Is DDT a time-bomb behind the obesity epidemic? | Grist

ddt_adMichael Skinner didn’t start the experiment with the hypothesis that he’d find a connection between the insecticide DDT and obesity.

“We didn’t expect to find that,” he said. “In fact, the frequency of obesity really came as a surprise.”

Skinner, a scientist at Washington State University, wanted to take a close look at the way DDT affected inheritance. So his team injected DDT into pregnant rats and watched first their children, and then their grandchildren (or is it grandrats?). It was only in the third generation, the great-grand-rat, that they saw it: Fully half of these rats were obese. The implication is that the same thing could be happening with humans.

Michael Skinner
Michael Skinner.

“Is there a correlation between the fact that we were all exposed to DDT in the 1950s for 10 years, and the fact that we are now seeing high levels of obesity?” Skinner asked. His work suggests that there could be.

Of course, the more immediate cause of obesity is too many calories. But there may be more going on here than too much food. Humans are getting fat, so are our pets, so are wild animals. There’s a trend toward obesity in nearly every species scientists have studied.

Of course it’s too early to lay the blame on DDT. This study simply raised the possibility. But the findings are plausible.

“I do believe that the observed obesity is real,” emailed Andrea Gore, a professor of pharmacology and toxicology at the University of Texas Austin. Other experiments have already shown that endocrine-disrupting chemicals can cause obesity generations after exposure, Gore said.

Skinner had already seen that he could trigger the inheritance of disease with various chemicals. There’s a narrow window during the gestation, where an exposure to lots of things can cause heritable epigenetic changes.

“The majority of things we’ve tested came up positive,” he said.

So the obvious question: Is this a problem specific to DDT, or would we have seen similar results if Skinner’s team had decided to inject the rats with vitamin C? In other words, is this about the chemical, or just the timing of the exposure?

If the DDT had caused kidney disease, Skinner said, he would have been reassured. A lot of things seem to have epigenetic effects that lead to kidney disease. But obesity is unusual — that suggests a problem with DDT itself, Skinner said.

Skinner started this experiment after the World Health Organization lifted the ban on DDT to help fight malaria. That was a good decision based on the available information, Skinner said, but no one had looked to see if DDT had an effect on subsequent generations. “On the one hand, there are 2 million deaths per year in Africa from malaria. On the other hand, we’re looking at the possibility of metabolic disease in every generation to come,” Skinner said.

The word “possibility” there is key. This wasn’t a risk assessment study, and we don’t know if we’d see something similar in humans from environmental exposure to DDT, as opposed to direct injection. But this study should give pause to the people arguing to reintroduce DDT to places even without a malaria problem, Skinner said. It’s now being used in France, among other places. And once you spray DDT, it’s out there for a long time.

“If you go to any river in the U.S., and push your finger down into the mud one or two inches, the primary contaminant you will find there is DDT,” Skinner said. The stuff just takes a really long time to break down, and Skinner’s research suggests that its effects could last much longer.


Study finds no link between kids' obesity and DDT, PCBs …

July 4, 2013

U.S. children who were exposed in the womb to high levels of DDT, PCBs and other chlorinated chemicals in the 1960s were not more likely to be obese, according to new research.

One substance, dieldrin, was linked to higher odds of obesity in children but the number of children studied was small.

Fhardseen/flickr Multiple causes of childhood obesity may include prenatal exposure to chemicals.

It is the largest study examining the link between organochlorine chemicals and childhood obesity, and the first to associate obesity with prenatal exposure to the pesticide dieldrin. Previous studies have reached conflicting conclusions.

Organochlorines were widely used as pesticides and industrial compounds in the 1940s through 1970s. Most uses have been banned for decades. However, traces of these chemicals are still found in most people’s bodies today because they persist in the environment and accumulate in fatty tissues.

Childhood obesity is an increasing problem worldwide. In the United States, 4 percent of children aged 6 to 11 were obese in the early 1970s compared with 20 percent in 2008. Researchers have been examining the role that prenatal exposure to potentially hormone-altering chemicals – such as organochlorines – may play.

The epidemiologists used data from the U.S. Collaborative Perinatal Project, which enrolled pregnant women from 1959-1965. The women’s blood was measured in their third trimester for DDT, polychlorinated biphenyls (PCBs) and other chlorinated chemicals. Then the researchers checked records for 1,915 of the women’s children to determine how many were obese at the age of 7.

Prenatal exposure to all but one of the chemicals was not associated with obese or overweight children. However, for dieldrin, children in the two groups of highest exposure were 3.6 and 2.3 times more likely to be obese than those in the lowest exposure group.

Only 89 children were in the two highest exposure groups. “The suggestive association between dieldrin and childhood obesity was perhaps a chance finding given the number of analyses we performed,” the authors wrote in the paper published in Environmental Health Perspectives.

Dieldrin was widely used as a pesticide from about 1950 to 1974 but was banned from almost all uses in the United States in 1985, according to the U.S. Environmental Protection Agency.

The pregnant women in this study had much higher levels of all the chemicals tested (hexachlorocyclohexane, DDE, DDT, dieldrin, heptachlor epoxide, hexachlorobenzene, trans-nonachlor, oxychlordane and PCBs) than people do today.

The researchers controlled for mothers’ race, education, pre-pregnancy weight, smoking status and the child’s birth order.

Previous research linking the chemicals to children’s body weight has been inconsistent. DDE exposure was linked to a higher body mass index for children, according to a 2011 study, but the link was dependent upon maternal smoking. HCB exposure was linked to obesity and higher body mass index for children in a 2008 study. The children were exposed to higher levels than in the current study.

On the contrary, PCBs were linked to decreased weight among exposed children in studies in 2002 and 2006. This association was not found in the present study.

It is unclear how organochlorine chemicals might affect a child’s body weight. But previous research has suggested that they could alter the hormones that regulate growth or alter the functioning of the central nervous system.

Most studies have focused on high levels of exposure. In light of this, the authors of the current study said they could not rule out the possibility that prenatal exposure to low levels of organochlorines could spur obesity. Some research has shown that small doses of hormone-like substances can have effects that large doses do not.

The study was a collaboration of scientists from Mexico’s National Institute of Public Health, the U.S. Centers for Disease Control and Prevention, the National Institute of Environmental Health Sciences and Ohio State University.

 

Chemicals found responsible for early puberty in girls

A recent study has found that certain chemicals found in the shower curtains, food cans and toys are the triggering agents for early puberty. According to www.dailymail.co.uk, these chemicals are also responsible for posing increased risk of diabetes and cancer. The study was conducted in the wake of concern over the decreasing puberty age in girls which has seen a fall from ten years and three months to almost nine years of age now at the end of one generation.
As per www.blogs.monografias.com, the study has revealed that three chemicals are to be blamed for a disrupted timing of the age of puberty namely- phytoestrogens, phenols and phthalates. The test was conducted on about 1,151 girls who were examined for the concentration of the chemicals in their bodies. It was found that girls who had higher amounts of these chemicals reached their puberty earlier than others who had moderate amounts of these chemicals.
In addition, findings suggested that girls who were overweight also recorded for early puberty than their healthy counterparts.  While Phthalates are found in cosmetics, Phenols are used in the production of food cans and Phytoestrogens are substances found in bread, soya and nuts. Dr Mary Wolff, one of the researchers concluded ‘While more research is needed, these data are an important first step in continuing to evaluate the impact of these common environmental agents in putting girls at risk.’
Images: http://www.sxc.hu/photo/967632, http://www.sxc.hu/photo/725159

Chemicals in furniture could cause infertility

Will you look at your old table or curtains the same way after knowing that scientists have household products to contain chemicals that can cause infertility?

A study has found that flame retardant chemicals found in some furniture causes delay and difficulties in women becoming pregnant. The study, conducted by UC Berkley, found that women with high levels of the chemicals, called polybrominated diphenyl ethers (PBDEs), were between 30 and 50 percent less like to conceive every month than women with low levels, the New York Daily Post reports.

University of Berkley Professor Kim Harley said: “When the analysis was limited to women who were actively trying to become pregnant, we found that they were half as likely to conceive in any given month if they had high levels of PBDE in their blood.

“We aren’t looking at infertility, just sub-fertility, because all the women in our study eventually became pregnant.

“Had we included infertile couples in our study, it is possible that we would have seen an even stronger effect from PBDE exposure.”

Professor Harley added that it is suspected PBDEs affect the levels of sex hormones, which then affected the chances of falling pregnant, telegraph.co.uk reports.

These chemicals were reportedly common in furniture from the 1970s, including carpets, electric appliances, sofas and plastics. The Telegraph reports these chemicals are inhaled and are then stored in the fat cells.

While many of these chemicals are no longer in common use, we still need to be aware we will probably be affected by them for a long time, Professor Harley says.

“PBDEs are present in many consumer products, and we know they leach out into our homes. In our research, we have found that low-income children in are exposed to very high levels of PBDEs, and this has us concerned about the next generation.”

That’s not even mentioning the new chemicals in new products out on the market, of which, Professor Harley says, we know even less.

Several celebrities have had fertility problems, and reverted to treatments, including IVF and Artificial Insemination.

Celebrities who have had IVF include Octomom.

Image: http://commons.wikimedia.org/wiki/File:Pregnant_woman2.jpg

Chemotherapy

Chemotherapy essentially means a chemical treatment. It is most wifely used to treat cancer in patients. Chemotherapy is a cocktail of chemicals that is administered to a patient in order to kill cancer cells directly, although it kills healthy cells as well. There are currently more than 100 chemicals in use for chemotherapy, with many more currently being investigated.

Chemotherapy, as said, is used most frequently for killing cancer cells, however it may also be used in order to shrink the size of a tumor , relieve pain and control the growth of a tumor when other treatment (such as surgery, radiation) is not possible.

Cancer patients’ cells do not split and reproduce in a natural manner: those cells affeted keep splitting and forming new cells uncontrollably. Chemotherapy is administered here in order to prevent the diseased cells from dividing, effectively preventing more diseased cells from being produced in the body. Unfortunately, also healthy cells can be affected in the process.

There is a wide variety of different manners in which patients may receive chemotherapy. While some may obtain oral medication, others will receive injections (intramuscular), or intravenous chemotherapy treatments, and so forth. One method that is used frequently  is one where a catheter is inserted into a vein of the patient, usually in the neck or chest, that reaches the heart, so that when the chemicals are administered, they travel straight to the heart and are then pumped all over the rest of the body. To read about the various methods through which a chemotherapy may be administered, please click here.

How long a patient will receive chemotherapy is dependant on many different factors, including the type of cancer, the degree of how far the cancer has developed, whether it has spread to other parts of the body, and what chemicals and type of chemotherapy are used. A single sitting of chemotherapy may take minutes, hours or days, and may be repeated weekly, bi-weekly or monthly. A cycle of chemotherapy (usually determined over a period of a month – even if there are two or four sessions in a month) is repeated once or twice. Some patients, however, may receive chemotherapy for up to a year.

Because the patient receives a high dosage of chemicals to prevent cells from splitting, there are several side effects that may occur, including:

  • pain
  • nausea and/or vomiting
  • diarrhea or constipation
  • water retention
  • hair loss
  • memory loss
  • impotence (sexual)
  • anemia
  • weight loss/gain
  • as the immune system is weakened, a patient may endure sepsis and other forms of infection

For more information about chemotherapy, please click here.

Some celebrities who have been diagnosed with cancer and received chemotherapy include Patrick Swayze, Melissa Etheridge, Olivia Newton-John, Sharon Osbourne, Kylie Minogue, Lance Armstrong,  and Farrah Fawcett.