Using the popular Body Mass Index (BMI) and the waist circumference method, Deakin University researcher, Associate Professor Julie Pasco and her research team examined the prevalence of obesity among 1467 men and 1076 women aged 20 to 96 enrolled in the Geelong Osteoporosis Study.
The study is significant because the number of people participating in it and the results from it can be seen to be representative of the nation as a whole.
It found that using the BMI (measures of weight corrected for height) – 45.1% of men and 30.2% of women are overweight and a further 20.2% of men and 28.6% of women are obese.
Using the waist circumference measurement method the study found that 27.5% of men and 23.3% of women are overweight, and 29.3% of men and 44.1% of women are obese.
“It is alarming to realise that regardless of the measuring method used approximately 60% of the population exceeds recommended thresholds for healthy body composition,” Associate Professor Pasco said.
“Our data show that obesity rates have increased by one quarter since the turn of the century.
“This is of grave concern because obesity is associated with increased risk for developing high blood pressure, type 2 diabetes, heart disease, stroke, osteoarthritis and some cancers.”
Associate Professor Pasco said the study also showed that, compared with women, BMI overestimated the amount of body fat in men.
“This is because excess weight can be largely due to muscular body builds and heavier bones in men,” she said.
“We also found a greater prevalence of obesity in women than in men.
“What is also of some concern is that according to BMI it is likely that obesity is underestimated among elderly people.
“This is because when elderly people lose body mass, there is an uneven loss of muscle, fat and bone.”
Associate Professor Pasco said for growing children and adolescents BMI may also be an unreliable indicator of actual body fat.
Associate Professor Pasco urged parents and health professionals to factor in gender, age and ethnicity when testing for obesity.
The Geelong Osteoporosis Study is a population-based health study being conducted by the Barwon Epidemiology and Biostatistics Unit at Barwon Health, a strong partnership between Deakin University’s School of Medicine and Barwon Health. Associate Professor Pasco is the Unit Head and lead investigator of the study.
The Geelong Osteoporosis Study commenced in the early 1990s and involves over 3000 residents from Geelong and surrounding regions who were selected at random from electoral rolls and invited to participate in the study. Participants visit the research centre at Barwon Health every few years to have their health monitored.