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india is currently undergoing a demographic transition , with a shift to a higher proportion of elderly ( increased from 5.6% in 1961 to 7.4% in 2001).(1 ) increasing numbers of people are at risk of age - related visual impairment as the elderly population increases.(2 ) blindness and hearing impairment contribute heavily to the overall burden of impairment .
more than half of all the impaired persons in india have either visual or hearing impairment.(3 ) even as the elderly are at a higher risk of developing disabilities , it is also possible that the presence of single or multiple disabilities may increase the risk of death among them .
the  at - risk approach , used in maternal and child health care , can be adopted for the care of the elderly as well.(4 ) identification of groups among the elderly , who are at a greater risk of dying , will facilitate targeted interventions , with optimal utilization of the available resources . among them , blindness and hearing impairment could be two possible predictors of mortality .
various researchers in industrialized countries have studied the association of blindness and/or hearing impairment with mortality in the elderly.(517 ) it was felt that it would be useful to study this association in india .
the objective of the present community - based prospective study was to examine the association of blindness and hearing impairment with mortality in a cohort of elderly persons , aged 60 years or more , in a rural area .
the study was conducted in villages that are covered under the intensive field practice area ( ifpa ) of the comprehensive rural health services project ( crhsp ) , ballabgarh , district faridabad , haryana .
it is a collaborative project between the all india institute of medical sciences , new delhi , and the state government of haryana .
health care services are provided by medical officers and their teams of health assistants and health workers , through a network of two primary health centers and twelve sub - centers .
a health management information system ( hmis ) is in place , wherein , every person in these villages is allocated a unique 16-digit number and is under continuous demographic surveillance .
ethical approval for the study was obtained from the ethics committee of the all india institute of medical sciences , new delhi , india .
the relative risks reported in previous similar studies ranged from 1.15 to 2.9.(911 ) the december 2007 , census data of this area had reported a death rate of 4.45% in elderly persons . considering a relative risk of 2.0 , and 4.45% deaths among the non - blind elderly persons , with
a 5% level of significance , and power of 80% , the estimated sample size was 1381 elderly persons .
this sample size was calculated for an exposed : unexposed ratio of 1 : 3 .
the study population consisted of all elderly persons ( age 60 years ) living in the study villages at the time of baseline examination .
the total population of the selected villages was 23979 , including 1465 ( 6.1% ) elderly persons ( crhsp ballabgarh  december 2007 census ) .
of these 1465 persons , 1422 ( 97% ) were recruited and followed up for the outcome measurement , with no loss to follow - up . of the remaining 43 persons ,
17 refused to participate , 16 were excluded from the study , as it was not possible to administer the study tests to them , and 10 could not be contacted despite three visits to their homes .
baseline data collection was carried out from may 2008 to august 2008 , and follow - up data collection was completed in the month of december 2009 .
a questionnaire was administered to all the study participants , to collect information on the sociodemographic details , history of associated morbidities ( hypertension , diabetes mellitus , coronary artery disease , stroke , and any orthopedic impairment ) , data on self - rated health , and feeding and dressing .
it was developed in english , translated into hindi , and then back - translated into english to check for the correctness of the translation .
the history of five of the above - mentioned specific morbidities was elicited by asking the question ,  are you suffering from any of these illnesses , or have you taken treatment for any of them ?  orthopedic impairment was assessed by observation as well .
the vision was recorded at a distance of 6 m separately for each eye ; with distant glasses , if any .
blindness was defined as a visual acuity of less than 6/60 in the better eye , with available correction . for hearing assessment
, all participants were administered the whisper test first , and subsequently examined with the rinne 's test and weber 's test , using a 512 hz tuning fork by the investigator .
the initial calibration and fortnightly appraisals during the period of data collection were done under the supervision of a faculty from the department of the ear , nose , and throat ( ent ) , all india institute of medical sciences , new delhi .
all participants found blind or hearing impaired at the time of baseline examination were referred to ophthalmology and ent clinics at the comprehensive rural health services project ( crhsp ) , ballabgarh hospital for management .
they were asked about any improvement of visual / auditory status during the follow - up period .
data for the outcome variable , that is , all - cause mortality during the follow - up period , were collected from death registers maintained by health workers of the sub - centers covering the respective villages .
accredited social health activists ( ashas ) and anganwadi workers of the respective villages were also contacted to collect data on the deaths that occurred after the last visit of the health worker .
furthermore , the mortality data were cross - checked for deficiencies / discrepancies , if any , with the health management information system ( hmis ) at crhsp , ballabgarh .
the association of the demographic variables and various self - reported morbidities , with mortality , was compared using the chi - square test .
the cox proportional hazard models , both univariate and multivariate , were used to find the hazard of blinding and hearing impairment on mortality .
results of the 1422 participants  58.1% were in the age group of 60 to 69 years . about half ( 51.7% ) of the participants
were female and three - fourth of the participants ( 75.5% ) had had no schooling .
sixty - two ( 4.4% ) participants were dependent on others for dressing and 53 ( 3.9% ) for feeding .
hypertension was reported by 10.7% and diabetes mellitus by 6.9% participants [ table 1 ] .
their own health was reported as fair by 68.3% , poor by 14.9% , good by 13.5% , very poor by 1.8% , and excellent by 1.5% of the participants .
baseline characteristics of the participants there were no out - migrations among participants during the follow - up period .
no participant reported improvement of vision or hearing impairment during the follow - up period .
one hundred out of the 1422 ( 7% ) participants died during the follow - up period .
the follow - up period for participants ranged from a minimum of three days to a maximum of 567 days , with the median follow - up period being 518 days .
out of 134 blind participants , 15 ( 11.2% ) died , as compared to 85 deaths ( 6.6% ) out of 1288 participants with normal vision ( p=0.048 ) .
the percentage of deaths was significantly ( p=0.001 ) higher in participants with hearing impairment ( 13.3% ) , as compared to participants with no hearing impairment ( 5.9% ) .
after adjustment for all the covariates ( age , sex , literacy , hypertension , diabetes mellitus , coronary artery disease , stroke , orthopedic impairment , dressing , feeding , self - rated health ) , neither blindness nor hearing impairment was found to be significantly associated with mortality .
adjustment for only morbidities had no effect on the crude hazard ratios [ table 2 ] .
association of blindness and hearing impairment with mortality on further exploratory analysis by age and sex , hearing impairment was found to be significantly associated with mortality in the age group 70 years with a hazard ratio of 2.13 ( 1.29  3.54 ; 95% ci ) .
hazard ratios for blindness in the age group 60  69 years could not be calculated , as there were no events in that group [ table 3 ] .
in this cohort study , we investigated the association of blindness and hearing impairment with mortality in the elderly age group in a rural area . a few studies conducted across the world
have addressed the same study question , albeit in urban areas.(517 ) in the indian context , as more than two - thirds of the population is residing in rural areas , this is an important consideration .
this corroborates the evidence generated from similar previous studies.(517 ) the male gender appeared to be protected for blindness as compared to the female gender in this univariate analysis . however , no association existed between blindness and mortality , after adjustment was made for sociodemographic factors ( age , sex , and literacy ) .
one of the possible reasons for the differing results could be the different sociodemographic factors for which the adjustments were made.(512 ) in the study by wang et al .
, from australia , adjustments were made for height , weight , body mass index , and home ownership , apart from age and sex,(5 ) and in another study by lee et al . from usa , adjustments were made for age , sex , race , and marital status.(7 ) adjustments only for the selected morbidities , had no effect on the observed association between blindness and mortality .
this was in support of the evidence generated by various similar previous studies.(5681012 ) however , in some studies , the observed association between blindness and mortality was no longer present , at least in some subgroups , once the adjustments were made for the identified confounders.(711 ) this could be due to a difference between various potential confounders adjusted for in the studies , and different methods used for their ascertainment .
hearing impairment remained associated with mortality ; however , the results became insignificant once adjustments were made for the sociodemographic factors , especially age .
this was in agreement with one study conducted in canada by ostbye et al.(15 ) hearing impairment was found to be significantly associated with mortality even after adjustment for all the potential confounders in the age group of 70 years or more .
similar significant associations were reported in the same age group in one previous study in italy.(16 ) it is possible that hearing impairment is a marker of accelerated aging , and hence , is indicative of a greater risk of death in those who are hearing impaired .
, in the united states , significant association was found between hearing impairment and mortality among a group of women belonging to the non - white , non african  american race ( including asians , among others).(14 ) a couple of limitations need to be mentioned .
first , the period of person - years of follow - up in the present study was smaller in comparison to other similar studies , mostly due to the lower duration of follow - up .
second , the method of ascertainment of the comorbid conditions was self - reported by the participants , which could have resulted in some diagnostic gap for the said morbidities . to conclude , the results of the present study showed that elderly persons aged 70 years , residing in the rural area , who suffered from hearing impairment , were at increased risk of mortality , as compared to persons without this impairment .
sociodemographic factors ( age , sex , and literacy ) had a strong confounding effect . however , the presence of various comorbid conditions ( hypertension , diabetes mellitus , coronary artery disease , stroke , and orthopedic impairment ) had no effect on this association .
the presence of hearing impairment in the age group 70 years should be considered as a risk factor for mortality , and more efforts for mortality reduction should be directed toward this  at - risk group through screening . with the increase in the elderly population in india , similar studies with longer follow - up periods
background : studies in developed nations have reported an association of blindness and hearing impairment with mortality in elderly persons.objectives:to study the association of blindness and hearing impairment with mortality in a cohort of elderly persons in rural north india.materials and methods : this community - based prospective study was conducted in eleven randomly selected villages , in ballabgarh block , haryana . a cohort of 1422 participants , of age 60 years and above , was examined at baseline , for their visual and hearing status . 
 data on the sociodemographic factors , various comorbidities , activities of daily living , and self - rated health were recorded . 
 baseline data was collected for the period may 2008 to august 2008 . 
 follow - up data collection for mortality was completed in december 2009 . 
 the median follow - up period was 518 days.results:one hundred out of 1422 elderly ( 7.0% ) participants died during the follow - up period . 
 significant hazard ratios were found after adjustment for various comorbid conditions . on adjustment for sociodemographic factors ( age , sex , and literacy ) , 
 neither blindness nor hearing impairment was found to be significantly associated with mortality . after adjustment for all covariates in the study , hearing impairment ( hazard ratio = 2.13 ; 95% ci , 1.29  3.54 ) was found to be significantly associated with mortality in the age group 70 years.conclusions:this study demonstrated that hearing impairment was an independent risk factor for mortality in people aged 70 years . 
 similar studies with a longer period of follow - up are required in india , to guide public health interventions .