Mortality attributable to higher-than-optimal body mass index in New Zealand

Abstract

Objectives: To estimate the burden of mortality in New Zealand due to higher-than-optimal body mass index (BMI) in 1997, as well as mortality that could be avoided in 2011 with feasible changes in mean population BMI.

Setting: New Zealand.

Design: Comparative risk assessment methodology was used to estimate the attributable and avoidable mortality due to high BMI. Outcomes assessed were ischaemic heart disease (IHD), ischaemic stroke, type 2 diabetes mellitus, colorectal cancer and postmenopausal breast cancer.

Results: In 1997, 3154 deaths (11% of all deaths) in New Zealand were due to higher-than-optimal BMI (>21 kg m(-2)). This amounted to 83% of diabetes deaths, 24% of IHD deaths, 15% of ischaemic stroke deaths and 4% of all cancer deaths. If the projected increase in mean population BMI by 2011 was limited to 1.0 kg m(-2) rather than 1.3 kg m(-2), approximately 385 deaths could be prevented annually, mainly from diabetes.

Conclusions: These results quantify the importance of higher-than-optimal BMI as a major modifiable cause of premature death in New Zealand. Intervention policies that would have only modest effects on slowing the rate of increase in mean population BMI by 2011 could still prevent hundreds of deaths annually.