Measure It, seeker, Feb 1, 2017
  • SYNTHETIC CHEMICALS UNDERSTUDIED DRIVERS OF ENVIRONMENTAL CHANGE, Nicholas School of the Environment, Duke University, January 24, 2017.
  • Science Is Falling Woefully Behind in Testing New Chemicals, smithsonianmag, FEBRUARY 3, 2017.
  • Synthetic chemicals: Ignored agents of global change, phys.org, January 24, 2017.

Prenatal BPA exposure alters our natural ability to control appetite

Mouse study sheds light on how endocrine-disrupting chemical increases obesity risk

Washington, DC – An expectant mother’s exposure to the endocrine-disrupting chemical bisphenol A (BPA) can raise her offspring’s risk of obesity by reducing sensitivity to a hormone responsible for controlling appetite, according to a mouse study published in the Endocrine Society’s journal Endocrinology.

BPA is a chemical found in a variety of food containers, including polycarbonate plastic water bottles and can linings. BPA can interfere with the endocrine system by mimicking estrogen, one of the main sex hormones found in women. Research indicates BPA exposure is nearly universal. More than 90 percent of people tested in population studies had detectable levels of BPA and compounds produced when it is metabolized by the body in their urine.

As of 2014, nearly 100 epidemiological studies had been published tying BPA to various health problems, according to the Society and IPEN’s Introduction to Endocrine-Disrupting Chemicals.

Prenatal bisphenol A exposure weakens body’s fullness cues, The Endocrine Society News Room, February 07, 2017.

Image credit Owen and Aki.

The new study – Perinatal Exposure to Bisphenol-A (BPA) Delays the Postnatal Leptin Surge in Male and Female CD-1 Mice – found mice born to mothers exposed to BPA were less responsive to the hormone leptin, which is sometimes called the satiety hormone. Leptin helps inhibit the appetite by reducing hunger pangs when the body does not need energy. The hormone sends signals to the hypothalamus region of the brain to suppress the appetite.

“Our findings show that bisphenol A can promote obesity in mice by altering the hypothalamic circuits in the brain that regulate feeding behavior and energy balance.
Low level prenatal exposure to BPA delays a surge of leptin after birth that allows mice to develop the proper response to the hormone. BPA exposure permanently alters the neurobiology in the affected mice, making them prone to obesity as adults.”

said the study’s senior author, Alfonso Abizaid, Ph.D., of the Department of Neuroscience at Carleton University in Ottawa, Canada.

To examine how BPA can encourage the development of obesity, the researchers fed pregnant mice BPA in their food. The mice were exposed to doses of BPA that are lower than levels deemed safe by the U.S. Food and Drug Administration and Health Canada. Once the mice gave birth, the researchers gave their offspring injections of leptin at various intervals and then examined their brain tissue and analyzed their blood to gauge the response to the hormone.

Other pregnant mice were not exposed to any chemicals or were exposed to an estrogen chemical called diethylstilbestrol (DES), so their young could be compared to those born to mice that were exposed to BPA. All the mice were fed a control diet to eliminate differences in food intake.

Newborn mice typically exhibit a surge of leptin when they are eight days old that programs the hypothalamus circuits to respond to fullness cues. The study found that animals exposed to BPA experienced this surge two days late, and mice exposed to DES never had a surge of leptin. When they were treated with leptin over the course of two days, control animals that weren’t exposed to either chemical lost more weight than BPA- or DES-exposed mice.

In addition, researchers found that mice exposed to BPA before birth had reduced fiber density and brain activity in the hypothalamus circuits involved in regulating energy expenditure.

“This study improves our understanding of how BPA can disrupt the endocrine system in a manner that raises the risk of obesity in animals.
Since BPA has also been linked to obesity in humans, people need to be aware that environmental factors can lead to increased susceptibility to obesity and cardio-metabolic disorders.”

Abizaid said.

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Mother’s diet in pregnancy may have lasting effects for offspring

Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults

A poor diet during pregnancy can cause biological changes that last throughout life, according to research from Imperial College London.

The study Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults, published this week in the journal Cell Reports, showed that when pregnant mice were fed a diet deficient in protein this interfered with the expression of genes within the embryo that are known to be important for healthy growth.

The impact of adversity, such as a poor diet in early life, and whether this might cause lasting effects has long intrigued scientists. There have been suggestions that the children of women pregnant during famines, for example, may suffer harmful effects later in life. This new study offers a new way to visualise such effects and possible ways to counter these.

The researchers, at the Medical Research Council London Institute of Medical Sciences (MRC LMS), developed novel imaging techniques that enabled them to visualise genes as they were switched “on” or “off” in mouse embryos as they grew. This enabled the team to see exactly where alterations in response to maternal diet were happening and, crucially when during pregnancy key changes took place.

Understanding how genes are controlled and kept “on” or “off” is a relatively new field of science known as “epigenetics”. This is the first time such epigenetic effects have been visualised during development in this way, using a simple but powerful bioluminescent imaging approach.

The team attached enzymes from fireflies (luciferase) or bacteria (beta-galactosidase) onto the gene they were studying, and watched how this produced a glow as the gene was turned “on” in mice.

The research focused on a group of genes called “imprinted” genes, and on one in particular known as Cdkn1c. Imprinted genes are intriguing because although a copy of the gene is inherited from each parent, as usual, only one of these copies is active. The other copy is kept idle, or “silenced”. In the case of Cdkn1c, only the copy inherited from the mother is active.

Using their new visualising technique, the team showed that if a mouse carried the copy of the gene from the father, which is “silenced”, then it could not be seen. If they used either diet or drugs to re-activate it, they were able to see the gene glow. The researchers expect that this new way to “see” when imprinted genes are active or silent will prove valuable for many other scientists who are investigating epigenetic effects in our bodies.

Imprinted genes

Dr Mathew Van de Pette, a lead author based at the MRC LMS, said:

“There are around 100 imprinted genes, about 0.4% of the total in the genome, and most appear to have their greatest impact during pregnancy.
The pattern by which imprinted genes are ‘set’ in early life plays an important part in the development of healthy offspring. If a gene is ‘miss-set’ then problems may occur later.
We found that mice fed a low protein diet in pregnancy produced offspring in which the father’s copy of the gene became active and stayed that way. This demonstrates a clear link between early life adversity and later life outcomes.”

Professor Amanda Fisher, who led the study and is director of the MRC LMS, said:

“We were surprised that this change in diet permanently affected the expression of this imprinted gene.
Our work suggests there may be a window of vulnerability when diet can indeed have an effect, and that once these genes are set, they’re set for life.
The good news is that we’ve also shown that it’s possible to avoid this with a normal diet.”

Kate Wighton, Imperial College London newssummary, 03 February 2017.

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