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Unité d'Enseignement et de Recherche en Démographie, Ouagadougou, Burkina Faso, 12-14 February 2004
Session 1. General perspectives
Session 1 provided a transition from the first seminar on "Determinants of Diverging Trends in Mortality". The first paper by K. Moser, V. Shkolnikov and D. Leon Mortality of the world's population 1950-2000: divergence replaces convergence from the late 1980s demonstrated that life expectancy at birth has converged worldwide up to late 1980s before starting to diverge due to increases in adult-age mortality. This new trend constitutes a major challenge to the general expectation of convergence towards a low mortality regime based on existing concepts of epidemiological transition. J. Vallin and F. Meslé in their paper, Convergences and divergence in mortality: A new approach to health transition, showed that the Abdel Omran's original epidemiologic transition theory can be integrated into a broader scheme. This scheme takes into account all recent changes in mortality patterns, both favourable and unfavourable. The transition includes three stages: vanquishing infectious disease (Omran's epidemiologic transition), the cardiovascular revolution and the fight against aging. Different countries and regions could simultaneously face different stages of the transition or a combination of transitions. While the most developed countries are passing from the second to the third stage, many developing countries have not completed the first stage.
The discussion that followed focused on methodological issues, especially the
comparability of the data used. The data are of different quality and were obtained
through different methods. For example data on mortality during the 1950s and
1960s from sub-Saharan Africa were obtained through very simple models. The
need to look at the urban/rural and sub-regional differential and at the historical
context of the decrease of infant mortality in Africa was also stressed. The
authors explained that the differential in the quality of data does not affect
the big picture portrayed by their papers. The differential in the quality of
data was more substantial in the past, at a time when this differential cannot
solely account for the observed worldwide divergence in life expectancy at birth.
The study of the divergence of mortality actually provides a tool to measure
the amount of inter-country diversity in mortality.
Session 2. Evidence from demographic surveillance in Africa - 1
Two papers were presented: by Ian Timæus on Impact of HIV on mortality
in Southern Africa: Evidence from demographic surveillance and by Judith
Glynn on The impact of HIV infection on tuberculosis in Africa.
Using data from several demographic surveillance sites, Timæus found a
similarity in age patterns of AIDS mortality in the local populations from Zimbabwe,
South Africa, Tanzania, and Namibia. It allowed him to develop a simple one-parameter
model for predicting age-specific mortality due to AIDS. Timæus' model
can be used to estimate the mortality effects of AIDS, wherever direct mortality
data are not available or unreliable. However, it is worth noting that the resulting
estimates would depend on contextual characteristics at different settings.
Differences may exist in behaviours even though no differences are found in
mortality.
Tuberculosis (TB) notification rates have doubled in Africa since the mid-1980s.
J. Glynn found that the risk of TB greatly increases due to HIV infection at
an individual and population level. Incidence of TB increases with rising HIV-infection
rates and will continue to increase for some time even after a fall in HIV incidence
due to the long latent period of HIV. Antiretroviral medications can decrease
the risk of TB, but would have to be used early and extensively to have a large
effect at the population level.
Session 3. Evidence from demographic surveillance in Africa - 2
This session focused on HIV and AIDS related deaths in Zimbabwe (HIV in Zimbabwe
by O.Mugurungi, S. Gregson et al.) and Uganda (Demographic patterns of
AIDS deaths and differences in willingness to have more children in rural southwest
Uganda by L. Muhangi).
In Zimbabwe, sexual networks shaped by cultural and colonial influences and
the relatively high but uneven level of development have facilitated the spread
of HIV after the mid-1980s. It was rapid and by the mid-1990s about one quarter
of the adult population was infected. The epidemic caused crisis-level adult
mortality particularly in the most active ages, a reversal of prior gains in
child survival, a rapid decline in population growth, and an increase in the
number of orphans. A rapid response to the epidemic brought some positive changes
in the behaviours since the late 1990s and seems to have levelled off infection
rates.
Uganda is one of Africa's success stories. For example, between 1986 and 2001
HIV prevalence dropped from 30 to 6 percent in southwest Uganda due to behavioural
changes. Muhangi's paper demonstrated behavioural changes among HIV positive
individuals. Demographic surveillance data from the district of Masaka in southwest
rural Uganda showed a high frequency of premature deaths from AIDS. HIV positive
individuals were more likely than HIV negative individuals to express the intent
to have no more children. Despite the stated intent of many HIV positive individuals
to have no more children, the desire for more children remained high for a large
percentage of the HIV positive informants.
Discussion following the presentation of papers focused on methodological issues.
There was a concern about possible underestimation of the infant mortality increase
in Zimbabwe. The reliability of the cause of death classification and of census
data used in Zimbabwe raised concern and may account for part of the observed
differences between urban and rural areas. With regards to the Uganda paper,
the participants expressed some concerns about data quality and pointed to the
desirability to consider temporal changes rather than simply cross-sectional
comparisons. The author replied that his findings were preliminary and the study
will be developed further.
Session 4. Country case studies
In this session three country case studies were presented for Burkina Faso, South Africa, and Madagascar: Population et maladies infectieuses au Burkina Faso by B.Baya, Multiple causes of death statistics and HIV/AIDS in South Africa: their changing profile over the period 1997 to 2001 and utility in the era of HIV/AIDS, by S.Bah and Disparition et émergence des décès infectieux et parasitaires à Tananarive by D. Waltisperger.
Baya showed that infectious diseases constitute a large part of mortality and
morbidity in Burkina Faso. They result in heavy economic losses due to long
periods of disability and premature deaths. Baya argued that the spread of infectious
diseases was facilitated by health-related factors--inefficient health system,
underutilization of healthcare facilities by the population--and by non health-related
factors--lack of resources, poor nutritional status, poor water supply, environment
modification, and lack of education. Discussions following the paper suggested
that the implementation of the 1987 Bamako Initiative removing the free-of-charge
policy regarding health services and widespread poverty explain the underutilization
of healthcare facilities by the population. Baya suggested that one solution
would be to revise the Bamako Initiative and reduce health fee charges. He also
recommended resorting to the community-based approach, e.g. the training of
community health agents to implement the malaria programme. Since health systems-based
data represent only one twelfth of all deaths that occurred in Burkina Faso,
he was advised to also use population-based data from the Nouna observatory.
Bah studied mortality in South Africa using death records listing multiple causes
of death. The analysis revealed that TB, influenza and pneumonia played important
roles as contributing causes of death. It could be possible, in the future,
to estimate the real impact of HIV/AIDS on mortality and misreporting by using
regression models. Participants expressed methodological concerns regarding
the completeness of death reporting and the problem of selectivity of the sample
used by Bah in South Africa.
In Africa mortality data are usually insufficient for building continuous time
series analyses. Waltisperger used a unique collection of mortality data from
Tananarive to create a time series analysis of mortality by cause-of-death.
Systematic analysis showed epidemiological evolution in Madagascar and revealed
exceptional mortality increases in 1987 which he attributed to famine. Further
research is however needed to understand what exactly happened in 1987. The
author's explanation that the increase in mortality was due to famine was unclear.
Drops in life expectancy at birth in Tananarive were smaller than those caused
by past famines in Finland and Ukraine. It is not clear also why mortality effect
was so much greater for men than for women.
Session 5. Country case studies
Papers presented during this session discussed the relationship between population movement and HIV/AIDS in Africa (Population movement and the AIDS epidemic in Africa by J.Anarfi) and more specifically, the relationships between migration and knowledge and perception of HIV/AIDS in Northern Senegal (L'expérience migratoire face à la connaissance et les perceptions relatives au VIH/SIDA. Le cas de la vallée du fleuve Sénégal by F.Waitzenegger-Lalou, V.Piché and R. Lalou).
Anarfi summarized migratory flows in Africa and showed how these flows contribute
to the spread of HIV/AIDS. Migration in Africa is circular and does not lead
to permanent removal from one's place of origin. Until migrants finally return,
they repeatedly visit their homes creating fertile grounds for the spread of
STDs. HIV spreads geographically via people's relocation. Mobile people are
more involved in risky sexual behaviors. They are exposed to especially unfavorable
conditions such as physical and psychological stress and do not have access
to adequate healthcare facilities. Women also increasingly take part in migratory
movements though with fewer economic opportunities, many migrant women become
involved in commercial sex work.
Waitzenegger-Lalou et al. showed that migrants from Northern Senegal who travelled
to cities better covered by anti-aids campaigns or to areas severely affected
by HIV did not increase their knowledge about HIV/AIDS. However, migrants who
stayed in a country with a high HIV prevalence or who had engaged in risky behaviours
during migration did have an increased self-perception of being at risk. The
discrepancy between knowledge and perception stems from the fact that AIDS is
not only a radio message, but also a reality of every day life, especially in
Matam, one of the areas studied.
Comments following the presentations suggested it was necessary to move beyond
migration and migrants to introduce a contextual approach, which requires a
shift from the individual level to the state level. The situation of Algeria
- a country with high population mobility, protracted civil unrest and lack
of an AIDS education program, but yet curiously without an HIV outbreak defies
the hypotheses that migration itself accelerates the epidemic. Anarfi attributed
the Algerian exception to the fact that Algerian migration is directed to a
country with low levels of HIV (France), a good healthcare system, less dramatic
levels of poverty than elsewhere in the developing world, and the role of Islam,
which prevented widespread risky sexual behaviours. However, he emphasized that
migrants can import HIV, as was the case of Ghanaian female migrants to Cote
d'Ivoire. He also argued that the cause of the escalation of the AIDS epidemic
in South Africa is the failure to recognize the seriousness of the disease along
with high levels of extra-marital sex. Lalou pointed out that Northern Senegal
was not a priority in the anti-AIDS campaign in Senegal, despite a serious problem
of sexually transmitted diseases in the area and early research findings that
linked international labour migration to HIV spread in the region. Migrants
perceive themselves to be at risk of being contaminated but not to be at risk
of contaminating others.
Session 6. Socio-economic conditions and infectious disease
The three papers presented during this session challenged widespread wisdom and called into question popular consensus concerning the impact of the HIV/AIDS epidemic. They respectively dealt with Poverty and social exclusion by M. Turshen, Development and infectious disease: the case of HIV in Africa by J. Decosas and Conséquences économiques des maladies infectieuses by J. Brunet-Jailly.
Turshen's paper questions the assumption that HIV/AIDS leads to social exclusion in Africa and the very applicability of the concept of social exclusion as it is currently understood to Sub-Saharan Africa. This paper suggests that it is not HIV/AIDS that leads to social exclusion but rather the current economic, political, and social dislocation that may be driving the HIV/AIDS epidemic and other resurgent infections in Africa.
Decosas' paper considers the complex relationship between the HIV epidemic and development in Africa. Although according to some models, the spread of AIDS could lead to the erosion of human capital; there is, however, no evidence of major effects on macro-economic performance and educational level. Social cohesion, which was been seriously affected at early stages of the epidemic, seems to be much less affected at its later stages. Social capital is being created, though it can be easily broken in societies facing famines, wars or severe political exploitation. In general, there is no reason why HIV would stop the African renaissance in the 21st century.
Brunet-Jailly proposed a cost-benefits approach to ranking priorities for resource allocation. Resource allocation should maximize the benefits for the general health status of the population rather than giving automatic priority to a single disease (e.g. AIDS) and advocating for expensive treatments for its victims. Local communities must participate in the decision-making process and make their own choices concerning the allocation of health resources.
The discussion following the paper presentations, focused on the utility of the concept of social exclusion in the context of sub-Saharan Africa, its definition by African communities themselves and its link to HIV. It was recognized that some social organizations take care of infected people in Africa and that there is more acceptance of HIV/AIDS victims as the epidemic matures. It was argued that using volume of the production rather than GDP would highlight the economic impact of AIDS. Studying the case of malaria would also help to gain insight in the economic impact of infectious diseases.
Criticism of Brunet-Jailly's paper stressed that the cost-benefit approach assumes a tight upper limit of resources. This assumption is questionable. As an example, the Secretary General of the UN has managed to gather two billion dollars for the world fund against AIDS. This demonstrates that the funds do exist and can be raised. The author stressed that it is necessary to have a cost-benefit approach to healthcare even though it is a common good.
Session 7. Development, environmental change and infectious disease
This session dealt with the inter-relations between environmental change, agriculture, population growth, and infectious disease. Three papers were presented: Climate change and infectious disease by A. Githeko, Some considerations on inter-relations between agriculture, infectious diseases and HIV/AIDS by J. du Guerny and Population Growth and infectious disease by G. Garnett and J. Lewis.
According to Githeko, the effects of climate change and variability are expressed
in short-term epidemics and could lead to long-term changes in disease epidemiology.
Up to 50 percent of the anomalies in hospital based highland malaria cases in
Kenya can be connected to changes in meteorological conditions. Meteorological
data can be used for a precise forecasting of disease outbreaks. Climate variability
has the potential to precipitate simultaneous and multiple disease epidemics.
During the discussion, Githeko argued that his model could be used to predict
epidemics. Health professionals are, however, usually sceptical about models,
especially when they do not use hospital-based data. There is a need to educate
policy-makers about the usefulness of this model as a tool for planning vaccination
campaigns.
Du Guerny focused on farming systems to demonstrate that HIV/AIDS has an impact
on agriculture production by affecting the availability, quality and cost of
the labour force. So far, the importance of this inter-relationship has been
poorly recognised. Du Guerny also explained that irrigation may have a great
impact on some infectious diseases like malaria. Improper use of fertilizers
and insecticide may also cause problems.
Garnett and Lewis proposed a general model mapping the relationship between
population density, the spread of infectious disease and its consequences (e.g.
mortality). They argued that population growth has three major consequences
for infectious disease: (1) the sheer scale of cities provides more opportunities
for disease to persist by providing a large supply of susceptible individuals.
(2) Growing population and poverty produce increasing contact rates creating
conditions for epidemics. (3) Travel and migration increase global contacts
turning epidemics into pandemics. Infectious diseases, in turn, increase death
rates amongst young people with potential to reverse the epidemiologic transition.
In respect to the communication by Lewis, it was noted that it would be interesting
if the model were directly applied to sub-Saharan Africa. However, data availability
could be a problem. For example, modelling the spread of HIV would require data
on sexual networks.
Session 8. Socio-cultural factors and AIDS
Paul Nkwi et al. examine the reasons why many cultural practices conducive to HIV infection still persist in sub-Saharan Africa despite education and awareness campaigns in their paper The impact of socio-cultural practices on the spread of HIV/AIDS in selected countries. The study is based on contextual analysis of descriptions of various social-cultural practices from Côte d'Ivoire, Togo, Cameroon, Kenya, and Malawi within the framework of an African Population Advisory Council study. The following practices were considered: initiation rituals, widow inheritance (levirate), bodily scarification, female genital cutting, male circumcision, funeral rites including indiscriminate sex. They noted that behavioural change can only occur if norms and values at the societal level are understood as well as the way individuals internalize them and act on them in their daily life. The discussion pointed out that cultural approaches prevalent during late 1980s and early 1990s had serious limitations. The cultural changes they promoted were difficult to achieve. Another problem is how to measure cultural change. Nkwi emphasised that one has to go to the community in order to understand the rationale behind the cultural practices and then let the community find and propose the solutions to the threat posed by the HIV epidemic and initiate changes in their cultural practices.
E. Slaymaker analysed data from nationally representative surveys of 1996 and 2001-2 in the paper: Sexual Behaviour and HIV prevalence in Zambia 1996 to 2002. This paper showed that sexual risk behaviours have become less common and marital dynamics are changing. Never married male informants reported decreases in sex with more than one partner and sex at age under 15. Re-marriage of men has become more common. At the same time, prevalence of HIV was stable between 1996 and 2001. She suggested that HIV prevention efforts should pay more attention to married people.
Session 9. Successes and failures in disease control. What lessons can be learned?
Two papers were presented during this session: Pourquoi la mortalité des enfants ne baissent-t-elle plus depuis une quinzaine d'années en Afrique au sud du Sahara ? by G. Pison and Determinants and dynamics of the sexual transmission of HIV in sub-Saharan Africa: implications for HIV control by M. Caraël and K. B. Nsarhaza.
Pison presented results of a systematic analysis of demographic surveillance
data on mortality trends by cause of death from rural Senegal. He showed that
during the last fifteen years child mortality has no longer decreased and that
this reversal in mortality trends is not solely due to HIV/AIDS. The study attributes
the reversal in rural Senegal to a slackening of the immunization campaign and
to an increase of malaria prevalence due to chloroquine resistance. In the discussion,
participants pointed to the experiences of African countries other than Senegal
and biases in structural adjustment programs were identified as being responsible
for the worsening in child mortality. In Niger for example, this bias led to
an increase in the antenatal care visits in the rural areas and a decrease in
the capital city Niamey.
The study by Caraël and Nsarhaza of HIV/AIDS in four cities in sub-Saharan
Africa demonstrated that the course of the epidemic depends on numerous inter-related
factors. A broad explanatory framework was considered. It included structural
determinants such as demographic trends and urbanization, political and economic
change, cultural factors (education, male circumcision, attitudes towards the
disease, and gender inequality) and proximate determinants connected with certain
characteristics of sexual networks. The discussion of Caraël's presentation
focused on sexual initiation and its relation to schooling, the role of poverty
and the anti-AIDS success stories in Uganda and Senegal. Programmes designed
exclusively for adolescents were criticised for not being realistic. Programmes
should integrate other groups (adults and women) that are involved in the adolescents'
sexuality.
The idea of modifying the characteristics that cause the sexual behaviours was
judged as promising. For example, increasing the age of first sex might influence
subsequent sexuality and reduce risk factors such as the total number of partners
because early sexual debut is associated with greater life-time number of sexual
partners in many settings worldwide. However, it is difficult to implement because
age at first sex and the age gap between partners depend on factors that are
not easy to alter or may have differential and contradictory effects. Women
with secondary education delay their sexual debut and first marriage while educated
men have their first sexual act earlier than the less educated. In the beginning
of the epidemic, those with some level of schooling were most infected. Later
on, they started using condoms and now are less infected. Schooling does not
reduce risky sexual behaviours; it is sexual education that matters. As for
poverty, models are unable to explain its role in the epidemic due to difficulties
conceptualizing and measuring poverty.
According to Pison, the Senegal success story may be explained by the relatively
high age at first sex, lower prevalence of sexually transmitted diseases, small
migrant population and an early and comprehensive response to the epidemic.
The few success stories in the continent have demonstrated that success is multi-dimensional
and requires the involvement of the community. It is the prerogative of the
community to define what is acceptable to them or not.
Session 10. Modelling and predicting the future
In his paper Impact of infectious disease on future demographic trends N.
Brouard proposed a model of the HIV/AIDS epidemic based on an analogy between
reproduction of the epidemic and the reproduction of the human population. Sustainability
of the virus in the population is related to relatively long periods between
being infected by HIV, the onset of AIDS and death. The epidemic in Africa is
also fuelled by a higher rotation of sexual partners due to a higher competition
among men to find a partner. This imbalance in the sexual market stems from
the combination of high African population growth rates during the early 1970s
and leads to a large age gap between sexual partners. In the discussion, Brouard's
purely demographic explanation of the AIDS epidemic in Africa was challenged
by Vallin's comments that stressed the very cultural nature of the age gap between
partners. Brouard acknowledged that culture has an impact but he maintained
that the demographic factors play a key role in the heterosexual transmission
of HIV. He argued that if there was equilibrium in age between partners, there
would be less competition and partner rotation. Homosexual transmission for
example has nothing to do with demography.
In his paper The AIDS epidemic in Botswana: Optimal treatment and prevention,
G. Feichtinger applied an age-structured epidemiological model to data
from Botswana. This country freely provides antiretroviral medication to all
those who need it. However, the model shows that the medication-only approach
is inefficient. In some cases it decreases the country's welfare even more than
doing nothing at all. Prevention through a change in sexual behaviour appears
to be more efficient. This should include school-based programs and mass media
education programs to fight AIDS.
The paper Forecasting AIDS impact nationally and in sub-populations by R.
Dorrington compared the macro-micro model developed by the Actuarial Society
of South Africa (ASSA) with the Spectrum and EPP combination model, upon which
UNAIDS and WHO estimates are derived, to assess the impact of HIV on mortality
rates. The ASSA model allows one to graph the epidemic at the level of population
sub-groups (for example, by region). It makes for a more realistic model and
provides a better understanding of the general evolution of the epidemic. On
the other hand, it requires more assumptions about parameters for which there
is usually little information.
The two last papers draw on mathematical models and raise concerns about methodological
issues. Shkolnikov recommended avoiding drawing conclusions before verifying
the assumptions of the models.
Final session. Synthesis of the seminar and General discussion
M. Caraël and I. Timæus summarized the papers presented during the seminar using a five- level nested framework. The deepest level represents the interaction between people and disease. This level is nested within the healthcare system, which in turn is nested within the economic, social and cultural context.. The next level is the climate and environment, which is nested in the global context.
Caraël and Timæus remarked that the presentations and discussions
during the seminar focused on determinants of morbidity and mortality and their
reverse influence on population change. Other topics such as fertility, the
mother-child transmission of HIV, the impact of malaria on pregnant women, the
interaction between malnutrition and respiratory infections, diarrheic diseases,
the role of water supply, the privatization of health services received less
attention. There was no presentation of a specific control program. This latter
point stems from the fact that no HIV/AIDS control program has been adequately
evaluated in the continent so far. Indeed, the results of the existing attempts
are disappointing and do not allow for drawing general conclusions. The known
success stories so far, Senegal and Uganda, are exceptions that do not provide
answers to all questions.
The seminar lent itself to the development of a framework that will be useful
for the research and policy-making. There remains the challenge for demographers
and sociologists to operationalise this framework. The seminar also demonstrated
that the medical approach is not sufficient to address infectious diseases and
HIV/AIDS in Africa. Many factors at different levels need to be included into
the explanations to understand for instance why countries that are most economically
developed and most advanced in their transition in Africa are the hardest hit
by the epidemic. One obstacle to overcome is the lack of adequate data, e.g.
nationally representative data on adult mortality. It would be interesting for
the time being to use demographic and health surveys (DHS) data to look at other
factors like health facility attendance. There are also efforts among demographers
and anthropologists to link qualitative and quantitative data in order to increase
the quality of data.
This report was based on a summary report written by Macoumba Thiam.
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