Absolutely fascinating study on environmental chemicals and their impact on our children. A halving of sperm counts in the span of just one generation? A good reminder that we all need to be more aware of what we expose our children to –
‘THERE are 80,000 chemicals in our environment that we are exposed to every day. You cannot avoid it. They’re in the water we drink, the vegetables we eat. We all try and wash fruit and salads, but you’re not going to wash away the pesticides completely. And then there are plastics: with every can of Coke you drink, that can is lined by ‘plasticisers’ that soften the metal, and all that leaches out . . .”
It sounds extreme, but these aren’t the words of a crackpot, a scare-monger, a conspiracy theorist – they’re the words of Prof Ieuan Hughes, head of paediatrics at Cambridge University, and chair of one of the world’s most important research projects, the Cambridge Baby Growth Study (CBGS).
Now in its 11th year, this vast study has tracked 2,400 local babies from gestation to 2 years of age, to find out just how the environment affects them – and, consequently, all of us.
“The background was that sperm counts were declining in the western world,” explains Prof Hughes. “Over a generation they had declined by 50 per cent, which is a huge change. And alongside that, the incidence of testes cancer, which is a cancer that occurs in young men, had gone up quite dramatically.”
Other evidence suggested that abnormalities in baby boys’ genitalia were increasing, particularly ‘undescended testes’ (whereby at birth, the testicles remain in the abdomen rather than dropping into the baby’s scrotum).
“And testes cancer itself is increased in men who had undescended testes as a baby,” adds Prof Hughes.
“So then somebody said: ‘Well hang on, we’ve got a low sperm count, we’ve got testes cancer going up, we’ve got undescended testes increasing: is there a common denominator here that explains all this? Has anything changed in the environment in which we live?’
“So that’s how the so-called ‘endocrine disruptor’ theory came out: endocrine disruptors are chemicals in the environment that disrupt our endocrine system – the hormones we need to make everything work properly.”
And so, back in 2001, Prof Hughes and his team set about recruiting pregnant mothers. Willing participants donated blood, and were asked to record everything they ate and drank, as well as toiletries and other chemicals they used at home. Then, when their baby was born, the placenta, cord blood, breast milk and other samples were taken and stored.
Meanwhile the babies were examined and measured at birth, and again every three to six months until they turned 2. In addition, the mums kept painstakingly accurate food diaries, recording everything their little one ate and drank.
The statistics were immediately surprising: “The first thing we looked at was undescended testes, and we found that the rate was between 6 and 7 per cent. A similar study had been done in the 1960s, using very similar methods we could compare, and we had seen a doubling in the rate in that time.”
Prof Hughes admits he was shocked: “When you think nearly 7 per cent of all boys have undescended testes, that’s a huge percentage – and those boys will require an operation. So we were identifying a problem that we didn’t think was there before.”
Prof Hughes and his team began to notice other trends too, particularly the increase in ‘hypospadias’, a condition whereby the opening where the urine comes out isn’t at the tip of the penis, but further up; in severe cases as high up as a girl’s “and the poor old boy has to sit down to pee”.
This tied in with an experiment that had been done previously on rats. Scientists were becoming concerned that Bisphenol A (BPA), a chemical found in all sorts of plastics – from food containers to baby bottles – had an oestrogen-like effect, making it an ‘endocrine disruptor’.
“They dumped a pile of BPA into a mother rat, and looked at her offspring, and all her male offspring had undescended testes and hypospadias,” explains Prof Hughes.
“Now there’s been this huge controversy about baby bottles: in Canada and several other countries they have banned plastic bottles because of BPA in the plastic. They haven’t done it in this country because it’s very difficult to prove that these chemicals are causing problems. That’s why we’re doing all this work.”
The effect of herbicides and pesticides are also being analysed: “If you live on a farm, by definition you’re almost certainly going to be exposed to more pesticides. And if you look at people who work on the land versus people who work in an urban area, people who work on the land have children with a higher incidence of undescended testes. So there’s obviously something there,” says Prof Hughes.
Other chemicals that interest – and worry – the team are found in flame-retardants. “Everything at home, by law, has to have flame-retardants in the material. But now it’s been found that these are probably one of the most potent endocrine disruptors.