Socio-demographic and reproductive determinants of cervical neoplasia in seven sub-Sahara African countries.
BACKGROUND
Since most human papilloma virus (HPV) infections regress without any intervention, HPV is a necessary but may not be a solely sufficient cause of cervical intraepithelial neoplasia (CIN) and cervical cancer. Hence, the influence of cofactors on progression from cervical HPV infection to high-grade CIN and invasive cervical cancer has been a subject of intensive research.


OBJECTIVE
We assessed the effect of socio-demographic and sexual reproductive factors on the prevalence of invasive cervical cancer and CIN diagnosed in cross-sectional cervical cancer screening projects carried out in seven sites of different sub-Saharan countries.


METHODS
Between January 2000 and August 2007, healthy women aged 25-59 who participated in the screening projects were interviewed for socio-demographic, reproductive, and behavioral characteristics, investigated for disease confirmation with colposcopy, and had biopsies directed from colposcopically abnormal areas by trained local physicians. Odds ratios (ORs) and their 95% confidence intervals (CIs) from logistic regression analyses were used to assess the effect of women characteristics on CIN 1, CIN 2-3, CIN 3, and invasive cancer outcome measures.


RESULTS
Among 47,361 women screened and investigated for disease confirmation, CIN 1 was diagnosed in 1,069 (2.3%), CIN 2 in 517 (1.1%), CIN 3 in 175 (0.5%), and invasive cancer in 485 (1.0%). The site-specific prevalence of CIN 2-3 lesions ranged from 0.3 to 5.1% and from 0.2 to 1.9% for invasive cancers. Risk factors for CIN 2-3 were being widowed or separated versus currently married (OR 1.3, 95% CI 1.0-1.7 a); and having had at least four pregnancies versus zero or one pregnancy (OR at least 1.4-fold, 95% CI 1.1-1.8). Risk factors for invasive cancer were being widowed or separated versus currently married (OR 2.0, 95% CI 1.3-3.1); and having had at least three pregnancies versus zero or one pregnancy (OR at least 3.0-fold, 95% CI 2.1-4.2). Additionally, cervical cancer risk increased with increasing age, age at menarche, and age at marriage, while the risk decreased with increasing level of education and in those with some form of employment compared to housewives.


CONCLUSIONS
The exposure of the exocervix and/or the increased levels of estrogen and progesterone for more prolonged periods during pregnancy in multiparous women and the vulnerability of widowed/separated women in society might result in increased risk of cervical neoplasia more so among women exposed to HPV infection. High parity probably explains the persistently high rates of cervical cancer in sub-Saharan Africa.
Screening Group, International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372, Lyon Cedex 08, France. MuwongeR@iarc.fr.
Richard
R
Muwonge
Prevention and Implementation Group, International Agency for Research on Cancer, Lyon, France.
Louise
L
Ngo Mbus
Ocean Road Cancer Institute, Dar es Salaam, United Republic of Tanzania.
Twalib
T
Ngoma
Département de Carcinologie CHU, Université Marien Ngouabi, Brazzaville, Congo.
Charles
C
Gombe Mbalawa
Département de Gynécologie-Obstétrique, Hôpital Gabriel Touré, Bamako, Mali.
Amadou
A
Dolo
Médica Especialista Ginecologia Obstetricia, Clinica da Rainha Ginga, Luanda, Angola.
Miraldina
M
da Ganda Manuel
Faculté des Sciences de la Santé, Université de Niamey, Niamey, Niger.
Hassan
H
Nouhou
Département de Gynécologie-Obstétrique, Centre Hospitalier National Yalgado Ouédraogo, Ouagadougou, Burkina Faso.
Marius
M
Nacoulma
Ocean Road Cancer Institute, Dar es Salaam, United Republic of Tanzania.
Julius
J
Mwaiselage
Centre National d'Anatomie Pathologique, CHU Donka, Conakry, Guinea.
Moussa
M
Koulibaly
Hôpital Gabriel Touré, Bamako, Mali.
Siné
S
Bayo
Département de Carcinologie CHU, Université Marien Ngouabi, Brazzaville, Congo.
Judith
J
Nsonde Malanda
Prevention and Implementation Group, International Agency for Research on Cancer, Lyon, France.
Hugo
H
De Vuyst
Prevention and Implementation Group, International Agency for Research on Cancer, Lyon, France.
Rolando
R
Herrero
Screening Group, International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372, Lyon Cedex 08, France.
Rengaswamy
R
Sankaranarayanan
Service de Gynécologie/Obstétrique, CHU Donka, Conakry, Guinea.
Namory
N
Keita
D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D003430:Cross-Sectional Studies; D018450:Disease Progression; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008875:Middle Aged; D027383:Papillomaviridae / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000453:epidemiology / Q000473:pathology / Q000821:virology; D010298:Parity; D011247:Pregnancy; D015995:Prevalence; D012307:Risk Factors; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D002578:Uterine Cervical Dysplasia / Q000453:epidemiology* / Q000473:pathology / Q000821:virology
Cervical intraepithelial neoplasia; Invasive cervical cancer; Risk factors; Sub-Saharan Africa