Van Gool & Bridges
remains a controversial area of discussion10. Austin (1989) found a relatively high level
of triglycerides in myocardial infarction survivors, however, this relationship is far from
showing a causation between triglycerides and CHD.
A number of papers have identified triglycerides as a risk factor for CHD (Bottinger et
al, 1980 & Bengtsson et al, 1993), however, these have failed to include HDL as an
explanatory variable. Triglycerides are highly positively correlated with other risk
factors, including LDL cholesterol and obesity, while negatively correlated with HDL
(Neil, 1996). Thus its exclusion in a statistical analysis would lead to a multi-
collinearity problem, whilst its inclusion as a risk factor may lead to double counting.
High triglyceride levels at an individual clinical level may be a cause for concern.
Triglyceride measurement on an individual basis is essential in detecting lipoprotein
abnormalities, and identifying treatments. However, at a public health level they have
yet to be identified as an independent risk factor across the community11. Hence,
triglyceride level was excluded as a risk factor in this analysis.
Obesity
The SWSAHS Health Improvement Plan for CHD names obesity as a risk factor in
CHD. Obesityisanobvioustargetfornutritionalstrategies. Yet, finding an
appropriate and consistent measurement of obesity is difficult12.
The Health Improvement Plan measures obesity through the body mass index (BMI).
Overweight is defined as a BMI in the range of 25 to 29.9 kg∕m2, and obesity is defined
as a BMI of 30 kg∕m2 and over.
There is evidence to link obesity to increases in CHD. The Framingham Study, for
example, showed that respondents under the age of 50 years who weighed at least 30%
above desirable body weights (BMI = 28) were at significantly greater risk of CHD
(Hubert et al, 1983). Imeson et al (1989) also found men in the Northwick Park Heart
10 See www.heartfoundation.com.au/docs/pp7.htm as at 24/02/98
" Castelli (1986) found that triglycerides were a significant risk for women over 50 years.
12 See www.heartfoundation.com.au/docs/ppl 1 .htm as at 24/02/98.
57
Chere Project Report 11- November 1999