with the aging of the population worldwide , dementia is a real public health priority . in 2000 , the estimated number of dementia cases was 25.5 million people , representing 0.4% of the worldwide population .
nearly two thirds of all people with dementia lived in low- and middle - income countries .
the other most important risk factors are low level of education , heredity , low early - life economic conditions , smoking , alcohol , weak social network , hypertension , cardiovascular diseases , stroke , epilepsy , diabetes , anemia , parkinson 's disease , and head trauma .
although several population - based studies were conducted in developed countries to better understand the epidemiology of this new epidemic , only a few studies have been done in africa . in senegal ,
the estimated number of elderly aged 65 years was 421,305 in 2008 and 420,795 in 2009 .
considering the economic cost of dementia care , senegal is not able to afford such cost .
it is important to have reliable information on the prevalence of dementia to plan for more accurate provision of social and medical services for the elderly population .
studies on dementia in the senegalese elderly population are rare [ 20 , 21 ] .
thus , a study was conducted in senegal to determine the epidemiology of dementia in an elderly population utilizing a primary health care service for retirees in dakar , senegal .
the aim of the present study was to identify risk factors associated with dementia in this population of retirees utilizing the social and medical center ( smc ) of ipres ( institution de prevoyance retraite du senegal ) , dakar , senegal .
this is a health center for the retired senegalese elderly population affiliated to ipres ensuring medical and social services . as a primary care center with diverse health personnel ,
the study population was composed of senegalese elderly patients aged 65 years who came to the smc of ipres for health problems .
those patients who were either < 65 years old or were not able to fulfill the interview ( due to aphasia , delirium , coma , extreme visual and auditory impairment , or cancer at terminal phase ) were excluded .
507 elderly patients aged 65 years  or their relatives  who consulted a doctor for a medical problem at the smc of ipres were first assessed with a screening interview questionnaire .
those who were cognitively impaired , with a sex - matched sample , underwent a clinical exam with neuropsychological testing .
this study was the first step of a research on the validation of a screening tool to screen for dementia in a senegalese elderly population called  the test of senegal .
two screening instruments were used : the interview questionnaire called  aging in senegal and the clinical assessment instrument . the screening interview questionnaire 
aging in senegal contained the following : sociodemographic variables ( age , sex , marital status , education ) , medical history [ vascular diseases ( hypertension , heart diseases , vascular peripheral disease , stroke , diabetes ) , respiratory diseases , arthritis , cancer / benign tumor , parkinson 's disease , epilepsy , genitourinary disease , cataract , glaucoma , hearing impairment , digestive disease ( gastritis , constipation ) , anemia , thyroid disease , head trauma , bone fracture ] , familial history of memory impairment , lifestyle ( smoking , alcohol consumption , walking ) , social network ( social ties with spouse , children , brothers / sisters , friends ; frequency of weekly contact with children , brothers / sisters , friends ; members of community association , member of religious association ) , the patient 's functional autonomy , and the neuropsychological tests with the abbreviated mental test   and the test of senegal .
the clinical assessment instrument had four components : ( 1 ) a historical review of the patient 's cognitive function , i.e. , the onset and progression of any reported symptoms of cognitive impairment ; ( 2 ) a review of the patient 's medical , surgical , and familial history , exposure to toxic products and medications ; ( 3 ) a review of the patient 's functional autonomy , and ( 4 ) a review of the patient 's clinical exam and neuropsychological testing with the mini - mental state examination ( mmse ) .
each patient underwent a screening interview with the questionnaire  aging in senegal by four medical students at the smc who were trained for this issue .
it aimed to collect data related to sociodemographics , lifestyle , past medical history , and social network and to screen for neuropsychological performance with the abbreviated mental test .
after the interview , each patient who had a score of 5 on the abbreviated mental test   was referred for clinical assessment to the principal investigator ( k.t . ) . at the same time , a sex - matched normal subject was also referred for clinical assessment . the clinical assessment consisted of a complete physical exam followed by a neuropsychological testing with the mmse .
if a patient was suspected to have depression , the ces - d scale was administered to him / her to confirm the diagnosis .
all clinical assessments were made without knowledge of the screening status of the patient . at the end of the consultation
, the team members met in a room to confirm the diagnosis of the patient . on the basis of the examination ,
appropriate laboratory exams and computerized tomography of the head were ordered and treatment of associated medical conditions proposed .
sociodemographic variables [ age in 4 categories ( 6569 , 7074 , 7579 , and 80 years ) , sex , marital status , education ] were collected with the medical history and familial history of cognitive impairment .
lifestyle was divided into smoking habit ( yes , no ) , alcohol consumption ( yes , no ) , and walking ( yes , no ) . for the social network , we computed two indexes : diversities of social ties ( score 04 ) and frequency of weekly contact with relatives ( score 06 ) . diversity of social ties
was computed by summing  having a spouse or husband , children , brothers / sisters , and friends and categorized into 3 levels : 02 ties , 3 ties , and 4 ties .
frequency of weekly contact with relatives was obtained by summing the frequency of weekly contact with children , brothers / sisters , and friends and categorized into 4 levels : 03 weekly contacts , 4 weekly contacts , 5 weekly contacts , and 6 weekly contacts .
the medical conditions related to medical variables were dichotomized into  yes or no. dementia was defined according to the dsm - iv - r criteria [ 27 , 28 ] .
this study was approved by the ethical committee of the senegalese ministry of health and university of montreal , que . ,
this is a health center for the retired senegalese elderly population affiliated to ipres ensuring medical and social services . as a primary care center with diverse health personnel ,
the study population was composed of senegalese elderly patients aged 65 years who came to the smc of ipres for health problems .
those patients who were either < 65 years old or were not able to fulfill the interview ( due to aphasia , delirium , coma , extreme visual and auditory impairment , or cancer at terminal phase ) were excluded .
507 elderly patients aged 65 years  or their relatives  who consulted a doctor for a medical problem at the smc of ipres were first assessed with a screening interview questionnaire .
those who were cognitively impaired , with a sex - matched sample , underwent a clinical exam with neuropsychological testing .
this study was the first step of a research on the validation of a screening tool to screen for dementia in a senegalese elderly population called  the test of senegal .
two screening instruments were used : the interview questionnaire called  aging in senegal and the clinical assessment instrument . the screening interview questionnaire 
aging in senegal contained the following : sociodemographic variables ( age , sex , marital status , education ) , medical history [ vascular diseases ( hypertension , heart diseases , vascular peripheral disease , stroke , diabetes ) , respiratory diseases , arthritis , cancer / benign tumor , parkinson 's disease , epilepsy , genitourinary disease , cataract , glaucoma , hearing impairment , digestive disease ( gastritis , constipation ) , anemia , thyroid disease , head trauma , bone fracture ] , familial history of memory impairment , lifestyle ( smoking , alcohol consumption , walking ) , social network ( social ties with spouse , children , brothers / sisters , friends ; frequency of weekly contact with children , brothers / sisters , friends ; members of community association , member of religious association ) , the patient 's functional autonomy , and the neuropsychological tests with the abbreviated mental test   and the test of senegal .
the clinical assessment instrument had four components : ( 1 ) a historical review of the patient 's cognitive function , i.e. , the onset and progression of any reported symptoms of cognitive impairment ; ( 2 ) a review of the patient 's medical , surgical , and familial history , exposure to toxic products and medications ; ( 3 ) a review of the patient 's functional autonomy , and ( 4 ) a review of the patient 's clinical exam and neuropsychological testing with the mini - mental state examination ( mmse ) .
each patient underwent a screening interview with the questionnaire  aging in senegal by four medical students at the smc who were trained for this issue .
it aimed to collect data related to sociodemographics , lifestyle , past medical history , and social network and to screen for neuropsychological performance with the abbreviated mental test .
after the interview , each patient who had a score of 5 on the abbreviated mental test   was referred for clinical assessment to the principal investigator ( k.t . ) . at the same time , a sex - matched normal subject was also referred for clinical assessment . the clinical assessment consisted of a complete physical exam followed by a neuropsychological testing with the mmse .
if a patient was suspected to have depression , the ces - d scale was administered to him / her to confirm the diagnosis .
all clinical assessments were made without knowledge of the screening status of the patient . at the end of the consultation , the team members met in a room to confirm the diagnosis of the patient .
on the basis of the examination , patients with dementia were followed by the principal investigator ( k.t . ) .
appropriate laboratory exams and computerized tomography of the head were ordered and treatment of associated medical conditions proposed .
sociodemographic variables [ age in 4 categories ( 6569 , 7074 , 7579 , and 80 years ) , sex , marital status , education ] were collected with the medical history and familial history of cognitive impairment .
lifestyle was divided into smoking habit ( yes , no ) , alcohol consumption ( yes , no ) , and walking ( yes , no ) . for the social network , we computed two indexes : diversities of social ties ( score 04 ) and frequency of weekly contact with relatives ( score 06 ) . diversity of social ties
was computed by summing  having a spouse or husband , children , brothers / sisters , and friends and categorized into 3 levels : 02 ties , 3 ties , and 4 ties .
frequency of weekly contact with relatives was obtained by summing the frequency of weekly contact with children , brothers / sisters , and friends and categorized into 4 levels : 03 weekly contacts , 4 weekly contacts , 5 weekly contacts , and 6 weekly contacts .
the medical conditions related to medical variables were dichotomized into  yes or no. dementia was defined according to the dsm - iv - r criteria [ 27 , 28 ] .
this study was approved by the ethical committee of the senegalese ministry of health and university of montreal , que . ,
univariate , bivariate , and multivariate stepwise logistic regression analyses were computed . the odd ratios of the different risk factors were computed with a 95% ci .
forty - five patients ( 8.87% ; 95% ci 7.6110.13 ) had dementia . the whole population with a mean age of 72.4 years ( 5.2 ) was mostly male , married , and illiterate .
the elderly population had a high diversity of ties and frequency of contact with relatives and friends ( table 1 ) .
hypertension ( 58.6% ) , arthritis ( 49.5% ) , gastrointestinal diseases ( 24.1% ) , respiratory diseases ( 14.7% ) , and cataract ( 14.4% ) were the main health conditions reported in the past medical history ( table 2 ) . in the bivariate analysis , age ( p < 0.045 ) , education ( p < 0.02 ) , diversity of ties with relatives ( p < 0.001 ) , frequency of contact with relatives ( p < 0.0001 ) , stroke ( p
< 0.002 ) , epilepsy ( p < 0.002 ) , and family history of dementia ( p <
0.0001 ) were associated with dementia . in the multivariate model , advanced age ( 80 years ; or 4.26 ; 95% ci 1.3613.3 ) , illiteracy ( or 2.76 ; 95% ci 1.236.20 ) , epilepsy ( or 11.72 ; 95% ci 2.1065.23 ) , and family history of dementia ( or 7.56 ; 95% ci 3.4216.76 ) were independently associated with dementia ( table 3 ) .
in our study , prevalence of dementia was 8.87% with advanced age , illiteracy , epilepsy , and family history of dementia as independent risk factors .
these risk factors were either self - reported by the patient or informant - reported .
the role of age as a risk factor for dementia has been highlighted in several studies .
in fact , the prevalence of dementia is increasing importantly with age as observed in a clinical setting and during population studies .
thus , the result we observed confirms the role of ageing ( especially advanced age ) in the occurrence of dementia as described elsewhere in europe [ 3 , 29 , 30 , 31 ] , america [ 32 , 33 , 34 ] , asia [ 35 , 36 , 37 ] , and africa [ 21 , 38 , 39 , 40 , 41 ] .
illiteracy was frequent ( 57% ) and was associated with dementia in our elderly population .
this result confirms the role of illiteracy as a risk factor for dementia in an elderly population as already seen in studies realized worldwide [ 42 , 43 , 44 , 45 , 46 ] .
epilepsy in the elderly is frequent , with an estimated prevalence of 1% after 60 years of age   and an incidence increasing with age . in our study population , history of epilepsy
this finding has been observed in several studies conducted worldwide , enhancing the association between a history of epilepsy and dementia in an elderly population [ 13 , 49 , 50 , 51 , 52 ] .
this association could be related to the disease itself , its cause or risk factor , but also to the treatment prescribed , especially in our country , where most of the epileptic patients are on a first - generation anti - epileptic regimen , which is harmful for cognition .
familial history of dementia , which was observed in 9.1% of our study population , has been associated with the occurrence of dementia .
in fact , studies in australia , africa [ 55 , 56 ] , europe [ 57 , 58 ] , and the usa   have demonstrated that familial history of dementia is a main risk factor for dementia in an elderly population .
also , apoe 4 has been associated with alzheimer 's disease in the developed world [ 59 , 60 ] . however , this association is absent in an african study .
genetic mutations are also observed in demented persons at chromosome 12   and chromosomes 6 , 9 , 10 , 12 , 19 , and 21 [ 63 , 64 ] .
limitations of the study include the underestimation of the prevalence because all the demented patients were not recruited during the study period .
medical illnesses were based upon self - report or informant report rather than on direct examination .
moreover , memory bias could underestimate risk factors and , thus , their role in the occurrence of dementia .
also , this study is a prevalence study , not an incidence study , characterized by temporality of the association between risk factors and dementia .
however , it highlights and confirms the role of these risk factors on dementia occurrence in an elderly population .
this study has shown that illiteracy , epilepsy , and familial history of dementia were associated with dementia in this study population .
additionally , it confirms the role of these risk factors in the occurrence of dementia in an elderly population as described elsewhere .
as the senegalese population is aging , it is necessary to take dementia into consideration in the social , political , and medical practice and to sensitize political leaders , the health personnel , and the population for the prevention of this disease .
 backgroundwith the aging of the population , dementia is increasing worldwide . 
 the objective of this study was to identify risk factors for dementia in an elderly population utilizing a primary health care service in dakar , senegal.methodsthrough a cross - sectional study conducted from march 2004 to december 31 , 2005 , 507 elderly patients aged 65 years who came to the social and medical center of ipres , dakar , senegal , were first screened with the screening interview questionnaire  aging in senegal. those who were cognitively impaired underwent a clinical examination to detect dementia . 
 univariate , bivariate , and multivariate logistic regression analyses were done.resultsthe whole population had a mean age of 72.4 years ( 5.2 ) and was mostly male , married , and non - educated . 
 hypertension , arthritis , and gastrointestinal diseases were the main health conditions reported in the past medical history . 
 smoking was important while alcohol consumption was rare . 
 social network was high . 
 forty - five patients ( 8.87% ) had dementia . in the multivariate model , only advanced age , education , epilepsy , and family history of dementia 
 were independently associated with dementia.conclusionthe risk factors identified are also found in developed countries confirming their role in dementia . 
 it is important to take dementia into consideration in senegal and to sensitize the community for prevention . 
Introduction
Methods
Study Design
The Screening Instruments
Interview
Clinical Assessment
Variables of Studies
Ethical Consideration
Statistical Analysis
Results
Discussion
Conclusion
Disclosure Statement