The landmark AusDiab study surveyed 11,247 Australian adults aged 25 years or over in 1999 and 2000. In 2004 and 2005, 6537 of these participants returned for a follow-up physical examination.
The study found that men and women who were obese were more than twice as likely to develop diabetes, high blood pressure, abnormal blood lipid (cholesterol) levels and the metabolic syndrome over the next 5 years compared to those with a normal waist circumference.
It also found that the risk for each of these conditions started to increase at what were considered normal levels of waist circumference.
"Our findings confirm that abdominal obesity confers a considerably heightened risk of type 2 diabetes, the metabolic syndrome, and heart disease," said Mr Adrian Cameron, an epidemiologist at the Baker IDI Heart and Diabetes Institute in Melbourne.
"No association between risk of death and obesity was evident; however as has been shown in many other studies, this may become evident only with longer follow-up of this population."
Mr Cameron said that the AusDiab study assessed four of the top five health risks associated with obesity, but did not include several other obesity-related conditions, including osteoarthritis, cancers, chronic obstructive pulmonary disease, gall bladder disease, sleep apnoea and depression.
"Tackling the obesity epidemic will require environmental and policy initiatives that provide realistic and achievable opportunities for Australians to be more active, to avoid too much time spent sitting and to avoid unhealthy foods," he said.
Mr Cameron said the data from the study would be used to make more precise estimates of the total financial and health burden attributable to obesity in Australia. It could also be used to assess the likely impact of obesity prevention measures.
Professor Paul Zimmet, Director Emeritus of the Baker IDI Heart and Diabetes Institute said that these findings again underlined the pivotal role the AusDiab study has played in helping to define the importance and strategies for prevention of heart disease and diabetes in Australia.
The Medical Journal of Australia
is a publication of the Australian Medical Association.