General Population Cohort (GPC)
The GPC facilitates population-based research on diseases of public health importance in Uganda and the wider region, and vital demographic data on changing patterns of ill health in sub-Saharan Africa.
About the General Population Cohort (GPC)
The GPC is the source of rich longitudinal population and clinic data since 1989.
These data, as well as other demographic, epidemiological and genomic data from individual external projects, are extensively linked and shareable.
These provide an important resource for future studies, and the Unit is actively increasing their access.
Similarly, we have long-term blood samples for every survey round since 1989, as well as samples from other projects.
The samples are available for answering research questions for both Unit and external scientists – more than 40 papers have been published in the quinquennium, based on analyses of historical serum samples.
These stored samples also make the GPC particularly attractive for future field research because they provide the ability to compare data historically
Platform
The GPC provides a solid platform for population-based research, which has been crucial in improving our understanding of HIV. More recently, this dynamic structure proved critical in studies on community transmission and impact of SARS-COV2 (COVID-19). Thus, the GPC is not only a source of rich longitudinal data to do your data, but also a resource to embed numerous short-term externally funded studies. It supports all our research themes.
Cohort data
The General Population Cohort (GPC) was set up in 1989 to examine trends in HIV prevalence and incidence, and their determinants in rural south-western Uganda. Recently, the research questions have included the epidemiology and genetics of communicable and non-communicable diseases (NCDs) to address the limited data on the burden and risk factors for NCDs in sub-Saharan Africa.
The cohort comprises all residents (52% aged ≥13years, men and women in equal proportions) within one-half of a rural sub-county, residing in scattered houses, and largely farmers of three major ethnic groups. Data collected through annual surveys include; mapping for spatial analysis and participant location; census for individual socio-demographic and household socioeconomic status assessment; and a medical survey for health, lifestyle and biophysical and blood measurements to ascertain disease outcomes and risk factors for selected participants. This cohort offers a rich platform to investigate the interplay between communicable diseases and NCDs. There is robust infrastructure for data management, sample processing and storage, and diverse expertise in epidemiology, social and basic sciences.
Field Research
Field research constitutes the major part of our research in the GPC and includes census (house-to-house demographic surveillance) and survey activities. We have conducted HIV sero-surveys since 1989 to determine the prevalence and incidence of HIV. In recent years we have collected data on hepatitis B and C, NCDs, SARS-COV2 and population genetic data. From the census, we have data births and deaths, including verbal autopsy.
Census is currently conducted through ‘Field Research Hubs’ periodically set up at central locations within the 25 research villages. Their proximity in the communities has boosted participation in surveys and continues to be a cost effective means of attaining research targets.
Description of the Kyamulibwa General Population Cohort Census and Medical surveys
A series of activities are conducted within the GPC platform at every medical survey round. Broadly, these include:
i) Community mobilisation and mapping of households
The community mobilisation activity focuses on engaging with participants at both community and individual levels. The GPC setting covers 26 adjacent villages which are defined by Uganda’s subnational administrative boundaries, varying in size from 300 to 1500 residents. One pilot village enables pretesting of study tools and procedures. Local leaders (including members of the Local Government councils and Community Advisory Board) from these villages are sensitised on study plans and their permission and support is sought before holding community meetings. Each household which is mapped is assigned a unique identification number.
ii) Census
Every year, the Census assesses each household’s socioeconomic status, and the socio-demographic characteristics of the individuals within the household. Unique identification (ID) numbers were assigned to residents the first time they were surveyed and the same ID maintained over time in both the Census and Medical surveys. At every Census, newborns and new area residents are also assigned unique identification numbers. A census questionnaire is administered to a household head or an adult representative. Overall, over 96% of households approached for census consent and participate.
iii) Medical surveys
Based on the Census, eligible residents are invited to attend the Medical survey at a temporary village medical hub. The hubs are sequentially set up at a central location within each of the 26 villages. Eligible residents are defined by whether an individual spent or is planning to spend at least 3 months in a household within the study area. For each individual, data on health history, behaviour, and lifestyle are collected using a standard questionnaire while maintaining the same participant identification number used in the Census. Blood samples are also obtained and biophysical measurements taken in the same interview session. The questionnaire administered at each Medical survey round focuses on a particular scientific theme, and rounds are conducted every two years.
A robust infrastructure is in place for sample processing and storage, and data management. A clinic located at the field station provides general health care to all study participants who present with acute medical conditions (malaria and acute respiratory tract infections among others) and chronic diseases such as HIV, hepatitis B and C, hypertension, diabetes and dyslipidaemia identified during medical surveys.
Start and End dates of both GPC Census and Medical Survey
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CENSUS |
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MEDICAL SURVEY |
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Round |
Start Date |
End Date |
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Round |
Start Date |
End Date |
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R1CENS |
01 JAN 1989 |
31 OCT 1990 |
R1AMED |
06 DEC 1989 |
31 AUG 1990 |
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R2CENS |
07 NOV 1990 |
24 JUL 1991 |
R2AMED |
28 NOV 1990 |
26 SEP 1991 |
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R3CENS |
21 NOV 1991 |
09 SEP 1992 |
R3AMED |
09 DEC 1991 |
02 NOV 1992 |
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R4CENS |
16 NOV 1992 |
21 SEP 1992 |
R4AMED |
09 DEC 1992 |
29 OCT 1993 |
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R5CENS |
15 NOV 1993 |
29 AUG 1994 |
R5AMED |
08 DEC 1993 |
15 OCT 1994 |
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R6CENS |
16 NOV 1994 |
13 SEP 1995 |
R6AMED |
06 DEC 1994 |
21 OCT 1995 |
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R7CENS |
24 NOV 1995 |
10 SEP 1996 |
R7AMED |
07 DEC 1995 |
26 OCT 1996 |
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R8CENS |
12 NOV 1996 |
06 SEP 1997 |
R8AMED |
10 DEC 1996 |
04 NOV 1997 |
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R9CENS |
18 NOV 1997 |
10 SEP 1998 |
R9AMED |
05 DEC 1997 |
19 NOV 1998 |
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R10CEN |
05 NOV 1998 |
23 AUG 1999 |
R10AMED |
02 DEC 1998 |
20 NOV 1999 |
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R11CENS |
04 NOV 1999 |
25 AUG 2000 |
R11AMED |
09 DEC 1999 |
07 NOV 2000 |
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R12CENS |
06 NOV 2000 |
03 SEP 2001 |
R12AMED |
28 NOV 2000 |
21 OCT 2001 |
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R13CENS |
19 NOV 2001 |
21 AUG 2002 |
R13AMED |
07 JAN 2002 |
13 OCT 2002 |
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R14CENS |
06 NOV 2002 |
22 AUG 2003 |
R14AMED |
11 DEC 2002 |
01 NOV 2003 |
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R15CENS |
04 NOV 2003 |
25 AUG 2004 |
R15AMED |
10 DEC 2003 |
26 OCT 2004 |
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R16CENS |
09 NOV 2004 |
01 SEP 2005 |
R16AMED |
08 DEC 2004 |
28 OCT 2005 |
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R17CENS |
14 NOV 2005 |
07 SEP 2006 |
R17AMED |
16 DEC 2005 |
08 NOV 2006 |
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R18CENS |
27 OCT 2006 |
25 SEP 2007 |
R18AMED |
14 DEC 2006 |
23 OCT 2007 |
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R19CENS |
06 NOV 2007 |
03 NOV 2008 |
R19AMED |
03 DEC 2007 |
15 OCT 2008 |
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R20CENS |
11 NOV 2008 |
02 SEP 2009 |
R20AMED |
11 DEC 2008 |
29 OCT 2009 |
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R21CENS |
18 NOV 2009 |
17 SEP 2010 |
R21AMED |
14 DEC 2009 |
27 OCT 2010 |
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R22CENS |
11 NOV 2010 |
07 OCT 2011 |
R22AMED |
07 JAN 2011 |
29 NOV 2011 |
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R23CENS |
23 JAN 2012 |
14 DEC 2012 |
R23AMED |
08 FEB 2012 |
12 NOV 2013 |
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R24CENS |
22 JAN 2013 |
04 DEC 2013 |
R24AMED |
16 JAN 2014 |
13 NOV 2015 |
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R25CENS |
14 JAN 2014 |
17 DEC 2014 |
R25CMED |
02 MAR 2016 |
07 AUG 2018 |
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R26CENS |
12 JAN 2014 |
11 NOV 2015 |
R26AMED |
25 JUN 2019 |
13 JUL 2021 |
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R27CENS |
03 JAN 2016 |
04 DEC 2017 |
R27AMED |
JAN 2022 |
FEB 2024 |
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R28CENS |
03 AUG 2017 |
15 NOV 2018 |
R28AMED |
AT INCEPTION |
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R29CENS |
11 JUN 2019 |
07 JUL 2021 |
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R30CENS |
DEC 2021 |
OCT 2023 |
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R31CENS |
AT INCEPTION |
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GPC Brochure