Prevalence+and+Population+Information

Prevalence - how does Australia rate?
Unfortunately, there is no universal definition of hyperlipidaemia - even a definition for elevated total blood cholesterol (TC) is lacking. In Australian statistics a high TC is most commonly regarded as ≥ 5.5mmol/L (~210mg/dL). In the United States, TC of < 200mg/dL is Desirable and ≥ 240mg/dL is High Risk. European statistics commonly target TC at 190mg/dL (or 5.0mmol/L) and the Canadians have abandoned TC as a target (preferring to target arthrogenic LDL-C and the TC:HDL-C ratios).

Even consistent definitions of age class categorisations are elusive. In the USA, adults are ≥ 20 years of age, whereas in Australia published data for the adult population is based on sampling of persons aged 25 and over. Another confounding factor in prevalence statistics, is study methodology. Some studies rely on blood analysis of a population sample, whereas many other rely on self reporting using survey instruments. So direct comparison between reported data for different countries is fraught with danger, but within country time-series data is informative.

The 1999-2000 Australian Diabetes, Obesity and Lifestyle Study estimated that **almost 50% of Australians aged 25 and over had high total blood cholesterol** - defined as in excess of 5.5 mmol/L (~210mg/dL). This Study involved blood samples and other biomedical assessments of 11247 people aged 25 and over. The AusDiab survey result suggested that almost 6.5 million adult Australians had high total blood cholesterol.

More recent Australian data from the Australian Bureau of Statistics' National Health Survey 2004-05 paints a healthier picture, but the ABS data depends on self reporting, a less reliable estimator that direct blood sampling as undertaken in the AusDiab study. This data suggests that only 1.3 million Australians have high blood cholesterol, **just 7% of the entire Australian population**. Note the conflict with the PBS data below. which suggests that at least 2 million Australians filled prescriptions for lipid lowering medications in 2007-08.

Data from the Untied States, based on self reporting, suggests that in 2008, 44.4% of adults aged 20 and over had TC > 200mg/dL and 15% had total cholesterol >240mg/dL.

**Which age groups are most at risk?**
The AIHW analysis of the AusDiab data found that the prevalence of high blood cholesterol increased with age to a peak for females aged 65–74 years; and for males aged 55–64 years. In the younger age groups there was a greater proportion of males with high blood cholesterol than females; however, at 55 years of age females overtook males.



Is the Cholesterol problem getting better or worse?
AIHW (2010) reports that average blood cholesterol levels of Australian adults in 1999–2000 were very similar to those 20 years earlier. Consistent with the trends in average levels, there was no apparent reduction in the prevalence of people with high blood cholesterol over that period. Whereas in the United States, the situation appears to be improving. In the United States, the age-adjusted mean total serum cholesterol level of adults 20 years of age decreased from 206 to 203 mg/dL, and LDL cholesterol levels decreased from 129 to 123 mg/dL between the periods 1988–1994 and 1999–2002. Further reduction in the average serum total crude mean cholesterol level in adults 20 years of age occurred in the period 2003–2006 (NCHS), with 198 mg/dL for men and 202 mg/dL for women.

The Economic Impact of High Blood Cholesterol
According to analysis by the Australian Institute of Health and Welfare, high blood cholesterol was estimated to have caused about 6% of the total burden of disease among Australians in 2003, with coronary heart disease and stroke accounting for the whole of cholesterol’s burden. About 80% of the burden was related to premature deaths and 20% to disability.

Medication Statistics
Analysis of Pharmaceutical Benefit Scheme (PBS) data by the AIHW (2010) shows that, during the 2007–08 financial year, just over 2 million people in Australia filled prescriptions for medicines with a blood cholesterol lowering effect. However, the authors caution that this data probably underestimates actual total pharmacotherapy levels as it only includes those medications supplied through the PBS.

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