Obesity & Cancer
According to World Health Organisation definitions:
Underweight below 18.5
Healthy weight 18.5 – 25.0
Overweight 25.1 – 29.9
Obese above 30.0
BMI is a reliable indicator of total body fat, which is related to the risk of disease and death. The score is valid for both men and women but it does have some limits. The limits are:
It may overestimate body fat in athletes and others who have a muscular build.
It may underestimate body fat in older persons and others who have lost muscle mass.
Three percent of cancer deaths in Australia are attributable to BMI>25. More recent figures in Europe attribute 5% of cancers to being overweight. A large cohort study in the USA estimated that 14% of all deaths from cancer in men and 20% of those in women could be attributed to overweight and obesity.
Population trends in Australia Adults
The prevalence of obesity in Australia has more than doubled in the past 20 years. Sixty four percent of men and 47% of women either were overweight or obese.
The 1995 National Nutrition Survey found that the proportion of overweight and/or obesity increases with age for both males and females. Among 19-24 year olds, 1 in 3 males and 1 in 4 females are overweight or obese. Among 45 to 64 year olds, this rises to 3 out of 4 males and almost 2 out of 3 females.
The AusDiab Survey in 1999-2000 found that the prevalence of overweight and obesity was almost 60% among Australian adults aged 25 and over.
Survey data for NSW and Victoria indicate that in 1997, over 1 in 5 children were overweight or obese.
A recent study looking at weight changes among Australian children over three decades found that between 1985-1997, the prevalence of overweight and obesity combined doubled, and that of obesity trebled among young Australians, but the increase over the previous 16 years was far smaller. These findings suggest that the prevalence of overweight and obesity among Australian children has increased rapidly over recent years.