Decomposing socio-economic inequality for routine medical check-ups among older adults in India


 BackgroundRoutine medical check-ups not only reduce the health-care costs over time by detecting potentially life-threatening health conditions at an early stage but also reduces the risk of getting sick and thereby increasing the life span and improving overall health. Therefore, this study examined the prevalence and factors associated with medical check-ups among older adults in India.MethodsThe study utilized data from Building a Knowledge Base on Population Aging in India(BKPAI). The routine medical check-up is the outcome variable of this study. Multivariate analysis has been implemented to fulfil the objectives of the study. Concentration index and decomposition analysis were carried out to examine observed socio-economic inequality in the routine medical check-ups.ResultsNearly one-fourth (23.1%) of the older adults were undergoing the routine medical check-up. Older adults with below five years (OR, 1.31; CI: 1.13-1.51), 6 to 10 years (OR, 1.36; CI: 1.16-1.60), and 11+ years of schooling (OR, 2.02; CI: 1.6-2.54) were significantly more likely to go for routine medical check-ups than illiterate older adults. The concentration Index value of 0.19 depicts the pro-rich inequality in health check-ups among older adults. Furthermore, the results from the decomposition analysis revealed that the wealth quintile of the household contributed nearly 57 percent to the observed socio-economic inequality in the prevalence of routine medical check-up. Education and working status of older adults made a substantial contribution to the inequalities in routine medical check-ups and explained 16.9 percent, and 4.2 percent of the total inequality, respectively.ConclusionsFrom a policy perspective, at first, there is a dire need to spread awareness about the usefulness of routine medical check-ups among older adults. Further, this study reflects the association between education and routine medical check-up, and therefore there is a need to promote literacy at the grass-root level; also, it is recommended to promote health literacy among the older adults. A low level of medical check-up among older adults in rural areas could be reduced by offering free health check-ups regularly. Furthermore, the care of the elderly needs to be prioritized while policy formulation.


Introduction:
Today, the world is gripped with struggles of ageing and age-related issues [1]. Irreversible demographic transition is, by far and large, changing the age structure all around the globe [2].
Initially, what seemed like a developed country problem, is seeping in to even low and middleincome countries, i.e., developing countries [3], [4]. It is presumed that by 2050, 80% of the elderly population would be living in low and middle-income countries [5]. According to WHO (2011), an escalation of 250% among the elderly population can be predicted in low and middleincome countries, while just a 71% increase in the developed countries during the period of 40 years, starting from 2010 to 2050.
India is home to nearly 104 million older adults (age 60+), Census 2011, and it is expected to grow to 173 million by 2026 [6]. The elderly in India mostly suffer from cardio-vascular diseases, circulatory illnesses, and cancer [7]- [9]. Thus, it is imperative to turn our attention to health care practices of the elderly, given the state of the increasing burden of diseases of the growing older adult population. The ageing population comes across as the most vulnerable group and in dire need of health care attention and healthy intervention. Hence, there exists a need to promote certain behavioral practices that ensure healthy ageing, the most important being regular health checkups. Even in general terms, the people who adopt health care strategies can control the onset of various health conditions, which further may result in morbidity or mortality [10].
In recent times, the promotion of health check-ups has proved to be one of the advantageous practices. It was identified that those who underwent regular health check-ups from a pre-elderly stage of life turned out to be healthier in older stages [11]. It was also found that healthy practices, including regular health check-ups, led to early detection of the disease, which in turn paved the way towards hale and hearty older population [12]. Early detection of long-term morbidities also decreases the socio-economic burden on patients and communities [13].
However, older adults have little or almost no awareness and the importance of regular health check-ups in disease detection [14]. India, notably, lags in this aspect of regular health checkups.
Most of the research work done on the Indian elderly population highlights the prevalence of morbidities, comorbidities, or focuses on the health-seeking behavior of older adults [15], [16].
However, none seek to emphasize the behavioral aspect of health check-up. Regular and thorough health check-ups have been established as one of the primary habits that can sustain and ensure a healthier ageing process, yet there is a dearth of literature on the same Existing studies point towards health-seeking behavior; however, the aspect of regular health check-ups remains untouched. Prevention is better than cure -this phrase is particularly important regarding the elderly. Even the people who seem more or less healthy are advised to seek routine health check-ups in order to prevent the onset of various non-communicable diseases such as hypertension, type 2 diabetes, cancers, liver and kidney disorders [17]. Preventive health care practice is an important yet widely neglected factor that can avoid or slow the progression of any medical condition. It also opens the door for the assessment of well-being, especially in the elderly [18]. Therefore, understanding the need of the hour, it is crucial to identify the socio-economic and demographic factors that influence the routine medical check-up seeking behavior in the older adults in India. The study seeks to understand this profile of older adults residing in seven states of India and their health check-up seeking behavior and thereby identify the areas which need special attention in order to bring forth the importance of routine health check-ups. This study also tries to discover the aspects that encourage older adults to go through a routine health checkup. The study would be of immense help for the policy-makers to encourage a routine medical check-up by identifying the factors that prove to be a hurdle and intervening to rectify them.

Data source
The present research used data from Building a Knowledge Base on Population Aging in India (BKPAI), which was a national-level survey and was conducted in 2011, across seven states of India. The survey was sponsored by the Institute for social and economic change (ISEC), Tata Institute for social sciences (TISS), Institute for economic growth (IEG), and UNFPA, New Delhi. The survey gathered information on various socio-economic and health aspects of ageing among households of those aged 60 years and above with the written consent of the respondents.
Seven major regionally representative states were selected for the survey with the highest 60+ years population than the national average. This survey was carried out on a representative sample in the northern, western, eastern, and southern parts of India following a random sampling process.
The primary sampling unit (PSU) was villages for rural areas and urban wards in urban areas.
The sample of 1280 elderly households was fixed for each state. Further details on the sampling procedure, the sample size is available in national and state reports of BKPAI, 2011 [19]. For the current study, the effective sample size was of 9541 older adults residing in seven states aged 60+ years were selected.

Outcome variables
The routine medical check-up was the outcome variable of this study. The variable of health check-up was framed from the question that "Do you go for routine medical check-up?" The response was recoded as 0 means "no," and 1 means "yes."

Statistical analysis
Descriptive statistics and bivariate analysis were used to find the preliminary results. Further, multivariate analysis (binary logistic) has been done to fulfil the objectives of the study. The results were presented in the form of an odds ratio (OR) with a 95% confidence interval (CI).
The model is usually put into a more compact form as follows: Where 0 , … . . , are the regression coefficient indicating the relative effect of a particular explanatory variable on the outcome. These coefficients change as per the context in the analysis in the study.
Moreover, the wealth quintile was the key variable to measure the economic status of the household. A household wealth index was calculated in the survey by combining household amenities, assets, and durables and characterizing households in a range varying from the poorest to the richest, corresponding to wealth quintiles ranging from the lowest to the highest.
The study used wealth score (continuous variable) for decomposition analysis, and for the calculation of the Concentration Index (CI), the study used a wealth quintile, which was divided into five equal sizes of the population.

Concentration index
Concentration index represents the magnitude of inequality by measuring the area between the concentration curve and line of equality and calculated as twice the weighted covariance between the outcome and fractional rank in the wealth distribution divided by the variable mean.
The concentration index can be written as follows: Where, C is the concentration index; is the outcome variable index; R is the fractional rank of individual i in the distribution of socio-economic position; is the mean of the outcome variable of the sample, and denotes the covariance [20]. The index value lies between -1 to +1.
Further, the study decomposes the concentration index to understand the relative contribution of various socio-economic factors to the routine medical check-ups among older adults. To do this, the study used a regression-based decomposition technique, which was proposed by Wagstaff et al. [21]. In this model, routine medical check-up among older adults was considered as the outcome variable for assessing the effect of SES on inequalities.

Results:
The socio-demographic profile of older adults was presented in Table 1. Overall, about onefourth of the older adults went for medical check-ups. Three-fifth of the older adults belonged to 60-69 years age group, half of the older adults were women and illiterate. Nearly six percent of older adults were lived alone, 48% were economic dependent, and one-fourth of older adults were working. Around 65% of older adults were suffered from chronic diseases, and the majority of older adults were Hindu.
The percentage of older adults who went for routine medical check-ups were presented in Table   2. Estimates from logistic regression analysis for routine medical check-ups were presented in  Estimates from decomposition analysis for routine medical check-ups among older adults were presented in

Discussion:
Regular medical examination is a well-accepted form of preventive medicine. Routine medical check-up preferably involves a thorough history, physical examination, and screening of asymptomatic individuals by physicians on a timely basis [22]. A routine medical check-up is reckoned as an effective illness and promoting health and eliminating morbidity and mortality.
This study is therefore intended to examine routine medical check-ups by older adults in India and its associated factors. This study also examined observed socio-economic inequality in the highly educated older adults, richest older adults, and urban older adults were more likely to opt for a routine medical check-up than their counterparts. Furthermore, older adults with some chronic diseases were more likely to opt for a routine medical check-up than their counterparts [29].
Results from cross-tabulation noticed that a higher prevalence of women older adults were seeking routine medical check-ups than men older adults; however, this finding could not be statistically approved as the results from logistic regression could not find a significant relationship. Previously, various studies have noted that men tend to have lower levels of healthseeking than women [30]- [33], based on routinely collected primary care consultation data, observed that the consultation rate was much lower among men than in women. Women live longer than men, and as a result, they may have a higher number of visits to medical personnel for a routine check-up as compared to men [34]. However, few studies found that men older adults were more likely to seek health-care than women older adults [23], [35].
Education status is one of the important factors affecting routine medical check-ups among older adults. This study noticed that frequency of routine medical check-ups is higher among older adults with higher education. Previous studies have confirmed the positive association between education and routine medical check-up among older adults [36], [37]. Education enhances knowledge about the importance of routine health check-ups, which further brings a positive change in attitude and practice of routine medical check-ups among older adults [28]. Results profoundly concluded that older adults with chronic diseases were around 7.7 times more likely to opt for a routine medical check-up than their counterparts. The hospitalization rate is higher for chronic diseases as these can be deadly diseases, and hence people with chronic diseases are more likely to opt for a routine medical check-up [38].
Richest older adults were better at routine medical check-ups than poorest older adults. It is no paradox and can be attributed to the fact that richest older adults had enough money to invest in routine medical check-ups, while poorest older adults may not have enough money to go for a routine medical check-up. Rich-poor inequalities in health-care are widely documented across various settings, and researchers unanimously agreed that poor people tend to have low preventive care or routine medical check-up than richer people [39], [40]. Few researchers believe that poorer people tend to consume more health-care as they are sicker than richer people; however, richer people tend to have a more routine check-up as they have enough money to invest in preventive care [40]. The results from the decomposition analysis also found that wealth contributed to more than half of the observed socio-economic inequality in routine medical check-ups among older adults in India. Educational status of the older adults, chronic diseases among older adults, and wealth quintile of the households defined nearly 92 percent of the observed socio-economic inequality in routine health check-ups among older adults in India.
It means that education and wealth are the two important factors along with chronic disease among older adults that define socio-economic inequality in routine health check-ups. The rural-urban differentials in routine medical check-up are visible in this study. The routine medical check-up was higher among older adults in urban areas. People in rural areas may have less routine medical check-up due to various reasons accounting from the unavailability of doctors to low income among people in rural households [41], [42]. Furthermore, older adults in rural areas may have poor health literacy, which can further impact their routine medical check-up [43].
This study has some potential limitations. One of the predictor variables, namely chronic disease, was self-reported. However, it can be assumed that the self-reporting of chronic disease may not have much effect on the overall structure of the study. Furthermore, the cross-sectional nature of data limits our understanding of the causal relationship. Despite these limitations, this study provides first-hand information on routine medical check-ups among older adults in India.

Conclusion:
For 1. Ethics approval and consent to participate: The study is based on secondary data, which is in public domain and available on request. Therefore, ethical approval and consent to participate was taken by ISEC Bangalore.

Funding:
We declare that we did not receive any funding for this work.
3. Availability of data and material: We have provided details of the data in the methodology section. The BKPAI data can be obtained from the ISEC Bangalore. The report and the survey tools are also available on the website: https://india.unfpa.org/sites/default/files/pub-pdf/AgeingReport_2012_F.pdf

Authors' contributions:
Conception and design of the study: SS and PK; analysis and/or interpretation of data: SS and PK; drafting the manuscript: SC, RP and SG; revising the manuscript critically for important intellectual content: DW; reading and approving the manuscript: SS, PK, SC, RP, SG and DW.

Competing interests:
Authors declare that they do not have any competing interest.
6. Consent for publication: Not applicable.