in japan , the elderly population has been growing . with the increasing aging of society , the number of homebound elderly is growing . homebound older adults are confined to their homes because of physical , psychiatric , and social limitations . being homebound is associated with a number of conditions , including low basic and instrumental activities of daily living , psychiatric diseases , such as dementia , physical illness , and malnutrition . moreover , several reports have indicated that being homebound is associated with a high mortality rate . the decrease in the number of opportunities to go out may itself be a consequence of poor health . alternatively , the loss of the opportunity to leave the home may lead to both physical and mental disuse . social relationships are known to be one of the core elements of quality of life for seniors . the public long - term care insurance ( ltci ) system was introduced in 2000 to meet the increasing need for elder care in the rapidly aging society of japan . the individuals who need continuous care are classified into one of the care levels according to their mental or physical disabilities , whereas those who need support for daily activities but do not need care are classified as support level 1 or 2 . self - rated health has been reported to be associated with mortality and functional declines . the association between homebound status and self - rated health , however , has not been reported . an epidemiological survey of the homebound elderly in japan would provide useful information in terms of considering intervention and policy making . in the current study we aimed to clarify the incidence of homebound in the elderly in a city in japan . this study was performed in nagoya city , which is located in the central part of japan . nagoya city has a population of 2,261,377 ( april 2010 ) , of whom 21.4 % are 65 years of age or older . this study was developed and organised by nagoya city and was supported by the department of community healthcare & geriatrics of the nagoya university graduate school of medicine . the study was approved by the ethical committee in nagoya university graduate school of medicine on march 26 , 2014 ( # 4233 ) . written informed consent was obtained from all participants . the city office randomly enrolled 5,000 of all of the residents of nagoya city aged 65 and over . a questionnaire was sent at september 1 , 2010 by mail , and 3,444 ( 68.9 % ) subjects returned the survey a by 15 october , 2010 . the investigators obtained the totally anonymous data from the city office . in the present study , the data of 3,053 ( 61.6 % ) subjects for whom complete sets of data were available were employed for statistical analysis . the questionnaire included the following items : age , sex , the status of public ltci certification ( none , support - level , care - level ) , self - rated health ( good , fair , poor , very poor ) , states of living ( single living , with only spouse , with other family members ) , and the frequency of excursions per week ( every day , once in a few day , one a week , rarely ) including day care service usage in ltci . being homebound was defined in the current study as a frequency of excursions per a week that was less than once a week . approximately 54.0 % of the responders went out every day , 31.6 % went out once every few days , 9.0 % went out once in a week , and 5.4 % went out rarely . the frequency of going - out distributed differently in men and women ( p<0.001 ) ( fig . 1 ) . in the current study , being homebound was defied as going out less than once per week . the proportion of the homebound elderly in the elderly population over 65 years - old was 14.4 % in this setting . as the age of the population increase , the proportion of homebound elderly increased ( p<0.001 ) . with respect to the male population 7.3 % of men 6569 years old , 10.5 % of men 7074 years old , 15.7 % of men 7579 years old , 20.7 % of men 80 84 years - old , and 38.4 % of men over 85 years old were homebound . with respect to the female population , 7.5 % of women 6569 years old , 9.3 % of women 7074 years old , 12.7 % of women 7579 years old , 26.2 % of women 8084 years old , and 33.6 % of women over 85 years old were homebound ( table 1 ) . approximately 14.4% of the elderly over 65 years old went out once a week or less . rate of the homebound according to age and sex the  analysis did not identify any significant differences between males and females with respect to the frequency of homebound individuals in each age category . approximately 11.3 % ( 4.8 % for support levels , and 6.5 % for care levels ) of the subjects involved in the study was certified by public ltci . a 11.2% ( 311/2708 ) of the non - certified elderly , 33.8% ( 50/148 ) of the elderly with support levels , and 40.1% ( 79/197 ) of the ones with care levels was homebound . as the level of certification increased ( support levels and care - need levels ) , the proportion of homebound individuals increased significantly in both men and women ( table 2 ) . when stratified by age , more homebound individuals were observed among the non - certified subjects as age increased ( fig . 2 ) .   rate of homebund by the certified levels of public ltci the frequency of being homebound stratified by age and certified levels . as the age increased , the proportion of homebound individuals increased among the non - certified subjects . the status of the living situation ( living alone , with spouse , with other family members , or , other ) was not associated with being homebound ( p=0.355 ) . in men the distribution was not associated with the status of the living situation , while in women the distribution was significantly different according to the status of the living situation ( table 3 ) . rate of the homebopund by the living status self -rated health was significantly worse among the homebound than among the non  homebound . approximately 32.1 % of the non - homebound rated their health as good , 59.8 % as fair , 5.3 % as poor , and 2.8 % as very poor . among the homebound , 12.3 % rated their health as good , 52.8 % as fair , 15.7% as poor , and 19.2 % as very poor ( fig . multiple logistic analysis with sex ( male1 , female=0 ) , age ( 5 year category ) , status of certification of ltci ( non - certified=0 , support level=1 , care level=2 ) showed that age ( odds ratio 1.517 ; 95% confidential interval 1.4021.642 , p<0.001 ) and certification level ( odds ratio 1.746 ; 95% confidential interval 1.4842.054 , p<0.001 ) were positively associated with homebound . in the current survey performed in a city area in japan , approximately 14.4 % of the population over 65 years old was homebound . estimates of how many elderly persons are homebound range from 10.3 % to more than 30.0 % . a rate of 10.6 % was reported by a study in a rural area in japan . several studies in united states and in uk reported that women are more prone to being homebound , and several japanese studies also showed the same trend . however , in the current survey , we did not observe any sex differences among the prevalence of the homebound . the analysis divided by thecertified levels of public ltci and the living status did not show the difference of homebound prevalence between men and women in the current study . lower education and income may be speculated to explain the female dominance in the previous studies ; social and cultural backgrounds should be further studied . ganguli et al . reported that being widowed was a risk for being homebound . in the current survey , may be associated with better health status , cognitive function , and activities of daily livings . ltci provides services according to support levels 1 and 2 and care levels of 15 . people certified as care level require more assistance . in the current survey , the prevalence of the homebound increased according to the increase in the ltci certification levels . our previous study demonstrated that the introduction of services provided by public ltci significantly reduced care - giver burden . among the older subjects , more non - certified subjects tended to be homebound . self - rated health is reportedly associated with decreased survival or function . in the current survey , we observed significantly lower self - rated health in the homebound . nearly 90 % of the homebound rated their health as fair , poor , or very poor . a study found that lower self - rated health was associated with depressive mood . as stated previously , depressive mood is also a risk for homebound.elderly individuals with depression are likely included in the homebound found in the current study . a study reported that being homebound was not necessarily due to an impairment in mobility or iadl . compared to rural areas , urban areas tend to have better transportation systems , which may protect against becoming homebound , but fewer social relationships in the community , which may contribute to becoming homebound . another study from japan reported that feasibility of access in the neighbourhoods was associated with homebound status . the housing environment including public transplantation system and shopping services also differs in rural and urban areas . the current rate of the homebound elderly should be compared with some rural areas . the survey was based on a self - report , which is a major limitation in the current study . depressive mood may be a factor associated with being homebound ; however , in the current study , we did not assess depressive mood , which is another limitation . further , we were only able to analyse 63.4 % of the initial 5,000 subjects who were invited to participate in the survey by mail . we observed that 14.7 % of the population over 65 years old in a city area in japan were homebound . the relatively high rate of homebound status in the elderly population requires increased medical and political attention . authors contributions : hu contributed to the study design , statistical analysis , interpretation of the data , and preparation of the manuscript . my , hn , tm , and mk contributed to the acquisition of the data and interpretation of the data . sponsor s role : this study was partly supported by funding from the japanese ministry of health , welfare and labor ( h24ya003 and h24ub005 - 01 ) .
abstractbeing homebound has been reported to be associated with a number of conditions . in the current study , 
 the incidence of homebound individuals was surveyed in an urban city area in japan . 
 the city office randomly enrolled 5,000 residents of nagoya city aged 65 and over . 
 a questionnaire was sent to their principal caregivers by mail , and 3,444 ( 68.9 % ) subjects returned the survey . 
 the investigators obtained the totally anonymous data from the city office . 
 this study was approved by the ethics committee of nagoya university graduate school of medicine . in the present study , 
 the data of 3,053 ( 61.1 % ) subjects for whom complete sets of data were available were employed for statistical analysis . 
 the questionnaire included the following items : age , sex , the status of public long - term care insurance certification ( none , support - level , care - level ) , self - rated health ( good , fair , poor , very poor ) , states of living ( single living , with only spouse , with other family members ) , and the frequency of outside excursions per a week ( every day , once in a few day , one a week , rarely ) . 
 an individual was defined as being homebound if his or her frequency of outside excursions was less than once per week . 
 he incidence of the homebound elderly in the elderly population over 65 years old was 14.4 % in the current study . 
 the status of certification in public long - term care insurance was associated with being homebound . 
 self - rated health was significantly worse in homebound individuals than in those non 
 homebound . 
 the current survey found 14.4 % of the elderly was home - bound in a large city in japan .