Breaking Research

U of T-led study finds link between 'ADHD-like symptoms' and high fluoride levels during pregnancy

Christopher.Sorensen — Wed, 10 Oct 2018 15:37:56 +0000

U of T-led study finds link between 'ADHD-like symptoms' and high fluoride levels during pregnancy

Christopher.Sorensen Wed, 10/10/2018 - 11:37

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The study analyzed data from 213 mother-child pairs in Mexico City (Photo by Lino Mirgeler/picture alliance via Getty Images)

Nicole Bodnar

Topic

Global Lens

Breaking Research

Child Development

Dalla Lana School of Public Health

Fluoride

Higher levels of urinary fluoride during pregnancy are associated with more ADHD-like symptoms in school-age children as reported by parents, according to a new study by researchers at the ��Ƶ and other universities.

The findings, published today in Environment International, stem from the researchers’ analysis of data from 213 mother-child pairs in Mexico City that were part of the Early Life Exposures in Mexico to Environmental Toxicants project. The project recruited pregnant women from 1994 to 2005 and has continued to follow the women and their children ever since.

“Our findings are consistent with a growing body of evidence suggesting that the growing fetal nervous system may be negatively affected by higher levels of fluoride exposure,” said Morteza Bashash, the study’s lead author and a researcher at U of T’s Dalla Lana School of Public Health.

Tap water and dental products have been fluoridated in communities in Canada and the United States (as well as milk and table salt in some other countries) by varying amounts for more than 60 years to prevent cavities. In recent years, however, fierce debate over the safety of water fluoridation — particularly for children’s developing brains — has prompted researchers to explore the issue and provide evidence to inform national drinking water standards.

The study's research team — including experts from the ��Ƶ, York University, the National Institute of Public Health of Mexico, University of Michigan, Indiana University, the University of Washington and Harvard University — analyzed urine samples that had been obtained from mothers during pregnancy and from their children between six and 12 years of age to reconstruct personal measures of fluoride exposure for both mother and child.

The researchers then analyzed how levels of fluoride in urine related to the child’s performance on a variety of tests and questionnaires that measure inattention and hyperactivity, and provided overall scores related to ADHD, or Attention Deficit Hyperactivity Disorder. Analyses were adjusted for other factors known to impact neurodevelopment, such as gestational age at birth, birthweight, birth order, sex, maternal marital status, smoking history, age at delivery, education, socioeconomic status and lead exposure.

“Our findings show that children with elevated prenatal exposure to fluoride were more likely to show symptoms of ADHD as reported by parents,” said Bashash. “Prenatal fluoride exposure was more strongly associated with inattentive behaviours and cognitive problems, but not with hyperactivity,”

This work builds off of previous research the team published on this population demonstrating that higher levels of urine fluoride during pregnancy are associated with lower scores on tests of IQ and cognition in the school-age children.

ADHD is the most common psychiatric disorder diagnosed in childhood, affecting between five and nine per cent of all school-aged children.

“The symptoms of ADHD often persist into adulthood and can be impairing in daily life,” said Christine Till, an associate professor of psychology at York University and co-author on the study.

“If we can understand the reasons behind this association, we can then begin to develop preventive strategies to mitigate the risk,” said Till, who is also the principal investigator of another National Institutes of Health (NIH)-funded grant examining fluoride exposure in a large Canadian sample of pregnant women.

The study was funded by the National Institute of Environmental Health Sciences, part of the NIH.

Cowabunga! U of T Scarborough researchers team up with Parks Canada to save the turtles

vzaretski — Thu, 14 Jul 2016 19:28:23 +0000

Cowabunga! U of T Scarborough researchers team up with Parks Canada to save the turtles

vzaretski Thu, 07/14/2016 - 15:28

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Photo by Joren Romaniuk

Don Campbell

Author legacy

Don Campbell

Topic

Breaking Research

UTSC

Ecology & Evolutionary Biology

Researchers at U of T Scarborough are teaming up with Parks Canada and the Toronto Zoo to help a threatened species rebound in the Rouge National Urban Park.

A total of 36 Blanding turtles – many of them fixed with small radio transmitters – were recently released into a restored wetland section of the park. They will be tracked by U of T Scarborough students to learn more about the turtles’ behaviour in the wild.

“We want to know how the turtles use the restored wetlands, if it offers a suitable wintering habitat and to find the spots where they are most successful,” says Shannon Ritchie, a master’s student in the ecology and evolutionary biology program at U of T Scarborough.

See the CBC story

The odds are certainly stacked against the turtles. A loss of habitat, high predation from skunks and raccoons and a tendency to travel long distances on land to find a suitable nesting spot puts them at an increased risk of being killed. They also can’t start reproducing until around age 12 to 15.

“When you lose one turtle it can take a long time to replace it. They have a very low chance of survival and it’s why conservation efforts are so important,” says Ritchie, who is pictured below.

Named in honour of American naturalist Dr. William Blanding, the Blanding turtle is easily recognizable by its buggy-eyes and bright yellow chin that makes it look like its smiling. It’s medium-sized by turtle standards with an average shell length of 18 to 23 cm and can live to be as old as 80, although finding one in the wild as old as 60 is rare, notes Ritchie. In the wild they can be found in pockets across Ontario and northern New York State.

The turtles released into the Rouge are the product of the Toronto Zoo’s Headstarting program. The program takes eggs from nests in precarious locations with a low chance of survival like farmers’ fields and construction sites to the zoo where they are incubated. The turtles are then raised for two years in the zoo’s husbandry area before being released.

Ritchie says that the turtles are released when they’re “the size of a medium potato,” which is just large enough to deter most predators.

The wetlands the turtles will be released into were restored with the help of the Toronto and Region Conservation Authority. The goal of the project is to also gain as much valuable information on the best conservation strategies and to help with future preservation efforts.

“We want to see which habitats the turtles prefer during certain times of the year, but also if they’re able to learn a new ecological system and if that behaviour is exploratory or knowledge based,” says Associate Professor Nick Mandrak, an expert on biodiversity and conservation.

Tisha Tan, a student in the conservation and biodiversity stream of UTSC’s professional master’s of environmental science program, will also be looking at whether turtles released directly into their new environment behave differently than those that are acclimatized to their environment first before being released.

“This is where the partnership between the university and the Toronto Zoo really comes into play – we’re doing research that will help inform future decisions related to the program,” adds Mandrak.

Blanding turtle outfitted with a small radio transmitter. Photo by Joren Romaniuk

Don Campbell is a writer with U of T Scarborough

EgyptAir 804: U of T forensic expert explains what we know so far

krisha — Mon, 30 May 2016 15:35:06 +0000

EgyptAir 804: U of T forensic expert explains what we know so far

krisha Mon, 05/30/2016 - 11:35

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CAIRO, EGYPT - EgyptAir employees and relatives of the victims light candles for 66 victims of EgyptAir flight MS804 crash in front of Opera Building in Cairo, Egypt on May 26, 2016. (Photo by Ibrahim Ramadan/Anadolu Agency/

Noreen Ahmed-Ullah

Author legacy

Noreen Ahmed-Ullah

Topic

Global Lens

Breaking Research

Since EgyptAir’s Flight 804 vanished, carrying 66 passengers and crew on board, investigators have been busy looking for human remains and debris in the Mediterranean Sea.

The search continues for the plane’s black box recorders, which could explain what brought down the Paris-to-Cairo flight – the third crash for EgyptAir since 1999. The black boxes are believed to be lying in up to 3,000 metres of water.

Egyptian authorities have said the possibility of a terror attack is stronger than technical failure. U of T News spoke with forensic engineering expert Doug Perovic, of the department of materials science and engineering on what the recovered debris can tell us about the final moments of the flight and why he believes speculation an explosion took place is premature.

Why have some investigators said they believe an explosion took place on EgyptAir?

The relatively small size of fragments of body parts and debris from the plane interior that have been recovered to date has led to speculation that the aircraft suffered a mid-air catastrophic explosion. Such a conclusion is premature and representative of two common forms of bias in forensic investigations: (i) ‘data bias’ associated with insufficient data collection and analysis that can bias findings and conclusions and/or (ii) ‘confirmation/expectation bias (i.e. tunnel vision)’ resulting from the subconscious tendency of those desiring a particular outcome to search for supporting evidence and/or ignoring or reinterpreting contradictory information. In the world of interpretation, subconsciously many tend to find what they are looking for.

Egyptian experts say that the 80 pieces that have been found so far are very small. What will that mean to investigators?

The fragments collected thus far all contain useful evidence that can eventually help put the puzzle together. However, the small size of the collected fragments does not prove a mid-air explosion occurred. Fragmentation of components can also occur during excessively high speed descent of an intact aircraft and/or following a high-speed impact with the ocean surface. Chemical analysis of unexpected residues detected on the collected fragments or x-ray radiography of body parts could confirm whether an explosion occurred on-board. However, recovery and subsequent structural and chemical analyses of the aircraft fuselage are required in determining the cause of the crash.

Below: Some of the passengers' belongings and parts of the wreck of found north of Alexandria on May 21, 2016 (photo © by Anadolu Agency/Egyptian Armed Forces / Handout /Getty Images)

How important is the black box?

It is unfortunate that aircraft are still not legislated to live-stream all critical data describing the exact position and operating conditions of an aircraft. This technology has existed for years and would in most cases preclude the need for time-consuming and expensive searches for black boxes to obtain critical data. The search for the flight data recorder and cockpit voice recorder black boxes will require extensive deployment of deep sea diving equipment to detect the sonar pings emanating from the black boxes. In light of the depth and significant topographical relief of the Mediterranean Sea floor in the presumed location of the fuselage, the task of locating the black boxes within the 30-day lifetime of the sonar ping batteries is daunting. Once found the black boxes will reveal operational data from the aircraft and voice transmissions from the flight deck that provide critical information for the determination of the sequence of events leading to loss of control of the aircraft.

Egyptian officials have said they believe terrorism is a more likely explanation than equipment failure.

At this time there is insufficient information to differentiate between a deliberate terrorist act and mechanical failure. Although most media coverage has focused on terrorism, it is noteworthy that the first ACARS fault obtained from the aircraft prior to its disappearance was smoke/fire from the co-pilot’s window, followed immediately by smoke/fire in the adjacent lavatory and then smoke/fire in the avionics bay located below. The American Federal Aviation Administration released a directive in 2003 regarding possible delamination of the heated gold interlayer used for defogging/de-icing of the cockpit windows of Airbus A320 aircraft. It is possible that a delamination failure occurred in the window leading to a capacitance charge overload causing a fire and ultimately loss of control of the aircraft.

Greek defense officials have said the plane changed direction before it disappeared but Egyptian officials say they did not observe this. Why the discrepancy?

It is likely that both Greek and Egyptian radar surveillance observations were correct. While in Greek airspace the aircraft was likely sufficiently close in proximity for multiple radar signatures to be obtained giving rise to a higher resolution tracking of the aircraft flight path. When Egyptian radar detected the aircraft it was much further away and likely not capable of tracking the aircraft trajectory with the same accuracy as air traffic control in Greece.