High cholesterol: Scottish data

Prevalence

The Scottish Health Survey measures the total and HDL-cholesterol of a sample of participants and collects information on whether the participants are taking lipid lowering medication to treat high cholesterol. A new contract was issued from 2012-2015 and saw the removal of the nurse module in which cholesterol measurements were taken. This means that there is no update for levels of cholesterol. The survey team is currently considering re-instating a periodic nurse visit for a sample of respondents to obtain data in the future.

Mean cholesterol

Mean total cholesterol of participants in the Scottish Health Survey is shown in the "Raised Cholesterol - means" worksheet of the Raised Cholesterol(90Kb) Excel workbook. This information has been split by age group, gender and whether the participant is taking lipid lowering medication. These results suggest that the estimated average total cholesterol level for adults aged 16-64 years in Scotland is slightly above the current UK limit for 'raised cholesterol' (5.0 mmol/l), and high compared to the 'optimum' level of 3.8 mmol/l.

Note: Unlike the 1995, 1998 and 2003 surveys, since 2008 only a sub-sample of adults in the main sample are eligible to take part in the Stage 2 nurse visit. As a consequence, results by age group cannot be broken down by age based on one year's data and results by age group have been combined for 2008 and 2009, 2010 and 2011 and for 2008 to 2011. Even after combining data, the results are still based on a considerably smaller sub-sample of adults than the previous Scottish Health Surveys. Therefore confidence intervals around the figures since 2003 will be larger than for results from previous years.

Raised cholesterol

The current threshold used to determine 'raised' cholesterol in the UK is 5.0 mmol/l. Previously the threshold was 6.5 mmol/l. The "Raised Cholesterol 5.00 cutoff" worksheet of the Raised Cholesterol(90Kb) Excel workbook shows the estimated percentage of the Scottish population above the current UK threshold for 'raised' cholesterol (5.0 mmol/l). The data show that 56% of men and 56% of women (including those taking lipid lowering medication) aged 16-64 years had cholesterol levels above 5.0 mmol/l in 2010/11. Excluding those taking lipid lowering medication prevalence was around 60% for both men and women. In general, the percentage with a raised cholesterol level increases with age (however, see note above). In more recent years there is a suggestion in the data that this pattern is changing, especially for men, possibly as a result of screening and targeted treatment.

There appears to be a general downward trend in the percentage with a raised cholesterol level. However it must be remembered that the results since 2003 are based on a considerably smaller sub-sample of adults than the previous Scottish Health Surveys and there could be effects from random variation or the way the test is carried out.

The "Raised Cholesterol 6.5 cutoff" worksheet of the Raised Cholesterol(90Kb) Excel workbook shows the estimated percentage of the Scottish population above the previous threshold of 6.5 mmol/l. The data show that 13% of men and 16% of women (including those taking lipid lowering medication) aged 16-64 years had cholesterol levels above 6.5 mmol/l in 2010/11. Excluding those taking lipid lowering medication prevalence was around 14% for men and 17% for women. In general, the percentage with a raised cholesterol level increases with age initially and then often decreases in older age bands (however, see note above).

There appears to be a general downward trend in the percentage of men with a raised cholesterol level but a less consistent pattern for women. There could be effects from random variation or the way the test is carried out. It must also be remembered that the results since 2003 are based on a considerably smaller sub-sample of adults than the previous Scottish Health Surveys.

Primary care activity

Data on people consulting with a member of the general practice team because of high cholesterol was available from the Practice Team Information (PTI) data collected by ISD Scotland. Collection of PTI data has now been discontinued, but the Scottish Primary Care Information Resource (SPIRE) - a collaboration between the Scottish Government and NHS National Services Scotland is expected to provide GP consultation data in the future.

Historical data from 2003/4 to 2012/13 are shown in this Excel file(77kb) which includes three worksheets:

• It is estimated that approximately 37,660 people (0.7% of the population registered with a GP) consulted a member of the general practice team (GP or practice-employed nurses combined) at least once during 2012/13 because of a high cholesterol level. This has reduced from an estimated 39,990 (0.7%) in 2011/12 and 64,790 (1.2%) in 2003/4 (revised figures) (worksheet 1)

• Over the period 2003/04 to 2012/13, consistently, fewer males than females consulted a member of the general practice team because of a high cholesterol level: an estimated 18,010 males compared to 19,660 females in 2012/13 (0.66% compared to 0.70% of the registered population) (worksheet 1)

• A greater number of people living in the least deprived than the most deprived areas consulted a member of the general practice team because of a high cholesterol level in 2012/13. This gradient across deprivation quintiles was generally evident throughout the period 2003/04 to 2012/13 for both the number of people consulting and the rate per 1,000 registered, although it was more noticeable for males than females and confidence intervals between the most and the least deprived deprivation categories overlap in some instances (worksheet 2)

• The deprivation gradient is also evident in the annual average number of contacts with a member of the general practice team because of a high cholesterol level. In 2012/13, the average number of annual contacts was 1.4 for males and 1.5 for females. For both males and females, the average number was higher for those living in the least deprived quintiles than those in the most deprived quintiles, although confidence intervals overlap between deprivation categories (worksheet 3).

Note 1: PTI are likely to underestimate the population being treated for high cholesterol either on its own or because of high overall cardiovascular risk because not all individuals will consult their general practice within the year.

Note 2: PTI aims to continually improve the interpretation of the data and therefore analysis methods are regularly reviewed and sometimes updated. Previously, the most recent age-gender-deprivation category was applied retrospectively to all historical data. With new postcodes being introduced, alterations or withdrawal of existing postcodes as well as regular updates of the deprivation calculation and categorisation, this could lead to a reduction in accuracy over time. Deprivation figures are now calculated using the most appropriate SIMD release for that time period. It was therefore necessary to rerun the analysis and update figures for all years. For more details see the Note of Revisions.

Note 3: The final worksheet named 'Reads' lists the Read codes used in the PTI analyses to define high cholesterol. The Read codes that have been used have been revised since previous data presented here, so old versions of this excel file are not comparable to this new data.