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In this part we propose population indicators of major chronic disease risk factors. We
will consider risk factors which can be measured through risk factor examination in
population surveys. We also propose some indicators that are related to prevention or
treatments of chronic diseases.
Our proposal is closely related to the proposal for a comprehensive list of health
indicators that has already been prepared by European Community Health Indicators (ECHI),
another project of the Health Monitoring Programme. For the indicators of chronic disease
risk factors, the ECHI project asked the EHRM Project for advice. Therefore, most of the
primary indicators proposed here have already been included in the ECHI proposal. Because
the ECHI project ended a year earlier than EHRM, the EHRM proposal in its final form was
not available to ECHI. The ECHI Project stressed that flexibility is an important
characteristic of their proposal as the interest in specific indicators may change with
changing policy interests and scientific developments.
The indicators proposed by the ECHI Project are defined at the general level, i.e.,
their actual operational definitions have not yet been attempted. The EHRM project gives
operational definitions for its indicators, and also makes detailed recommendations for
procedures that impact on data reliability and comparability in multinational surveys.
The proposed indicators have been classified into two categories, primary and
secondary.
Primary indicators are those that should be available from every risk
factor survey. They can be characterized as being:
- predictive for one or more major chronic diseases,
- modifiable,
- measurable in populations, and
- relevant to the age range considered.
These primary indicators are also proposed for the ECHI list.
Secondary indicators should be considered as optional for risk factor
surveys. They are considered useful but, compared with the primary indicators, their:
- measurement or standardization may be more difficult than for the primary indicators, or
- impact on risk may be less well understood, and/or
- modifiability may be uncertain.
Data for secondary indicators should be collected in future risk factor surveys
whenever feasible.
Standardized procedures for collecting data for the indicators in population surveys as
well as the rules for deriving the indicators from the data are described in Part 3.
Primary indicators
- Mean and standard deviation of systolic blood pressure (mmHg)
- These are calculated from the mean of the second and third of three serial measurements.
- In some surveys in the past, only two measurements have been taken. Therefore, during a
transition period, the first and second measurements may be used.
- Mean and standard deviation of diastolic blood pressure (mmHg)
- These are calculated from the mean of the second and third of three serial measurements.
- In some surveys in the past, only two measurements have been taken. Therefore, during a
transition period, the first and second measurements may be used.
- Prevalence of actual and potential hypertensives
- Numerator: number of those whose systolic blood pressure was at least 140 mmHg or
diastolic blood pressure was at least 90 mmHg or who reported that they are taking
medication to lower their blood pressure.
- Denominator: number of all survey respondents.
- The recommended question for determining the treatment is: "Are you currently
taking medication prescribed by a medical doctor to lower your blood pressure?" In
the past, different variants of the question have been used, but it is unlikely that they
change the result in a major way. Therefore, this simple question is recommended.
- This indicator is a proxy for the primary item of interest, namely the prevalence of
hypertension, whether diagnosed or undiagnosed. Undiagnosed hypertension can not be
identified on the basis of survey blood pressure measurements alone, because established
hypertension requires a sustained elevation of blood pressure which is usually ascertained
by several measurements at different occasions. We define the group of potential
hypertensives as persons with survey blood pressure above the value used in the current
definition of hypertension by the World Health Organization and the International Society
of Hypertension (1). Typically, around 80% of these potential hypertensives would become
diagnosed as hypertensives, if further investigated (2). Thus, our indicator that combines
the actual diagnosed hypertensives and the potential hypertensives will overestimate the
prevalence of hypertension but it represents a practical compromise and yields a
reasonable estimate of the prevalence of hypertension in the population.
- Prevalence of antihypertensive drug treatment among actual and potential
hypertensives
- Numerator: number of those who reported that they are taking medication to lower their
blood pressure.
- Denominator: number of those who were identified as actual or potential hypertensives as
defined above.
- This indicator is crucial for the assessment of the health care system.
- Note that the ideal target for this indicator is not 100% because medication is not the
only treatment for hypertension and the denominator does not only include truly
hypertensive persons.
- Prevalence of antihypertensive drug treatment in the population
- Numerator: number of those who reported that they are taking medication to lower their
blood pressure.
- Denominator: number of all survey respondents.
- The purpose of this indicator is to monitor the antihypertensive treatment in the
population.
- Awareness of elevated blood pressure
- Numerator: number of those who reported that in the past 12 months they have been told
by a health professional to have elevated blood pressure or hypertension.
- Denominator: number of those who were identified as actual or potential hypertensives as
defined above.
- This is crucial for the assessment of the health care system.
- Proportion of the population with blood pressure measurement in the past 5 years
- Numerator: number of those who reported that their blood pressure was measured by
a health professional in the past 5 years.
- Denominator: number of all survey respondents.
Secondary indicators
- Prevalence of elevated systolic blood pressure
- Systolic hypertension is defined as systolic blood pressure 140 mmHg or more.
- Systolic blood pressure, regardless of the level of diastolic blood pressure, has been
recognized as an important predictor of vascular events, particularly in the elderly. (3)
- Distribution curve of systolic blood pressure
- Distribution curve of diastolic blood pressure
- Effectiveness of antihypertensive drug treatment
- Numerator: size of the subset of the denominator whose systolic blood pressure is below
140 mmHg and diastolic below 90 mmHg.
- Denominator: number of those who are taking medication to lower their blood pressure.
- Prevalence of non-pharmacological treatment of hypertension among actual and potential
hypertensives
- Numerator: number of those who reported that they have been ordered by a doctor to
change their way of life in order to lower their blood pressure.
- Denominator: number of those who were identified as actual or potential hypertensives as
defined above.
- Proportion of the population with blood pressure measurement in the past 12 months
- Numerator: number of those who reported that their blood pressure was measured by
a health professional in the past 12 months.
- Denominator: number of all survey respondents.
- Mean and standard deviation of pulse rate (beats/min).
- Pulse rate is commonly determined in connection with blood pressure measurement and its
inclusion as a secondary indicator is based on epidemiological studies that have shown
that heart rate is a predictor for cardiovascular disease independent of associated risk
factors (4-6). A possible link between resting heart rate and cardiovascular events is
physical fitness (7), i.e. the ability to perform aerobic activities, which is
inversely proportional to resting heart rate.
Primary indicators
- Mean and standard deviation of serum total cholesterol (mmol/l)
- Prevalence of elevated serum total cholesterol
- Elevated serum total cholesterol: concentration is 5.0 mmol/l or higher. The cut-point
is based on a recent recommendation of a task force of the European Society of Cardiology,
European Atherosclerosis Society, European Society of Hypertension, International Society
of Behavioral Medicine, European Society of General Practice/Family Medicine and the
European Heart Network (8). Note that the definition does not depend on the person's
treatment status.
- Prevalence of lipid lowering drug treatment in the population
- Numerator: number of those who reported that they are taking medication to lower their
cholesterol.
- Denominator: number of all survey respondents.
- Prevalence of drug treatment among those who have elevated cholesterol was also
considered as a potential indicator. However, the data required for defining the
proportion of the population that should be treated goes beyond the scope of this
recommendation. In the recommendations for initiating lipid lowering drug treatment, the
cut-points for cholesterol depend on the other risk factors, and in particular on whether
the person already has coronary heart disease.
- Awareness of elevated serum cholesterol or hypercholesterolemia
- Numerator: number of those who reported that they have been told by a health
professional in the past 12 months that they have elevated cholesterol or
hypercholesterolemia.
- Denominator: number of those who were considered having elevated cholesterol in item
"prevalence of elevated serum total cholesterol".
- The indicator is relevant for the assessment of the health care system.
- Proportion of the population with cholesterol measurement in the
past 5 years
- Numerator: number of those who reported that their cholesterol was measured by a
health professional in the past 5 years.
- Denominator: number of all survey respondents.
Secondary indicators
- Distribution curves of serum total cholesterol.
- Prevalence of elevated serum total cholesterol using different cut-points:
- 6.0 mmol/l or more
- 7.0 mmol/l or more
- 8.0 mmol/l or more
- Mean and standard deviation of serum HDL cholesterol (mmol/l)
- Prevalence of low HDL cholesterol
- Low HDL cholesterol: concentration is lower than 1.0 mmol/l. The cut-point is based
on a recent recommendation for men by a task force of the European Society of Cardiology,
European Atherosclerosis Society, European Society of Hypertension, International Society
of Behavioral Medicine, European Society of General Practice/Family Medicine and the
European Heart Network (8).
- Mean and standard deviation of serum triglycerides (mmol/l)
- Prevalence of elevated triglycerides
- Elevated triglycerides: concentration is higher than or equal to 2.0 mmol/l. The
cut-point is based on a recommendation in reference (8).
- Mean and standard deviation of serum LDL cholesterol (mmol/l)
- LDL cholesterol is estimated from total cholesterol (TC), HDL cholesterol (HDL) and
triglycerides (TG) using the Friedewald formula: LDL cholesterol = total cholesterol - HDL
cholesterol - 0.45×triglycerides. The formula, however, has the problem that it is valid
only when triglyceride is less than 2.25-4.5 mmol/l, depending on the required accuracy.
Methods for direct measurement of LDL cholesterol have become available recently, and they
may become a better alternative to the estimation by the Friedewald formula.
- Prevalence of elevated LDL cholesterol
- Elevated LDL cholesterol: concentration is higher than or equal to 3.0 mmol/l. The
cut-point is based on a recommendation in reference (8).
- Mean and standard deviation of total cholesterol/HDL cholesterol ratio
- Prevalence of high total cholesterol to HDL cholesterol ratio
- High total cholesterol to HDL cholesterol ratio: ratio is greater than 5 (see reference
(8)).
- Proportion of the population with cholesterol measurement in the past 12 months
- Numerator: number of those who reported that their cholesterol was measured by a
health professional in the past 12 months.
- Denominator: number of all survey respondents
- Prevalence of non-pharmacological treatment of hypercholesterolemia
- Numerator: number of those who reported that they have been order by a doctor to change
their way of life in order to lower their total blood cholesterol.
- Denominator: number of those who were considered having elevated cholesterol in item
"prevalence of elevated serum total cholesterol".
Primary indicators
- Mean and standard deviation of BMI
- These are based on measured weight and height
- Prevalence of obesity:
- Prevalence of BMI > 30. The cut-point is based on a recent recommendation of a
WHO Expert Committee (9).
- Mean and standard deviation of waist circumference
Secondary indicators
- Distribution curve of BMI.
- Distribution curve of weight.
- Distribution curve of height.
- Distribution curve of waist circumference.
- Distribution curve of hip circumference.
- Distribution curve of waist/hip ratio.
- Prevalence of categories of BMI (9):
| Category of BMI |
BMI |
| thin |
< 18.5 |
| normal range |
18.5-25 |
| grade 1 overweight |
25-30 |
| grade 2 overweight |
30-40 |
| grade 3 overweight |
> 40 |
- Mean and standard deviation of waist/hip ratio
- Prevalence of waist/hip ratio > 0.95 for men and > 0.80 for women
- The cut-points come from a consensus from several studies (8,10).
- Mean and standard deviation of height
- Mean and standard deviation of weight
Primary indicators
- Prevalence of daily smokers (11)
- Prevalence of never daily smokers (11)
- Prevalence of ex-daily smokers (11)
- These three prevalence values include all forms of tobacco smoking, such as cigarettes,
cigars and pipe.
- Note that the three prevalence values above are mutually exclusive and sum up to 100%.
- Prevalence of daily cigarette smokers
- This indicator will facilitate the assessment of trend from past surveys, when emphasis
was often placed on cigarette smoking.
Secondary indicators
- Prevalence of occasional smokers (11)
- Mean number of times smoked per day in population
- Mean number of times smoked per day by daily smokers
- Proportion of daily smokers advised by health professionals to quit smoking
- Numerator: the number of daily smokers who, during the past 12 months, have been advised
by a health professional to stop smoking.
- Denominator: number of daily smokers.
- Prevalence of those who are exposed to indoor tobacco smoke at work site.
- Denominator: current non-smokers (= never daily + ex-daily smokers - occasional
smokers).
- Prevalence of those who are exposed to indoor tobacco smoke at home.
- Denominator: current non-smokers (= never daily + ex-daily smokers - occasional
smokers).
Secondary indicators
- Prevalence of use of acetylsalicylic acid or similar drugs to prevent or treat
heart disease or stroke.
- In age group 55-74.
- Numerator: the number of respondents reporting to use of acetylsalicylic acid or similar
drugs to prevent or treat heart disease or stroke.
- Denominator: all survey respondents.
Secondary indicators
- Prevalence of women using HRT.
- In age group 45-74.
- Numerator: the number of female respondents reporting to use HRT.
- Denominator: all female survey respondents.
These indicators might be modified by the ongoing project of the Health Monitoring
Programme on Establishment of Indicators Monitoring Diabetes Mellitus and its Morbidity.
Primary indicators
- Mean and standard deviation of glycated haemoglobin concentration (HbA1c)
Secondary indicators
- Mean and standard deviation of fasting plasma glucose concentration
- Prevalence of impaired fasting glycemia
- Numerator: number of those whose fasting plasma glucose concentration was at least 6.1
mmol/l but less than 7.0 mmol/l.
- Denominator: number of all survey respondents.
- Prevalence of provisional diagnosis of diabetes
- Numerator: number of those whose fasting plasma glucose concentration was 7.0 mmol/l or
more.
- Denominator: number of all survey respondents.
There may be other indicators that are of interest to specific countries. Other
potential indicators, such as homocysteine and fibrinogen, were considered. Because of
complexities or high cost of measurement, or difficulties in standardization, they were
not included in the short list of primary and secondary indicators.
The population subgroups by which the indicators are reported will need to be
standardized.
The indicators should be reported separately for men and women, because the levels and
their trends may differ between the sexes. This is important for several risk factors,
particularly for smoking and obesity, where the patterns for men and women in the same
population may be completely different.
The recommended core age group for monitoring of the risk factors among adults is 35-74
years. Within this age group, the indicators should be reported by ten year age group and
age standardized for the whole age group. The age group 25-34 is relevant and its
inclusion is highly recommended. The same risk factors are also relevant for children and
adolescents, but the survey arrangements and normal values are different. For people
beyond age 75 the role of the conventional risk factors is not well known.
For general public health purposes, the indicators should be representative for a
geographically defined area. While nationally representative data should be the goal, it
is often not feasible to provide data for an entire country. Even if it is possible, it
may be important to report the indicators separately for regions, in order to identify
possible geographical differences and to serve regional decision making. In the selection
of such areas it is important to consider possible comparison with earlier surveys for
assessment of trends.
Remarkable socio-economic differences in the incidence of chronic diseases have been
reported in many countries. Therefore, it will be also important to monitor the risk
factors by socio-economic status. Due to difficulties in the international standardization
of socio-economic categories, only broad categories are suggested:
- Education
- three levels of education attainment (12)
- Living arrangement
- living alone vs. not living alone (13-15)
- Employment status
- working vs. unemployed (16)
- Income:
- Quartiles of the national distribution of personal income (12).
References
- Guidelines subcommittee. 1999 World Health Organization - International Society of
Hypertension guidelines for the management of hypertension. J Hypertens, 1999; 17:
151-183
- Birkett NJ. The effect of alternative criteria for hypertension on estimates of
prevalence and control. J Hypertens 1997;15(3):237-44.
- The sixth report of the Joint National Committee on prevention, detection, evaluation,
and treatment of high blood pressure. Arch Intern Med 1997;157(21):2413-46.3.
- Kannel WB, Kannel C, Paffenbarger RS, Jr., Cupples LA. Heart rate and cardiovascular
mortality: the Framingham Study. Am Heart J 1987;113(6):1489-94.
- Gillum RF, Makuc DM, Feldman JJ. Pulse rate, coronary heart disease, and death:
the NHANES I Epidemiologic Follow-up Study. Am Heart J 1991;121(1 Pt 1):172-7.
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as a predictor of mortality: the MATISS project. Am J Public Health 2001;91(8):1258-63.
- Kannel WB, Wilson P, Blair SN. Epidemiological assessment of the role of physical
activity and fitness in development of cardiovascular disease. Am Heart J
1985;109(4):876-85.
- Prevention of coronary heart disease in clinical practice. Recommendations of the Second
Joint Task Force of European and other Societies on coronary prevention. Eur Heart J,
1998 Oct; 19(10): 1434-503. Available from: URL:http://www.escardio.org/scinfo/Guidelines/98prevention.pdf
- WHO Expert Committee on Physical Status: The Use and Interpretation of Anthropometry.
1998. WHO Technical Report Series, No. 854.
- Lean MEJ, Han CE, Morrison CE. Waist circumference as a measure for indicating need for
weight management. BMJ, 1995; 311: 158-61.
- World Health Organization. Guidelines for controlling and monitoring the tobacco
epidemic. Geneva: WHO; 1998.
- The categorized question on education and income were recommended by the EU Health
Monitoring project "Socio-economic Inequalities in Health".
- Ebrahim S, Wannamethee G, McCallum A, Walker M, Shaper AG. Marital status, change in
marital status, and mortality in middle-aged British men. Am J Epidemiol
1995;142(8):834-42.
- Ben-Shlomo Y, Smith GD, Shipley M, Marmot MG. Magnitude and causes of mortality
differences between married and unmarried men. J Epidemiol Community Health
1993;47(3):200-5.
- Mendes de Leon CF, Appels AW, Otten FW, Schouten EG. Risk of mortality and coronary
heart disease by marital status in middle-aged men in The Netherlands. Int J Epidemiol
1992;21(3):460-6.
- Weber A, Lehnert G. Unemployment and cardiovascular diseases: a causal relationship? Int
Arch Occup Environ Health 1997;70(3):153-60
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