Prevalence of disability in Tamil Nadu, India

Introduction

Disability is an umbrella term for impairments, activity limitations and participation restrictions.^[1] Based on the 2010 global population estimates, about 15% of the world's population is estimated to live with some form of disability.^[2] The Global Burden of Disease Report has estimated that around 975 million (19.4%) persons aged ≥15 years live with some disability with nearly 190 million (3.8%) having ‘severe disability’ such as quadriplegia, severe depression or blindness.^[3] In India, information on physical and mental disability is collected during the census once every 10 years and during periodic surveys by the National Sample Survey Office (NSSO).

Each state in India according to the Constitution has the responsibility, within the limits of its economic capacity and development, to make effective provision for securing the right to work, education and public assistance in case of unemployment, old age, sickness and disablement.^[4] Moreover, people with disabilities suffer undue hardships and they continue to be marginalized, discriminated and abused.^[4] It is essential that access to affordable healthcare and rehabilitation be offered to persons with disability. The state of Tamil Nadu has a better healthcare system, which is reflected in its better performance in key health indicators compared to other states.^[5] There is a need to quantify the burden of disability since this information is essential for the government to formulate policies, allocate adequate resources and implement appropriate intervention programmes for persons with disability.

According to the 2011 Census of India, 1 in every 50 Indian citizens (2.2%) is either physically or mentally disabled.^[6] We aimed to measure the prevalence of disability and describe types of disability in Tamil Nadu based on the Census 2011 data. We also estimated the distribution of disabilities by gender, age and geographical regions.

Methods

The Census in India is conducted once every 10 years. The 2011 Census questionnaire had three questions pertaining to disability which captured information on (i) presence of mental or physical disability (Yes 1, No 2); (ii) disability type (seeing 1, hearing 2, speech 3, movement 4, mental retardation 5, mental illness 6, any other 7, multiple 8); and (iii) the nature of disabilities (maximum of 3) in people in whom the response to the second question was ‘multiple disability’.^[7]

The procedure for enumeration of disability in the census survey and definitions used for various types of disability are outlined in the Manual on Disability Statistics.^[7]

Data analysis

Disability rates per 100 000 population were calculated. The 2011 data from C20 Table pertaining to Tamil Nadu was used for the numerator which consisted of the number of disabled persons by type of disability, age, gender and type of residence (rural/urban).^[8]

The denominator was obtained from C-14 five-year age group data by residence and sex from Census 2011. This table provides information on the number of people in Tamil Nadu as well as in districts in various age groups (5 yearly) starting from 0–4 years, up to 75–79 years and 85+ years. In addition, information on residence (rural/urban) and gender was used.^[9] The following tables from Census 2011 were used to calculate disability rates related to literacy level, marital status, work status and social group: PCA-33, DDW-3300C-02-fer3-MDDS, DISAB03-0000, DDW-0000C-21, DDW-0000C-23, DISAB04SC-0000, DISAB04ST-0000.^[10]

Age-adjusted disability rates calculated by the direct standardization method were used for comparison and ranking of the districts with respect to each type of disability. The 2011 population of Tamil Nadu with the following age intervals: 0–4 years, 5–9 years, 10–19 years, 20–29 years, 30–39 years, 40–49 years, 50–59 years, 60–69 years, 70–79 years, 80+years, and age not stated was used as the standard population for calculating the age-adjusted disability rates. The data were analysed using Microsoft Excel windows 2007.

Results

There were 1 179 963 individuals with disability in Tamil Nadu in 2011 accounting for a disability rate of 1635 per 100 000 population (1.6%; 2011 population of Tamil Nadu: 72 147 030). The disability in movement, hearing and seeing was most predominant with rates of 398, 305 and 177 per 100 000, respectively. Disability rates in mental retardation, multiple disability, speech and mental illness were 140, 129, 111 and 46, respectively. Disability in movement, hearing and seeing individually accounted for 24%, 19% and 11% of the total disability burden. In addition, mental retardation, multiple disability, disability in speech and mental illness constituted 9%, 8%, 7% and 3% of the total disability, respectively. The remaining about 20% of disability was due to other causes.

Disability rates in districts of Tamil Nadu

Of the 32 districts, age-standardized disability rates in 16 districts were above the state average of 1635 per 100 000 population and ranged from 2071 to 1652 per 100 000 population [Table - 1] and [Figure - 1]. Thiruvarur, Thiruvallur and Ariyalur districts had the highest disability rates of 2071, 2028 and 1991 per 100 000 population, respectively. Salem and Karur districts had the lowest rates of 1247 and 1294 per 100 000 population, respectively.

Table 1: Age-standardized disability rates per 100 000 according to type of disability in districts of Tamil Nadu, 2011

Figure 1: Age-standardized disability rates per 100 000 in the districts of Tamil Nadu, 2011

Disability in seeing, hearing, movement and speech was highest in Thiruvarur (238 per 100 000), Chennai (501 per 100 000), Thoothukkudi (512 per 100 000) and Perambalur (198 per 100 000), respectively [Table - 1]. Mental retardation (183 per 100 000) and mental illness (86 per 100 000) were high in Nagapattinam and Kanniyakumari, respectively. Ariyalur had a high multiple disability rate (171 per 100 000; [Table - 1].

Disability rates by demographic variables

Disability rates increased as age advanced with the highest rate of 2533 per 100 000 among people aged 60 years and above [Table - 2]. The disability rates were higher in males and in rural areas [Table - 2]. The disability rates in males and females in the rural areas of India were 1857 v. 1482 per 100 000, respectively compared to 1779 v. 1418 per 100 000 in the urban areas. The disability rate among the Scheduled Castes was higher (1763 per 100 000) compared to the Scheduled Tribes and other social groups. Higher disability rates were also observed among illiterates (2285 per 100 000), non-working (1879 per 100 000) and widowed, separated and divorced (2448 per 100 000) people [Table - 2]. Analysis of disabilities by age (categorized as 0–19 years, 20–39 years, 40–59 years, and 60 years and above), gender and type of residence (urban/rural) showed that disability rates were higher in rural areas and there was a male preponderance in disability rates in both rural and urban areas across different age groups.

Table 2: Disability rates by basic demographic variables in Tamil Nadu, 2011

Types of disability by age, gender and residence

Disability rates associated with movement, hearing and seeing increased as age advanced with rates of 714, 607 and 444 per 100 000, respectively in the age group 60 years and above [Table - 3]. Mental retardation decreased with advancing age and was highest with 183 per 100 000 in the age group 0–19 years. Mental illness was high in the age group 40–59 years with a disability rate of 79 per 100 000. Disability in speech was high among the 20–39-year-olds and decreased thereafter. Multiple disabilities were more common in extremes of age with rates of 141 and 155 per 100 000 in the age groups 0–19 years and ≥60 years, respectively.

Table 3: Differences in type of disability based on age groups

Disability in movement, seeing, speech and multiple disabilities showed male and rural predominance across all age categories [Table - 4] and [Figure - 2]. Hearing-related disability was higher in urban areas across age groups 0–59 years and thereafter there was a rural predominance in those ≥60 years. Both genders had almost similar hearing-related disability rates across all age categories. Mental retardation was higher in males, had a rural predominance up to 39 years and after that was higher in urban areas. Mental illness was almost similar in rural and urban areas in all age groups except in those in the age group 20–39 years, which had a rural predominance (57 v. 49 per 100 000). Male predominance was observed in mental illness both in rural and urban areas up to 59 years of age with a female predominance thereafter.

Table 4: Disability rates by age, gender and location of residence (urban/rural) according to the type of disability in Tamil Nadu, 2011

Figure 2: Disability rates by age, gender and location of residence (urban/rural) according to the type of disability in Tamil Nadu, 2011

Discussion

We observed that about 1 in every 100 person in Tamil Nadu (1635 per 100 000 persons) is either physically or mentally disabled based on the data of Census 2011. This is similar to the analysis of 14 household surveys from 13 developing countries, which suggested that 1%–2% of the population have disabilities.^[11] In the USA, overall 22.2% of adults reported any disability in 2013.^[12] However, the prevalence rates for disability are not strictly comparable owing to the differences in the definition used. The percentage of disabled population to total population in Tamil Nadu (1.6%) is lower compared to other states and Union Territories.^[6] The states of Jammu and Kashmir, Sikkim and Odisha had 2.9% disabled in their population.^[6] Assam, Meghalaya and Mizoram had lower disabled population (< 1.5%) compared to Tamil Nadu.^[6] The reason for Tamil Nadu to have a lower proportion of population with disability could be better healthcare facilities and access to healthcare compared to that of other states. However, this needs further exploration and research for varied disability rates across different states in India.

The higher disability rates in rural areas compared to urban (1.6% v. 1.5%) in Tamil Nadu reflect the overall Indian scenario, which showed disability rates of 2.2% v. 2.1%.^[6] It is possible that higher disability rates in rural areas are due to lack of adequate facilities and healthcare. In addition, geographical variation, i.e. urban or rural in the distribution of types of disability observed in our analysis needs to be explored further to generate evidence that would help in designing locally relevant interventions. The observation of male predominance in disabilities with 1.8% and 1.7% disability in rural and urban areas, respectively in this analysis is similar to that of higher disability rates in India among males which was 2.4% and 2.3% in rural and urban areas, respectively compared to that of females.^[6] This highlights the need to address the gender and rural/urban angle in the disability burden through appropriate strategies for concerned groups.

Comparison of the prevalence of different types of disability observed in Tamil Nadu with that of India showed that disability in mental retardation to be higher in Tamil Nadu (140 v. 124 per 100 000).^[8],[9] The reasons for mental retardation documented in the 2002 NSSO survey of India were serious illness or head injury during childhood, pregnancy and birth-related effects and hereditary disorders.^[13] Additional research is essential in mental retardation especially in districts such as Nagapattinam, Kanniyakumari, Thoothukkudi and Tirunelveli which had mental retardation rates beyond 170 per 100 000.

Old age, other illnesses and injury featured among the main reasons for movement, visual, hearing, speech disability in the country-wide NSSO survey 2002 on disability.^[13] The other reasons identified in the survey according to the type of disability were poliomyelitis, cerebral palsy, leprosy, stroke, arthritis for movement-related disability; cataract, corneal opacity, glaucoma, eye diseases for visual disability; ear discharge; noise-induced hearing loss for disability related to hearing and voice disorder, paralysis, injury, mental retardation, mental illness, cleft palate/ lip resulting in speech-related disability.^[13] Understanding the causes of disability is important to plan appropriate preventive strategies and research is warranted in this area.

‘Elderly’ is defined as a person who is 60 years or more in age.^[14] We observed the burden of disability to be high in the elderly in Tamil Nadu. This would probably increase since the proportion of the elderly (≥60 years) in India by 2026 is projected to be 12.17% of the overall population compared to 8.6% in 2011.^[15] The observation of high burden of mental retardation, multiple disability in the age group of 0–19 years (children) and movement, hearing-related disability between 20 and 59 years (economically productive age group) in our analysis is a matter of concern. Identification of factors and predictors of disability in these categories through research studies is critical.

Persons with disability could have been disadvantaged in getting educated, employed or married and this might be reflecting high disability rates in those sections of the population observed in our analysis. Lower educational attainment among adults with disabilities has been reported from developing countries.^[11] In the USA, lower prevalence of disability was observed in adults with higher levels of education and among those employed.^[12] A study from the Organization for Economic Co-operation and Development (OECD) in 27 countries reported that persons with disability have significantly lower levels of education and working-age persons with disabilities experience significant labour market disadvantage than working-age persons without disabilities.^[16] The lives of disabled people are affected by poor health outcomes, lower educational achievements, less economic participation, high rates of poverty and increased dependency.^[2] The Government of Tamil Nadu is responsive to the needs of the disabled and offers many schemes and scholarships for rehabilitation of the disabled. These include special education, training, reservation of jobs/ seats in educational institutions, financial assistance, assistive devices and care centres.^[17] However, a focus group multicentered study in India done in Chennai, Bengaluru and Delhi among persons with physical, mental and alcohol/drug-related disability has revealed problems pertaining to discrimination, poor awareness regarding social programmes and under-utilization of the available resources to be primarily related to stigmatization of individuals with specific disabilities.^[18] The programme managers have to address the barriers to healthcare, rehabilitation, education, employment, support and assistance services and create enabling environments.^[2] Rehabilitation builds human capacity and there should be emphasis on early intervention.^[2] Integrating rehabilitation into primary and secondary healthcare settings can improve its availability. In addition, training programmes for capacity building of rehabilitation professionals are essential to ensure a continuum of care.^[2] Access to assistive technologies has to be improved in terms of availability and affordability.

In India, the Chief Commissioner for Persons with Disabilities at the Centre and a Commissioner in each state are appointed to safeguard the rights of persons with disabilities.^[19] In addition, the National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke Programme, National Mental Health Programme, National Programme for Prevention and Control of Deafness, National Programme for Health Care of the Elderly and National Blindness Control Programme have a major role in providing preventive, curative and rehabilitative services to reduce the burden of disability in their areas of operation. Early detection and management of comorbid illness and visual impairment, prevention of injury and addressing noise pollution could potentially prevent disabilities.

The strengths of the Census survey include its implementation through universal reach and use of standardized protocols in data collection. However, there are limitations due to non-response and under-reporting might result due to inability to capture the complex and sensitive information related to disability. To estimate the current burden of disability in Tamil Nadu, appropriate statistical modelling will have to be applied to the Census data of 2011.

Disability rates reflect the overall health status of the population. We have presented the estimates of disability prevalence, geographical and gender differentials in the disability rates in Tamil Nadu. To understand the reasons, additional research studies will have to be planned. Implementing effective and focused strategies for prevention will help to reduce the burden of disability in Tamil Nadu in the years to come.

Acknowledgements

We acknowledge the Office of the Registrar General and Census Commissioner, India for providing access to the data on disability and population enumeration which was used for the analysis.

Conflict of interest. None declared.