The Scottish Government

« Previous | Contents | Next »

Listen

3. KEY STATISTICS ON HEALTH INEQUALITIES - SUMMARY PAPER

SCOTLAND IN CONTEXT

1.1 Inequalities within Scotland

In Scotland today, there is evidence of significant health inequalities in terms of mortality, physical illness, mental health and wellbeing, lifestyle behaviours associated with ill health and access to and use of health services. Deprivation and socio-economic inequalities are of particular policy interest. Inequalities are also evident according to gender, age, education, ethnicity, sexual orientation and the presence of disability or mental health problems. An overview of statistics on health inequalities is provided in a separate background paper: "Statistics on Health Inequalities - An overview". http://www.scotland.gov.uk/Topics/Health/inequalitiestaskforce/overviewofstatistics. In this paper, the term inequalities refers to deprivation inequalities unless otherwise stated.

Most of the statistics available on health inequalities are simple breakdowns by a single determinant, which do not take into account the influence of other factors associated with the health indicator concerned. In reality, there will be complex interactions between factors that contribute to the initiation or exacerbation of particular conditions or the lifestyle choices people make. In addition to this, it is difficult to investigate issues affecting some groups, because of the relatively small numbers of people involved and/or because little information has been collected about them. In particular, this is an issue for ethnic minority groups in Scotland, religious groups, groups defined by their sexual orientation and transgender people.

Life expectancy and healthy life expectancy are often used as indicators of the overall health of the population - and of inequalities between different sections of the population. There is a clear pattern of increasing life expectancy with decreasing deprivation in Scotland. Life expectancy is also consistently higher for Scottish women than men ¹ (Figure 1).

Figure 1 Life expectancy at birth by gender and deprivation Scotland 2003-2005

Source: General Register Office for Scotland GRO(S)

A similar pattern is observed for healthy life expectancy: males in the least deprived fifth of the Scottish population are expected to live 94% of their life in good health - compared with 85% in the most deprived fifth; females in the least deprived fifth are expected to live 93% of their life in good health - compared with 84% in the most deprived fifth of the population. ²

1.2 Scotland compared to the United Kingdom and Europe

In terms of health and mortality, Scotland generally compares unfavourably with the rest of the United Kingdom, the European average, other small countries in Europe and is frequently more on a par with Eastern European countries than with its more affluent neighbours.

This is often because particularly poor performance in the most deprived and disadvantaged areas or population dominate the overall picture for Scotland. However, some European nations have healthier populations than Scotland despite having higher levels of poverty and deprivation. Ongoing research by the Glasgow Centre for Population Health and NHS Health Scotland is comparing Scotland/West of Scotland with similar regions in Europe (in terms of a shared history of industrialisation and subsequent deindustrialisation) and examining trends in health outcomes (e.g. mortality) and health determinants. Initial analyses have shown that despite many comparable European regions having apparently worse socio-economic profiles, their life expectancy appears to be higher and/or increasing at a faster rate than is the case in Scotland/West of Scotland. In-depth analysis of age and cause specific mortality has highlighted a number of key 'drivers' behind these trends including higher death rates from external causes such as suicide and alcohol misuse for working age men and higher rates of cancer and circulatory diseases amongst women aged 45 to 64. The results of this stage of the project will be published by the end of the year. Thereafter, further work will be undertaken to collate a broad range of heath determinant data, and the analysis will be extended to cover regions which - from analysis already undertaken - appear the most similar to Scotland/West of Scotland in terms of their current socio-economic status.

Scotland's relative position in Europe has not always been so bad. Scotland now lags behind because improvements since the beginning of the 20th century have been at a slower rate than for most other European countries ³ (Figure 2).

Figure 2 20th century trends in male life expectancy - Scotland compared to 16 other European countries

Source: Leon D; Government Actuary Department (for 2000 figures)

2 Factors contributing to inequalities in life expectancy and healthy life expectancy

Life expectancy is estimated using mortality rates in the population at a given time. Healthy life expectancy is estimated using a combination of mortality rates and indicators of ill-health or disability (people's assessment of their health and/or the presence of limiting long-term illness).

The most common causes of death do not correlate with the most common causes of ill-health (based on GP contact data and inpatient diagnoses) because most of the reasons people attend a GP or hospital are not immediately life-threatening and can be treated (Tables 1 and 2).

Table 1

Source: Scottish Public Health Observatory; General Register Office for Scotland

Table 2

Source: Information Service Division ( ISD)

In addition, people's own assessment of their health (on which healthy life expectancy is based) will be influenced by their mental health and wellbeing. Poor mental health and wellbeing has also been widely associated with an increased likelihood of poor physical health and decreased survival. Deprivation inequalities in mental health and wellbeing (of which evidence is presented in the statistics overview paper) are likely to contribute to the gaps in both life expectancy and healthy life expectancy.

Leyland et al ⁴ highlighted large relative inequalities in deaths amongst young men and women, most notably relating to deaths from accidents, suicide, disorders due to the use of drugs and assault (Figure 3). These relative inequalities do not however take into account the absolute number of deaths. Some of the biggest inequalities observed are based on relatively small numbers of deaths, which are unlikely to be making a significant contribution to deprivation differences in overall life expectancy. Relative inequalities in deaths from cancer, circulatory disease and respiratory disease may look less dramatic, but the number of deaths involved make up a considerable proportion of total mortality - and therefore are more likely to make a significant contribution to overall life expectancy.

Figure 3 Relative inequalities in mortality by cause, men, Scotland 2001

Leyland's analysis also shows that in recent years mortality rates among young men in disadvantaged areas have been increasing at a time when rates across the rest of the population have been decreasing. If this trend were to continue, it could feed through to even higher rates as this group gets older. For example, drug injecting is much more common among young men and women in disadvantaged areas. Many drug injectors have become infected with hepatitis C and the number who are developing serious and potentially fatal liver disease as a result is steadily increasing.

There is ample evidence of deprivation inequalities in mortality from Scotland's biggest killers (coronary heart disease, cancer and stroke). The largest absolute number of deaths from these conditions occur in the oldest age groups, but this is also where inequalities tend to have narrowed. Reductions in the deprivation gap in life expectancy could however be achieved through reductions in the number of premature deaths from these conditions - and from the other conditions most commonly causing deaths amongst the under 65s (Table 3).

Table 3

Source: Scottish Public Health Observatory

It is also important to consider trends over time, because inequalities in factors lower down the list of common causes of death might become more important in future years. In particular, alcohol related deaths are increasing in Scotland, whilst they are decreasing elsewhere in Europe (Figure 4). If these trends continue, alcohol related deaths could overtake the other main causes of death (for which mortality rates in all deprivation groups are decreasing over time). There are around five times as many alcohol related deaths in the most deprived fifth of areas in Scotland compared with the least deprived fifth of areas.

Another cause of morbidity and mortality which is increasingly becoming a public health priority is chronic obstructive pulmonary disease ( COPD). Although there are currently no statistics available on deprivation inequalities in COPD, marked deprivation inequalities in smoking (which is the major risk factor for developing COPD) suggest that deprivation inequalities in COPD are inevitable.

Figure 4 Alcohol related deaths

Source: Scottish Public Health Observatory

2.1 The role of smoking in health inequalities

It has recently been estimated that smoking accounts for about 24% of all deaths in Scotland, rising to as much as 34% in some areas. ⁵ It has been estimated that lifelong smokers die on average about 10 years younger than non-smokers. ⁶ Smoking also causes a great deal of long-term ill-health due to diseases of the heart, lung and arteries and a long list of cancers and other conditions.

There is a currently a clear relationship between smoking and deprivation. The most recent Scottish Household Survey shows adult smoking rates varying from 12% in the least deprived fifth of the population to 41% in the most disadvantaged. This is a huge change from the situation fifty years ago when around 80% of men and 50% of women were smokers across the whole population. The decline in smoking rates can explain much of the decrease in rates of coronary heart disease and almost all the decrease in rates of lung cancer among men. It can also explain much of the widening health inequality between affluent and deprived areas, because smoking rates have dropped much faster in the former. A large international study, involving the United Kingdom, concluded that between half and two-thirds of the inequalities between high and low income men in Europe are due to smoking. ⁷

A recent 28 year follow-up study of over 15,000 men and women in Renfrew has shown clearly that even the most affluent smokers experience higher mortality rates and die sooner than non-smokers living in the most disadvantaged areas. ⁸ The study also found that the differences in mortality rates between smokers and non-smokers were much larger than those between high and low income groups of the same smoking status (Figure 5). It has also been shown that people who stop smoking can expect to live longer as a result, recovering 9 years if they stop at age 30 down to 3 years at 60. These findings show clearly that there is a huge health inequality between smokers and non-smokers, regardless of socio-economic circumstances.

At the same time, smoking explains at least half the health inequalities related to socio-economic circumstances in Scotland because smoking rates are currently much higher in more disadvantaged areas. For these reasons helping people to stop smoking and discouraging children and young people from starting, regardless of their social circumstances, should remain the top priority for health improvement in Scotland for the foreseeable future. Equally, targeting efforts to help more disadvantaged people stop smoking offers the best opportunity for reducing health inequalities related to socio-economic circumstances in the medium term.

Figure 5 Age-adjusted survival curves over 28 years of follow-up for female never-smokers and current smokers in social class I and II and IV and V in Renfrew and Paisley

Source: Gruer et al

2.2 Other risk factors

Relationships between other lifestyle or risk factors and deprivation are however less clear, for example:

• Binge drinking amongst men appears to increase with increasing deprivation, but weekly consumption of alcohol does not follow the same pattern.

• There is no clear relationship between physical activity and deprivation for adults or children.

• Rates of obesity increase with increasing deprivation for adult women, but not for men or children.

It is likely that this lack of clear evidence of simple relationships with deprivation is due to the complexities of factors determining lifestyle choices and outcomes such as obesity rather than an absence of inequalities.

Just as smoking in itself is a cause of severe health inequalities, so is obesity. Follow up studies are increasingly showing the big increases in risk due to obesity of diabetes, heart disease, breast, bowel, prostate and other cancers, osteoarthritis, dementia and other conditions. Figure 6 shows the huge increase in risk of diabetes that accompanies increasing levels of obesity as measured by body mass index. Thus although the relationship between obesity and socio-economic circumstances is not clear cut, the relationship between obesity, regardless of social circumstances, and health inequality is unarguable. Obesity is a growing cause of ill-health that threatens to cancel out many of the health gains made over the past 20 years.

Figure 6 Body mass index and relative risk for type 2 diabetes among American nurses

Source: Colditz et al 1995

Relationships between unemployment or poverty and poor mental and physical health are also well documented. Not only does poor health prevent people from being economically inactive, there is also evidence that being unemployed or in financial difficulty increases the likelihood of becoming disabled, ⁹ increases stress ¹⁰ and leads to low levels of social inclusion, which is a risk factor for poor mental health and coronary heart disease. ¹¹

2.3 Health inequalities in the early years

There is mounting evidence of markedly widening inequalities between higher and lower income groups in a range of factors that have a profound influence on the future health of children now being born in Scotland. This is observed in both routine statistics and those from various studies, notably Growing Up in Scotland which published its first report in early 2007. This is a prospective study of a representative sample of about 8000 babies and toddlers and their parents, recruited in 2005. ¹² It shows that children born to parents in the lowest income quintile are much more likely than others to have been affected by maternal smoking, drinking or drug use during pregnancy, to have a single, teenage mother, not to have been breast-fed, to be exposed to secondhand tobacco smoke at home, to be weaned onto an unhealthy diet, to have poor dental health, and to receive relatively little stimulation. For many of the estimated 41,000-59,000 children in Scotland with at least one parent who is a problem drug user and at least as many again with one or both parents who are problem drinkers, the prospects may be even bleaker. ¹³ All these adverse interacting factors are creating profound disadvantage for large numbers of children which contrast starkly with the unprecedented prospects for good health experienced by children at the other end of the social spectrum. Success in reducing these inequalities is essential if the health gap is not to become even wider for the next generation.

3 Trends in inequalities over time

Improvements over time in Scottish life expectancy and healthy life expectancy have been observed. However, healthy life expectancy is increasing at a slower rate than life expectancy - meaning that people are living longer, but that more of these years are spent in ill health (Figure 7).

Improvements in life expectancy have been greatest amongst the least deprived population. The deprivation inequality gap in life expectancy therefore appears to be widening over time - and particularly for males (Figure 8). The gender inequality gap is, however, narrowing over time.

Evidence of trends over time in deprivation equalities in healthy life expectancy is not currently available. The Scottish Public Health Observatory is however due to publish a report with updated estimates of healthy life expectancy in autumn 2007, which should address this.

Figure 7 Scotland males: life expectancy ( LE) and healthy life expectancy ( HLE), 1980-2005

Source: Scottish Public Health Observatory

Note that a similar pattern is observed for females, but with life expectancy and healthy life expectancy 5 years and 2 years higher respectively.

Figure 8 Trends in male life expectancy 1991-2001, best and worst constituencies

Assessment of whether there has been a widening or a narrowing in inequalities for individual indicators is hindered by the fact that the majority of routinely published statistics focus on current inequalities and do not show trends over time. A few key examples are however available. A narrowing in deprivation inequalities over time has been observed for:

• Dental health of children (reduction in signs of decay has been greater in the most deprived areas, coinciding with a higher increase in dental access in the most deprived areas).

• Breastfeeding (higher percentage increase in breastfeeding rates at 6-8 weeks in the most deprived areas compared to the least deprived areas).

Meanwhile, a widening over time has been observed for all cause mortality (hence the widening gap in life expectancy). This would suggest that there has been a widening in deprivation inequalities for many causes of death.

Evidence of trends in deprivation inequalities is available from target monitoring information. In 2004, the Scottish Executive set targets "to improve the health and the quality of life of the people of Scotland and to deliver integrated health and community care services making sure there is support and protection for those members of society who are in greatest need". National inequalities targets were set to reduce health inequalities by increasing the rate of improvement across a range of indicators for the most deprived communities by 15% by 2008. The indicators selected were:

• Smoking during pregnancy.

• Adult (aged 16+ years) smoking rates.

• < 75 coronary heart disease mortality.

• Teenage pregnancy (aged 13-15 years).

• Suicide amongst young people (aged 10-24 years).

• < 75 cancer mortality.

The target itself is concerned with improvement in the most deprived areas. For all the indicators, rates are decreasing in the most deprived areas and all but one (teenage pregnancy) are currently on track to meet their 2008 target level.

Improvement in the rest of the population has also been monitored to identify trends in inequalities. The measure of inequality used (ratio of the rate in the most deprived areas to the rate in the most affluent areas) suggests that since the start of the target period, inequalities have widened for four of the six indicators, because the improvement in the most affluent areas has been greater than in the most deprived areas. The two indicators currently showing a narrowing in health inequality during the target period are suicides amongst young people and <75 mortality from coronary heart disease. However, it is important to note that there is fluctuation in the inequality ratio from year to year and often the longer term trend in inequality is not consistent with the trend during the target period. Most notably this is the case for <75 deaths from coronary heart disease, which shows a broadly increasing trend in inequality since the early 1990s (see Figure 7).

Please note also that alternative measures of inequality do not necessarily paint the same picture (see Section 5 of this paper).

4 Should inequalities be tackled using a geographical approach?

4.1 Area based definitions of deprivation

Deprived populations tend to be concentrated in particular geographical areas, hence the use of area based definitions to identify them. However, not all people living in areas defined as deprived are disadvantaged and vice versa. Targeting only areas defined as having the highest concentrations of deprived population will not include deprived people living elsewhere.

In addition to this, most indicators showing deprivation inequalities demonstrate a linear relationship between increasing deprivation and worsening outcomes or health. Targeting only the most deprived therefore fails to address the intermediate groups and so will not improve inequalities observed in the rest of the population.

4.2 The Glasgow effect

Inequalities between the health of people in Glasgow and West Central Scotland compared to the rest of the country are well documented. Glasgow has some of the highest levels of deprivation in Scotland as well as some of the most affluent small areas in the country. The evidence indicates that inequalities between Glasgow and the rest of Scotland are present regardless of deprivation or social class, for example:

• Leyland et al showed that the male mortality rate in each social class was higher in Glasgow than in Clydeside as a whole, and was higher in Clydeside than in the whole of Scotland and concluded that differences in the social structure of the population could not clearly explain the region's higher mortality rate.

• The Glasgow Centre for Population Health has demonstrated that following adjustments for socio-economic circumstances, health in West Central Scotland is significantly worse than elsewhere in Scotland. This was observed for indicators of mortality, physical illness, mental health and lifestyle behaviours associated with health.

Coupled with the fact that the population of this region represents over a quarter of Scotland's total population and that it has some of the highest levels of deprivation, this evidence suggests that putting a particular emphasis on improving the health of people in the Glasgow region should improve the overall population health for Scotland and reduce overall health inequalities. It also suggests that the determinants of health in the Glasgow region may be different to the rest of Scotland, perhaps calling for different approaches than would be used elsewhere.

5 Measurement of inequalities

5.1 Measures of deprivation

Since 2004, the recommended measure of deprivation is the Scottish Index of Multiple Deprivation ( SIMD). Before the development of SIMD, the measure traditionally used in health analysis was the Carstairs Index. The Carstairs Index does not identify the most deprived areas as accurately as SIMD, because it is based on fewer indicators of deprivation and is produced for larger geographic areas. Therefore, deprivation inequalities often appear greater when SIMD is used.

The majority of routinely published statistics are now based on SIMD. However, the inequalities targets developed by the Scottish Executive are based around the Carstairs Index split into five groups, because this was the recommended measure at the time of their development. It is important to be aware that analysis of these indicators using SIMD identifies higher levels in the most deprived areas and larger inequalities between the most and least deprived.

In addition to this, some analyses compare the most deprived fifth (20%) with the least deprived fifth of areas (quintiles), whilst others use the extreme 10% groups (deciles) and others use the most deprived 15% of the population compared to the rest of the population. Comparison of the most extreme groups will usually indicate the biggest inequalities.

It is recommended that where possible future targets use SIMD deciles to define deprivation.

5.2 Inequality measures

Since the development of the 2004 inequalities targets, various studies have investigated alternative methods of analysing and monitoring inequalities over time. The methods investigated include:

• absolute range (absolute difference between rates in the most and least deprived groups).

• relative range (ratio of rate in the most deprived areas to rate in the least deprived areas - currently used for the existing targets).

• slope index of inequality ( SII) and relative index of inequality ( RII) (which are sensitive to the mean health status of the population and can be interpreted as the absolute effect on health of moving from the lowest socioeconomic group through to the highest).

• concentration index (which allows analysis of the extent to which poor health is concentrated amongst those in the most disadvantaged groups).

• population attributable risk ( PAR) (which measures the proportion of disease in the study population that is attributable to exposure to a particular factor and thus could be eliminated if that exposure were eliminated).

These different methods have pros and cons, for example: ratios in themselves do not give information about absolute improvement and will not inform about performance across the intermediate groups of population; the slope index of inequality and relative index of inequality only work well if there is a reasonably linear relationship between deprivation and the health indicator of interest. It is also important to note that measures of inequality will not necessarily work in localised situations where gradients between deprivation groups defined at a national level might not apply.

A recent review of approaches to measuring socio-economic inequalities in health (by the Scottish Public Health Observatory) recommended that measures are selected on a case by case basis and concluded that using a combination of approaches is often the best way to ensure that inequalities are fully understood.

It is recommended that a combination of measures is used to measure inequalities associated with targets.

5.3 Measuring the costs of health inequalities

A reduction in health inequalities, by improving the health of those most deprived, is likely to result in a reduction of costs to the NHS and society as a whole. Such cost savings are difficult to estimate, because of the methods involved and also because of the wide range of inequalities that exist. However, despite these difficulties, this type of analysis has been attempted for several health issues and these suggest that there are significant costs associated with preventable illnesses, particularly when wider economic and social costs are set alongside costs to the NHS. For example, in 2002-03 alcohol is estimated to have cost NHSScotland £110.5m and the wider economic, human and social costs amounted to some £736m. ¹⁴ Of the topics on which costs have been calculated for Scotland (alcohol, smoking, obesity, mental illness, teenage pregnancy, asthma), mental illness is estimated to incur the highest costs - £1574m to the NHS and £7,071m in wider economic and social costs. ¹⁵ A similar analysis for England also ranked mental illness as having the largest societal cost. There are a number of important caveats regarding the presentation of information on the cost of inequalities and these are discussed more fully in the background paper: "Statistics on health inequalities - an overview".

October 2007

« Previous | Contents | Next »