depression is associated with morbidity as well as disability among the elderly ( cole and dendukuri , 2003 ) .
they constitute a major public health problem worldwide and their prevalence rates range between 10 and 55% ( sherina et al . , 2004 ; chi et al . , 2005
; tsai et al . , 2005 ; khattri and nepal , 2006 ; kaneko et al . , 2007 ) .
the long - term prognosis of geriatric depression is bleak with incomplete recovery ( jhingan et al . , 2001 ) and higher relapse rates ( mitchell and subramaniam , 2005 ) . along with the physiological and psychological changes associated with aging
, changes in the associated risk factors also modify the prevalence and prognosis of geriatric depression ( van't veer - tazelaar et al . , 2008 ) .
medical co - morbidity ( jongenelis et al . , 2004 ) and cognitive impairment ( steffens and potter , 2008 ) have a complex bidirectional relationship with geriatric depression .
the low positive predictive value ( arthur et al . , 1999 ) as well as doubtful external validity of screening instruments ( krner et al . , 2007 ) may yield many false positive cases and may inflate the prevalence rates of geriatric depression in community settings .
concerns regarding the different cut - off values used to diagnose depression across various settings also exist ( mcgivney et al . , 1994 ;
many studies have not employed structured assessment of depression , cognitive function and disability ( osborn et al . , 2003 ; sherina et al .
, 2004 ; chi et al . , 2005 ; tsai et al . , 2005 ; khattri and nepal , 2006 ; kaneko et al . , 2007 ) .
the only available indian study employing the geriatric depression scale ( gds ) , a screening tool , in a small sample of elderly has reported prevalence of up to 45.9% ( jain and aras , 2007 ) .
another larger indian study evaluating the hindi version of the gds studied only the depressive symptoms and not the depressive disorders ( ganguli et al . , 1999 ) .
we aimed to study the nature , prevalence and factors associated with geriatric depression in a rural south indian community with an adequate sample size and with detailed as well as structured methods of assessment .
we employed a cross - sectional study to examine the nature and prevalence of geriatric depression in a rural community .
the methodology employed in this study has been reported elsewhere ( jacob et al . , 2007a ) and is only briefly mentioned here .
it is spread over 127.4 square kilometers with 85 villages housing a total population of 110,000 .
the department of community health , christian medical college , vellore has been running a community health program in this block for the past five decades .
it has developed a four - tier monitoring and computerized surveillance system of the residents of kaniyambadi block , which is updated monthly .
the community health workers , who live within the various village communities , provide the detailed statistics ( joseph et al . , 1991 ) .
participants were identified using a computerized list and a door - to - door survey .
we invited all elderly people over 65 years of age to participate in this study .
the following instruments were employed to assess the participants : ( i ) geriatric mental state ( gms ; copeland et al . , 1986 ) , ( ii ) community screening instrument for dementia ( csid ; hall et al . , 1993 ; 2000 )
, ( iii ) world health organization disability assessment scale ii ( whodas ii ; world health organization , 2001 ) , ( iv ) modified cerad 10-word list learning task ( ganguli et al . , 1996 ) , ( v ) history and aetiology schedule dementia diagnosis and subtype ( has - dds ; copeland et al . , 2002 ) ,
( vi ) neuropsychiatric inventory , and ( vii ) a structured proforma to assess socio - demographic characteristics , medical history and anthropometrics .
whodas ii ( world health organization , 2001 ) have been employed in earlier studies .
the training of research staff , data collection and quality control procedures were in accordance with 10/66 norms for population - based studies ( prince et al . ,
we initially analyzed the socio - demographic data , medical history , psychopathology , cognitive profile and the disability status using descriptive statistics .
we derived the psychiatric diagnoses based on the computerized algorithms developed by the 10/66 dementia research group ( prince et al . , 2003 ) .
we converted the continuous exposure variables to categorical measures by splitting them into two categories using their median values ( ragin , 1994 ) .
we performed multivariate analysis using determinants , which were significant on univariate analysis , employing conditional logistic regression with the statistical software package spss 16.0 .
the socio - demographic , psychiatric and disability profiles of the participants are shown in table 1 .
the majority of the participants were women , lacking formal education , widowed and from the low - income category .
= rupees ; dsm - iv = diagnostic and statistical manual of mental disorders , 4 edition ; whodas = world health organization disability assessment scale .
socio - demographic and psychosocial profiles of the participants ( n = 1000 ) rs . =
rupees ; dsm - iv = diagnostic and statistical manual of mental disorders , 4 edition ; whodas = world health organization disability assessment scale .
the prevalence of any icd-10 ( world health organization , 1992 ) depressive episode in our sample was 12.7% ( 95% ci 10.6414.76 % ) . among those 127 participants who had geriatric depression ,
32 had a mild depressive episode ( 3.2% ; 95% ci 2.114.29% ) , 76 had a moderate depressive episode ( 7.6% ; 95% ci 5.969.24% ) , and 19 had a severe depressive episode ( 1.9% ; 95% ci 1.052.75% ) .
the prevalence of major depression according to dsm - iv ( american psychiatric association , 1994 ) criteria was 5.2% ( 95% ci 3.826.58 ) .
the prevalence of suicidal ideation within the previous month was 2.1% ( 95% ci 1.212.99 ) .
the prevalence of dementia defined by dsm - iv was 0.8% and by the education - adjusted 1066 criteria was 10.6% .
low income , experiencing hunger within the previous one month , having diabetes , cardiac illnesses , transient ischemic attacks and head injury were correlated with geriatric depression after adjustment for the effects of age , gender , education and the other determinants using conditional logistic regression analysis .
female gender , age , hypertension , cognitive impairment and more disability were not significantly correlated with geriatric depression . 

table 2factors associated with depression in the elderly adjusted odds ratios calculated using conditional logistic regression .
the following variables were included in the conditional logistic regression analysis : age , gender , education , low income , experiencing hunger , living alone , living within five miles from siblings , having more confidants , no regular physical exercise , diabetes , tuberculosis , heart problems , transient ischemic attack , head injury , hearing impairment and smaller mid - arm circumference . walking for at least 500 meters less than six times per week .
factors associated with depression in the elderly   adjusted odds ratios calculated using conditional logistic regression .
the following variables were included in the conditional logistic regression analysis : age , gender , education , low income , experiencing hunger , living alone , living within five miles from siblings , having more confidants , no regular physical exercise , diabetes , tuberculosis , heart problems , transient ischemic attack , head injury , hearing impairment and smaller mid - arm circumference .   walking for at least 500 meters less than six times per week .  
according to the dsm - iv criteria , the following variables were significantly associated with geriatric depression after adjustment for the effects of age , gender , education and the other determinants using conditional logistic regression analysis : experiencing hunger within the previous month ( or 2.55 ; 95% ci 1.245.24 ) ; diabetes ( or 4.15 ; 95% ci 1.4711.73 ) ; transient ischemic attacks ( or 3.23 ; 95% ci 1.317.96 ) ; past head injury ( or 3.69 ; 95% ci 1.429.55 ) ; mid - arm circumference less than 24 cm ( or 4.52 ; 95% ci 1.7211.89 ) ; and more disability ( or 4.36 ; 95% ci 1.949.81 ) .
the significant correlates for recent suicidal ideation , adjusting for age , education and gender using multivariate logistic regression were : being depressed ( or 4.35 ; 95% ci 1.7510.78 ) ; experiencing hunger within the previous one month ( or 2.71 ; 95% ci 1.066.92 ) ; average monthly income of the family less than rs .
the significant correlates for more functional disability charcterized by whodas ii total score more than 25 , adjusting for age , education and gender using multivariate logistic regression were : being demented ( or 2.84 ; 95% ci 1.784.53 ) ; transient ischemic attacks ( or 4.73 ; 95% ci 2.1810.26 ) ; hard of hearing ( or 2.23 ; 95% ci 1.672.97 ) ; age above 71 years ( or 1.97 ; 95% ci 1.522.56 ) ; decreased vision ( or 1.75 ; 95% ci 1.272.40 ) ; female gender ( or 1.62 ; 95% ci 1.192.20 ) ; lack of formal education ( or 1.52 ; 95% ci 1.092.12 ) ; experiencing hunger ( or 1.51 ; 95% ci 1.042.20 ) .
a severe depressive episode was not significantly associated with more functional disability ( or 1.10 ; 95% ci 0.432.81 ) .
this study examined the factors associated with depression among the elderly in a rural south indian community .
its strengths include a low refusal rate , adequate sample size and ascertaining depression with a standardized diagnostic interview .
the possibility of selection bias was avoided by recruiting all consecutive elderly people and by the low refusal rate .
we attempted to minimize the recall bias by collaborating with local community health workers and by using a detailed and structured interview .
physical illnesses and poverty were significantly correlated with geriatric depression , as in other studies ( cole and dendukuri , 2003 ; osborn et al .
, 2003 ; sherina et al . , 2004 ; tsai et al . , 2005
; chi et al . , 2005 ; khattri and nepal , 2006 ; jain and aras , 2007 ; kaneko et al . , 2007 ) .
however , female gender , advancing age and cognitive impairment were not associated with geriatric depression .
the depressed individuals in low - income communities rarely subscribe to biomedical causal models and hold more to psychosocial as well as interpersonal explanatory models for depression ( pereira et al . , 2007 ) .
such explanatory models may mitigate perceived stigma ( raguram et al . , 1996 ) .
the meager expectations by families of their elderly relatives may also contribute towards high tolerance of depressive symptoms and functional impairment ( jacob et al .
elderly people report depressive symptoms when they are distressed , when they are ill or are worried about the implication of their symptoms .
stressful life events and inability to cope with psychosocial problems may also lead the elderly to mention such symptoms .
consequently , the difficulty in separating distress from depression becomes a major issue ( heath , 1999 ) . while psychiatrists suggest that brief screening instruments can easily identify people with depression ( kessler et al . , 1999 )
, most general practitioners ( gps ) would argue that many of those identified are distressed ( heath , 1999 ) . the depression seen in the community and which many gps encounter is often viewed as a result of personal and social stress , life style choices or as a product of habitual maladaptive patterns of behavior .
consequently , the general population and primary care physicians often hold psychological and social models for depression ( jacob , 2006 ) . psychiatrists , with their biomedical frameworks , would on the other hand argue for disease models ( kessler et al . , 1999 ) .
the relationship between poverty , social isolation , physical health and mental health is complex ( kuruvilla and jacob , 2007 ) .
however , the cross - sectional and observational nature of this study mandates the need for cohort designs to confirm associations and randomized trials to assess intervention .
k. s. jacob and m. prince designed the study and supervised data collection and analysis .
rajkumar , p. thangadurai and k. s. jacob analyzed the data and wrote the paper .
 background : depression in old age is an important public health problem causing considerable morbidity and disability worldwide . 
 there is a dearth of community studies from india investigating geriatric depression and its associated risk factors . 
 this study aimed to establish the nature , prevalence and factors associated with geriatric depression in a rural south indian community.methods : we recruited 1000 participants aged over 65 years from kaniyambadi block , vellore , india . 
 we assessed their socio - demographic profile , psychiatric morbidity , cognitive functioning , anthropometrics and disability status using the following structured assessment tools : geriatric mental state , community screening instrument for dementia , modified cerad 10 word list learning task , history and aetiology schedule dementia diagnosis and subtype , who disability assessment scale ii , and neuropsychiatric inventory . 
 we adopted a case control framework to study the factors associated with geriatric depression.results : prevalence of geriatric depression ( icd-10 ) within the previous one month was 12.7% ( 95% ci 10.6414.76% ) . 
 low income ( or 1.78 ; 95% ci 1.082.91 ) , experiencing hunger ( or 2.58 ; 95% ci 1.564.26 ) , history of cardiac illnesses ( or 4.75 ; 95% ci 1.9611.52 ) , transient ischemic attack ( or 2.43 ; 95% ci 1.175.05 ) , past head injury ( or 2.70 ; 95% ci 1.365.36 ) and diabetes ( or 2.33 ; 95% ci 1.154.72 ) increased the risk for geriatric depression after adjusting for other determinants using conditional logistic regression . having more confidants ( or 0.13 ; 95% ci 0.060.26 ) was the significant protective factor . 
 age , female gender , cognitive impairment and disability status were not significantly associated with geriatric depression . 
 dsm - iv diagnosis of major depression was significantly correlated with experiencing hunger , diabetes , transient ischemic attack , past head injury , more disability and less nourishment ; having more friends was protective.conclusions : geriatric depression is prevalent in rural south india . 
 poverty and physical ill health are risk factors for depression among elderly while good social support is protective . 
Introduction
Methods
Results
Discussion
Conflict of interest
Description of authors' roles