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Age Standardization of Rates: A New WHO Standard

Omar B. Ahmad
Cynthia Boschi-Pinto
Alan D. Lopez
Christopher JL Murray
Rafael Lozano
Mie Inoue
GPE Discussion Paper Series: No.31
World Health Organization 2001
A recent WHO analysis has revealed the need for a new world standard population (see
attached table). This has become particularly pertinent given the rapid and continued
declines in age-specific mortality rates among the oldest old, and the increasing
availability of epidemiological data for higher age groups. There is clearly no conceptual
justification for choosing one standard over another, hence the choice is arbitrary.
However, choosing a standard population with higher proportions in the younger age
groups tends to weight events at these ages disproportionately. Similarly, choosing an
older standard does the opposite. Hence, rather than selecting a standard to match the
current age-structure of some population(s), the WHO adopted a standard based on the
average age-structure of those populations to be compared (the world) over the likely
period of time that a new standard will be used (some 25-30 years), using the latest UN
assessment for 1998 (UN Population Division, 1998). From these estimates, an average
world population age-structure was constructed for the period 2000-2025. The use of an
average world population, as well as a time series of observations, removes the effects of
historical events such as wars and famine on population age composition. The terminal
age group in the new WHO standard population has been extended out to 100 years and
over, rather than the 85 and over as is the current practice. The WHO World Standard
population has fewer children and notably more adults aged 70 and above than the world
standard. It is also notably younger than the European standard.
It is important to note, however, that the age standardized death rates based on the new
standard are not comparable to previous estimates that are based on some earlier
standard(s). However, to facilitate comparative analyses, WHO will disseminate trend
analyses of the completehistorical mortality data using on the new WHO World
Standard Population in future editions of the World Health Statistics Annual.
In epidemiology and demography, most rates, such as incidence, prevalence, mortality,
are strongly age-dependent, with risks rising (e.g. chronic diseases) or declining (e.g.
measles) with age. In part this is biological (e.g. immunity acquisition), and in part it
reflects the hazards of cumulative exposure, as is the case for many forms of cancer. For
many purposes, age-specific comparisons may be the most useful. However,
comparisons of crude age-specific rates over time and between populations may be very
misleading if the underlying age composition differs in the populations being compared.
Hence, for a variety of purposes, a single age-independent index, representing a set of
age-specific rates, may be more appropriate. This is achieved by a process of age
standardization or age adjustment.
There are several techniques for adjusting age-specific rates. Among them are direct and
indirect standardization (Wolfenden, 1923), the geometric mean (Schoen, 1970),
equivalent average death rates (Hill, 1977), life table rates, Yerushalmys index
(Yerushalmy, 1951), cumulative death rates (Breslow and Day, 1981), absolute
probabilities of death and the comparative mortality index ((Peto et al, 1994, Breslow &
Day, 1980, 1981; 1987; Esteve et al, 1994). However, with the increasing availability of
age-specific rates, the use of direct age standardization has become the predominant
technique in most applications of demography and epidemiology.
Direct standardization yields a standardized or age-adjusted death rate, which is a
weighted average of the age-specific rates, for each of the populations to be compared.
The weights applied represent the relative age distribution of the arbitrary external
population (the standard). This provides, for each population, a single summary rate that
reflects the number of events that would have been expected if the populations being
compared had had identical age distribution. Symbolically, the directly standardized
mortality rate for populations A and B are given by the following equations:
where nis is the mid-year population in the ith age group of the standard population, ria
and rib are the death rates in age group i in populations A and B, respectively. The ratio of
two such standardized rates is referred to as the Comparative Mortality Ratio (CMR), a
very useful measure. If the age-specific rates in the populations being compared have a
roughly consistent relationship from one age group to the next, the selection of a standard
population will not substantially affect comparisons among groups or time periods. In
reality, however, the relative differences are usually not constant from one age group to
another. As such, both the comparison as well as the conclusions drawn are influenced
by the chosen standard.
In this paper, we review the existing standard populations currently in use for
international comparison, the Segi (“world”) and the Scandinavian (European) standard
populations. Based on this review, a new WHO World Standard age-structure is
presented for epidemiological comparisons using the direct approach. The age
composition of the new standard has been chosen to better reflect the future age structure
of the worlds population for which comparative rates will be needed.
History of Direct standardization
By the middle of the nineteenth century, public health practitioners in England had began
to recognize that simple crude rates were inappropriate summary measures for comparing
population health when the age distribution of the geographic areas were markedly
different. Discussions centered around the development of a summary mortality index
free from the effect of age differences. In a paper he read to the Statistical Society of
London, Sir Edwin Chadwick, one of the early public health reformers in England,
proposed the use of the mean age at deathas a summary measure for comparing the
health condition of the various sanitary districtsaround London (Finer, 1952; Lewis,
1991). This index, he argued, represented a true summary of the age-specific risks of
dying. In response, Neison, a practicing actuary, disagreed with Chadwicks underlying
logic. He argued that since mortality increased with age, Chadwicks mean age at death
for geographic areas with a relatively older population would tend to overstate excess
mortality. In a subsequent article, Neison demonstrated the fallacy in Chadwicks
argument by comparing the crude mean age at death with the mean age computed by a
method of direct standardization (Neison 1844). Neison was, thus, the first to introduced
both the concepts of direct and indirect standardization, as well as the term standard
The Registrar Generals report of 1883 was the first reported use of Neisons direct
standardization method, using the 1881 population census of England and Wales as the
standard (most current at the time). In subsequent reports, the standard was changed each
time there was a new census, i.e., every ten years (Woolsey, et al., 1959; Benjamin, et al.,
1980). These frequent changes of the standard were cumbersome since historical rates
had to be recalculated each time in order to assess current trends. As a solution, the 1901
population census was eventually adopted as a general standard in England and Wales,
and remained unchanged even when a new census became available.
In order to facilitate comparison with mortality rates in England and Wales, the United
States adopted the 1901 British standard. This practice continued until the early 1940s
when it was decided that the difference between the US population at the time and the
1901 English population was significant enough to warrant a change in standard. As a
result, the US adopted its 1940 census population (the most current at the time) as the
new standard. Recently, however, there has been growing concern that the 1940 standard
no longer reflects the increasingly older US age structure. In response, the National
Center for Health Statistics sponsored two national workshops in 1991 and 1997 on the
issue of a new US standard. The final report of these workshops recommended the
adoption of a new standard based on the projected 2000 population age distribution
(NCHS, 1998).
An International Standard Population
The idea of a truly international standard was first suggested by Ogle in 1892. His
proposed standard was an amalgam based on the experience of seven European countries
(Ogle, 1892). There is, however, no evidence of its subsequent adoption for international
comparison by any country. Various standards have been proposed since then but none
adopted widely. The debate has centered largely around the question of whether any one
standard is more suitable than others. This question was discussed at a May 1965
subcommittee meeting of the International Union Against Cancer (IUAC) Conference in
London. Three standard populations were suggested. Each was deemed appropriate for
particular population types. One standard had a high proportion of young people and was
considered appropriate for making comparisons with populations in Africa (Knowelden
and Oettlé, 1962). The second (European) standard was based on the experience of
Scandinavian populations, which contained a relatively high proportion of old people and
was judged particularly suitable for comparison within Western Europe (Doll and Cook,
1967). The third was proposed by Segi (1960) as an intermediate “world” standard based
on the experience of 46 countries. The Europeanand “world” standards were
subsequently adopted by WHO for use in calculating age-standardized death rates. These
standards are shown in Table 1 together with the new WHO World Standard (shown in
abbreviated form for purposes of comparison).
As discussed earlier, the choice of a standard can markedly alter comparisons between
populations. Table 2 shows a time series of circulatory disease mortality among US
males for the period 1970-1995 using the three standards (Segi, Scandinavian and the
WHO World Standard). Even though the overall percentage decline from 1970 to 1995
is almost the same for all three standards (48-49%), the relative differences in the
standardized rates, using the WHO standard as baseline, varies from 20% in one
standard to +24% in the other. Table 3 compares twenty countries on the standardized
death rates for respiratory infections as well as the ranking of countries according to
rates. In general, the Scandinavian standard tends to yield rankings that are closer to
those obtained with the WHO World Standard. In about half the cases, there are only
minor differences in ranking between the three standards. In other cases, however,
substantial shifts in ranking occur when the standard is changed. For instance, the
Russian Federation ranks 9th on the Segi but 13th on the Scandinavian and WHO
standards. Similarly, Cuba ranks 10th on the Scandinavian, 11th on the WHO and 14th on
the Segi. The differences in the actual rates are even more dramatic. The age-
standardized mortality rate for respiratory infections for Hong Kong ranges from 44.9
using the Segi standard to 76.9 using the Scandinavian (European). Much larger
differences are evident in some of the other countries. If the choice of a population
standard for direct age-standardization can have such marked influence on comparisons
over time and between populations, how should a world standard be selected?
A New WHO World Standard Population
Age-structure varies tremendously across populations of the world at different levels of
the demographic transition. Should one, therefore, choose a standard population with
higher proportions in the younger age groups (thereby weighting events at these ages
disproportionately), or choose an older standard, or rather something in-between? There
is clearly no conceptual justification for choosing one standard over another, hence the
choice will eventually be arbitrary. Whatever standard is chosen should ideally be
maintained for a number of years, during which time the age-structure of populations will
alter. For this reason, attempting to match a particular standard to current population age
structures is insufficient justification for choosing one standard over another. Hence,
rather than selecting a standard to match the current age-structure of some population(s),
the standard must be chosen to reflect the average age-structure of all populations to be
compared over the period of use.
The approach proposed by WHO is to base the standard on the average age-structure of
those populations to be compared (the world) over the likely period of time that a new
standard will be used (some 25-30 years). The United Nations Population Division
carries out two-yearly comprehensive assessment of population age-structure for each
country by age and sex (the latest assessment is for 1998 - UN Population Division,
1998). Estimates are prepared for countries for each quinquinnial year from 1950 and
projected to 2025, based on population censuses and other demographic sources, adjusted
for enumeration errors. From these estimates, an average world population age-structure
is constructed for the period 2000-2025. Figure 1 shows the expected evolution of the
worlds population age-structure over the first quarter of the 21st century, and the average
composition which defines the new WHO World Standard.
The use of an average world population, as well as a time series of observations removes
the effects of historical events such as wars and famine on population age composition.
Table 4 gives the percentage of the population in each 5-year age group in the new WHO
World Standard population. Given the rapid and continued declines in age-specific
mortality rates among the oldest old, and the increasing availability of epidemiological
data for higher age groups, the terminal age group in the new standard population has
been extended out to 100 years and over, rather than the 85 and over as is the current
practice. The difference with respect to the Segi and Scandinavian standards can be seen
in Figure 2. The WHO World Standard population has fewer children and notably more
adults aged 70 and above than the Segi standard. It is also notably younger than the
Scandinavian standard. Implementation of this new standard will facilitate international
comparative analysis and reduce confusion among data users.
To facilitate comparisons of sets of age-specific epidemiological and demographic rates
across populations with different age composition, it is useful to calculate summary
health statistics which remove the effects of variation in age structure. The dominant
method currently in use is the direct age-standardization of rates using an arbitrary
standard population. National (as exemplified by the United Kingdom and the United
States) and international experience suggest that population standards have been adopted
for arbitrary reasons and once adopted have been used for many decades. Given current
WHO initiatives, which involve comparisons of vastly different populations, existing
standards appear too extreme. We present a new WHO World Population Standard which
is especially defined to reflect the average age structure of the worlds population
expected over the next generation, from the year 2000 to 2025. Comparisons across
populations of the world should preferably be based on an average world population age
structure and that average age structure should correspond to the period of likely use of a
standard (20-30 years).
To facilitate comparisons globally, all age-standardized rates produced by WHO will be
made according to the new WHO World Standard Population. Hopefully, this single
standard will be widely adopted for global comparisons.
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Table 1. Standard Population Distribution (percent)
Age group Segi (“world”) standard Scandinavian (“European) standard WHO World Standard*
0-4 12.00 8.00 8.86
5-9 10.00 7.00 8.69
10-14 9.00 7.00 8.60
15-19 9.00 7.00 8.47
20-24 8.00 7.00 8.22
25-29 8.00 7.00 7.93
30-34 6.00 7.00 7.61
35-39 6.00 7.00 7.15
40-44 6.00 7.00 6.59
45-49 6.00 7.00 6.04
50-54 5.00 7.00 5.37
55-59 4.00 6.00 4.55
60-64 4.00 5.00 3.72
65-69 3.00 4.00 2.96
70-74 2.00 3.00 2.21
75-79 1.00 2.00 1.52
80-84 0.50 1.00 0.91
85+ 0.50 1.00 0.63
Total 100.00 100.00 100.00
* For purposes of comparison, the WHO Standard age group 85+ is an aggregate of the age groups 85-89, 90-94, 95-99
and 100+.
Table 2. Trend in Age-adjusted Circulatory Disease Mortality Rates Based on the Segi, Scandinavian and WHO
World Standard Populations and the Cumulative Death Rates - US Males (1970-1995)
Rates per 100,000
Standard 1970 1975 1980 1985 1990 1995 % Change 1970-1995
Segi 459.5 399.0 350.3 305.8 256.8 232.3 -49.4
WHO World 550.9 482.2 426.7 373.7 315.0 285.4 -48.2
Scandinavian 720.1 630.4 557.8 488.4 411.6 372.4 -48.3
Percent Difference in Rates Relative to WHO World Standard
Segi -20% -21% -22% -22% -23% -23%
Scandinavian 23% 24% 24% 23% 23% 23%
Table 3. Directly standardized male death rates from respiratory infections
and ranking of twenty countries using three different standard populations - (Around 1995)
Rates Per 100,000 Ranking of Countries ( by age-adjusted death rates)
Segi Scandinavian WHO World Segi Scandinavian WHO world
Australia 6.3
Barbados 28.8
Bulgaria 34.2
Canada 14.5
Cuba 27.2
Estonia 27.5
Germany 11.0
Hong Kong 44.9
Hungary 9.6
Iceland 26.9
Ireland 37.0
Japan 37.8
Latvia 29.5
Luxembourg 8.4
Mauritius 45.2
New Zealand 15.3
Portugal 21.0
Russian Federation 32.7
Singapore 71.9
Spain 10.9
Trinidad and Tobago 30.2
Turkmenistan 114.2
Uzbekistan 80.6
Table 4. WHO World Standard Population Distribution (%),
based on world average population between 2000-2025
Age group World Average 2000-2025
0-4 8.86
5-9 8.69
10-14 8.60
15-19 8.47
20-24 8.22
25-29 7.93
30-34 7.61
35-39 7.15
40-44 6.59
45-49 6.04
50-54 5.37
55-59 4.55
60-64 3.72
65-69 2.96
70-74 2.21
75-79 1.52
80-84 0.91
85-89 0.44
90-94 0.15
95-99 0.04
100+ 0.005
Total 100
Figure 1. World population by age group in percent of total population
2000 to 2025 and average of 2000 to 2025
0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69
age group
percent of total population
Figure 2. Comparison of "Segi" and "Scandinavian" standards with world 2000-2025 average
0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59
Age group
percent difference with world 2000-2025 average population
Segi standard population
Scandinavian standard population
... A variety of factors must be considered when a population-wide cancer-screening program is set in place, the most important of which are the country's demographic profile and the local burden of the disease of interest. In this context, the age-standardized incidence rate (ASR) is a commonly used parameter that characterizes the different risk levels in a given population [15]. In terms of GC, three risk areas can be determined ( Figure 1) [16]: GC remains a highly heterogeneous disease from both morphological and molecular standpoints [4]. ...
... A variety of factors must be considered when a population-wide cancer-screening program is set in place, the most important of which are the country's demographic profile and the local burden of the disease of interest. In this context, the age-standardized incidence rate (ASR) is a commonly used parameter that characterizes the different risk levels in a given population [15]. In terms of GC, three risk areas can be determined ( Figure 1) [16]: High-risk areas: ASR ≥ 20 per 100,000 person-years (p-y), e.g., Japan, Korea, and China. ...
... From premalignant lesions to early gastric cancer-What is clinically relevant? Rouen: Le Grand Métier, 2021: [15][16][17][18][19][20][21][22][23][24][25] and was created with the permission of the publisher and Chief Editor of the book. ...
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Background: Gastric cancer (GC) remains the fifth most common cancer and the third most common cause of cancer-related death globally. In 2022, GC fell into the scope of the updated EU recommendations for targeted cancer screening. Given the growing awareness of the GC burden, we aimed to review the existing screening strategies for GC in high-risk regions and discuss potentially applicable modalities in countries with low-to-intermediate incidence. Methods: The references for this Review article were identified through searches of PubMed with the search terms "gastric cancer", "stomach cancer", "Helicobacter pylori", and "screening" over the period from 1995 until August 2022. Results: As Helicobacter pylori (H. pylori)-induced gastritis is the primary step in the development of GC, the focus on GC prevention may be directed toward testing for and treating this infection. Such a strategy may be appealing in countries with low- and intermediate- GC incidence. Other biomarker-based approaches to identify at-risk individuals in such regions are being evaluated. Within high-incidence areas, both primary endoscopic screening and population-based H. pylori "test-and-treat" strategies represent cost-effective models. Conclusions: Given the significant variations in GC incidence and healthcare resources around the globe, screening strategies for GC should be adjusted to the actual conditions in each region. While several proven tools exist for accurate GC diagnosis, a universal modality for the screening of GC populations remains elusive.
... 59, 60-64, 65-69, and 70 years old and over), and sex (male or female). Meanwhile, morbidity and mortality rates by 100,000 were also calculated in different regions (National Capital Region, Cordillera Administrative Region, Region I, Region II, Region III, Region IV-A (CALABARZON), Region IV-B (MIMAROPA), Region V, Region VI, Region VII, Region VIII, Region IX, Region X, Region XI, Region XII, Region XIII (CARAGA), and Bangsamoro Autonomous Region in Muslim Mindanao (BARMM) from 1960-2019[11],[12]. ...
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p>Despite initiatives to address the disease, rabies remains a public health threat in the Philippines. To determine the trend of rabies infections in the country and provide possible interventions to reduce or eliminate deaths of the affected, we evaluated rabies morbidity and mortality statistics over sixty years. Over the last six decades, rabies mortality rates in the Philippines have steadily decreased. The Philippines' rabies sex-specific mortality rate trend from 1960 to 2019 showed that males account for higher rabies mortality than females. People aged 70 and up have the highest mortality rate, while children under the age of 1 have the lowest. The region with the highest mortality rate in the Philippines is region II (Cagayan Valley), with 39.5. The region with the highest morbidity rate is XI (Davao region), with 148.7. The correlation value was 0.197, indicating a weak correlation between regional morbidity and mortality rates in the Philippines over the years. Hence, those who have contracted rabies are less likely to die over time. Comprehensive control measures by both the national and local government units should be strengthened to eliminate rabies in the Philippines within the next few years.</p
... And the proportions of those aged over 60 and over 65 accounted for 16.7% and 10.8% of the population, respectively, 35 which is higher than the proportions of 11.96% and 8.24% of the WHO world standard population. 36 Consistent with previous reports, our study found that the proportion of those aged over 60 had risen from 9.5% in 1997 to 16.1% in 2016. Meanwhile, the proportion of those aged below 15 decreased from 25.7% to 15.1%. ...
Objective: To evaluate the trends in disease burden and the epidemiological features of liver cancer in China while identifying potential strategies to lower the disease burden. Design: Observational study based on the Global Burden of Diseases. Participants: Data were publicly available and de-identified and individuals were not involved. Measurement and methods: To measure the liver cancer burden, we extracted data from the Global Health Data Exchange using the metrics of prevalence, incidence, mortality and disability-adjusted life years (DALYs). Joinpoint and negative binomial regressions were applied to identify trends and risk factors. Results: From 1997 to 2016, the prevalence, incidence, mortality and DALYs of liver cancer in China were from 28.22/100 000 to 60.04/100 000, from 27.33/100 000 to 41.40/100 000, from 27.40/100 000 to 31.49/100 000 and from 10 311 308 to 11 539 102, respectively. The prevalence, incidence and mortality were increasing, with the average annual percent changes (AAPCs) of 4.0% (95% CI 3.9% to 4.2%), 2.1% (95% CI 2.0% to 2.2%) and 0.5% (95% CI 0.2% to 0.9%), respectively. Meanwhile, the rate of DALYs was stable with the AAPCs of -0.1% (95% CI -0.4% to 0.3%). The mortality-to-incidence ratio of liver cancer decreased from 1.00 in 1997 to 0.76 in 2016 (β=-0.014, p<0.0001). Males (OR: 2.98, 95% CI 2.68 to 3.30 for prevalence, OR: 2.45, 95% CI 2.21 to 2.71 for incidence) and the elderly individuals (OR: 1.57, 95% CI 1.55 to 1.59 for prevalence, OR: 1.58, 95% CI 1.56 to 1.60 for incidence) had a higher risk. Hepatitis B accounted for the highest proportion of liver cancer cases (55.11%) and deaths (54.13%). Conclusions: The disease burden of liver cancer continued to increase in China with viral factors as one of the leading causes. Strategies such as promoting hepatitis B vaccinations, blocking the transmission of hepatitis C and reducing alcohol consumption should be prioritised.
... We initially calculated age-standardized rates and truncated rates at 45 to 64 years old by sex using the direct method, with the world population as standard. 15 To graphically demonstrate the temporal trends in liver cancer, we plotted the incidence trends using both the observed data and locally weighted regression (lowess) smoothed data. 16,17 To identify significant changes in the slopes of overall incidence trends, we used joinpoint regression, 18 which involves fitting a series of joined straight lines to incidence rates. ...
Background & aims: We examined temporal trends in liver cancer incidence rates overall and by histological type from 1983 through 2007. We predict trends in liver cancer incidence rates through 2030 for selected Eastern and Southeastern Asian countries. Methods: Data on yearly liver cancer incident cases by age group and sex were drawn from 6 major selected Eastern and Southeastern Asian countries or regions with cancer registries available in the CI5plus database, including China, Japan, Hong Kong Special Administrative Region (SAR), the Philippines, Singapore, and Thailand. We also analyzed data for the United States and Australia for comparative purposes. Age-standardized incidence rates were calculated and plotted from 1983 through 2007. Numbers of new cases and incidence rates were predicted through 2030 by fitting and extrapolating age-period-cohort models. Results: The incidence rates of liver cancer have been decreasing, and decreases will continue in all selected Eastern and Southeastern Asian countries, except for Thailand, whose liver cancer incidence rate will increase due to the increasing incidence rate of intrahepatic cholangiocarcinomas. Even though the incidence rates of liver cancer are predicted to decrease in most Eastern and Southeastern Asian countries, the burden, in terms of new cases, will continue to increase because of population growth and aging. Conclusions: Based on an analysis of data from cancer registries from Asian countries, incidence rates of liver cancer are expected to decrease through 2030 in most Eastern and Southeastern Asian countries. However, in Thailand, the incidence rate of intrahepatic cholangiocarcinomas is predicted to increase, so health education programs are necessary.
Colorectal cancer (CRC) is a leading cancer worldwide; incidence varies greatly by country and racial group. We compared 2018 American Indian/Alaska Native (AI/AN) CRC incidence rates in Alaska to other Tribal, racial, and international population rates. AI/AN persons in Alaska had the highest CRC incidence rate among US Tribal and racial groups (61.9/100,000 in 2018). AI/AN persons in Alaska also had higher rates than those reported for any other country in the world in 2018 except for Hungary, where males had a higher CRC incidence rate than AI/AN males in Alaska (70.6/100,000 and 63.6/100,000 respectively). This review of CRC incidence rates from populations in the United States and worldwide showed that AI/AN persons in Alaska had the highest documented incidence rate of CRC in the world in 2018. It is important to inform health systems serving AI/AN persons in Alaska about policies and interventions that can support CRC screening to reduce the burden of this disease.
Objectives: To generate contemporary age-specific mortality rates for Indigenous and non-Indigenous Australians aged <65 years who died from rheumatic heart disease (RHD) between 2013 and 2017, and to ascertain the underlying causes of death (COD) of a prevalent RHD cohort aged <65 years who died during the same period. Methods: For this retrospective, cross-sectional epidemiological study, Australian RHD deaths for 2013-2017 were investigated by first, mortality rates generated using Australian Bureau of Statistics death registrations where RHD was a coded COD, and second COD analyses of death records for a prevalent RHD cohort identified from RHD register and hospitalisations. All analyses were undertaken by Indigenous status and age group (0-24, 25-44, 45-64 years). Results: Age-specific RHD mortality rates per 100 000 were 0.32, 2.63 and 7.41 among Indigenous 0-24, 25-44 and 45-64 year olds, respectively, and the age-standardised mortality ratio (Indigenous vs non-Indigenous 0-64 year olds) was 14.0. Within the prevalent cohort who died (n=726), RHD was the underlying COD in 15.0% of all deaths, increasing to 24.6% when RHD was included as associated COD. However, other cardiovascular and non-cardiovascular conditions were the underlying COD in 34% and 43% respectively. Conclusion: Premature mortality in people with RHD aged <65 years has approximately halved in Australia since 1997-2005, most notably among younger Indigenous people. Mortality rates based solely on underlying COD potentially underestimates true RHD mortality burden. Further strategies are required to reduce the high Indigenous to non-Indigenous mortality rate disparity, in addition to optimising major comorbidities that contribute to non-RHD mortality.
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Introduction: Childhood cancer is a small proportion of all cancers but is still a major public health problem. Objective: To describe the 5-year incidence and mortality rates and net survival of childhood cancer in Uruguay. Method: Data on all malignant tumors diagnosed in children aged 0-14 were included for the period 2011-2015, obtained from the National Pediatric Registry of Cancer and from the Ministry of Health Mortality Registry, classified according to the International Classification of Childhood Cancer (ICCC-3). Information on the total population was obtained from national census records. Follow up was made until December 2020. Results: The standardized incidence rate was 128/million children per year. The distribution of the disease was similar to developed countries. The overall mortality rate was 28.2/million, with a net overall survival of 79.6% for the total population. Conclusion: Childhood cancer incidence in Uruguay is similar to developed countries. Progress in diagnosis and care have improved survival immensely, but efforts must continue to keep this trend and ameliorate the outcomes.
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Objetivo: Realizar um levantamento de dados sobre a taxa de mortalidade associada ao câncer de pulmão e brônquios nos municípios da Região de Saúde Sul do Estado de Mato Grosso. Metodologia: Trata-se de um estudo descritivo, retrospectivo de série temporal, no qual se obtiveram os dados sobre o número de óbitos por neoplasia maligna de brônquios e de pulmões em pessoas residentes na Região de Saúde Sul de Mato Grosso, ocorridos entre 2010 e 2019, por meio do Sistema de Informações sobre Mortalidade (SIM), disponibilizados pelo Departamento de Informática do Sistema Único de Saúde (DATASUS). Calculou-se a taxa de mortalidade para os municípios pela razão entre o total de óbitos por câncer de brônquios ou pulmões e a estimativa da população, estratificada por sexo e idade, a cada ano. Utilizou-se o método direto para padronização das taxas de mortalidade por faixa etária. Resultados e Discussão: A partir dos dados disponíveis, verificou-se que 12,49% dos óbitos causados por câncer nos 19 municípios da região foram por câncer de brônquios ou pulmões. A mortalidade foi maior em homens (12,07 óbitos/100 mil) do que em mulheres (7,70 óbitos/100 mil). Ademais, pessoas na faixa de 70 a 79 anos tiveram uma taxa mortalidade maior (104,05 óbitos/100 mil) do que aquelas nas faixas mais jovens. Isso evidencia que ambas as constatações estão de acordo com a literatura. Conclusão: Os dados demonstram uma relação de maior mortalidade associada ao sexo masculino, bem como à idade mais avançada, estando de acordo com a literatura.
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Objectives: to evaluate the temporal trend of hospitalizations for pelvic infammatory disease in Brazil and its regions between 2000 and 2019. Methods: longitudinal ecological study with data from the Hospital Information System. The analysis of temporal trends in hospitalization rates by age group was performed using segmented linear regression (joinpoint regression). Both annual percent change total and by age groups were estimated for Brazil and each region. Results: Brazil had an average reduction of 5.2% per year in the period and the age groups most affected were 20 to 29 and 30 to 39 years. North region had the highest rates and South and Southeast regions, the lowest. Midwest region had the largest annual average reduction (8.1%), followed by the Northeast (5.7%), Southeast (5.0%), North (4.6%) and South (4.3 %). The only age group that showed a significant increase was that of 10 to 19 years in the Southeast in the period from 2008 to 2019 (0.9%) and in the Northeast in the period from 2014 to 2019 (3.3%). Conclusions: hospitalization due to pelvic infammatory disease has significantly decreased in Brazil. The increase observed for adolescents in the Southeast and Northeast in the most recent period points to problems in the prevention and control of sexually transmitted infections in this age group.
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Aims/introduction: We aimed to determine the incidence trend of childhood type 1 diabetes mellitus in Isfahan province over a period of 12 years. Materials and methods: In this retrospective study, children aged <20 years at the time of type 1 diabetes mellitus diagnosis, from March 2007 to March 2019, were included. The crude and adjusted incidence rate of type 1 diabetes mellitus is calculated as the number of cases per 100,000 person-years by the period. The cumulative, age- and sex-specific incidence rates were also calculated. Age-specific incidence rates were calculated for age and sex groups. Results: A total of 1,954 (983 boys and 971 girls) cases of type 1 diabetes mellitus were identified. The mean age at diagnosis in all studied populations was 9.89 (standard deviation 4.76). There were no significant differences between the proportion of boys and girls in different years (P = 0.12) and different age groups (P = 0.19). The average annual percent change of incidence rate for the total population, for girls and boys, was 6.9%, 6.7% and 6.3% respectively. The type 1 diabetes mellitus incidence rate had a significant trend to be increased from 2007 to 2019 (P < 0.001, t = 3.6). Conclusion: Our findings showed that currently our region is considered a region with a high incidence rate of type 1 diabetes mellitus. Although we have had fluctuations in the incidence rate over the 12 years, the overall trend is increasing.
The concepts that case-referent studies provide for the estimation of "relative risk" only if the illness is "rare", and that the rates and risks themselves are inestimable, are overly superficial and restrictve. The ratio of incidence densities (forces of morbidity)-and thereby the instantaneous risk-ratio-is estimable without any rarity-assumption. Long-term risk-ratio can be computed through the coupling of case-referent data on exposure rates for various age-categories with estimates, possibly from the study itself, or the corresponding age-specific incidence-densities for the exposed and nonexposed combined-but again, no rarity-assumption is involved. Such data also provide for the assessment of exposure-specific absolute incidence-rates and risks. Point estimation of the various parameters can be based on simple relationships among them, and in interval estimation it is sufficient simply to couple the point estimate with the value of the chi square statistic used in significance testing.
Morgenstern H [Department of Epidemiology and Public Health, School of Medicine, Yale University, 60 College Street, New Haven, CT 06510], Kleinbaum D G and Kupper L L. Measures of disease incidence used in epidemio-logic research, International Journal of Epidemiology 1980, 9: 97–104. This paper distinguishes between 2 concepts for measuring the incidence of disease: risk and rate. Alternative procedures for estimating these measures from epidemiologic data are reviewed and illustrated. An attempt is made to integrate statistical principles with epidemiologic methods while minimizing the use of higher mathematics. Several theoretical and practical criteria are discussed for choosing the appropriate incidence measure in the planning of a study and for selecting the best method of estimation in the analysis.
The desirability of achieving agreement on a method of summarizing cancer incidence is emphasized, and the advantages and disadvantages of the use of the traditional standardized incidence rates are discussed.It is concluded that: 1No single index is capable of replacing the individual sex- and age-specific incidence rates, and these should always be presented when basic cancer incidence data are published.2For aetiological studies age-specific incidence rates can usefully be summarized in two indices, one (a truncated standardized incidence) showing a standardized incidence over a restricted age range, and the other indicating the rate at which cancer incidence increases with age.3An appropriate truncated rate for most epithelial cancers is one for the age range of 35 to 64 years, using weights of 6, 6, 6, 5, 4 and 4 for the individual 5-year age groups, derived from Segi's (1960) world standard population. For other cancers, age ranges of 0 to 14 years and of 0 to 44 years would be more suitable, with weights of 12, 10 and 9, and 12, 10, 9, 9, 8, 8, 6, 6 and 6 for the corresponding 5-year age groups.4An indication of the general character of a given set of incidence data may be obtained by calculating the ratio of the rates at ages 55 to 64 years and at 35 to 44 years for a combined group of cancers that normally increase rapidly in incidence with age.5Further research on practicable ways of indicating the shape of the age-incidence curve for individual types of cancer is required.
The Analysis of Case-Control Studies
In: Statistical Methods in Cancer Research, Vol. I, The Analysis of Case-Control Studies (IARC Scientific Publications No. 32), Lyon, International Agency for Research on Cancer, 1980. pp.42-81.