A third of Australians have “unmanaged” high blood cholesterol, and one in five adults with diabetes do not know they have the condition, according to the results of a biomedical survey for chronic diseases undertaken by the Australian Bureau of Statistics (ABS). The study also found that obesity increased the risk of both high cholesterol and diabetes.

For the first time, the Australian Health Survey (AHS), conducted by the ABS, incorporated a biomedical collection, the National Health Measures Survey (NHMS). It involved the collection of a range of blood and urine tests from over 11,000 participants across Australia, which were tested for various chronic disease and nutrient biomarkers.

Only one in ten Australians with high cholesterol are aware of it

The results of the NHMS showed that 5.6 million Australian adults have high total cholesterol levels, but that many may not know they had the condition.

“The blood test results showed that one in three Australian adults, or 5.6 million people, had high total cholesterol levels,” said Dr Paul Jelfs, Head of the Social Health and Labour Division at the ABS. “Yet only one in every ten people in this group already knew they had it,” he said.

The ABS said the range of cardiovascular tests in the survey showed that the majority of Australians aged 45 and over were at risk of heart disease.

“The results showed that around three in every four Australians aged 45 and over had risk factors for heart disease,” Dr Jelfs said. “That is, they were either taking cholesterol-lowering medication, or their blood test results showed that they had one or more of high cholesterol, high ‘bad’ cholesterol, low ‘good’ cholesterol or high triglycerides (fats in the blood),” he said.

The ABS said the picture was “not much brighter” for young people, with nearly half of those aged under 45 having at least one of these risk factors.

One case of undiagnosed diabetes for every four diagnosed

The survey also found that around one in five adults with diabetes do not know they have the condition.

“We know from our survey that around four per cent of Australian adults have been told they have diabetes,” Dr Jelfs said. “The voluntary blood test results showed that an extra one per cent had diabetes but were not previously aware of it,” he said.

The ABS said the results also showed that a further three per cent of adults were at high risk of diabetes.

“This means that there were an extra three people at high risk of diabetes for every four people who had been diagnosed,” Dr Jelfs said.

Obesity a major risk factor

Obese people were much more likely than their normal weight counterparts to have signs of cardiovascular disease, according to the survey. They were also seven times more likely to have diabetes than people who were normal weight or underweight.

“The results showed that obese adults were nearly five times more likely than normal weight or underweight adults to have high triglycerides, and more than twice as likely to have lower than normal levels of good cholesterol,” Dr Jelfs said. “These are significant risk factors for cardiovascular disease,” he said.

“Worryingly, many younger obese adults showed signs of cardiovascular disease,” Dr Jelfs said.

The ABS said the results showed that one in every three obese people aged under 45 had high total cholesterol – twice the rate for people aged 18-44 who were of normal weight or underweight.

“Obese people aged 18-44 years were also five times more likely than their normal weight or underweight peers to have high trigylcerides,” Dr Jelfs said.

The survey also showed that obesity was a major risk factor for other chronic health conditions, such as diabetes and liver disease. In 2011-12, obese adults were seven times more likely to have diabetes and four times more likely to have signs of liver disease than normal weight or underweight adults.

Heart Foundations calls for national vascular health check program

The National Heart Foundation of Australia, which contributed to funding for the biomedical testing, has called on the Australian Government to fund a national vascular health check program after the “disturbing” survey results.

“High cholesterol is a major risk factor for heart attack, stroke and peripheral vascular disease and having multiple risk factors places you at higher risk,” said Dr Lyn Roberts, the Heart Foundation’s National CEO.

“In New Zealand, 60 per cent of the eligible population (generally those aged 45 and over) have had a heart and diabetes check in the past five years. They are now moving more towards a target of 90 per cent during 2014,” Dr Roberts said. “Australia is a long way behind our neighbor, with some estimate showing only 5 per cent of Australians are getting a heart health check by their doctor,” she said.

The Heart Foundation said cardiovascular disease, diabetes and chronic kidney disease together accounted for “almost two thirds of all deaths and a quarter of the burden of disease in Australia”.

AusVeg says results should “remind Australians to eat more vegetables”

Australian vegetable and potato growers’ representative body AusVeg said the survey results should encourage all Australians to increase their daily intake of vegetables.

“The fact that a great number of Australians are unknowingly walking around with high cholesterol is concerning, however, it should serve as a reminder that a healthy diet of fresh produce can aid in improving cardiovascular health,” said Michael Bodnarcuk, AusVeg spokesperson.

“A high intake of both fruit and vegetables can reduce the risk of coronary heart disease, the leading cause of death in Australia,” Mr Bodnarcuk said. “Research has also demonstrated that the consumption of fruit and vegetables has been associated with lower concentrations of low-density lipoprotein (LDL) or ‘bad’ cholesterol,” he said.

The 2011-13 Australian Health Survey is the largest and most comprehensive health survey ever conducted in Australia, according to the ABS. The survey, conducted through Australia, collected a range of information about health related issues, including health status, risk factor, health service usage and medications.  In 2011-13, the AHS incorporated the first ABS biomedical collection. The biomedical survey was conducted by the ABS and funded by the Australian Department of Health and Ageing and the National Heart Foundation.

The AHS also included an additional representative sample of Aboriginal and Torres Strait Islander people. Results for the Aboriginal and Torres Strait Islander population will be released progressively from the end of 2013.