By Luke Andrews

Toxic chemicals in fragrances, nail polishes, and shampoo may raise the risk of type 2 diabetes in women, a study suggests.

Phthalates are chemicals that strengthen plastic and are used as a lubricant in many cosmetic products. The chemicals can seep through the skin and cause damage to the liver, kidney, lungs and other organs.

Researchers from the University of Michigan who tracked 1,300 middle-aged women over six years found that those with high exposure to the chemicals were 63 percent more likely to develop type 2 diabetes.

The Food and Drug Administration warns these chemicals are also found in hair spray, aftershave, and other beauty products.

Scientists are now attempting to plug the research gap with recent findings saying the chemicals raise the risk of womb tumors, cancer and stunt the growth of newborns.

Phthalate are often added to products during the manufacturing process to give them a particular quality, such as better lubrication or durability.

In the study, published today, scientists recruited 1,300 American women who did not have diabetes.

They used data from the SWAN Multipollutant Study, a survey of middle-aged women. They were monitored for six years — from 2000 to 2006 — with urine samples taken when the study began and in 2002/2003 to test for phthalates.

The scientists assessed the presence of 11 types of phthalates, including low-molecular-weight types commonly used in personal care products such as fragrances, nail polishes, and some feminine hygiene products.

They also looked at Di-2-ethylhexyl metabolites, often found in plastic food packaging and some children's toys.

Over the study period, 61 women developed type 2 diabetes, the scientists found (nearly five percent).

Analysis adjusting for factors including demographics, lifestyle, and health-related factors showed women with high exposure to phthalates were more likely to develop the condition.

Scientists suggest the toxic chemicals may cause diabetes because they can disrupt the hormones insulin and glucagon, which regulate blood sugar and trigger insulin resistance in cells.

Insulin works by causing cells to take up sugar from the blood lowering blood sugar levels, while glucagon has the reverse effect — causing the liver to start releasing sugar when blood sugar levels get too low.

If the body becomes resistant to either of these hormones, it cannot regulate blood sugar levels — triggering type 2 diabetes.

This leaves patients needing to constantly monitor their blood sugar levels and inject themselves with insulin to keep it under control.

In the most serious cases, the condition can lead to patients suffering nerve damage and kidney problems.

Diabetes patients are also at risk of amputation. Narrowed arteries can lead to reduced blood flow to the extremities — such as the feet.

This may lead to wounds being slow to heal, or not healing at all. Should an infection then develop and spread to the bone, doctors may have no option but to amputate.

Type 2 diabetes is linked to lifestyle factors, such as obesity, a poor diet and not getting regular exercise.

Type 1 diabetes, on the other hand, is genetic and normally shows up early in life.

Scientists found that black women were not as affected by phthalates as those of other races. They believe it may have something to do with the different types of cosmetic products used by different races.

Dr Sung Kyun Park, a Michigan epidemiologist who led the study, said: 'Our research found phthalates may contribute to a higher incidence of diabetes in women, especially White women, over a six-year period.

'People are exposed to phthalates daily, increasing their risk of several metabolic diseases. It’s important that we address EDCs now as they are harmful to human health.'

They added: 'Our research is a step in the right direction towards better understanding phthalates’ effect on metabolic diseases, but further investigation is needed.'

Limitations of the research include the fact it had a small sample size and could not prove that phthalates had caused more type 2 diabetes cases.

Other factors such as obesity, a poor diet, and sleep deprivation, could also be at play.