Mortality risks

Age and sex-specific projected mortality data were obtained from the ABS [19] (Appendix 8). Mortality for the sub-population with obesity were estimated considering the total mortality rate and the increased risk of mortality conferred by obesity. A systematic review and meta-analysis by the Global BMI Mortality Collaboration estimated that the hazard ratio for people with obesity compared to those in the normal BMI range in Australia and New Zealand is 1.44 (95% confidence interval (CI): 1.34 to 1.54) [20]. As the hazard ratio for overweight people was minimal and statistically non-significant (HR 1.01, 95% CI: 0.93 to 1.08) [20], we assumed that the risk of mortality for those who were overweight was the same as those of normal weight. Of note, the mortality hazard ratio for people with obesity remained constant across age and sex groups. The formulae used to calculate the mortality rates for people with obesity and people who were non-obese (normal/overweight) are included in Appendix 9.